Add stop signals to client threads

Rakefile

@@ -61,8 +61,24 @@ rule 'build/flexnbd' => OBJECTS do |t|
   gcc_link(t.name, t.sources)
 end
 
-TEST_MODULES.each do |m|
+
-  deps = ["tests/check_#{m}.c", "build/util.o"]
+file "build/tests/check_client" => 
+%w{tests/check_client.c
+  build/self_pipe.o
+  build/nbdtypes.o
+  build/control.o
+  build/readwrite.o
+  build/parse.o
+  build/client.o
+  build/serve.o 
+  build/ioutil.o 
+  build/util.o} do |t|
+  gcc_link t.name, t.prerequisites + [LIBCHECK]
+end
+
+
+(TEST_MODULES-["client"]).each do |m|
+  deps = ["tests/check_#{m}.c", "build/ioutil.o", "build/util.o"]
   maybe_obj_name = "build/#{m}.o"
 
   deps << maybe_obj_name if OBJECTS.include?( maybe_obj_name )

src/client.c

@@ -12,6 +12,39 @@
 #include <stdlib.h>
 
 
+struct client *client_create( struct server *serve, int socket )
+{
+	NULLCHECK( serve );
+
+	struct client *c;
+
+	c = xmalloc( sizeof( struct server ) );
+	c->socket = socket;
+	c->serve = serve;
+
+	c->stop_signal = self_pipe_create();
+
+	return c;
+}
+
+
+void client_signal_stop( struct client *client )
+{
+	NULLCHECK( client );
+
+	self_pipe_signal( client->stop_signal );
+}
+
+void client_destroy( struct client *client )
+{
+	NULLCHECK( client );
+
+	self_pipe_destroy( client->stop_signal );
+	free( 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
@@ -26,6 +59,8 @@
  */
 void write_not_zeroes(struct client* client, off64_t from, int len)
 {
+	NULLCHECK( client );
+
 	char *map = client->serve->block_allocation_map;
 
 	while (len > 0) {
@@ -349,10 +384,8 @@ void* client_serve(void* client_uncast)
 		client->socket
 	);
 
-	close(client->socket);
 	close(client->fileno);
 	munmap(client->mapped, client->serve->size);
-	free(client);
 	
 	return NULL;
 }

src/client.h

@@ -7,10 +7,15 @@ struct client {
 	int     fileno;
 	char*   mapped;
 
+	struct self_pipe * stop_signal;
+	
 	struct server* serve; /* FIXME: remove above duplication */
 };
 
 
 void* client_serve(void* client_uncast);
+struct client * client_create( struct server * serve, int socket );
+void client_destroy( struct client * client );
+void client_signal_stop( struct client * client );
 
 #endif

src/flexnbd.c

@@ -190,11 +190,12 @@ void read_serve_param( int c, char **ip_addr, char **ip_port, char **file, char
 		case 's':
 			*sock = optarg;
 			break;
-		case 'v':
-			set_debug(1);
 		case 'd':
 			*default_deny = 1;
 			break;
+		case 'v':
+			set_debug(1);
+			break;
 		default:
 			exit_err( serve_help_text );
 			break;

src/ioutil.c

@@ -235,3 +235,11 @@ int read_lines_until_blankline(int fd, int max_line_length, char ***lines)
 	}
 }
 
+
+int fd_is_closed( int fd_in )
+{
+	int errno_old = errno;
+	int result = fcntl( fd_in, F_GETFD, 9 ) < 0;
+	errno = errno_old;
+	return result;
+}

src/ioutil.h

@@ -54,5 +54,10 @@ int read_lines_until_blankline(int fd, int max_line_length, char ***lines);
   */
 int open_and_mmap(char* filename, int* out_fd, off64_t *out_size, void **out_map);
 
+
+/** Check to see whether the given file descriptor is closed.
+ */
+int fd_is_closed( int fd_in );
+
 #endif
 

src/self_pipe.c

@@ -100,21 +100,25 @@ int self_pipe_signal( struct self_pipe * sig )
 /** 
  * Clear a received signal from the pipe.  Every signal sent must be
  * cleared by one (and only one) recipient when they return from select().
+ * Returns the number of bytes read, which will be 1 on success and 0 if
+ * there was no signal.
  */
 int self_pipe_signal_clear( struct self_pipe *sig )
 {
 	char buf[1];
 
-	read( sig->read_fd, buf, 1 );
+	return read( sig->read_fd, buf, 1 );
-	return 1;
 }
 
+
 /**
  * Close the pipe and free the self_pipe.  Do not try to use the
  * self_pipe struct after calling this, the innards are mush.
  */
 int self_pipe_destroy( struct self_pipe * sig )
 {
+	NULLCHECK(sig);
+
 	while( close( sig->read_fd  ) == -1 && errno == EINTR );
 	while( close( sig->write_fd ) == -1 && errno == EINTR );
 

src/serve.c

@@ -22,6 +22,8 @@
 
 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;
 	
@@ -34,12 +36,16 @@ static inline void* sockaddr_address_data(struct sockaddr* sockaddr)
 
 void server_dirty(struct server *serve, off64_t from, int len)
 {
+	NULLCHECK( serve );
+
 	if (serve->mirror)
 		bitset_set_range(serve->mirror->dirty_map, from, len);
 }
 
 int server_lock_io( struct server * serve)
 {
+	NULLCHECK( serve );
+
 	SERVER_ERROR_ON_FAILURE(
 		pthread_mutex_lock(&serve->l_io),
 		"Problem with I/O lock"
@@ -51,6 +57,8 @@ int server_lock_io( struct server * serve)
 
 void server_unlock_io( struct server* serve )
 {
+	NULLCHECK( serve );
+
 	SERVER_ERROR_ON_FAILURE(
 		pthread_mutex_unlock(&serve->l_io),
 		"Problem with I/O unlock"
@@ -64,6 +72,8 @@ static int testmasks[9] = { 0,128,192,224,240,248,252,254,255 };
   */
 int is_included_in_acl(int list_length, struct ip_and_mask (*list)[], union mysockaddr* test)
 {
+	NULLCHECK( test );
+
 	int i;
 	
 	for (i=0; i < list_length; i++) {
@@ -117,6 +127,8 @@ int is_included_in_acl(int list_length, struct ip_and_mask (*list)[], union myso
 /** 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 ? 
@@ -147,46 +159,130 @@ void serve_open_server_socket(struct server* params)
 	);
 }
 
+/**
+ * Check to see if a client thread has finished, and if so, tidy up
+ * after it.
+ * Returns 1 if the thread was cleaned up and the slot freed, 0
+ * otherwise.
+ *
+ * It's important that client_destroy gets called in the same thread
+ * which signals the client threads to stop.  This avoids the
+ * possibility of sending a stop signal via a signal which has already
+ * been destroyed.  However, it means that stopped client threads,
+ * including their signal pipes, won't be cleaned up until the next new
+ * client connection attempt.
+ */
+int cleanup_client_thread( struct client_tbl_entry * entry )
+{
+	NULLCHECK( entry );
+
+	int was_closed = 0;
+	void * status;
+
+	if (entry->thread != 0) {
+		char s_client_address[64];
+
+		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 );
+
+		if (pthread_tryjoin_np(entry->thread, &status) < 0) {
+			if (errno != EBUSY)
+				SERVER_ERROR_ON_FAILURE(-1, "Problem with joining thread");
+		}
+		else {
+			debug("nbd thread %p exited (%s) with status %ld", 
+					(int) entry->thread, 
+					s_client_address, 
+					(uint64_t)status);
+			client_destroy( entry->client );
+			entry->thread = 0;
+			was_closed  = 1;
+		}
+	}
+
+	return was_closed;
+}
+
+
 /** We can only accommodate MAX_NBD_CLIENTS connections at once.  This function
  *  goes through the current list, waits for any threads that have finished
  *  and returns the next slot free (or -1 if there are none).
  */
 int cleanup_and_find_client_slot(struct server* params)
 {
-	int slot=-1, i;
+	NULLCHECK( params );
 
-	for (i=0; i < MAX_NBD_CLIENTS; i++) {
+	int slot=-1, i,j;
-		void* status;
 
-		if (params->nbd_client[i].thread != 0) {
+	for ( i = 0; i < MAX_NBD_CLIENTS; i++ ) {
-			char s_client_address[64];
+		cleanup_client_thread( &params->nbd_client[i] );
-			
-			memset(s_client_address, 0, 64);
-			strcpy(s_client_address, "???");
-			inet_ntop(
-				params->nbd_client[i].address.generic.sa_family, 
-				sockaddr_address_data(&params->nbd_client[i].address.generic), 
-                                    s_client_address, 
-				64
-			);
-			
-			if (pthread_tryjoin_np(params->nbd_client[i].thread, &status) < 0) {
-				if (errno != EBUSY)
-					SERVER_ERROR_ON_FAILURE(-1, "Problem with joining thread");
 	}
-			else {
+
-				params->nbd_client[i].thread = 0;
+	for ( j = 0; j < MAX_NBD_CLIENTS; j++ ) {
-				debug("nbd thread %d exited (%s) with status %ld", (int) params->nbd_client[i].thread, s_client_address, (uint64_t)status);
+		if( params->nbd_client[j].thread == 0 && slot == -1 ){
+			slot = j;
+			break;
 		}
 	}
 	
-		if (params->nbd_client[i].thread == 0 && slot == -1)
+	if ( -1 == slot ) { debug( "No client slot found." ); }
-			slot = i;
-	}
 
 	return slot;
 }
 
+
+int server_acl_accepts( struct server *params, union mysockaddr * client_address )
+{
+	NULLCHECK( params );
+	NULLCHECK( client_address );
+
+	if (params->acl) {
+		if (is_included_in_acl(params->acl_entries, params->acl, client_address))
+			return 1;
+	} else {
+		if (!params->default_deny)
+			return 1;
+	}
+	return 0;
+}
+
+
+int server_should_accept_client( 
+		struct server * params, 
+		int client_fd, 
+		union mysockaddr * client_address,
+		char *s_client_address,
+		size_t s_client_address_len )
+{
+	NULLCHECK( params );
+	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) {
+		debug( "Rejecting client %s: Bad client_address", s_client_address );
+		write(client_fd, "Bad client_address", 18);
+		return 0;
+	}
+
+	if ( !server_acl_accepts( params, client_address ) ) {
+		debug( "Rejecting client %s: Access control error", s_client_address );
+		debug( "We %s have an acl, and default_deny is %s", 
+				(params->acl ? "do" : "do not"),
+				(params->default_deny ? "true" : "false") );
+ 		write(client_fd, "Access control error", 20);
+ 		return 0;
+	}
+
+	return 1;
+}
+
+
 /** Dispatch function for accepting an NBD connection and starting a thread
   * to handle it.  Rejects the connection if there is an ACL, and the far end's
   * address doesn't match, or if there are too many clients already connected.
@@ -196,49 +292,33 @@ void accept_nbd_client(
 		int client_fd, 
 		union mysockaddr* client_address)
 {
+	NULLCHECK(params);
+	NULLCHECK(client_address);
+
 	struct client* client_params;
 	int slot = cleanup_and_find_client_slot(params); 
-	char s_client_address[64];
+	char s_client_address[64] = {0};
-	int acl_passed = 0;
 
 
-	if (inet_ntop(client_address->generic.sa_family,
+	if ( !server_should_accept_client( params, client_fd, client_address, s_client_address, 64 ) ) {
-				sockaddr_address_data(&client_address->generic),
+		close( client_fd );
-				s_client_address, 64) == NULL) {
-		write(client_fd, "Bad client_address", 18);
-		close(client_fd);
 		return;
 	}
 
-
-	if (params->acl) {
-		if (is_included_in_acl(params->acl_entries, params->acl, client_address))
-			acl_passed = 1;
-	} else {
-		if (!params->default_deny)
-			acl_passed = 1;
-	}
-
-	if (!acl_passed) {
- 		write(client_fd, "Access control error", 20);
- 		close(client_fd);
- 		return;
-	}
-
-	
 	if (slot < 0) {
 		write(client_fd, "Too many clients", 16);
 		close(client_fd);
 		return;
 	}
 	
-	client_params = xmalloc(sizeof(struct client));
+	debug( "Client %s accepted.", s_client_address );
-	client_params->socket = client_fd;
+	client_params = client_create( params, client_fd );
-	client_params->serve = params;
+	params->nbd_client[slot].client = client_params;
 	
 	if (pthread_create(&params->nbd_client[slot].thread, NULL, client_serve, client_params) < 0) {
+		debug( "Thread creation problem." );
 		write(client_fd, "Thread creation problem", 23);
-		free(client_params);
+		client_destroy( client_params );
 		close(client_fd);
 		return;
 	}
@@ -252,16 +332,15 @@ void accept_nbd_client(
 
 int server_is_closed(struct server* serve)
 {
-	int errno_old = errno;
+	NULLCHECK( serve );
-	int result = fcntl(serve->server_fd, F_GETFD, 0) < 0;
+	return fd_is_closed( serve->server_fd );
-	errno = errno_old;
-	return result;
 }
 
 
 /** Accept either an NBD or control socket connection, dispatch appropriately */
 void serve_accept_loop(struct server* params) 
 {
+	NULLCHECK( params );
 	while (1) {
 		int              activity_fd, client_fd;
 		union mysockaddr client_address;
@@ -285,10 +364,14 @@ void serve_accept_loop(struct server* params)
 		client_fd = accept(activity_fd, &client_address.generic, &socklen);
 		
 		
-		if (activity_fd == params->server_fd)
+		if (activity_fd == params->server_fd) {
+			debug("Accepted nbd client");
 			accept_nbd_client(params, client_fd, &client_address);
-		if (activity_fd == params->control_fd)
+		}
+		if (activity_fd == params->control_fd) {
+			debug("Accepted control client"); 
 			accept_control_connection(params, client_fd, &client_address);
+		}
 			
 	}
 }
@@ -298,8 +381,11 @@ void serve_accept_loop(struct server* params)
   */
 void serve_init_allocation_map(struct server* params)
 {
+	NULLCHECK( params );
+
 	int fd = open(params->filename, O_RDONLY);
 	off64_t size;
+
 	SERVER_ERROR_ON_FAILURE(fd, "Couldn't open %s", params->filename);
 	size = lseek64(fd, 0, SEEK_END);
 	params->size = size;
@@ -314,6 +400,7 @@ void serve_init_allocation_map(struct server* params)
 /* Tell the server to close all the things. */
 void serve_signal_close( struct server * serve )
 {
+	NULLCHECK( serve );
 	self_pipe_signal( serve->close_signal );
 }
 
@@ -321,6 +408,8 @@ void serve_signal_close( struct server * serve )
 /** Closes sockets, frees memory and waits for all client threads to finish */
 void serve_cleanup(struct server* params)
 {
+	NULLCHECK( params );
+
 	int i;
 	
 	close(params->server_fd);
@@ -354,6 +443,8 @@ void serve_cleanup(struct server* params)
 /** Full lifecycle of the server */
 void do_serve(struct server* params)
 {
+	NULLCHECK( params );
+
 	pthread_mutex_init(&params->l_io, NULL);
 
 	params->close_signal = self_pipe_create();

src/serve.h

@@ -35,6 +35,13 @@ struct control_params {
 	struct server* serve;
 };
 
+struct client_tbl_entry {
+	pthread_t thread;
+	union mysockaddr address;
+	struct client * client;
+};
+
+
 #define MAX_NBD_CLIENTS 16
 struct server {
 	/** address/port to bind to */
@@ -71,8 +78,7 @@ struct server {
 	
 	char*                block_allocation_map;
 	
-	struct { pthread_t thread; union mysockaddr address; }
+	struct client_tbl_entry nbd_client[MAX_NBD_CLIENTS];
-	                     nbd_client[MAX_NBD_CLIENTS];
 };
 
 int server_is_closed(struct server* serve);

src/util.c

@@ -71,12 +71,15 @@ void set_debug(int value) {
 
 void debug(const char *msg, ...) {
 	va_list argp;
+	va_start( argp, msg );
 
 	if ( global_debug ) {
 		fprintf(stderr, "%08x %4d: ", (int) pthread_self(), (int) clock() );
-    fprintf(stderr, msg, argp);
+		vfprintf(stderr, msg, argp);
 		fprintf(stderr, "\n");
 	}
+
+	va_end( argp );
 }
 #endif
 

src/util.h

@@ -30,5 +30,8 @@ void debug(const char*msg, ...);
 #define SERVER_ERROR_ON_FAILURE(test, msg, ...) \
   if (test < 0) { error(1, 0, NULL, msg, ##__VA_ARGS__); }
 
+
+#define NULLCHECK(x); if ( NULL == (x) ) { SERVER_ERROR( "Null " #x "." ); }
+
 #endif
 

tests/check_client.c

@@ -0,0 +1,95 @@
+#include <check.h>
+
+#include "self_pipe.h"
+
+#include "client.h"
+
+
+START_TEST( test_assigns_socket )
+{
+	struct client * c;
+
+	c = client_create( NULL, 42 );
+
+	fail_unless( 42 == c->socket, "Socket wasn't assigned." );
+}
+END_TEST
+
+
+START_TEST( test_assigns_server )
+{
+	struct client * c;
+	/* can't predict the storage size so we can't allocate one on
+	 * the stack
+	 */
+	struct server * s = (struct server *)42;
+
+	c = client_create( (struct server *)s, 0 );
+
+	fail_unless( s == c->serve, "Serve wasn't assigned." );
+
+}
+END_TEST
+
+
+START_TEST( test_opens_stop_signal )
+{
+	struct client *c = client_create( NULL, 0 );
+
+	client_signal_stop( c );
+
+	fail_unless( 1 == self_pipe_signal_clear( c->stop_signal ),
+			"No signal was sent." );
+
+}
+END_TEST
+
+
+START_TEST( test_closes_stop_signal )
+{
+	struct client *c = client_create( NULL, 0 );
+	int read_fd = c->stop_signal->read_fd;
+	int write_fd = c->stop_signal->write_fd;
+
+	client_destroy( c );
+
+	fail_unless( fd_is_closed( read_fd ), "Stop signal wasn't destroyed." );
+	fail_unless( fd_is_closed( write_fd ), "Stop signal wasn't destroyed." );
+}
+END_TEST
+
+
+Suite *client_suite()
+{
+	Suite *s = suite_create("client");
+
+	TCase *tc_create = tcase_create("create");
+	TCase *tc_signal = tcase_create("signal");
+	TCase *tc_destroy = tcase_create("destroy");
+
+	tcase_add_test(tc_create, test_assigns_socket);
+	tcase_add_test(tc_create, test_assigns_server);
+
+	tcase_add_test(tc_signal, test_opens_stop_signal);
+
+	tcase_add_test( tc_destroy, test_closes_stop_signal );
+
+	suite_add_tcase(s, tc_create);
+	suite_add_tcase(s, tc_signal);
+	suite_add_tcase(s, tc_destroy);
+
+	return s;
+}
+
+int main(void)
+{
+	int number_failed;
+	
+	Suite *s = client_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/flexnbd.rb

@@ -1,4 +1,7 @@
 require 'socket'
+require 'thread'
+
+Thread.abort_on_exception = true
 
 # Noddy test class to exercise FlexNBD from the outside for testing.
 #
@@ -7,27 +10,64 @@ class FlexNBD
 
   def initialize(bin, ip, port)
     @bin  = bin
-    @debug = `#{@bin} serve --help` =~ /--debug/ ? "--debug" : ""
+    @debug = `#{@bin} serve --help` =~ /--verbose/ ? "--verbose" : ""
     @valgrind = ENV['VALGRIND'] ? "valgrind " : ""
     @bin = "#{@valgrind}#{@bin}"
     raise "#{bin} not executable" unless File.executable?(bin)
     @ctrl = "/tmp/.flexnbd.ctrl.#{Time.now.to_i}.#{rand}"
     @ip = ip
     @port = port
+    @kill = false
   end
 
-  def serve(file, *acl)
+  def debug?
-    File.unlink(ctrl) if File.exists?(ctrl)
+    !@debug.empty?
-    cmd ="#{@bin} serve "\
+  end
+
+  def debug( msg )
+    $stderr.puts msg if debug?
+  end
+
+
+  def serve_cmd( file, acl )
+    "#{@bin} serve "\
       "--addr #{ip} "\
       "--port #{port} "\
       "--file #{file} "\
       "--sock #{ctrl} "\
       "#{@debug} "\
       "#{acl.join(' ')}"
-    @pid = fork do
-      exec(cmd)
   end
+
+
+  def read_cmd( offset, length )
+    "#{@bin} read "\
+      "--addr #{ip} "\
+      "--port #{port} "\
+      "--from #{offset} "\
+      "#{@debug} "\
+      "--size #{length}"
+  end
+
+
+  def write_cmd( offset, data )
+    "#{@bin} write "\
+      "--addr #{ip} "\
+      "--port #{port} "\
+      "--from #{offset} "\
+      "#{@debug} "\
+      "--size #{data.length}"
+  end
+
+
+  def serve(file, *acl)
+    File.unlink(ctrl) if File.exists?(ctrl)
+    cmd =serve_cmd( file, acl )
+    debug( cmd )
+
+    @pid = fork do exec(cmd) end
+    start_wait_thread( @pid )
+
     while !File.socket?(ctrl)
       pid, status = Process.wait2(@pid, Process::WNOHANG)
       raise "server did not start (#{cmd})" if pid
@@ -36,30 +76,37 @@ class FlexNBD
     at_exit { kill }
   end
 
+  def start_wait_thread( pid )
+    Thread.start do
+      Process.waitpid2( pid )
+      unless @kill
+        $stderr.puts "flexnbd quit"
+        fail "flexnbd quit early"
+      end
+    end
+  end
+
+
   def kill
+    @kill = true
     Process.kill("INT", @pid)
-    Process.wait(@pid)
   end
 
   def read(offset, length)
-    IO.popen("#{@bin} read "\
+    cmd = read_cmd( offset, length )
-             "--addr #{ip} "\
+    debug( cmd )
-             "--port #{port} "\
+
-             "--from #{offset} "\
+    IO.popen(cmd) do |fh|
-             "#{@debug} "\
-             "--size #{length}","r") do |fh|
       return fh.read
     end
     raise "read failed" unless $?.success?
   end
 
   def write(offset, data)
-    IO.popen("#{@bin} write "\
+    cmd = write_cmd( offset, data )
-             "--addr #{ip} "\
+    debug( cmd )
-             "--port #{port} "\
+    
-             "--from #{offset} "\
+    IO.popen(cmd, "w") do |fh|
-             "#{@debug} "\
-             "--size #{data.length}","w") do |fh|
       fh.write(data)
     end
     raise "write failed" unless $?.success?