Changed msync to actually sync

This copies xnbd's style

.gitignore

@@ -0,0 +1,9 @@
+**/*.o
+**/*~
+flexnbd
+build/
+pkg/
+**/*.orig
+**/.*.swp
+cscope.out
+valgrind.out

.gitlab-ci.yml

@@ -0,0 +1,27 @@
+stages:
+  - package
+  - publish
+ 
+package:jessie: &package
+  stage: package
+  image: $CI_REGISTRY/docker-images/layers:$DISTRO-deb
+  variables:
+    DISTRO: jessie
+  script:
+    - package
+  artifacts:
+    paths:
+      - pkg/
+
+package:stretch:
+  <<: *package
+  variables:
+    DISTRO: stretch
+
+publish:
+  stage: publish
+  tags: 
+    - shell
+  script:
+    - publish
+

.hgignore

@@ -1,9 +0,0 @@
-.o$
-~$
-^flexnbd$
-^build/
-^pkg/
-\.orig$
-.*\.swp$
-cscope.out$
-valgrind.out$

Makefile

@@ -0,0 +1,121 @@
+#!/usr/bin/make -f
+
+VPATH=src:tests/unit
+DESTDIR?=/
+PREFIX?=/usr/local/bin
+INSTALLDIR=$(DESTDIR)/$(PREFIX)
+
+ifdef DEBUG
+	CFLAGS_EXTRA=-g -DDEBUG
+	LDFLAGS_EXTRA=-g
+else
+	CFLAGS_EXTRA=-O2
+endif
+
+NO_MSYNC=1
+ifdef NO_MSYNC
+	CFLAGS_EXTRA += -DNO_MSYNC
+endif
+
+CFLAGS_EXTRA  += -fPIC --std=gnu99
+LDFLAGS_EXTRA += -Wl,--relax,--gc-sections -L$(LIB) -Wl,-rpath-link,$(LIB)
+
+# The -Wunreachable-code warning is only implemented in clang, but it
+# doesn't break anything for gcc to see it.
+WARNINGS=-Wall \
+				 -Wextra \
+				 -Werror-implicit-function-declaration \
+				 -Wstrict-prototypes \
+				 -Wno-missing-field-initializers \
+				 -Wunreachable-code
+
+CCFLAGS=-D_GNU_SOURCE=1 $(WARNINGS) $(CFLAGS_EXTRA) $(CFLAGS)
+LLDFLAGS=-lm -lrt -lev $(LDFLAGS_EXTRA) $(LDFLAGS)
+
+CC?=gcc
+
+LIBS=-lpthread
+INC=-I/usr/include/libev -Isrc/common -Isrc/server -Isrc/proxy
+COMPILE=$(CC) -MMD $(INC) -c $(CCFLAGS)
+LINK=$(CC) $(LLDFLAGS) -Isrc $(LIBS)
+
+LIB=build/
+
+COMMON_SRC  := $(wildcard src/common/*.c)
+SERVER_SRC := $(wildcard src/server/*.c)
+PROXY_SRC   := $(wildcard src/proxy/*.c)
+
+COMMON_OBJ  := $(COMMON_SRC:src/%.c=build/%.o)
+SERVER_OBJ := $(SERVER_SRC:src/%.c=build/%.o)
+PROXY_OBJ   := $(PROXY_SRC:src/%.c=build/%.o)
+
+SRCS := $(COMMON_SRC) $(SERVER_SRC) $(PROXY_SRC)
+OBJS := $(COMMON_OBJ) $(SERVER_OBJ) $(PROXY_OBJ)
+
+
+all: build doc
+
+build: server proxy
+
+build/%.o: %.c
+	mkdir -p $(dir $@)
+	$(COMPILE) $< -o $@
+
+objs: $(OBJS)
+
+build/flexnbd: $(COMMON_OBJ) $(SERVER_OBJ) build/main.o
+	$(LINK) $^ -o $@
+
+build/flexnbd-proxy: $(COMMON_OBJ) $(PROXY_OBJ) build/proxy-main.o
+	$(LINK) $^ -o $@
+
+server: build/flexnbd
+
+proxy: build/flexnbd-proxy
+
+CHECK_SRC := $(wildcard tests/unit/*.c)
+CHECK_OBJ := $(CHECK_SRC:tests/unit/%.c=build/%.o)
+# Why can't we reuse the build/%.o rule above? Not sure.
+
+CHECK_BINS := $(CHECK_SRC:tests/unit/%.c=build/%)
+
+build/check_%: build/check_%.o
+	$(LINK) $^ -o $@ $(COMMON_OBJ) $(SERVER_OBJ) -lcheck -lsubunit
+
+check_objs: $(CHECK_OBJ)
+
+check_bins: $(CHECK_BINS)
+
+check: $(OBJS) $(CHECK_BINS)
+	r=true ; for bin in $(CHECK_BINS); do $$bin || r=false; done ; $$r
+
+acceptance: build
+	cd tests/acceptance && RUBYOPT='-I.' ruby nbd_scenarios -v
+
+test: check acceptance
+
+build/flexnbd.1: README.txt
+	txt2man -t flexnbd -s 1 $< > $@
+
+build/flexnbd-proxy.1: README.proxy.txt
+	txt2man -t flexnbd-proxy -s 1 $< > $@
+
+# If we don't pipe to file, gzip clobbers the original, causing make
+# to rebuild each time
+%.1.gz: %.1
+	gzip -c -f $< > $@
+
+doc: build/flexnbd.1.gz build/flexnbd-proxy.1.gz
+
+install:
+	mkdir -p $(INSTALLDIR)
+	cp build/flexnbd build/flexnbd-proxy $(INSTALLDIR)
+
+clean:
+	rm -rf build/*
+
+
+.PHONY: clean objs check_objs all server proxy check_bins check doc build test acceptance
+
+# Include extra dependencies at the end, NOT before 'all'
+-include $(wildcard build/*.d)

README.proxy.txt

@@ -0,0 +1,206 @@
+NAME
+
+ flexnbd-proxy - A simple NBD proxy
+
+SYNOPSIS
+
+  flexnbd-proxy --addr ADDR [--port PORT] --conn-addr ADDR
+    --conn-port PORT [--bind ADDR] [--cache[=CACHE_BYTES]] 
+    [--help] [--verbose] [--quiet]
+
+DESCRIPTION
+
+flexnbd-proxy is a simple NBD proxy server that implements resilient
+connection logic for the client. It connects to an upstream NBD server
+and allows a single client to connect to it. All server properties are
+proxied to the client, and the client connection is kept alive across
+reconnections to the upstream server. If the upstream goes away while
+an NBD request is in-flight then the proxy (silently, from the point
+of view of the client) reconnects and retransmits the request, before
+returning the response to the client.
+
+USAGE
+
+Proxy requests from an NBD client to an NBD server, resiliently. Only one
+client can be connected at a time, and ACLs cannot be applied to the client, as they 
+can be to clients connecting directly to a flexnbd in serve mode.
+
+On starting up, the proxy will attempt to connect to the server specified by
+--conn-addr and --conn-port (from the address specified by --bind, if given). If
+it fails, then the process will die with an error exit status.
+
+Assuming a successful connection to the `upstream` server is made, the proxy
+will then start listening on the address specified by --addr and --port, waiting
+for `downstream` to connect to it (this will be your NBD client). The client
+will be given the same hello message as the proxy was given by the server.
+
+When connected, any request the client makes will be read by the proxy and sent
+to the server. If the server goes away for any reason, the proxy will remember
+the request and regularly (~ every 5 seconds) try to reconnect to the server.
+Upon reconnection, the request is sent and a reply is waited for. When a reply
+is received, it is sent back to the client.
+
+When the client disconnects, cleanly or otherwise, the proxy goes back to
+waiting for a new client to connect. The connection to the server is maintained
+at that point, in case it is needed again.
+
+Only one request may be in-flight at a time under the current architecture; that
+doesn't seem to slow things down much relative to alternative options, but may
+be changed in the future if it becomes an issue.
+
+OPTIONS
+
+  --addr, -l ADDR  
+    The address to listen on. If this begins with a '/', it is assumed to be
+    a UNIX domain socket to create. Otherwise, it should be an IPv4 or IPv6
+    address.
+
+  --port, -p PORT  
+    The port to listen on, if --addr is not a UNIX socket. 
+
+  --conn-addr, -C ADDR  
+    The address of the NBD server to connect to. Required.
+
+  --conn-port, -P PORT  
+    The port of the NBD server to connect to. Required.
+
+  --cache, -c=CACHE_BYTES  
+    If given, the size in bytes of read cache to use. CACHE_BYTES
+    defaults to 4096.
+
+  --help, -h  
+    Show command or global help.
+
+  --verbose, -v  
+    Output all available log information to STDERR.
+
+  --quiet, -q  
+    Output as little log information as possible to STDERR.
+
+LOGGING
+
+Log output is sent to STDERR. If --quiet is set, no output will be
+seen unless the program termintes abnormally. If neither --quiet nor
+--verbose are set, no output will be seen unless something goes wrong
+with a specific request. If --verbose is given, every available log
+message will be seen (which, for a debug build, is many). It is not an
+error to set both --verbose and --quiet. The last one wins.
+
+The log line format is:
+
+    <TIMESTAMP>:<LEVEL>:<PID> <THREAD> <SOURCEFILE>:<SOURCELINE>: <MSG>
+
+<TIMESTAMP>  
+  Time the log entry was made. This is expressed in terms of monotonic ms
+
+<LEVEL>  
+  This will be one of 'D', 'I', 'W', 'E', 'F' in increasing order of
+  severity. If flexnbd is started with the --quiet flag, only 'F' will
+  be seen. If it is started with the --verbose flag, any from 'I'
+  upwards will be seen. Only if you have a debug build and start it
+  with --verbose will you see 'D' entries.
+
+<PID>  
+  This is the process ID.
+
+<THREAD>  
+  flexnbd-proxy is currently single-threaded, so this should be the
+  same for all lines. That may not be the case in the future.
+
+<SOURCEFILE:SOURCELINE>  
+  Identifies where in the source code this log line can be found.
+
+<MSG>  
+  A short message describing what's happening, how it's being done, or
+  if you're very lucky why it's going on.
+
+EXAMPLES
+
+The main point of the proxy mode is to allow clients that would otherwise break
+when the NBD server goes away (during a migration, for instance) to see a
+persistent TCP connection throughout the process, instead of needing its own
+reconnection logic.
+
+For maximum reliability, the proxy process would be run on the same machine as
+the actual NBD client; an example might look like:
+
+  nbd-server-1$ flexnbd serve -l 10.0.0.1 -p 4777 myfile [...]
+
+  nbd-client-1$ flexnbd-proxy -l 127.0.0.1 -p 4777 -C 10.0.0.1 -P 4777
+  nbd-client-1$ nbd-client -c 127.0.0.1 4777 /dev/nbd0
+
+  nbd-server-2$ flexnbd listen -l 10.0.0.2 -p 4777 -f myfile [...]
+
+  nbd-server-1$ flexnbd mirror --addr 10.0.0.2 -p 4777 [...]
+
+Upon completing the migration, the mirroring and listening flexnbd servers will
+both exit. With the proxy mediating requests, this does not break the TCP
+connection that nbd-client is holding open. If no requests are in-flight, it
+will not notice anything at all; if requests are in-flight, then the reply may
+take longer than usual to be returned.
+
+When flexnbd is restarted in serve mode on the second server:
+
+  nbd-server-2$ flexnbd serve -l 10.0.0.1 -p 4777 -f myfile [...]
+
+The proxy notices and reconnects, fulfiling any request it has in its buffer.
+The data in myfile has been moved between physical servers without the nbd
+client process having to be disturbed at all.
+
+READ CACHE
+
+If the --cache option is given at the command line, either without an
+argument or with an argument greater than 0, flexnbd-proxy will use a
+read-ahead cache. The cache as currently implemented doubles each read
+request size, up to a maximum of 2xCACHE_BYTES, and retains the latter
+half in a buffer. If the next read request from the client exactly
+matches the region held in the buffer, flexnbd-proxy responds from the
+cache without making a request to the server.
+
+This pattern is designed to match sequential reads, such as those
+performed by a booting virtual machine.
+
+Note: If specifying a cache size, you must use this form:
+
+  nbd-client$ flexnbd-proxy --cache=XXXX
+
+That is, the '=' is required. This is a limitation of getopt-long.
+
+If no cache size is given, a size of 4096 bytes is assumed. Caching can
+be explicitly disabled by setting a size of 0.
+
+BUGS
+
+Should be reported via GitHub.
+
+* https://github.com/BytemarkHosting/flexnbd-c/issues
+
+Current issues include:
+
+* only old-style NBD negotiation is supported;
+* only one request may be in-flight at a time;
+* all I/O is blocking, and signals terminate the process immediately;
+* UNIX socket support is limited to the listen address;
+* FLUSH and TRIM commands, and the FUA flag, are not supported;
+* DISCONNECT requests do not get passed through to the NBD server;
+* no active timeout-retry of requests - we trust the kernel's idea of
+  failure.
+
+AUTHOR
+
+Originally written by Alex Young <alex@blackkettle.org>.
+Original concept and core code by Matthew Bloch <matthew@bytemark.co.uk>.
+Proxy mode written by Nick Thomas <me@ur.gs>.
+
+The full commit history is available on GitHub.
+
+SEE ALSO
+
+flexnbd(1), nbd-client(8), xnbd-server(8), xnbd-client(8)
+
+COPYRIGHT
+
+Copyright (c) 2012-2016 Bytemark Hosting Ltd. Free use of this
+software is granted under the terms of the GNU General Public License
+version 3 or later.
+

README.txt

@@ -1,17 +1,36 @@
-FLEXNBD(1)
-==========
-:doctype: manpage
-
 NAME
-----
+
 flexnbd - A fast NBD server
 
 SYNOPSIS
---------
-*flexnbd* 'COMMAND' ['OPTIONS']
+
+  flexnbd MODE [ ARGS ]
+
+  flexnbd serve --addr ADDR --port PORT --file FILE [--sock SOCK]
+    [--default-deny] [--killswitch] [global_option]* [acl_entry]*
+
+  flexnbd listen --addr ADDR --port PORT --file FILE [--sock SOCK]
+    [--default-deny] [global_option]* [acl_entry]*
+
+  flexnbd mirror --addr ADDR --port PORT --sock SOCK [--unlink]
+    [--bind BIND_ADDR] [global_option]*
+
+  flexnbd acl --sock SOCK [acl_entry]+ [global_option]*
+
+  flexnbd break --sock SOCK [global_option]*
+
+  flexnbd status --sock SOCK [global_option]*
+
+  flexnbd read --addr ADDR --port PORT --from OFFSET --size SIZE
+    [--bind BIND_ADDR] [global_option]*
+
+  flexnbd write --addr ADDR --port PORT --from OFFSET --size SIZE
+    [--bind BIND_ADDR] [global_option]*
+
+  flexnbd help [mode] [global_option]*
 
 DESCRIPTION
------------
+
 Flexnbd is a fast NBD server which supports live migration. Live
 migration is performed by writing the data to a new server. A failed
 migration will be invisible to any connected clients.
@@ -19,275 +38,290 @@ migration will be invisible to any connected clients.
 Flexnbd tries quite hard to preserve sparsity of files it is serving,
 even across migrations.
 
-COMMANDS
---------
+SERVE MODE
 
-serve
-~~~~~
-  $ flexnbd serve --addr <ADDR> --port <PORT> --file <FILE> 
-    [--sock <SOCK>] [--default-deny] [global option]* [acl entry]*
+Serve a file.
 
-Serve a file. If any ACL entries are given (which should be IP
+  $ flexnbd serve --addr <ADDR> --port <PORT> --file <FILE>
+      [--sock <SOCK>] [--default-deny] [-k] [global_option]*
+      [acl_entry]*
+
+If any ACL entries are given (which should be IP
 addresses), only those clients listed will be permitted to connect.
 
 flexnbd will continue to serve until a SIGINT, SIGQUIT, or a successful
 migration.
 
-Options
-^^^^^^^
+  OPTIONS
 
-*--addr, -l ADDR*:
+  --addr, -l ADDR  
     The address to listen on. Required.
 
-*--port, -p PORT*:
+  --port, -p PORT  
     The port to listen on. Required.
 
-*--file, -f FILE*:
+  --file, -f FILE  
     The file to serve. Must already exist. Required.
 
-*--sock, -s SOCK*:
-    Path to a control socket to open.  You will need this if you want to
+  --sock, -s SOCK  
+    Path to a control socket to open. You will need this if you want to
     migrate, get the current status, or manipulate the access control
     list.
 
-*--default-deny, -d*:
-    How to interpret an empty ACL.  If --default-deny is given, an
-    empty ACL will let no clients connect.  If it is not given, an
+  --default-deny, -d  
+    How to interpret an empty ACL. If --default-deny is given, an
+    empty ACL will let no clients connect. If it is not given, an
     empty ACL will let any client connect.
-    
-listen
-~~~~~~
 
-  $ flexnbd listen --addr <ADDR> --port <PORT> --file <FILE> 
-    [--rebind-addr <REBIND-ADDR>] [--rebind-port <REBIND-PORT>]
-    [--sock <SOCK>] [--default-deny] [global option]* [acl entry]*
+  --killswitch, -k  
+    If set, we implement a 2-minute timeout on NBD requests and
+    responses. If a request takes longer than that to complete,
+    the client is disconnected. This is useful to keep broken
+    clients from breaking migrations, among other things.
 
-Listen for an inbound migration, then serve it as normal once it has
-completed.
+LISTEN MODE
 
-flexnbd will wait for a successful migration, and then switch into
-'serve' mode. The file to write the inbound migration data to must
-already exist before you run 'flexnbd listen'.
+Listen for an inbound migration, and quit with a status of 0 on
+completion.
 
-Only one sender may connect to send data, and the server is not
-available to clients while the migration is taking place.
+  $ flexnbd listen --addr ADDR --port PORT --file FILE
+      [--sock SOCK] [--default-deny] [global_option]* 
+      [acl_entry]*
 
-If the sender disconnects part-way through the migration, the
-destination will expect it to reconnect and retry the whole migration.
-It isn't safe to assume that a partial migration can be resumed because
-the destination has no knowledge of whether a client has made a write to
+flexnbd will wait for a successful migration, and then quit. The file
+to write the inbound migration data to must already exist before you
+run 'flexnbd listen'.
+
+Only one sender may connect to send data, and if the sender
+disconnects part-way through the migration, the destination will
+expect it to reconnect and retry the whole migration. It isn't safe
+to assume that a partial migration can be resumed because the
+destination has no knowledge of whether a client has made a write to
 the source in the interim.
 
-To support transparently replacing an existing server, flexnbd can
-switch addresses once it has received a successful migration. 
+If the migration fails for a reason which the 'flexnbd listen' process
+can't fix (say, a failed local write), it will exit with an error
+status. In this case, the sender will continually retry the migration
+until it succeeds, and you will need to restart the 'flexnbd listen'
+process to allow that to happen.
 
-Options
-^^^^^^^
-As for 'serve', with these additions:
+  OPTIONS
 
-*--rebind-addr, -L REBIND_ADDR*:
-  The address to rebind to once migration has completed.
+As for serve.
 
-*--rebind-port, -P REBIND_PORT*:
-  The port to rebind to once migration has completed.
-
-Either, both, or neither of --rebind-port and rebind-addr may be given.
-If rebinding fails, flexnbd will retry every second until it succeeds.
-
-mirror
-~~~~~~
-
-  $ flexnbd mirror --addr <ADDR> --port <PORT> --sock SOCK 
-      [--bind <BIND-ADDR>] [global option]*
+MIRROR MODE
 
 Start a migration from the server with control socket SOCK to the server
 listening at ADDR:PORT.
 
+  $ flexnbd mirror --addr ADDR --port PORT --sock SOCK [--unlink]
+      [--bind BIND_ADDR] [global_option]*
+
 Migration can be a slow process. Rather than block the 'flexnbd mirror'
 process until it completes, it will exit with a message of "Migration
 started" once it has confirmation that the local server was able to
-connect to ADDR:PORT and got an NBD header back.  To check on the
+connect to ADDR:PORT and got an NBD header back. To check on the
 progress of a running migration, use 'flexnbd status'.
 
 If the destination unexpectedly disconnects part-way through the
 migration, the source will attempt to reconnect and start the migration
-again.  It is not safe to resume the migration from where it left off
+again. It is not safe to resume the migration from where it left off
 because the source can't see that the backing store behind the
 destination is intact, or even on the same machine.
 
-Note: files smaller than 4096 bytes cannot be migrated.
+If the --unlink option is given, the local file will be deleted
+immediately before the mirror connection is terminated. This allows
+an otherwise-ambiguous situation to be resolved: if you don't unlink
+the file and the flexnbd process at either end is terminated, it's not
+possible to tell which copy of the data is canonical. Since the
+unlink happens as soon as the sender knows that it has transmitted all
+the data, there can be no ambiguity.
 
-Options
-^^^^^^^
+Note: files smaller than 4096 bytes cannot be mirrored.
 
-*--addr, -l ADDR*:
-  The address of the remote server to migrate to. Required.
+  OPTIONS
 
-*--port, -p PORT*:
-  The port of the remote server to migrate to. Required.
+  --addr, -l ADDR  
+    The address of the remote server to migrate to. Required.
 
-*--sock, -s SOCK*:
-  The control socket of the local server to migrate from. Required.
+  --port, -p PORT  
+    The port of the remote server to migrate to. Required.
 
-*--bind, -b BIND-ADDR*:
-  The local address to bind to. You may need this if the remote server
-  is using an access control list.
+  --sock, -s SOCK  
+    The control socket of the local server to migrate from. Required.
 
-acl
-~~~
+  --unlink, -u  
+    Unlink the served file from the local filesystem after
+    successfully mirroring.
 
-  $ flexnbd acl --sock <SOCK> [acl entry]+ [global option]*
+  --bind, -b BIND_ADDR  
+    The local address to bind to. You may need this if the remote
+    server is using an access control list.
+
+BREAK MODE
+
+Stop a running migration.
+
+  $ flexnbd break --sock SOCK [global_option]*
+
+  OPTIONS
+
+  --sock, -s SOCK  
+    The control socket of the local server whose migration to stop.
+    Required.
+
+ACL MODE
 
 Set the access control list of the server with the control socket SOCK
 to the given access control list entries.
 
+  $ flexnbd acl --sock SOCK [acl_entry]+ [global_option]*
+
 ACL entries are given as IP addresses.
 
-Options
-^^^^^^^
+  OPTIONS
 
-*--sock, -s SOCK*:
-  The control socket of the server whose ACL to replace.
+  --sock, -s SOCK  
+    The control socket of the server whose ACL to replace. Required
 
-status
-~~~~~~
-
-  $ flexnbd status --sock <SOCK> [global option]*
+STATUS MODE
 
 Get the current status of the server with control socket SOCK.
 
-The status will be printed to STDOUT.  It is a space-separated list of
-key=value pairs.  The space character will never appear in a key or
-value.  Currently reported values are:
+  $ flexnbd status --sock SOCK [global_option]*
 
-*is_mirroring*:
+The status will be printed to STDOUT. It is a space-separated list of
+key=value pairs. The space character will never appear in a key or
+value. Currently reported values are:
+
+pid  
+  The process id of the server listening on SOCK.
+
+is_mirroring  
   'true' if this server is sending migration data, 'false' otherwise.
 
-*has_control*:
-  'false' if this server was started in 'listen' mode and has not yet
-  received a successful migration. 'true' otherwise.
+has_control  
+  'false' if this server was started in 'listen' mode. 'true' otherwise.
 
-read
-~~~~
+  OPTIONS
 
-  $ flexnbd read --addr <ADDR> --port <PORT> --from <OFFSET> 
-    --size <SIZE>  [--bind BIND-ADDR] [global option]*
+  --sock, -s SOCK  
+    The control socket of the server of interest. Required.
+
+READ MODE
 
 Connect to the server at ADDR:PORT, and read SIZE bytes starting at
-OFFSET in a single NBD query.  The returned data will be echoed to
-STDOUT.  In case of a remote ACL, set the local source address to
-BIND-ADDR.
+OFFSET in a single NBD query.
 
-Options
-^^^^^^^
+  $ flexnbd read --addr ADDR --port PORT --from OFFSET --size SIZE
+      [--bind BIND_ADDR] [global_option]*
 
-*--addr, -l ADDR*:
-  The address of the remote server.  Required.
+The returned data will be echoed to STDOUT. In case of a remote ACL,
+set the local source address to BIND_ADDR.
 
-*--port, -p PORT*:
-  The port of the remote server.  Required.
+  OPTIONS
 
-*--from, -F OFFSET*:
-  The byte offset to start reading from. Required. Maximum 2^62.
+  --addr, -l ADDR  
+    The address of the remote server. Required.
 
-*--size, -S SIZE*:
-  The number of bytes to read. Required.  Maximum 2^30.
+  --port, -p PORT  
+    The port of the remote server. Required.
 
-*--bind, -b BIND-ADDR*:
-  The local address to bind to. You may need this if the remote server
-  is using an access control list.
+  --from, -F OFFSET  
+    The byte offset to start reading from. Required.  Maximum 2^62.
 
-write
-~~~~~
+  --size, -S SIZE  
+    The number of bytes to read. Required. Maximum 2^30.
 
-  $ cat ... | flexnbd write --addr <ADDR> --port <PORT> --from <OFFSET> 
-    --size <SIZE>  [--bind BIND-ADDR] [global option]*
+  --bind, -b BIND_ADDR  
+    The local address to bind to. You may need this if the remote
+    server is using an access control list.
+
+WRITE MODE
 
 Connect to the server at ADDR:PORT, and write SIZE bytes from STDIN
-starting at OFFSET in a single NBD query.  In case of a remote ACL, set
-the local source address to BIND-ADDR.
+starting at OFFSET in a single NBD query.
 
-Options
-^^^^^^^
+  $ cat ... | flexnbd write --addr ADDR --port PORT --from OFFSET
+      --size SIZE  [--bind BIND_ADDR] [global_option]*
 
-*--addr, -l ADDR*:
-  The address of the remote server.  Required.
+In case of a remote ACL, set the local source address to BIND_ADDR.
 
-*--port, -p PORT*:
-  The port of the remote server.  Required.
+  OPTIONS
 
-*--from, -F OFFSET*:
-  The byte offset to start writing from. Required. Maximum 2^62.
+  --addr, -l ADDR  
+    The address of the remote server. Required.
 
-*--size, -S SIZE*:
-  The number of bytes to write. Required.  Maximum 2^30.
+  --port, -p PORT  
+    The port of the remote server. Required.
 
-*--bind, -b BIND-ADDR*:
-  The local address to bind to. You may need this if the remote server
-  is using an access control list.
+  --from, -F OFFSET  
+    The byte offset to start writing from. Required.  Maximum 2^62.
 
-help
-~~~~
+  --size, -S SIZE  
+    The number of bytes to write. Required. Maximum 2^30.
 
-  $ flexnbd help [command] [global option]*
+  --bind, -b BIND_ADDR  
+    The local address to bind to. You may need this if the remote
+    server is using an access control list.
 
-Without 'command', show the list of available commands.  With 'command',
-show help for that command.
+HELP MODE
+
+  $ flexnbd help [mode] [global_option]*
+
+Without mode, show the list of available modes. With mode, show help for that mode.
 
 GLOBAL OPTIONS
---------------
 
-*--help, -h* :
-    Show command or global help.
+--help, -h  Show mode or global help.
 
-*--verbose, -v* :
-    Output all available log information to STDERR.
-
-*--quiet, -q* :
-    Output as little log information as possible to STDERR.
+--verbose, -v  Output all available log information to STDERR.
 
+--quiet, -q  Output as little log information as possible to STDERR.
 
 LOGGING
--------
-Log output is sent to STDERR.  If --quiet is set, no output will be seen
-unless the program termintes abnormally.  If neither --quiet nor
+
+Log output is sent to STDERR. If --quiet is set, no output will be
+seen unless the program termintes abnormally. If neither --quiet nor
 --verbose are set, no output will be seen unless something goes wrong
-with a specific request.  If --verbose is given, every available log
-message will be seen (which, for a debug build, is many).  It is not an
-error to set both --verbose and --quiet.  The last one wins.
+with a specific request. If --verbose is given, every available log
+message will be seen (which, for a debug build, is many). It is not an
+error to set both --verbose and --quiet. The last one wins.
 
 The log line format is:
 
-  <LEVEL>:<PID> <THREAD> <SOURCEFILE>:<SOURCELINE>: <MSG>
+  <TIMESTAMP>:<LEVEL>:<PID> <THREAD> <SOURCEFILE:SOURCELINE>: <MSG>
 
-*LEVEL*:
+<TIMESTAMP>  
+  Time the log entry was made. This is expressed in terms of monotonic
+  ms.
+
+<LEVEL>  
   This will be one of 'D', 'I', 'W', 'E', 'F' in increasing order of
-severity.  If flexnbd is started with the --quiet flag, only 'F' will be
-seen.  If it is started with the --verbose flag, any from 'I' upwards
-will be seen.  Only if you have a debug build and start it with
---verbose will you see 'D' entries.
+  severity. If flexnbd is started with the --quiet flag, only 'F'
+  will be seen. If it is started with the --verbose flag, any from 'I'
+  upwards will be seen. Only if you have a debug build and start it
+  with --verbose will you see 'D' entries.
 
-*PID*:
+<PID>  
   This is the process ID.
 
-*THREAD*:
-  There are several pthreads per flexnbd process: a main thread, a serve
-thread, a thread per client, and possibly a pair of mirror threads and a
-control thread.  This field identifies which thread was responsible for
-the log line.
+<THREAD>  
+  There are several pthreads per flexnbd process: a main thread, a
+  serve thread, a thread per client, and possibly a pair of mirror
+  threads and a control thread. This field identifies which thread was
+  responsible for the log line.
 
-*SOURCEFILE:SOURCELINE*:
+<SOURCEFILE:SOURCELINE>  
   Identifies where in the source code this log line can be found.
 
-*MSG*: 
+<MSG>  
   A short message describing what's happening, how it's being done, or
-if you're very lucky *why* it's going on.  
+  if you're very lucky why it's going on.
 
 EXAMPLES
---------
 
-Serving a file
-~~~~~~~~~~~~~~
+  SERVING A FILE
 
 The simplest case is serving a file on the default nbd port:
 
@@ -297,26 +331,24 @@ The simplest case is serving a file on the default nbd port:
   root:x:
   $
 
-Reading server status
-~~~~~~~~~~~~~~~~~~~~~
+  READING SERVER STATUS
 
 In order to read a server's status, we need it to open a control socket.
 
   $ flexnbd serve --file /tmp/passwd --addr 0.0.0.0 --port 4777 \
     --sock /tmp/flexnbd.sock
   $ flexnbd status --sock /tmp/flexnbd.sock
-  is_mirroring=false has_control=true
-
+  pid=9635 is_mirroring=false has_control=true
+  
   $
 
 Note that the status output is newline-terminated.
 
-Migrating
-~~~~~~~~~
+  MIGRATING
 
 To migrate, we need to provide a destination file of the right size.
 
-  $ dd if=/dev/random of=/tmp/data bs=1M count=1
+  $ dd if=/dev/urandom of=/tmp/data bs=1024 count=1K
   $ truncate -s 1M /tmp/data.copy
   $ flexnbd serve --file /tmp/data --addr 0.0.0.0 --port 4778 \
       --sock /tmp/flex-source.sock &
@@ -326,11 +358,11 @@ To migrate, we need to provide a destination file of the right size.
 
 Now we check the status of each server, to check that they are both in
 the right state:
- 
+
   $ flexnbd status --sock /tmp/flex-source.sock
-  is_mirroring=false has_control=true
+  pid=9648 is_mirroring=false has_control=true
   $ flexnbd status --sock /tmp/flex-dest.sock
-  is_mirroring=false has_control=false 
+  pid=9651 is_mirroring=false has_control=false
   $
 
 With this knowledge in hand, we can start the migration:
@@ -338,33 +370,34 @@ With this knowledge in hand, we can start the migration:
   $ flexnbd mirror --addr 127.0.0.1 --port 4779 \
       --sock /tmp/flex-source.sock
   Migration started
-  [1]  + 9648 done       build/flexnbd serve --addr 0.0.0.0 --port 4778
+  [1]  + 9648 done       flexnbd serve --addr 0.0.0.0 --port 4778
+  [2]  + 9651 done       flexnbd listen --addr 0.0.0.0 --port 4779
   $
 
 Note that because the file is so small in this case, we see the source
-server quit soon after we start the migration.
-
-We can check the status of the destination server, to ensure that it
-took control:
-
-  $ flexnbd status --sock /tmp/flex-dest.sock
-  is_mirroring=false has_control=true
+server quit soon after we start the migration, and the destination
+exited at roughly the same time.
 
 BUGS
-----
 
-Should be reported to alex@bytemark.co.uk.
+Should be reported on GitHub at
+
+ * https://github.com/BytemarkHosting/flexnbd-c/issues
 
 AUTHOR
-------
 
-Written by Alex Young <alex@bytemark.co.uk>.  
-Original concept and core code by Matthew Bloch
-<matthew@bytemark.co.uk>.
+Originally written by Alex Young <alex@blackkettle.org>.
+Original concept and core code by Matthew Bloch <matthew@bytemark.co.uk>.
+Proxy mode written by Nick Thomas <me@ur.gs>.
 
-COPYING
--------
+The full commit history is available on GitHub.
 
-Copyright (c) 2012 Bytemark Hosting Ltd. Free use of this software is
-granted under the terms of the GNU General Public License version 3 or
-later.
+SEE ALSO
+
+flexnbd-proxy(1), nbd-client(8), xnbd-server(8), xnbd-client(8)
+
+COPYRIGHT
+
+Copyright (c) 2012-2016 Bytemark Hosting Ltd. Free use of this
+software is granted under the terms of the GNU General Public License
+version 3 or later.

Rakefile

@@ -1,274 +0,0 @@
-$: << '../rake_utils/lib'
-require 'rake_utils/debian'
-include RakeUtils::DSL
-
-CC=ENV['CC'] || "gcc"
-
-DEBUG  = ENV.has_key?('DEBUG') &&
-  %w|yes y ok 1 true t|.include?(ENV['DEBUG'])
-
-ALL_SOURCES =FileList['src/*']
-SOURCES = ALL_SOURCES.select { |c| c =~ /\.c$/ }
-OBJECTS = SOURCES.pathmap( "%{^src,build}X.o" )
-TEST_SOURCES = FileList['tests/unit/*.c']
-TEST_OBJECTS = TEST_SOURCES.pathmap( "%{^tests/unit,build/tests}X.o" )
-
-LIBS    = %w( pthread )
-CCFLAGS = %w(
-             -D_GNU_SOURCE=1
-             -Wall
-             -Wextra
-             -Werror-implicit-function-declaration
-             -Wstrict-prototypes
-             -Wno-missing-field-initializers
-            ) + # Added -Wno-missing-field-initializers to shut GCC up over {0} struct initialisers
-            [ENV['CFLAGS']]
-LDFLAGS = []
-LIBCHECK = "/usr/lib/libcheck.a"
-
-TEST_MODULES = Dir["tests/unit/check_*.c"].map { |n|
-  File.basename( n )[%r{check_(.+)\.c},1] }
-
-if DEBUG
-  LDFLAGS << ["-g"]
-  CCFLAGS << ["-g -DDEBUG"]
-end
-
-desc "Build the binary and man page"
-task :build => ['build/flexnbd', 'build/flexnbd.1.gz']
-task :default => :build
-
-desc "Build just the binary"
-task :flexnbd => "build/flexnbd"
-
-def check(m)
-  "build/tests/check_#{m}"
-end
-
-file "README.txt"
-
-file "build/flexnbd.1.gz" => "README.txt" do
-  FileUtils.mkdir_p( "build" )
-  sh "a2x --destination-dir build --format manpage README.txt"
-  sh "gzip build/flexnbd.1"
-end
-
-desc "Build just the man page"
-task :man => "build/flexnbd.1.gz"
-
-
-namespace "test" do
-  desc "Run all tests"
-  task 'run' => ["unit", "scenarios"]
-
-  desc "Build C tests"
-  task 'build' => TEST_MODULES.map { |n| check n}
-
-  TEST_MODULES.each do |m|
-    desc "Run tests for #{m}"
-    task "check_#{m}" => check(m) do
-      sh check m
-    end
-  end
-
-  desc "Run C tests"
-  task 'unit' => 'build' do
-    TEST_MODULES.each do |n|
-      ENV['EF_DISABLE_BANNER'] = '1'
-      sh check n
-    end
-  end
-
-  desc "Run NBD test scenarios"
-  task 'scenarios' => 'flexnbd' do
-    sh "cd tests/acceptance; ruby nbd_scenarios"
-  end
-end
-
-
-
-def gcc_compile( target, source )
-  FileUtils.mkdir_p File.dirname( target )
-  sh "#{CC} -Isrc -c #{CCFLAGS.join(' ')} -o #{target} #{source} "
-end
-
-def gcc_link(target, objects)
-  FileUtils.mkdir_p File.dirname( target )
-
-  sh "#{CC} #{LDFLAGS.join(' ')} "+
-    LIBS.map { |l| "-l#{l}" }.join(" ")+
-    " -Isrc " +
-    " -o #{target} "+
-    objects.join(" ")
-end
-
-def headers(c)
-  `#{CC} -Isrc -MM #{c}`.gsub("\\\n", " ").split(" ")[2..-1]
-end
-
-rule 'build/flexnbd' => OBJECTS do |t|
-  gcc_link(t.name, t.sources)
-end
-
-
-file check("client") =>
-%w{build/tests/check_client.o
-  build/self_pipe.o
-  build/nbdtypes.o
-  build/listen.o
-  build/flexnbd.o
-  build/flexthread.o
-  build/control.o
-  build/readwrite.o
-  build/parse.o
-  build/client.o
-  build/serve.o
-  build/acl.o
-  build/ioutil.o
-  build/mbox.o
-  build/mirror.o
-  build/status.o
-  build/util.o} do |t|
-  gcc_link t.name, t.prerequisites + [LIBCHECK]
-end
-
-file check("acl") =>
-%w{build/tests/check_acl.o
-  build/parse.o
-  build/acl.o
-  build/util.o} do |t|
-  gcc_link t.name, t.prerequisites + [LIBCHECK]
-end
-
-file check( "util" ) =>
-%w{build/tests/check_util.o
-  build/util.o
-  build/self_pipe.o} do |t|
-  gcc_link t.name, t.prerequisites + [LIBCHECK]
-end
-
-file check("serve") =>
-%w{build/tests/check_serve.o
-  build/self_pipe.o
-  build/nbdtypes.o
-  build/control.o
-  build/readwrite.o
-  build/parse.o
-  build/client.o
-  build/flexthread.o
-  build/serve.o
-  build/flexnbd.o
-  build/mirror.o
-  build/status.o
-  build/listen.o
-  build/acl.o
-  build/mbox.o
-  build/ioutil.o
-  build/util.o} do |t|
-  gcc_link t.name, t.prerequisites + [LIBCHECK]
-end
-
-file check("readwrite") =>
-%w{build/tests/check_readwrite.o
-  build/readwrite.o
-  build/client.o
-  build/self_pipe.o
-  build/serve.o
-  build/parse.o
-  build/acl.o
-  build/flexthread.o
-  build/control.o
-  build/flexnbd.o
-  build/mirror.o
-  build/status.o
-  build/listen.o
-  build/nbdtypes.o
-  build/mbox.o
-  build/ioutil.o
-  build/util.o} do |t|
-  gcc_link t.name, t.prerequisites + [LIBCHECK]
-end
-
-file check("listen") =>
-%w{build/tests/check_listen.o
-  build/listen.o
-  build/flexnbd.o
-  build/status.o
-  build/flexthread.o
-  build/mbox.o
-  build/mirror.o
-  build/self_pipe.o
-  build/nbdtypes.o
-  build/control.o
-  build/readwrite.o
-  build/parse.o
-  build/client.o
-  build/serve.o
-  build/acl.o
-  build/ioutil.o
-  build/util.o} do |t|
-  gcc_link t.name, t.prerequisites + [LIBCHECK]
-end
-
-file check("flexnbd") =>
-%w{build/tests/check_flexnbd.o
-  build/flexnbd.o
-  build/ioutil.o
-  build/util.o
-  build/control.o
-  build/listen.o
-  build/mbox.o
-  build/flexthread.o
-  build/status.o
-  build/self_pipe.o
-  build/client.o
-  build/acl.o
-  build/parse.o
-  build/nbdtypes.o
-  build/readwrite.o
-  build/mirror.o
-  build/serve.o} do |t|
-  gcc_link t.name, t.prerequisites + [LIBCHECK]
-end
-
-file check("control") =>
-  %w{build/tests/check_control.o} + OBJECTS - ["build/main.o"] do |t|
-  gcc_link t.name, t.prerequisites + [LIBCHECK]
-end
-
-(TEST_MODULES- %w{control flexnbd acl client serve readwrite listen util}).each do |m|
-  tgt = "build/tests/check_#{m}.o"
-  maybe_obj_name = "build/#{m}.o"
-  # Take it out in case we're testing util.o or ioutil.o
-  deps = ["build/ioutil.o", "build/util.o"] - [maybe_obj_name]
-
-  # Add it back in if it's something we need to compile
-  deps << maybe_obj_name if OBJECTS.include?( maybe_obj_name )
-
-  file check( m ) => deps + [tgt] do |t|
-    gcc_link(t.name, deps + [tgt, LIBCHECK])
-  end
-end
-
-
-OBJECTS.zip( SOURCES ).each do |o,c|
-  file o => [c]+headers(c) do |t| gcc_compile( o, c ) end
-end
-
-TEST_OBJECTS.zip( TEST_SOURCES ).each do |o,c|
-  file o => [c] + headers(c) do |t| gcc_compile( o, c ) end
-end
-
-desc "Remove all build targets, binaries and temporary files"
-task :clean do
-  sh "rm -rf *~ build"
-end
-
-namespace :pkg do
-  deb do |t|
-    t.code_files = ALL_SOURCES + ["Rakefile", "README.txt"]
-    t.pkg_name = "flexnbd"
-    t.generate_changelog!
-  end
-end
-

debian/control

@@ -1,14 +1,25 @@
 Source: flexnbd
-Section: unknown
+Section: web
 Priority: extra
-Maintainer: Alex Young <alex@bytemark.co.uk>
-Build-Depends: cdbs, debhelper (>= 7), ruby, rake, gcc
+Maintainer: Patrick J Cherry <patrick@bytemark.co.uk> 
+Build-Depends: debhelper (>= 7.0.50), ruby, gcc, libev-dev, txt2man, check, net-tools, libsubunit-dev, ruby-test-unit
 Standards-Version: 3.8.1
-Homepage: http://bigv.io/
+Homepage: https://github.com/BytemarkHosting/flexnbd-c
 
 Package: flexnbd
 Architecture: any
-Depends: ${shlibs:Depends}, ${misc:Depends}
+Depends: ${shlibs:Depends}, ${misc:Depends}, libev4 | libev3
 Description: FlexNBD server
   An NBD server offering push-mirroring and intelligent sparse file handling
 
+Package: flexnbd-dbg
+Architecture: any
+Section: debug
+Priority: extra
+Depends:
+    flexnbd (= ${binary:Version}),
+    ${misc:Depends}
+Description: debugging symbols for flexnbd
+ An NBD server offering push-mirroring and intelligent sparse file handling
+ .
+ This package contains the debugging symbols for flexnbd.

debian/flexnbd.install

@@ -1,2 +1,3 @@
-build/flexnbd      usr/bin
-build/flexnbd.1.gz usr/share/man/man1
+build/flexnbd             usr/bin
+build/flexnbd-proxy       usr/bin
+

debian/flexnbd.manpages

@@ -0,0 +1,2 @@
+build/flexnbd.1.gz
+build/flexnbd-proxy.1.gz

debian/rules

@@ -7,8 +7,13 @@
 %:
 	dh $@ 
 
-override_dh_auto_build:
-	rake build
+override_dh_strip:
+	dh_strip --dbg-package=flexnbd-dbg
+
+#
+# TODO: The ruby test suites don't work during buiding in a chroot, so leave
+# them out for now.
+#
+#override_dh_auto_test:
+#	rake test:run
 
-override_dh_auto_clean:
-	rake clean

src/bitset.h

@@ -1,194 +0,0 @@
-#ifndef BITSET_H
-#define BITSET_H
-
-#include "util.h"
-
-#include <inttypes.h>
-#include <string.h>
-#include <pthread.h>
-
-
-static inline char char_with_bit_set(int num) { return 1<<(num%8); }
-
-/** Return 1 if the bit at ''idx'' in array ''b'' is set */
-static inline int bit_is_set(char* b, int idx) {
-	return (b[idx/8] & char_with_bit_set(idx)) != 0;
-}
-/** Return 1 if the bit at ''idx'' in array ''b'' is clear */
-static inline int bit_is_clear(char* b, int idx) {
-	return !bit_is_set(b, idx);
-}
-/** Tests whether the bit at ''idx'' in array ''b'' has value ''value'' */
-static inline int bit_has_value(char* b, int idx, int value) {
-	if (value) { return bit_is_set(b, idx); }
-	else { return bit_is_clear(b, idx); }
-}
-/** Sets the bit ''idx'' in array ''b'' */
-static inline void bit_set(char* b, int idx) {
-	b[idx/8] |= char_with_bit_set(idx);
-	//__sync_fetch_and_or(b+(idx/8), char_with_bit_set(idx));
-}
-/** Clears the bit ''idx'' in array ''b'' */
-static inline void bit_clear(char* b, int idx) {
-	b[idx/8] &= ~char_with_bit_set(idx);
-	//__sync_fetch_and_nand(b+(idx/8), char_with_bit_set(idx));
-}
-/** Sets ''len'' bits in array ''b'' starting at offset ''from'' */
-static inline void bit_set_range(char* b, int from, int len) {
-	for (; from%8 != 0 && len > 0; len--) { bit_set(b, from++); }
-	if (len >= 8) { memset(b+(from/8), 255, len/8); }
-	for (; len > 0; len--) { bit_set(b, from++); }
-}
-/** Clears ''len'' bits in array ''b'' starting at offset ''from'' */
-static inline void bit_clear_range(char* b, int from, int len) {
-	for (; from%8 != 0 && len > 0; len--) {	bit_clear(b, from++); }
-	if (len >= 8) { memset(b+(from/8), 0, len/8); }
-	for (; len > 0; len--) { bit_clear(b, from++); }
-}
-
-/** Counts the number of contiguous bits in array ''b'', starting at ''from'' 
-  * up to a maximum number of bits ''len''.  Returns the number of contiguous
-  * bits that are the same as the first one specified.
-  */
-static inline int bit_run_count(char* b, int from, int len) {
-	int count;
-	int first_value = bit_is_set(b, from);
-
-	for (count=0; len > 0 && bit_has_value(b, from+count, first_value); count++, len--)
-		;
-
-	/* FIXME: debug this later */
-	/*for (; (from+count) % 64 != 0 && len > 0; len--)
-		if (bit_has_value(b, from+count, first_value))
-			count++;
-		else
-			return count;
-	for (; len >= 64; len-=64) {
-		if (*((uint64_t*)(b + ((from+count)/8))) == UINT64_MAX)
-			count += 64;
-		else
-			break;
-	}
-	for (; len > 0; len--)
-		if (bit_is_set(b, from+count))
-			count++;*/
-
-	return count;
-}
-
-/** An application of a bitset - a bitset mapping represents a file of ''size'' 
-  * broken down into ''resolution''-sized chunks.  The bit set is assumed to
-  * represent one bit per chunk.
-  */
-struct bitset_mapping {
-	uint64_t size;
-	int resolution;
-	char bits[];
-};
-
-/** Allocate a bitset_mapping for a file of the given size, and chunks of the
-  * given resolution.
-  */
-static inline struct bitset_mapping* bitset_alloc(
-	uint64_t size, 
-	int resolution
-)
-{
-	struct bitset_mapping *bitset = xmalloc(
-		sizeof(struct bitset_mapping)+
-		(size+resolution-1)/resolution
-	);
-	bitset->size = size;
-	bitset->resolution = resolution;
-	return bitset;
-}
-
-#define INT_FIRST_AND_LAST \
-  int first = from/set->resolution, \
-      last = (from+len-1)/set->resolution, \
-      bitlen = last-first+1
-
-/** Set the bits in a bitset which correspond to the given bytes in the larger
-  * file.
-  */
-static inline void bitset_set_range(
-	struct bitset_mapping* set, 
-	uint64_t from, 
-	uint64_t len)
-{
-	INT_FIRST_AND_LAST;
-	bit_set_range(set->bits, first, bitlen);
-}
-
-
-/** Set every bit in the bitset. */
-static inline void bitset_set(
-	struct bitset_mapping* set
-)
-{
-	bitset_set_range(set, 0, set->size);
-}
-
-
-
-/** Clear the bits in a bitset which correspond to the given bytes in the 
-  * larger file.
-  */
-static inline void bitset_clear_range(
-	struct bitset_mapping* set, 
-	uint64_t from, 
-	uint64_t len)
-{
-	INT_FIRST_AND_LAST;
-	bit_clear_range(set->bits, first, bitlen);
-}
-
-
-/** Clear every bit in the bitset. */
-static inline void bitset_clear(
-		struct bitset_mapping *set
-)
-{
-	bitset_clear_range(set, 0, set->size);
-}
-
-
-/** Counts the number of contiguous bytes that are represented as a run in
-  * the bit field.
-  */
-static inline int bitset_run_count(
-	struct bitset_mapping* set, 
-	uint64_t from, 
-	uint64_t len)
-{
-	/* now fix in case len goes past the end of the memory we have
-	 * control of */
-	len = len+from>set->size ? set->size-from : len;
-	INT_FIRST_AND_LAST;
-	return (bit_run_count(set->bits, first, bitlen) * set->resolution) -
-	  (from % set->resolution);
-}
-
-/** Tests whether the bit field is clear for the given file offset.
-  */
-static inline int bitset_is_clear_at(
-	struct bitset_mapping* set,
-	uint64_t at
-)
-{
-	return bit_is_clear(set->bits, at/set->resolution);
-}
-
-/** Tests whether the bit field is set for the given file offset.
-  */
-static inline int bitset_is_set_at(
-	struct bitset_mapping* set,
-	uint64_t at
-)
-{
-	return bit_is_set(set->bits, at/set->resolution);
-}
-
-
-#endif
-

src/common/ioutil.c

@@ -0,0 +1,383 @@
+#include <sys/mman.h>
+#include <sys/sendfile.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <linux/fs.h>
+#include <linux/fiemap.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "util.h"
+#include "bitset.h"
+#include "ioutil.h"
+
+
+int build_allocation_map(struct bitset * allocation_map, int fd)
+{
+	/* break blocking ioctls down */
+	const unsigned long max_length  = 100*1024*1024;
+	const unsigned int  max_extents = 1000;
+
+	unsigned long offset = 0;
+
+	struct {
+		struct fiemap fiemap;
+		struct fiemap_extent extents[max_extents];
+	} fiemap_static;
+	struct fiemap* fiemap = (struct fiemap*) &fiemap_static;
+
+	memset(&fiemap_static, 0, sizeof(fiemap_static));
+
+	for (offset = 0; offset < allocation_map->size; ) {
+
+		fiemap->fm_start = offset;
+
+		fiemap->fm_length = max_length;
+		if ( offset + max_length > allocation_map->size ) {
+			fiemap->fm_length = allocation_map->size-offset;
+		}
+
+		fiemap->fm_flags = FIEMAP_FLAG_SYNC;
+		fiemap->fm_extent_count = max_extents;
+		fiemap->fm_mapped_extents = 0;
+
+		if ( ioctl( fd, FS_IOC_FIEMAP, fiemap ) < 0 ) {
+			debug( "Couldn't get fiemap, returning no allocation_map" );
+			return 0; /* it's up to the caller to free the map */
+		}
+		else {
+			for ( unsigned int i = 0; i < fiemap->fm_mapped_extents; i++ ) {
+				bitset_set_range( allocation_map,
+						  fiemap->fm_extents[i].fe_logical,
+						  fiemap->fm_extents[i].fe_length );
+			}
+
+
+			/* must move the offset on, but careful not to jump max_length
+			 * if we've actually hit max_offsets.
+			 */
+			if (fiemap->fm_mapped_extents > 0) {
+				struct fiemap_extent *last = &fiemap->fm_extents[
+					fiemap->fm_mapped_extents-1
+				];
+				offset = last->fe_logical + last->fe_length;
+			}
+			else {
+				offset += fiemap->fm_length;
+			}
+		}
+	}
+
+	info("Successfully built allocation map");
+	return 1;
+}
+
+int open_and_mmap(const char* filename, int* out_fd, uint64_t *out_size, void **out_map)
+{
+	/* 
+	 * size and out_size are intentionally of different types.
+	 * lseek64() uses off64_t to signal errors in the sign bit.
+	 * Since we check for these errors before trying to assign to
+	 * *out_size, we know *out_size can never go negative.
+	 */
+	off64_t size;
+
+	/* O_DIRECT should not be used with mmap() */
+	*out_fd = open(filename, O_RDWR | O_SYNC );
+
+	if (*out_fd < 1) {
+		warn("open(%s) failed: does it exist?", filename);
+		return *out_fd;
+	}
+
+	size = lseek64(*out_fd, 0, SEEK_END);
+	if (size < 0) {
+		warn("lseek64() failed");
+		return size;
+	}
+	if (out_size) {
+		*out_size = size;
+	}
+
+	if (0) {
+		*out_map = mmap64(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED,
+		  *out_fd, 0);
+		if (((long) *out_map) == -1) {
+			warn("mmap64() failed");
+			return -1;
+		}
+		debug("opened %s size %ld on fd %d @ %p", filename, size, *out_fd, *out_map);
+	}
+	else {
+		debug("opened %s size %ld on fd %d", filename, size, *out_fd);
+	}
+
+	return 0;
+}
+
+
+int writeloop(int filedes, const void *buffer, size_t size)
+{
+	size_t written=0;
+	while (written < size) {
+		ssize_t result = write(filedes, buffer+written, size-written);
+		if (result == -1) {
+			if ( errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK ) {
+				continue; // busy-wait
+			}
+			return -1; // failure
+		}
+		written += result;
+	}
+	return 0;
+}
+
+int readloop(int filedes, void *buffer, size_t size)
+{
+	size_t readden=0;
+	while (readden < size) {
+		ssize_t result = read(filedes, buffer+readden, size-readden);
+
+		if ( result == 0 /* EOF */ ) {
+			warn( "end-of-file detected while reading after %i bytes", readden );
+			return -1;
+		}
+
+		if ( result == -1 ) {
+			if ( errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK ) {
+				continue; // busy-wait
+			}
+			return -1; // failure
+		}
+		readden += result;
+	}
+	return 0;
+}
+
+int sendfileloop(int out_fd, int in_fd, off64_t *offset, size_t count)
+{
+	size_t sent=0;
+	while (sent < count) {
+		ssize_t result = sendfile64(out_fd, in_fd, offset, count-sent);
+		debug("sendfile64(out_fd=%d, in_fd=%d, offset=%p, count-sent=%ld) = %ld", out_fd, in_fd, offset, count-sent, result);
+
+		if (result == -1) {
+			debug( "%s (%i) calling sendfile64()", strerror(errno), errno );
+			return -1;
+		}
+		sent += result;
+		debug("sent=%ld, count=%ld", sent, count);
+	}
+	debug("exiting sendfileloop");
+	return 0;
+}
+
+#include <errno.h>
+ssize_t spliceloop(int fd_in, loff_t *off_in, int fd_out, loff_t *off_out, size_t len, unsigned int flags2)
+{
+	const unsigned int flags = SPLICE_F_MORE|SPLICE_F_MOVE|flags2;
+	size_t spliced=0;
+
+	//debug("spliceloop(%d, %ld, %d, %ld, %ld)", fd_in, off_in ? *off_in : 0, fd_out, off_out ? *off_out : 0, len);
+
+	while (spliced < len) {
+		ssize_t result = splice(fd_in, off_in, fd_out, off_out, len, flags);
+		if (result < 0) {
+			//debug("result=%ld (%s), spliced=%ld, len=%ld", result, strerror(errno), spliced, len);
+			if (errno == EAGAIN && (flags & SPLICE_F_NONBLOCK) ) {
+				return spliced;
+			}
+			else {
+				return -1;
+			}
+		} else {
+			spliced += result;
+			//debug("result=%ld (%s), spliced=%ld, len=%ld", result, strerror(errno), spliced, len);
+		}
+	}
+
+	return spliced;
+}
+
+int splice_via_pipe_loop(int fd_in, int fd_out, size_t len)
+{
+
+	int pipefd[2]; /* read end, write end */
+	size_t spliced=0;
+
+	if (pipe(pipefd) == -1) {
+		return -1;
+	}
+
+	while (spliced < len) {
+		ssize_t run = len-spliced;
+		ssize_t s2, s1 = spliceloop(fd_in, NULL, pipefd[1], NULL, run, SPLICE_F_NONBLOCK);
+		/*if (run > 65535)
+			run = 65535;*/
+		if (s1 < 0) { break; }
+
+		s2 = spliceloop(pipefd[0], NULL, fd_out, NULL, s1, 0);
+		if (s2 < 0) { break; }
+		spliced += s2;
+	}
+	close(pipefd[0]);
+	close(pipefd[1]);
+
+	return spliced < len ? -1 : 0;
+}
+
+/* Reads single bytes from fd until either an EOF or a newline appears.
+ * If an EOF occurs before a newline, returns -1.  The line is lost.
+ * Inserts the read bytes (without the newline) into buf, followed by a
+ * trailing NULL.
+ * Returns the number of read bytes: the length of the line without the
+ * newline, plus the trailing null.
+ */
+int read_until_newline(int fd, char* buf, int bufsize)
+{
+	int cur;
+
+	for (cur=0; cur < bufsize; cur++) {
+		int result = read(fd, buf+cur, 1);
+		if (result <= 0) { return -1; }
+		if (buf[cur] == 10) {
+			buf[cur] = '\0';
+			break;
+		}
+	}
+
+	return cur+1;
+}
+
+int read_lines_until_blankline(int fd, int max_line_length, char ***lines)
+{
+	int lines_count = 0;
+	char line[max_line_length+1];
+	*lines = NULL;
+
+	memset(line, 0, max_line_length+1);
+
+	while (1) {
+		int readden = read_until_newline(fd, line, max_line_length);
+		/* readden will be:
+		 * 1 for an empty line
+		 * -1 for an eof
+		 * -1 for a read error
+		 */
+		if (readden <= 1) { return lines_count; }
+		*lines = xrealloc(*lines, (lines_count+1) * sizeof(char*));
+		(*lines)[lines_count] = strdup(line);
+		if ((*lines)[lines_count][0] == 0) {
+			return lines_count;
+		}
+		lines_count++;
+	}
+}
+
+
+int fd_is_closed( int fd_in )
+{
+	int errno_old = errno;
+	int result = fcntl( fd_in, F_GETFL ) < 0;
+	errno = errno_old;
+	return result;
+}
+
+
+static inline int io_errno_permanent(void)
+{
+	return ( errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR );
+}
+
+
+/* Returns -1 if the operation failed, or the number of bytes read if all is
+ * well. Note that 0 bytes may be returned. Unlike read(), this is not an EOF! */
+ssize_t iobuf_read(int fd, struct iobuf *iobuf, size_t default_size )
+{
+	size_t left;
+	ssize_t count;
+
+	if ( iobuf->needle == 0 ) {
+		iobuf->size = default_size;
+	}
+
+	left = iobuf->size - iobuf->needle;
+	debug( "Reading %"PRIu32" of %"PRIu32" bytes from fd %i", left, iobuf->size, fd );
+
+	count = read( fd, iobuf->buf + iobuf->needle, left );
+
+	if ( count > 0 ) {
+		iobuf->needle += count;
+		debug( "read() returned %"PRIu32" bytes", count );
+	} else if ( count == 0 ) {
+		warn( "read() returned EOF on fd %i", fd );
+		errno = 0;
+		return -1;
+	} else if ( count == -1 ) {
+		if ( io_errno_permanent() ) {
+			warn( SHOW_ERRNO( "read() failed on fd %i", fd ) );
+		} else {
+			debug( SHOW_ERRNO( "read() returned 0 bytes" ) );
+			count = 0;
+		}
+	}
+
+	return count;
+}
+
+ssize_t iobuf_write( int fd, struct iobuf *iobuf )
+{
+	size_t left = iobuf->size - iobuf->needle;
+	ssize_t count;
+
+	debug( "Writing %"PRIu32" of %"PRIu32" bytes to fd %i", left, iobuf->size, fd );
+	count = write( fd, iobuf->buf + iobuf->needle, left );
+
+	if ( count >= 0 ) {
+		iobuf->needle += count;
+		debug( "write() returned %"PRIu32" bytes", count );
+	} else {
+		if ( io_errno_permanent() ) {
+			warn( SHOW_ERRNO( "write() failed on fd %i", fd ) );
+		} else {
+			debug( SHOW_ERRNO( "write() returned 0 bytes" ) );
+			count = 0;
+		}
+	}
+
+	return count;
+}
+
+struct iommap *iommap_alloc(int fd, off64_t from, uint64_t len) {
+
+	off66_t mmap_from = from & ~((off64_t) getpagesize() - 1);
+        uint64_t mmap_len = len + (from - mmap_from);
+        void *mmap_buf = NULL;
+
+	// TODO: Check the error code from mmap64
+	if(mmap_len)
+		mmap_buf = mmap64(NULL, mmap_len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, mmap_from);
+
+	struct iommap *im = xmalloc(sizeof(struct iommap ));
+
+	im->mmap_buf = mmap_buf;
+	im->mmap_len = mmap_len;
+	im->buf = (char *) mmap_buf + from - mmap_from;
+	debug("mmapped file from %ld:%d", mmap_from, mmap_len);
+	return im;
+}
+
+void iommap_sync(struct iommap *im) {
+        if (im->mmap_len)
+		msync(im->mmap_buf, im->mmap_len, MS_SYNC | MS_INVALIDATE);
+	return;
+}
+
+void iommap_free(struct iommap *im) {
+        if (im->mmap_len)
+		munmap(im->mmap_buf, im->mmap_len);
+
+	free(im);
+}
+

src/common/ioutil.h

@@ -1,16 +1,39 @@
 #ifndef __IOUTIL_H
 #define __IOUTIL_H
 
-#include "serve.h"
-struct bitset_mapping; /* don't need whole of bitset.h here */
+#include <sys/types.h>
+struct iobuf {
+	unsigned char *buf;
+	size_t size;
+	size_t needle;
+};
 
-/** Returns a bit field representing which blocks are allocated in file 
-  * descriptor ''fd''.  You must supply the size, and the resolution at which
-  * you want the bits to represent allocated blocks.  If the OS represents
-  * allocated blocks at a finer resolution than you've asked for, any block
-  * or part block will count as "allocated" with the corresponding bit set.
+ssize_t iobuf_read( int fd, struct iobuf* iobuf, size_t default_size );
+ssize_t iobuf_write( int fd, struct iobuf* iobuf );
+
+#include <inttypes.h>
+
+struct iommap {
+	char *buf;
+	char *mmap_buf;
+	uint64_t mmap_len;
+};
+
+struct iommap *iommap_alloc(int fd, off64_t from, uint64_t len);
+void   iommap_sync(struct iommap *im);
+void   iommap_free(struct iommap *im);
+
+#include "serve.h"
+
+struct bitset; /* don't need whole of bitset.h here */
+
+/** Scan the file opened in ''fd'', set bits in ''allocation_map''  that
+  * correspond to which blocks are physically allocated on disc (or part-
+  * allocated).  If the OS represents allocated blocks at a finer resolution
+  * than you've asked for, any block or part block will count as "allocated"
+  * with the corresponding bit set.  Returns 1 if successful, 0 otherwise.
   */
-struct bitset_mapping* build_allocation_map(int fd, off64_t size, int resolution);
+int build_allocation_map(struct bitset * allocation_map, int fd);
 
 /** Repeat a write() operation that succeeds partially until ''size'' bytes
   * are written, or an error is returned, when it returns -1 as usual.
@@ -43,19 +66,19 @@ int splice_via_pipe_loop(int fd_in, int fd_out, size_t len);
 int read_until_newline(int fd, char* buf, int bufsize);
 
 /** Read a number of lines using read_until_newline, until an empty line is
-  * received (i.e. the sequence LF LF).  The data is read from ''fd'' and 
+  * received (i.e. the sequence LF LF).  The data is read from ''fd'' and
   * lines must be a maximum of ''max_line_length''.  The set of lines is
   * returned as an array of zero-terminated strings; you must pass an address
   * ''lines'' in which you want the address of this array returned.
   */
 int read_lines_until_blankline(int fd, int max_line_length, char ***lines);
 
-/** Open the given ''filename'', determine its size, and mmap it in its 
-  * entirety.  The file descriptor is stored in ''out_fd'', the size in 
+/** Open the given ''filename'', determine its size, and mmap it in its
+  * entirety.  The file descriptor is stored in ''out_fd'', the size in
   * ''out_size'' and the address of the mmap in ''out_map''.  If anything goes
   * wrong, returns -1 setting errno, otherwise 0.
   */
-int open_and_mmap( const char* filename, int* out_fd, off64_t *out_size, void **out_map);
+int open_and_mmap( const char* filename, int* out_fd, uint64_t* out_size, void **out_map);
 
 
 /** Check to see whether the given file descriptor is closed.

src/common/mode.h

@@ -7,20 +7,25 @@ void mode(char* mode, int argc, char **argv);
 
 #include <getopt.h>
 
-#define GETOPT_ARG(x,s)  {(x), 1, 0, (s)}
-#define GETOPT_FLAG(x,v) {(x), 0, 0, (v)}
+#define GETOPT_ARG(x,s)    {(x), required_argument, 0, (s)}
+#define GETOPT_FLAG(x,v)   {(x), no_argument, 0, (v)}
+#define GETOPT_OPTARG(x,s) {(x), optional_argument, 0, (s)}
 
 #define OPT_HELP "help"
 #define OPT_ADDR "addr"
-#define OPT_REBIND_ADDR "rebind-addr"
 #define OPT_BIND "bind"
 #define OPT_PORT "port"
-#define OPT_REBIND_PORT "rebind-port"
 #define OPT_FILE "file"
 #define OPT_SOCK "sock"
 #define OPT_FROM "from"
 #define OPT_SIZE "size"
 #define OPT_DENY "default-deny"
+#define OPT_CACHE "cache"
+#define OPT_UNLINK "unlink"
+#define OPT_CONNECT_ADDR "conn-addr"
+#define OPT_CONNECT_PORT "conn-port"
+#define OPT_KILLSWITCH "killswitch"
+#define OPT_MAX_SPEED "max-speed"
 
 #define CMD_SERVE  "serve"
 #define CMD_LISTEN "listen"
@@ -28,9 +33,11 @@ void mode(char* mode, int argc, char **argv);
 #define CMD_WRITE  "write"
 #define CMD_ACL    "acl"
 #define CMD_MIRROR "mirror"
+#define CMD_MIRROR_SPEED "mirror-speed"
+#define CMD_BREAK  "break"
 #define CMD_STATUS "status"
 #define CMD_HELP   "help"
-#define LEN_CMD_MAX 7
+#define LEN_CMD_MAX 13
 
 #define PATH_LEN_MAX 1024
 #define ADDR_LEN_MAX 64
@@ -40,16 +47,19 @@ void mode(char* mode, int argc, char **argv);
 
 #define GETOPT_HELP GETOPT_FLAG( OPT_HELP, 'h' )
 #define GETOPT_DENY GETOPT_FLAG( OPT_DENY, 'd' )
-
 #define GETOPT_ADDR GETOPT_ARG( OPT_ADDR, 'l' )
-#define GETOPT_REBIND_ADDR GETOPT_ARG( OPT_REBIND_ADDR, 'L')
 #define GETOPT_PORT GETOPT_ARG( OPT_PORT, 'p' )
-#define GETOPT_REBIND_PORT GETOPT_ARG( OPT_REBIND_PORT, 'P')
 #define GETOPT_FILE GETOPT_ARG( OPT_FILE, 'f' )
 #define GETOPT_SOCK GETOPT_ARG( OPT_SOCK, 's' )
 #define GETOPT_FROM GETOPT_ARG( OPT_FROM, 'F' )
 #define GETOPT_SIZE GETOPT_ARG( OPT_SIZE, 'S' )
 #define GETOPT_BIND GETOPT_ARG( OPT_BIND, 'b' )
+#define GETOPT_CACHE GETOPT_OPTARG( OPT_CACHE, 'c' )
+#define GETOPT_UNLINK GETOPT_ARG( OPT_UNLINK, 'u' )
+#define GETOPT_CONNECT_ADDR GETOPT_ARG( OPT_CONNECT_ADDR, 'C' )
+#define GETOPT_CONNECT_PORT GETOPT_ARG( OPT_CONNECT_PORT, 'P' )
+#define GETOPT_KILLSWITCH   GETOPT_ARG( OPT_KILLSWITCH,   'k' )
+#define GETOPT_MAX_SPEED    GETOPT_ARG( OPT_MAX_SPEED, 'm' )
 
 #define OPT_VERBOSE "verbose"
 #define SOPT_VERBOSE "v"
@@ -63,6 +73,8 @@ void mode(char* mode, int argc, char **argv);
 # define VERBOSE_LOG_LEVEL 1
 #endif
 
+#define QUIET_LOG_LEVEL 4
+
 #define OPT_QUIET "quiet"
 #define SOPT_QUIET "q"
 #define GETOPT_QUIET GETOPT_FLAG( OPT_QUIET, 'q' )
@@ -76,8 +88,10 @@ void mode(char* mode, int argc, char **argv);
 	"\t--" OPT_SOCK  ",-s <SOCK>\tPath to the control socket.\n"
 #define BIND_LINE \
 	 "\t--" OPT_BIND ",-b <BIND-ADDR>\tBind the local socket to a particular IP address.\n"
-
+#define MAX_SPEED_LINE \
+	 "\t--" OPT_MAX_SPEED ",-m <bps>\tMaximum speed of the migration, in bytes/sec.\n"
 
 char * help_help_text;
 
 #endif
+

src/common/nbdtypes.c

@@ -27,7 +27,7 @@ void nbd_r2h_request( struct nbd_request_raw *from, struct nbd_request * to )
 {
 	to->magic = htobe32( from->magic );
 	to->type = htobe32( from->type );
-	memcpy( to->handle, from->handle, 8 );
+	to->handle.w = from->handle.w;
 	to->from = htobe64( from->from );
 	to->len = htobe32( from->len );
 }
@@ -36,7 +36,7 @@ void nbd_h2r_request( struct nbd_request * from, struct nbd_request_raw * to )
 {
 	to->magic = be32toh( from->magic );
 	to->type = be32toh( from->type );
-	memcpy( to->handle, from->handle, 8 );
+	to->handle.w = from->handle.w;
 	to->from = be64toh( from->from );
 	to->len = be32toh( from->len );
 }
@@ -46,12 +46,13 @@ void nbd_r2h_reply( struct nbd_reply_raw * from, struct nbd_reply * to )
 {
 	to->magic = htobe32( from->magic );
 	to->error = htobe32( from->error );
-	memcpy( to->handle, from->handle, 8 );
+	to->handle.w = from->handle.w;
 }
 
 void nbd_h2r_reply( struct nbd_reply * from, struct nbd_reply_raw * to )
 {
 	to->magic = be32toh( from->magic );
 	to->error = be32toh( from->error );
-	memcpy( to->handle, from->handle, 8 );
+	to->handle.w = from->handle.w;
 }
+

src/common/nbdtypes.h

@@ -3,18 +3,32 @@
 
 
 /* http://linux.derkeiler.com/Mailing-Lists/Kernel/2003-09/2332.html */
-#define INIT_PASSWD "NBDMAGIC" 
-#define INIT_MAGIC 0x0000420281861253 
-#define REQUEST_MAGIC 0x25609513 
-#define REPLY_MAGIC 0x67446698 
-#define REQUEST_READ 0 
-#define REQUEST_WRITE 1 
-#define REQUEST_DISCONNECT 2 
-#define REQUEST_ENTRUST (1<<16)
+#define INIT_PASSWD "NBDMAGIC"
+#define INIT_MAGIC 0x0000420281861253
+#define REQUEST_MAGIC 0x25609513
+#define REPLY_MAGIC 0x67446698
+#define REQUEST_READ 0
+#define REQUEST_WRITE 1
+#define REQUEST_DISCONNECT 2
+
+/* The top 2 bytes of the type field are overloaded and can contain flags */
+#define REQUEST_MASK 0x0000ffff
+
+
+/* 1MiB is the de-facto standard for maximum size of header + data */
+#define NBD_MAX_SIZE ( 32 * 1024 * 1024 )
+
+#define NBD_REQUEST_SIZE ( sizeof( struct nbd_request_raw ) )
+#define NBD_REPLY_SIZE   ( sizeof( struct nbd_reply_raw ) )
 
 #include <linux/types.h>
 #include <inttypes.h>
 
+typedef union nbd_handle_t {
+	uint8_t b[8];
+	uint64_t w;
+} nbd_handle_t;
+
 /* The _raw types are the types as they appear on the wire.  Non-_raw
  * types are in host-format.
  * Conversion functions are _r2h_ for converting raw to host, and _h2r_
@@ -30,7 +44,7 @@ struct nbd_init_raw {
 struct nbd_request_raw {
 	__be32 magic;
 	__be32 type;    /* == READ || == WRITE  */
-	char handle[8];
+	nbd_handle_t handle;
 	__be64 from;
 	__be32 len;
 } __attribute__((packed));
@@ -38,7 +52,7 @@ struct nbd_request_raw {
 struct nbd_reply_raw {
 	__be32 magic;
 	__be32 error;           /* 0 = ok, else error   */
-	char handle[8];         /* handle you got from request  */
+	nbd_handle_t handle;         /* handle you got from request  */
 };
 
 
@@ -52,8 +66,8 @@ struct nbd_init {
 
 struct nbd_request {
 	uint32_t magic;
-	uint32_t type;    /* == READ || == WRITE  */
-	char handle[8];
+	uint32_t type;    /* == READ || == WRITE || == DISCONNECT */
+	nbd_handle_t handle;
 	uint64_t from;
 	uint32_t len;
 } __attribute__((packed));
@@ -61,10 +75,9 @@ struct nbd_request {
 struct nbd_reply {
 	uint32_t magic;
 	uint32_t error;           /* 0 = ok, else error   */
-	char handle[8];         /* handle you got from request  */
+	nbd_handle_t handle;      /* handle you got from request  */
 };
 
-
 void nbd_r2h_init( struct nbd_init_raw * from, struct nbd_init * to );
 void nbd_r2h_request( struct nbd_request_raw *from, struct nbd_request * to );
 void nbd_r2h_reply( struct nbd_reply_raw * from, struct nbd_reply * to );

src/common/parse.c

@@ -8,6 +8,7 @@ int atoi(const char *nptr);
                               ((x) >= 'A' && (x) <= 'F' ) || \
                                (x) == ':' || (x) == '.'      \
                             )
+
 /* FIXME: should change this to return negative on error like everything else */
 int parse_ip_to_sockaddr(struct sockaddr* out, char* src)
 {
@@ -47,6 +48,22 @@ int parse_ip_to_sockaddr(struct sockaddr* out, char* src)
 	return 0;
 }
 
+
+int parse_to_sockaddr(struct sockaddr* out, char* address)
+{
+	struct sockaddr_un* un = (struct sockaddr_un*) out;
+
+	NULLCHECK( address );
+
+	if ( address[0] == '/' ) {
+		un->sun_family = AF_UNIX;
+		strncpy( un->sun_path, address, 108 ); /* FIXME: linux only */
+		return 1;
+	}
+
+	return parse_ip_to_sockaddr( out, address );
+}
+
 int parse_acl(struct ip_and_mask (**out)[], int max, char **entries)
 {
 	struct ip_and_mask* list;

src/common/parse.h

@@ -2,6 +2,8 @@
 #define PARSE_H
 
 #include <sys/socket.h>
+#include <sys/un.h>
+
 #include <arpa/inet.h>
 #include <unistd.h>
 
@@ -10,6 +12,7 @@ union mysockaddr {
 	struct sockaddr     generic;
         struct sockaddr_in  v4;
         struct sockaddr_in6 v6;
+        struct sockaddr_un  un;
 };
 
 struct ip_and_mask {
@@ -18,6 +21,7 @@ struct ip_and_mask {
 };
 
 int parse_ip_to_sockaddr(struct sockaddr* out, char* src);
+int parse_to_sockaddr(struct sockaddr* out, char* src);
 int parse_acl(struct ip_and_mask (**out)[], int max, char **entries);
 void parse_port( char *s_port, struct sockaddr_in *out );
 

src/common/readwrite.c

@@ -1,7 +1,8 @@
 #include "nbdtypes.h"
 #include "ioutil.h"
+#include "sockutil.h"
 #include "util.h"
-#include "serve.h" 
+#include "serve.h"
 
 #include <stdlib.h>
 #include <string.h>
@@ -16,52 +17,95 @@ int socket_connect(struct sockaddr* to, struct sockaddr* from)
 	}
 
 	if (NULL != from) {
-		if ( 0 > bind(fd, from, sizeof(struct sockaddr_in6)) ){
-			warn( "bind() failed");
-			close( fd );
+		if ( 0 > bind( fd, from, sizeof(struct sockaddr_in6 ) ) ){
+			warn( SHOW_ERRNO( "bind() to source address failed" ) );
+			if ( 0 > close( fd ) ) {  /* Non-fatal leak */
+				warn( SHOW_ERRNO( "Failed to close fd %i", fd ) );
+			}
 			return -1;
 		}
 	}
 
-	if ( 0 > connect(fd, to, sizeof(struct sockaddr_in6)) ) {
-		warn( "connect failed" );
-		close( fd );
+	if ( 0 > sock_try_connect( fd, to, sizeof( struct sockaddr_in6 ), 15 ) ) {
+		warn( SHOW_ERRNO( "connect failed" ) );
+		if ( 0 > close( fd ) ) { /* Non-fatal leak */
+			warn( SHOW_ERRNO( "Failed to close fd %i", fd ) );
+		}
 		return -1;
 	}
 
+	if ( sock_set_tcp_nodelay( fd, 1 ) == -1 ) {
+		warn( SHOW_ERRNO( "Failed to set TCP_NODELAY" ) );
+	}
+
 	return fd;
 }
 
-int socket_nbd_read_hello(int fd, off64_t * out_size)
+int nbd_check_hello( struct nbd_init_raw* init_raw, uint64_t* out_size )
 {
-	struct nbd_init init;
-	if ( 0 > readloop(fd, &init, sizeof(init)) ) {
-		warn( "Couldn't read init" );
+	if ( strncmp( init_raw->passwd, INIT_PASSWD, 8 ) != 0 ) {
+		warn( "wrong passwd" );
 		goto fail;
 	}
-	if (strncmp(init.passwd, INIT_PASSWD, 8) != 0) {
-		warn("wrong passwd");
-		goto fail;
-	}
-	if (be64toh(init.magic) != INIT_MAGIC) {
-		warn("wrong magic (%x)", be64toh(init.magic));
+	if ( be64toh( init_raw->magic ) != INIT_MAGIC ) {
+		warn( "wrong magic (%x)", be64toh( init_raw->magic ) );
 		goto fail;
 	}
+
 	if ( NULL != out_size ) {
-		*out_size = be64toh(init.size);
+		*out_size = be64toh( init_raw->size );
 	}
 
 	return 1;
 fail:
 	return 0;
+
 }
 
-void fill_request(struct nbd_request *request, int type, off64_t from, int len)
+int socket_nbd_read_hello( int fd, uint64_t* out_size )
+{
+	struct nbd_init_raw init_raw;
+
+
+	if ( 0 > readloop( fd, &init_raw, sizeof(init_raw) ) ) {
+		warn( "Couldn't read init" );
+		return 0;
+	}
+
+	return nbd_check_hello( &init_raw, out_size );
+}
+
+void nbd_hello_to_buf( struct nbd_init_raw *buf, off64_t out_size )
+{
+	struct nbd_init init;
+
+	memcpy( &init.passwd, INIT_PASSWD, 8 );
+	init.magic  = INIT_MAGIC;
+	init.size   = out_size;
+
+	memset( buf, 0, sizeof( struct nbd_init_raw ) ); // ensure reserved is 0s
+	nbd_h2r_init( &init, buf );
+
+	return;
+}
+
+int socket_nbd_write_hello(int fd, off64_t out_size)
+{
+	struct nbd_init_raw init_raw;
+	nbd_hello_to_buf( &init_raw, out_size );
+
+	if ( 0 > writeloop( fd, &init_raw, sizeof( init_raw ) ) ) {
+		warn( SHOW_ERRNO( "failed to write hello to socket" ) );
+		return 0;
+	}
+	return 1;
+}
+
+void fill_request(struct nbd_request *request, int type, uint64_t from, uint32_t len)
 {
 	request->magic  = htobe32(REQUEST_MAGIC);
 	request->type   = htobe32(type);
-	((int*) request->handle)[0] = rand();
-	((int*) request->handle)[1] = rand();
+	request->handle.w = (((uint64_t)rand()) << 32) | ((uint64_t)rand());
 	request->from   = htobe64(from);
 	request->len    = htobe32(len);
 }
@@ -69,7 +113,7 @@ void fill_request(struct nbd_request *request, int type, off64_t from, int len)
 void read_reply(int fd, struct nbd_request *request, struct nbd_reply *reply)
 {
 	struct nbd_reply_raw reply_raw;
-		
+
 	ERROR_IF_NEGATIVE(readloop(fd, &reply_raw, sizeof(struct nbd_reply_raw)),
 	  "Couldn't read reply");
 
@@ -81,7 +125,7 @@ void read_reply(int fd, struct nbd_request *request, struct nbd_reply *reply)
 	if (reply->error != 0) {
 		error("Server replied with error %d", reply->error);
 	}
-	if (strncmp(request->handle, reply->handle, 8) != 0) {
+	if (request->handle.w != reply->handle.w) {
 		error("Did not reply with correct handle");
 	}
 }
@@ -89,34 +133,35 @@ void read_reply(int fd, struct nbd_request *request, struct nbd_reply *reply)
 void wait_for_data( int fd, int timeout_secs )
 {
 	fd_set fds;
-	struct timeval tv = {timeout_secs, 0};
+	struct timeval tv = { timeout_secs, 0 };
 	int selected;
 
 	FD_ZERO( &fds );
 	FD_SET( fd, &fds );
-	selected = select( FD_SETSIZE, 
-			&fds, NULL, NULL, 
-			timeout_secs >=0 ? &tv : NULL );
+
+	selected = sock_try_select(
+		FD_SETSIZE, &fds, NULL, NULL, timeout_secs >=0 ? &tv : NULL
+	);
 
 	FATAL_IF( -1 == selected, "Select failed" );
 	ERROR_IF(  0 == selected, "Timed out waiting for reply" );
 }
 
 
-void socket_nbd_read(int fd, off64_t from, int len, int out_fd, void* out_buf, int timeout_secs)
+void socket_nbd_read(int fd, uint64_t from, uint32_t len, int out_fd, void* out_buf, int timeout_secs)
 {
 	struct nbd_request request;
 	struct nbd_reply   reply;
-	
+
 	fill_request(&request, REQUEST_READ, from, len);
 	FATAL_IF_NEGATIVE(writeloop(fd, &request, sizeof(request)),
 	  "Couldn't write request");
 
 	wait_for_data( fd, timeout_secs );
 	read_reply(fd, &request, &reply);
-	
+
 	if (out_buf) {
-		FATAL_IF_NEGATIVE(readloop(fd, out_buf, len), 
+		FATAL_IF_NEGATIVE(readloop(fd, out_buf, len),
 		  "Read failed");
 	}
 	else {
@@ -127,17 +172,17 @@ void socket_nbd_read(int fd, off64_t from, int len, int out_fd, void* out_buf, i
 	}
 }
 
-void socket_nbd_write(int fd, off64_t from, int len, int in_fd, void* in_buf, int timeout_secs)
+void socket_nbd_write(int fd, uint64_t from, uint32_t len, int in_fd, void* in_buf, int timeout_secs)
 {
 	struct nbd_request request;
 	struct nbd_reply   reply;
-	
+
 	fill_request(&request, REQUEST_WRITE, from, len);
 	ERROR_IF_NEGATIVE(writeloop(fd, &request, sizeof(request)),
 	  "Couldn't write request");
-	
+
 	if (in_buf) {
-		ERROR_IF_NEGATIVE(writeloop(fd, in_buf, len), 
+		ERROR_IF_NEGATIVE(writeloop(fd, in_buf, len),
 		  "Write failed");
 	}
 	else {
@@ -146,24 +191,12 @@ void socket_nbd_write(int fd, off64_t from, int len, int in_fd, void* in_buf, in
 			"Splice failed"
 		);
 	}
-	
+
 	wait_for_data( fd, timeout_secs );
 	read_reply(fd, &request, &reply);
 }
 
 
-void socket_nbd_entrust( int fd )
-{
-	struct nbd_request request;
-	struct nbd_reply   reply;
-
-	fill_request( &request, REQUEST_ENTRUST, 0, 0 );
-	FATAL_IF_NEGATIVE( writeloop( fd, &request, sizeof( request ) ),
-			"Couldn't write request");
-	read_reply( fd, &request, &reply );
-}
-
-
 int socket_nbd_disconnect( int fd )
 {
 	int success = 1;
@@ -179,10 +212,12 @@ int socket_nbd_disconnect( int fd )
 }
 
 #define CHECK_RANGE(error_type) { \
-	off64_t size;\
+	uint64_t size;\
 	int success = socket_nbd_read_hello(params->client, &size); \
 	if ( success ) {\
-		if (params->from < 0 || (params->from + params->len) > size) {\
+		uint64_t endpoint = params->from + params->len; \
+		if (endpoint > size || \
+				endpoint < params->from ) { /* this happens on overflow */ \
 			fatal(error_type \
 			  " request %d+%d is out of range given size %d", \
 			  params->from, params->len, size\
@@ -193,13 +228,13 @@ int socket_nbd_disconnect( int fd )
 		fatal( error_type " connection failed." );\
 	}\
 }
-  
+
 void do_read(struct mode_readwrite_params* params)
 {
 	params->client = socket_connect(&params->connect_to.generic, &params->connect_from.generic);
 	FATAL_IF_NEGATIVE( params->client, "Couldn't connect." );
 	CHECK_RANGE("read");
-	socket_nbd_read(params->client, params->from, params->len, 
+	socket_nbd_read(params->client, params->from, params->len,
 	  params->data_fd, NULL, 10);
 	close(params->client);
 }
@@ -209,7 +244,7 @@ void do_write(struct mode_readwrite_params* params)
 	params->client = socket_connect(&params->connect_to.generic, &params->connect_from.generic);
 	FATAL_IF_NEGATIVE( params->client, "Couldn't connect." );
 	CHECK_RANGE("write");
-	socket_nbd_write(params->client, params->from, params->len, 
+	socket_nbd_write(params->client, params->from, params->len,
 	  params->data_fd, NULL, 10);
 	close(params->client);
 }

src/common/readwrite.h

@@ -0,0 +1,23 @@
+#ifndef READWRITE_H
+
+#define READWRITE_H
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include "nbdtypes.h"
+
+int socket_connect(struct sockaddr* to, struct sockaddr* from);
+int socket_nbd_read_hello(int fd, uint64_t* size);
+int socket_nbd_write_hello(int fd, uint64_t size);
+void socket_nbd_read(int fd, uint64_t from, uint32_t len, int out_fd, void* out_buf, int timeout_secs);
+void socket_nbd_write(int fd, uint64_t from, uint32_t len, int out_fd, void* out_buf, int timeout_secs);
+int socket_nbd_disconnect( int fd );
+
+/* as you can see, we're slowly accumulating code that should really be in an
+ * NBD library */
+
+void nbd_hello_to_buf( struct nbd_init_raw* buf, uint64_t out_size );
+int nbd_check_hello( struct nbd_init_raw* init_raw, uint64_t* out_size );
+
+#endif
+

src/common/remote.c

@@ -15,12 +15,13 @@ void print_response( const char * response )
 	NULLCHECK( response );
 
 	exit_status = atoi(response);
-	response_text = strchr( response, ':' ) + 2;
+	response_text = strchr( response, ':' );
 
-	NULLCHECK( response_text );
+	FATAL_IF_NULL( response_text,
+			"Error parsing server response: '%s'", response );
 
 	out = exit_status > 0 ? stderr : stdout;
-	fprintf(out, "%s\n", response_text );
+	fprintf(out, "%s\n", response_text + 2);
 }
 
 void do_remote_command(char* command, char* socket_name, int argc, char** argv)
@@ -31,19 +32,19 @@ void do_remote_command(char* command, char* socket_name, int argc, char** argv)
 	int remote = socket(AF_UNIX, SOCK_STREAM, 0);
 	struct sockaddr_un address;
 	char response[max_response];
-	
+
 	memset(&address, 0, sizeof(address));
-	
+
 	FATAL_IF_NEGATIVE(remote, "Couldn't create client socket");
-	
+
 	address.sun_family = AF_UNIX;
 	strncpy(address.sun_path, socket_name, sizeof(address.sun_path));
-	
+
 	FATAL_IF_NEGATIVE(
 		connect(remote, (struct sockaddr*) &address, sizeof(address)),
 		"Couldn't connect to %s", socket_name
 	);
-	
+
 	write(remote, command, strlen(command));
 	write(remote, &newline, 1);
 	for (i=0; i<argc; i++) {
@@ -53,16 +54,14 @@ void do_remote_command(char* command, char* socket_name, int argc, char** argv)
 		write(remote, &newline, 1);
 	}
 	write(remote, &newline, 1);
-	
+
 	FATAL_IF_NEGATIVE(
 		read_until_newline(remote, response, max_response),
 		"Couldn't read response from %s", socket_name
 	);
-	
+
 	print_response( response );
 
 	exit(atoi(response));
-	
-	close(remote);
 }
 

src/common/self_pipe.c

@@ -51,7 +51,6 @@ struct self_pipe * self_pipe_create(void)
 {
 	struct self_pipe *sig = xmalloc( sizeof( struct self_pipe ) );
 	int fds[2];
-	int fcntl_err;
 	
 	if ( NULL == sig ) { return NULL; }
 
@@ -62,7 +61,7 @@ struct self_pipe * self_pipe_create(void)
 	}
 
 	if ( fcntl( fds[0], F_SETFL, O_NONBLOCK ) || fcntl( fds[1], F_SETFL, O_NONBLOCK ) ) {
-		fcntl_err = errno;
+		int fcntl_err = errno;
 		while( close( fds[0] ) == -1 && errno == EINTR );
 		while( close( fds[1] ) == -1 && errno == EINTR );
 		free( sig );

src/common/sockutil.c

@@ -0,0 +1,287 @@
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <netinet/tcp.h>
+#include <sys/un.h>
+
+#include "sockutil.h"
+#include "util.h"
+
+size_t sockaddr_size( const struct sockaddr* sa )
+{
+	struct sockaddr_un* un = (struct sockaddr_un*) sa;
+	size_t ret = 0;
+
+	switch( sa->sa_family ) {
+		case AF_INET:
+			ret = sizeof( struct sockaddr_in );
+			break;
+		case AF_INET6:
+			ret = sizeof( struct sockaddr_in6 );
+			break;
+		case AF_UNIX:
+			ret = sizeof( un->sun_family ) + SUN_LEN( un );
+			break;
+	}
+
+	return ret;
+}
+
+const char* sockaddr_address_string( const struct sockaddr* sa, char* dest, size_t len )
+{
+	NULLCHECK( sa );
+	NULLCHECK( dest );
+
+	struct sockaddr_in*  in  = ( struct sockaddr_in*  ) sa;
+	struct sockaddr_in6* in6 = ( struct sockaddr_in6* ) sa;
+	struct sockaddr_un*  un  = ( struct sockaddr_un*  ) sa;
+
+	unsigned short real_port = ntohs( in->sin_port ); // common to in and in6
+	const char* ret = NULL;
+
+	memset( dest, 0, len );
+
+	if ( sa->sa_family == AF_INET ) {
+		ret = inet_ntop( AF_INET, &in->sin_addr, dest, len );
+	} else if ( sa->sa_family == AF_INET6 ) {
+		ret = inet_ntop( AF_INET6, &in6->sin6_addr, dest, len );
+	} else if ( sa->sa_family == AF_UNIX ) {
+		ret = strncpy( dest, un->sun_path, SUN_LEN( un ) );
+	}
+
+	if ( ret == NULL ) {
+		strncpy( dest, "???", len );
+	}
+
+	if ( NULL != ret && real_port > 0 && sa->sa_family != AF_UNIX ) {
+		size_t size = strlen( dest );
+		snprintf( dest + size, len - size, " port %d", real_port );
+	}
+
+	return ret;
+}
+
+int sock_set_reuseaddr( int fd, int optval )
+{
+	return setsockopt( fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval) );
+}
+
+int sock_set_keepalive_params( int fd, int time, int intvl, int probes)
+{
+	if (sock_set_keepalive(fd, 1) ||
+		sock_set_tcp_keepidle(fd, time) ||
+		sock_set_tcp_keepintvl(fd, intvl) ||
+		sock_set_tcp_keepcnt(fd, probes)) {
+		return -1;
+	}
+	return 0;
+}
+
+int sock_set_keepalive( int fd, int optval )
+{
+	return setsockopt( fd, SOL_SOCKET, SO_KEEPALIVE, &optval, sizeof(optval) );
+}
+
+int sock_set_tcp_keepidle( int fd, int optval )
+{
+	return setsockopt( fd, IPPROTO_TCP, TCP_KEEPIDLE, &optval, sizeof(optval) );
+}
+
+int sock_set_tcp_keepintvl( int fd, int optval )
+{
+	return setsockopt( fd, IPPROTO_TCP, TCP_KEEPINTVL, &optval, sizeof(optval) );
+}
+
+int sock_set_tcp_keepcnt( int fd, int optval )
+{
+	return setsockopt( fd, IPPROTO_TCP, TCP_KEEPCNT, &optval, sizeof(optval) );
+}
+
+/* Set the tcp_nodelay option */
+int sock_set_tcp_nodelay( int fd, int optval )
+{
+	return setsockopt( fd, IPPROTO_TCP, TCP_NODELAY, &optval, sizeof(optval) );
+}
+
+int sock_set_tcp_cork( int fd, int optval )
+{
+	return setsockopt( fd, IPPROTO_TCP, TCP_CORK, &optval, sizeof(optval) );
+}
+
+int sock_set_nonblock( int fd, int optval )
+{
+	int flags = fcntl( fd, F_GETFL );
+
+	if ( flags == -1 ) {
+		return -1;
+	}
+
+	if ( optval ) {
+		flags = flags | O_NONBLOCK;
+	} else {
+		flags = flags & (~O_NONBLOCK);
+	}
+
+	return fcntl( fd, F_SETFL, flags );
+}
+
+int sock_try_bind( int fd, const struct sockaddr* sa )
+{
+	int bind_result;
+	char s_address[256];
+	int retry = 10;
+
+	sockaddr_address_string( sa, &s_address[0], 256 );
+
+	do {
+		bind_result = bind( fd, sa, sockaddr_size( sa ) );
+		if ( 0 == bind_result ) {
+			info( "Bound to %s", s_address );
+			break;
+		}
+		else {
+			warn( SHOW_ERRNO( "Couldn't bind to %s", s_address ) );
+
+			switch ( errno ) {
+				/* bind() can give us EACCES, EADDRINUSE, EADDRNOTAVAIL, EBADF,
+				 * EINVAL, ENOTSOCK, EFAULT, ELOOP, ENAMETOOLONG, ENOENT,
+				 * ENOMEM, ENOTDIR, EROFS
+				 *
+				 * Any of these other than  EADDRINUSE & EADDRNOTAVAIL signify
+				 * that there's a logic error somewhere.
+				 *
+				 * EADDRINUSE is fatal: if there's something already where we
+				 * want to be listening, we have no guarantees that any clients
+				 * will cope with it.
+				 */
+				case EADDRNOTAVAIL:
+					retry--;
+					if (retry) {
+						debug( "retrying" );
+						sleep( 1 );
+					}
+					continue;
+				case EADDRINUSE:
+					warn( "%s in use, giving up.", s_address );
+					retry = 0;
+					break;
+				default:
+					warn( "giving up" );
+					retry = 0;
+			}
+		}
+	} while ( retry );
+
+	return bind_result;
+}
+
+int sock_try_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
+{
+	int result;
+
+	do {
+		result = select(nfds, readfds, writefds, exceptfds, timeout);
+		if ( errno != EINTR ) {
+			break;
+		}
+
+	} while ( result == -1 );
+
+	return result;
+}
+
+int sock_try_connect( int fd, struct sockaddr* to, socklen_t addrlen, int wait )
+{
+	fd_set fds;
+	struct timeval tv = { wait, 0 };
+	int result = 0;
+
+	if ( sock_set_nonblock( fd, 1 ) == -1 ) {
+		warn( SHOW_ERRNO( "Failed to set socket non-blocking for connect()" ) );
+		return connect( fd, to, addrlen );
+	}
+
+	FD_ZERO( &fds );
+	FD_SET( fd, &fds );
+
+	do {
+		result = connect( fd, to, addrlen );
+
+		if ( result == -1 ) {
+			switch( errno ) {
+				case EINPROGRESS:
+					result = 0;
+					break; /* success */
+				case EAGAIN:
+				case EINTR:
+					/* Try connect() again. This only breaks out of the switch,
+					 * not the do...while loop. since result == -1, we go again.
+					 */
+					break;
+				default:
+					warn( SHOW_ERRNO( "Failed to connect()" ) );
+					goto out;
+			}
+		}
+	} while ( result == -1 );
+
+	if ( -1 == sock_try_select( FD_SETSIZE, NULL, &fds, NULL, &tv) ) {
+		warn( SHOW_ERRNO( "failed to select() on non-blocking connect" ) );
+		result = -1;
+		goto out;
+	}
+
+	if ( !FD_ISSET( fd, &fds ) ) {
+		result = -1;
+		errno = ETIMEDOUT;
+		goto out;
+	}
+
+	int scratch;
+	socklen_t s_size = sizeof( scratch );
+	if ( getsockopt( fd, SOL_SOCKET, SO_ERROR, &scratch, &s_size ) == -1 ) {
+		result = -1;
+		warn( SHOW_ERRNO( "getsockopt() failed" ) );
+		goto out;
+	}
+
+	if ( scratch == EINPROGRESS ) {
+		scratch = ETIMEDOUT;
+	}
+
+	result = scratch ? -1 : 0;
+	errno = scratch;
+
+out:
+	if ( sock_set_nonblock( fd, 0 ) == -1 ) {
+		warn( SHOW_ERRNO( "Failed to make socket blocking after connect()" ) );
+		return -1;
+	}
+
+	debug( "sock_try_connect: %i", result );
+	return result;
+}
+
+int sock_try_close( int fd )
+{
+	int result;
+
+	do {
+		result = close( fd );
+
+		if ( result == -1 ) {
+			if ( EINTR == errno ) {
+				continue; /* retry EINTR */
+			} else {
+				warn( SHOW_ERRNO( "Failed to close() fd %i", fd ) );
+				break; /* Other errors get reported */
+			}
+		}
+
+	} while( 0 );
+
+	return result;
+}
+

src/common/sockutil.h

@@ -0,0 +1,56 @@
+#ifndef SOCKUTIL_H
+
+#define SOCKUTIL_H
+
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <sys/select.h>
+
+/* Returns the size of the sockaddr, or 0 on error */
+size_t sockaddr_size(const struct sockaddr* sa);
+
+/* Convert a sockaddr into an address. Like inet_ntop, it returns dest if
+ * successful, NULL otherwise. In the latter case, dest will contain "???"
+ */
+const char* sockaddr_address_string(const struct sockaddr* sa, char* dest, size_t len);
+
+/* Configure TCP keepalive on a socket */
+int sock_set_keepalive_params( int fd, int time, int intvl, int probes);
+
+/* Set the SOL_KEEPALIVE otion */
+int sock_set_keepalive(int fd, int optval);
+
+/* Set the SOL_REUSEADDR otion */
+int sock_set_reuseaddr(int fd, int optval);
+
+/* Set the tcp_keepidle option */
+int sock_set_tcp_keepidle(int fd, int optval);
+
+/* Set the tcp_keepintvl option */
+int sock_set_tcp_keepintvl(int fd, int optval);
+
+/* Set the tcp_keepcnt option */
+int sock_set_tcp_keepcnt(int fd, int optval);
+
+/* Set the tcp_nodelay option */
+int sock_set_tcp_nodelay(int fd, int optval);
+
+/* Set the tcp_cork option */
+int sock_set_tcp_cork(int fd, int optval);
+
+int sock_set_nonblock(int fd, int optval);
+
+/* Attempt to bind the fd to the sockaddr, retrying common transient failures */
+int sock_try_bind(int fd, const struct sockaddr* sa);
+
+/* Try to call select(), retrying EINTR */
+int sock_try_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout);
+
+/* Try to call connect(), timing out after wait seconds */
+int sock_try_connect( int fd, struct sockaddr* to, socklen_t addrlen, int wait );
+
+/* Try to call close(), retrying EINTR */
+int sock_try_close( int fd );
+
+#endif
+

src/common/util.c

@@ -6,12 +6,14 @@
 #include <errno.h>
 #include <malloc.h>
 #include <unistd.h>
+#include <time.h>
 
 #include "util.h"
 
-pthread_key_t cleanup_handler_key; 
+pthread_key_t cleanup_handler_key;
 
 int log_level = 2;
+char *log_context = "";
 
 void error_init(void)
 {
@@ -21,10 +23,10 @@ void error_init(void)
 void error_handler(int fatal)
 {
 	DECLARE_ERROR_CONTEXT(context);
-	
+
 	if (context) {
 		longjmp(context->jmp, fatal ? 1 : 2 );
-	} 
+	}
 	else {
 		if ( fatal ) { abort(); }
 		else { pthread_exit((void*) 1); }
@@ -50,6 +52,25 @@ void mylog(int line_level, const char* format, ...)
 	va_end(argptr);
 }
 
+uint64_t monotonic_time_ms()
+{
+	struct timespec ts;
+	uint64_t seconds_ms, nanoseconds_ms;
+
+	FATAL_IF_NEGATIVE(
+		clock_gettime(CLOCK_MONOTONIC, &ts),
+		SHOW_ERRNO( "clock_gettime failed" )
+	);
+
+	seconds_ms = ts.tv_sec;
+	seconds_ms = seconds_ms * 1000;
+
+	nanoseconds_ms = ts.tv_nsec;
+	nanoseconds_ms = nanoseconds_ms / 1000000;
+
+	return seconds_ms + nanoseconds_ms;
+}
+
 
 void* xrealloc(void* ptr, size_t size)
 {

src/common/util.h

@@ -8,6 +8,7 @@
 #include <stdlib.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include <inttypes.h>
 
 void* xrealloc(void* ptr, size_t size);
 void* xmalloc(size_t size);
@@ -20,6 +21,9 @@ extern int log_level;
 /* set up the error globals */
 void error_init(void);
 
+/* some context for the overall process that appears on each log line */
+extern char *log_context;
+
 
 void exit_err( const char * );
 
@@ -85,9 +89,13 @@ void error_handler(int fatal);
 /* mylog a line at the given level (0 being most verbose) */
 void mylog(int line_level, const char* format, ...);
 
+/* Returns the current time, in milliseconds, from CLOCK_MONOTONIC */
+uint64_t monotonic_time_ms(void);
+
+
 #define levstr(i) (i==0?'D':(i==1?'I':(i==2?'W':(i==3?'E':'F'))))
 
-#define myloglev(level, msg, ...) mylog( level, "%c:%d %p %s:%d: "msg"\n", levstr(level), getpid(),pthread_self(), __FILE__, __LINE__, ##__VA_ARGS__ )
+#define myloglev(level, msg, ...) mylog( level, "%"PRIu64":%c:%d %p %s %s:%d: "msg"\n", monotonic_time_ms(), levstr(level), getpid(),pthread_self(), log_context, __FILE__, __LINE__, ##__VA_ARGS__ )
 
 #ifdef DEBUG
 #  define debug(msg, ...) myloglev(0, msg, ##__VA_ARGS__)
@@ -111,6 +119,7 @@ void mylog(int line_level, const char* format, ...);
 #define fatal(msg, ...) do { \
 	myloglev(4, msg, ##__VA_ARGS__); \
 	error_handler(1); \
+	exit(1); /* never-reached, this is to make static code analizer happy */ \
 } while(0)
 
 
@@ -148,6 +157,9 @@ void mylog(int line_level, const char* format, ...);
 
 #define NULLCHECK(value) FATAL_IF_NULL(value, "BUG: " #value " is null")
 
+#define SHOW_ERRNO( msg, ... ) msg ": %s (%i)", ##__VA_ARGS__, ( errno == 0 ? "EOF" : strerror(errno) ), errno
+
+#define WARN_IF_NEGATIVE( value, msg, ... ) if ( value < 0 ) { warn( msg, ##__VA_ARGS__ ); }
 
 #endif
 

src/ioutil.c

@@ -1,282 +0,0 @@
-#include <sys/mman.h>
-#include <sys/sendfile.h>
-#include <sys/ioctl.h>
-#include <sys/types.h>
-#include <linux/fs.h>
-#include <linux/fiemap.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <fcntl.h>
-
-#include "util.h"
-#include "bitset.h"
-
-struct bitset_mapping* build_allocation_map(int fd, uint64_t size, int resolution)
-{
-	unsigned int i;
-	struct bitset_mapping* allocation_map = bitset_alloc(size, resolution);
-	struct fiemap *fiemap_count = NULL, *fiemap = NULL;
-
-	fiemap_count = (struct fiemap*) xmalloc(sizeof(struct fiemap));
-
-	fiemap_count->fm_start = 0;
-	fiemap_count->fm_length = size;
-	fiemap_count->fm_flags = 0;
-	fiemap_count->fm_extent_count = 0;
-	fiemap_count->fm_mapped_extents = 0;
-
-	/* Find out how many extents there are */
-	if (ioctl(fd, FS_IOC_FIEMAP, fiemap_count) < 0) {
-		debug( "Couldn't get fiemap_count, returning no allocation_map" );
-		goto no_map;
-	}
-
-	/* Resize fiemap to allow us to read in the extents */
-	fiemap = (struct fiemap*)xmalloc(
-			sizeof(struct fiemap) + (
-				sizeof(struct fiemap_extent) * 
-				fiemap_count->fm_mapped_extents
-				)
-			); 
-
-	/* realloc makes valgrind complain a lot */
-	memcpy(fiemap, fiemap_count, sizeof(struct fiemap));
-	free( fiemap_count );
-
-	fiemap->fm_extent_count = fiemap->fm_mapped_extents;
-	fiemap->fm_mapped_extents = 0;
-
-	if (ioctl(fd, FS_IOC_FIEMAP, fiemap) < 0) { 
-		debug( "Couldn't get fiemap, returning no allocation_map" );
-		goto no_map;
-	}
-
-	for (i=0;i<fiemap->fm_mapped_extents;i++) {
-		bitset_set_range(
-			allocation_map, 
-			fiemap->fm_extents[i].fe_logical, 
-			fiemap->fm_extents[i].fe_length
-		);
-	}
-
-	/* This is pointlessly verbose for real discs, it's here as a
-	 * reference for pulling data out of the allocation map */
-	if ( 0 ) {
-		for (i=0; i<(size/resolution); i++) {
-			debug("map[%d] = %d%d%d%d%d%d%d%d",
-					i,
-					(allocation_map->bits[i] & 1) == 1,
-					(allocation_map->bits[i] & 2) == 2,
-					(allocation_map->bits[i] & 4) == 4,
-					(allocation_map->bits[i] & 8) == 8,
-					(allocation_map->bits[i] & 16) == 16,
-					(allocation_map->bits[i] & 32) == 32,
-					(allocation_map->bits[i] & 64) == 64,
-					(allocation_map->bits[i] & 128) == 128
-			     );
-		}
-	}
-
-
-	free(fiemap);
-
-	debug("Successfully built allocation map");
-	return allocation_map;
-
-no_map:
-	free( allocation_map );
-	if ( NULL != fiemap ) { free( fiemap ); }
-	if ( NULL != fiemap_count ) { free( fiemap_count ); }
-	return NULL;
-}
-
-
-int open_and_mmap(const char* filename, int* out_fd, off64_t *out_size, void **out_map)
-{
-	off64_t size;
-	
-	/* O_DIRECT seems to be intermittently supported.  Leaving it as
-	 * a compile-time option for now. */
-#ifdef DIRECT_IO
-	*out_fd = open(filename, O_RDWR | O_DIRECT | O_SYNC );
-#else
-	*out_fd = open(filename, O_RDWR | O_SYNC );
-#endif
-
-	if (*out_fd < 1) {
-		warn("open(%s) failed: does it exist?", filename);
-		return *out_fd;
-	}
-	
-	size = lseek64(*out_fd, 0, SEEK_END);
-	if (size < 0) {
-		warn("lseek64() failed");
-		return size;
-	}
-	if (out_size) {
-		*out_size = size;
-	}
-	
-	if (out_map) {
-		*out_map = mmap64(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, 
-		  *out_fd, 0);
-		if (((long) *out_map) == -1) {
-			warn("mmap64() failed");
-			return -1;
-		}
-	}
-	debug("opened %s size %ld on fd %d @ %p", filename, size, *out_fd, *out_map);
-	
-	return 0;
-}
-
-
-int writeloop(int filedes, const void *buffer, size_t size)
-{
-	size_t written=0;
-	while (written < size) {
-		ssize_t result = write(filedes, buffer+written, size-written);
-		if (result == -1) { return -1; }
-		written += result;
-	}
-	return 0;
-}
-
-int readloop(int filedes, void *buffer, size_t size)
-{
-	size_t readden=0;
-	while (readden < size) {
-		ssize_t result = read(filedes, buffer+readden, size-readden);
-		if (result == 0 /* EOF */ || result == -1 /* error */) {
-			return -1;
-		}
-		readden += result;
-	}
-	return 0;
-}
-
-int sendfileloop(int out_fd, int in_fd, off64_t *offset, size_t count)
-{
-	size_t sent=0;
-	while (sent < count) {
-		ssize_t result = sendfile64(out_fd, in_fd, offset, count-sent);
-		debug("sendfile64(out_fd=%d, in_fd=%d, offset=%p, count-sent=%ld) = %ld", out_fd, in_fd, offset, count-sent, result);
-
-		if (result == -1) { return -1; }
-		sent += result;
-		debug("sent=%ld, count=%ld", sent, count);
-	}
-	debug("exiting sendfileloop");
-	return 0;
-}
-
-#include <errno.h>
-ssize_t spliceloop(int fd_in, loff_t *off_in, int fd_out, loff_t *off_out, size_t len, unsigned int flags2)
-{
-	const unsigned int flags = SPLICE_F_MORE|SPLICE_F_MOVE|flags2;
-	size_t spliced=0;
-	
-	//debug("spliceloop(%d, %ld, %d, %ld, %ld)", fd_in, off_in ? *off_in : 0, fd_out, off_out ? *off_out : 0, len);
-	
-	while (spliced < len) {
-		ssize_t result = splice(fd_in, off_in, fd_out, off_out, len, flags);
-		if (result < 0) {
-			//debug("result=%ld (%s), spliced=%ld, len=%ld", result, strerror(errno), spliced, len);
-			if (errno == EAGAIN && (flags & SPLICE_F_NONBLOCK) ) {
-				return spliced;
-			} 
-			else {
-				return -1;
-			}
-		} else {
-			spliced += result;
-			//debug("result=%ld (%s), spliced=%ld, len=%ld", result, strerror(errno), spliced, len);
-		}
-	}
-	
-	return spliced;
-}
-
-int splice_via_pipe_loop(int fd_in, int fd_out, size_t len)
-{
-
-	int pipefd[2]; /* read end, write end */
-	size_t spliced=0;
-	
-	if (pipe(pipefd) == -1) {
-		return -1;
-	}
-	
-	while (spliced < len) {
-		ssize_t run = len-spliced;
-		ssize_t s2, s1 = spliceloop(fd_in, NULL, pipefd[1], NULL, run, SPLICE_F_NONBLOCK);
-		/*if (run > 65535)
-			run = 65535;*/
-		if (s1 < 0) { break; }
-		
-		s2 = spliceloop(pipefd[0], NULL, fd_out, NULL, s1, 0);
-		if (s2 < 0) { break; }
-		spliced += s2;
-	}
-	close(pipefd[0]);
-	close(pipefd[1]);
-	
-	return spliced < len ? -1 : 0;
-}
-
-/* Reads single bytes from fd until either an EOF or a newline appears.
- * If an EOF occurs before a newline, returns -1.  The line is lost.
- * Inserts the read bytes (without the newline) into buf, followed by a
- * trailing NULL.
- * Returns the number of read bytes: the length of the line without the
- * newline, plus the trailing null.
- */
-int read_until_newline(int fd, char* buf, int bufsize)
-{
-	int cur;
-	
-	for (cur=0; cur < bufsize; cur++) {
-		int result = read(fd, buf+cur, 1);
-		if (result <= 0) { return -1; }
-		if (buf[cur] == 10) { 
-			buf[cur] = '\0';
-			break; 
-		}
-	}
-	
-	return cur+1;
-}
-
-int read_lines_until_blankline(int fd, int max_line_length, char ***lines)
-{
-	int lines_count = 0;
-	char line[max_line_length+1];
-	*lines = NULL;
-	
-	memset(line, 0, max_line_length+1);
-	
-	while (1) {
-		int readden = read_until_newline(fd, line, max_line_length);
-		/* readden will be:
-		 * 1 for an empty line
-		 * -1 for an eof
-		 * -1 for a read error
-		 */
-		if (readden <= 1) { return lines_count; }
-		*lines = xrealloc(*lines, (lines_count+1) * sizeof(char*));
-		(*lines)[lines_count] = strdup(line);
-		if ((*lines)[lines_count][0] == 0) {
-			return lines_count;
-		}
-		lines_count++;
-	}
-}
-
-
-int fd_is_closed( int fd_in )
-{
-	int errno_old = errno;
-	int result = fcntl( fd_in, F_GETFL ) < 0;
-	errno = errno_old;
-	return result;
-}

src/listen.c

@@ -1,120 +0,0 @@
-#include "listen.h"
-#include "serve.h"
-#include "util.h"
-#include "flexnbd.h"
-
-#include <stdlib.h>
-
-struct listen * listen_create( 
-		struct flexnbd * flexnbd,
-		char* s_ip_address, 
-		char* s_rebind_ip_address, 
-		char* s_port, 
-		char* s_rebind_port, 
-		char* s_file,
-		int default_deny,
-		int acl_entries, 
-		char** s_acl_entries,
-		int max_nbd_clients )
-{
-	NULLCHECK( flexnbd );
-	struct listen * listen;
-
-	listen = (struct listen *)xmalloc( sizeof( struct listen ) );
-	listen->flexnbd = flexnbd;
-	listen->init_serve = server_create( 
-			flexnbd,
-			s_ip_address, 
-			s_port, 
-			s_file,
-			default_deny, 
-			acl_entries, 
-			s_acl_entries, 
-			1, 0);
-	listen->main_serve = server_create( 
-			flexnbd,
-			s_rebind_ip_address ? s_rebind_ip_address : s_ip_address, 
-			s_rebind_port ? s_rebind_port : s_port,
-			s_file,
-			default_deny, 
-			acl_entries, 
-			s_acl_entries, 
-			max_nbd_clients, 1);
-	return listen;
-}
-
-
-void listen_destroy( struct listen * listen )
-{
-	NULLCHECK( listen );
-	free( listen );
-}
-
-
-struct server *listen_switch( struct listen * listen )
-{
-	NULLCHECK( listen );
-
-	/* TODO: Copy acl from init_serve to main_serve */
-	/* TODO: rename underlying file from foo.INCOMPLETE to foo */
-	
-	server_destroy( listen->init_serve );
-	listen->init_serve = NULL;
-	info( "Switched to the main server, serving." );
-	return listen->main_serve;
-}
-
-
-void listen_cleanup( struct listen * listen )
-{
-	NULLCHECK( listen );
-
-	if ( flexnbd_switch_locked( listen->flexnbd ) ) { 
-		flexnbd_unlock_switch( listen->flexnbd ); 
-	}
-}
-
-int do_listen( struct listen * listen )
-{
-	NULLCHECK( listen );
-
-	int have_control = 0;
-
-	flexnbd_lock_switch( listen->flexnbd );
-	{
-		flexnbd_set_server( listen->flexnbd, listen->init_serve );
-	}
-	flexnbd_unlock_switch( listen->flexnbd );
-
-	/* WATCH FOR RACES HERE: flexnbd->serve is set, but the server
-	 * isn't running yet and the switch lock is released.
-	 */
-	have_control = do_serve( listen->init_serve );
-
-
-	if( have_control ) {
-		info( "Taking control.");
-		flexnbd_switch( listen->flexnbd, listen_switch );
-		/* WATCH FOR RACES HERE: the server hasn't been
-		 * restarted before we release the flexnbd switch lock.
-		 * do_serve doesn't return, so there's not a lot of
-		 * choice about that.
-		 */
-		do_serve( listen->main_serve );
-	}
-	else {
-		warn("Failed to take control, giving up.");
-		server_destroy( listen->init_serve );
-		listen->init_serve = NULL;
-	}
-	/* TODO: here we must signal the control thread to stop before
-	 * it tries to  */
-	server_destroy( listen->main_serve );
-	listen->main_serve = NULL;
-
-	debug("Listen done, cleaning up");
-	listen_cleanup( listen );
-
-	return have_control;
-}
-

src/listen.h

@@ -1,28 +0,0 @@
-#ifndef LISTEN_H
-#define LISTEN_H
-
-#include "flexnbd.h"
-#include "serve.h"
-
-struct listen {
-	struct flexnbd * flexnbd;
-	struct server * init_serve;
-	struct server * main_serve;
-};
-
-struct listen * listen_create( 
-		struct flexnbd * flexnbd,
-		char* s_ip_address, 
-		char* s_rebind_ip_address, 
-		char* s_port, 
-		char* s_rebind_port, 
-		char* s_file,
-		int default_deny,
-		int acl_entries, 
-		char** s_acl_entries,
-		int max_nbd_clients );
-void listen_destroy( struct listen* );
-
-int do_listen( struct listen * );
-
-#endif

src/main.c

@@ -2,13 +2,16 @@
 #include "mode.h"
 
 #include <signal.h>
-
+#include <stdlib.h>
+#include <time.h>
 
 int main(int argc, char** argv)
 {
 	signal(SIGPIPE, SIG_IGN); /* calls to splice() unhelpfully throw this */
 	error_init();
 
+	srand(time(NULL));
+
 	if (argc < 2) {
 		exit_err( help_help_text );
 	}

src/mirror.c

@@ -1,614 +0,0 @@
-/*  FlexNBD server (C) Bytemark Hosting 2012
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-
-#include "mirror.h"
-#include "serve.h"
-#include "util.h"
-#include "ioutil.h"
-#include "parse.h"
-#include "readwrite.h"
-#include "bitset.h"
-#include "self_pipe.h"
-#include "status.h"
-
-
-#include <stdlib.h>
-#include <string.h>
-#include <sys/un.h>
-#include <unistd.h>
-
-struct mirror * mirror_alloc(
-		union mysockaddr * connect_to,
-		union mysockaddr * connect_from,
-		int max_Bps,
-		int action_at_finish,
-		struct mbox * commit_signal)
-{
-	struct mirror * mirror;
-
-	mirror = xmalloc(sizeof(struct mirror));
-	mirror->connect_to = connect_to;
-	mirror->connect_from = connect_from;
-	mirror->max_bytes_per_second = max_Bps;
-	mirror->action_at_finish = action_at_finish;
-	mirror->commit_signal = commit_signal;
-	mirror->commit_state = MS_UNKNOWN;
-
-	return mirror;
-}
-
-void mirror_set_state_f( struct mirror * mirror, enum mirror_state state )
-{
-	NULLCHECK( mirror );
-	mirror->commit_state = state;
-}
-
-#define mirror_set_state( mirror, state ) do{\
-	debug( "Mirror state => " #state );\
-	mirror_set_state_f( mirror, state );\
-} while(0)
-
-enum mirror_state mirror_get_state( struct mirror * mirror )
-{
-	NULLCHECK( mirror );
-	return mirror->commit_state;
-}
-
-
-void mirror_init( struct mirror * mirror, const char * filename )
-{
-	int map_fd;
-	off64_t size;
-
-	NULLCHECK( mirror );
-	NULLCHECK( filename );
-
-	FATAL_IF_NEGATIVE(
-		open_and_mmap(
-			filename, 
-			&map_fd,
-			&size, 
-			(void**) &mirror->mapped
-		),
-		"Failed to open and mmap %s",
-		filename
-	);
-	
-	mirror->dirty_map = bitset_alloc(size, 4096);
-
-}
-
-
-/* Call this before a mirror attempt. */
-void mirror_reset( struct mirror * mirror )
-{
-	NULLCHECK( mirror );
-	NULLCHECK( mirror->dirty_map );
-	mirror_set_state( mirror, MS_INIT );
-	bitset_set(mirror->dirty_map);
-}
-
-
-struct mirror * mirror_create(
-		const char * filename,
-		union mysockaddr * connect_to,
-		union mysockaddr * connect_from,
-		int max_Bps,
-		int action_at_finish,
-		struct mbox * commit_signal)
-{
-	/* FIXME: shouldn't map_fd get closed? */
-	struct mirror * mirror;
-
-	mirror = mirror_alloc( connect_to,
-			connect_from,
-			max_Bps,
-			action_at_finish,
-			commit_signal);
-	
-	mirror_init( mirror, filename );
-	mirror_reset( mirror );
-
-
-	return mirror;
-}
-
-
-void mirror_destroy( struct mirror *mirror )
-{
-	NULLCHECK( mirror );
-	free(mirror->connect_to);
-	free(mirror->connect_from);
-	free(mirror->dirty_map);
-	free(mirror);
-}
-
-
-/** The mirror code will split NBD writes, making them this long as a maximum */
-static const int mirror_longest_write = 8<<20;
-
-/** If, during a mirror pass, we have sent this number of bytes or fewer, we
- *  go to freeze the I/O and finish it off.  This is just a guess.
- */
-static const unsigned int mirror_last_pass_after_bytes_written = 100<<20;
-
-/** The largest number of full passes we'll do - the last one will always 
- *  cause the I/O to freeze, however many bytes are left to copy.
- */
-static const int mirror_maximum_passes = 7;
-
-/* A single mirror pass over the disc, optionally locking IO around the
- * transfer.
- */
-int mirror_pass(struct server * serve, int should_lock, uint64_t *written)
-{
-	uint64_t current = 0;
-	int success = 1;
-	struct bitset_mapping *map = serve->mirror->dirty_map;
-	*written = 0;
-
-	while (current < serve->size) {
-		int run = bitset_run_count(map, current, mirror_longest_write);
-
-		debug("mirror current=%ld, run=%d", current, run);
-
-		/* FIXME: we could avoid sending sparse areas of the 
-		 * disc here, and probably save a lot of bandwidth and
-		 * time (if we know the destination starts off zeroed).
-		 */ 
-		if (bitset_is_set_at(map, current)) {
-			/* We've found a dirty area, send it */
-			debug("^^^ writing");
-
-			/* We need to stop the main thread from working 
-			 * because it might corrupt the dirty map.  This
-			 * is likely to slow things down but will be
-			 * safe.
-			 */
-			if (should_lock) { server_lock_io( serve ); }
-			{
-				debug("in lock block");
-				/** FIXME: do something useful with bytes/second */
-
-				/** FIXME: error handling code here won't unlock */
-				socket_nbd_write( serve->mirror->client, 
-						current,
-						run,
-						0,
-						serve->mirror->mapped + current,
-						MS_REQUEST_LIMIT_SECS);
-
-				/* now mark it clean */
-				bitset_clear_range(map, current, run);
-				debug("leaving lock block");
-			}
-			if (should_lock) { server_unlock_io( serve ); }
-
-			*written += run;
-		}
-		current += run;
-
-		if (serve->mirror->signal_abandon) {
-			debug("Abandon message received" );
-			success = 0;
-			break;
-		}
-	}
-
-	return success;
-}
-
-
-void mirror_give_control( struct mirror * mirror )
-{
-	debug( "mirror: entrusting and disconnecting" );
-	/* TODO: set up an error handler to clean up properly on ERROR.
-	 */
-
-	/* A transfer of control is expressed as a 3-way handshake.
-	 * First, We send a REQUEST_ENTRUST. If this fails to be
-	 * received, this thread will simply block until the server is
-	 * restarted. If the remote end doesn't understand it, it'll
-	 * disconnect us, and an ERROR *should* bomb this thread.
-	 * FIXME: make the ERROR work.
-	 * If we get an explicit error back from the remote end, then
-	 * again, this thread will bomb out.
-	 * On receiving a valid response, we send a REQUEST_DISCONNECT,
-	 * and we quit without checking for a response.  This is the
-	 * remote server's signal to assume control of the file.  The
-	 * reason we don't check for a response is the state we end up
-	 * in if the final message goes astray: if we lose the
-	 * REQUEST_DISCONNECT, the sender has quit and the receiver
-	 * hasn't had a signal to take over yet, so the data is safe.
-	 * If we were to wait for a response to the REQUEST_DISCONNECT,
-	 * the sender and receiver would *both* be servicing write
-	 * requests while the response was in flight, and if the
-	 * response went astray we'd have two servers claiming
-	 * responsibility for the same data.
-	 *
-	 * The meaning of these is as follows:
-	 * The entrust signifies that all the data has been sent, and
-	 * the client is currently paused but not disconnected.
-	 * The disconnect signifies that the client has been
-	 * safely prevented from making any more writes.
-	 *
-	 * Since we lock io and close the server it in mirror_on_exit before
-	 * releasing, we don't actually need to take any action between the
-	 * two here.
-	 */
-	socket_nbd_entrust( mirror->client );
-	socket_nbd_disconnect( mirror->client );
-}
-
-
-/* THIS FUNCTION MUST ONLY BE CALLED WITH THE SERVER'S IO LOCKED. */
-void mirror_on_exit( struct server * serve )
-{
-	/* Send an explicit entrust and disconnect. After this
-	 * point we cannot allow any reads or writes to the local file.
-	 * We do this *before* trying to shut down the server so that if
-	 * the transfer of control fails, we haven't stopped the server
-	 * and already-connected clients don't get needlessly
-	 * disconnected.
-	 */
-	debug( "mirror_give_control");
-	mirror_give_control( serve->mirror );
-
-	/* If we're still here, the transfer of control went ok, and the
-	 * remote is listening (or will be shortly).  We can shut the
-	 * server down.
-	 *
-	 * It doesn't matter if we get new client connections before
-	 * now, the IO lock will stop them from doing anything.
-	 */
-	debug("serve_signal_close");
-	serve_signal_close( serve );
-
-	/* We have to wait until the server is closed before unlocking
-	 * IO.  This is because the client threads check to see if the
-	 * server is still open before reading or writing inside their
-	 * own locks. If we don't wait for the close, there's no way to
-	 * guarantee the server thread will win the race and we risk the
-	 * clients seeing a "successful" write to a dead disc image.
-	 */
-	debug("serve_wait_for_close");
-	serve_wait_for_close( serve );
-	info("Mirror sent.");
-}
-
-
-void mirror_cleanup( struct server * serve,
-		int fatal __attribute__((unused)))
-{
-	NULLCHECK( serve );
-	struct mirror * mirror = serve->mirror;
-	NULLCHECK( mirror );
-	info( "Cleaning up mirror thread");
-
-	if( mirror->client && mirror->client > 0 ){
-		close( mirror->client );
-	}
-	mirror->client = -1;
-
-	if( server_io_locked( serve ) ){ server_unlock_io( serve ); }
-}
-
-
-
-int mirror_connect( struct mirror * mirror, off64_t local_size )
-{
-	struct sockaddr * connect_from = NULL;
-	int connected =  0;
-
-	if ( mirror->connect_from ) {
-		connect_from = &mirror->connect_from->generic;
-	}
-
-	NULLCHECK( mirror->connect_to );
-
-	mirror->client = socket_connect(&mirror->connect_to->generic, connect_from);
-	if ( 0 < mirror->client ) {
-		fd_set fds;
-		struct timeval tv = { MS_HELLO_TIME_SECS, 0};
-		FD_ZERO( &fds );
-		FD_SET( mirror->client, &fds );
-
-		FATAL_UNLESS( 0 <= select( FD_SETSIZE, &fds, NULL, NULL, &tv ),
-				"Select failed." );
-
-		if( FD_ISSET( mirror->client, &fds ) ){
-			off64_t remote_size;
-			if ( socket_nbd_read_hello( mirror->client, &remote_size ) ) {
-				if( remote_size == local_size ){
-					connected = 1;
-					mirror_set_state( mirror, MS_GO );
-				}
-				else {
-					warn("Remote size (%d) doesn't match local (%d)", 
-							remote_size, local_size );
-					mirror_set_state( mirror, MS_FAIL_SIZE_MISMATCH );
-				}
-			}
-			else {
-				warn( "Mirror attempt rejected." );
-				mirror_set_state( mirror, MS_FAIL_REJECTED );
-			}
-		}
-		else {
-			warn( "No NBD Hello received." );
-			mirror_set_state( mirror, MS_FAIL_NO_HELLO );
-		}
-
-		if ( !connected ) { close( mirror->client ); }
-	}
-	else {
-		warn( "Mirror failed to connect.");
-		mirror_set_state( mirror, MS_FAIL_CONNECT );
-	}
-
-	return connected;
-}
-
-
-
-void mirror_run( struct server *serve )
-{
-	NULLCHECK( serve );
-	NULLCHECK( serve->mirror );
-
-	int pass;
-	uint64_t written;
-
-	info("Starting mirror" );
-	for (pass=0; pass < mirror_maximum_passes-1; pass++) {
-
-		debug("mirror start pass=%d", pass);
-		if ( !mirror_pass( serve, 1, &written ) ){ 
-			debug("Failed mirror pass state is %d", mirror_get_state( serve->mirror ) );
-			debug("pass failed, giving up");
-			return; }
-		
-		/* if we've not written anything */
-		if (written < mirror_last_pass_after_bytes_written) { break; }
-	}
-
-	server_lock_io( serve );
-	{
-		if ( mirror_pass( serve, 0, &written ) &&
-				ACTION_EXIT == serve->mirror->action_at_finish) {
-			debug("exit!");
-			mirror_on_exit( serve );
-			info("Server closed, quitting "
-					"after successful migration");
-		} 
-	}
-	server_unlock_io( serve );
-}
-
-
-void mbox_post_mirror_state( struct mbox * mbox, enum mirror_state st )
-{
-	NULLCHECK( mbox );
-	enum mirror_state * contents = xmalloc( sizeof( enum mirror_state ) );
-
-	*contents = st;
-
-	mbox_post( mbox, contents );
-}
-
-
-void mirror_signal_commit( struct mirror * mirror )
-{
-	NULLCHECK( mirror );
-
-	mbox_post_mirror_state( mirror->commit_signal, 
-			mirror_get_state( mirror ) );
-}
-
-/** Thread launched to drive mirror process 
- * This is needed for two reasons: firstly, it decouples the mirroring
- * from the control thread (although that's less valid with mboxes
- * passing state back and forth) and to provide an error context so that
- * retries can be cleanly handled without a bespoke error handling
- * mechanism.
- * */
-void* mirror_runner(void* serve_params_uncast)
-{
-	/* The supervisor thread relies on there not being any ERROR
-	 * calls until after the mirror_signal_commit() call in this
-	 * function.
-	 * However, *after* that, we should call ERROR_* instead of
-	 * FATAL_* wherever possible.
-	 */
-	struct server *serve = (struct server*) serve_params_uncast;
-
-	NULLCHECK( serve );
-	NULLCHECK( serve->mirror );
-	struct mirror * mirror = serve->mirror;
-	NULLCHECK( mirror->dirty_map );
-
-	error_set_handler( (cleanup_handler *) mirror_cleanup, serve );
-
-	info( "Connecting to mirror" );
-	
-	time_t start_time = time(NULL);
-	int connected = mirror_connect( mirror, serve->size );
-	mirror_signal_commit( mirror );
-	if ( !connected ) { goto abandon_mirror; }
-
-	/* After this point, if we see a failure we need to disconnect
-	 * and retry everything from mirror_set_state(_, MS_INIT), but
-	 * *without* signaling the commit or abandoning the mirror.
-	 * */
-	
-	if ( (time(NULL) - start_time) > MS_CONNECT_TIME_SECS ){ 
-		/* If we get here, then we managed to connect but the
-		 * control thread feeding status back to the user will
-		 * have gone away, leaving the user without meaningful
-		 * feedback. In this instance, they have to assume a
-		 * failure, so we can't afford to let the mirror happen.
-		 * We have to set the state to avoid a race.
-		 */
-		mirror_set_state( mirror, MS_FAIL_CONNECT );
-		warn( "Mirror connected, but too slowly" );
-		goto abandon_mirror;
-	}
-
-	mirror_run( serve );
-
-	mirror_set_state( mirror, MS_DONE );
-abandon_mirror:
-	return NULL;
-}
-
-
-struct mirror_super * mirror_super_create(
-		const char * filename,
-		union mysockaddr * connect_to,
-		union mysockaddr * connect_from,
-		int max_Bps,
-		int action_at_finish,
-		struct mbox * state_mbox)
-{
-	struct mirror_super * super = xmalloc( sizeof( struct mirror_super) );
-	super->mirror = mirror_create( 
-			filename, 
-			connect_to, 
-			connect_from, 
-			max_Bps, 
-			action_at_finish,
-			mbox_create() ) ;
-	super->state_mbox = state_mbox;
-	return super;
-}
-
-
-/* Post the current state of the mirror into super->state_mbox.*/
-void mirror_super_signal_committed( 
-		struct mirror_super * super ,
-		enum mirror_state commit_state )
-{
-	NULLCHECK( super );
-	NULLCHECK( super->state_mbox );
-
-	mbox_post_mirror_state( 
-			super->state_mbox, 
-			commit_state );
-}
-
-
-void mirror_super_destroy( struct mirror_super * super )
-{
-	NULLCHECK( super );
-
-	mbox_destroy( super->mirror->commit_signal );
-	mirror_destroy( super->mirror );
-	free( super );
-}
-
-
-/* The mirror supervisor thread.  Responsible for kicking off retries if
- * the mirror thread fails.
- * The mirror and mirror_super objects are never freed, and the
- * mirror_super_runner thread is never joined.
- */
-void * mirror_super_runner( void * serve_uncast )
-{
-	struct server * serve = (struct server *) serve_uncast;
-	NULLCHECK( serve );
-	NULLCHECK( serve->mirror );
-	NULLCHECK( serve->mirror_super );
-
-	int first_pass = 1;
-	int should_retry = 0;
-	int success = 0;
-
-	struct mirror * mirror = serve->mirror;
-	struct mirror_super *  super  = serve->mirror_super;
-
-	do {
-		FATAL_IF( 0 != pthread_create(
-					&mirror->thread, 
-					NULL, 
-					mirror_runner, 
-					serve),
-				"Failed to create mirror thread");
-
-		debug("Supervisor waiting for commit signal");
-		enum mirror_state * commit_state = 
-			mbox_receive( mirror->commit_signal );
-
-		debug( "Supervisor got commit signal" );
-		if ( first_pass ) {
-			/* Only retry if the connection attempt was
-			 * successful.  Otherwise the user will see an
-			 * error reported while we're still trying to
-			 * retry behind the scenes.
-			 */
-			should_retry = *commit_state == MS_GO;
-			/* Only send this signal the first time */
-			mirror_super_signal_committed(
-					super, 
-					*commit_state);
-			debug("Mirror supervisor committed");
-		}
-		/* We only care about the value of the commit signal on
-		 * the first pass, so this is ok
-		 */
-		free( commit_state );
-
-		debug("Supervisor waiting for mirror thread" );
-		pthread_join( mirror->thread, NULL );
-
-		success = MS_DONE == mirror_get_state( mirror );
-
-		if( success ){ 
-			info( "Mirror supervisor success, exiting" ); }
-		else if ( mirror->signal_abandon ) {
-			info( "Mirror abandoned" );
-			should_retry = 0;
-		}
-		else if (should_retry){
-			info( "Mirror failed, retrying" );
-		}
-		else { info( "Mirror failed before commit, giving up" ); }
-
-		first_pass = 0;
-
-		if ( should_retry ) { 
-			/* We don't want to hammer the destination too
-			 * hard, so if this is a retry, insert a delay. */
-			sleep( MS_RETRY_DELAY_SECS );
-
-			/* We also have to reset the bitmap to be sure
-			 * we transfer everything */
-			mirror_reset( mirror );
-		}
-
-	} 
-	while ( should_retry && !success );
-
-	serve->mirror = NULL;
-	serve->mirror_super = NULL;
-
-	mirror_super_destroy( super );
-	debug( "Mirror supervisor done." );
-
-	return NULL;
-}
-
-

src/proxy-main.c

@@ -0,0 +1,171 @@
+#include <signal.h>
+#include <stdlib.h>
+#include <time.h>
+
+#include "mode.h"
+#include "util.h"
+#include "proxy.h"
+
+
+static struct option proxy_options[] = {
+	GETOPT_HELP,
+	GETOPT_ADDR,
+	GETOPT_PORT,
+	GETOPT_CONNECT_ADDR,
+	GETOPT_CONNECT_PORT,
+	GETOPT_BIND,
+	GETOPT_CACHE,
+	GETOPT_QUIET,
+	GETOPT_VERBOSE,
+	{0}
+};
+static char proxy_short_options[] = "hl:p:C:P:b:" SOPT_QUIET SOPT_VERBOSE;
+static char proxy_help_text[] =
+	"Usage: flexnbd-proxy <options>\n\n"
+	"Resiliently proxy an NBD connection between client and server\n"
+	"We can listen on TCP or UNIX socket, but only connect to TCP servers.\n\n"
+	HELP_LINE
+	"\t--" OPT_ADDR ",-l <ADDR>\tThe address we will bind to as a proxy.\n"
+	"\t--" OPT_PORT ",-p <PORT>\tThe port we will bind to as a proxy, if required.\n"
+	"\t--" OPT_CONNECT_ADDR ",-C <ADDR>\tAddress of the proxied server.\n"
+	"\t--" OPT_CONNECT_PORT ",-P <PORT>\tPort of the proxied server.\n"
+	"\t--" OPT_BIND ",-b <ADDR>\tThe address we connect from, as a proxy.\n"
+	"\t--" OPT_CACHE ",-c[=<CACHE-BYTES>]\tUse a RAM read cache of the given size.\n"
+	QUIET_LINE
+	VERBOSE_LINE;
+
+static char proxy_default_cache_size[] = "4096";
+
+void read_proxy_param(
+			int c,
+			char **downstream_addr,
+			char **downstream_port,
+			char **upstream_addr,
+			char **upstream_port,
+			char **bind_addr,
+			char **cache_bytes)
+{
+	switch( c ) {
+		case 'h' :
+			fprintf( stdout, "%s\n", proxy_help_text );
+			exit( 0 );
+		case 'l':
+			*downstream_addr = optarg;
+			break;
+		case 'p':
+			*downstream_port = optarg;
+			break;
+		case 'C':
+			*upstream_addr = optarg;
+			break;
+		case 'P':
+			*upstream_port = optarg;
+			break;
+		case 'b':
+			*bind_addr = optarg;
+			break;
+		case 'c':
+			*cache_bytes = optarg ? optarg : proxy_default_cache_size;
+			break;
+		case 'q':
+			log_level = QUIET_LOG_LEVEL;
+			break;
+		case 'v':
+			log_level = VERBOSE_LOG_LEVEL;
+			break;
+		default:
+			exit_err( proxy_help_text );
+			break;
+	}
+}
+
+struct proxier * proxy = NULL;
+
+void my_exit(int signum)
+{
+	info( "Exit signalled (%i)", signum );
+	if ( NULL != proxy ) {
+		proxy_cleanup( proxy );
+	};
+	exit( 0 );
+}
+
+int main( int argc, char *argv[] )
+{
+	int c;
+	char *downstream_addr = NULL;
+	char *downstream_port = NULL;
+	char *upstream_addr   = NULL;
+	char *upstream_port   = NULL;
+	char *bind_addr       = NULL;
+	char *cache_bytes     = NULL;
+	int success;
+
+	sigset_t mask;
+	struct sigaction exit_action;
+
+	sigemptyset( &mask );
+	sigaddset( &mask, SIGTERM );
+	sigaddset( &mask, SIGQUIT );
+	sigaddset( &mask, SIGINT );
+
+	exit_action.sa_handler = my_exit;
+	exit_action.sa_mask = mask;
+	exit_action.sa_flags = 0;
+
+	srand(time(NULL));
+
+	while (1) {
+		c = getopt_long( argc, argv, proxy_short_options, proxy_options, NULL );
+		if ( -1 == c ) { break; }
+		read_proxy_param( c,
+				&downstream_addr,
+				&downstream_port,
+				&upstream_addr,
+				&upstream_port,
+				&bind_addr,
+				&cache_bytes
+		);
+	}
+
+	if ( NULL == downstream_addr  ){
+		fprintf( stderr, "--addr is required.\n" );
+		exit_err( proxy_help_text );
+	} else if ( NULL == upstream_addr || NULL == upstream_port ){
+		fprintf( stderr, "both --conn-addr and --conn-port are required.\n" );
+		exit_err( proxy_help_text );
+	}
+
+	proxy = proxy_create(
+		downstream_addr,
+		downstream_port,
+		upstream_addr,
+		upstream_port,
+		bind_addr,
+		cache_bytes
+	);
+
+	/* Set these *after* proxy has been assigned to */
+	sigaction(SIGTERM, &exit_action, NULL);
+	sigaction(SIGQUIT, &exit_action, NULL);
+	sigaction(SIGINT,  &exit_action, NULL);
+	signal(SIGPIPE, SIG_IGN); /* calls to splice() unhelpfully throw this */
+
+	if ( NULL != downstream_port ) {
+		info(
+			"Proxying between %s %s (downstream) and %s %s (upstream)",
+			downstream_addr, downstream_port, upstream_addr, upstream_port
+		);
+	} else {
+		info(
+			"Proxying between %s (downstream) and %s %s (upstream)",
+			downstream_addr, upstream_addr, upstream_port
+		);
+	}
+
+	success = do_proxy( proxy );
+	proxy_destroy( proxy );
+
+	return success ? 0 : 1;
+}
+

src/proxy/prefetch.c

@@ -0,0 +1,68 @@
+#include "prefetch.h"
+#include "util.h"
+
+
+struct prefetch* prefetch_create( size_t size_bytes ){
+
+	struct prefetch* out = xmalloc( sizeof( struct prefetch ) );
+	NULLCHECK( out );
+	
+	out->buffer = xmalloc( size_bytes );
+	NULLCHECK( out->buffer );
+
+	out->size = size_bytes;
+	out->is_full = 0;
+	out->from = 0;
+	out->len = 0;
+
+	return out;
+
+}
+
+void prefetch_destroy( struct prefetch *prefetch ) {
+	if( prefetch ) {
+		free( prefetch->buffer );
+		free( prefetch );
+	}
+}
+
+size_t prefetch_size( struct prefetch *prefetch){
+	if ( prefetch ) {
+		return prefetch->size;
+	} else {
+		return 0;
+	}
+}
+
+void prefetch_set_is_empty( struct prefetch *prefetch ){
+	prefetch_set_full( prefetch, 0 );
+}
+
+void prefetch_set_is_full( struct prefetch *prefetch ){
+	prefetch_set_full( prefetch, 1 );
+}
+
+void prefetch_set_full( struct prefetch *prefetch, int val ){
+	if( prefetch ) {
+		prefetch->is_full = val;
+	}
+}
+
+int prefetch_is_full( struct prefetch *prefetch ){
+	if( prefetch ) {
+		return prefetch->is_full;
+	} else {
+		return 0;
+	}
+}
+
+int prefetch_contains( struct prefetch *prefetch, uint64_t from, uint32_t len ){
+	NULLCHECK( prefetch );
+	return from >= prefetch->from &&
+		from + len <= prefetch->from + prefetch->len;
+}
+
+char *prefetch_offset( struct prefetch *prefetch, uint64_t from ){
+	NULLCHECK( prefetch );
+	return prefetch->buffer + (from - prefetch->from);
+}

src/proxy/prefetch.h

@@ -0,0 +1,33 @@
+#ifndef PREFETCH_H
+#define PREFETCH_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+#define PREFETCH_BUFSIZE 4096
+
+struct prefetch {
+	/* True if there is data in the buffer. */
+        int is_full;
+	/* The start point of the current content of buffer */
+        uint64_t from;
+	/* The length of the current content of buffer */
+        uint32_t len;
+
+	/* The total size of the buffer, in bytes. */
+	size_t size;
+
+        char *buffer;
+};
+
+struct prefetch* prefetch_create( size_t size_bytes );
+void prefetch_destroy( struct prefetch *prefetch );
+size_t prefetch_size( struct prefetch *);
+void prefetch_set_is_empty( struct prefetch *prefetch );
+void prefetch_set_is_full( struct prefetch *prefetch );
+void prefetch_set_full( struct prefetch *prefetch, int val );
+int prefetch_is_full( struct prefetch *prefetch );
+int prefetch_contains( struct prefetch *prefetch, uint64_t from, uint32_t len );
+char *prefetch_offset( struct prefetch *prefetch, uint64_t from );
+
+#endif

src/proxy/proxy.c

@@ -0,0 +1,978 @@
+#include "proxy.h"
+#include "readwrite.h"
+
+#include "prefetch.h"
+
+
+#include "ioutil.h"
+#include "sockutil.h"
+#include "util.h"
+
+#include <errno.h>
+
+#include <sys/socket.h>
+#include <netinet/tcp.h>
+
+struct proxier* proxy_create(
+	char* s_downstream_address,
+	char* s_downstream_port,
+	char* s_upstream_address,
+	char* s_upstream_port,
+	char* s_upstream_bind,
+	char* s_cache_bytes )
+{
+	struct proxier* out;
+	out = xmalloc( sizeof( struct proxier ) );
+
+	FATAL_IF_NULL(s_downstream_address, "Listen address not specified");
+	NULLCHECK( s_downstream_address );
+
+	FATAL_UNLESS(
+		parse_to_sockaddr( &out->listen_on.generic, s_downstream_address ),
+		"Couldn't parse downstream address %s"
+	);
+
+	if ( out->listen_on.family != AF_UNIX ) {
+		FATAL_IF_NULL( s_downstream_port, "Downstream port not specified" );
+		NULLCHECK( s_downstream_port );
+		parse_port( s_downstream_port, &out->listen_on.v4 );
+	}
+
+	FATAL_IF_NULL(s_upstream_address, "Upstream address not specified");
+	NULLCHECK( s_upstream_address );
+
+	FATAL_UNLESS(
+		parse_ip_to_sockaddr( &out->connect_to.generic, s_upstream_address ),
+		"Couldn't parse upstream address '%s'",
+		s_upstream_address
+	);
+
+	FATAL_IF_NULL( s_upstream_port, "Upstream port not specified" );
+	NULLCHECK( s_upstream_port );
+	parse_port( s_upstream_port, &out->connect_to.v4 );
+
+	if ( s_upstream_bind ) {
+		FATAL_IF_ZERO(
+			parse_ip_to_sockaddr( &out->connect_from.generic, s_upstream_bind ),
+			"Couldn't parse bind address '%s'",
+			s_upstream_bind
+		);
+		out->bind = 1;
+	}
+
+	out->listen_fd = -1;
+	out->downstream_fd = -1;
+	out->upstream_fd = -1;
+
+	out->prefetch = NULL;
+	if ( s_cache_bytes ){
+		int cache_bytes = atoi( s_cache_bytes );
+		/* leaving this off or setting a cache size of zero or
+		 * less results in no cache.
+		 */
+		if ( cache_bytes >= 0 ) {
+			out->prefetch = prefetch_create( cache_bytes );
+		}
+	}
+
+	out->init.buf = xmalloc( sizeof( struct nbd_init_raw ) );
+	out->req.buf  = xmalloc( NBD_MAX_SIZE );
+	out->rsp.buf  = xmalloc( NBD_MAX_SIZE );
+
+	log_context = xmalloc( strlen(s_upstream_address) + strlen(s_upstream_port) + 2 );
+	sprintf(log_context, "%s:%s", s_upstream_address, s_upstream_port);
+
+	return out;
+}
+
+int proxy_prefetches( struct proxier* proxy ) {
+	NULLCHECK( proxy );
+	return proxy->prefetch != NULL;
+}
+
+int proxy_prefetch_bufsize( struct proxier* proxy ){
+	NULLCHECK( proxy );
+	return prefetch_size( proxy->prefetch );
+}
+
+void proxy_destroy( struct proxier* proxy )
+{
+	free( proxy->init.buf );
+	free( proxy->req.buf );
+	free( proxy->rsp.buf );
+	prefetch_destroy( proxy->prefetch );
+
+	free( proxy );
+}
+
+/* Shared between our two different connect_to_upstream paths */
+void proxy_finish_connect_to_upstream( struct proxier *proxy, uint64_t size );
+
+/* Try to establish a connection to our upstream server. Return 1 on success,
+ * 0 on failure. this is a blocking call that returns a non-blocking socket.
+ */
+int proxy_connect_to_upstream( struct proxier* proxy )
+{
+	struct sockaddr* connect_from = NULL;
+	if ( proxy->bind ) {
+		connect_from = &proxy->connect_from.generic;
+	}
+
+	int fd = socket_connect( &proxy->connect_to.generic, connect_from );
+	uint64_t size = 0;
+
+	if ( -1 == fd ) {
+		return 0;
+	}
+
+	if( !socket_nbd_read_hello( fd, &size ) ) {
+		WARN_IF_NEGATIVE(
+			sock_try_close( fd ),
+			"Couldn't close() after failed read of NBD hello on fd %i", fd
+		);
+		return 0;
+	}
+
+	proxy->upstream_fd = fd;
+	sock_set_nonblock( fd, 1 );
+	proxy_finish_connect_to_upstream( proxy, size );
+
+	return 1;
+}
+
+/* First half of non-blocking connection to upstream. Gets as far as calling
+ * connect() on a non-blocking socket.
+ */
+void proxy_start_connect_to_upstream( struct proxier* proxy )
+{
+	int fd, result;
+	struct sockaddr* from = NULL;
+	struct sockaddr* to = &proxy->connect_to.generic;
+
+	if ( proxy->bind ) {
+		from = &proxy->connect_from.generic;
+	}
+
+	fd = socket( to->sa_family , SOCK_STREAM, 0 );
+
+	if( fd < 0 ) {
+		warn( SHOW_ERRNO( "Couldn't create socket to reconnect to upstream" ) );
+		return;
+	}
+
+	info( "Beginning non-blocking connection to upstream on fd %i", fd );
+
+	if ( NULL != from ) {
+		if ( 0 > bind( fd, from, sockaddr_size( from ) ) ) {
+			warn( SHOW_ERRNO( "bind() to source address failed" ) );
+		}
+	}
+
+	result = sock_set_nonblock( fd, 1 );
+	if ( result == -1 ) {
+		warn( SHOW_ERRNO( "Failed to set upstream fd %i non-blocking", fd ) );
+		goto error;
+	}
+
+	result = connect( fd, to, sockaddr_size( to ) );
+	if ( result == -1 && errno != EINPROGRESS ) {
+		warn( SHOW_ERRNO( "Failed to start connect()ing to upstream!" ) );
+		goto error;
+	}
+
+	proxy->upstream_fd = fd;
+	return;
+
+error:
+	if ( sock_try_close( fd ) == -1 ) {
+		/* Non-fatal leak, although still nasty */
+		warn( SHOW_ERRNO( "Failed to close fd for upstream %i", fd ) );
+	}
+	return;
+}
+
+void proxy_finish_connect_to_upstream( struct proxier *proxy, uint64_t size ) {
+
+	if ( proxy->upstream_size == 0 ) {
+		info( "Size of upstream image is %"PRIu64" bytes", size );
+	} else if ( proxy->upstream_size != size ) {
+		warn(
+			"Size changed from %"PRIu64" to %"PRIu64" bytes",
+			proxy->upstream_size, size
+		);
+	}
+
+	proxy->upstream_size = size;
+
+	if ( AF_UNIX != proxy->connect_to.family ) {
+		if ( sock_set_tcp_nodelay( proxy->upstream_fd, 1 ) == -1 ) {
+			warn( SHOW_ERRNO( "Failed to set TCP_NODELAY" ) );
+		}
+	}
+
+	info( "Connected to upstream on fd %i", proxy->upstream_fd );
+
+	return;
+}
+
+void proxy_disconnect_from_upstream( struct proxier* proxy )
+{
+	if ( -1 != proxy->upstream_fd ) {
+		info("Closing upstream connection on fd %i", proxy->upstream_fd );
+
+		/* TODO: An NBD disconnect would be pleasant here */
+		WARN_IF_NEGATIVE(
+			sock_try_close( proxy->upstream_fd ),
+			"Failed to close() fd %i when disconnecting from upstream",
+			proxy->upstream_fd
+		);
+		proxy->upstream_fd = -1;
+	}
+}
+
+
+/** Prepares a listening socket for the NBD server, binding etc. */
+void proxy_open_listen_socket(struct proxier* params)
+{
+	NULLCHECK( params );
+
+	params->listen_fd = socket(params->listen_on.family, SOCK_STREAM, 0);
+	FATAL_IF_NEGATIVE(
+		params->listen_fd, SHOW_ERRNO( "Couldn't create listen socket" )
+	);
+
+	/* Allow us to restart quickly */
+	FATAL_IF_NEGATIVE(
+		sock_set_reuseaddr(params->listen_fd, 1),
+		SHOW_ERRNO( "Couldn't set SO_REUSEADDR" )
+	);
+
+	if( AF_UNIX != params->listen_on.family ) {
+		FATAL_IF_NEGATIVE(
+			sock_set_tcp_nodelay(params->listen_fd, 1),
+			SHOW_ERRNO( "Couldn't set TCP_NODELAY" )
+		);
+	}
+
+	FATAL_UNLESS_ZERO(
+		sock_try_bind( params->listen_fd, &params->listen_on.generic ),
+		SHOW_ERRNO( "Failed to bind to listening socket" )
+	);
+
+	/* We're only serving one client at a time, hence backlog of 1 */
+	FATAL_IF_NEGATIVE(
+		listen(params->listen_fd, 1),
+		SHOW_ERRNO( "Failed to listen on listening socket" )
+	);
+
+	info( "Now listening for incoming connections" );
+
+	return;
+}
+
+typedef enum {
+	EXIT,
+	WRITE_TO_DOWNSTREAM,
+	READ_FROM_DOWNSTREAM,
+	CONNECT_TO_UPSTREAM,
+	READ_INIT_FROM_UPSTREAM,
+	WRITE_TO_UPSTREAM,
+	READ_FROM_UPSTREAM
+} proxy_session_states;
+
+static char* proxy_session_state_names[] = {
+  "EXIT",
+  "WRITE_TO_DOWNSTREAM",
+  "READ_FROM_DOWNSTREAM",
+  "CONNECT_TO_UPSTREAM",
+  "READ_INIT_FROM_UPSTREAM",
+  "WRITE_TO_UPSTREAM",
+  "READ_FROM_UPSTREAM"
+};
+
+static inline int proxy_state_upstream( int state )
+{
+	return state == CONNECT_TO_UPSTREAM || state == READ_INIT_FROM_UPSTREAM ||
+	       state == WRITE_TO_UPSTREAM   || state == READ_FROM_UPSTREAM;
+}
+
+int proxy_prefetch_for_request( struct proxier* proxy, int state )
+{
+	NULLCHECK( proxy );
+	struct nbd_request* req = &proxy->req_hdr;
+	struct nbd_reply* rsp = &proxy->rsp_hdr;
+
+	struct nbd_request_raw* req_raw = (struct nbd_request_raw*) proxy->req.buf;
+	struct nbd_reply_raw *rsp_raw = (struct nbd_reply_raw*) proxy->rsp.buf;
+
+	int is_read = ( req->type & REQUEST_MASK ) == REQUEST_READ;
+
+	if ( is_read ) {
+		/* See if we can respond with what's in our prefetch
+		 * cache */
+		if ( prefetch_is_full( proxy->prefetch ) &&
+			prefetch_contains( proxy->prefetch, req->from, req->len ) ) {
+			/* HUZZAH!  A match! */
+			debug( "Prefetch hit!" );
+
+			/* First build a reply header */
+			rsp->magic = REPLY_MAGIC;
+			rsp->error = 0;
+			memcpy( &rsp->handle, &req->handle, 8 );
+
+			/* now copy it into the response */
+			nbd_h2r_reply( rsp, rsp_raw );
+
+			/* and the data */
+			memcpy(
+				proxy->rsp.buf + NBD_REPLY_SIZE,
+				prefetch_offset( proxy->prefetch, req->from ),
+				req->len
+			);
+
+			proxy->rsp.size = NBD_REPLY_SIZE + req->len;
+			proxy->rsp.needle = 0;
+
+			/* return early, our work here is done */
+			return WRITE_TO_DOWNSTREAM;
+		}
+	}
+	else {
+		/* Safety catch.  If we're sending a write request, we
+		 * blow away the cache.  This is very pessimistic, but
+		 * it's simpler (and therefore safer) than working out
+		 * whether we can keep it or not.
+		 */
+		debug( "Blowing away prefetch cache on type %d request.", req->type );
+		prefetch_set_is_empty( proxy->prefetch );
+	}
+
+	debug( "Prefetch cache MISS!");
+
+	uint64_t prefetch_start = req->from;
+	/* We prefetch what we expect to be the next request. */
+	uint64_t prefetch_end = req->from + ( req->len * 2 );
+
+	/* We only want to consider prefetching if we know we're not
+	 * getting too much data back, if it's a read request, and if
+	 * the prefetch won't try to read past the end of the file.
+	 */
+	int prefetching = 
+		req->len <= prefetch_size( proxy->prefetch ) && 
+		is_read &&
+		prefetch_start < prefetch_end && 
+		prefetch_end <= proxy->upstream_size; 
+
+	/* We pull the request out of the proxy struct, rewrite the
+	 * request size, and write it back.
+	 */
+	if ( prefetching ) {
+		proxy->is_prefetch_req = 1;
+		proxy->prefetch_req_orig_len = req->len;
+
+		req->len *= 2;
+
+		debug( "Prefetching additional %"PRIu32" bytes", 
+				req->len - proxy->prefetch_req_orig_len );
+		nbd_h2r_request( req, req_raw );
+	}
+
+	return state;
+}
+
+int proxy_prefetch_for_reply( struct proxier* proxy, int state )
+{
+	size_t prefetched_bytes;
+
+	if ( !proxy->is_prefetch_req ) {
+		return state;
+	}
+
+	prefetched_bytes = proxy->req_hdr.len - proxy->prefetch_req_orig_len;
+
+	debug( "Prefetched additional %d bytes", prefetched_bytes );
+	memcpy(
+		proxy->prefetch->buffer,
+		proxy->rsp.buf + proxy->prefetch_req_orig_len + NBD_REPLY_SIZE,
+		prefetched_bytes
+	);
+
+	proxy->prefetch->from = proxy->req_hdr.from + proxy->prefetch_req_orig_len;
+	proxy->prefetch->len = prefetched_bytes;
+
+	/* We've finished with proxy->req by now, so don't need to alter it to make
+	 * it look like the request was before prefetch */
+
+	/* Truncate the bytes we'll write downstream */
+	proxy->req_hdr.len = proxy->prefetch_req_orig_len;
+	proxy->rsp.size -= prefetched_bytes;
+
+	/* And we need to reset these */
+	prefetch_set_is_full( proxy->prefetch );
+	proxy->is_prefetch_req = 0;
+
+	return state;
+}
+
+
+
+int proxy_read_from_downstream( struct proxier *proxy, int state )
+{
+	ssize_t count;
+
+	struct nbd_request_raw* request_raw = (struct nbd_request_raw*) proxy->req.buf;
+	struct nbd_request*     request = &(proxy->req_hdr);
+
+//	assert( state == READ_FROM_DOWNSTREAM );
+
+	count = iobuf_read( proxy->downstream_fd, &proxy->req, NBD_REQUEST_SIZE );
+
+	if ( count == -1 ) {
+		warn( SHOW_ERRNO( "Couldn't read request from downstream" ) );
+		return EXIT;
+	}
+
+	if ( proxy->req.needle == NBD_REQUEST_SIZE ) {
+		nbd_r2h_request( request_raw, request );
+
+		if ( ( request->type & REQUEST_MASK ) == REQUEST_DISCONNECT ) {
+			info( "Received disconnect request from client" );
+			return EXIT;
+		}
+
+		/* Simple validations */
+		if ( ( request->type & REQUEST_MASK ) == REQUEST_READ ) {
+			if (request->len > ( NBD_MAX_SIZE - NBD_REPLY_SIZE ) ) {
+				warn( "NBD read request size %"PRIu32" too large", request->len );
+				return EXIT;
+			}
+		}
+		if ( (request->type & REQUEST_MASK ) == REQUEST_WRITE ) {
+			if (request->len > ( NBD_MAX_SIZE - NBD_REQUEST_SIZE ) ) {
+				warn( "NBD write request size %"PRIu32" too large", request->len );
+				return EXIT;
+			}
+
+			proxy->req.size += request->len;
+		}
+	}
+
+	if ( proxy->req.needle == proxy->req.size ) {
+		debug(
+			"Received NBD request from downstream. type=%"PRIu32" from=%"PRIu64" len=%"PRIu32,
+			request->type, request->from, request->len
+		);
+
+		/* Finished reading, so advance state. Leave size untouched so the next
+		 * state knows how many bytes to write */
+		proxy->req.needle = 0;
+		return WRITE_TO_UPSTREAM;
+	}
+
+	return state;
+}
+
+int proxy_continue_connecting_to_upstream( struct proxier* proxy, int state )
+{
+	int error, result;
+	socklen_t len = sizeof( error );
+
+//	assert( state == CONNECT_TO_UPSTREAM );
+
+	result = getsockopt(
+		proxy->upstream_fd, SOL_SOCKET, SO_ERROR,  &error, &len
+	);
+
+	if ( result == -1 ) {
+		warn( SHOW_ERRNO( "Failed to tell if connected to upstream" ) );
+		return state;
+	}
+
+	if ( error != 0 ) {
+		errno = error;
+		warn( SHOW_ERRNO( "Failed to connect to upstream" ) );
+		return state;
+	}
+
+	/* Data may have changed while we were disconnected */
+	prefetch_set_is_empty( proxy->prefetch );
+
+	info( "Connected to upstream on fd %i", proxy->upstream_fd );
+	return READ_INIT_FROM_UPSTREAM;
+}
+
+int proxy_read_init_from_upstream( struct proxier* proxy, int state )
+{
+	ssize_t count;
+
+//	assert( state == READ_INIT_FROM_UPSTREAM );
+
+	count = iobuf_read( proxy->upstream_fd, &proxy->init, sizeof( struct nbd_init_raw ) );
+
+	if ( count == -1 ) {
+		warn( SHOW_ERRNO( "Failed to read init from upstream" ) );
+		goto disconnect;
+	}
+
+	if ( proxy->init.needle == proxy->init.size ) {
+		uint64_t upstream_size;
+		if ( !nbd_check_hello( (struct nbd_init_raw*) proxy->init.buf, &upstream_size ) ) {
+			warn( "Upstream sent invalid init" );
+			goto disconnect;
+		}
+
+		/* Currently, we only get disconnected from upstream (so needing to come
+		 * here) when we have an outstanding request. If that becomes false,
+		 * we'll need to choose the right state to return to here */
+		proxy->init.needle = 0;
+		return WRITE_TO_UPSTREAM;
+	}
+
+	return state;
+
+disconnect:
+	proxy->init.needle = 0;
+	proxy->init.size = 0;
+	return CONNECT_TO_UPSTREAM;
+}
+
+int proxy_write_to_upstream( struct proxier* proxy, int state )
+{
+	ssize_t count;
+
+//	assert( state == WRITE_TO_UPSTREAM );
+
+	/* FIXME: We may set cork=1 multiple times as a result of this idiom.
+	 * Not a serious problem, but we could do better
+	 */
+	if ( proxy->req.needle == 0 && AF_UNIX != proxy->connect_to.family ) {
+		if ( sock_set_tcp_cork( proxy->upstream_fd, 1 ) == -1 ) {
+			warn( SHOW_ERRNO( "Failed to set TCP_CORK" ) );
+		}
+	}
+
+	count = iobuf_write( proxy->upstream_fd, &proxy->req );
+
+	if ( count == -1 ) {
+		warn( SHOW_ERRNO( "Failed to send request to upstream" ) );
+		proxy->req.needle = 0;
+		// We're throwing the socket away so no need to uncork
+		return CONNECT_TO_UPSTREAM;
+	}
+
+	if ( proxy->req.needle == proxy->req.size ) {
+		/* Request sent. Advance to reading the response from upstream. We might
+		 * still need req.size if reading the reply fails - we disconnect
+		 * and resend the reply in that case - so keep it around for now. */
+		proxy->req.needle = 0;
+
+		if ( AF_UNIX != proxy->connect_to.family ) {
+			if ( sock_set_tcp_cork( proxy->upstream_fd, 0 ) == -1 ) {
+				warn( SHOW_ERRNO( "Failed to unset TCP_CORK" ) );
+				// TODO: should we return to CONNECT_TO_UPSTREAM in this instance?
+			}
+		}
+
+		return READ_FROM_UPSTREAM;
+	}
+
+	return state;
+}
+
+int proxy_read_from_upstream( struct proxier* proxy, int state )
+{
+	ssize_t count;
+
+	struct nbd_reply*     reply     = &(proxy->rsp_hdr);
+	struct nbd_reply_raw* reply_raw = (struct nbd_reply_raw*) proxy->rsp.buf;
+
+	/* We can't assume the NBD_REPLY_SIZE + req->len is what we'll get back */
+	count = iobuf_read( proxy->upstream_fd, &proxy->rsp, NBD_REPLY_SIZE );
+
+	if ( count == -1 ) {
+		warn( SHOW_ERRNO( "Failed to get reply from upstream" ) );
+		goto disconnect;
+	}
+
+	if ( proxy->rsp.needle == NBD_REPLY_SIZE ) {
+		nbd_r2h_reply( reply_raw, reply );
+
+		if ( reply->magic != REPLY_MAGIC ) {
+			warn( "Reply magic is incorrect" );
+			goto disconnect;
+		}
+
+		if ( reply->error != 0 ) {
+			warn( "NBD error returned from upstream: %"PRIu32, reply->error );
+			goto disconnect;
+		}
+
+		if ( ( proxy->req_hdr.type & REQUEST_MASK ) == REQUEST_READ ) {
+			/* Get the read reply data too. */
+			proxy->rsp.size += proxy->req_hdr.len;
+		}
+	}
+
+	if ( proxy->rsp.size == proxy->rsp.needle ) {
+		debug( "NBD reply received from upstream." );
+		proxy->rsp.needle = 0;
+		return WRITE_TO_DOWNSTREAM;
+	}
+
+	return state;
+
+disconnect:
+	proxy->rsp.needle = 0;
+	proxy->rsp.size = 0;
+	return CONNECT_TO_UPSTREAM;
+}
+
+
+int proxy_write_to_downstream( struct proxier* proxy, int state )
+{
+	ssize_t count;
+
+//	assert( state == WRITE_TO_DOWNSTREAM );
+
+	if ( !proxy->hello_sent ) {
+		info( "Writing init to downstream" );
+	}
+
+	count = iobuf_write( proxy->downstream_fd, &proxy->rsp );
+
+	if ( count == -1 ) {
+		warn( SHOW_ERRNO( "Failed to write to downstream" ) );
+		return EXIT;
+	}
+
+	if ( proxy->rsp.needle == proxy->rsp.size ) {
+		if ( !proxy->hello_sent ) {
+			info( "Hello message sent to client" );
+			proxy->hello_sent = 1;
+		} else {
+			debug( "Reply sent" );
+			proxy->req_count++;
+		}
+
+		/* We're done with the request & response buffers now */
+		proxy->req.size = 0;
+		proxy->req.needle = 0;
+		proxy->rsp.size = 0;
+		proxy->rsp.needle = 0;
+		return READ_FROM_DOWNSTREAM;
+	}
+
+	return state;
+}
+
+/* Non-blocking proxy session. Simple(ish) state machine. We read from d/s until
+ * we have a full request, then try to write that request u/s. If writing fails,
+ * we reconnect to upstream and retry. Once we've successfully written, we
+ * attempt to read the reply. If that fails or times out (we give it 30 seconds)
+ * then we disconnect from u/s and go back to trying to reconnect and resend.
+ *
+ * This is the second-simplest NBD proxy I can think of. The first version was
+ * non-blocking I/O, but it was getting impossible to manage exceptional stuff
+ */
+void proxy_session( struct proxier* proxy )
+{
+	uint64_t state_started = monotonic_time_ms();
+	int old_state = EXIT;
+	int state;
+	int connect_to_upstream_cooldown = 0;
+
+
+	/* First action: Write hello to downstream */
+	nbd_hello_to_buf( (struct nbd_init_raw *) proxy->rsp.buf, proxy->upstream_size );
+	proxy->rsp.size = sizeof( struct nbd_init_raw );
+	proxy->rsp.needle = 0;
+	state = WRITE_TO_DOWNSTREAM;
+
+
+	info( "Beginning proxy session on fd %i", proxy->downstream_fd );
+
+	while( state != EXIT ) {
+
+		struct timeval select_timeout = {
+			.tv_sec = 0,
+			.tv_usec = 0
+		};
+
+		struct timeval *select_timeout_ptr = NULL;
+
+		int result; /* used by select() */
+
+		fd_set rfds;
+		fd_set wfds;
+
+		FD_ZERO( &rfds );
+		FD_ZERO( &wfds );
+
+		if ( state != old_state ) {
+			state_started = monotonic_time_ms();
+
+			debug(
+				"State transition from %s to %s",
+				proxy_session_state_names[old_state],
+				proxy_session_state_names[state]
+			);
+		} else {
+			debug( "Proxy is in state %s", proxy_session_state_names[state], state );
+		}
+
+		old_state = state;
+
+		switch( state ) {
+			case READ_FROM_DOWNSTREAM:
+				FD_SET( proxy->downstream_fd, &rfds );
+				break;
+			case WRITE_TO_DOWNSTREAM:
+				FD_SET( proxy->downstream_fd, &wfds );
+				break;
+			case WRITE_TO_UPSTREAM:
+				select_timeout.tv_sec = 15;
+				FD_SET(proxy->upstream_fd, &wfds );
+				break;
+			case CONNECT_TO_UPSTREAM:
+				/* upstream_fd is now -1 */
+				proxy_disconnect_from_upstream( proxy );
+
+				if ( connect_to_upstream_cooldown ) {
+					connect_to_upstream_cooldown = 0;
+					select_timeout.tv_sec = 3;
+				} else {
+					proxy_start_connect_to_upstream( proxy );
+
+					if ( proxy->upstream_fd == -1 ) {
+						warn( SHOW_ERRNO( "Error acquiring socket to upstream" ) );
+						continue;
+					}
+					FD_SET( proxy->upstream_fd, &wfds );
+					select_timeout.tv_sec = 15;
+				}
+				break;
+			case READ_INIT_FROM_UPSTREAM:
+			case READ_FROM_UPSTREAM:
+				select_timeout.tv_sec = 15;
+				FD_SET( proxy->upstream_fd, &rfds );
+				break;
+		};
+
+		if ( select_timeout.tv_sec > 0 ) {
+			select_timeout_ptr = &select_timeout;
+		}
+
+		result = sock_try_select( FD_SETSIZE, &rfds, &wfds, NULL, select_timeout_ptr );
+
+		if ( result == -1 ) {
+			warn( SHOW_ERRNO( "select() failed: " ) );
+			break;
+		}
+
+		/* Happens after failed reconnect. Avoid SIGBUS on FD_ISSET() */
+		if ( proxy->upstream_fd == -1 ) {
+			continue;
+		}
+
+		switch( state ) {
+			case READ_FROM_DOWNSTREAM:
+				if ( FD_ISSET( proxy->downstream_fd, &rfds ) ) {
+					state = proxy_read_from_downstream( proxy, state );
+					/* Check if we can fulfil the request from prefetch, or
+					 * rewrite the request to fill the prefetch buffer if needed
+					 */
+					if ( proxy_prefetches( proxy ) && state == WRITE_TO_UPSTREAM ) {
+						state = proxy_prefetch_for_request( proxy, state );
+					}
+				}
+				break;
+			case CONNECT_TO_UPSTREAM:
+				if ( FD_ISSET( proxy->upstream_fd, &wfds ) ) {
+					state = proxy_continue_connecting_to_upstream( proxy, state );
+				}
+				/* Leaving state untouched will retry connecting to upstream -
+				 * so introduce a bit of sleep  */
+				if ( state == CONNECT_TO_UPSTREAM ) {
+					connect_to_upstream_cooldown = 1;
+				}
+
+				break;
+			case READ_INIT_FROM_UPSTREAM:
+				state = proxy_read_init_from_upstream( proxy, state );
+
+				if ( state == CONNECT_TO_UPSTREAM ) {
+					connect_to_upstream_cooldown = 1;
+				}
+
+				break;
+			case WRITE_TO_UPSTREAM:
+				if ( FD_ISSET( proxy->upstream_fd, &wfds ) ) {
+					state = proxy_write_to_upstream( proxy, state );
+				}
+				break;
+			case READ_FROM_UPSTREAM:
+				if ( FD_ISSET( proxy->upstream_fd, &rfds ) ) {
+					state = proxy_read_from_upstream( proxy, state );
+				}
+				/* Fill the prefetch buffer and rewrite the reply, if needed */
+				if ( proxy_prefetches( proxy ) && state == WRITE_TO_DOWNSTREAM ) {
+					state = proxy_prefetch_for_reply( proxy, state );
+				}
+				break;
+			case WRITE_TO_DOWNSTREAM:
+				if ( FD_ISSET( proxy->downstream_fd, &wfds ) ) {
+					state = proxy_write_to_downstream( proxy, state );
+				}
+				break;
+		}
+
+		/* In these states, we're interested in restarting after a timeout.
+		 */
+		if ( old_state == state && proxy_state_upstream( state ) ) {
+			if ( ( monotonic_time_ms() ) - state_started > UPSTREAM_TIMEOUT ) {
+				warn(
+					"Timed out in state %s while communicating with upstream",
+					proxy_session_state_names[state]
+				);
+				state = CONNECT_TO_UPSTREAM;
+
+				/* Since we've timed out, we won't have gone through the timeout logic
+				 * in the various state handlers that resets these appropriately... */
+				proxy->init.size = 0;
+				proxy->init.needle = 0;
+				proxy->rsp.size = 0;
+				proxy->rsp.needle = 0;
+			}
+		}
+	}
+
+	info(
+		"Finished proxy session on fd %i after %"PRIu64" successful request(s)",
+		proxy->downstream_fd, proxy->req_count
+	);
+
+	/* Reset these two for the next session */
+	proxy->req_count = 0;
+	proxy->hello_sent = 0;
+
+	return;
+}
+
+/** Accept an NBD socket connection, dispatch appropriately */
+int proxy_accept( struct proxier* params )
+{
+	NULLCHECK( params );
+
+	int              client_fd;
+	fd_set           fds;
+
+	union mysockaddr client_address;
+	socklen_t        socklen = sizeof( client_address );
+
+	info( "Waiting for client connection" );
+
+	FD_ZERO(&fds);
+	FD_SET(params->listen_fd, &fds);
+
+	FATAL_IF_NEGATIVE(
+		sock_try_select(FD_SETSIZE, &fds, NULL, NULL, NULL),
+		SHOW_ERRNO( "select() failed" )
+	);
+
+	if ( FD_ISSET( params->listen_fd, &fds ) ) {
+		client_fd = accept( params->listen_fd, &client_address.generic, &socklen );
+
+		if ( client_address.family != AF_UNIX ) {
+			if ( sock_set_tcp_nodelay(client_fd, 1) == -1 ) {
+				warn( SHOW_ERRNO( "Failed to set TCP_NODELAY" ) );
+			}
+		}
+
+		info( "Accepted nbd client socket fd %d", client_fd );
+		sock_set_nonblock( client_fd, 1 );
+		params->downstream_fd = client_fd;
+		proxy_session( params );
+
+		WARN_IF_NEGATIVE(
+			sock_try_close( params->downstream_fd ),
+			"Couldn't close() downstram fd %i after proxy session",
+			params->downstream_fd
+		);
+		params->downstream_fd = -1;
+	}
+
+	return 1; /* We actually expect to be interrupted by signal handlers */
+}
+
+
+void proxy_accept_loop( struct proxier* params )
+{
+	NULLCHECK( params );
+	while( proxy_accept( params ) );
+}
+
+/** Closes sockets */
+void proxy_cleanup( struct proxier* proxy )
+{
+	NULLCHECK( proxy );
+
+	info( "Cleaning up" );
+
+	if ( -1 != proxy->listen_fd ) {
+
+		if ( AF_UNIX == proxy->listen_on.family ) {
+			if ( -1 == unlink( proxy->listen_on.un.sun_path ) ) {
+				warn( SHOW_ERRNO( "Failed to unlink %s", proxy->listen_on.un.sun_path ) );
+			}
+		}
+
+		WARN_IF_NEGATIVE(
+			sock_try_close( proxy->listen_fd ),
+			SHOW_ERRNO( "Failed to close() listen fd %i", proxy->listen_fd )
+		);
+		proxy->listen_fd = -1;
+	}
+
+	if ( -1 != proxy->downstream_fd ) {
+		WARN_IF_NEGATIVE(
+			sock_try_close( proxy->downstream_fd ),
+			SHOW_ERRNO(
+				"Failed to close() downstream fd %i", proxy->downstream_fd
+			)
+		);
+		proxy->downstream_fd = -1;
+	}
+
+	if ( -1 != proxy->upstream_fd ) {
+		WARN_IF_NEGATIVE(
+			sock_try_close( proxy->upstream_fd ),
+			SHOW_ERRNO(
+				"Failed to close() upstream fd %i", proxy->upstream_fd
+			)
+		);
+		proxy->upstream_fd = -1;
+	}
+
+	info( "Cleanup done" );
+}
+
+/** Full lifecycle of the proxier */
+int do_proxy( struct proxier* params )
+{
+	NULLCHECK( params );
+
+	info( "Ensuring upstream server is open" );
+
+	if ( !proxy_connect_to_upstream( params ) ) {
+		warn( "Couldn't connect to upstream server during initialization, exiting" );
+		proxy_cleanup( params );
+		return 1;
+	};
+
+	proxy_open_listen_socket( params );
+	proxy_accept_loop( params );
+	proxy_cleanup( params );
+
+	return 0;
+}
+

src/proxy/proxy.h

@@ -0,0 +1,97 @@
+#ifndef PROXY_H
+#define PROXY_H
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "ioutil.h"
+#include "parse.h"
+#include "nbdtypes.h"
+#include "self_pipe.h"
+
+#ifdef PREFETCH
+  #include "prefetch.h"
+#endif
+
+/** UPSTREAM_TIMEOUT
+ * How long ( in ms ) to allow for upstream to respond. If it takes longer
+ * than this, we will cancel the current request-response to them and resubmit
+ */
+#define UPSTREAM_TIMEOUT 30 * 1000
+
+struct proxier {
+	/** address/port to bind to */
+	union mysockaddr  listen_on;
+
+	/** address/port to connect to */
+	union mysockaddr  connect_to;
+
+	/** address to bind to when making outgoing connections */
+	union mysockaddr  connect_from;
+	int               bind; /* Set to true if we should use it */
+
+	/* The socket we listen() on and accept() against */
+	int               listen_fd;
+
+	/* The socket returned by accept() that we receive requests from and send
+	 * responses to
+	 */
+	int               downstream_fd;
+
+	/* The socket returned by connect() that we send requests to and receive
+	 * responses from
+	 */
+	int               upstream_fd;
+
+	/* This is the size we advertise to the downstream server */
+	uint64_t          upstream_size;
+
+	/* We transform the raw request header into here */
+	struct nbd_request req_hdr;
+
+    /* We transform the raw reply header into here */
+	struct nbd_reply   rsp_hdr;
+
+	/* Used for our non-blocking negotiation with upstream. TODO: maybe use
+	 * for downstream as well ( we currently overload rsp ) */
+	struct iobuf init;
+
+	/* The current NBD request from downstream */
+	struct iobuf req;
+
+	/* The current NBD reply from upstream */
+	struct iobuf rsp;
+
+	/* It's starting to feel like we need an object for a single proxy session.
+	 * These two track how many requests we've sent so far, and whether the
+	 * NBD_INIT code has been sent to the client yet.
+	 */
+	uint64_t req_count;
+	int hello_sent;
+
+	/** These are only used if we pass --cache on the command line */
+
+	/* While the in-flight request has been munged by prefetch, these two are
+	 * set to true, and the original length of the request, respectively */
+	int is_prefetch_req;
+	uint32_t prefetch_req_orig_len;
+
+	/* And here, we actually store the prefetched data once it's returned */
+	struct prefetch *prefetch;
+
+	/** */
+};
+
+struct proxier* proxy_create(
+	char* s_downstream_address,
+	char* s_downstream_port,
+	char* s_upstream_address,
+	char* s_upstream_port,
+	char* s_upstream_bind,
+	char* s_cache_bytes);
+int do_proxy( struct proxier* proxy );
+void proxy_cleanup( struct proxier* proxy );
+void proxy_destroy( struct proxier* proxy );
+
+#endif
+

src/readwrite.h

@@ -1,16 +0,0 @@
-#ifndef READWRITE_H
-
-#define READWRITE_H
-
-#include <sys/types.h>
-#include <sys/socket.h>
-
-int socket_connect(struct sockaddr* to, struct sockaddr* from);
-int socket_nbd_read_hello(int fd, off64_t * size);
-void socket_nbd_read(int fd, off64_t from, int len, int out_fd, void* out_buf, int timeout_secs);
-void socket_nbd_write(int fd, off64_t from, int len, int out_fd, void* out_buf, int timeout_secs);
-void socket_nbd_entrust(int fd);
-int socket_nbd_disconnect( int fd );
-
-#endif
-

src/serve.h

@@ -1,114 +0,0 @@
-#ifndef SERVE_H
-#define SERVE_H
-
-#include <sys/types.h>
-#include <unistd.h>
-
-#include "flexnbd.h"
-#include "parse.h"
-#include "acl.h"
-
-
-static const int block_allocation_resolution = 4096;//128<<10;
-
-
-struct client_tbl_entry {
-	pthread_t thread;
-	union mysockaddr address;
-	struct client * client;
-};
-
-
-#define MAX_NBD_CLIENTS 16
-struct server {
-	/* The flexnbd wrapper this server is attached to */
-	struct flexnbd * flexnbd;
-
-	/** address/port to bind to */
-	union mysockaddr     bind_to;
-	/** (static) file name to serve */
-	char*                filename;
-	/** file name of INCOMPLETE flag */
-	char*                filename_incomplete;
-	/** TCP backlog for listen() */
-	int                  tcp_backlog;
-	/** (static) file name of UNIX control socket (or NULL if none) */
-	char*                control_socket_name;
-	/** size of file */
-	uint64_t 	     size;
-
-	/** Claims around any I/O to this file */
-	struct flexthread_mutex * l_io;
-	
-	/** to interrupt accept loop and clients, write() to close_signal[1] */
-	struct self_pipe *   close_signal;
-
-	/** access control list */
-	struct acl *         acl;
-	/** acl_updated_signal will be signalled after the acl struct
-	 * has been replaced
-	 */
-	struct self_pipe *   acl_updated_signal;
-
-	/* Claimed around any updates to the ACL. */
-	struct flexthread_mutex *   l_acl;
-
-	struct mirror* mirror;
-	struct mirror_super * mirror_super; 
-	int                  server_fd;
-	int                  control_fd;
-	
-	struct bitset_mapping* allocation_map;
-	
-	int                  max_nbd_clients;
-	struct client_tbl_entry *nbd_client;
-
-
-	/* Marker for whether this server has control over the data in
-	 * the file, or if we're waiting to receive it from an inbound
-	 * migration which hasn't yet finished.
-	 */
-	int has_control;
-};
-
-struct server * server_create( 
-		struct flexnbd * flexnbd,
-		char* s_ip_address, 
-		char* s_port, 
-		char* s_file,
-		int default_deny,
-		int acl_entries, 
-		char** s_acl_entries,
-		int max_nbd_clients,
-		int has_control );
-void server_destroy( struct server * );
-int server_is_closed(struct server* serve);
-void server_dirty(struct server *serve, off64_t from, int len);
-void server_lock_io( struct server * serve);
-void server_unlock_io( struct server* serve );
-void serve_signal_close( struct server *serve );
-void serve_wait_for_close( struct server * serve );
-void server_replace_acl( struct server *serve, struct acl * acl);
-void server_control_arrived( struct server *serve );
-int server_is_in_control( struct server *serve );
-int server_default_deny( struct server * serve );
-int server_io_locked( struct server * serve );
-int server_acl_locked( struct server * serve );
-void server_lock_acl( struct server *serve );
-void server_unlock_acl( struct server *serve );
-
-
-int do_serve( struct server * );
-
-struct mode_readwrite_params {
-	union mysockaddr     connect_to;
-	union mysockaddr     connect_from;
-	off64_t              from;
-	off64_t              len;
-	int                  data_fd;
-	int                  client;
-};
-
-
-#endif
-

src/server/acl.c

@@ -31,7 +31,7 @@ static int is_included_in_acl(int list_length, struct ip_and_mask (*list)[], uni
 	for (i=0; i < list_length; i++) {
 		struct ip_and_mask *entry = &(*list)[i];
 		int testbits;
-		unsigned char *raw_address1, *raw_address2;
+		unsigned char *raw_address1 = NULL, *raw_address2 = NULL;
 
 		debug("checking acl entry %d (%d/%d)", i, test->generic.sa_family, entry->ip.family);
 

src/server/bitset.h

@@ -0,0 +1,438 @@
+#ifndef BITSET_H
+#define BITSET_H
+
+#include "util.h"
+
+#include <inttypes.h>
+#include <string.h>
+#include <pthread.h>
+
+/*
+ * Make the bitfield words 'opaque' to prevent code
+ * poking at the bits directly without using these
+ * accessors/macros
+ */
+typedef uint64_t	bitfield_word_t;
+typedef bitfield_word_t * bitfield_p;
+
+#define BITFIELD_WORD_SIZE	sizeof(bitfield_word_t)
+#define BITS_PER_WORD	(BITFIELD_WORD_SIZE * 8)
+
+#define BIT_MASK(_idx)	\
+			(1LL << ((_idx) & (BITS_PER_WORD - 1)))
+#define BIT_WORD(_b, _idx)	\
+			((bitfield_word_t*)(_b))[(_idx) / BITS_PER_WORD]
+
+/* Calculates the number of words needed to store _bytes number of bytes
+ * this is added to accommodate code that wants to use bytes sizes
+ */
+#define BIT_WORDS_FOR_SIZE(_bytes) \
+			((_bytes + (BITFIELD_WORD_SIZE-1)) / BITFIELD_WORD_SIZE)
+
+/** Return the bit value ''idx'' in array ''b'' */
+static inline int bit_get(bitfield_p b, uint64_t idx) {
+	return (BIT_WORD(b, idx) >> (idx & (BITS_PER_WORD-1))) & 1;
+}
+
+/** Return 1 if the bit at ''idx'' in array ''b'' is set */
+static inline int bit_is_set(bitfield_p b, uint64_t idx) {
+	return bit_get(b, idx);
+}
+/** Return 1 if the bit at ''idx'' in array ''b'' is clear */
+static inline int bit_is_clear(bitfield_p b, uint64_t idx) {
+	return !bit_get(b, idx);
+}
+/** Tests whether the bit at ''idx'' in array ''b'' has value ''value'' */
+static inline int bit_has_value(bitfield_p b, uint64_t idx, int value) {
+	return bit_get(b, idx) == !!value;
+}
+/** Sets the bit ''idx'' in array ''b'' */
+static inline void bit_set(bitfield_p b, uint64_t idx) {
+	BIT_WORD(b, idx) |= BIT_MASK(idx);
+}
+/** Clears the bit ''idx'' in array ''b'' */
+static inline void bit_clear(bitfield_p b, uint64_t idx) {
+	BIT_WORD(b, idx) &= ~BIT_MASK(idx);
+}
+/** Sets ''len'' bits in array ''b'' starting at offset ''from'' */
+static inline void bit_set_range(bitfield_p b, uint64_t from, uint64_t len)
+{
+	for ( ; (from % BITS_PER_WORD) != 0 && len > 0 ; len-- ) {
+		bit_set( b, from++ );
+	}
+
+	if (len >= BITS_PER_WORD) {
+		memset(&BIT_WORD(b, from), 0xff, len / 8 );
+		from += len;
+		len = len % BITS_PER_WORD;
+		from -= len;
+	}
+
+	for ( ; len > 0 ; len-- ) {
+		bit_set( b, from++ );
+	}
+}
+/** Clears ''len'' bits in array ''b'' starting at offset ''from'' */
+static inline void bit_clear_range(bitfield_p b, uint64_t from, uint64_t len)
+{
+	for ( ; (from % BITS_PER_WORD) != 0 && len > 0 ; len-- ) {
+		bit_clear( b, from++ );
+	}
+
+	if (len >= BITS_PER_WORD) {
+		memset(&BIT_WORD(b, from), 0, len / 8 );
+		from += len;
+		len = len % BITS_PER_WORD;
+		from -= len;
+	}
+
+	for ( ; len > 0 ; len-- ) {
+		bit_clear( b, from++ );
+	}
+}
+
+/** Counts the number of contiguous bits in array ''b'', starting at ''from''
+  * up to a maximum number of bits ''len''.  Returns the number of contiguous
+  * bits that are the same as the first one specified. If ''run_is_set'' is
+  * non-NULL, the value of that bit is placed into it.
+  */
+static inline uint64_t bit_run_count(bitfield_p b, uint64_t from, uint64_t len, int *run_is_set) {
+	uint64_t count = 0;
+	int first_value = bit_get(b, from);
+	bitfield_word_t word_match = first_value ? -1 : 0;
+
+	if ( run_is_set != NULL ) {
+		*run_is_set = first_value;
+	}
+
+	for ( ; ((from + count) % BITS_PER_WORD) != 0 && len > 0; len--) {
+		if (bit_has_value(b, from + count, first_value)) {
+			count++;
+		} else {
+			return count;
+		}
+	}
+
+	for ( ; len >= BITS_PER_WORD ; len -= BITS_PER_WORD ) {
+		if (BIT_WORD(b, from + count) == word_match) {
+			count += BITS_PER_WORD;
+		} else {
+			break;
+		}
+	}
+
+	for ( ; len > 0; len-- ) {
+		if ( bit_has_value(b, from + count, first_value) ) {
+			count++;
+		}
+	}
+
+	return count;
+}
+
+enum bitset_stream_events {
+  BITSET_STREAM_UNSET = 0,
+  BITSET_STREAM_SET = 1,
+  BITSET_STREAM_ON = 2,
+  BITSET_STREAM_OFF = 3
+};
+#define BITSET_STREAM_EVENTS_ENUM_SIZE 4
+
+struct bitset_stream_entry {
+	enum bitset_stream_events event;
+	uint64_t from;
+	uint64_t len;
+};
+
+/** Limit the stream size to 1MB for now.
+ *
+ *  If this is too small, it'll cause requests to stall as the migration lags
+ *  behind the changes made by those requests.
+ */
+#define BITSET_STREAM_SIZE ( ( 1024 * 1024 ) / sizeof( struct bitset_stream_entry ) )
+
+struct bitset_stream {
+	struct bitset_stream_entry entries[BITSET_STREAM_SIZE];
+	int in;
+	int out;
+	int size;
+	pthread_mutex_t mutex;
+	pthread_cond_t cond_not_full;
+	pthread_cond_t cond_not_empty;
+	uint64_t queued_bytes[BITSET_STREAM_EVENTS_ENUM_SIZE];
+};
+
+
+/** An application of a bitset - a bitset mapping represents a file of ''size''
+  * broken down into ''resolution''-sized chunks.  The bit set is assumed to
+  * represent one bit per chunk.  We also bundle a lock so that the set can be
+  * written reliably by multiple threads.
+  */
+struct bitset {
+	pthread_mutex_t lock;
+	uint64_t size;
+	int resolution;
+	struct bitset_stream *stream;
+	int stream_enabled;
+	bitfield_word_t bits[];
+};
+
+/** Allocate a bitset for a file of the given size, and chunks of the
+  * given resolution.
+  */
+static inline struct bitset *bitset_alloc( uint64_t size, int resolution )
+{
+	// calculate a size to allocate that is a multiple of the size of the
+	// bitfield word
+	size_t bitfield_size =
+			BIT_WORDS_FOR_SIZE((( size + resolution - 1 ) / resolution)) * sizeof( bitfield_word_t );
+	struct bitset *bitset = xmalloc(sizeof( struct bitset ) + ( bitfield_size / 8 ) );
+
+	bitset->size = size;
+	bitset->resolution = resolution;
+	/* don't actually need to call pthread_mutex_destroy '*/
+	pthread_mutex_init(&bitset->lock, NULL);
+	bitset->stream = xmalloc( sizeof( struct bitset_stream ) );
+	pthread_mutex_init( &bitset->stream->mutex, NULL );
+
+	/* Technically don't need to call pthread_cond_destroy either */
+	pthread_cond_init( &bitset->stream->cond_not_full, NULL );
+	pthread_cond_init( &bitset->stream->cond_not_empty, NULL );
+
+	return bitset;
+}
+
+static inline void bitset_free( struct bitset * set )
+{
+	/* TODO: free our mutex... */
+
+	free( set->stream );
+	set->stream = NULL;
+
+	free( set );
+}
+
+#define INT_FIRST_AND_LAST \
+  uint64_t first = from/set->resolution, \
+      last = ((from+len)-1)/set->resolution, \
+      bitlen = (last-first)+1
+
+#define BITSET_LOCK \
+  FATAL_IF_NEGATIVE(pthread_mutex_lock(&set->lock), "Error locking bitset")
+
+#define BITSET_UNLOCK \
+  FATAL_IF_NEGATIVE(pthread_mutex_unlock(&set->lock), "Error unlocking bitset")
+
+
+static inline void bitset_stream_enqueue(
+	struct bitset * set,
+	enum bitset_stream_events event,
+	uint64_t from,
+	uint64_t len
+)
+{
+	struct bitset_stream * stream = set->stream;
+
+	pthread_mutex_lock( &stream->mutex );
+
+	while ( stream->size == BITSET_STREAM_SIZE ) {
+		pthread_cond_wait( &stream->cond_not_full, &stream->mutex );
+	}
+
+	stream->entries[stream->in].event = event;
+	stream->entries[stream->in].from = from;
+	stream->entries[stream->in].len = len;
+	stream->queued_bytes[event] += len;
+
+	stream->size++;
+	stream->in++;
+	stream->in %= BITSET_STREAM_SIZE;
+
+	pthread_mutex_unlock( & stream->mutex );
+	pthread_cond_signal( &stream->cond_not_empty );
+
+	return;
+}
+
+static inline void bitset_stream_dequeue(
+	struct bitset * set,
+	struct bitset_stream_entry * out
+)
+{
+	struct bitset_stream * stream = set->stream;
+	struct bitset_stream_entry * dequeued;
+
+	pthread_mutex_lock( &stream->mutex );
+
+	while ( stream->size == 0 ) {
+		pthread_cond_wait( &stream->cond_not_empty, &stream->mutex );
+	}
+
+	dequeued = &stream->entries[stream->out];
+
+	if ( out != NULL ) {
+		out->event = dequeued->event;
+		out->from  = dequeued->from;
+		out->len   = dequeued->len;
+	}
+
+	stream->queued_bytes[dequeued->event] -= dequeued->len;
+	stream->size--;
+	stream->out++;
+	stream->out %= BITSET_STREAM_SIZE;
+
+	pthread_mutex_unlock( &stream->mutex );
+	pthread_cond_signal( &stream->cond_not_full );
+
+	return;
+}
+
+static inline size_t bitset_stream_size( struct bitset * set )
+{
+	size_t size;
+
+	pthread_mutex_lock( &set->stream->mutex );
+	size = set->stream->size;
+	pthread_mutex_unlock( &set->stream->mutex );
+
+	return size;
+}
+
+static inline uint64_t bitset_stream_queued_bytes(
+	struct bitset * set,
+	enum bitset_stream_events event
+)
+{
+	uint64_t total;
+
+	pthread_mutex_lock( &set->stream->mutex );
+	total = set->stream->queued_bytes[event];
+	pthread_mutex_unlock( &set->stream->mutex );
+
+	return total;
+}
+
+static inline void bitset_enable_stream( struct bitset * set )
+{
+	BITSET_LOCK;
+	set->stream_enabled = 1;
+	bitset_stream_enqueue( set, BITSET_STREAM_ON, 0, set->size );
+	BITSET_UNLOCK;
+}
+
+static inline void bitset_disable_stream( struct bitset * set  )
+{
+	BITSET_LOCK;
+	bitset_stream_enqueue( set, BITSET_STREAM_OFF, 0, set->size );
+	set->stream_enabled = 0;
+	BITSET_UNLOCK;
+}
+
+/** Set the bits in a bitset which correspond to the given bytes in the larger
+  * file.
+  */
+static inline void bitset_set_range(
+	struct bitset * set,
+	uint64_t from,
+	uint64_t len)
+{
+	INT_FIRST_AND_LAST;
+	BITSET_LOCK;
+	bit_set_range(set->bits, first, bitlen);
+
+	if ( set->stream_enabled ) {
+		bitset_stream_enqueue( set, BITSET_STREAM_SET, from, len );
+	}
+
+	BITSET_UNLOCK;
+}
+
+
+/** Set every bit in the bitset. */
+static inline void bitset_set( struct bitset * set )
+{
+	bitset_set_range(set, 0, set->size);
+}
+
+/** Clear the bits in a bitset which correspond to the given bytes in the
+  * larger file.
+  */
+static inline void bitset_clear_range(
+	struct bitset * set,
+	uint64_t from,
+	uint64_t len)
+{
+	INT_FIRST_AND_LAST;
+	BITSET_LOCK;
+	bit_clear_range(set->bits, first, bitlen);
+
+	if ( set->stream_enabled ) {
+		bitset_stream_enqueue( set, BITSET_STREAM_UNSET, from, len );
+	}
+
+	BITSET_UNLOCK;
+}
+
+
+/** Clear every bit in the bitset. */
+static inline void bitset_clear( struct bitset * set )
+{
+	bitset_clear_range(set, 0, set->size);
+}
+
+/** As per bitset_run_count but also tells you whether the run it found was set
+  * or unset, atomically.
+  */
+static inline uint64_t bitset_run_count_ex(
+	struct bitset * set,
+	uint64_t from,
+	uint64_t len,
+	int* run_is_set
+)
+{
+	uint64_t run;
+
+	/* Clip our requests to the end of the bitset,  avoiding uint underflow. */
+	if ( from > set->size ) {
+		return 0;
+	}
+	len = ( len + from ) > set->size ? ( set->size - from ) : len;
+
+	INT_FIRST_AND_LAST;
+
+	BITSET_LOCK;
+	run = bit_run_count(set->bits, first, bitlen, run_is_set) * set->resolution;
+	run -= (from % set->resolution);
+	BITSET_UNLOCK;
+
+	return run;
+}
+
+/** Counts the number of contiguous bytes that are represented as a run in
+  * the bit field.
+  */
+static inline uint64_t bitset_run_count(
+	struct bitset * set,
+	uint64_t from,
+	uint64_t len)
+{
+	return bitset_run_count_ex( set, from, len, NULL );
+}
+
+/** Tests whether the bit field is clear for the given file offset.
+  */
+static inline int bitset_is_clear_at( struct bitset * set, uint64_t at )
+{
+	return bit_is_clear(set->bits, at/set->resolution);
+}
+
+/** Tests whether the bit field is set for the given file offset.
+  */
+static inline int bitset_is_set_at( struct bitset * set, uint64_t at )
+{
+	return bit_is_set(set->bits, at/set->resolution);
+}
+
+
+#endif
+

src/server/client.c

@@ -1,12 +1,12 @@
 #include "client.h"
 #include "serve.h"
-#include "util.h"
 #include "ioutil.h"
+#include "sockutil.h"
+#include "util.h"
 #include "bitset.h"
 #include "nbdtypes.h"
 #include "self_pipe.h"
 
-
 #include <sys/mman.h>
 #include <errno.h>
 #include <stdlib.h>
@@ -16,25 +16,49 @@
 #include <fcntl.h>
 
 
+// When this signal is invoked, we call shutdown() on the client fd, which
+// results in the thread being wound up
+void client_killswitch_hit(int signal __attribute__ ((unused)), siginfo_t *info, void *ptr __attribute__ ((unused)))
+{
+	int fd = info->si_value.sival_int;
+	warn( "Killswitch for fd %i activated, calling shutdown on socket", fd );
 
-
+	FATAL_IF(
+		-1 == shutdown( fd, SHUT_RDWR ),
+		SHOW_ERRNO( "Failed to shutdown() the socket, killing the server" )
+	 );
+}
 
 struct client *client_create( struct server *serve, int socket )
 {
 	NULLCHECK( serve );
 
 	struct client *c;
+	struct sigevent evp = {
+		.sigev_notify = SIGEV_SIGNAL,
+		.sigev_signo = CLIENT_KILLSWITCH_SIGNAL
+	};
 
-	c = xmalloc( sizeof( struct server ) );
+	/*
+	 * Our killswitch closes this socket, forcing read() and write() calls
+	 * blocked on it to return with an error. The thread then close()s the
+	 * socket itself, avoiding races.
+	 */
+	evp.sigev_value.sival_int = socket;
+
+	c = xmalloc( sizeof( struct client ) );
 	c->stopped = 0;
 	c->socket = socket;
 	c->serve = serve;
 
 	c->stop_signal = self_pipe_create();
 
-	c->entrusted = 0;
+	FATAL_IF_NEGATIVE(
+		timer_create( CLOCK_MONOTONIC, &evp, &(c->killswitch) ),
+		SHOW_ERRNO( "Failed to create killswitch timer" )
+	);
 
-	debug( "Alloced client %p (%d, %d)", c, c->stop_signal->read_fd, c->stop_signal->write_fd );
+	debug( "Alloced client %p with socket %d", c, socket );
 	return c;
 }
 
@@ -51,8 +75,14 @@ void client_destroy( struct client *client )
 {
 	NULLCHECK( client );
 
+	FATAL_IF_NEGATIVE(
+		timer_delete( client->killswitch ),
+		SHOW_ERRNO( "Couldn't delete killswitch" )
+	);
+
 	debug( "Destroying stop signal for client %p", client );
 	self_pipe_destroy( client->stop_signal );
+	debug( "Freeing client %p", client );
 	free( client );
 }
 
@@ -61,20 +91,22 @@ void client_destroy( struct client *client )
 /**
  * So waiting on client->socket is len bytes of data, and we must write it all
  * to client->mapped.  However while doing do we must consult the bitmap
- * client->block_allocation_map, which is a bitmap where one bit represents
- * block_allocation_resolution bytes.  Where a bit isn't set, there are no 
+ * client->serve->allocation_map, which is a bitmap where one bit represents
+ * block_allocation_resolution bytes.  Where a bit isn't set, there are no
  * disc blocks allocated for that portion of the file, and we'd like to keep
- * it that way.  
+ * it that way.
  *
  * If the bitmap shows that every block in our prospective write is already
- * allocated, we can proceed as normal and make one call to writeloop.  
- * 
+ * allocated, we can proceed as normal and make one call to writeloop.
+ *
  */
-void write_not_zeroes(struct client* client, uint64_t from, int len)
+void write_not_zeroes(struct client* client, uint64_t from, uint64_t len)
 {
 	NULLCHECK( client );
+	NULLCHECK( client->serve );
+	NULLCHECK( client->serve->allocation_map );
 
-	struct bitset_mapping *map = client->serve->allocation_map;
+	struct bitset * map = client->serve->allocation_map;
 
 	while (len > 0) {
 		/* so we have to calculate how much of our input to consider
@@ -84,30 +116,34 @@ void write_not_zeroes(struct client* client, uint64_t from, int len)
 		 * how many blocks our write covers, then cut off the start
 		 * and end to get the exact number of bytes.
 		 */
-		 
-		int run = bitset_run_count(map, from, len);
-		
+
+		uint64_t run = bitset_run_count(map, from, len);
+		struct iommap *iommap = iommap_alloc(client->fileno, from, len); 
+
 		debug("write_not_zeroes: from=%ld, len=%d, run=%d", from, len, run);
-		
+
 		if (run > len) {
 			run = len;
 			debug("(run adjusted to %d)", run);
 		}
-		
-		if (0) /* useful but expensive */
+
+		/* 
+		// Useful but expensive
+		if (0) 
 		{
 			uint64_t i;
 			fprintf(stderr, "full map resolution=%d: ", map->resolution);
 			for (i=0; i<client->serve->size; i+=map->resolution) {
 				int here = (from >= i && from < i+map->resolution);
-				
+
 				if (here) { fprintf(stderr, ">"); }
 				fprintf(stderr, bitset_is_set_at(map, i) ? "1" : "0");
 				if (here) { fprintf(stderr, "<"); }
 			}
 			fprintf(stderr, "\n");
 		}
-		
+		*/
+
 		#define DO_READ(dst, len) ERROR_IF_NEGATIVE( \
 			readloop( \
 				client->socket, \
@@ -116,12 +152,17 @@ void write_not_zeroes(struct client* client, uint64_t from, int len)
 			), \
 			"read failed %ld+%d", from, (len) \
 		)
-		
+
 		if (bitset_is_set_at(map, from)) {
 			debug("writing the lot: from=%ld, run=%d", from, run);
 			/* already allocated, just write it all */
-			DO_READ(client->mapped + from, run);
-			server_dirty(client->serve, from, run);
+			DO_READ(iommap->buf, run);
+			/* We know from our earlier call to  bitset_run_count that the
+			 * bitset is all-1s at this point, but we need to dirty it for the
+			 * sake of the event stream - the actual bytes have changed, and we
+			 * are interested in that fact.
+			 */
+			bitset_set_range( map, from, run );
 			len  -= run;
 			from += run;
 		}
@@ -129,36 +170,44 @@ void write_not_zeroes(struct client* client, uint64_t from, int len)
 			char zerobuffer[block_allocation_resolution];
 			/* not allocated, read in block_allocation_resoution */
 			while (run > 0) {
-				int blockrun = block_allocation_resolution - 
+				uint64_t blockrun = block_allocation_resolution -
 				  (from % block_allocation_resolution);
 				if (blockrun > run)
 					blockrun = run;
-				
+
 				DO_READ(zerobuffer, blockrun);
-				
-				/* This reads the buffer twice in the worst case 
+
+				/* This reads the buffer twice in the worst case
 				 * but we're leaning on memcmp failing early
 				 * and memcpy being fast, rather than try to
 				 * hand-optimized something specific.
 				 */
-				if (zerobuffer[0] != 0 || 
-				    memcmp(zerobuffer, zerobuffer + 1, blockrun - 1)) {
-					memcpy(client->mapped+from, zerobuffer, blockrun);
+
+				int all_zeros = (zerobuffer[0] == 0) &&
+					(0 == memcmp( zerobuffer, zerobuffer+1, blockrun-1 ));
+
+				if ( !all_zeros ) {
+					memcpy(iommap->buf, zerobuffer, blockrun);
 					bitset_set_range(map, from, blockrun);
-					server_dirty(client->serve, from, blockrun);
 					/* at this point we could choose to
 					 * short-cut the rest of the write for
 					 * faster I/O but by continuing to do it
-					 * the slow way we preserve as much 
+					 * the slow way we preserve as much
 					 * sparseness as possible.
 					 */
 				}
+				/* When the block is all_zeroes, no bytes have changed, so we
+				 * don't need to put an event into the bitset stream. This may
+				 * be surprising in the future.
+				 */
 
 				len  -= blockrun;
 				run  -= blockrun;
 				from += blockrun;
 			}
 		}
+		iommap_sync(iommap);
+		iommap_free(iommap);
 	}
 }
 
@@ -177,31 +226,6 @@ int client_read_request( struct client * client , struct nbd_request *out_reques
 	NULLCHECK( out_request );
 
 	struct nbd_request_raw request_raw;
-	fd_set                 fds;
-	struct timeval         tv = {CLIENT_MAX_WAIT_SECS, 0};
-	struct timeval *       ptv;
-	int                    fd_count;
-
-	/* We want a timeout if this is an inbound migration, but not
-	 * otherwise
-	 */
-	ptv = server_is_in_control( client->serve ) ? NULL : &tv;
-	
-	FD_ZERO(&fds);
-	FD_SET(client->socket, &fds);
-	self_pipe_fd_set( client->stop_signal, &fds );
-	fd_count = select(FD_SETSIZE, &fds, NULL, NULL, ptv);
-	if ( fd_count == 0 ) {
-		/* This "can't ever happen" */
-		if ( NULL == ptv ) { fatal( "No FDs selected, and no timeout!" ); } 
-		else { error("Timed out waiting for I/O"); }
-	}
-	else if ( fd_count < 0 ) { fatal( "Select failed" ); }
-	
-	if ( self_pipe_fd_isset( client->stop_signal, &fds ) ){
-		debug("Client received stop signal.");
-		return 0;
-	}
 
 	if (fd_read_request(client->socket, &request_raw) == -1) {
 		*disconnected = 1;
@@ -213,6 +237,10 @@ int client_read_request( struct client * client , struct nbd_request *out_reques
 				debug( "Connection reset while"
 						" reading request" );
 				return 0;
+			case ETIMEDOUT:
+				debug( "Connection timed out while"
+						" reading request" );
+				return 0;
 			default:
 				/* FIXME: I've seen this happen, but I
 				 * couldn't reproduce it so I'm leaving
@@ -221,29 +249,29 @@ int client_read_request( struct client * client , struct nbd_request *out_reques
 				 * again.  It should *probably* be an
 				 * error() call, but I want to be sure.
 				 * */
-				fatal("Error reading request: %d, %s", 
-						errno, 
-						strerror( errno )); 
+				fatal("Error reading request: %d, %s",
+						errno,
+						strerror( errno ));
 		}
 	}
 
 	nbd_r2h_request( &request_raw, out_request );
-
 	return 1;
 }
 
-int fd_write_reply( int fd, char *handle, int error )
+int fd_write_reply( int fd, uint64_t handle, int error )
 {
 	struct nbd_reply     reply;
 	struct nbd_reply_raw reply_raw;
 
 	reply.magic = REPLY_MAGIC;
 	reply.error = error;
-	memcpy( reply.handle, handle, 8 );
+	reply.handle.w = handle;
 
 	nbd_h2r_reply( &reply, &reply_raw );
+	debug( "Replying with handle=0x%08X, error=%"PRIu32, handle, error );
 
-	if( -1 == write( fd, &reply_raw, sizeof( reply_raw ) ) ) {
+	if( -1 == writeloop( fd, &reply_raw, sizeof( reply_raw ) ) ) {
 		switch( errno ) {
 			case ECONNRESET:
 				error( "Connection reset while writing reply" );
@@ -270,7 +298,7 @@ int fd_write_reply( int fd, char *handle, int error )
  */
 int client_write_reply( struct client * client, struct nbd_request *request, int error )
 {
-	return fd_write_reply( client->socket, request->handle, error);
+	return fd_write_reply( client->socket, request->handle.w, error);
 }
 
 
@@ -279,7 +307,7 @@ void client_write_init( struct client * client, uint64_t size )
 	struct nbd_init init = {{0}};
 	struct nbd_init_raw init_raw = {{0}};
 
-	memcpy( init.passwd, INIT_PASSWD, sizeof( INIT_PASSWD ) );
+	memcpy( init.passwd, INIT_PASSWD, sizeof( init.passwd ) );
 	init.magic = INIT_MAGIC;
 	init.size = size;
 	memset( init.reserved, 0, 128 );
@@ -300,7 +328,7 @@ void client_write_init( struct client * client, uint64_t size )
 void client_flush( struct client * client, size_t len )
 {
 	int devnull = open("/dev/null", O_WRONLY);
-	FATAL_IF_NEGATIVE( devnull, 
+	FATAL_IF_NEGATIVE( devnull,
 			"Couldn't open /dev/null: %s", strerror(errno));
 	int pipes[2];
 	pipe( pipes );
@@ -309,9 +337,9 @@ void client_flush( struct client * client, size_t len )
 	size_t spliced = 0;
 
 	while ( spliced < len ) {
-		ssize_t received = splice( 
+		ssize_t received = splice(
 				client->socket, NULL,
-				pipes[1], NULL, 
+				pipes[1], NULL,
 				len-spliced, flags );
 		FATAL_IF_NEGATIVE( received,
 				"splice error: %s",
@@ -319,9 +347,9 @@ void client_flush( struct client * client, size_t len )
 		ssize_t junked = 0;
 		while( junked < received ) {
 			ssize_t junk;
-			junk = splice( 
+			junk = splice(
 				pipes[0], NULL,
-				devnull, NULL, 
+				devnull, NULL,
 				received, flags );
 			FATAL_IF_NEGATIVE( junk,
 				"splice error: %s",
@@ -341,78 +369,66 @@ void client_flush( struct client * client, size_t len )
  * Returns 1 if we do, 0 otherwise.
  * request_err is set to 0 if the client sent a bad request, in which
  * case we drop the connection.
- * FIXME: after an ENTRUST, there's no way to distinguish between a
- * DISCONNECT and any bad request.
  */
-int client_request_needs_reply( struct client * client, 
+int client_request_needs_reply( struct client * client,
 		struct nbd_request request )
 {
-	debug("request type %d", request.type);
-	
+	/* The client is stupid, but don't take down the whole server as a result.
+	 * We send a reply before disconnecting so that at least some indication of
+	 * the problem is visible, and so proxies don't retry the same (bad) request
+	 * forever.
+	 */
 	if (request.magic != REQUEST_MAGIC) {
-		fatal("Bad magic %08x", request.magic);
+		warn("Bad magic 0x%08X from client", request.magic);
+		client_write_reply( client, &request, EBADMSG );
+		client->disconnect = 1; // no need to flush
+		return 0;
 	}
-		
+
+	debug(
+		"request type=%"PRIu32", from=%"PRIu64", len=%"PRIu32", handle=0x%08X",
+		request.type, request.from, request.len, request.handle
+	);
+
+	/* check it's not out of range */
+	if ( request.from+request.len > client->serve->size) {
+		warn("write request %"PRIu64"+%"PRIu32" out of range",
+		  request.from, request.len
+		);
+		if ( request.type == REQUEST_WRITE ) {
+			client_flush( client, request.len );
+		}
+		client_write_reply( client, &request, EPERM ); /* TODO: Change to ERANGE ? */
+		client->disconnect = 0;
+		return 0;
+	}
+
+
 	switch (request.type)
 	{
 	case REQUEST_READ:
-		ERROR_IF( client->entrusted,
-				"Received a read request "
-				"after an entrust message.");
 		break;
 	case REQUEST_WRITE:
-		ERROR_IF( client->entrusted,
-				"Received a write request "
-				"after an entrust message.");
-		/* check it's not out of range */
-		if ( request.from+request.len > client->serve->size) {
-			warn("write request %d+%d out of range",
-			  request.from, 
-			  request.len
-			);
-			client_write_reply( client, &request, 1 );
-			client_flush( client, request.len );
-			client->disconnect = 0;
-			return 0;
-		}
-		break;
-		
-	case REQUEST_ENTRUST:
-		/* Yes, we need to reply to an entrust, but we take no
-		 * further action */
-		debug("request entrust");
 		break;
 	case REQUEST_DISCONNECT:
 		debug("request disconnect");
 		client->disconnect = 1;
 		return 0;
-		
+
 	default:
-		fatal("Unknown request %08x", request.type);
+		fatal("Unknown request 0x%08X", request.type);
 	}
 	return 1;
 }
 
 
-void client_reply_to_entrust( struct client * client, struct nbd_request request )
-{
-	/* An entrust needs a response, but has no data. */
-	debug( "request entrust" );
-
-	client_write_reply( client, &request, 0 );
-	/* We set this after trying to send the reply, so we know the
-	 * reply got away safely.
-	 */
-	client->entrusted = 1;
-}
-
-
 void client_reply_to_read( struct client* client, struct nbd_request request )
 {
 	off64_t offset;
 
 	debug("request read %ld+%d", request.from, request.len);
-	client_write_reply( client, &request, 0);
+	sock_set_tcp_cork( client->socket, 1 );
+	client_write_reply( client, &request, 0 );
 
 	offset = request.from;
 
@@ -421,50 +437,50 @@ void client_reply_to_read( struct client* client, struct nbd_request request )
 	 */
 	ERROR_IF_NEGATIVE(
 			sendfileloop(
-				client->socket, 
-				client->fileno, 
-				&offset, 
+				client->socket,
+				client->fileno,
+				&offset,
 				request.len),
 			"sendfile failed from=%ld, len=%d",
 			offset,
 			request.len);
+
+	sock_set_tcp_cork( client->socket, 0 );
 }
 
 
 void client_reply_to_write( struct client* client, struct nbd_request request )
 {
-	debug("request write %ld+%d", request.from, request.len);
-	if (client->serve->allocation_map) {
+	debug("request write from=%"PRIu64", len=%"PRIu32", handle=0x%08X", request.from, request.len, request.handle);
+	// TODO: Just write directly for now.  Not (yet) convinced my changes later on work.
+	// if (client->serve->allocation_map_built) {
+	if (0) {
 		write_not_zeroes( client, request.from, request.len );
 	}
 	else {
 		debug("No allocation map, writing directly.");
-		/* If we get cut off partway through reading this data
+		/* If we get cut off partway through reading this data:
 		 * */
+		struct iommap *iommap = iommap_alloc(client->fileno, request.from, request.len); 
+
 		ERROR_IF_NEGATIVE(
 			readloop( client->socket,
-				client->mapped + request.from,
+				iommap->buf,
 				request.len),
 			"reading write data failed from=%ld, len=%d",
 			request.from,
-			request.len 
+			request.len
 		);
-		server_dirty(client->serve, request.from, request.len);
+
+		iommap_sync(iommap);
+		iommap_free(iommap);
+		/* the allocation_map is shared between client threads, and may be
+		 * being built. We need to reflect the write in it, as it may be in
+		 * a position the builder has already gone over.
+		 */
+		bitset_set_range(client->serve->allocation_map, request.from, request.len);
 	}
 
-	if (1) /* not sure whether this is necessary... */
-	{
-		/* multiple of 4K page size */
-		uint64_t from_rounded = request.from & (!0xfff);
-		uint64_t len_rounded = request.len + (request.from - from_rounded);
-
-		FATAL_IF_NEGATIVE(
-			msync( client->mapped + from_rounded, 
-				len_rounded, 
-				MS_SYNC),
-			"msync failed %ld %ld", request.from, request.len
-		);
-	}
 	client_write_reply( client, &request, 0);
 }
 
@@ -478,36 +494,135 @@ void client_reply( struct client* client, struct nbd_request request )
 	case REQUEST_WRITE:
 		client_reply_to_write( client, request );
 		break;
-	case REQUEST_ENTRUST:
-		client_reply_to_entrust( client, request );
-		break;
 	}
 }
 
 
+/* Starts a timer that will kill the whole process if disarm is not called
+ * within a timeout (see CLIENT_HANDLE_TIMEOUT).
+ */
+void client_arm_killswitch( struct client* client )
+{
+	struct itimerspec its = {
+		.it_value    = { .tv_nsec = 0, .tv_sec = CLIENT_HANDLER_TIMEOUT },
+		.it_interval = { .tv_nsec = 0, .tv_sec = 0 }
+	};
+
+	if ( !client->serve->use_killswitch ) {
+		return;
+	}
+
+	debug( "Arming killswitch" );
+
+	FATAL_IF_NEGATIVE(
+		timer_settime( client->killswitch, 0, &its, NULL ),
+		SHOW_ERRNO( "Failed to arm killswitch" )
+	);
+
+	return;
+}
+
+void client_disarm_killswitch( struct client* client )
+{
+	struct itimerspec its = {
+		.it_value    = { .tv_nsec = 0, .tv_sec = 0 },
+		.it_interval = { .tv_nsec = 0, .tv_sec = 0 }
+	};
+
+	if ( !client->serve->use_killswitch ) {
+		return;
+	}
+
+	debug( "Disarming killswitch" );
+
+	FATAL_IF_NEGATIVE(
+		timer_settime( client->killswitch, 0, &its, NULL ),
+		SHOW_ERRNO( "Failed to disarm killswitch" )
+	);
+
+	return;
+}
+
 /* Returns 0 if we should continue trying to serve requests */
 int client_serve_request(struct client* client)
 {
 	struct nbd_request    request = {0};
-	int                   failure = 1;
+	int                   stop = 1;
 	int                   disconnected = 0;
+	fd_set                rfds, efds;
+	int                   fd_count;
 
-	if ( !client_read_request( client, &request, &disconnected ) ) { return failure; }
-	if ( disconnected ) { return failure; }
-	if ( !client_request_needs_reply( client, request ) )  {
+	/* wait until there are some bytes on the fd before committing to reads
+	 * FIXME: this whole scheme is broken because we're using blocking reads.
+	 * read() can block directly after a select anyway, and it's possible that,
+	 * without the killswitch, we'd hang forever. With the killswitch, we just
+	 * hang for "a while". The Right Thing to do is to rewrite client.c to be
+	 * non-blocking.
+	 */
+
+	FD_ZERO( &rfds );
+	FD_SET( client->socket, &rfds );
+	self_pipe_fd_set( client->stop_signal, &rfds );
+
+	FD_ZERO( &efds );
+	FD_SET( client->socket, &efds );
+
+	fd_count = sock_try_select( FD_SETSIZE, &rfds, NULL, &efds, NULL );
+
+	if ( fd_count == 0 ) {
+		/* This "can't ever happen" */
+		fatal( "No FDs selected, and no timeout!" );
+	}
+	else if ( fd_count < 0 ) { fatal( "Select failed" ); }
+
+	if ( self_pipe_fd_isset( client->stop_signal, &rfds ) ){
+		debug("Client received stop signal.");
+		return 1; // Don't try to serve more requests
+	}
+
+	if ( FD_ISSET( client->socket, &efds ) ) {
+		debug( "Client connection closed" );
+		return 1;
+	}
+
+
+	/* We arm / disarm around the whole request cycle. The reason for this is
+	 * that the remote peer could uncleanly die at any point; if we're stuck on
+	 * a blocking read(), then that will hang for (almost) forever. This is bad
+	 * in general, makes the server respond only to kill -9, and breaks
+	 * outward mirroring in a most unpleasant way.
+	 *
+	 * Don't forget to disarm before exiting, no matter what!
+	 *
+	 * The replication is simple: open a connection to the flexnbd server, write
+	 * a single byte, and then wait.
+	 *
+	 */
+	client_arm_killswitch( client );
+
+	if ( !client_read_request( client, &request, &disconnected ) ) {
+		client_disarm_killswitch( client );
+		return stop;
+	}
+	if ( disconnected ) {
+		client_disarm_killswitch( client );
+		return stop;
+	}
+
+	if ( !client_request_needs_reply( client, request ) ) {
+		client_disarm_killswitch( client );
 		return client->disconnect;
-	} 
+	}
 
-	server_lock_io( client->serve );
 	{
 		if ( !server_is_closed( client->serve ) ) {
 			client_reply( client, request );
-			failure = 0;
+			stop = 0;
 		}
 	}
-	server_unlock_io( client->serve );
 
-	return failure;
+	client_disarm_killswitch( client );
+	return stop;
 }
 
 
@@ -516,18 +631,29 @@ void client_send_hello(struct client* client)
 	client_write_init( client, client->serve->size );
 }
 
-void client_cleanup(struct client* client, 
+void client_cleanup(struct client* client,
 		int fatal __attribute__ ((unused)) )
 {
 	info("client cleanup for client %p", client);
-	
-	if (client->socket) { close(client->socket); }
-	if (client->mapped) {
-		munmap(client->mapped, client->serve->size);
-	}
-	if (client->fileno) { close(client->fileno); }
 
-	if ( server_io_locked( client->serve ) ) { server_unlock_io( client->serve ); }
+	/* If the thread hits an error, we need to ensure this is off */
+	client_disarm_killswitch( client );
+
+	if (client->socket) {
+		FATAL_IF_NEGATIVE( close(client->socket),
+			"Error closing client socket %d",
+			client->socket );
+		debug("Closed client socket fd %d", client->socket);
+		client->socket = -1;
+	}
+	if (client->fileno) {
+		FATAL_IF_NEGATIVE( close(client->fileno),
+			"Error closing file %d",
+			client->fileno );
+		debug("Closed client file fd %d", client->fileno );
+		client->fileno = -1;
+	}
+
 	if ( server_acl_locked( client->serve ) ) { server_unlock_acl( client->serve ); }
 
 }
@@ -535,47 +661,39 @@ void client_cleanup(struct client* client,
 void* client_serve(void* client_uncast)
 {
 	struct client* client = (struct client*) client_uncast;
-	
+	void** a = NULL;
+
 	error_set_handler((cleanup_handler*) client_cleanup, client);
-	
 	info("client: mmaping file");
 	FATAL_IF_NEGATIVE(
 		open_and_mmap(
 			client->serve->filename,
 			&client->fileno,
-			NULL, 
-			(void**) &client->mapped
+			NULL,
+			a
 		),
 		"Couldn't open/mmap file %s: %s", client->serve->filename, strerror( errno )
 	);
+
+	debug( "Opened client file fd %d", client->fileno);
 	debug("client: sending hello");
 	client_send_hello(client);
-	
+
 	debug("client: serving requests");
 	while (client_serve_request(client) == 0)
 		;
 	debug("client: stopped serving requests");
 	client->stopped = 1;
-		
-	if ( client->entrusted ) {
-		if ( client->disconnect ){
-			debug("client: control arrived" );
-			server_control_arrived( client->serve );
-		}
-		else {
-			warn( "client: control transfer failed." );
-		}
+
+	if ( client->disconnect ){
+		debug("client: control arrived" );
+		server_control_arrived( client->serve );
 	}
 
-	FATAL_IF_NEGATIVE(
-		close(client->socket),
-		"Couldn't close socket %d", 
-		client->socket
-	);
-	
 	debug("Cleaning client %p up normally in thread %p", client, pthread_self());
 	client_cleanup(client, 0);
 	debug("Client thread done" );
-	
+
 	return NULL;
 }
+

src/server/client.h

@@ -1,13 +1,20 @@
 #ifndef CLIENT_H
 #define CLIENT_H
 
-/** CLIENT_MAX_WAIT_SECS
- * This is the length of time an inbound migration will wait for a fresh
- * write before assuming the source has Gone Away.  Note: it is *not*
- * the time from one write to the next, it is the gap between the end of
- * one write and the start of the next.
+#include <signal.h>
+#include <time.h>
+
+/** CLIENT_HANDLER_TIMEOUT
+ * This is the length of time (in seconds) any request can be outstanding for.
+ * If we spend longer than this in a request, the whole server is killed.
  */
-#define CLIENT_MAX_WAIT_SECS 5
+#define CLIENT_HANDLER_TIMEOUT 120
+
+/** CLIENT_KILLSWITCH_SIGNAL
+ * The signal number we use to kill the server when *any* killswitch timer
+ * fires. The handler gets the fd of the client socket to work with.
+ */
+#define CLIENT_KILLSWITCH_SIGNAL ( SIGRTMIN + 1 )
 
 
 struct client {
@@ -20,21 +27,24 @@ struct client {
 	 */
 	int     stopped;
 	int     socket;
-	
+
 	int     fileno;
-	char*   mapped;
 
 	struct self_pipe * stop_signal;
-	
-	struct server* serve; /* FIXME: remove above duplication */
 
-	/* Have we seen a REQUEST_ENTRUST message? */
-	int     entrusted;
+	struct server* serve; /* FIXME: remove above duplication */
 
 	/* Have we seen a REQUEST_DISCONNECT message? */
 	int     disconnect;
+
+	/* kill the whole server if a request has been outstanding too long,
+	 * assuming use_killswitch is set in serve
+	 */
+	timer_t killswitch;
+
 };
 
+void client_killswitch_hit(int signal, siginfo_t *info, void *ptr);
 
 void* client_serve(void* client_uncast);
 struct client * client_create( struct server * serve, int socket );
@@ -42,3 +52,4 @@ void client_destroy( struct client * client );
 void client_signal_stop( struct client * client );
 
 #endif
+

src/server/control.c

@@ -21,7 +21,7 @@
  *  by a blank line (i.e. double LF).  The first line is taken to be the command
  *  name to invoke, and the lines before the double LF are its arguments.
  *
- *  These commands can be invoked remotely from the command line, with the 
+ *  These commands can be invoked remotely from the command line, with the
  *  client code to be found in remote.c
  */
 
@@ -45,7 +45,7 @@
 
 
 struct control * control_create(
-		struct flexnbd * flexnbd, 
+		struct flexnbd * flexnbd,
 		const char * csn)
 {
 	struct control * control = xmalloc( sizeof( struct control ) );
@@ -54,9 +54,10 @@ struct control * control_create(
 
 	control->flexnbd = flexnbd;
 	control->socket_name = csn;
+	control->open_signal = self_pipe_create();
 	control->close_signal = self_pipe_create();
 	control->mirror_state_mbox = mbox_create();
-	
+
 	return control;
 }
 
@@ -75,21 +76,22 @@ void control_destroy( struct control * control )
 
 	mbox_destroy( control->mirror_state_mbox );
 	self_pipe_destroy( control->close_signal );
+	self_pipe_destroy( control->open_signal );
 	free( control );
 }
 
-struct control_client * control_client_create( 
-		struct flexnbd * flexnbd, 
+struct control_client * control_client_create(
+		struct flexnbd * flexnbd,
 		int client_fd ,
 		struct mbox * state_mbox )
 {
 	NULLCHECK( flexnbd );
 
-	struct control_client * control_client = 
+	struct control_client * control_client =
 		xmalloc( sizeof( struct control_client ) );
 
 	control_client->socket = client_fd;
-	control_client->flexnbd = flexnbd; 
+	control_client->flexnbd = flexnbd;
 	control_client->mirror_state_mbox = state_mbox;
 	return control_client;
 }
@@ -110,7 +112,7 @@ void control_handle_client( struct control * control, int client_fd )
 	NULLCHECK( control );
 	NULLCHECK( control->flexnbd );
 	struct control_client * control_client =
-		control_client_create( 
+		control_client_create(
 				control->flexnbd,
 				client_fd ,
 				control->mirror_state_mbox);
@@ -152,7 +154,7 @@ int control_accept( struct control * control )
 	if ( self_pipe_fd_isset( control->close_signal, &fds ) ){
 		return 0;
 	}
-	
+
 	if ( FD_ISSET( control->control_fd, &fds ) ) {
 		control_accept_client( control );
 	}
@@ -170,27 +172,27 @@ int open_control_socket( const char * socket_name )
 {
 	struct sockaddr_un bind_address;
 	int control_fd;
-	
-	if (!socket_name) { 
+
+	if (!socket_name) {
 		fatal( "Tried to open a control socket without a socket name" );
 	}
 
 	control_fd = socket(AF_UNIX, SOCK_STREAM, 0);
 	FATAL_IF_NEGATIVE(control_fd ,
 	  "Couldn't create control socket");
-	
+
 	memset(&bind_address, 0, sizeof(struct sockaddr_un));
 	bind_address.sun_family = AF_UNIX;
 	strncpy(bind_address.sun_path, socket_name, sizeof(bind_address.sun_path)-1);
-	
+
 	//unlink(socket_name); /* ignore failure */
-	
+
 	FATAL_IF_NEGATIVE(
 		bind(control_fd , &bind_address, sizeof(bind_address)),
 		"Couldn't bind control socket to %s: %s",
 		socket_name, strerror( errno )
 	);
-	
+
 	FATAL_IF_NEGATIVE(
 		listen(control_fd , 5),
 		"Couldn't listen on control socket"
@@ -205,17 +207,30 @@ void control_listen(struct control* control)
 	control->control_fd = open_control_socket( control->socket_name );
 }
 
+void control_wait_for_open_signal( struct control * control )
+{
+	fd_set fds;
+	FD_ZERO( &fds );
+	self_pipe_fd_set( control->open_signal, &fds );
+	FATAL_IF_NEGATIVE( select( FD_SETSIZE, &fds, NULL, NULL, NULL ),
+			   "select() failed" );
+
+	self_pipe_signal_clear( control->open_signal );
+}
+
 
 void control_serve( struct control * control )
 {
 	NULLCHECK( control );
+
+	control_wait_for_open_signal( control );
 	control_listen( control );
 	while( control_accept( control ) );
 }
 
 
-void control_cleanup( 
-		struct control * control, 
+void control_cleanup(
+		struct control * control,
 		int fatal __attribute__((unused)) )
 {
 	NULLCHECK( control );
@@ -235,7 +250,7 @@ void * control_runner( void * control_uncast )
 	control_serve( control );
 
 	control_cleanup( control, 0 );
-	return NULL;
+	pthread_exit( NULL );
 }
 
 
@@ -260,6 +275,9 @@ void control_write_mirror_response( enum mirror_state mirror_state, int client_f
 		case MS_FAIL_SIZE_MISMATCH:
 			write_socket( "1: Remote size does not match local size" );
 			break;
+		case MS_ABANDONED:
+			write_socket( "1: Mirroring abandoned" );
+			break;
 		case MS_GO:
 		case MS_DONE: /* Yes, I know we know better, but it's simpler this way */
 			write_socket( "0: Mirror started" );
@@ -272,7 +290,7 @@ void control_write_mirror_response( enum mirror_state mirror_state, int client_f
 
 
 /* Call this in the thread where you want to receive the mirror state */
-enum mirror_state control_client_mirror_wait( 
+enum mirror_state control_client_mirror_wait(
 		struct control_client* client)
 {
 	NULLCHECK( client );
@@ -281,18 +299,17 @@ enum mirror_state control_client_mirror_wait(
 	struct mbox * mbox = client->mirror_state_mbox;
 	enum mirror_state mirror_state;
 	enum mirror_state * contents;
-	
+
 	contents = (enum mirror_state*)mbox_receive( mbox );
 	NULLCHECK( contents );
-	
+
 	mirror_state = *contents;
-	
+
 	free( contents );
-	
+
 	return mirror_state;
 }
 
-
 #define write_socket(msg) write(client->socket, (msg "\n"), strlen((msg))+1)
 /** Command parser to start mirror process from socket input */
 int control_mirror(struct control_client* client, int linesc, char** lines)
@@ -302,11 +319,11 @@ int control_mirror(struct control_client* client, int linesc, char** lines)
 	struct flexnbd * flexnbd = client->flexnbd;
 	union mysockaddr *connect_to = xmalloc( sizeof( union mysockaddr ) );
 	union mysockaddr *connect_from = NULL;
-	uint64_t max_Bps = 0;
+	uint64_t max_Bps = UINT64_MAX;
 	int action_at_finish;
 	int raw_port;
-	
-	
+
+
 	if (linesc < 2) {
 		write_socket("1: mirror takes at least two parameters");
 		return -1;
@@ -316,7 +333,7 @@ int control_mirror(struct control_client* client, int linesc, char** lines)
 		write_socket("1: bad IP address");
 		return -1;
 	}
-	
+
 	raw_port = atoi(lines[1]);
 	if (raw_port < 0 || raw_port > 65535) {
 		write_socket("1: bad IP port number");
@@ -324,22 +341,15 @@ int control_mirror(struct control_client* client, int linesc, char** lines)
 	}
 	connect_to->v4.sin_port = htobe16(raw_port);
 
-	if (linesc > 2) {
-		connect_from = xmalloc( sizeof( union mysockaddr ) );
-		if (parse_ip_to_sockaddr(&connect_from->generic, lines[2]) == 0) {
-			write_socket("1: bad bind address");
-			return -1;
-		}
-	}
-
-	if (linesc > 3) { max_Bps = atoi(lines[2]); }
-	
 	action_at_finish = ACTION_EXIT;
-	if (linesc > 4) {
-		if (strcmp("exit", lines[3]) == 0) {
+	if (linesc > 2) {
+		if (strcmp("exit", lines[2]) == 0) {
 			action_at_finish = ACTION_EXIT;
 		}
-		else if (strcmp("nothing", lines[3]) == 0) {
+		else if (strcmp( "unlink", lines[2]) == 0 ) {
+			action_at_finish = ACTION_UNLINK;
+		}
+		else if (strcmp("nothing", lines[2]) == 0) {
 			action_at_finish = ACTION_NOTHING;
 		}
 		else {
@@ -347,54 +357,121 @@ int control_mirror(struct control_client* client, int linesc, char** lines)
 			return -1;
 		}
 	}
-	
+
+	if (linesc > 3) {
+		connect_from = xmalloc( sizeof( union mysockaddr ) );
+		if (parse_ip_to_sockaddr(&connect_from->generic, lines[3]) == 0) {
+			write_socket("1: bad bind address");
+			return -1;
+		}
+	}
+
+	if (linesc > 4) {
+		errno = 0;
+		max_Bps = strtoull( lines[4], NULL, 10 );
+		if ( errno == ERANGE ) {
+			write_socket( "1: max_bps out of range" );
+			return -1;
+		} else if ( errno != 0 ) {
+			write_socket( "1: max_bps couldn't be parsed" );
+			return -1;
+		}
+	}
+
+
 	if (linesc > 5) {
 		write_socket("1: unrecognised parameters to mirror");
 		return -1;
 	}
 
-	/* In theory, we should never have to worry about the switch
-	 * lock here, since we should never be able to start more than
-	 * one mirror at a time.  This is enforced by only accepting a
-	 * single client at a time on the control socket.
-	 */
-	flexnbd_lock_switch( flexnbd );
-	{
-		struct server * serve = flexnbd_server(flexnbd);
-		serve->mirror_super = mirror_super_create( 
-				serve->filename,
-				connect_to,
-				connect_from,
-				max_Bps ,
-				action_at_finish,
-				client->mirror_state_mbox );
-		serve->mirror = serve->mirror_super->mirror;
+	struct server * serve = flexnbd_server(flexnbd);
 
+	server_lock_start_mirror( serve );
+	{
+		if ( server_mirror_can_start( serve ) ) {
+			serve->mirror_super = mirror_super_create(
+					serve->filename,
+					connect_to,
+					connect_from,
+					max_Bps ,
+					action_at_finish,
+					client->mirror_state_mbox );
+			serve->mirror = serve->mirror_super->mirror;
+			server_prevent_mirror_start( serve );
+		} else {
+			if ( serve->mirror_super ) {
+				warn( "Tried to start a second mirror run" );
+				write_socket( "1: mirror already running" );
+			} else {
+				warn( "Cannot start mirroring, shutting down" );
+				write_socket( "1: shutting down" );
+			}
+		}
+
+	}
+	server_unlock_start_mirror( serve );
+
+	/* Do this outside the lock to minimise the length of time the
+	 * sighandler can block the serve thread
+	 */
+	if ( serve->mirror_super ) {
 		FATAL_IF( 0 != pthread_create(
-					&serve->mirror_super->thread, 
-					NULL, 
-					mirror_super_runner, 
+					&serve->mirror_super->thread,
+					NULL,
+					mirror_super_runner,
 					serve
 					),
 				"Failed to create mirror thread"
 			);
 
 		debug("Control thread mirror super waiting");
-		enum mirror_state state =  
+		enum mirror_state state =
 			control_client_mirror_wait( client );
 		debug("Control thread writing response");
 		control_write_mirror_response( state, client->socket );
 	}
-	debug( "Control thread unlocking switch" );
-	flexnbd_unlock_switch( flexnbd );
+
 	debug( "Control thread going away." );
-	
+
+	return 0;
+}
+
+int control_mirror_max_bps( struct control_client* client, int linesc, char** lines )
+{
+	NULLCHECK( client );
+	NULLCHECK( client->flexnbd );
+
+	struct server* serve = flexnbd_server( client->flexnbd );
+	uint64_t max_Bps;
+
+	if ( !serve->mirror_super ) {
+		write_socket( "1: Not currently mirroring" );
+		return -1;
+	}
+
+	if ( linesc != 1 ) {
+		write_socket( "1: Bad format" );
+		return -1;
+	}
+
+	errno = 0;
+	max_Bps = strtoull( lines[0], NULL, 10 );
+	if ( errno == ERANGE ) {
+		write_socket( "1: max_bps out of range" );
+		return -1;
+	} else if ( errno != 0 ) {
+		write_socket( "1: max_bps couldn't be parsed" );
+		return -1;
+	}
+
+	serve->mirror->max_bytes_per_second = max_Bps;
+	write_socket( "0: updated" );
+
 	return 0;
 }
 
 #undef write_socket
 
-
 /** Command parser to alter access control list from socket input */
 int control_acl(struct control_client* client, int linesc, char** lines)
 {
@@ -406,31 +483,79 @@ int control_acl(struct control_client* client, int linesc, char** lines)
 	struct acl * new_acl = acl_create( linesc, lines, default_deny );
 
 	if (new_acl->len != linesc) {
+		warn("Bad ACL spec: %s", lines[new_acl->len] );
 		write(client->socket, "1: bad spec: ", 13);
-		write(client->socket, lines[new_acl->len], 
+		write(client->socket, lines[new_acl->len],
 				strlen(lines[new_acl->len]));
 		write(client->socket, "\n", 1);
 		acl_destroy( new_acl );
 	}
 	else {
 		flexnbd_replace_acl( flexnbd, new_acl );
-		write( client->socket, "0: updated", 10);
+		info("ACL set");
+		write( client->socket, "0: updated\n", 11);
 	}
 
 	return 0;
 }
 
+
+int control_break(
+		struct control_client* client,
+		int linesc __attribute__ ((unused)),
+		char** lines __attribute__((unused))
+		)
+{
+	NULLCHECK( client );
+	NULLCHECK( client->flexnbd );
+
+	int result = 0;
+	struct flexnbd* flexnbd = client->flexnbd;
+
+	struct server * serve = flexnbd_server( flexnbd );
+
+	server_lock_start_mirror( serve );
+	{
+		if ( server_is_mirroring( serve ) ) {
+
+			info( "Signaling to abandon mirror" );
+			server_abandon_mirror( serve );
+			debug( "Abandon signaled" );
+
+			if ( server_is_closed( serve ) ) {
+				info( "Mirror completed while canceling" );
+				write( client->socket,
+						"1: mirror completed\n", 20 );
+			}
+			else {
+				info( "Mirror successfully stopped." );
+				write( client->socket,
+						"0: mirror stopped\n", 18 );
+				result = 1;
+			}
+
+		} else {
+			warn( "Not mirroring." );
+			write( client->socket, "1: not mirroring\n", 17 );
+		}
+	}
+	server_unlock_start_mirror( serve );
+
+	return result;
+}
+
+
 /** FIXME: add some useful statistics */
 int control_status(
-		struct control_client* client, 
-		int linesc __attribute__ ((unused)), 
+		struct control_client* client,
+		int linesc __attribute__ ((unused)),
 		char** lines __attribute__((unused))
 		)
 {
 	NULLCHECK( client );
 	NULLCHECK( client->flexnbd );
 	struct status * status = flexnbd_status_create( client->flexnbd );
-	
+
 	write( client->socket, "0: ", 3 );
 	status_write( status, client->socket );
 	status_destroy( status );
@@ -438,15 +563,13 @@ int control_status(
 	return 0;
 }
 
-void control_client_cleanup(struct control_client* client, 
+void control_client_cleanup(struct control_client* client,
 		int fatal __attribute__ ((unused)) )
 {
 	if (client->socket) { close(client->socket); }
 
 	/* This is wrongness */
-	if ( server_io_locked( client->flexnbd->serve ) ) { server_unlock_io( client->flexnbd->serve ); }
 	if ( server_acl_locked( client->flexnbd->serve ) ) { server_unlock_acl( client->flexnbd->serve ); }
-	if ( flexnbd_switch_locked( client->flexnbd ) ) { flexnbd_unlock_switch( client->flexnbd ); }
 
 	control_client_destroy( client );
 }
@@ -458,7 +581,7 @@ void control_respond(struct control_client * client)
 
 	error_set_handler((cleanup_handler*) control_client_cleanup, client);
 
-	int i, linesc;		
+	int i, linesc;
 	linesc = read_lines_until_blankline(client->socket, 256, &lines);
 
 	if (linesc < 1)
@@ -478,11 +601,22 @@ void control_respond(struct control_client * client)
 			debug("mirror command failed");
 		}
 	}
+	else if (strcmp(lines[0], "break") == 0) {
+		info( "break command received" );
+		if ( control_break( client, linesc-1, lines+1) < 0) {
+			debug( "break command failed" );
+		}
+	}
 	else if (strcmp(lines[0], "status") == 0) {
 		info("status command received" );
 		if (control_status(client, linesc-1, lines+1) < 0) {
 			debug("status command failed");
 		}
+	} else if ( strcmp( lines[0], "mirror_max_bps" ) == 0 ) {
+		info( "mirror_max_bps command received" );
+		if( control_mirror_max_bps( client, linesc-1, lines+1 ) < 0 ) {
+			debug( "mirror_max_bps command failed" );
+		}
 	}
 	else {
 		write(client->socket, "10: unknown command\n", 23);

src/server/control.h

@@ -1,10 +1,14 @@
 #ifndef CONTROL_H
 #define CONTROL_H
 
+/* We need this to avoid a complaint about struct server * in
+ * void accept_control_connection
+ */
+struct server;
 
 #include "parse.h"
 #include "mirror.h"
-#include "control.h"
+#include "serve.h"
 #include "flexnbd.h"
 #include "mbox.h"
 
@@ -14,7 +18,8 @@ struct control {
 	const char * socket_name;
 
 	pthread_t thread;
-	
+
+	struct self_pipe * open_signal;
 	struct self_pipe * close_signal;
 
 	/* This is owned by the control object, and used by a
@@ -32,7 +37,7 @@ struct control {
 struct control_client{
 	int              socket;
 	struct flexnbd * flexnbd;
-	
+
 	/* Passed in on creation.  We know it's all right to do this
 	 * because we know there's only ever one control_client.
 	 */
@@ -40,7 +45,7 @@ struct control_client{
 };
 
 struct control * control_create(
-		struct flexnbd *, 
+		struct flexnbd *,
 		const char * control_socket_name );
 void control_signal_close( struct control * );
 void control_destroy( struct control * );

src/server/flexnbd.c

@@ -21,7 +21,6 @@
 
 #include "flexnbd.h"
 #include "serve.h"
-#include "listen.h"
 #include "util.h"
 #include "control.h"
 #include "status.h"
@@ -52,7 +51,7 @@ int flexnbd_build_signal_fd(void)
 	sigaddset( &mask, SIGQUIT );
 	sigaddset( &mask, SIGINT );
 
-	FATAL_UNLESS( 0 == pthread_sigmask( SIG_BLOCK, &mask, NULL ), 
+	FATAL_UNLESS( 0 == pthread_sigmask( SIG_BLOCK, &mask, NULL ),
 			"Signal blocking failed" );
 
 	sfd = signalfd( -1, &mask, 0 );
@@ -63,12 +62,12 @@ int flexnbd_build_signal_fd(void)
 
 
 void flexnbd_create_shared(
-	struct flexnbd * flexnbd, 
+	struct flexnbd * flexnbd,
 	const char * s_ctrl_sock)
 {
 	NULLCHECK( flexnbd );
 	if ( s_ctrl_sock ){
-		flexnbd->control = 
+		flexnbd->control =
 			control_create( flexnbd, s_ctrl_sock );
 	}
 	else {
@@ -76,8 +75,6 @@ void flexnbd_create_shared(
 	}
 
 	flexnbd->signal_fd = flexnbd_build_signal_fd();
-
-	flexnbd->switch_mutex = flexthread_mutex_create();
 }
 
 
@@ -85,57 +82,69 @@ struct flexnbd * flexnbd_create_serving(
 	char* s_ip_address,
 	char* s_port,
 	char* s_file,
-	char *s_ctrl_sock,
+	char* s_ctrl_sock,
 	int default_deny,
 	int acl_entries,
 	char** s_acl_entries,
-	int max_nbd_clients)
+	int max_nbd_clients,
+	int use_killswitch)
 {
 	struct flexnbd * flexnbd = xmalloc( sizeof( struct flexnbd ) );
-	flexnbd->serve = server_create( 
+	flexnbd->serve = server_create(
 			flexnbd,
 			s_ip_address,
 			s_port,
-			s_file, 
-			default_deny,
-			acl_entries,
-			s_acl_entries,
-			max_nbd_clients, 
-			1);
-	flexnbd_create_shared( flexnbd, s_ctrl_sock );
-	return flexnbd;
-}
-
-
-struct flexnbd * flexnbd_create_listening(
-		char* s_ip_address, 
-		char* s_rebind_ip_address, 
-		char* s_port, 
-		char* s_rebind_port, 
-		char* s_file,
-		char *s_ctrl_sock, 
-		int default_deny,
-		int acl_entries, 
-		char** s_acl_entries,
-		int max_nbd_clients )
-{
-	struct flexnbd * flexnbd = xmalloc( sizeof( struct flexnbd ) );
-	flexnbd->listen = listen_create(
-			flexnbd,
-			s_ip_address,
-			s_rebind_ip_address,
-			s_port,
-			s_rebind_port,
 			s_file,
 			default_deny,
 			acl_entries,
 			s_acl_entries,
-			max_nbd_clients);
-	flexnbd->serve = flexnbd->listen->init_serve;
+			max_nbd_clients,
+			use_killswitch,
+			1);
 	flexnbd_create_shared( flexnbd, s_ctrl_sock );
+
+	// Beats installing one handler per client instance
+	if ( use_killswitch ) {
+		struct sigaction act = {
+			.sa_sigaction = client_killswitch_hit,
+			.sa_flags = SA_RESTART | SA_SIGINFO
+		};
+
+		FATAL_UNLESS(
+			0 == sigaction( CLIENT_KILLSWITCH_SIGNAL, &act, NULL ),
+			"Installing client killswitch signal failed"
+		);
+	}
+
 	return flexnbd;
 }
 
+struct flexnbd * flexnbd_create_listening(
+		char* s_ip_address,
+		char* s_port,
+		char* s_file,
+		char* s_ctrl_sock,
+		int default_deny,
+		int acl_entries,
+		char** s_acl_entries )
+{
+	struct flexnbd * flexnbd = xmalloc( sizeof( struct flexnbd ) );
+	flexnbd->serve = server_create(
+			flexnbd,
+			s_ip_address,
+			s_port,
+			s_file,
+			default_deny,
+			acl_entries,
+			s_acl_entries,
+			1, 0, 0);
+	flexnbd_create_shared( flexnbd, s_ctrl_sock );
+
+	// listen can't use killswitch, as mirror may pause on sending things
+	// for a very long time.
+
+	return flexnbd;
+}
 
 void flexnbd_spawn_control(struct flexnbd * flexnbd )
 {
@@ -144,10 +153,10 @@ void flexnbd_spawn_control(struct flexnbd * flexnbd )
 
 	pthread_t * control_thread = &flexnbd->control->thread;
 
-	FATAL_UNLESS( 0 == pthread_create( 
-				control_thread, 
-				NULL, 
-				control_runner, 
+	FATAL_UNLESS( 0 == pthread_create(
+				control_thread,
+				NULL,
+				control_runner,
 				flexnbd->control ),
 			"Couldn't create the control thread" );
 }
@@ -158,8 +167,10 @@ void flexnbd_stop_control( struct flexnbd * flexnbd )
 	NULLCHECK( flexnbd->control );
 
 	control_signal_close( flexnbd->control );
-	FATAL_UNLESS( 0 == pthread_join( flexnbd->control->thread, NULL ),
-			"Failed joining the control thread" );
+	pthread_t tid = flexnbd->control->thread;
+	FATAL_UNLESS( 0 == pthread_join( tid, NULL ),
+		      "Failed joining the control thread" );
+	debug( "Control thread %p pthread_join returned", tid );
 }
 
 
@@ -175,52 +186,22 @@ void flexnbd_destroy( struct flexnbd * flexnbd )
 	if ( flexnbd->control ) {
 		control_destroy( flexnbd->control );
 	}
-	if ( flexnbd->listen ) {
-		listen_destroy( flexnbd->listen );
-	}
-
-	flexthread_mutex_destroy( flexnbd->switch_mutex );
 
 	close( flexnbd->signal_fd );
 	free( flexnbd );
 }
 
 
-/* THOU SHALT NOT DEREFERENCE flexnbd->serve OUTSIDE A SWITCH LOCK
- */
-void flexnbd_lock_switch( struct flexnbd * flexnbd )
-{
-	NULLCHECK( flexnbd );
-	flexthread_mutex_lock( flexnbd->switch_mutex );
-}
-
-void flexnbd_unlock_switch( struct flexnbd * flexnbd )
-{
-	NULLCHECK( flexnbd );
-	flexthread_mutex_unlock( flexnbd->switch_mutex );
-}
-
-int flexnbd_switch_locked( struct flexnbd * flexnbd )
-{
-	NULLCHECK( flexnbd );
-	return flexthread_mutex_held( flexnbd->switch_mutex );
-}
-
 struct server * flexnbd_server( struct flexnbd * flexnbd )
 {
 	NULLCHECK( flexnbd );
 	return flexnbd->serve;
 }
 
-
 void flexnbd_replace_acl( struct flexnbd * flexnbd, struct acl * acl )
 {
 	NULLCHECK( flexnbd );
-	flexnbd_lock_switch( flexnbd );
-	{
-		server_replace_acl( flexnbd_server(flexnbd), acl );
-	}
-	flexnbd_unlock_switch( flexnbd );
+	server_replace_acl( flexnbd_server(flexnbd), acl );
 }
 
 
@@ -228,17 +209,11 @@ struct status * flexnbd_status_create( struct flexnbd * flexnbd )
 {
 	NULLCHECK( flexnbd );
 	struct status * status;
-	
-	flexnbd_lock_switch( flexnbd );
-	{
-		status = status_create( flexnbd_server( flexnbd ) );
-	}
-	flexnbd_unlock_switch( flexnbd );
+
+	status = status_create( flexnbd_server( flexnbd ) );
 	return status;
 }
 
-/** THOU SHALT *ONLY* CALL THIS FROM INSIDE A SWITCH LOCK
- */
 void flexnbd_set_server( struct flexnbd * flexnbd, struct server * serve )
 {
 	NULLCHECK( flexnbd );
@@ -246,40 +221,21 @@ void flexnbd_set_server( struct flexnbd * flexnbd, struct server * serve )
 }
 
 
-/* Calls the given callback to exchange server objects, then sets
- * flexnbd->server so everything else can see it. */
-void flexnbd_switch( struct flexnbd * flexnbd, struct server *(listen_cb)(struct listen *) )
-{
-	NULLCHECK( flexnbd );
-	NULLCHECK( flexnbd->listen );
-
-	flexnbd_lock_switch( flexnbd );
-	{
-		struct server * new_server = listen_cb( flexnbd->listen );
-		NULLCHECK( new_server );
-		flexnbd_set_server( flexnbd, new_server );
-	}
-	flexnbd_unlock_switch( flexnbd );
-
-}
-
-/* Get the default_deny of the current server object.  This takes the
- * switch_lock to avoid nastiness if the server switches and gets freed
- * in the dereference chain.
- * This means that this function must not be called if the switch lock
- * is already held.
- */
+/* Get the default_deny of the current server object. */
 int flexnbd_default_deny( struct flexnbd * flexnbd )
 {
-	int result;
-
 	NULLCHECK( flexnbd );
-	flexnbd_lock_switch( flexnbd );
-	{
-		result = server_default_deny( flexnbd->serve );
-	}
-	flexnbd_unlock_switch( flexnbd );
-	return result;
+	return server_default_deny( flexnbd->serve );
+}
+
+
+void make_writable( const char * filename )
+{
+	NULLCHECK( filename );
+	FATAL_IF_NEGATIVE( chmod( filename, S_IWUSR ),
+			"Couldn't chmod %s: %s",
+			filename,
+			strerror( errno ) );
 }
 
 
@@ -287,22 +243,16 @@ int flexnbd_serve( struct flexnbd * flexnbd )
 {
 	NULLCHECK( flexnbd );
 	int success;
+	struct self_pipe * open_signal = NULL;
 
 	if ( flexnbd->control ){
 		debug( "Spawning control thread" );
 		flexnbd_spawn_control( flexnbd );
+		open_signal = flexnbd->control->open_signal;
 	}
 
-	if ( flexnbd->listen ){
-		success = do_listen( flexnbd->listen );
-	}
-	else {
-		do_serve( flexnbd->serve );
-		/* We can't tell here what the intent was.  We can
-		 * legitimately exit either in control or not.
-		 */
-		success = 1;
-	}
+	success = do_serve( flexnbd->serve, open_signal );
+	debug("do_serve success is %d", success );
 
 	if ( flexnbd->control ) {
 		debug( "Stopping control thread" );

src/server/flexnbd.h

@@ -4,7 +4,8 @@
 #include "acl.h"
 #include "mirror.h"
 #include "serve.h"
-#include "listen.h"
+#include "proxy.h"
+#include "client.h"
 #include "self_pipe.h"
 #include "mbox.h"
 #include "control.h"
@@ -12,66 +13,54 @@
 
 /* Carries the "globals". */
 struct flexnbd {
-
-	/* We always have a serve pointer, but it should never be
-	 * dereferenced outside a flexnbd_switch_lock/unlock pair.
+	/* Our serve pointer should never be dereferenced outside a
+	 * flexnbd_switch_lock/unlock pair.
 	 */
 	struct server * serve;
-	/* We only have a listen object if the process was started in
-	 * listen mode.
-	 */
-	struct listen * listen;
+
 	/* We only have a control object if a control socket name was
 	 * passed on the command line.
 	 */
 	struct control * control;
 
-	/* switch_mutex is the lock around dereferencing the serve
-	 * pointer.
-	 */
-	struct flexthread_mutex * switch_mutex;
-
 	/* File descriptor for a signalfd(2) signal stream. */
 	int signal_fd;
 };
 
+
 struct flexnbd * flexnbd_create(void);
 struct flexnbd * flexnbd_create_serving(
 	char* s_ip_address,
 	char* s_port,
 	char* s_file,
-	char *s_ctrl_sock,
+	char* s_ctrl_sock,
 	int default_deny,
 	int acl_entries,
 	char** s_acl_entries,
-	int max_nbd_clients);
+	int max_nbd_clients,
+	int use_killswitch);
 
 struct flexnbd * flexnbd_create_listening(
-		char* s_ip_address, 
-		char* s_rebind_ip_address, 
-		char* s_port, 
-		char* s_rebind_port, 
-		char* s_file,
-		char *s_ctrl_sock, 
-		int default_deny,
-		int acl_entries, 
-		char** s_acl_entries,
-		int max_nbd_clients );
+	char* s_ip_address,
+	char* s_port,
+	char* s_file,
+	char* s_ctrl_sock,
+	int default_deny,
+	int acl_entries,
+	char** s_acl_entries );
 
 void flexnbd_destroy( struct flexnbd * );
 enum mirror_state;
 enum mirror_state flexnbd_get_mirror_state( struct flexnbd * );
-void flexnbd_lock_switch( struct flexnbd * );
-void flexnbd_unlock_switch( struct flexnbd * );
-int flexnbd_switch_locked( struct flexnbd * );
 int flexnbd_default_deny( struct flexnbd * );
 void flexnbd_set_server( struct flexnbd * flexnbd, struct server * serve );
-void flexnbd_switch( struct flexnbd * flexnbd, struct server *(listen_cb)(struct listen *) );
 int flexnbd_signal_fd( struct flexnbd * flexnbd );
 
 
 int flexnbd_serve( struct flexnbd * flexnbd );
+int flexnbd_proxy( struct flexnbd * flexnbd );
 struct server * flexnbd_server( struct flexnbd * flexnbd );
 void flexnbd_replace_acl( struct flexnbd * flexnbd, struct acl * acl );
 struct status * flexnbd_status_create( struct flexnbd * flexnbd );
 #endif
+

src/server/mirror.h

@@ -18,6 +18,18 @@ enum mirror_state;
  */
 #define MS_CONNECT_TIME_SECS 60
 
+/* MS_MAX_DOWNTIME_SECS
+ * The length of time a migration must be estimated to have remaining for us to
+ * disconnect clients for convergence
+ *
+ * TODO: Make this configurable so refusing-to-converge clients can be manually
+ *       fixed.
+ * TODO: Make this adaptive - 5 seconds is fine, as long as we can guarantee
+ *       that all migrations will be able to converge in time. We'd add a new
+ *       state between open and closed, where gradually-increasing latency is
+ *       added to client requests to allow the mirror to be faster.
+ */
+#define MS_CONVERGE_TIME_SECS 5
 
 /* MS_HELLO_TIME_SECS
  * The length of time the sender will wait for the NBD hello message
@@ -38,12 +50,16 @@ enum mirror_state;
  * request, this is the time between the end of the NBD request and the
  * start of the NBD reply.  For a write request, this is the time
  * between the end of the written data and the start of the NBD reply.
+ * Can be overridden by the environment variable:
+ * FLEXNBD_MS_REQUEST_LIMIT_SECS
  */
-#define MS_REQUEST_LIMIT_SECS 4
 
+#define MS_REQUEST_LIMIT_SECS 60
+#define MS_REQUEST_LIMIT_SECS_F 60.0
 
 enum mirror_finish_action {
 	ACTION_EXIT,
+	ACTION_UNLINK,
 	ACTION_NOTHING
 };
 
@@ -51,6 +67,7 @@ enum mirror_state {
 	MS_UNKNOWN,
 	MS_INIT,
 	MS_GO,
+	MS_ABANDONED,
 	MS_DONE,
 	MS_FAIL_CONNECT,
 	MS_FAIL_REJECTED,
@@ -60,17 +77,25 @@ enum mirror_state {
 
 struct mirror {
 	pthread_t            thread;
-	/* set to 1, then join thread to make mirror terminate early */
-	int                  signal_abandon;
+
+	/* Signal to this then join the thread if you want to abandon mirroring */
+	struct self_pipe *   abandon_signal;
+
 	union mysockaddr *   connect_to;
 	union mysockaddr *   connect_from;
 	int                  client;
 	const char *         filename;
-	off64_t              max_bytes_per_second;
+
+	/* Limiter, used to restrict migration speed Only dirty bytes (those going
+	 * over the network) are considered */
+	uint64_t              max_bytes_per_second;
+
 	enum mirror_finish_action action_at_finish;
-	
+
 	char                 *mapped;
-	struct bitset_mapping *dirty_map;
+
+	/* We need to send every byte at least once; we do so by  */
+	uint64_t offset;
 
 	enum mirror_state    commit_state;
 
@@ -78,6 +103,13 @@ struct mirror {
 	 * and checking the remote size, whether successful or not.
 	 */
 	struct mbox *        commit_signal;
+
+	/* The time (from monotonic_time_ms()) the migration was started. Can be
+	 * used to calculate bps, etc. */
+	uint64_t migration_started;
+
+	/* Running count of all bytes we've transferred */
+	uint64_t all_dirty;
 };
 
 
@@ -99,9 +131,11 @@ struct mirror_super * mirror_super_create(
 		const char * filename,
 		union mysockaddr * connect_to,
 		union mysockaddr * connect_from,
-		int max_Bps,
-		int action_at_finish,
+		uint64_t max_Bps,
+		enum mirror_finish_action action_at_finish,
 		struct mbox * state_mbox
 		);
 void * mirror_super_runner( void * serve_uncast );
+
 #endif
+

src/server/mode.c

@@ -15,10 +15,11 @@ static struct option serve_options[] = {
 	GETOPT_SOCK,
 	GETOPT_DENY,
 	GETOPT_QUIET,
+	GETOPT_KILLSWITCH,
 	GETOPT_VERBOSE,
 	{0}
 };
-static char serve_short_options[] = "hl:p:f:s:d" SOPT_QUIET SOPT_VERBOSE;
+static char serve_short_options[] = "hl:p:f:s:dk" SOPT_QUIET SOPT_VERBOSE;
 static char serve_help_text[] =
 	"Usage: flexnbd " CMD_SERVE " <options> [<acl address>*]\n\n"
 	"Serve FILE from ADDR:PORT, with an optional control socket at SOCK.\n\n"
@@ -27,6 +28,7 @@ static char serve_help_text[] =
 	"\t--" OPT_PORT ",-p <PORT>\tThe port to serve on.\n"
 	"\t--" OPT_FILE ",-f <FILE>\tThe file to serve.\n"
 	"\t--" OPT_DENY ",-d\tDeny connections by default unless in ACL.\n"
+	"\t--" OPT_KILLSWITCH",-k  \tKill the server if a request takes 120 seconds.\n"
 	SOCK_LINE
 	VERBOSE_LINE
 	QUIET_LINE;
@@ -35,9 +37,7 @@ static char serve_help_text[] =
 static struct option listen_options[] = {
 	GETOPT_HELP,
 	GETOPT_ADDR,
-	GETOPT_REBIND_ADDR,
 	GETOPT_PORT,
-	GETOPT_REBIND_PORT,
 	GETOPT_FILE,
 	GETOPT_SOCK,
 	GETOPT_DENY,
@@ -45,24 +45,19 @@ static struct option listen_options[] = {
 	GETOPT_VERBOSE,
 	{0}
 };
-static char listen_short_options[] = "hl:L:p:P:f:s:d" SOPT_QUIET SOPT_VERBOSE;
+static char listen_short_options[] = "hl:p:f:s:d" SOPT_QUIET SOPT_VERBOSE;
 static char listen_help_text[] =
 	"Usage: flexnbd " CMD_LISTEN " <options> [<acl_address>*]\n\n"
-	"Listen for an incoming migration on ADDR:PORT, "
-	"then switch to REBIND_ADDR:REBIND_PORT on completion "
-	"to serve FILE.\n\n"
+	"Listen for an incoming migration on ADDR:PORT."
 	HELP_LINE
 	"\t--" OPT_ADDR ",-l <ADDR>\tThe address to listen on.\n"
-	"\t--" OPT_REBIND_ADDR ",-L <REBIND_ADDR>\tThe address to switch to, if given.\n"
 	"\t--" OPT_PORT ",-p <PORT>\tThe port to listen on.\n"
-	"\t--" OPT_REBIND_PORT ",-P <REBIND_PORT>\tThe port to switch to, if given..\n"
 	"\t--" OPT_FILE ",-f <FILE>\tThe file to serve.\n"
 	"\t--" OPT_DENY ",-d\tDeny connections by default unless in ACL.\n"
 	SOCK_LINE
 	VERBOSE_LINE
 	QUIET_LINE;
 
-
 static struct option read_options[] = {
 	GETOPT_HELP,
 	GETOPT_ADDR,
@@ -118,17 +113,36 @@ static char acl_help_text[] =
 	VERBOSE_LINE
 	QUIET_LINE;
 
+static struct option mirror_speed_options[] = {
+	GETOPT_HELP,
+	GETOPT_SOCK,
+	GETOPT_MAX_SPEED,
+	GETOPT_QUIET,
+	GETOPT_VERBOSE,
+	{0}
+};
+static char mirror_speed_short_options[] = "hs:m:" SOPT_QUIET SOPT_VERBOSE;
+static char mirror_speed_help_text[] =
+	"Usage: flexnbd " CMD_MIRROR_SPEED " <options>\n\n"
+	"Set the maximum speed of a migration from a mirring server listening on SOCK.\n\n"
+	HELP_LINE
+	SOCK_LINE
+	MAX_SPEED_LINE
+	VERBOSE_LINE
+	QUIET_LINE;
+
 static struct option mirror_options[] = {
 	GETOPT_HELP,
 	GETOPT_SOCK,
 	GETOPT_ADDR,
 	GETOPT_PORT,
+	GETOPT_UNLINK,
 	GETOPT_BIND,
 	GETOPT_QUIET,
 	GETOPT_VERBOSE,
 	{0}
 };
-static char mirror_short_options[] = "hs:l:p:b:" SOPT_QUIET SOPT_VERBOSE;
+static char mirror_short_options[] = "hs:l:p:ub:" SOPT_QUIET SOPT_VERBOSE;
 static char mirror_help_text[] =
 	"Usage: flexnbd " CMD_MIRROR " <options>\n\n"
 	"Start mirroring from the server with control socket SOCK to one at ADDR:PORT.\n\n"
@@ -136,10 +150,27 @@ static char mirror_help_text[] =
 	"\t--" OPT_ADDR ",-l <ADDR>\tThe address to mirror to.\n"
 	"\t--" OPT_PORT ",-p <PORT>\tThe port to mirror to.\n"
 	SOCK_LINE
+	"\t--" OPT_UNLINK ",-u\tUnlink the local file when done.\n"
 	BIND_LINE
 	VERBOSE_LINE
 	QUIET_LINE;
 
+static struct option break_options[] = {
+	GETOPT_HELP,
+	GETOPT_SOCK,
+	GETOPT_QUIET,
+	GETOPT_VERBOSE,
+	{0}
+};
+static char break_short_options[] = "hs:" SOPT_QUIET SOPT_VERBOSE;
+static char break_help_text[] =
+	"Usage: flexnbd " CMD_BREAK " <options>\n\n"
+	"Stop mirroring from the server with control socket SOCK.\n\n"
+	HELP_LINE
+	SOCK_LINE
+	VERBOSE_LINE
+	QUIET_LINE;
+
 
 static struct option status_options[] = {
 	GETOPT_HELP,
@@ -161,10 +192,13 @@ char help_help_text_arr[] =
 	"Usage: flexnbd <cmd> [cmd options]\n\n"
 	"Commands:\n"
 	"\tflexnbd serve\n"
+	"\tflexnbd listen\n"
 	"\tflexnbd read\n"
 	"\tflexnbd write\n"
 	"\tflexnbd acl\n"
 	"\tflexnbd mirror\n"
+	"\tflexnbd mirror-speed\n"
+	"\tflexnbd break\n"
 	"\tflexnbd status\n"
 	"\tflexnbd help\n\n"
 	"See flexnbd help <cmd> for further info\n";
@@ -175,19 +209,17 @@ char * help_help_text = help_help_text_arr;
 
 
 
-int do_serve(struct server* params);
 void do_read(struct mode_readwrite_params* params);
 void do_write(struct mode_readwrite_params* params);
 void do_remote_command(char* command, char* mode, int argc, char** argv);
 
 
-void read_serve_param( int c, char **ip_addr, char **ip_port, char **file, char **sock, int *default_deny )
+void read_serve_param( int c, char **ip_addr, char **ip_port, char **file, char **sock, int *default_deny, int *use_killswitch )
 {
 	switch(c){
 		case 'h':
 			fprintf(stdout, "%s\n", serve_help_text );
 			exit( 0 );
-			break;
 		case 'l':
 			*ip_addr = optarg;
 			break;
@@ -204,11 +236,14 @@ void read_serve_param( int c, char **ip_addr, char **ip_port, char **file, char
 			*default_deny = 1;
 			break;
 		case 'q':
-			log_level = 4;
+			log_level = QUIET_LOG_LEVEL;
 			break;
 		case 'v':
 			log_level = VERBOSE_LOG_LEVEL;
 			break;
+		case 'k':
+			*use_killswitch = 1;
+			break;
 		default:
 			exit_err( serve_help_text );
 			break;
@@ -216,32 +251,23 @@ void read_serve_param( int c, char **ip_addr, char **ip_port, char **file, char
 }
 
 
-void read_listen_param( int c, 
-		char **ip_addr, 
-		char **rebind_ip_addr, 
-		char **ip_port, 
-		char **rebind_ip_port, 
-		char **file, 
-		char **sock, 
+void read_listen_param( int c,
+		char **ip_addr,
+		char **ip_port,
+		char **file,
+		char **sock,
 		int *default_deny )
 {
 	switch(c){
 		case 'h':
 			fprintf(stdout, "%s\n", listen_help_text );
 			exit(0);
-			break;
 		case 'l':
 			*ip_addr = optarg;
 			break;
-		case 'L':
-			*rebind_ip_addr = optarg;
-			break;
 		case 'p':
 			*ip_port = optarg;
 			break;
-		case 'P':
-			*rebind_ip_port = optarg;
-			break;
 		case 'f':
 			*file = optarg;
 			break;
@@ -252,7 +278,7 @@ void read_listen_param( int c,
 			*default_deny = 1;
 			break;
 		case 'q':
-			log_level = 4;
+			log_level = QUIET_LOG_LEVEL;
 			break;
 		case 'v':
 			log_level = VERBOSE_LOG_LEVEL;
@@ -263,13 +289,12 @@ void read_listen_param( int c,
 	}
 }
 
-void read_readwrite_param( int c, char **ip_addr, char **ip_port, char **bind_addr, char **from, char **size)
+void read_readwrite_param( int c, char **ip_addr, char **ip_port, char **bind_addr, char **from, char **size, char *err_text )
 {
 	switch(c){
 		case 'h':
-			fprintf(stdout, "%s\n", read_help_text );
+			fprintf(stdout, "%s\n", err_text );
 			exit( 0 );
-			break;
 		case 'l':
 			*ip_addr = optarg;
 			break;
@@ -286,13 +311,13 @@ void read_readwrite_param( int c, char **ip_addr, char **ip_port, char **bind_ad
 			*bind_addr = optarg;
 			break;
 		case 'q':
-			log_level = 4;
+			log_level = QUIET_LOG_LEVEL;
 			break;
 		case 'v':
 			log_level = VERBOSE_LOG_LEVEL;
 			break;
 		default:
-			exit_err( read_help_text );
+			exit_err( err_text );
 			break;
 	}
 }
@@ -303,12 +328,11 @@ void read_sock_param( int c, char **sock, char *help_text )
 		case 'h':
 			fprintf( stdout, "%s\n", help_text );
 			exit( 0 );
-			break;
 		case 's':
 			*sock = optarg;
 			break;
 		case 'q':
-			log_level = 4;
+			log_level = QUIET_LOG_LEVEL;
 			break;
 		case 'v':
 			log_level = VERBOSE_LOG_LEVEL;
@@ -324,13 +348,47 @@ void read_acl_param( int c, char **sock )
 	read_sock_param( c, sock, acl_help_text );
 }
 
-void read_mirror_param( int c, char **sock, char **ip_addr, char **ip_port, char **bind_addr )
+void read_mirror_speed_param(
+		int c,
+		char **sock,
+		char **max_speed
+)
+{
+	switch( c ) {
+		case 'h':
+			fprintf( stdout, "%s\n", mirror_speed_help_text );
+			exit( 0 );
+		case 's':
+			*sock = optarg;
+			break;
+		case 'm':
+			*max_speed = optarg;
+			break;
+		case 'q':
+			log_level = QUIET_LOG_LEVEL;
+			break;
+		case 'v':
+			log_level = VERBOSE_LOG_LEVEL;
+			break;
+		default:
+			exit_err( mirror_speed_help_text );
+			break;
+
+	}
+}
+
+void read_mirror_param(
+		int c,
+		char **sock,
+		char **ip_addr,
+		char **ip_port,
+		int  *unlink,
+		char **bind_addr )
 {
 	switch( c ){
 		case 'h':
 			fprintf( stdout, "%s\n", mirror_help_text );
 			exit( 0 );
-			break;
 		case 's':
 			*sock = optarg;
 			break;
@@ -340,11 +398,14 @@ void read_mirror_param( int c, char **sock, char **ip_addr, char **ip_port, char
 		case 'p':
 			*ip_port = optarg;
 			break;
+		case 'u':
+			*unlink = 1;
+			break;
 		case 'b':
 			*bind_addr = optarg;
 			break;
 		case 'q':
-			log_level = 4;
+			log_level = QUIET_LOG_LEVEL;
 			break;
 		case 'v':
 			log_level = VERBOSE_LOG_LEVEL;
@@ -355,6 +416,28 @@ void read_mirror_param( int c, char **sock, char **ip_addr, char **ip_port, char
 	}
 }
 
+void read_break_param( int c, char **sock )
+{
+	switch( c ) {
+		case 'h':
+			fprintf( stdout, "%s\n", break_help_text );
+			exit( 0 );
+		case 's':
+			*sock = optarg;
+			break;
+		case 'q':
+			log_level = QUIET_LOG_LEVEL;
+			break;
+		case 'v':
+			log_level = VERBOSE_LOG_LEVEL;
+			break;
+		default:
+			exit_err( break_help_text );
+			break;
+	}
+}
+
+
 void read_status_param( int c, char **sock )
 {
 	read_sock_param( c, sock, status_help_text );
@@ -368,15 +451,18 @@ int mode_serve( int argc, char *argv[] )
 	char *file    = NULL;
 	char *sock    = NULL;
 	int default_deny = 0; // not on by default
+	int use_killswitch = 0;
 	int err = 0;
 
+	int success;
+
 	struct flexnbd * flexnbd;
 
 	while (1) {
 		c = getopt_long(argc, argv, serve_short_options, serve_options, NULL);
 		if ( c == -1 ) { break; }
 
-		read_serve_param( c, &ip_addr, &ip_port, &file, &sock, &default_deny );
+		read_serve_param( c, &ip_addr, &ip_port, &file, &sock, &default_deny, &use_killswitch );
 	}
 
 	if ( NULL == ip_addr || NULL == ip_port ) {
@@ -389,11 +475,12 @@ int mode_serve( int argc, char *argv[] )
 	}
 	if ( err ) { exit_err( serve_help_text ); }
 
-	flexnbd = flexnbd_create_serving( ip_addr, ip_port, file, sock, default_deny, argc - optind, argv + optind, MAX_NBD_CLIENTS );
-	flexnbd_serve( flexnbd );
+	flexnbd = flexnbd_create_serving( ip_addr, ip_port, file, sock, default_deny, argc - optind, argv + optind, MAX_NBD_CLIENTS, use_killswitch );
+	info( "Serving file %s", file );
+	success = flexnbd_serve( flexnbd );
 	flexnbd_destroy( flexnbd );
 
-	return 0;
+	return success ? 0 : 1;
 }
 
 
@@ -401,9 +488,7 @@ int mode_listen( int argc, char *argv[] )
 {
 	int c;
 	char *ip_addr = NULL;
-	char *rebind_ip_addr = NULL;
 	char *ip_port = NULL;
-	char *rebind_ip_port = NULL;
 	char *file    = NULL;
 	char *sock    = NULL;
 	int default_deny = 0; // not on by default
@@ -417,7 +502,7 @@ int mode_listen( int argc, char *argv[] )
 		c = getopt_long(argc, argv, listen_short_options, listen_options, NULL);
 		if ( c == -1 ) { break; }
 
-		read_listen_param( c, &ip_addr, &rebind_ip_addr, &ip_port, &rebind_ip_port, 
+		read_listen_param( c, &ip_addr, &ip_port,
 				&file, &sock, &default_deny );
 	}
 
@@ -431,17 +516,14 @@ int mode_listen( int argc, char *argv[] )
 	}
 	if ( err ) { exit_err( listen_help_text ); }
 
-	flexnbd = flexnbd_create_listening( 
-		ip_addr, 
-		rebind_ip_addr, 
-		ip_port, 
-		rebind_ip_port, 
+	flexnbd = flexnbd_create_listening(
+		ip_addr,
+		ip_port,
 		file,
 		sock,
-		default_deny, 
-		argc - optind, 
-		argv + optind, 
-		MAX_NBD_CLIENTS );
+		default_deny,
+		argc - optind,
+		argv + optind);
 	success = flexnbd_serve( flexnbd );
 	flexnbd_destroy( flexnbd );
 
@@ -484,14 +566,17 @@ void params_readwrite(
 		s_ip_address
 	);
 
-	if (s_bind_address != NULL && 
+	if (s_bind_address != NULL &&
 			parse_ip_to_sockaddr(&out->connect_from.generic, s_bind_address) == 0) {
 		fatal("Couldn't parse bind address '%s'", s_bind_address);
 	}
 
 	parse_port( s_port, &out->connect_to.v4 );
 
-	out->from  = atol(s_from);
+	long signed_from = atol(s_from);
+	FATAL_IF_NEGATIVE( signed_from,
+			"Can't read from a negative offset %d.", signed_from);
+	out->from  = signed_from;
 
 	if (write_not_read) {
 		if (s_length_or_filename[0]-48 < 10) {
@@ -503,9 +588,10 @@ void params_readwrite(
 			  s_length_or_filename, O_RDONLY);
 			FATAL_IF_NEGATIVE(out->data_fd,
 			  "Couldn't open %s", s_length_or_filename);
-			out->len = lseek64(out->data_fd, 0, SEEK_END);
-			FATAL_IF_NEGATIVE(out->len,
+			off64_t signed_len = lseek64(out->data_fd, 0, SEEK_END);
+			FATAL_IF_NEGATIVE(signed_len,
 			  "Couldn't find length of %s", s_length_or_filename);
+			out->len = signed_len;
 			FATAL_IF_NEGATIVE(
 				lseek64(out->data_fd, 0, SEEK_SET),
 				"Couldn't rewind %s", s_length_or_filename
@@ -536,7 +622,7 @@ int mode_read( int argc, char *argv[] )
 
 		if ( c == -1 ) { break; }
 
-		read_readwrite_param( c, &ip_addr, &ip_port, &bind_addr, &from, &size );
+		read_readwrite_param( c, &ip_addr, &ip_port, &bind_addr, &from, &size, read_help_text );
 	}
 
 	if ( NULL == ip_addr || NULL == ip_port ) {
@@ -571,7 +657,7 @@ int mode_write( int argc, char *argv[] )
 		c = getopt_long(argc, argv, write_short_options, write_options, NULL);
 		if ( c == -1 ) { break; }
 
-		read_readwrite_param( c, &ip_addr, &ip_port, &bind_addr, &from, &size );
+		read_readwrite_param( c, &ip_addr, &ip_port, &bind_addr, &from, &size, write_help_text );
 	}
 
 	if ( NULL == ip_addr || NULL == ip_port ) {
@@ -615,17 +701,52 @@ int mode_acl( int argc, char *argv[] )
 }
 
 
+int mode_mirror_speed( int argc, char *argv[] )
+{
+	int c;
+	char *sock = NULL;
+	char *speed = NULL;
+
+	while( 1 ) {
+		c = getopt_long( argc, argv, mirror_speed_short_options, mirror_speed_options, NULL );
+		if ( -1 == c ) { break; }
+		read_mirror_speed_param( c, &sock, &speed );
+	}
+
+	if ( NULL == sock ) {
+		fprintf( stderr, "--sock is required.\n" );
+		exit_err( mirror_speed_help_text );
+	}
+
+	if ( NULL == speed ) {
+		fprintf( stderr, "--max-speed is required.\n");
+		exit_err( mirror_speed_help_text );
+	}
+
+	do_remote_command( "mirror_max_bps", sock, 1, &speed );
+	return 0;
+}
+
+
 int mode_mirror( int argc, char *argv[] )
 {
 	int c;
 	char *sock = NULL;
 	char *remote_argv[4] = {0};
 	int err = 0;
+	int unlink = 0;
+
+	remote_argv[2] = "exit";
 
 	while (1) {
 		c = getopt_long( argc, argv, mirror_short_options, mirror_options, NULL);
 		if ( -1 == c ) { break; }
-		read_mirror_param( c, &sock, &remote_argv[0], &remote_argv[1], &remote_argv[2] );
+		read_mirror_param( c,
+				&sock,
+				&remote_argv[0],
+				&remote_argv[1],
+				&unlink,
+				&remote_argv[3] );
 	}
 
 	if ( NULL == sock ){
@@ -637,18 +758,40 @@ int mode_mirror( int argc, char *argv[] )
 		err = 1;
 	}
 	if ( err ) { exit_err( mirror_help_text ); }
-	
-	if (remote_argv[2] == NULL) {
-		do_remote_command( "mirror", sock, 2, remote_argv );
+	if ( unlink ) { remote_argv[2] = "unlink"; }
+
+	if (remote_argv[3] == NULL) {
+		do_remote_command( "mirror", sock, 3, remote_argv );
 	}
 	else {
-		do_remote_command( "mirror", sock, 3, remote_argv );
+		do_remote_command( "mirror", sock, 4, remote_argv );
 	}
 
 	return 0;
 }
 
 
+int mode_break( int argc, char *argv[] )
+{
+	int c;
+	char *sock = NULL;
+
+	while (1) {
+		c = getopt_long( argc, argv, break_short_options, break_options, NULL );
+		if ( -1 == c ) { break; }
+		read_break_param( c, &sock );
+	}
+
+	if ( NULL == sock ){
+		fprintf( stderr, "--sock is required.\n" );
+		exit_err( break_help_text );
+	}
+
+	do_remote_command( "break", sock, argc - optind, argv + optind );
+
+	return 0;
+}
+
 int mode_status( int argc, char *argv[] )
 {
 	int c;
@@ -662,7 +805,7 @@ int mode_status( int argc, char *argv[] )
 
 	if ( NULL == sock ){
 		fprintf( stderr, "--sock is required.\n" );
-		exit_err( acl_help_text );
+		exit_err( status_help_text );
 	}
 
 	do_remote_command( "status", sock, argc - optind, argv + optind );
@@ -670,7 +813,6 @@ int mode_status( int argc, char *argv[] )
 	return 0;
 }
 
-
 int mode_help( int argc, char *argv[] )
 {
 	char *cmd;
@@ -718,10 +860,15 @@ void mode(char* mode, int argc, char **argv)
 	}
 	else if ( IS_CMD( CMD_ACL, mode ) ) {
 		mode_acl( argc, argv );
+	} else if ( IS_CMD ( CMD_MIRROR_SPEED, mode ) ) {
+		mode_mirror_speed( argc, argv );
 	}
 	else if ( IS_CMD( CMD_MIRROR, mode ) ) {
 		mode_mirror( argc, argv );
 	}
+       	else if ( IS_CMD( CMD_BREAK, mode ) ) {
+		mode_break( argc, argv );
+	}
        	else if ( IS_CMD( CMD_STATUS, mode ) ) {
 		mode_status( argc, argv );
 	}
@@ -735,4 +882,3 @@ void mode(char* mode, int argc, char **argv)
 	exit(0);
 }
 
-

src/server/serve.c

@@ -2,6 +2,7 @@
 #include "client.h"
 #include "nbdtypes.h"
 #include "ioutil.h"
+#include "sockutil.h"
 #include "util.h"
 #include "bitset.h"
 #include "control.h"
@@ -20,22 +21,6 @@
 #include <sys/socket.h>
 #include <netinet/tcp.h>
 
-static inline void* sockaddr_address_data(struct sockaddr* sockaddr)
-{
-	NULLCHECK( sockaddr );
-
-	struct sockaddr_in*  in  = (struct sockaddr_in*) sockaddr;
-	struct sockaddr_in6* in6 = (struct sockaddr_in6*) sockaddr;
-	
-	if (sockaddr->sa_family == AF_INET) {
-		return &in->sin_addr;
-	}
-	if (sockaddr->sa_family == AF_INET6) {
-		return &in6->sin6_addr;
-	}
-	return NULL;
-}
-
 struct server * server_create (
 	struct flexnbd * flexnbd,
 	char* s_ip_address,
@@ -45,16 +30,20 @@ struct server * server_create (
 	int acl_entries,
 	char** s_acl_entries,
 	int max_nbd_clients,
-	int has_control)
+	int use_killswitch,
+	int success)
 {
 	NULLCHECK( flexnbd );
 	struct server * out;
 	out = xmalloc( sizeof( struct server ) );
 	out->flexnbd = flexnbd;
-	out->has_control = has_control;
+	out->success = success;
 	out->max_nbd_clients = max_nbd_clients;
-	out->nbd_client = xmalloc( max_nbd_clients * sizeof( struct client_tbl_entry ) );
+	out->use_killswitch = use_killswitch;
 
+	server_allow_new_clients( out );
+
+	out->nbd_client = xmalloc( max_nbd_clients * sizeof( struct client_tbl_entry ) );
 	out->tcp_backlog = 10; /* does this need to be settable? */
 
 	FATAL_IF_NULL(s_ip_address, "No IP address supplied");
@@ -64,7 +53,7 @@ struct server * server_create (
 	FATAL_IF_ZERO(
 		parse_ip_to_sockaddr(&out->bind_to.generic, s_ip_address),
 		"Couldn't parse server address '%s' (use 0 if "
-		"you want to bind to all IPs)", 
+		"you want to bind to all IPs)",
 		s_ip_address
 	);
 
@@ -77,12 +66,11 @@ struct server * server_create (
 	parse_port( s_port, &out->bind_to.v4 );
 
 	out->filename = s_file;
-	out->filename_incomplete = xmalloc(strlen(s_file)+11+1);
-	strcpy(out->filename_incomplete, s_file);
-	strcpy(out->filename_incomplete + strlen(s_file), ".INCOMPLETE");
 
-	out->l_io = flexthread_mutex_create();
-	out->l_acl= flexthread_mutex_create();
+	out->l_acl = flexthread_mutex_create();
+	out->l_start_mirror = flexthread_mutex_create();
+
+	out->mirror_can_start = 1;
 
 	out->close_signal = self_pipe_create();
 	out->acl_updated_signal = self_pipe_create();
@@ -90,6 +78,8 @@ struct server * server_create (
 	NULLCHECK( out->close_signal );
 	NULLCHECK( out->acl_updated_signal );
 
+	log_context = s_file;
+
 	return out;
 }
 
@@ -100,28 +90,29 @@ void server_destroy( struct server * serve )
 	self_pipe_destroy( serve->close_signal );
 	serve->close_signal = NULL;
 
+	flexthread_mutex_destroy( serve->l_start_mirror );
 	flexthread_mutex_destroy( serve->l_acl );
-	flexthread_mutex_destroy( serve->l_io );
 
-	if ( serve->acl ) { 
+	if ( serve->acl ) {
 		acl_destroy( serve->acl );
 		serve->acl = NULL;
 	}
 
-	free( serve->filename_incomplete );
-
 	free( serve->nbd_client );
 	free( serve );
 }
 
 
-void server_dirty(struct server *serve, off64_t from, int len)
+void server_unlink( struct server * serve )
 {
 	NULLCHECK( serve );
+	NULLCHECK( serve->filename );
+
+	FATAL_IF_NEGATIVE( unlink( serve->filename ),
+			"Failed to unlink %s: %s",
+			serve->filename,
+			strerror( errno ) );
 
-	if (serve->mirror) {
-		bitset_set_range(serve->mirror->dirty_map, from, len);
-	}
 }
 
 #define SERVER_LOCK( s, f, msg ) \
@@ -131,30 +122,6 @@ void server_dirty(struct server *serve, off64_t from, int len)
 	do { NULLCHECK( s ); \
 	 FATAL_IF( 0 != flexthread_mutex_unlock( s->f ), msg ); } while (0)
 
-void server_lock_io( struct server * serve)
-{
-	debug("IO locking");
-
-	SERVER_LOCK( serve, l_io, "Problem with I/O lock" );
-}
-
-void server_unlock_io( struct server* serve )
-{
-	debug("IO unlocking");
-
-	SERVER_UNLOCK( serve, l_io, "Problem with I/O unlock" );
-}
-
-
-/* This is only to be called from error handlers. */
-int server_io_locked( struct server * serve )
-{
-	NULLCHECK( serve );
-	return flexthread_mutex_held( serve->l_io );
-}
-
-
-
 void server_lock_acl( struct server *serve )
 {
 	debug("ACL locking");
@@ -164,6 +131,8 @@ void server_lock_acl( struct server *serve )
 
 void server_unlock_acl( struct server *serve )
 {
+	debug( "ACL unlocking" );
+
 	SERVER_UNLOCK( serve, l_acl, "Problem with ACL unlock" );
 }
 
@@ -175,6 +144,26 @@ int server_acl_locked( struct server * serve )
 }
 
 
+void server_lock_start_mirror( struct server *serve )
+{
+	debug("Mirror start locking");
+
+	SERVER_LOCK( serve, l_start_mirror, "Problem with start mirror lock" );
+}
+
+void server_unlock_start_mirror( struct server *serve )
+{
+	debug("Mirror start unlocking");
+
+	SERVER_UNLOCK( serve, l_start_mirror, "Problem with start mirror unlock" );
+}
+
+int server_start_mirror_locked( struct server * serve )
+{
+	NULLCHECK( serve );
+	return flexthread_mutex_held( serve->l_start_mirror );
+}
+
 /** Return the actual port the server bound to.  This is used because we
  * are allowed to pass "0" on the command-line.
  */
@@ -192,74 +181,15 @@ int server_port( struct server * server )
 }
 
 
-/* Try to bind to our serving socket, retrying until it works or gives a
- * fatal error. */
-void serve_bind( struct server * serve )
-{
-	int bind_result;
-
-	char s_address[64];
-	memset( s_address, 0, 64 );
-	strcpy( s_address, "???" );
-	inet_ntop( serve->bind_to.generic.sa_family,
-			sockaddr_address_data( &serve->bind_to.generic),
-			s_address, 64 );
-
-	do {
-		bind_result = bind(
-				serve->server_fd, 
-				&serve->bind_to.generic,
-				sizeof(serve->bind_to));
-
-		if ( 0 == bind_result ) {
-			info( "Bound to %s port %d", 
-					s_address, 
-					ntohs(serve->bind_to.v4.sin_port));
-			break;
-		}
-		else {
-
-			warn( "Couldn't bind to %s port %d: %s", 
-					s_address, 
-					ntohs(serve->bind_to.v4.sin_port),
-					strerror( errno ) );
-
-			switch (errno){
-				/* bind() can give us EACCES,
-				 * EADDRINUSE, EADDRNOTAVAIL, EBADF,
-				 * EINVAL or ENOTSOCK.
-				 *
-				 * Any of these other than EACCES, 
-				 * EADDRINUSE or EADDRNOTAVAIL signify
-				 * that there's a logic error somewhere.
-				 */
-				case EACCES:
-				case EADDRINUSE:
-				case EADDRNOTAVAIL:
-					debug("retrying");
-					sleep(1);
-					continue;
-				default:
-					fatal( "Giving up" );
-			}
-		}
-	} while ( 1 );
-}
-
-
-
 /** Prepares a listening socket for the NBD server, binding etc. */
 void serve_open_server_socket(struct server* params)
 {
 	NULLCHECK( params );
 
-	int optval=1;
-	
-	params->server_fd= socket(params->bind_to.generic.sa_family == AF_INET ? 
+	params->server_fd = socket(params->bind_to.generic.sa_family == AF_INET ?
 	  PF_INET : PF_INET6, SOCK_STREAM, 0);
-	
-	FATAL_IF_NEGATIVE(params->server_fd, 
-	  "Couldn't create server socket");
+
+	FATAL_IF_NEGATIVE( params->server_fd, "Couldn't create server socket" );
 
 	/* We need SO_REUSEADDR so that when we switch from listening to
 	 * serving we don't have to change address if we don't want to.
@@ -270,8 +200,7 @@ void serve_open_server_socket(struct server* params)
 	 * we barf.
 	 */
 	FATAL_IF_NEGATIVE(
-		setsockopt(params->server_fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)),
-		"Couldn't set SO_REUSEADDR"
+		sock_set_reuseaddr( params->server_fd, 1 ), "Couldn't set SO_REUSEADDR"
 	);
 
 	/* TCP_NODELAY makes everything not be slow.  If we can't set
@@ -279,15 +208,17 @@ void serve_open_server_socket(struct server* params)
 	 * understand.
 	 */
 	FATAL_IF_NEGATIVE(
-		setsockopt(params->server_fd, IPPROTO_TCP, TCP_NODELAY, &optval, sizeof(optval)),
-		"Couldn't set TCP_NODELAY"
+		sock_set_tcp_nodelay( params->server_fd, 1 ), "Couldn't set TCP_NODELAY"
 	);
 
 	/* If we can't bind, presumably that's because someone else is
 	 * squatting on our ip/port combo, or the ip isn't yet
 	 * configured. Ideally we want to retry this. */
-	serve_bind(params);
-	
+	FATAL_UNLESS_ZERO(
+		sock_try_bind( params->server_fd, &params->bind_to.generic ),
+		SHOW_ERRNO( "Failed to bind() socket" )
+	);
+
 	FATAL_IF_NEGATIVE(
 		listen(params->server_fd, params->tcp_backlog),
 		"Couldn't listen on server socket"
@@ -304,33 +235,29 @@ int tryjoin_client_thread( struct client_tbl_entry *entry, int (*joinfunc)(pthre
 
 	int was_closed = 0;
 	void * status=NULL;
-	int join_errno;
 
 	if (entry->thread != 0) {
-		char s_client_address[64];
+		char s_client_address[128];
 
-		memset(s_client_address, 0, 64);
-		strcpy(s_client_address, "???");
-		inet_ntop( entry->address.generic.sa_family, 
-				sockaddr_address_data(&entry->address.generic), 
-				s_client_address, 
-				64 );
+		sockaddr_address_string( &entry->address.generic, &s_client_address[0], 128 );
 
 		debug( "%s(%p,...)", joinfunc == pthread_join ? "joining" : "tryjoining", entry->thread );
-		join_errno = joinfunc(entry->thread, &status);
+		int join_errno = joinfunc(entry->thread, &status);
+
 		/* join_errno can legitimately be ESRCH if the thread is
 		 * already dead, but the client still needs tidying up. */
 		if (join_errno != 0 && !entry->client->stopped ) {
-			FATAL_UNLESS( join_errno == EBUSY,  
-					"Problem with joining thread %p: %s", 
+			debug( "join_errno was %s, stopped was %d", strerror( join_errno ), entry->client->stopped );
+			FATAL_UNLESS( join_errno == EBUSY,
+					"Problem with joining thread %p: %s",
 					entry->thread,
 					strerror(join_errno) );
 		}
-		else {
-			debug("nbd thread %016x exited (%s) with status %ld", 
-					entry->thread, 
-					s_client_address, 
-					(uint64_t)status);
+		else if ( join_errno == 0 ) {
+			debug("nbd thread %016x exited (%s) with status %ld",
+					entry->thread,
+					s_client_address,
+					(uintptr_t)status);
 			client_destroy( entry->client );
 			entry->client = NULL;
 			entry->thread = 0;
@@ -401,6 +328,20 @@ int cleanup_and_find_client_slot(struct server* params)
 	return slot;
 }
 
+int server_count_clients( struct server *params )
+{
+	NULLCHECK( params );
+	int i, count = 0;
+
+	for ( i = 0 ; i < params->max_nbd_clients ; i++ ) {
+		if ( params->nbd_client[i].thread != 0 ) {
+			count++;
+		}
+	}
+
+	return count;
+}
+
 
 /** Check whether the address client_address is allowed or not according
  * to the current acl.  If params->acl is NULL, the result will be 1,
@@ -425,8 +366,8 @@ int server_acl_accepts( struct server *params, union mysockaddr * client_address
 }
 
 
-int server_should_accept_client( 
-		struct server * params, 
+int server_should_accept_client(
+		struct server * params,
 		union mysockaddr * client_address,
 		char *s_client_address,
 		size_t s_client_address_len )
@@ -435,16 +376,18 @@ int server_should_accept_client(
 	NULLCHECK( client_address );
 	NULLCHECK( s_client_address );
 
-	if (inet_ntop(client_address->generic.sa_family,
-				sockaddr_address_data(&client_address->generic),
-				s_client_address, s_client_address_len ) == NULL) {
+	const char* result = sockaddr_address_string(
+		&client_address->generic, s_client_address, s_client_address_len
+	);
+
+	if ( NULL == result ) {
 		warn( "Rejecting client %s: Bad client_address", s_client_address );
 		return 0;
 	}
 
 	if ( !server_acl_accepts( params, client_address ) ) {
 		warn( "Rejecting client %s: Access control error", s_client_address );
-		debug( "We %s have an acl, and default_deny is %s", 
+		debug( "We %s have an acl, and default_deny is %s",
 				(params->acl ? "do" : "do not"),
 				(params->acl->default_deny ? "true" : "false") );
  		return 0;
@@ -455,8 +398,8 @@ int server_should_accept_client(
 
 
 
-int spawn_client_thread( 
-	struct client * client_params, 
+int spawn_client_thread(
+	struct client * client_params,
 	pthread_t *out_thread)
 {
 	int result = pthread_create(out_thread, NULL, client_serve, client_params);
@@ -470,8 +413,8 @@ int spawn_client_thread(
   * address doesn't match, or if there are too many clients already connected.
   */
 void accept_nbd_client(
-		struct server* params, 
-		int client_fd, 
+		struct server* params,
+		int client_fd,
 		union mysockaddr* client_address)
 {
 	NULLCHECK(params);
@@ -481,35 +424,44 @@ void accept_nbd_client(
 	int slot;
 	char s_client_address[64] = {0};
 
+	FATAL_IF_NEGATIVE( sock_set_keepalive_params( client_fd, CLIENT_KEEPALIVE_TIME, CLIENT_KEEPALIVE_INTVL, CLIENT_KEEPALIVE_PROBES),
+		"Error setting keepalive parameters on client socket fd %d", client_fd );
+
 
 	if ( !server_should_accept_client( params, client_address, s_client_address, 64 ) ) {
-		close( client_fd );
+		FATAL_IF_NEGATIVE( close( client_fd ),
+			"Error closing client socket fd %d", client_fd );
+		debug("Closed client socket fd %d", client_fd);
 		return;
 	}
 
-	slot = cleanup_and_find_client_slot(params); 
+	slot = cleanup_and_find_client_slot(params);
 	if (slot < 0) {
 		warn("too many clients to accept connection");
-		close(client_fd);
+		FATAL_IF_NEGATIVE( close( client_fd ),
+			"Error closing client socket fd %d", client_fd );
+		debug("Closed client socket fd %d", client_fd);
 		return;
 	}
-	
-	debug( "Client %s accepted.", s_client_address );
+
+	info( "Client %s accepted on fd %d.", s_client_address, client_fd );
 	client_params = client_create( params, client_fd );
 
 	params->nbd_client[slot].client = client_params;
-	memcpy(&params->nbd_client[slot].address, client_address, 
+	memcpy(&params->nbd_client[slot].address, client_address,
 	  sizeof(union mysockaddr));
-	
+
 	pthread_t * thread = &params->nbd_client[slot].thread;
 
 	if ( 0 != spawn_client_thread( client_params, thread ) ) {
 		debug( "Thread creation problem." );
 		client_destroy( client_params );
-		close(client_fd);
+		FATAL_IF_NEGATIVE( close(client_fd),
+			"Error closing client socket fd %d", client_fd );
+		debug("Closed client socket fd %d", client_fd);
 		return;
 	}
-	
+
 	debug("nbd thread %p started (%s)", params->nbd_client[slot].thread, s_client_address);
 }
 
@@ -526,7 +478,7 @@ void server_audit_clients( struct server * serve)
 	 * won't have been audited against the later acl.  This isn't a
 	 * problem though, because in order to update the acl
 	 * server_replace_acl must have been called, so the
-	 * server_accept ioop will see a second acl_updated signal as
+	 * server_accept loop will see a second acl_updated signal as
 	 * soon as it hits select, and a second audit will be run.
 	 */
 	for( i = 0; i < serve->max_nbd_clients; i++ ) {
@@ -548,10 +500,10 @@ int server_is_closed(struct server* serve)
 void server_close_clients( struct server *params )
 {
 	NULLCHECK(params);
-	
+
 	info("closing all clients");
 
-	int i, j;
+	int i; /* , j; */
 	struct client_tbl_entry *entry;
 
 	for( i = 0; i < params->max_nbd_clients; i++ ) {
@@ -559,12 +511,20 @@ void server_close_clients( struct server *params )
 
 		if ( entry->thread != 0 ) {
 			debug( "Stop signaling client %p", entry->client );
-			client_signal_stop( entry->client );	
+			client_signal_stop( entry->client );
 		}
 	}
-	for( j = 0; j < params->max_nbd_clients; j++ ) {
-		join_client_thread( &params->nbd_client[j] );
-	}
+	/* We don't join the clients here.  When we enter the final
+	 * mirror pass, we get the IO lock, then wait for the server_fd
+	 * to close before sending the data, to be sure that no new
+	 * clients can be accepted which might think they've written
+	 * to the disc.  However, an existing client thread can be
+	 * waiting for the IO lock already, so if we try to join it
+	 * here, we deadlock.
+	 *
+	 * The client threads will be joined in serve_cleanup.
+	 *
+	*/
 }
 
 
@@ -592,19 +552,63 @@ void server_replace_acl( struct server *serve, struct acl * new_acl )
 }
 
 
+void server_prevent_mirror_start( struct server *serve )
+{
+	NULLCHECK( serve );
+
+	serve->mirror_can_start = 0;
+}
+
+void server_allow_mirror_start( struct server *serve )
+{
+	NULLCHECK( serve );
+
+	serve->mirror_can_start = 1;
+}
+
+
+/* Only call this with the mirror start lock held */
+int server_mirror_can_start( struct server *serve )
+{
+	NULLCHECK( serve );
+
+	return serve->mirror_can_start;
+}
+
+
+/* Queries to see if we are currently mirroring.  If we are, we need
+ * to communicate that via the process exit status. because otherwise
+ * the supervisor will assume the migration completed.
+ */
+int serve_shutdown_is_graceful( struct server *params )
+{
+	int is_mirroring = 0;
+	server_lock_start_mirror( params );
+	{
+		if ( server_is_mirroring( params ) ) {
+			is_mirroring = 1;
+			warn( "Stop signal received while mirroring." );
+			server_prevent_mirror_start( params );
+		}
+	}
+	server_unlock_start_mirror( params );
+
+	return !is_mirroring;
+}
+
 
 /** Accept either an NBD or control socket connection, dispatch appropriately */
 int server_accept( struct server * params )
 {
 	NULLCHECK( params );
 	debug("accept loop starting");
-	int              client_fd;
 	union mysockaddr client_address;
 	fd_set           fds;
 	socklen_t        socklen=sizeof(client_address);
 	/* We select on this fd to receive OS signals (only a few of
 	 * which we're interested in, see flexnbd.c */
 	int              signal_fd = flexnbd_signal_fd( params->flexnbd );
+	int              should_continue = 1;
 
 	FD_ZERO(&fds);
 	FD_SET(params->server_fd, &fds);
@@ -612,18 +616,22 @@ int server_accept( struct server * params )
 	self_pipe_fd_set( params->close_signal, &fds );
 	self_pipe_fd_set( params->acl_updated_signal, &fds );
 
-	FATAL_IF_NEGATIVE(select(FD_SETSIZE, &fds, 
-				NULL, NULL, NULL), "select() failed");
+	FATAL_IF_NEGATIVE(
+		sock_try_select(FD_SETSIZE, &fds, NULL, NULL, NULL),
+		SHOW_ERRNO( "select() failed" )
+	);
 
 	if ( self_pipe_fd_isset( params->close_signal, &fds ) ){
 		server_close_clients( params );
-		return 0;
+		should_continue = 0;
 	}
 
+
 	if ( 0 < signal_fd && FD_ISSET( signal_fd, &fds ) ){
 		debug( "Stop signal received." );
 		server_close_clients( params );
-		return 0;
+		params->success = params->success && serve_shutdown_is_graceful( params );
+		should_continue = 0;
 	}
 
 
@@ -633,42 +641,124 @@ int server_accept( struct server * params )
 	}
 
 	if ( FD_ISSET( params->server_fd, &fds ) ){
-		client_fd = accept( params->server_fd, &client_address.generic, &socklen );
-		debug("Accepted nbd client socket");
-		accept_nbd_client(params, client_fd, &client_address);
-	} 
+		int client_fd = accept( params->server_fd, &client_address.generic, &socklen );
 
-	return 1;
+		if ( params->allow_new_clients ) {
+			debug("Accepted nbd client socket fd %d", client_fd);
+			accept_nbd_client(params, client_fd, &client_address);
+		} else {
+			debug( "New NBD client socket %d not allowed", client_fd );
+			sock_try_close( client_fd );
+		}
+	}
+
+	return should_continue;
 }
 
 
-void serve_accept_loop(struct server* params) 
+void serve_accept_loop(struct server* params)
 {
 	NULLCHECK( params );
 	while( server_accept( params ) );
 }
 
+void* build_allocation_map_thread(void* serve_uncast)
+{
+	NULLCHECK( serve_uncast );
+
+	struct server* serve = (struct server*) serve_uncast;
+
+	NULLCHECK( serve->filename );
+	NULLCHECK( serve->allocation_map );
+
+	int fd = open( serve->filename, O_RDONLY );
+	FATAL_IF_NEGATIVE( fd, "Couldn't open %s", serve->filename );
+
+	if ( build_allocation_map( serve->allocation_map, fd ) ) {
+		serve->allocation_map_built = 1;
+	}
+	else {
+		/* We can operate without it, but we can't free it without a race.
+		 * All that happens if we leave it is that it gradually builds up an
+		 * *incomplete* record of writes. Nobody will use it, as
+		 * allocation_map_built == 0 for the lifetime of the process.
+		 *
+		 * The stream functionality can still be relied on. We don't need to
+		 * worry about mirroring waiting for the allocation map to finish,
+		 * because we already copy every byte at least once. If that changes in
+		 * the future, we'll need to wait for the allocation map to finish or
+		 * fail before we can complete the migration.
+		 */
+		serve->allocation_map_not_built = 1;
+		warn( "Didn't build allocation map for %s", serve->filename );
+	}
+
+	close( fd );
+	return NULL;
+}
+
 /** Initialisation function that sets up the initial allocation map, i.e. so
   * we know which blocks of the file are allocated.
   */
 void serve_init_allocation_map(struct server* params)
 {
 	NULLCHECK( params );
+	NULLCHECK( params->filename );
 
-	int fd = open(params->filename, O_RDONLY);
+	int fd = open( params->filename, O_RDONLY );
 	off64_t size;
 
-	FATAL_IF_NEGATIVE(fd, "Couldn't open %s", params->filename);
-	size = lseek64(fd, 0, SEEK_END);
+	FATAL_IF_NEGATIVE(fd, "Couldn't open %s", params->filename );
+	size = lseek64( fd, 0, SEEK_END );
 	params->size = size;
-	FATAL_IF_NEGATIVE(size, "Couldn't find size of %s", 
-			params->filename);
-	params->allocation_map = 
-		build_allocation_map(fd, size, block_allocation_resolution);
-	close(fd);
+	FATAL_IF_NEGATIVE( size, "Couldn't find size of %s",
+			   params->filename );
+
+	params->allocation_map =
+		bitset_alloc( params->size, block_allocation_resolution );
+
+	int ok = pthread_create( &params->allocation_map_builder_thread,
+				 NULL,
+				 build_allocation_map_thread,
+				 params );
+
+	FATAL_IF_NEGATIVE( ok, "Couldn't create thread" );
 }
 
 
+void server_forbid_new_clients( struct server * serve )
+{
+	serve->allow_new_clients = 0;
+	return;
+}
+
+void server_allow_new_clients( struct server * serve )
+{
+	serve->allow_new_clients = 1;
+	return;
+}
+
+void server_join_clients( struct server * serve ) {
+	int i;
+	void* status;
+
+	for (i=0; i < serve->max_nbd_clients; i++) {
+		pthread_t thread_id = serve->nbd_client[i].thread;
+
+		if (thread_id != 0) {
+			debug( "joining thread %p", thread_id );
+			int err = pthread_join( thread_id, &status );
+			if ( 0 == err ) {
+				serve->nbd_client[i].thread = 0;
+			} else {
+				warn( "Error %s (%i) joining thread %p", strerror( err ), err, thread_id );
+			}
+		}
+	}
+
+	return;
+}
+
 /* Tell the server to close all the things. */
 void serve_signal_close( struct server * serve )
 {
@@ -677,6 +767,7 @@ void serve_signal_close( struct server * serve )
 	self_pipe_signal( serve->close_signal );
 }
 
+
 /* Block until the server closes the server_fd.
  */
 void serve_wait_for_close( struct server * serve )
@@ -686,55 +777,73 @@ void serve_wait_for_close( struct server * serve )
 	}
 }
 
-/* We've just had an ENTRUST/DISCONNECT pair, so we need to shut down
+/* We've just had an DISCONNECT pair, so we need to shut down
  * and signal our listener that we can safely take over.
  */
 void server_control_arrived( struct server *serve )
 {
+	debug( "server_control_arrived" );
 	NULLCHECK( serve );
 
-	serve->has_control = 1;
-	serve_signal_close( serve );
+	if ( !serve->success ) {
+		serve->success = 1;
+		serve_signal_close( serve );
+	}
 }
 
 
+void flexnbd_stop_control( struct flexnbd * flexnbd );
+
 /** Closes sockets, frees memory and waits for all client threads to finish */
-void serve_cleanup(struct server* params, 
+void serve_cleanup(struct server* params,
 		int fatal __attribute__ ((unused)) )
 {
 	NULLCHECK( params );
-	
+	void* status;
+
 	info("cleaning up");
 
-	int i;
-	
 	if (params->server_fd){ close(params->server_fd); }
 
-	if (params->allocation_map) {
-		free(params->allocation_map);
-	}
-	
-	if (params->mirror_super) {
-		/* AWOOGA!  RACE! */
-		pthread_t mirror_t = params->mirror_super->thread;
-		params->mirror->signal_abandon = 1;
-		pthread_join( mirror_t, NULL );
-	}
-	
-	for (i=0; i < params->max_nbd_clients; i++) {
-		void* status;
-		pthread_t thread_id = params->nbd_client[i].thread;
-		
-		if (thread_id != 0) {
-			debug("joining thread %p", thread_id);
-			pthread_join(thread_id, &status);
+	/* need to stop background build if we're killed very early on */
+	pthread_cancel(params->allocation_map_builder_thread);
+	pthread_join(params->allocation_map_builder_thread, &status);
+
+	int need_mirror_lock;
+	need_mirror_lock = !server_start_mirror_locked( params );
+
+	if ( need_mirror_lock ) { server_lock_start_mirror( params ); }
+	{
+		if ( server_is_mirroring( params ) ) {
+			server_abandon_mirror( params );
 		}
+		server_prevent_mirror_start( params );
+	}
+	if ( need_mirror_lock ) { server_unlock_start_mirror( params ); }
+
+	server_join_clients( params );
+
+	if (params->allocation_map) {
+		bitset_free( params->allocation_map );
+	}
+
+	if ( server_start_mirror_locked( params ) ) {
+		server_unlock_start_mirror( params );
 	}
 
 	if ( server_acl_locked( params ) ) {
 		server_unlock_acl( params );
 	}
 
+	/* if( params->flexnbd ) { */
+	/* 	if ( params->flexnbd->control ) { */
+	/* 		flexnbd_stop_control( params->flexnbd ); */
+	/* 	} */
+	/* 	flexnbd_destroy( params->flexnbd ); */
+	/* } */
+
+	/* server_destroy( params ); */
+
 	debug( "Cleanup done");
 }
 
@@ -742,7 +851,83 @@ void serve_cleanup(struct server* params,
 int server_is_in_control( struct server *serve )
 {
 	NULLCHECK( serve );
-	return serve->has_control;
+	return serve->success;
+}
+
+int server_is_mirroring( struct server * serve )
+{
+	NULLCHECK( serve );
+	return !!serve->mirror_super;
+}
+
+uint64_t server_mirror_bytes_remaining( struct server * serve )
+{
+	if ( server_is_mirroring( serve ) ) {
+		uint64_t bytes_to_xfer =
+			bitset_stream_queued_bytes( serve->allocation_map, BITSET_STREAM_SET ) +
+			( serve->size - serve->mirror->offset );
+
+		return bytes_to_xfer;
+	}
+
+	return 0;
+}
+
+/* Given historic bps measurements and number of bytes left to transfer, give
+ * an estimate of how many seconds are remaining before the migration is
+ * complete, assuming no new bytes are written.
+ */
+
+uint64_t server_mirror_eta( struct server * serve )
+{
+	if ( server_is_mirroring( serve ) ) {
+		uint64_t bytes_to_xfer = server_mirror_bytes_remaining( serve );
+		return bytes_to_xfer / ( server_mirror_bps( serve ) + 1 );
+	}
+
+	return 0;
+}
+
+uint64_t server_mirror_bps( struct server * serve )
+{
+	if ( server_is_mirroring( serve ) ) {
+	 	uint64_t duration_ms =
+	 		monotonic_time_ms() - serve->mirror->migration_started;
+
+		return serve->mirror->all_dirty / ( ( duration_ms / 1000 ) + 1 );
+	}
+
+	return 0;
+}
+
+void mirror_super_destroy( struct mirror_super * super );
+
+/* This must only be called with the start_mirror lock held */
+void server_abandon_mirror( struct server * serve )
+{
+	NULLCHECK( serve );
+	if ( serve->mirror_super ) {
+		/* FIXME: AWOOGA!  RACE!
+		 * We can set abandon_signal after mirror_super has checked it, but
+		 * before the reset. However, mirror_reset doesn't clear abandon_signal
+		 * so it'll just terminate early on the next pass. */
+		ERROR_UNLESS(
+			self_pipe_signal( serve->mirror->abandon_signal ),
+			"Failed to signal abandon to mirror"
+		);
+
+		pthread_t tid = serve->mirror_super->thread;
+		pthread_join( tid, NULL );
+		debug( "Mirror thread %p pthread_join returned", tid );
+
+		server_allow_mirror_start( serve );
+		mirror_super_destroy( serve->mirror_super );
+
+		serve->mirror = NULL;
+		serve->mirror_super = NULL;
+
+		debug( "Mirror supervisor done." );
+	}
 }
 
 int server_default_deny( struct server * serve )
@@ -752,19 +937,23 @@ int server_default_deny( struct server * serve )
 }
 
 /** Full lifecycle of the server */
-int do_serve(struct server* params)
+int do_serve( struct server* params, struct self_pipe * open_signal )
 {
 	NULLCHECK( params );
 
-	int has_control;
-	
+	int success;
+
 	error_set_handler((cleanup_handler*) serve_cleanup, params);
 	serve_open_server_socket(params);
+
+	/* Only signal that we are open for business once the server
+	   socket is open */
+	if ( NULL != open_signal ) { self_pipe_signal( open_signal ); }
+
 	serve_init_allocation_map(params);
 	serve_accept_loop(params);
-	has_control = params->has_control;
+	success = params->success;
 	serve_cleanup(params, 0);
 
-	return has_control;
+	return success;
 }
-

src/server/serve.h

@@ -0,0 +1,170 @@
+#ifndef SERVE_H
+#define SERVE_H
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <signal.h> /* for sig_atomic_t */
+
+#include "flexnbd.h"
+#include "parse.h"
+#include "acl.h"
+
+
+static const int block_allocation_resolution = 4096;//128<<10;
+
+
+struct client_tbl_entry {
+	pthread_t thread;
+	union mysockaddr address;
+	struct client * client;
+};
+
+
+#define MAX_NBD_CLIENTS 16
+#define CLIENT_KEEPALIVE_TIME 30
+#define CLIENT_KEEPALIVE_INTVL 10
+#define CLIENT_KEEPALIVE_PROBES 3
+struct server {
+	/* The flexnbd wrapper this server is attached to */
+	struct flexnbd * flexnbd;
+
+	/** address/port to bind to */
+	union mysockaddr     bind_to;
+	/** (static) file name to serve */
+	char*                filename;
+	/** TCP backlog for listen() */
+	int                  tcp_backlog;
+	/** (static) file name of UNIX control socket (or NULL if none) */
+	char*                control_socket_name;
+	/** size of file */
+	uint64_t 	     size;
+
+	/** to interrupt accept loop and clients, write() to close_signal[1] */
+	struct self_pipe *   close_signal;
+
+	/** access control list */
+	struct acl *         acl;
+	/** acl_updated_signal will be signalled after the acl struct
+	 * has been replaced
+	 */
+	struct self_pipe *   acl_updated_signal;
+
+	/* Claimed around any updates to the ACL. */
+	struct flexthread_mutex *   l_acl;
+
+	/* Claimed around starting a mirror so that it doesn't race with
+	 * shutting down on a SIGTERM. */
+	struct flexthread_mutex *   l_start_mirror;
+
+	struct mirror* mirror;
+	struct mirror_super * mirror_super;
+	/* This is used to stop the mirror from starting after we
+	 * receive a SIGTERM */
+	int mirror_can_start;
+
+	int                  server_fd;
+	int                  control_fd;
+
+	/* the allocation_map keeps track of which blocks in the backing file
+	 * have been allocated, or part-allocated on disc, with unallocated
+	 * blocks presumed to contain zeroes (i.e. represented as sparse files
+	 * by the filesystem).  We can use this information when receiving
+	 * incoming writes, and avoid writing zeroes to unallocated sections
+	 * of the file which would needlessly increase disc usage.  This
+	 * bitmap will start at all-zeroes for an empty file, and tend towards
+	 * all-ones as the file is written to (i.e. we assume that allocated
+	 * blocks can never become unallocated again, as is the case with ext3
+	 * at least).
+	 */
+	struct bitset * allocation_map;
+	/* when starting up, this thread builds the allocation_map */
+	pthread_t               allocation_map_builder_thread;
+
+	/* when the thread has finished, it sets this to 1 */
+	volatile sig_atomic_t  allocation_map_built;
+	volatile sig_atomic_t  allocation_map_not_built;
+
+	int                  max_nbd_clients;
+	struct client_tbl_entry *nbd_client;
+
+	/** Should clients use the killswitch? */
+	int use_killswitch;
+
+	/** If this isn't set, newly accepted clients will be closed immediately */
+	int allow_new_clients;
+
+	/* Marker for whether this server has control over the data in
+	 * the file, or if we're waiting to receive it from an inbound
+	 * migration which hasn't yet finished.
+	 *
+	 * It's the value which controls the exit status of a serve or
+	 * listen process.
+	 */
+	int success;
+};
+
+struct server * server_create(
+		struct flexnbd * flexnbd,
+		char* s_ip_address,
+		char* s_port,
+		char* s_file,
+		int default_deny,
+		int acl_entries,
+		char** s_acl_entries,
+		int max_nbd_clients,
+		int use_killswitch,
+		int success );
+void server_destroy( struct server * );
+int server_is_closed(struct server* serve);
+void serve_signal_close( struct server *serve );
+void serve_wait_for_close( struct server * serve );
+void server_replace_acl( struct server *serve, struct acl * acl);
+void server_control_arrived( struct server *serve );
+int server_is_in_control( struct server *serve );
+int server_default_deny( struct server * serve );
+int server_acl_locked( struct server * serve );
+void server_lock_acl( struct server *serve );
+void server_unlock_acl( struct server *serve );
+void server_lock_start_mirror( struct server *serve );
+void server_unlock_start_mirror( struct server *serve );
+int server_is_mirroring( struct server * serve );
+
+uint64_t server_mirror_bytes_remaining( struct server * serve );
+uint64_t server_mirror_eta( struct server * serve );
+uint64_t server_mirror_bps( struct server * serve );
+
+void server_abandon_mirror( struct server * serve );
+void server_prevent_mirror_start( struct server *serve );
+void server_allow_mirror_start( struct server *serve );
+int server_mirror_can_start( struct server *serve );
+
+/* These three functions are used by mirror around the final pass, to close
+ * existing clients and prevent new ones from being around
+ */
+
+void server_forbid_new_clients( struct server *serve );
+void server_close_clients( struct server *serve );
+void server_join_clients( struct server *serve );
+void server_allow_new_clients( struct server *serve );
+
+/* Returns a count (ish) of the number of currently-running client threads */
+int server_count_clients( struct server *params );
+
+void server_unlink( struct server * serve );
+
+int do_serve( struct server *, struct self_pipe * );
+
+struct mode_readwrite_params {
+	union mysockaddr     connect_to;
+	union mysockaddr     connect_from;
+
+	uint64_t             from;
+	uint32_t             len;
+
+	int                  data_fd;
+	int                  client;
+};
+
+
+#endif
+

src/server/status.c

@@ -0,0 +1,80 @@
+#include "status.h"
+#include "serve.h"
+#include "util.h"
+
+struct status * status_create( struct server * serve )
+{
+	NULLCHECK( serve );
+	struct status * status;
+
+	status = xmalloc( sizeof( struct status ) );
+	status->pid = getpid();
+	status->size = serve->size;
+	status->has_control = serve->success;
+
+	status->clients_allowed = serve->allow_new_clients;
+	status->num_clients = server_count_clients( serve );
+
+	server_lock_start_mirror( serve );
+
+	status->is_mirroring = NULL != serve->mirror;
+	if ( status->is_mirroring ) {
+		status->migration_duration = monotonic_time_ms();
+
+		if ( ( serve->mirror->migration_started ) < status->migration_duration ) {
+			status->migration_duration -= serve->mirror->migration_started;
+		} else {
+			status->migration_duration = 0;
+		}
+		status->migration_duration /= 1000;
+		status->migration_speed = server_mirror_bps( serve );
+		status->migration_speed_limit = serve->mirror->max_bytes_per_second;
+
+		status->migration_seconds_left = server_mirror_eta( serve );
+		status->migration_bytes_left = server_mirror_bytes_remaining( serve );
+	}
+
+	server_unlock_start_mirror( serve );
+
+	return status;
+
+}
+
+#define BOOL_S(var) (var ? "true" : "false" )
+#define PRINT_BOOL( var ) \
+	do{dprintf( fd, #var "=%s ", BOOL_S( status->var ) );}while(0)
+#define PRINT_INT( var ) \
+	do{dprintf( fd, #var "=%d ", status->var );}while(0)
+#define PRINT_UINT64( var ) \
+	do{dprintf( fd, #var "=%"PRIu64" ", status->var );}while(0)
+
+int status_write( struct status * status, int fd )
+{
+	PRINT_INT( pid );
+	PRINT_UINT64( size );
+	PRINT_BOOL( is_mirroring );
+	PRINT_BOOL( clients_allowed );
+	PRINT_INT( num_clients );
+	PRINT_BOOL( has_control );
+
+	if ( status->is_mirroring ) {
+		PRINT_UINT64( migration_speed );
+		PRINT_UINT64( migration_duration );
+		PRINT_UINT64( migration_seconds_left );
+		PRINT_UINT64( migration_bytes_left );
+		if ( status->migration_speed_limit < UINT64_MAX ) {
+			PRINT_UINT64( migration_speed_limit );
+		};
+	}
+
+	dprintf(fd, "\n");
+	return 1;
+}
+
+
+void status_destroy( struct status * status )
+{
+	NULLCHECK( status );
+	free( status );
+}
+

src/server/status.h

@@ -17,6 +17,12 @@
  *
  * The following status fields are defined:
  *
+ * pid:
+ *      The current process ID.
+ *
+ * size:
+ *  The size of the backing file being served, in bytes.
+ *
  * has_control:
  * 	This will be false when the server is listening for an incoming
  * 	migration.  It will switch to true when the end-of-migration
@@ -24,21 +30,63 @@
  * 	If the server is started in "serve" mode, this will never be
  * 	false.
  *
+ * clients_allowed:
+ *   This will be false if the server is not currently allowing new
+ *   connections, for instance, if we're in the migration endgame.
+ *
+ * num_clients:
+ *   This tells us how many clients are currently running. If we're in the
+ *   migration endgame, it should be 0
+ *
  * is_migrating:
  * 	This will be false when the server is started in either "listen"
  * 	or "serve" mode.  It will become true when a server in "serve"
  * 	mode starts a migration, and will become false again when the
  * 	migration terminates, successfully or not.
- *	If the server is currently in "listen" mode, this will never b
+ *	If the server is currently in "listen" mode, this will never be
  *	true.
+ *
+ *
+ * If is_migrating is true, then a number of other attributes may appear,
+ * relating to the progress of the migration.
+ *
+ * migration_duration:
+ *   How long the migration has been running for, in ms.
+ *
+ * migration_speed:
+ *   Network transfer speed, in bytes/second. This only takes dirty bytes
+ *   into account.
+ *
+ * migration_speed_limit:
+ *   If set, the speed we're going to try to limit the migration to.
+ *
+ * migration_seconds_left:
+ *   Our current best estimate of how many seconds are left before the migration
+ *   migration is finished.
+ *
+ * migration_bytes_left:
+ *   The number of bytes remaining to migrate.
  */
 
 
 #include "serve.h"
 
+#include <sys/types.h>
+#include <unistd.h>
+
 struct status {
+	pid_t pid;
+	uint64_t size;
 	int has_control;
+	int clients_allowed;
+	int num_clients;
 	int is_mirroring;
+
+	uint64_t migration_duration;
+	uint64_t migration_speed;
+	uint64_t migration_speed_limit;
+	uint64_t migration_seconds_left;
+	uint64_t migration_bytes_left;
 };
 
 /** Create a status object for the given server. */
@@ -53,3 +101,4 @@ void status_destroy( struct status * );
 
 
 #endif
+

src/status.c

@@ -1,34 +0,0 @@
-#include "status.h"
-#include "serve.h"
-#include "util.h"
-
-struct status * status_create( struct server * serve )
-{
-	NULLCHECK( serve );
-	struct status * status;
-	
-	status = xmalloc( sizeof( struct status ) );
-	status->has_control = serve->has_control;
-	status->is_mirroring = NULL != serve->mirror;
-	return status;
-
-}
-
-#define BOOL_S(var) (var ? "true" : "false" )
-#define PRINT_FIELD( var ) \
-	do{dprintf( fd, #var "=%s ", BOOL_S( status->var ) );}while(0)
-
-int status_write( struct status * status, int fd )
-{
-	PRINT_FIELD( is_mirroring );
-	PRINT_FIELD( has_control );
-	dprintf(fd, "\n");
-	return 1;
-}
-
-
-void status_destroy( struct status * status )
-{
-	NULLCHECK( status );
-	free( status );
-}

tests/acceptance/custom.supp

@@ -0,0 +1,13 @@
+{
+   avoid_glibc_bug_do_lookup
+   Memcheck:Addr8
+   fun:do_lookup_x
+   obj:*
+   fun:_dl_lookup_symbol_x
+}
+{
+   avoid_glibc_bug_check_match
+   Memcheck:Addr8
+   fun:check_match.12149
+}
+

tests/acceptance/environment.rb

@@ -5,7 +5,7 @@ require 'file_writer'
 
 class Environment
   attr_reader( :blocksize, :filename1, :filename2, :ip,
-               :port1, :port2, :nbd1, :nbd2, :file1, :file2, :rebind_port1 )
+               :port1, :port2, :nbd1, :nbd2, :file1, :file2 )
 
   def initialize
     @blocksize = 1024
@@ -14,15 +14,25 @@ class Environment
     @ip = "127.0.0.1"
     @available_ports = [*40000..41000] - listening_ports
     @port1 = @available_ports.shift
-    @rebind_port1 = @available_ports.shift
     @port2 = @available_ports.shift
-    @rebind_port2 = @available_ports.shift
-    @nbd1 = FlexNBD.new("../../build/flexnbd", @ip, @port1, @ip, @rebind_port1)
-    @nbd2 = FlexNBD.new("../../build/flexnbd", @ip, @port2, @ip, @rebind_port2)
+    @nbd1 = FlexNBD::FlexNBD.new("../../build/flexnbd", @ip, @port1)
+    @nbd2 = FlexNBD::FlexNBD.new("../../build/flexnbd", @ip, @port2)
 
     @fake_pid = nil
   end
 
+  def prefetch_proxy!
+    @nbd1.prefetch_proxy = true
+    @nbd2.prefetch_proxy = true
+  end
+
+  def proxy1(port=@port2)
+    @nbd1.proxy(@ip, port)
+  end
+  def proxy2(port=@port1)
+    @nbd2.proxy(@ip, port)
+  end
+
 
   def serve1(*acl)
     @nbd1.serve(@filename1, *acl)
@@ -42,6 +52,10 @@ class Environment
   end
 
 
+  def break1
+    @nbd1.break
+  end
+
   def acl1( *acl )
     @nbd1.acl( *acl )
   end
@@ -69,6 +83,14 @@ class Environment
     @nbd1.mirror_unchecked( @nbd2.ip, @nbd2.port, nil, nil, 10 )
   end
 
+  def mirror12_unlink
+    @nbd1.mirror_unlink( @nbd2.ip, @nbd2.port, 2 )
+  end
+
+
+  def write1( data )
+    @nbd1.write( 0, data )
+  end
 
   def writefile1(data)
     @file1 = FileWriter.new(@filename1, @blocksize).write(data)
@@ -111,20 +133,19 @@ class Environment
   end
 
 
-  def run_fake( name, addr, port, rebind_addr = addr, rebind_port = port )
+  def run_fake( name, addr, port, sock=nil )
     fakedir = File.join( File.dirname( __FILE__ ), "fakes" )
-    fake = Dir[File.join( fakedir, name ) + "*"].sort.find { |fn|
+    fakeglob = File.join( fakedir, name ) + "*"
+    fake = Dir[fakeglob].sort.find { |fn|
       File.executable?( fn )
     }
 
-    raise "no fake executable" unless fake
+    raise "no fake executable at #{fakeglob}" unless fake
     raise "no addr" unless addr
     raise "no port" unless port
-    raise "no rebind_addr" unless rebind_addr
-    raise "no rebind_port" unless rebind_port
 
     @fake_pid = fork do
-      exec [fake, addr, port, @nbd1.pid, rebind_addr, rebind_port].map{|x| x.to_s}.join(" ")
+      exec [fake, addr, port, @nbd1.pid, sock].map{|x| x.to_s}.join(" ")
     end
     sleep(0.5)
   end

tests/acceptance/fakes/dest/break_after_hello.rb

@@ -0,0 +1,35 @@
+#!/usr/bin/env ruby
+# encoding: utf-8
+
+# Open a server, accept a client, then cancel the migration by issuing
+# a break command.
+
+require 'flexnbd/fake_dest'
+include FlexNBD
+
+addr, port, src_pid, sock = *ARGV
+server = FakeDest.new( addr, port )
+client = server.accept
+
+ctrl = UNIXSocket.open( sock )
+
+Process.kill("STOP", src_pid.to_i)
+ctrl.write( "break\n" )
+ctrl.close_write
+client.write_hello
+Process.kill("CONT", src_pid.to_i)
+
+fail "Unexpected control response" unless
+  ctrl.read =~ /0: mirror stopped/
+
+client2 = nil
+begin
+  client2 = server.accept( "Expected timeout" )
+  fail "Unexpected reconnection"
+rescue Timeout::Error
+  # expected
+end
+client.close
+
+exit(0)
+

tests/acceptance/fakes/dest/close_after_entrust.rb

@@ -1,29 +0,0 @@
-#!/usr/bin/env ruby
-# encoding: utf-8
-
-# Open a server, accept a client, then we expect a single write
-# followed by an entrust. Disconnect after the entrust. We expect a
-# reconnection followed by a full mirror.
-
-require 'flexnbd/fake_dest'
-include FlexNBD
-
-addr, port, src_pid = *ARGV
-server = FakeDest.new( addr, port )
-client = server.accept
-
-client.write_hello
-write_req = client.read_request
-data = client.read_data( write_req[:len] )
-client.write_reply( write_req[:handle], 0 )
-
-entrust_req = client.read_request
-fail "Not an entrust" unless entrust_req[:type] == 65536
-client.close
-
-client2 = server.accept
-client2.receive_mirror
-
-
-exit(0)
-

tests/acceptance/fakes/dest/close_after_writes.rb

@@ -3,7 +3,8 @@
 
 # Open a server, accept a client, then we expect a single write
 # followed by an entrust.  However, we disconnect after the write so
-# the entrust will fail.  We expect a reconnection.
+# the entrust will fail.  We don't expect a reconnection: the sender
+# can't reliably spot a failed send.
 
 require 'flexnbd/fake_dest'
 include FlexNBD
@@ -21,7 +22,4 @@ client.write_reply( req[:handle], 0 )
 client.close
 Process.kill("CONT", src_pid.to_i)
 
-client2 = server.accept
-client2.close
-
 exit(0)

tests/acceptance/fakes/dest/error_on_entrust.rb

@@ -1,34 +0,0 @@
-#!/usr/bin/env ruby
-# encoding: utf-8
-
-# Receive a mirror, but respond to the entrust with an error.  There's
-# currently no code path in flexnbd which can do this, but we could
-# add one.
-
-require 'flexnbd/fake_dest'
-include FlexNBD
-
-addr, port = *ARGV
-server = FakeDest.new( addr, port )
-client = server.accept
-
-client.write_hello
-loop do
-  req = client.read_request
-  if req[:type] == 1
-    client.read_data( req[:len] )
-    client.write_reply( req[:handle] )
-  else
-    client.write_reply( req[:handle], 1 )
-    break
-  end
-end
-
-client.close
-
-client2 = server.accept( "Timed out waiting for a reconnection" )
-
-client2.close
-server.close
-
-exit(0)

tests/acceptance/fakes/dest/hang_after_write.rb

@@ -20,7 +20,13 @@ t = Thread.start do
   client2.close
 end
 
-sleep( FlexNBD::MS_REQUEST_LIMIT_SECS + 2 )
+sleep_time = if ENV.has_key?('FLEXNBD_MS_REQUEST_LIMIT_SECS')
+  ENV['FLEXNBD_MS_REQUEST_LIMIT_SECS'].to_f
+else
+  FlexNBD::MS_REQUEST_LIMIT_SECS
+end
+
+sleep( sleep_time + 2.0 )
 client1.close
 
 t.join

tests/acceptance/fakes/dest/sigterm_after_hello.rb

@@ -0,0 +1,19 @@
+#!/usr/bin/env ruby
+
+# Wait for a sender connection, send a correct hello, then sigterm the
+# sender.  We expect the sender to exit with status of 6, which is
+# enforced in the test.
+
+require 'flexnbd/fake_dest'
+include FlexNBD
+
+addr, port, pid = *ARGV
+server = FakeDest.new( addr, port )
+client = server.accept( "Timed out waiting for a connection" )
+client.write_hello
+
+Process.kill(15, pid.to_i)
+
+client.close
+server.close
+exit 0

tests/acceptance/fakes/source/close_after_entrust.rb

@@ -3,8 +3,8 @@
 # Connect, send a migration, entrust then *immediately* disconnect.
 # This simulates a client which fails while the client is blocked.
 #
-# We attempt to reconnect immediately afterwards to prove that we can
-# retry the mirroring.
+# In this situation we expect the destination to quit with an error
+# status.
 
 require 'flexnbd/fake_source'
 include FlexNBD
@@ -28,7 +28,11 @@ system "kill -CONT #{srv_pid}"
 
 sleep(0.25)
 
-client2 = FakeSource.new( addr, port, "Timed out reconnecting" )
-client2.close
+begin
+  client2 = FakeSource.new( addr, port, "Expected timeout" )
+  fail "Unexpected reconnection"
+rescue Timeout::Error
+  # expected
+end
 
 exit(0)

tests/acceptance/fakes/source/close_after_entrust_reply.rb

@@ -1,15 +1,14 @@
 #!/usr/bin/env ruby
 
-# Connect, send a migration, entrust then *immediately* disconnect.
+# Connect, send a migration, entrust, read the reply, then disconnect.
 # This simulates a client which fails while the client is blocked.
 #
-# We attempt to reconnect immediately afterwards to prove that we can
-# retry the mirroring.
+# We expect the destination to quit with an error status.
 
 require 'flexnbd/fake_source'
 include FlexNBD
 
-addr, port, srv_pid, rebind_addr, rebind_port = *ARGV
+addr, port, srv_pid = *ARGV
 
 client = FakeSource.new( addr, port, "Timed out connecting" )
 client.read_hello
@@ -22,11 +21,13 @@ client.close
 
 sleep(0.25)
 
-client2 = FakeSource.new( addr, port, "Timed out reconnecting to mirror" )
-client2.send_mirror
 
-sleep(1)
-client3 = FakeSource.new( rebind_addr, rebind_port, "Timed out reconnecting to read" )
-client3.close
+begin
+  client2 = FakeSource.new( addr, port, "Expected timeout" )
+  fail "Unexpected reconnection"
+rescue Timeout::Error
+  # expected
+end
 
 exit(0)
+

tests/acceptance/fakes/source/close_after_write.rb

@@ -12,10 +12,11 @@ addr, port, srv_pid = *ARGV
 
 client = FakeSource.new( addr, port, "Timed out connecting" )
 client.read_hello
-Process.kill( "STOP", srv_pid.to_i )
+
+system "kill -STOP #{srv_pid}"
 client.write_write_request( 0, 8 )
 client.close
-Process.kill( "CONT", srv_pid.to_i )
+system "kill -CONT #{srv_pid}"
 
 # This sleep ensures that we don't return control to the test runner
 # too soon, giving the flexnbd process time to fall over if it's going

tests/acceptance/fakes/source/close_after_write_data.rb

@@ -13,13 +13,13 @@ addr, port, srv_pid = *ARGV
 client = FakeSource.new( addr, port, "Timed out connecting" )
 client.read_hello
 
-Process.kill( "STOP", srv_pid.to_i )
+system "kill -STOP #{srv_pid}"
 
 client.write_write_request( 0, 8 )
 client.write_data( "12345678" )
 client.close
 
-Process.kill( "CONT", srv_pid.to_i )
+system "kill -CONT #{srv_pid}"
 
 # This sleep ensures that we don't return control to the test runner
 # too soon, giving the flexnbd process time to fall over if it's going

tests/acceptance/fakes/source/connect_from_banned_ip.rb

@@ -13,10 +13,8 @@ addr, port = *ARGV
 
 client = FakeSource.new( addr, port, "Timed out connecting", "127.0.0.6" )
 sleep( 0.25 )
-client.ensure_disconnected
 
+rsp = client.disconnected? ? 0 : 1
 client.close
-exit(0)
-
-
+exit(rsp)
 

tests/acceptance/fakes/source/sigterm_after_hello.rb

@@ -0,0 +1,20 @@
+#!/usr/bin/env ruby
+
+# Connect to the listener, wait for the hello, then sigterm the
+# listener.  We expect the listener to exit with a status of 6, which
+# is enforced in the test.
+
+require 'flexnbd/fake_source'
+include FlexNBD
+
+addr, port, pid = *ARGV
+
+client = FakeSource.new( addr, port, "Timed out connecting." )
+client.read_hello
+
+Process.kill( "TERM", pid.to_i )
+
+sleep(0.2)
+client.close
+
+exit(0)

tests/acceptance/fakes/source/successful_transfer.rb

@@ -1,29 +1,18 @@
 #!/usr/bin/env ruby
 
-# Successfully send a migration, but squat on the IP and port which
-# the destination wants to rebind to.  The destination should retry
-# every second, so we give it up then attempt to connect to the new
-# server.
+# Successfully send a migration.  This test just makes sure that the
+# happy path is covered.  We expect the destination to quit with a
+# success status.
 
 require 'flexnbd/fake_source'
 include FlexNBD
 
 addr, port, srv_pid, newaddr, newport = *ARGV
 
-squatter = TCPServer.open( newaddr, newport.to_i )
-
 client  = FakeSource.new( addr, port, "Timed out connecting" )
 client.send_mirror()
 
 sleep(1)
 
-squatter.close()
-
-sleep(1)
-
-client2 = FakeSource.new( newaddr, newport.to_i, "Timed out reconnecting" )
-client2.read_hello
-client2.read( 0, 8 )
-client2.close
 
 exit( 0 )

tests/acceptance/file_writer.rb

@@ -8,6 +8,10 @@ class FileWriter
     @pattern = ""
   end
 
+  def size
+    @blocksize * @pattern.split("").size
+  end
+
   # We write in fixed block sizes, given by "blocksize"
   #    _ means skip a block
   #    0 means write a block full of zeroes

tests/acceptance/flexnbd.rb

@@ -21,7 +21,7 @@ class ValgrindExecutor
   attr_reader :pid
 
   def run( cmd )
-    @pid = fork do exec "valgrind --track-origins=yes #{cmd}" end
+    @pid = fork do exec "valgrind --track-origins=yes --suppressions=custom.supp #{cmd}" end
   end
 end # class ValgrindExecutor
 
@@ -97,7 +97,9 @@ class ValgrindKillingExecutor
       when "line"
         @error.add_line( @text ) if @found
       when "error", "stack"
-        @killer.call( @error )
+        if @found
+          @killer.call( @error )
+        end
       when "pid"
         @error.pid=@text
       end
@@ -129,18 +131,18 @@ class ValgrindKillingExecutor
 
   def run( cmd )
     @io_r, io_w = IO.pipe
-    @pid = fork do exec( "valgrind --xml=yes --xml-fd=#{io_w.fileno} " + cmd ) end
+    @pid = fork do exec( "valgrind --suppressions=custom.supp --xml=yes --xml-fd=#{io_w.fileno} " + cmd ) end
     launch_watch_thread( @pid, @io_r )
     @pid
   end
 
 
   def call( err )
-    Process.kill( "KILL", @pid )
     $stderr.puts "*"*72
     $stderr.puts "* Valgrind error spotted:"
     $stderr.puts err.to_s.split("\n").map{|s| "  #{s}"}
     $stderr.puts "*"*72
+    Process.kill( "KILL", @pid )
     exit(1)
   end
 
@@ -163,305 +165,405 @@ class ValgrindKillingExecutor
 end # class ValgrindExecutor
 
 
-# Noddy test class to exercise FlexNBD from the outside for testing.
-#
-class FlexNBD
-  attr_reader :bin, :ctrl, :pid, :ip, :port, :rebind_ip, :rebind_port
+module FlexNBD
+  # Noddy test class to exercise FlexNBD from the outside for testing.
+  #
+  class FlexNBD
+    attr_reader :bin, :ctrl, :pid, :ip, :port
 
-  class << self
-    def counter
-      Dir['tmp/*'].select{|f| File.file?(f)}.length + 1
-    end
-  end
-
-  def pick_executor
-    kls = if ENV['VALGRIND']
-      if ENV['VALGRIND'] =~ /kill/
-        ValgrindKillingExecutor
-      else
-        ValgrindExecutor
+    class << self
+      def counter
+        Dir['tmp/*'].select{|f| File.file?(f)}.length + 1
       end
-    else
-      Executor
     end
-  end
 
-
-  def build_debug_opt
-    if @do_debug
-      "--verbose"
-    else
-      "--quiet"
+    def pick_executor
+      kls = if ENV['VALGRIND']
+              if ENV['VALGRIND'] =~ /kill/
+                ValgrindKillingExecutor
+              else
+                ValgrindExecutor
+              end
+            else
+              Executor
+            end
     end
-  end
-
-  def initialize(bin, ip, port, rebind_ip = ip, rebind_port = port)
-    @bin  = bin
-    @do_debug = ENV['DEBUG']
-    @debug = build_debug_opt
-    raise "#{bin} not executable" unless File.executable?(bin)
-    @executor = pick_executor.new
-    @ctrl = "/tmp/.flexnbd.ctrl.#{Time.now.to_i}.#{rand}"
-    @ip = ip
-    @port = port
-    @rebind_ip = rebind_ip
-    @rebind_port = rebind_port
-    @kill = []
-  end
 
 
-  def debug?
-    !!@do_debug
-  end
+    def build_debug_opt
+      if @do_debug
+        "--verbose"
+      else
+        "--quiet"
+      end
+    end
 
-  def debug( msg )
-    $stderr.puts msg if debug?
-  end
+    attr_accessor :prefetch_proxy
+
+    def initialize( bin, ip, port )
+      @bin  = bin
+      @do_debug = ENV['DEBUG']
+      @debug = build_debug_opt
+      raise "#{bin} not executable" unless File.executable?(bin)
+      @executor = pick_executor.new
+      @ctrl = "/tmp/.flexnbd.ctrl.#{Time.now.to_i}.#{rand}"
+      @ip = ip
+      @port = port
+      @kill = []
+      @prefetch_proxy = false
+    end
 
 
-  def serve_cmd( file, acl )
-    "#{bin} serve "\
-      "--addr #{ip} "\
-      "--port #{port} "\
-      "--file #{file} "\
-      "--sock #{ctrl} "\
-      "#{@debug} "\
-      "#{acl.join(' ')}"
-  end
+    def debug?
+      !!@do_debug
+    end
+
+    def debug( msg )
+      $stderr.puts msg if debug?
+    end
 
 
-  def listen_cmd( file, acl )
-    "#{bin} listen "\
-      "--addr #{ip} "\
-      "--port #{port} "\
-      "--file #{file} "\
-      "--rebind-addr #{rebind_ip} " \
-      "--rebind-port #{rebind_port} " \
-      "--sock #{ctrl} "\
-      "#{@debug} "\
-      "#{acl.join(' ')}"
-  end
+    def serve_cmd( file, acl )
+      "#{bin} serve "\
+        "--addr #{ip} "\
+        "--port #{port} "\
+        "--file #{file} "\
+        "--sock #{ctrl} "\
+        "#{@debug} "\
+        "#{acl.join(' ')}"
+    end
 
 
-  def read_cmd( offset, length )
-    "#{bin} read "\
-      "--addr #{ip} "\
-      "--port #{port} "\
-      "--from #{offset} "\
-      "#{@debug} "\
-      "--size #{length}"
-  end
+    def listen_cmd( file, acl )
+      "#{bin} listen "\
+        "--addr #{ip} "\
+        "--port #{port} "\
+        "--file #{file} "\
+        "--sock #{ctrl} "\
+        "#{@debug} "\
+        "#{acl.join(' ')}"
+    end
+
+    def proxy_cmd( connect_ip, connect_port )
+      "#{bin}-proxy "\
+        "--addr #{ip} "\
+        "--port #{port} "\
+        "--conn-addr #{connect_ip} "\
+        "--conn-port #{connect_port} "\
+        "#{prefetch_proxy ? "--cache " : ""}"\
+        "#{@debug}"
+    end
 
 
-  def write_cmd( offset, data )
-    "#{bin} write "\
-      "--addr #{ip} "\
-      "--port #{port} "\
-      "--from #{offset} "\
-      "#{@debug} "\
-      "--size #{data.length}"
-  end
+    def read_cmd( offset, length )
+      "#{bin} read "\
+        "--addr #{ip} "\
+        "--port #{port} "\
+        "--from #{offset} "\
+        "#{@debug} "\
+        "--size #{length}"
+    end
 
 
-  def mirror_cmd(dest_ip, dest_port)
-    "#{@bin} mirror "\
+    def write_cmd( offset, data )
+      "#{bin} write "\
+        "--addr #{ip} "\
+        "--port #{port} "\
+        "--from #{offset} "\
+        "#{@debug} "\
+        "--size #{data.length}"
+    end
+
+
+    def base_mirror_opts( dest_ip, dest_port )
       "--addr #{dest_ip} "\
-      "--port #{dest_port} "\
-      "--sock #{ctrl} "\
-      "#{@debug} "
-  end
-
-
-  def status_cmd
-    "#{@bin} status "\
-      "--sock #{ctrl} "\
-      "#{@debug}"
-  end
-
-  def acl_cmd( *acl )
-    "#{@bin} acl " \
-      "--sock #{ctrl} "\
-      "#{@debug} "\
-      "#{acl.join " "}"
-  end
-
-
-  def run_serve_cmd(cmd)
-    File.unlink(ctrl) if File.exists?(ctrl)
-    debug( cmd )
-
-    @pid = @executor.run( cmd )
-    start_wait_thread( @pid )
-
-    while !File.socket?(ctrl)
-      pid, status = Process.wait2(@pid, Process::WNOHANG)
-      raise "server did not start (#{cmd})" if pid
-      sleep 0.1
+        "--port #{dest_port} "\
+        "--sock #{ctrl} "\
+    end
+
+    def unlink_mirror_opts( dest_ip, dest_port )
+      "#{base_mirror_opts( dest_ip, dest_port )} "\
+        "--unlink "
+    end
+
+    def base_mirror_cmd( opts )
+      "#{@bin} mirror "\
+        "#{opts} "\
+        "#{@debug}"
+    end
+
+    def mirror_cmd(dest_ip, dest_port)
+      base_mirror_cmd( base_mirror_opts( dest_ip, dest_port ) )
+    end
+
+    def mirror_unlink_cmd( dest_ip, dest_port )
+      base_mirror_cmd( unlink_mirror_opts( dest_ip, dest_port ) )
+    end
+
+    def break_cmd
+      "#{@bin} break "\
+        "--sock #{ctrl} "\
+        "#{@debug}"
+    end
+
+    def status_cmd
+      "#{@bin} status "\
+        "--sock #{ctrl} "\
+        "#{@debug}"
+    end
+
+    def acl_cmd( *acl )
+      "#{@bin} acl " \
+        "--sock #{ctrl} "\
+        "#{@debug} "\
+        "#{acl.join " "}"
     end
-    at_exit { kill }
-  end
-  private :run_serve_cmd
 
 
-  def serve( file, *acl)
-    run_serve_cmd( serve_cmd( file, acl ) )
-  end
+    def run_serve_cmd(cmd)
+      File.unlink(ctrl) if File.exists?(ctrl)
+      debug( cmd )
 
-  def listen(file, *acl)
-    run_serve_cmd( listen_cmd( file, acl ) )
-  end
+      @pid = @executor.run( cmd )
+
+      while !File.socket?(ctrl)
+        pid, status = Process.wait2(@pid, Process::WNOHANG)
+        raise "server did not start (#{cmd})" if pid
+        sleep 0.1
+      end
 
 
-  def start_wait_thread( pid )
-    @wait_thread = Thread.start do
-      _, status = Process.waitpid2( pid )
+      start_wait_thread( @pid )
+      at_exit { kill }
+    end
+    private :run_serve_cmd
 
-      if @kill
-        fail "flexnbd quit with a bad status: #{status.exitstatus}" unless
-          @kill.include? status.exitstatus
+
+    def serve( file, *acl)
+      cmd = serve_cmd( file, acl )
+      run_serve_cmd( cmd )
+      sleep( 0.2 ) until File.exists?( ctrl )
+    end
+
+
+    def listen(file, *acl)
+      run_serve_cmd( listen_cmd( file, acl ) )
+    end
+
+    def tcp_server_open?
+      # raises if the other side doesn't accept()
+      sock = TCPSocket.new(ip, port) rescue nil
+
+      success = !!sock
+      ( sock.close rescue nil) if sock
+      success
+    end
+
+    def proxy( connect_ip, connect_port )
+      cmd = proxy_cmd( connect_ip, connect_port )
+      debug( cmd )
+
+      @pid = @executor.run( cmd )
+
+      until tcp_server_open?
+        pid, status = Process.wait2(@pid, Process::WNOHANG)
+        raise "server did not start (#{cmd})" if pid
+        sleep 0.1
+      end
+
+      start_wait_thread( @pid )
+      at_exit { kill }
+    end
+
+
+    def start_wait_thread( pid )
+      @wait_thread = Thread.start do
+        _, status = Process.waitpid2( pid )
+
+        if @kill
+          if status.signaled?
+            fail "flexnbd quit with a bad signal: #{status.inspect}" unless
+            @kill.include? status.termsig
+          else
+            fail "flexnbd quit with a bad status: #{status.inspect}" unless
+            @kill.include? status.exitstatus
+          end
+        else
+          $stderr.puts "flexnbd #{self.pid} quit"
+          fail "flexnbd #{self.pid} quit early with status #{status.to_i}"
+        end
+      end
+    end
+
+
+    def can_die(*status)
+      status = [0] if status.empty?
+      @kill += status
+    end
+
+    def kill
+      # At this point, to a certain degree we don't care what the exit
+      # status is
+      can_die(1)
+      if @pid
+        begin
+          Process.kill("INT", @pid)
+        rescue Errno::ESRCH => e
+          # already dead.  Presumably this means it went away after a
+          # can_die() call.
+        end
+      end
+      @wait_thread.join if @wait_thread
+    end
+
+    def read(offset, length)
+      cmd = read_cmd( offset, length )
+      debug( cmd )
+
+      IO.popen(cmd) do |fh|
+        return fh.read
+      end
+      raise IOError.new "NBD read failed" unless $?.success?
+      out
+    end
+
+    def write(offset, data)
+      cmd = write_cmd( offset, data )
+      debug( cmd )
+
+      IO.popen(cmd, "w") do |fh|
+        fh.write(data)
+      end
+      raise IOError.new "NBD write failed" unless $?.success?
+      nil
+    end
+
+
+    def join
+      @wait_thread.join
+    end
+
+
+    def mirror_unchecked( dest_ip, dest_port, bandwidth=nil, action=nil, timeout=nil )
+      cmd = mirror_cmd( dest_ip, dest_port)
+      debug( cmd )
+
+      maybe_timeout( cmd, timeout )
+    end
+
+
+    def mirror_unlink( dest_ip, dest_port, timeout=nil )
+      cmd = mirror_unlink_cmd( dest_ip, dest_port )
+      debug( cmd )
+
+      maybe_timeout( cmd, timeout )
+    end
+
+
+    def maybe_timeout(cmd, timeout=nil )
+      stdout, stderr = "",""
+      stat = nil
+      run = Proc.new do
+        # Ruby 1.9 changed the popen3 api. instead of 3 args, the block
+        # gets 4. Not only that, but it no longer sets $?, so we have to
+        # go elsewhere for the process' exit status.
+        Open3.popen3( cmd ) do |io_in, io_out, io_err, maybe_thr|
+          io_in.close
+          stdout.replace io_out.read
+          stderr.replace io_err.read
+          stat = maybe_thr.value if maybe_thr
+        end
+        stat ||= $?
+      end
+
+      if timeout
+        Timeout.timeout(timeout, &run)
       else
-        $stderr.puts "flexnbd #{self.pid} quit"
-        fail "flexnbd #{self.pid} quit early with status #{status.to_i}"
+        run.call
       end
+
+      [stdout, stderr, stat]
     end
-  end
 
 
-  def can_die(*status)
-    status = [0] if status.empty?
-    @kill += status
-  end
+    def mirror(dest_ip, dest_port, bandwidth=nil, action=nil)
+      stdout, stderr, status = mirror_unchecked( dest_ip, dest_port, bandwidth, action )
+      raise IOError.new( "Migrate command failed\n" + stderr) unless status.success?
 
-  def kill
-    # At this point, to a certain degree we don't care what the exit
-    # status is
-    can_die(1)
-    if @pid
-      begin
-        Process.kill("INT", @pid)
-      rescue Errno::ESRCH => e
-        # already dead.  Presumably this means it went away after a
-        # can_die() call.
-      end
+      stdout
     end
-    @wait_thread.join if @wait_thread
-  end
 
-  def read(offset, length)
-    cmd = read_cmd( offset, length )
-    debug( cmd )
 
-    IO.popen(cmd) do |fh|
-      return fh.read
+
+    def break(timeout=nil)
+      cmd = break_cmd
+      debug( cmd )
+
+      maybe_timeout( cmd, timeout )
     end
-    raise IOError.new "NBD read failed" unless $?.success?
-    out
-  end
 
-  def write(offset, data)
-    cmd = write_cmd( offset, data )
-    debug( cmd )
 
-    IO.popen(cmd, "w") do |fh|
-      fh.write(data)
+    def acl(*acl)
+      cmd = acl_cmd( *acl )
+      debug( cmd )
+
+      maybe_timeout( cmd, 2 )
     end
-    raise IOError.new "NBD write failed" unless $?.success?
-    nil
-  end
 
 
-  def join
-    @wait_thread.join
-  end
+    def status( timeout = nil )
+      cmd = status_cmd()
+      debug( cmd )
+
+      o,e = maybe_timeout( cmd, timeout )
+
+      [parse_status(o), e]
+    end
 
 
-  def mirror_unchecked( dest_ip, dest_port, bandwidth=nil, action=nil, timeout=nil )
-    cmd = mirror_cmd( dest_ip, dest_port)
-    debug( cmd )
-
-    maybe_timeout( cmd, timeout )
-  end
+    def launched?
+      !!@pid
+    end
 
 
-  def maybe_timeout(cmd, timeout=nil )
-    stdout, stderr = "",""
-    run = Proc.new do
-      Open3.popen3( cmd ) do |io_in, io_out, io_err|
-        io_in.close
-        stdout.replace io_out.read
-        stderr.replace io_err.read
+    def paused
+      Process.kill( "STOP", @pid )
+      yield
+    ensure
+      Process.kill( "CONT", @pid )
+    end
+
+
+    protected
+    def control_command(*args)
+      raise "Server not running" unless @pid
+      args = args.compact
+      UNIXSocket.open(@ctrl) do |u|
+        u.write(args.join("\n") + "\n")
+        code, message = u.readline.split(": ", 2)
+        return [code, message]
       end
     end
 
-    if timeout
-      Timeout.timeout(timeout, &run)
-    else
-      run.call
+
+    def parse_status( status )
+      hsh = {}
+
+      status.split(" ").each do |part|
+        next if part.strip.empty?
+        a,b = part.split("=")
+        b.strip!
+        b = true if b == "true"
+        b = false if b == "false"
+
+        hsh[a.strip] = b
+      end
+
+      hsh
     end
 
-    [stdout, stderr]
+
   end
 
-
-  def mirror(dest_ip, dest_port, bandwidth=nil, action=nil)
-    stdout, stderr = mirror_unchecked( dest_ip, dest_port, bandwidth, action )
-    raise IOError.new( "Migrate command failed\n" + stderr) unless $?.success?
-
-    stdout
-  end
-
-
-  def acl(*acl)
-    cmd = acl_cmd( *acl )
-    debug( cmd )
-
-    maybe_timeout( cmd, 2 )
-  end
-
-
-  def status( timeout = nil )
-    cmd = status_cmd()
-    debug( cmd )
-
-    o,e = maybe_timeout( cmd, timeout )
-
-    [parse_status(o), e]
-  end
-
-
-  def launched?
-    !!@pid
-  end
-
-
-  protected
-  def control_command(*args)
-    raise "Server not running" unless @pid
-    args = args.compact
-    UNIXSocket.open(@ctrl) do |u|
-      u.write(args.join("\n") + "\n")
-      code, message = u.readline.split(": ", 2)
-      return [code, message]
-    end
-  end
-
-
-  def parse_status( status )
-    hsh = {}
-
-    status.split(" ").each do |part|
-      next if part.strip.empty?
-      a,b = part.split("=")
-      b.strip!
-      b = true if b == "true"
-      b = false if b == "false"
-
-      hsh[a.strip] = b
-    end
-
-    hsh
-  end
-
-
 end
 

tests/acceptance/flexnbd/constants.rb

@@ -2,6 +2,14 @@
 
 module FlexNBD
 
+  def self.binary( str )
+    if str.respond_to? :force_encoding
+      str.force_encoding "ASCII-8BIT"
+    else
+      str
+    end
+  end
+
   # eeevil is his one and only name...
   def self.read_constants
     parents = []
@@ -17,14 +25,14 @@ module FlexNBD
 
     fail "No source root!" unless source_root
 
-    headers = Dir[File.join( source_root, "src", "*.h" ) ]
+    headers = Dir[File.join( source_root, "src", "{common,proxy,server}","*.h" ) ]
 
     headers.each do |header_filename|
       txt_lines = File.readlines( header_filename )
       txt_lines.each do |line|
         if line =~ /^#\s*define\s+([A-Z0-9_]+)\s+(\d+)\s*$/
           # Bodge until I can figure out what to do with #ifdefs
-          const_set($1, $2.to_i) unless constants.include?( $1 )
+          const_set($1, $2.to_i) unless const_defined?( $1 )
         end
       end
     end
@@ -32,6 +40,9 @@ module FlexNBD
   end
 
   read_constants()
+
+  REQUEST_MAGIC = binary("\x25\x60\x95\x13") unless defined?(REQUEST_MAGIC)
+  REPLY_MAGIC = binary("\x67\x44\x66\x98") unless defined?(REPLY_MAGIC)
+
 end # module FlexNBD
 
-

tests/acceptance/flexnbd/fake_dest.rb

@@ -56,8 +56,6 @@ module FlexNBD
         }
       end
 
-      REPLY_MAGIC="\x67\x44\x66\x98"
-
       def write_error( handle )
         write_reply( handle, 1 )
       end
@@ -76,7 +74,7 @@ module FlexNBD
         if opts[:magic] == :wrong
           write_rand( @sock, 4 )
         else
-          @sock.write( REPLY_MAGIC )
+          @sock.write( ::FlexNBD::REPLY_MAGIC )
         end
 
         @sock.write( [err].pack("N") )
@@ -93,6 +91,10 @@ module FlexNBD
         @sock.read( len )
       end
 
+      def write_data( len )
+        @sock.write( len )
+      end
+
 
       def self.parse_be64(str)
         raise "String is the wrong length: 8 bytes expected (#{str.length} received)" unless
@@ -136,7 +138,7 @@ module FlexNBD
     end
 
 
-    def accept( err_msg = "Timed out waiting for a connection", timeout = 2)
+    def accept( err_msg = "Timed out waiting for a connection", timeout = 5)
       client_sock = nil
 
       begin
@@ -161,3 +163,4 @@ module FlexNBD
 
   end # module FakeDest
 end # module FlexNBD
+

tests/acceptance/flexnbd/fake_source.rb

@@ -9,10 +9,16 @@ module FlexNBD
 
     def initialize( addr, port, err_msg, source_addr=nil, source_port=0 )
       timing_out( 2, err_msg ) do
-        @sock = if source_addr
-          TCPSocket.new( addr, port, source_addr, source_port )
-        else 
-          TCPSocket.new( addr, port )
+        begin
+          @sock = if source_addr
+                    TCPSocket.new( addr, port, source_addr, source_port )
+                  else
+                    TCPSocket.new( addr, port )
+                  end
+        rescue Errno::ECONNREFUSED
+          $stderr.puts "Connection refused, retrying"
+          sleep(0.2)
+          retry
         end
       end
     end
@@ -24,7 +30,7 @@ module FlexNBD
 
 
     def read_hello()
-      timing_out( FlexNBD::MS_HELLO_TIME_SECS,
+      timing_out( ::FlexNBD::MS_HELLO_TIME_SECS,
                   "Timed out waiting for hello." ) do
         fail "No hello." unless (hello = @sock.read( 152 )) &&
           hello.length==152
@@ -41,15 +47,14 @@ module FlexNBD
     end
 
 
-    def send_request( type, handle="myhandle", from=0, len=0 )
+    def send_request( type, handle="myhandle", from=0, len=0, magic=REQUEST_MAGIC )
       fail "Bad handle" unless handle.length == 8
 
-      @sock.write( "\x25\x60\x95\x13" )
+      @sock.write( magic )
       @sock.write( [type].pack( 'N' ) )
       @sock.write( handle )
-      @sock.write( "\x0"*4 )
-      @sock.write( [from].pack( 'N' ) )
-      @sock.write( [len ].pack( 'N' ) )
+      @sock.write( [n64( from )].pack( 'q' ) )
+      @sock.write( [len].pack( 'N' ) )
     end
 
 
@@ -90,16 +95,19 @@ module FlexNBD
 
     def send_mirror
       read_hello()
-      write_write_request( 0, 8 )
-      write_data( "12345678" )
-      read_response()
-      write_entrust_request()
+      write( 0, "12345678" )
       read_response()
       write_disconnect_request()
       close()
     end
 
 
+    def write( from, data )
+      write_write_request( from, data.length )
+      write_data( data )
+    end
+
+
     def read_response
       magic = @sock.read(4)
       error_s = @sock.read(4)
@@ -113,10 +121,10 @@ module FlexNBD
     end
 
 
-    def ensure_disconnected
-      Timeout.timeout( 2 ) do
-        @sock.read(1)
-      end
+    def disconnected?
+      result = nil
+      Timeout.timeout( 2 ) { result = ( @sock.read(1) == nil ) }
+      result
     end
 
 
@@ -131,6 +139,22 @@ module FlexNBD
       end
     end
 
+    private
+
+    # take a 64-bit number, turn it upside down (due to :
+    #   http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/11920
+    # )
+    def n64(b)
+      ((b & 0xff00000000000000) >> 56) |
+      ((b & 0x00ff000000000000) >> 40) |
+      ((b & 0x0000ff0000000000) >> 24) |
+      ((b & 0x000000ff00000000) >> 8)  |
+      ((b & 0x00000000ff000000) << 8)  |
+      ((b & 0x0000000000ff0000) << 24) |
+      ((b & 0x000000000000ff00) << 40) |
+      ((b & 0x00000000000000ff) << 56)
+    end
 
   end # class FakeSource
 end # module FlexNBD
+

tests/acceptance/proxy_tests.rb

@@ -0,0 +1,194 @@
+# encoding: utf-8
+require 'flexnbd/fake_source'
+require 'flexnbd/fake_dest'
+
+module ProxyTests
+  def b
+    "\xFF".b
+  end
+
+  def with_proxied_client( override_size = nil )
+    @env.serve1 unless @server_up
+    @env.proxy2 unless @proxy_up
+    @env.nbd2.can_die(0)
+    client = FlexNBD::FakeSource.new(@env.ip, @env.port2, "Couldn't connect to proxy")
+    begin
+
+      result = client.read_hello
+      assert_equal "NBDMAGIC", result[:magic]
+      assert_equal override_size || @env.file1.size, result[:size]
+
+      yield client
+    ensure
+      client.close rescue nil
+    end
+  end
+
+  def test_exits_with_error_when_cannot_connect_to_upstream_on_start
+    assert_raises(RuntimeError) { @env.proxy1 }
+  end
+
+  def test_read_requests_successfully_proxied
+    with_proxied_client do |client|
+      (0..3).each do |n|
+        offset = n * 4096
+        client.write_read_request(offset, 4096, "myhandle")
+        rsp = client.read_response
+
+        assert_equal ::FlexNBD::REPLY_MAGIC, rsp[:magic]
+        assert_equal "myhandle", rsp[:handle]
+        assert_equal 0, rsp[:error]
+
+        orig_data = @env.file1.read(offset, 4096)
+        data = client.read_raw(4096)
+
+        assert_equal 4096, orig_data.size
+        assert_equal 4096, data.size
+
+        assert_equal( orig_data, data,
+                      "Returned data does not match on request #{n+1}" )
+      end
+    end
+  end
+
+  def test_write_requests_successfully_proxied
+    with_proxied_client do |client|
+      (0..3).each do |n|
+        offset = n * 4096
+        client.write(offset, b * 4096)
+        rsp = client.read_response
+
+        assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+        assert_equal "myhandle", rsp[:handle]
+        assert_equal 0, rsp[:error]
+
+        data = @env.file1.read(offset, 4096)
+
+        assert_equal( ( b * 4096 ), data, "Data not written correctly (offset is #{n})" )
+      end
+    end
+  end
+
+  def make_fake_server
+    server = FlexNBD::FakeDest.new(@env.ip, @env.port1)
+    @server_up = true
+
+    # We return a thread here because accept() and connect() both block for us
+    Thread.new do
+      sc = server.accept # just tell the supervisor we're up
+      sc.write_hello
+
+      [ server, sc ]
+    end
+  end
+
+  def test_read_request_retried_when_upstream_dies_partway
+    maker = make_fake_server
+
+    with_proxied_client(4096) do |client|
+      server, sc1 = maker.value
+
+      # Send the read request to the proxy
+      client.write_read_request( 0, 4096 )
+
+      # ensure we're given the read request
+      req1 = sc1.read_request
+      assert_equal ::FlexNBD::REQUEST_MAGIC, req1[:magic]
+      assert_equal ::FlexNBD::REQUEST_READ, req1[:type]
+      assert_equal 0, req1[:from]
+      assert_not_equal 0, req1[:len]
+
+      # Kill the server again, now we're sure the read request has been sent once
+      sc1.close
+
+      # We expect the proxy to reconnect without our client doing anything.
+      sc2 = server.accept
+      sc2.write_hello
+
+      # And once reconnected, it should resend an identical request.
+      req2 = sc2.read_request
+      assert_equal req1, req2
+
+      # The reply should be proxied back to the client.
+      sc2.write_reply( req2[:handle] )
+      sc2.write_data( b * 4096 )
+
+      # Check it to make sure it's correct
+      rsp = timeout(15) { client.read_response }
+      assert_equal ::FlexNBD::REPLY_MAGIC, rsp[:magic]
+      assert_equal 0, rsp[:error]
+      assert_equal req1[:handle], rsp[:handle]
+
+      data = client.read_raw( 4096 )
+      assert_equal( (b * 4096), data, "Wrong data returned" )
+
+      sc2.close
+      server.close
+    end
+
+  end
+
+  def test_write_request_retried_when_upstream_dies_partway
+    maker = make_fake_server
+
+    with_proxied_client(4096) do |client|
+      server, sc1 = maker.value
+
+      # Send the read request to the proxy
+      client.write( 0, ( b * 4096 ) )
+
+      # ensure we're given the read request
+      req1 = sc1.read_request
+      assert_equal ::FlexNBD::REQUEST_MAGIC, req1[:magic]
+      assert_equal ::FlexNBD::REQUEST_WRITE, req1[:type]
+      assert_equal 0, req1[:from]
+      assert_equal 4096, req1[:len]
+      data1 = sc1.read_data( 4096 )
+      assert_equal( ( b * 4096 ), data1, "Data not proxied successfully" )
+
+      # Kill the server again, now we're sure the read request has been sent once
+      sc1.close
+
+      # We expect the proxy to reconnect without our client doing anything.
+      sc2 = server.accept
+      sc2.write_hello
+
+      # And once reconnected, it should resend an identical request.
+      req2 = sc2.read_request
+      assert_equal req1, req2
+      data2 = sc2.read_data( 4096 )
+      assert_equal data1, data2
+
+      # The reply should be proxied back to the client.
+      sc2.write_reply( req2[:handle] )
+
+      # Check it to make sure it's correct
+      rsp = timeout(15) { client.read_response }
+      assert_equal ::FlexNBD::REPLY_MAGIC, rsp[:magic]
+      assert_equal 0, rsp[:error]
+      assert_equal req1[:handle], rsp[:handle]
+
+      sc2.close
+      server.close
+    end
+  end
+
+  def test_only_one_client_can_connect_to_proxy_at_a_time
+    with_proxied_client do |client|
+
+      c2 = nil
+      assert_raises(Timeout::Error) do
+        timeout(1) do
+          c2 = FlexNBD::FakeSource.new(@env.ip, @env.port2, "Couldn't connect to proxy (2)")
+          c2.read_hello
+        end
+      end
+      c2.close rescue nil if c2
+    end
+
+
+  end
+
+end
+
+

tests/acceptance/test_dest_error_handling.rb

@@ -21,12 +21,18 @@ class TestDestErrorHandling  < Test::Unit::TestCase
     assert_no_control
   end
 
-
+=begin
+  # This is disabled while CLIENT_MAX_WAIT_SECS is removed
   def test_hello_goes_astray_causes_timeout_error
     run_fake( "source/hang_after_hello" )
     assert_no_control
   end
+=end
 
+  def test_sigterm_has_bad_exit_status
+    @env.nbd1.can_die(1)
+    run_fake( "source/sigterm_after_hello" )
+  end
 
   def test_disconnect_after_hello_causes_error_not_fatal
     run_fake( "source/close_after_hello" )
@@ -58,10 +64,6 @@ class TestDestErrorHandling  < Test::Unit::TestCase
     run_fake( "source/close_after_write" )
   end
 
-  def test_disconnect_before_entrust_reply_causes_error
-    run_fake( "source/close_after_entrust" )
-  end
-
 
   def test_disconnect_before_write_reply_causes_error
     # Note that this is an odd case: writing the reply doesn't fail.
@@ -71,23 +73,16 @@ class TestDestErrorHandling  < Test::Unit::TestCase
   end
 
 
-  def test_disconnect_after_entrust_reply_causes_error
+
+  def test_straight_migration
     @env.nbd1.can_die(0)
-    # This fake runs a failed migration then a succeeding one, so we
-    # expect the destination to take control.
-    run_fake( "source/close_after_entrust_reply" )
-    assert_control
-  end
-
-
-  def test_cant_rebind_retries
     run_fake( "source/successful_transfer" )
   end
 
 
   private
   def run_fake( name )
-    @env.run_fake( name, @env.ip, @env.port1, @env.ip, @env.rebind_port1 )
+    @env.run_fake( name, @env.ip, @env.port1 )
     assert @env.fake_reports_success, "#{name} failed."
   end
 
@@ -105,3 +100,4 @@ class TestDestErrorHandling  < Test::Unit::TestCase
   end
 
 end # class TestDestErrorHandling
+

tests/acceptance/test_happy_path.rb

@@ -2,12 +2,17 @@
 
 require 'test/unit'
 require 'environment'
+require 'flexnbd/constants'
 
 class TestHappyPath < Test::Unit::TestCase
   def setup
     @env = Environment.new
   end
 
+  def bin(str)
+    FlexNBD.binary str
+  end
+
   def teardown
     @env.nbd1.can_die(0)
     @env.nbd2.can_die(0)
@@ -22,13 +27,13 @@ class TestHappyPath < Test::Unit::TestCase
     [0, 12, 63].each do |num|
 
       assert_equal(
-        @env.nbd1.read(num*@env.blocksize, @env.blocksize),
-        @env.file1.read(num*@env.blocksize, @env.blocksize)
+        bin( @env.nbd1.read(num*@env.blocksize, @env.blocksize) ),
+        bin( @env.file1.read(num*@env.blocksize, @env.blocksize) )
       )
     end
 
     [124, 1200, 10028, 25488].each do |num|
-      assert_equal(@env.nbd1.read(num, 4), @env.file1.read(num, 4))
+      assert_equal(bin(@env.nbd1.read(num, 4)), bin(@env.file1.read(num, 4)))
     end
   end
 
@@ -64,25 +69,57 @@ class TestHappyPath < Test::Unit::TestCase
   end
 
 
-  def test_mirror
+  def setup_to_mirror
     @env.writefile1( "f"*4 )
     @env.serve1
 
     @env.writefile2( "0"*4 )
     @env.listen2
-
-    @env.nbd1.can_die
-    stdout, stderr = @env.mirror12
-
-    @env.nbd1.join
-
-    assert_equal(@env.file1.read_original( 0, @env.blocksize ),
-                 @env.file2.read( 0, @env.blocksize ) )
-    assert @env.status2['has_control'], "destination didn't take control"
   end
 
 
+  def test_mirror
+    @env.nbd1.can_die
+    @env.nbd2.can_die(0)
+    setup_to_mirror()
+
+    stdout, stderr = @env.mirror12
+
+    @env.nbd1.join
+    @env.nbd2.join
+
+    assert( File.file?( @env.filename1 ),
+           "The source file was incorrectly deleted")
+    assert_equal(@env.file1.read_original( 0, @env.blocksize ),
+                 @env.file2.read( 0, @env.blocksize ) )
+  end
+
+
+  def test_mirror_unlink
+    @env.nbd1.can_die(0)
+    @env.nbd2.can_die(0)
+    setup_to_mirror()
+
+    assert File.file?( @env.filename1 )
+
+    stdout, stderr = @env.mirror12_unlink
+
+    assert_no_match( /unrecognized/, stderr )
+
+
+    Timeout.timeout(10) do @env.nbd1.join end
+
+    assert !File.file?( @env.filename1 )
+  end
+
+
+
   def test_write_to_high_block
+		# 
+		# This test does not work on 32 bit platforms.
+		#
+		skip("Not relevant on 32-bit platforms") if ( ["a"].pack("p").size < 8 )
+
     # Create a large file, then try to write to somewhere after the 2G boundary
     @env.truncate1 "4G"
     @env.serve1
@@ -92,4 +129,41 @@ class TestHappyPath < Test::Unit::TestCase
     assert_equal "12345678", @env.nbd1.read( 2**31+2**29, 8 )
   end
 
+
+  def test_set_acl
+    # Just check that we get sane feedback here
+    @env.writefile1( "f"*4 )
+    @env.serve1
+
+    _,stderr = @env.acl1("127.0.0.1")
+    assert_no_match( /^(F|E):/, stderr )
+  end
+
+
+  def test_write_more_than_one_run
+    one_mb = 2**20
+    data = "\0" * 256 * one_mb
+
+    File.open(@env.filename1, "wb") do |f| f.write( "1" * 256 * one_mb ) end
+
+    @env.serve1
+    sleep 5
+    @env.write1( data )
+    @env.nbd1.can_die(0)
+    @env.nbd1.kill
+
+    i = 0
+    File.open(@env.filename1, "rb") do |f|
+      while mb = f.read( one_mb )
+        unless "\0"*one_mb == mb
+          msg = "Read non-zeros after offset %x:\n"%(i * one_mb)
+          msg += `hexdump #{@env.filename1} | head -n5`
+          fail msg
+        end
+        i += 1
+      end
+    end
+  end
+
 end
+

tests/acceptance/test_prefetch_proxy_mode.rb

@@ -0,0 +1,22 @@
+require 'test/unit'
+require 'environment'
+require 'proxy_tests'
+
+
+class TestPrefetchProxyMode < Test::Unit::TestCase
+  include ProxyTests
+
+  def setup
+    super
+    @env = Environment.new
+    @env.prefetch_proxy!
+    @env.writefile1( "f" * 16 )
+  end
+
+  def teardown
+    @env.cleanup
+    super
+  end
+end
+
+

tests/acceptance/test_proxy_mode.rb

@@ -0,0 +1,20 @@
+require 'test/unit'
+require 'environment'
+require 'proxy_tests'
+
+
+class TestProxyMode < Test::Unit::TestCase
+  include ProxyTests
+
+  def setup
+    super
+    @env = Environment.new
+    @env.writefile1( "f" * 16 )
+  end
+
+  def teardown
+    @env.cleanup
+    super
+  end
+end
+

tests/acceptance/test_serve_mode.rb

@@ -0,0 +1,110 @@
+require 'test/unit'
+require 'environment'
+require 'flexnbd/fake_source'
+
+class TestServeMode < Test::Unit::TestCase
+
+  def setup
+    super
+    @b = "\xFF".b
+    @env = Environment.new
+    @env.writefile1( "0" )
+    @env.serve1
+  end
+
+  def teardown
+    @env.cleanup
+    super
+  end
+
+  def connect_to_server
+    client = FlexNBD::FakeSource.new(@env.ip, @env.port1, "Connecting to server failed")
+    begin
+      result = client.read_hello
+      assert_equal "NBDMAGIC", result[:magic]
+      assert_equal @env.file1.size, result[:size]
+      yield client
+    ensure
+      client.close rescue nil
+    end
+  end
+
+  def test_bad_request_magic_receives_error_response
+    connect_to_server do |client|
+
+      # replace REQUEST_MAGIC with all 0s to make it look bad
+      client.send_request( 0, "myhandle", 0, 0, "\x00\x00\x00\x00" )
+      rsp = client.read_response
+
+      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+      assert_equal "myhandle", rsp[:handle]
+      assert rsp[:error] != 0, "Server sent success reply back: #{rsp[:error]}"
+
+      # The client should be disconnected now
+      assert client.disconnected?, "Server not disconnected"
+    end
+  end
+
+  def test_long_write_on_top_of_short_write_is_respected
+
+    connect_to_server do |client|
+      # Start with a file of all-zeroes.
+      client.write( 0, "\x00" * @env.file1.size )
+      rsp = client.read_response
+      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+      assert_equal 0, rsp[:error]
+
+      client.write( 0, @b )
+      rsp = client.read_response
+      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+      assert_equal 0, rsp[:error]
+
+      client.write( 0, @b * 2 )
+      rsp = client.read_response
+      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+      assert_equal 0, rsp[:error]
+    end
+
+    assert_equal @b * 2, @env.file1.read( 0, 2 )
+  end
+
+
+  def test_read_request_out_of_bounds_receives_error_response
+    connect_to_server do |client|
+      client.write_read_request( @env.file1.size, 4096 )
+      rsp = client.read_response
+
+      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+      assert_equal "myhandle", rsp[:handle]
+      assert rsp[:error] != 0, "Server sent success reply back: #{rsp[:error]}"
+
+      # Ensure we're not disconnected by sending a request. We don't care about
+      # whether the reply is good or not, here.
+      client.write_read_request( 0, 4096 )
+      rsp = client.read_response
+      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+    end
+  end
+
+  def test_write_request_out_of_bounds_receives_error_response
+    connect_to_server do |client|
+      client.write( @env.file1.size, "\x00" * 4096 )
+      rsp = client.read_response
+
+      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+      assert_equal "myhandle", rsp[:handle]
+      assert rsp[:error] != 0, "Server sent success reply back: #{rsp[:error]}"
+
+      # Ensure we're not disconnected by sending a request. We don't care about
+      # whether the reply is good or not, here.
+      client.write( 0, "\x00" * @env.file1.size )
+      rsp = client.read_response
+      assert_equal FlexNBD::REPLY_MAGIC, rsp[:magic]
+    end
+
+  end
+
+
+
+end
+

tests/acceptance/test_source_error_handling.rb

@@ -7,6 +7,9 @@ require 'environment'
 class TestSourceErrorHandling < Test::Unit::TestCase
 
   def setup
+    @old_env = ENV['FLEXNBD_MS_REQUEST_LIMIT_SECS']
+    ENV['FLEXNBD_MS_REQUEST_LIMIT_SECS'] = "4.0"
+
     @env = Environment.new
     @env.writefile1( "f" * 4 )
     @env.serve1
@@ -16,15 +19,28 @@ class TestSourceErrorHandling < Test::Unit::TestCase
   def teardown
     @env.nbd1.can_die(0)
     @env.cleanup
+    ENV['FLEXNBD_MS_REQUEST_LIMIT_SECS'] = @old_env
+  end
+
+
+  def expect_term_during_migration
+    @env.nbd1.can_die(1,9)
   end
 
 
   def test_failure_to_connect_reported_in_mirror_cmd_response
     stdout, stderr = @env.mirror12_unchecked
+    expect_term_during_migration
     assert_match( /failed to connect/, stderr )
   end
 
 
+  def test_sigterm_after_hello_quits_with_status_of_1
+    expect_term_during_migration
+    run_fake( "dest/sigterm_after_hello" )
+  end
+
+
   def test_destination_hangs_after_connect_reports_error_at_source
     run_fake( "dest/hang_after_connect",
               :err => /Remote server failed to respond/ )
@@ -36,6 +52,7 @@ class TestSourceErrorHandling < Test::Unit::TestCase
               :err => /Mirror was rejected/ )
   end
 
+
   def test_wrong_size_causes_disconnect
     run_fake( "dest/hello_wrong_size",
               :err => /Remote size does not match local size/ )
@@ -43,57 +60,57 @@ class TestSourceErrorHandling < Test::Unit::TestCase
 
 
   def test_wrong_magic_causes_disconnect
+    expect_term_during_migration
     run_fake( "dest/hello_wrong_magic",
               :err => /Mirror was rejected/ )
   end
 
 
   def test_disconnect_after_hello_causes_retry
+    expect_term_during_migration
     run_fake( "dest/close_after_hello",
               :out => /Mirror started/ )
   end
 
 
   def test_write_times_out_causes_retry
+    expect_term_during_migration
     run_fake( "dest/hang_after_write" )
   end
 
 
   def test_rejected_write_causes_retry
+    expect_term_during_migration
     run_fake( "dest/error_on_write" )
   end
 
 
   def test_disconnect_before_write_reply_causes_retry
+    expect_term_during_migration
     run_fake( "dest/close_after_write" )
   end
 
 
   def test_bad_write_reply_causes_retry
+    expect_term_during_migration
     run_fake( "dest/write_wrong_magic" )
   end
 
 
   def test_pre_entrust_disconnect_causes_retry
+    expect_term_during_migration
     run_fake( "dest/close_after_writes" )
   end
 
 
-  def test_post_entrust_disconnect_causes_retry
-    @env.nbd1.can_die(0)
-    run_fake( "dest/close_after_entrust" )
+  def test_cancel_migration
+    run_fake( "dest/break_after_hello" )
   end
 
 
-  def test_entrust_error_causes_retry
-    run_fake( "dest/error_on_entrust" )
-  end
-
-
-
   private
   def run_fake(name, opts = {})
-    @env.run_fake( name, @env.ip, @env.port2 )
+    @env.run_fake( name, @env.ip, @env.port2, @env.nbd1.ctrl )
     stdout, stderr = @env.mirror12_unchecked
     assert_success
     assert_match( opts[:err], stderr ) if opts[:err]

tests/acceptance/test_write_during_migration.rb

@@ -0,0 +1,171 @@
+#!/usr/bin/env ruby
+
+require 'test/unit'
+require 'flexnbd/fake_source'
+require 'socket'
+require 'fileutils'
+require 'tmpdir'
+
+Thread.abort_on_exception = true
+
+class TestWriteDuringMigration < Test::Unit::TestCase
+
+  def setup
+    @flexnbd = File.expand_path("../../build/flexnbd")
+
+    raise "No binary!" unless File.executable?( @flexnbd )
+
+
+    @size = 20*1024*1024 # 20MB
+    @write_data = "foo!" * 2048 # 8K write
+    @source_port = 9990
+    @dest_port = 9991
+    @source_sock = "src.sock"
+    @dest_sock = "dst.sock"
+    @source_file = "src.file"
+    @dest_file = "dst.file"
+  end
+
+
+  def teardown
+    [@dst_proc, @src_proc].each do |pid|
+      if pid
+        Process.kill( "KILL", pid ) rescue nil
+      end
+    end
+  end
+
+  def debug_arg
+    ENV['DEBUG'] ? "--verbose" : ""
+  end
+
+
+  def launch_servers
+    @dst_proc = fork() {
+      cmd = "#{@flexnbd} listen -l 127.0.0.1 -p #{@dest_port} -f #{@dest_file} -s #{@dest_sock} #{debug_arg}"
+      exec cmd
+    }
+
+    @src_proc = fork() {
+      cmd = "#{@flexnbd} serve -l 127.0.0.1 -p #{@source_port} -f #{@source_file} -s #{@source_sock} #{debug_arg}"
+      exec cmd
+    }
+    begin
+      awaiting = nil
+      Timeout.timeout(10) do
+        awaiting = :source
+        sleep 0.1 while !File.exists?( @source_sock )
+        awaiting = :dest
+        sleep 0.1 while !File.exists?( @dest_sock )
+      end
+    rescue Timeout::Error
+      case awaiting
+      when :source
+        fail "Couldn't get a source socket."
+      when :dest
+        fail "Couldn't get a destination socket."
+      else
+        fail "Something went wrong I don't understand."
+      end
+    end
+  end
+
+
+  def make_files()
+    FileUtils.touch(@source_file)
+    File.truncate(@source_file, @size)
+    FileUtils.touch(@dest_file)
+    File.truncate(@dest_file, @size)
+
+    File.open(@source_file, "wb"){|f| f.write "a"*@size }
+  end
+
+
+  def start_mirror
+    UNIXSocket.open(@source_sock) {|sock|
+      sock.write(["mirror", "127.0.0.1", @dest_port.to_s, "exit"].join("\x0A") + "\x0A\x0A")
+      sock.flush
+      rsp = sock.readline
+    }
+  end
+
+
+  def wait_for_quit()
+    Timeout.timeout( 10 ) do
+      start_time =  Time.now
+      dst_result = Process::waitpid2(@dst_proc)
+      src_result = Process::waitpid2(@src_proc)
+    end
+  end
+
+  def source_writer
+    client = FlexNBD::FakeSource.new( "127.0.0.1", @source_port, "Timed out connecting" )
+    offsets = Range.new(0, (@size - @write_data.size) / 4096 ).to_a
+    loop do
+      begin
+        client.write(offsets[rand(offsets.size)] * 4096, @write_data)
+      rescue => err
+        # We expect a broken write at some point, so ignore it
+        break
+      end
+    end
+  end
+
+  def assert_both_sides_identical
+    # puts `md5sum #{@source_file} #{@dest_file}`
+
+    # Ensure each block matches
+    File.open(@source_file, "r") do |source|
+      File.open(@dest_file, "r") do |dest|
+        0.upto( @size / 4096 ) do |block_num|
+          s_data = source.read( 4096 )
+          d_data = dest.read( 4096 )
+
+          assert s_data == d_data, "Block #{block_num} mismatch!"
+
+          source.seek( 4096, IO::SEEK_CUR )
+          dest.seek( 4096, IO::SEEK_CUR )
+        end
+      end
+    end
+  end
+
+  def test_write_during_migration
+    Dir.mktmpdir() do |tmpdir|
+      Dir.chdir( tmpdir ) do
+        make_files()
+
+        launch_servers()
+
+        src_writer = Thread.new { source_writer }
+
+        start_mirror()
+        wait_for_quit()
+        src_writer.join
+        assert_both_sides_identical
+      end
+    end
+  end
+
+  def test_many_clients_during_migration
+    Dir.mktmpdir() do |tmpdir|
+      Dir.chdir( tmpdir ) do
+        make_files()
+
+        launch_servers()
+
+        src_writers_1 = (1..5).collect { Thread.new { source_writer } }
+
+        start_mirror()
+
+        src_writers_2 = (1..5).collect { Thread.new { source_writer } }
+
+        wait_for_quit()
+        ( src_writers_1 + src_writers_2 ).each {|t| t.join }
+        assert_both_sides_identical
+      end
+    end  end
+
+
+end
+

tests/fuzz

@@ -29,7 +29,7 @@ end
 
 @local = File.open(testname_local, "r+")
 
-@serve = FlexNBD.new(binary, "127.0.0.1", 41234)
+@serve = FlexNBD::FlexNBD.new(binary, "127.0.0.1", 41234)
 @serve.serve(testname_serve)
 
 $record = []

tests/unit/check_bitset.c

@@ -2,15 +2,20 @@
 
 #include "bitset.h"
 
+#define assert_bitset_is( map, val ) {\
+	uint64_t *num = (uint64_t*) map->bits; \
+	ck_assert_int_eq( val, *num ); \
+}
+
 START_TEST(test_bit_set)
 {
 	uint64_t num = 0;
-	char *bits = (char*) #
-	
+	bitfield_p bits = (bitfield_p) #
+
 #define TEST_BIT_SET(bit, newvalue) \
 	bit_set(bits, (bit)); \
 	fail_unless(num == (newvalue), "num was %x instead of %x", num, (newvalue));
-	
+
 	TEST_BIT_SET(0, 1);
 	TEST_BIT_SET(1, 3);
 	TEST_BIT_SET(2, 7);
@@ -22,12 +27,12 @@ END_TEST
 START_TEST(test_bit_clear)
 {
 	uint64_t num = 0xffffffffffffffff;
-	char *bits = (char*) #
-	
+	bitfield_p bits = (bitfield_p) #
+
 #define TEST_BIT_CLEAR(bit, newvalue) \
 	bit_clear(bits, (bit)); \
 	fail_unless(num == (newvalue), "num was %x instead of %x", num, (newvalue));
-	
+
 	TEST_BIT_CLEAR(0, 0xfffffffffffffffe);
 	TEST_BIT_CLEAR(1, 0xfffffffffffffffc);
 	TEST_BIT_CLEAR(2, 0xfffffffffffffff8);
@@ -39,8 +44,8 @@ END_TEST
 START_TEST(test_bit_tests)
 {
 	uint64_t num = 0x5555555555555555;
-	char *bits = (char*) #
-	
+	bitfield_p bits = (bitfield_p) #
+
 	fail_unless(bit_has_value(bits, 0, 1), "bit_has_value malfunction");
 	fail_unless(bit_has_value(bits, 1, 0), "bit_has_value malfunction");
 	fail_unless(bit_has_value(bits, 63, 0), "bit_has_value malfunction");
@@ -53,23 +58,23 @@ END_TEST
 
 START_TEST(test_bit_ranges)
 {
-	char buffer[4160];
-	uint64_t  *longs = (unsigned long*) buffer;
+	bitfield_word_t buffer[BIT_WORDS_FOR_SIZE(4160)];
+	uint64_t  *longs = (uint64_t *) buffer;
 	uint64_t i;
-	
+
 	memset(buffer, 0, 4160);
-	
+
 	for (i=0; i<64; i++) {
 		bit_set_range(buffer, i*64, i);
 		fail_unless(
-			longs[i] == (1UL<<i)-1,
+			longs[i] == (1ULL<<i)-1,
 			"longs[%ld] = %lx SHOULD BE %lx",
-			i, longs[i], (1L<<i)-1
+			i, longs[i], (1ULL<<i)-1
 		);
-		
+
 		fail_unless(longs[i+1] == 0, "bit_set_range overshot at i=%d", i);
 	}
-	
+
 	for (i=0; i<64; i++) {
 		bit_clear_range(buffer, i*64, i);
 		fail_unless(longs[i] == 0, "bit_clear_range didn't work at i=%d", i);
@@ -79,23 +84,23 @@ END_TEST
 
 START_TEST(test_bit_runs)
 {
-	char buffer[256];
+	bitfield_word_t buffer[BIT_WORDS_FOR_SIZE(256)];
 	int i, ptr=0, runs[] = {
 		56,97,22,12,83,1,45,80,85,51,64,40,63,67,75,64,94,81,79,62
 	};
-	
+
 	memset(buffer,0,256);
-	
+
 	for (i=0; i < 20; i += 2) {
 		ptr += runs[i];
 		bit_set_range(buffer, ptr, runs[i+1]);
 		ptr += runs[i+1];
 	}
-	
+
 	ptr = 0;
-	
+
 	for (i=0; i < 20; i += 1) {
-		int run = bit_run_count(buffer, ptr, 2048-ptr);
+		int run = bit_run_count(buffer, ptr, 2048-ptr, NULL);
 		fail_unless(
 			run == runs[i],
 			"run %d should have been %d, was %d",
@@ -108,12 +113,12 @@ END_TEST
 
 START_TEST(test_bitset)
 {
-	struct bitset_mapping* map;
+	struct bitset * map;
 	uint64_t *num;
-	
+
 	map = bitset_alloc(6400, 100);
 	num = (uint64_t*) map->bits;
-	
+
 	bitset_set_range(map,0,50);
 	ck_assert_int_eq(1, *num);
 	bitset_set_range(map,99,1);
@@ -126,12 +131,12 @@ START_TEST(test_bitset)
 	ck_assert_int_eq(0xc0ff, *num);
 	bitset_clear_range(map,1499,2);
 	ck_assert_int_eq(255, *num);
-	
+
 	*num = 0;
 	bitset_set_range(map, 1499, 2);
 	bitset_clear_range(map, 1300, 200);
 	ck_assert_int_eq(0x8000, *num);
-	
+
 	*num = 0;
 	bitset_set_range(map, 0, 6400);
 	ck_assert_int_eq(0xffffffffffffffff, *num);
@@ -143,24 +148,41 @@ END_TEST
 
 START_TEST( test_bitset_set )
 {
-	struct bitset_mapping* map;
-	uint64_t *num;
-	
-	map = bitset_alloc(64, 1);
-	num = (uint64_t*) map->bits;
+	struct bitset * map;
+	uint64_t run;
 
-	ck_assert_int_eq( 0x0000000000000000, *num );
+	map = bitset_alloc(64, 1);
+
+	assert_bitset_is( map, 0x0000000000000000 );
 	bitset_set( map );
-	ck_assert_int_eq( 0xffffffffffffffff, *num );
+	assert_bitset_is( map, 0xffffffffffffffff );
+	bitset_free( map );
+
+	map = bitset_alloc( 6400, 100 );
+	assert_bitset_is( map, 0x0000000000000000 );
+	bitset_set( map );
+	assert_bitset_is( map, 0xffffffffffffffff );
+	bitset_free( map );
+
+	// Now do something large and representative
+	map = bitset_alloc( 53687091200, 4096 );
+	bitset_set( map );
+
+	run = bitset_run_count( map, 0, 53687091200 );
+	ck_assert_int_eq( run, 53687091200 );
+	bitset_free( map );
+
+
 }
 END_TEST
 
 
 START_TEST( test_bitset_clear )
 {
-	struct bitset_mapping* map;
+	struct bitset * map;
 	uint64_t *num;
-	
+	uint64_t run;
+
 	map = bitset_alloc(64, 1);
 	num = (uint64_t*) map->bits;
 
@@ -168,26 +190,300 @@ START_TEST( test_bitset_clear )
 	bitset_set( map );
 	bitset_clear( map );
 	ck_assert_int_eq( 0x0000000000000000, *num );
+
+	bitset_free( map );
+
+	// Now do something large and representative
+	map = bitset_alloc( 53687091200, 4096 );
+	bitset_set( map );
+	bitset_clear( map );
+	run = bitset_run_count( map, 0, 53687091200 );
+	ck_assert_int_eq( run, 53687091200 );
+	bitset_free( map );
 }
 END_TEST
 
+START_TEST( test_bitset_set_range )
+{
+	struct bitset* map = bitset_alloc( 64, 1 );
+	assert_bitset_is( map, 0x0000000000000000 );
+
+	bitset_set_range( map, 8, 8 );
+	assert_bitset_is( map, 0x000000000000ff00 );
+
+	bitset_clear( map );
+	assert_bitset_is( map, 0x0000000000000000 );
+	bitset_set_range( map, 0, 0 );
+	assert_bitset_is( map, 0x0000000000000000 );
+
+	bitset_free( map );
+}
+END_TEST
+
+START_TEST( test_bitset_clear_range )
+{
+	struct bitset* map = bitset_alloc( 64, 1 );
+	bitset_set( map );
+	assert_bitset_is( map, 0xffffffffffffffff );
+
+	bitset_clear_range( map, 8, 8 );
+	assert_bitset_is( map, 0xffffffffffff00ff );
+
+	bitset_set( map );
+	assert_bitset_is( map, 0xffffffffffffffff );
+	bitset_clear_range( map, 0, 0 );
+	assert_bitset_is( map, 0xffffffffffffffff );
+
+	bitset_free( map );
+}
+END_TEST
+
+START_TEST( test_bitset_run_count )
+{
+	struct bitset* map = bitset_alloc( 64, 1 );
+	uint64_t run;
+
+	assert_bitset_is( map, 0x0000000000000000 );
+
+	run = bitset_run_count( map, 0, 64 );
+	ck_assert_int_eq( 64, run );
+
+	bitset_set_range( map, 0, 32 );
+	assert_bitset_is( map, 0x00000000ffffffff );
+
+	run = bitset_run_count( map, 0, 64 );
+	ck_assert_int_eq( 32, run );
+
+	run = bitset_run_count( map, 0, 16 );
+	ck_assert_int_eq( 16, run );
+
+	run = bitset_run_count( map, 16, 64 );
+	ck_assert_int_eq( 16, run );
+
+	run = bitset_run_count( map, 31, 64 );
+	ck_assert_int_eq( 1, run );
+
+	run = bitset_run_count( map, 32, 64 );
+	ck_assert_int_eq( 32, run );
+
+	run = bitset_run_count( map, 32, 32 );
+	ck_assert_int_eq( 32, run );
+
+	run = bitset_run_count( map, 32, 16 );
+	ck_assert_int_eq( 16, run );
+
+	bitset_free( map );
+
+	map = bitset_alloc( 6400, 100 );
+	assert_bitset_is( map, 0x0000000000000000 );
+
+	run = bitset_run_count( map, 0, 6400 );
+	ck_assert_int_eq( 6400, run );
+
+	bitset_set_range( map, 0, 3200 );
+
+	run = bitset_run_count( map, 0, 6400 );
+	ck_assert_int_eq( 3200, run );
+
+	run = bitset_run_count( map, 1, 6400 );
+	ck_assert_int_eq( 3199, run );
+
+	run = bitset_run_count( map, 3200, 6400 );
+	ck_assert_int_eq( 3200, run );
+
+	run = bitset_run_count( map, 6500, 6400 );
+	ck_assert_int_eq( 0, run );
+	bitset_free( map );
+
+	// Now do something large and representative
+	map = bitset_alloc( 53687091200, 4096 );
+	bitset_set( map );
+	run = bitset_run_count( map, 0, 53687091200 );
+	ck_assert_int_eq( run, 53687091200 );
+
+	bitset_free( map );
+
+}
+END_TEST
+
+START_TEST( test_bitset_set_range_doesnt_push_to_stream )
+{
+	struct bitset *map = bitset_alloc( 64, 1 );
+	bitset_set_range( map, 0, 64 );
+	ck_assert_int_eq( 0, bitset_stream_size( map ) );
+	bitset_free( map );
+}
+END_TEST
+
+START_TEST( test_bitset_clear_range_doesnt_push_to_stream )
+{
+	struct bitset *map = bitset_alloc( 64, 1 );
+	bitset_clear_range( map, 0, 64 );
+	ck_assert_int_eq( 0, bitset_stream_size( map ) );
+	bitset_free( map );
+}
+END_TEST
+
+START_TEST(test_bitset_enable_stream)
+{
+	struct bitset *map = bitset_alloc( 64, 1 );
+	struct bitset_stream_entry result;
+	memset( &result, 0, sizeof( result ) );
+
+	bitset_enable_stream( map );
+
+	ck_assert_int_eq( 1, map->stream_enabled );
+
+	bitset_stream_dequeue( map, &result );
+
+	ck_assert_int_eq( BITSET_STREAM_ON, result.event );
+	ck_assert_int_eq( 0, result.from );
+	ck_assert_int_eq( 64, result.len );
+
+	bitset_free( map );
+}
+END_TEST
+
+START_TEST(test_bitset_disable_stream)
+{
+	struct bitset *map = bitset_alloc( 64, 1 );
+	struct bitset_stream_entry result;
+	memset( &result, 0, sizeof( result ) );
+
+	bitset_enable_stream( map );
+	bitset_disable_stream( map );
+
+	ck_assert_int_eq( 0, map->stream_enabled );
+	ck_assert_int_eq( 2, bitset_stream_size( map ) );
+
+	bitset_stream_dequeue( map, NULL ); // ON
+	bitset_stream_dequeue( map, &result ); // OFF
+
+	ck_assert_int_eq( BITSET_STREAM_OFF, result.event );
+	ck_assert_int_eq( 0, result.from );
+	ck_assert_int_eq( 64, result.len );
+
+	bitset_free( map );
+}
+END_TEST
+
+START_TEST(test_bitset_stream_with_set_range)
+{
+	struct bitset *map = bitset_alloc( 64, 1 );
+	struct bitset_stream_entry result;
+	memset( &result, 0, sizeof( result ) );
+
+	bitset_enable_stream( map );
+	bitset_set_range( map, 0, 32 );
+
+	ck_assert_int_eq( 2, bitset_stream_size( map ) );
+
+	bitset_stream_dequeue( map, NULL ); // ON
+	bitset_stream_dequeue( map, &result ); // SET
+
+	ck_assert_int_eq( BITSET_STREAM_SET, result.event );
+	ck_assert_int_eq( 0, result.from );
+	ck_assert_int_eq( 32, result.len );
+
+	bitset_free( map );
+}
+END_TEST
+
+START_TEST(test_bitset_stream_with_clear_range)
+{
+	struct bitset *map = bitset_alloc( 64, 1 );
+	struct bitset_stream_entry result;
+	memset( &result, 0, sizeof( result ) );
+
+	bitset_enable_stream( map );
+	bitset_clear_range( map, 0, 32 );
+	ck_assert_int_eq( 2, bitset_stream_size( map ) );
+
+	bitset_stream_dequeue( map, NULL ); // ON
+	bitset_stream_dequeue( map, &result ); // UNSET
+
+	ck_assert_int_eq( BITSET_STREAM_UNSET, result.event );
+	ck_assert_int_eq( 0, result.from );
+	ck_assert_int_eq( 32, result.len );
+
+	bitset_free( map );
+}
+END_TEST
+
+START_TEST(test_bitset_stream_size)
+{
+	struct bitset *map = bitset_alloc( 64, 1 );
+	bitset_enable_stream( map );
+	bitset_set_range( map, 0, 32 );
+	bitset_set_range( map, 16, 32 );
+	bitset_set_range( map, 7, 16 );
+
+	bitset_clear_range( map, 0, 32 );
+	bitset_clear_range( map, 16, 32 );
+	bitset_clear_range( map, 48, 16 );
+	bitset_disable_stream( map );
+
+	ck_assert_int_eq( 8, bitset_stream_size( map ) );
+
+	bitset_free( map );
+}
+END_TEST
+
+START_TEST(test_bitset_stream_queued_bytes)
+{
+	struct bitset *map = bitset_alloc( 64, 1 );
+	bitset_enable_stream( map );
+	bitset_set_range( map, 0, 32 );
+	bitset_set_range( map, 16, 32 );
+	bitset_set_range( map, 7, 16 );
+
+	bitset_clear_range( map, 0, 32 );
+	bitset_clear_range( map, 16, 32 );
+	bitset_clear_range( map, 48, 16 );
+	bitset_clear_range( map, 0, 2 );
+	bitset_disable_stream( map );
+
+	ck_assert_int_eq( 64, bitset_stream_queued_bytes( map, BITSET_STREAM_ON ) );
+	ck_assert_int_eq( 80, bitset_stream_queued_bytes( map, BITSET_STREAM_SET ) );
+	ck_assert_int_eq( 82, bitset_stream_queued_bytes( map, BITSET_STREAM_UNSET ) );
+	ck_assert_int_eq( 64, bitset_stream_queued_bytes( map, BITSET_STREAM_OFF ) );
+	bitset_free( map );
+}
+END_TEST
 
 Suite* bitset_suite(void)
 {
 	Suite *s = suite_create("bitset");
+
 	TCase *tc_bit = tcase_create("bit");
-	TCase *tc_bitset = tcase_create("bitset");
 	tcase_add_test(tc_bit, test_bit_set);
 	tcase_add_test(tc_bit, test_bit_clear);
 	tcase_add_test(tc_bit, test_bit_tests);
 	tcase_add_test(tc_bit, test_bit_ranges);
 	tcase_add_test(tc_bit, test_bit_runs);
+	suite_add_tcase(s, tc_bit);
+
+	TCase *tc_bitset = tcase_create("bitset");
 	tcase_add_test(tc_bitset, test_bitset);
 	tcase_add_test(tc_bitset, test_bitset_set);
 	tcase_add_test(tc_bitset, test_bitset_clear);
-	suite_add_tcase(s, tc_bit);
+	tcase_add_test(tc_bitset, test_bitset_run_count);
+	tcase_add_test(tc_bitset, test_bitset_set_range);
+	tcase_add_test(tc_bitset, test_bitset_clear_range);
+	tcase_add_test(tc_bitset, test_bitset_set_range_doesnt_push_to_stream);
+	tcase_add_test(tc_bitset, test_bitset_clear_range_doesnt_push_to_stream);
 	suite_add_tcase(s, tc_bitset);
-	
+
+
+	TCase *tc_bitset_stream = tcase_create("bitset_stream");
+	tcase_add_test(tc_bitset_stream, test_bitset_enable_stream);
+	tcase_add_test(tc_bitset_stream, test_bitset_disable_stream);
+	tcase_add_test(tc_bitset_stream, test_bitset_stream_with_set_range);
+	tcase_add_test(tc_bitset_stream, test_bitset_stream_with_clear_range);
+	tcase_add_test(tc_bitset_stream, test_bitset_stream_size);
+	tcase_add_test(tc_bitset_stream, test_bitset_stream_queued_bytes);
+	suite_add_tcase(s, tc_bitset_stream);
+
 	return s;
 }
 

tests/unit/check_client.c

@@ -76,8 +76,8 @@ START_TEST( test_read_request_quits_on_stop_signal )
 	
 	client_signal_stop( c );
 
-	int client_read_request( struct client *, struct nbd_request *);
-	fail_unless( 0 == client_read_request( c, &nbdr ), "Didn't quit on stop." );
+	int client_serve_request( struct client *);
+	fail_unless( 1 == client_serve_request( c ), "Didn't quit on stop." );
 
 	close( fds[0] );
 	close( fds[1] );

tests/unit/check_flexnbd.c

@@ -7,15 +7,12 @@ START_TEST( test_listening_assigns_sock )
 {
 	struct flexnbd * flexnbd = flexnbd_create_listening(
 			"127.0.0.1",
-			NULL,
 			"4777",
-			NULL,
 			"fakefile",
 			"fakesock",
 			0,
 			0,
-			NULL,
-			1 );
+			NULL );
 	fail_if( NULL == flexnbd->control->socket_name, "No socket was copied" );
 }
 END_TEST

tests/unit/check_listen.c

@@ -1,57 +0,0 @@
-#include "serve.h"
-#include "listen.h"
-#include "util.h"
-#include "flexnbd.h"
-
-#include <check.h>
-#include <string.h>
-
-START_TEST( test_defaults_main_serve_opts )
-{
-	struct flexnbd flexnbd;
-	struct listen * listen = listen_create( &flexnbd, "127.0.0.1", NULL, "4777", NULL,
-			"foo", 0, 0, NULL, 1 );
-	NULLCHECK( listen );
-	struct server *init_serve = listen->init_serve;
-	struct server *main_serve = listen->main_serve;
-	NULLCHECK( init_serve );
-	NULLCHECK( main_serve );
-
-	fail_unless( 0 == memcmp(&init_serve->bind_to,
-				&main_serve->bind_to,
-				sizeof( union mysockaddr )),
-			"Main serve bind_to was not set" );
-}
-END_TEST
-
-
-Suite* listen_suite(void)
-{
-	Suite *s = suite_create("listen");
-	TCase *tc_create = tcase_create("create");
-
-	tcase_add_exit_test(tc_create, test_defaults_main_serve_opts, 0);
-
-	suite_add_tcase(s, tc_create);
-
-	return s;
-}
-
-#ifdef DEBUG
-# define LOG_LEVEL 0
-#else
-# define LOG_LEVEL 2
-#endif
-
-int main(void)
-{
-	log_level = LOG_LEVEL;
-	int number_failed;
-	Suite *s = listen_suite();
-	SRunner *sr = srunner_create(s);
-	srunner_run_all(sr, CK_NORMAL);
-	number_failed = srunner_ntests_failed(sr);
-	srunner_free(sr);
-	return (number_failed == 0) ? 0 : 1;
-}
-

tests/unit/check_mbox.c

@@ -66,9 +66,9 @@ START_TEST( test_receive_blocks_until_post )
 END_TEST
 
 
-Suite* acl_suite(void)
+Suite* mbox_suite(void)
 {
-	Suite *s = suite_create("acl");
+	Suite *s = suite_create("mbox");
 	TCase *tc_create = tcase_create("create");
 	TCase *tc_post = tcase_create("post");
 
@@ -93,7 +93,7 @@ int main(void)
 	log_level = 2;
 #endif
 	int number_failed;
-	Suite *s = acl_suite();
+	Suite *s = mbox_suite();
 	SRunner *sr = srunner_create(s);
 	srunner_run_all(sr, CK_NORMAL);
 	log_level = 0;

tests/unit/check_nbdtypes.c

@@ -88,14 +88,14 @@ START_TEST(test_request_handle)
 	struct nbd_request_raw request_raw;
 	struct nbd_request     request;
 
-	memcpy( request_raw.handle, "MYHANDLE", 8 );
+	memcpy( request_raw.handle.b, "MYHANDLE", 8 );
 	
 	nbd_r2h_request( &request_raw, &request );
-	memset( request_raw.handle, 0, 8 );
+	request_raw.handle.w = 0;
 	nbd_h2r_request( &request, &request_raw );
   
-	fail_unless( memcmp( request.handle, "MYHANDLE", 8 ) == 0, "The handle was not copied." );
-	fail_unless( memcmp( request_raw.handle, "MYHANDLE", 8 ) == 0, "The handle was not copied back." );
+	fail_unless( memcmp( request.handle.b, "MYHANDLE", 8 ) == 0, "The handle was not copied." );
+	fail_unless( memcmp( request_raw.handle.b, "MYHANDLE", 8 ) == 0, "The handle was not copied back." );
 }
 END_TEST
 
@@ -170,14 +170,14 @@ START_TEST(test_reply_handle)
 	struct nbd_reply_raw reply_raw;
 	struct nbd_reply     reply;
 
-	memcpy( reply_raw.handle, "MYHANDLE", 8 );
+	memcpy( reply_raw.handle.b, "MYHANDLE", 8 );
 	
 	nbd_r2h_reply( &reply_raw, &reply );
-	memset( reply_raw.handle, 0, 8 );
+	reply_raw.handle.w = 0;
 	nbd_h2r_reply( &reply, &reply_raw );
   
-	fail_unless( memcmp( reply.handle, "MYHANDLE", 8 ) == 0, "The handle was not copied." );
-	fail_unless( memcmp( reply_raw.handle, "MYHANDLE", 8 ) == 0, "The handle was not copied back." );
+	fail_unless( memcmp( reply.handle.b, "MYHANDLE", 8 ) == 0, "The handle was not copied." );
+	fail_unless( memcmp( reply_raw.handle.b, "MYHANDLE", 8 ) == 0, "The handle was not copied back." );
 }
 END_TEST
 
@@ -188,14 +188,15 @@ START_TEST( test_convert_from )
 	 * nbd_request_raw */
 	struct nbd_request_raw request_raw;
 	struct nbd_request     request;
-	char readbuf[] = {0x80, 0, 0, 0, 0, 0, 0, 0};
 
-	memcpy( &request_raw.from, readbuf, 8 );
+	uint64_t target = 0x8000000000000000;
 
+	/* this is stored big-endian */
+	request_raw.from = htobe64(target);
+
+	/* We expect this to convert big-endian to the host format */
 	nbd_r2h_request( &request_raw, &request );
 
-	uint64_t target = 1;
-	target <<= 63;
 	fail_unless( target == request.from, "from was wrong" );
 }	
 END_TEST

tests/unit/check_readwrite.c

@@ -9,6 +9,9 @@
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 
@@ -19,7 +22,7 @@
 
 
 int fd_read_request( int, struct nbd_request_raw *);
-int fd_write_reply( int, char *, int );
+int fd_write_reply( int, uint64_t, int );
 
 int marker;
 
@@ -43,8 +46,7 @@ void * responder( void *respond_uncast )
 	struct respond * resp = (struct respond *) respond_uncast;
 	int sock_fd = resp->sock_fds[1];
 	struct nbd_request_raw request_raw;
-	char wrong_handle[] = "WHOOPSIE";
-
+	uint64_t wrong_handle = 0x80;
 
 	if( fd_read_request( sock_fd, &request_raw ) == -1){
 		fprintf(stderr, "Problem with fd_read_request\n");
@@ -54,8 +56,9 @@ void * responder( void *respond_uncast )
 			fd_write_reply( sock_fd, wrong_handle, 0 );
 		}
 		else {
-			fd_write_reply( sock_fd, resp->received.handle, 0 );
+			fd_write_reply( sock_fd, resp->received.handle.w, 0 );
 		}
+		write( sock_fd, "12345678", 8 );
 	}
 	return NULL;
 }
@@ -85,14 +88,16 @@ void respond_destroy( struct respond * respond ){
 }
 
 
-void * entruster( void * nothing __attribute__((unused)))
+void * reader( void * nothing __attribute__((unused)))
 {
 	DECLARE_ERROR_CONTEXT( error_context );
 	error_set_handler( (cleanup_handler *)error_marker, error_context );
 
 	struct respond * respond = respond_create( 1 );
+	int devnull = open("/dev/null", O_WRONLY);
+	char outbuf[8] = {0};
 
-	socket_nbd_entrust( respond->sock_fds[0] );
+	socket_nbd_read( respond->sock_fds[0], 0, 8, devnull, outbuf, 1 );
 
 	return NULL;
 }
@@ -101,13 +106,14 @@ START_TEST( test_rejects_mismatched_handle )
 {
 
 	error_init();
-	pthread_t entruster_thread;
+	pthread_t reader_thread;
 
 	log_level=5;
 	
 	marker = 0;
-	pthread_create( &entruster_thread, NULL, entruster, NULL );
-	FATAL_UNLESS( 0 == pthread_join( entruster_thread, NULL ), "pthread_join failed");
+	pthread_create( &reader_thread, NULL, reader, NULL );
+	FATAL_UNLESS( 0 == pthread_join( reader_thread, NULL ),
+			"pthread_join failed");
 	
 	log_level=2;
 
@@ -120,19 +126,10 @@ START_TEST( test_accepts_matched_handle )
 {
 	struct respond * respond = respond_create( 0 );
 
-	socket_nbd_entrust( respond->sock_fds[0] );
+	int devnull = open("/dev/null", O_WRONLY);
+	char outbuf[8] = {0};
 
-	respond_destroy( respond );
-}
-END_TEST
-
-
-START_TEST( test_entrust_type_sent )
-{
-	struct respond * respond = respond_create( 0 );
-
-	socket_nbd_entrust( respond->sock_fds[0] );
-	fail_unless( respond->received.type == REQUEST_ENTRUST, "Wrong type sent." );
+	socket_nbd_read( respond->sock_fds[0], 0, 8, devnull, outbuf, 1 );
 
 	respond_destroy( respond );
 }
@@ -152,14 +149,13 @@ END_TEST
 
 Suite* readwrite_suite(void)
 {
-	Suite *s = suite_create("acl");
+	Suite *s = suite_create("readwrite");
 	TCase *tc_transfer = tcase_create("entrust");
 	TCase *tc_disconnect = tcase_create("disconnect");
 
 
 	tcase_add_test(tc_transfer, test_rejects_mismatched_handle);
 	tcase_add_exit_test(tc_transfer, test_accepts_matched_handle, 0);
-	tcase_add_test( tc_transfer, test_entrust_type_sent );
 
 	/* This test is a little funny.  We respond with a dodgy handle
 	 * and check that this *doesn't* cause a message rejection,

tests/unit/check_serve.c

@@ -64,7 +64,7 @@ START_TEST( test_replaces_acl )
 {
 	struct flexnbd flexnbd;
 	flexnbd.signal_fd = -1;
-	struct server * s = server_create( &flexnbd, "127.0.0.1", "0", dummy_file, 0, 0, NULL, 1, 1 );
+	struct server * s = server_create( &flexnbd, "127.0.0.1", "0", dummy_file, 0, 0, NULL, 1, 0, 1 );
 	struct acl * new_acl = acl_create( 0, NULL, 0 );
 
 	server_replace_acl( s, new_acl );
@@ -79,7 +79,7 @@ START_TEST( test_signals_acl_updated )
 {
 	struct flexnbd flexnbd;
 	flexnbd.signal_fd = -1;
-	struct server * s = server_create( &flexnbd, "127.0.0.1", "0", dummy_file, 0, 0, NULL, 1, 1 );
+	struct server * s = server_create( &flexnbd, "127.0.0.1", "0", dummy_file, 0, 0, NULL, 1, 0, 1 );
 	struct acl * new_acl = acl_create( 0, NULL, 0 );
 
 	server_replace_acl( s, new_acl );
@@ -93,7 +93,7 @@ END_TEST
 
 int connect_client( char *addr, int actual_port, char *source_addr )
 {
-	int client_fd;
+	int client_fd = -1;
 
 	struct addrinfo hint;
 	struct addrinfo *ailist, *aip;
@@ -148,7 +148,7 @@ START_TEST( test_acl_update_closes_bad_client )
 	 */
 	struct flexnbd flexnbd;
 	flexnbd.signal_fd = -1;
-	struct server * s = server_create( &flexnbd, "127.0.0.7", "0", dummy_file, 0, 0, NULL, 1, 1 );
+	struct server * s = server_create( &flexnbd, "127.0.0.7", "0", dummy_file, 0, 0, NULL, 1, 0, 1 );
 	struct acl * new_acl = acl_create( 0, NULL, 1 );
 	struct client * c;
 	struct client_tbl_entry * entry;
@@ -193,7 +193,7 @@ START_TEST( test_acl_update_leaves_good_client )
 	struct flexnbd flexnbd;
 	flexnbd.signal_fd = -1;
 
-	struct server * s = server_create( &flexnbd, "127.0.0.7", "0", dummy_file, 0, 0, NULL, 1, 1 );
+	struct server * s = server_create( &flexnbd, "127.0.0.7", "0", dummy_file, 0, 0, NULL, 1, 0, 1 );
 
 	char *lines[] = {"127.0.0.1"};
 	struct acl * new_acl = acl_create( 1, lines, 1 );
@@ -241,7 +241,7 @@ Suite* serve_suite(void)
 	tcase_add_test(tc_acl_update, test_replaces_acl);
 	tcase_add_test(tc_acl_update, test_signals_acl_updated);
 
-	tcase_add_exit_test(tc_acl_update, test_acl_update_closes_bad_client, 0);  
+	tcase_add_exit_test(tc_acl_update, test_acl_update_closes_bad_client, 0);
 	tcase_add_exit_test(tc_acl_update, test_acl_update_leaves_good_client, 0);
 
 	suite_add_tcase(s, tc_acl_update);

tests/unit/check_sockutil.c

@@ -0,0 +1,115 @@
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <netinet/tcp.h>
+
+#include "sockutil.h"
+
+#include <check.h>
+
+START_TEST( test_sockaddr_address_string_af_inet_converts_to_string )
+{
+	struct sockaddr sa;
+	struct sockaddr_in* v4 = (struct sockaddr_in*) &sa;
+	char testbuf[128];
+	const char* result;
+
+	v4->sin_family = AF_INET;
+	v4->sin_port = htons( 4777 );
+	ck_assert_int_eq( 1, inet_pton( AF_INET, "192.168.0.1", &v4->sin_addr ));
+
+	result = sockaddr_address_string( &sa, &testbuf[0], 128 );
+	ck_assert( result != NULL );
+
+	ck_assert_str_eq( "192.168.0.1 port 4777", testbuf );
+}
+END_TEST
+
+
+START_TEST( test_sockaddr_address_string_af_inet6_converts_to_string )
+{
+	struct sockaddr_in6 v6_raw;
+	struct sockaddr_in6* v6 = &v6_raw;
+	struct sockaddr* sa = (struct sockaddr*) &v6_raw;
+
+	char testbuf[128];
+	const char* result;
+
+	v6->sin6_family = AF_INET6;
+	v6->sin6_port = htons( 4777 );
+	ck_assert_int_eq( 1, inet_pton( AF_INET6, "fe80::1", &v6->sin6_addr ));
+
+	result = sockaddr_address_string( sa, &testbuf[0], 128 );
+	ck_assert( result != NULL );
+
+	ck_assert_str_eq( "fe80::1 port 4777", testbuf );
+}
+END_TEST
+
+/* We don't know what it is, so we just call it "???" and return NULL */
+START_TEST( test_sockaddr_address_string_af_unspec_is_failure )
+{
+	struct sockaddr sa;
+	struct sockaddr_in* v4 = (struct sockaddr_in*) &sa;
+	char testbuf[128];
+	const char* result;
+
+	v4->sin_family = AF_UNSPEC;
+	v4->sin_port = htons( 4777 );
+	ck_assert_int_eq( 1, inet_pton( AF_INET, "192.168.0.1", &v4->sin_addr ));
+
+	result = sockaddr_address_string( &sa, &testbuf[0], 128 );
+	ck_assert( result == NULL );
+
+	ck_assert_str_eq( "???", testbuf );
+}
+END_TEST
+
+/* This is a complete failure to parse, rather than a partial failure */
+START_TEST( test_sockaddr_address_string_doesnt_overflow_short_buffer )
+{
+	struct sockaddr sa;
+	struct sockaddr_in* v4 = (struct sockaddr_in*) &sa;
+	char testbuf[128];
+	const char* result;
+
+	memset( testbuf, 0, 128 );
+	v4->sin_family = AF_INET;
+	v4->sin_port = htons( 4777 );
+	ck_assert_int_eq( 1, inet_pton( AF_INET, "192.168.0.1", &v4->sin_addr ));
+	memset( &testbuf, 0, 128 );
+
+	result = sockaddr_address_string( &sa, &testbuf[0], 2 );
+	ck_assert( result == NULL );
+
+	ck_assert_str_eq( "??", testbuf );
+
+}
+END_TEST
+
+Suite *sockutil_suite(void)
+{
+	Suite *s = suite_create("sockutil");
+
+	TCase *tc_sockaddr_address_string = tcase_create("sockaddr_address_string");
+
+	tcase_add_test(tc_sockaddr_address_string, test_sockaddr_address_string_af_inet_converts_to_string);
+	tcase_add_test(tc_sockaddr_address_string, test_sockaddr_address_string_af_inet6_converts_to_string);
+    tcase_add_test(tc_sockaddr_address_string, test_sockaddr_address_string_af_unspec_is_failure);
+	tcase_add_test(tc_sockaddr_address_string, test_sockaddr_address_string_doesnt_overflow_short_buffer);
+	suite_add_tcase(s, tc_sockaddr_address_string);
+
+	return s;
+}
+
+int main(void)
+{
+	int number_failed;
+
+	Suite *s = sockutil_suite();
+	SRunner *sr = srunner_create(s);
+	srunner_run_all(sr, CK_NORMAL);
+	number_failed = srunner_ntests_failed(sr);
+	srunner_free(sr);
+	return (number_failed == 0) ? 0 : 1;
+}
+