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flexnbd read/write: Switch to a non-blocking connect() to allow us to time these out

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This commit is contained in:
nick
2013-02-14 16:24:10 +00:00
parent 58c4a9530b
commit 03bc12dd57
3 changed files with 145 additions and 29 deletions
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42
src/readwrite.c
View File

@@ -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>
@@ -18,14 +19,14 @@ 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 );
FATAL_IF_NEGATIVE( close( fd ), SHOW_ERRNO( "FIXME" ) );
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" ) );
FATAL_IF_NEGATIVE( close( fd ), SHOW_ERRNO( "FIXME" ) );
return -1;
}
@@ -88,7 +89,7 @@ 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");
@@ -108,14 +109,15 @@ 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" );
@@ -126,16 +128,16 @@ void socket_nbd_read(int fd, off64_t from, int len, int out_fd, void* out_buf, i
{
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 {
@@ -150,13 +152,13 @@ void socket_nbd_write(int fd, off64_t from, int len, int in_fd, void* in_buf, in
{
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 {
@@ -165,7 +167,7 @@ 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);
}
@@ -200,13 +202,13 @@ 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);
}
@@ -216,7 +218,7 @@ 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);
}

118
src/sockutil.c
View File

@@ -1,7 +1,14 @@
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netinet/tcp.h>
#include "sockutil.h"
#include "util.h"
size_t sockaddr_size(const struct sockaddr* sa)
size_t sockaddr_size( const struct sockaddr* sa )
{
size_t ret = 0;
@@ -17,7 +24,7 @@ size_t sockaddr_size(const struct sockaddr* sa)
return ret;
}
const char* sockaddr_address_string(const struct sockaddr* sa, char* dest, size_t len)
const char* sockaddr_address_string( const struct sockaddr* sa, char* dest, size_t len )
{
NULLCHECK( sa );
NULLCHECK( dest );
@@ -47,18 +54,35 @@ const char* sockaddr_address_string(const struct sockaddr* sa, char* dest, size_
return ret;
}
int sock_set_reuseaddr(int fd, int optval)
int sock_set_reuseaddr( int fd, int optval )
{
return setsockopt( fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval) );
}
/* Set the tcp_nodelay option */
int sock_set_tcp_nodelay(int fd, int optval)
int sock_set_tcp_nodelay( int fd, int optval )
{
return setsockopt( fd, IPPROTO_TCP, TCP_NODELAY, &optval, sizeof(optval) );
}
int sock_try_bind(int fd, const struct sockaddr* sa)
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];
@@ -102,3 +126,87 @@ int sock_try_bind(int fd, const struct sockaddr* sa)
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:
break; /* Try again */
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;
}

14
src/sockutil.h
View File

@@ -2,11 +2,9 @@
#define SOCKUTIL_H
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <arpa/inet.h>
#include <netinet/tcp.h>
#include <sys/select.h>
/* Returns the size of the sockaddr, or 0 on error */
size_t sockaddr_size(const struct sockaddr* sa);
@@ -25,8 +23,16 @@ int sock_set_tcp_nodelay(int fd, int optval);
/* TODO: Set the tcp_cork option */
// int sock_set_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 );
#endif