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qemu
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Merge NBD client/server, by Laurent Vivier. 

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4834 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
ths 2008-07-03 10:23:51 +00:00
parent f8d39c01c3
commit cd831bd787
4 changed files with 213 additions and 11 deletions
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74
nbd.c
View File

@ -25,6 +25,7 @@
#include <ctype.h>
#include <inttypes.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
@ -183,6 +184,65 @@ error:
return -1;
}
int unix_socket_incoming(const char *path)
{
int s;
struct sockaddr_un addr;
int serrno;
s = socket(PF_UNIX, SOCK_STREAM, 0);
if (s == -1) {
return -1;
}
memset(&addr, 0, sizeof(addr));
addr.sun_family = AF_UNIX;
pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
goto error;
}
if (listen(s, 128) == -1) {
goto error;
}
return s;
error:
serrno = errno;
close(s);
errno = serrno;
return -1;
}
int unix_socket_outgoing(const char *path)
{
int s;
struct sockaddr_un addr;
int serrno;
s = socket(PF_UNIX, SOCK_STREAM, 0);
if (s == -1) {
return -1;
}
memset(&addr, 0, sizeof(addr));
addr.sun_family = AF_UNIX;
pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
goto error;
}
return s;
error:
serrno = errno;
close(s);
errno = serrno;
return -1;
}
/* Basic flow
Server Client
@ -225,12 +285,10 @@ int nbd_negotiate(BlockDriverState *bs, int csock, off_t size)
return 0;
}
int nbd_receive_negotiate(int fd, int csock)
int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
{
char buf[8 + 8 + 8 + 128];
uint64_t magic;
off_t size;
size_t blocksize;
TRACE("Receiving negotation.");
@ -241,8 +299,8 @@ int nbd_receive_negotiate(int fd, int csock)
}
magic = be64_to_cpup((uint64_t*)(buf + 8));
size = be64_to_cpup((uint64_t*)(buf + 16));
blocksize = 1024;
*size = be64_to_cpup((uint64_t*)(buf + 16));
*blocksize = 1024;
TRACE("Magic is %c%c%c%c%c%c%c%c",
isprint(buf[0]) ? buf[0] : '.',
@ -254,7 +312,7 @@ int nbd_receive_negotiate(int fd, int csock)
isprint(buf[6]) ? buf[6] : '.',
isprint(buf[7]) ? buf[7] : '.');
TRACE("Magic is 0x%" PRIx64, magic);
TRACE("Size is %" PRIu64, size);
TRACE("Size is %" PRIu64, *size);
if (memcmp(buf, "NBDMAGIC", 8) != 0) {
LOG("Invalid magic received");
@ -269,7 +327,11 @@ int nbd_receive_negotiate(int fd, int csock)
errno = EINVAL;
return -1;
}
return 0;
}
int nbd_init(int fd, int csock, off_t size, size_t blocksize)
{
TRACE("Setting block size to %lu", (unsigned long)blocksize);
if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {

5
nbd.h
View File

@ -27,9 +27,12 @@
#include "block_int.h"
int tcp_socket_incoming(const char *address, uint16_t port);
int unix_socket_outgoing(const char *path);
int unix_socket_incoming(const char *path);
int nbd_negotiate(BlockDriverState *bs, int csock, off_t size);
int nbd_receive_negotiate(int fd, int csock);
int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize);
int nbd_init(int fd, int csock, off_t size, size_t blocksize);
int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly);
int nbd_client(int fd, int csock);
int nbd_disconnect(int fd);

139
qemu-nbd.c
View File

@ -1,4 +1,4 @@
/*\
/*
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device
@ -25,10 +25,14 @@
#include <stdio.h>
#include <getopt.h>
#include <err.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <signal.h>
#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
int verbose;
@ -41,14 +45,18 @@ static void usage(const char *name)
" -p, --port=PORT port to listen on (default `1024')\n"
" -o, --offset=OFFSET offset into the image\n"
" -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n"
" -k, --socket=PATH path to the unix socket\n"
" (default '"SOCKET_PATH"')\n"
" -r, --read-only export read-only\n"
" -P, --partition=NUM only expose partition NUM\n"
" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
" -d, --disconnect disconnect the specified device\n"
" -v, --verbose display extra debugging information\n"
" -h, --help display this help and exit\n"
" -V, --version output version information and exit\n"
"\n"
"Report bugs to <anthony@codemonkey.ws>\n"
, name);
, name, "DEVICE");
}
static void version(const char *name)
@ -144,27 +152,51 @@ static int find_partition(BlockDriverState *bs, int partition,
return -1;
}
static void show_parts(const char *device)
{
if (fork() == 0) {
int nbd;
/* linux just needs an open() to trigger
* the partition table update
* but remember to load the module with max_part != 0 :
* modprobe nbd max_part=63
*/
nbd = open(device, O_RDWR);
if (nbd != -1)
close(nbd);
exit(0);
}
}
int main(int argc, char **argv)
{
BlockDriverState *bs;
off_t dev_offset = 0;
off_t offset = 0;
bool readonly = false;
bool disconnect = false;
const char *bindto = "0.0.0.0";
int port = 1024;
int sock, csock;
struct sockaddr_in addr;
socklen_t addr_len = sizeof(addr);
off_t fd_size;
const char *sopt = "hVbo:p:rsP:v";
char *device = NULL;
char *socket = NULL;
char sockpath[128];
const char *sopt = "hVbo:p:rsP:c:dvk:";
struct option lopt[] = {
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
{ "bind", 1, 0, 'b' },
{ "port", 1, 0, 'p' },
{ "socket", 1, 0, 'k' },
{ "offset", 1, 0, 'o' },
{ "read-only", 0, 0, 'r' },
{ "partition", 1, 0, 'P' },
{ "connect", 1, 0, 'c' },
{ "disconnect", 0, 0, 'd' },
{ "snapshot", 0, 0, 's' },
{ "verbose", 0, 0, 'v' },
{ NULL, 0, 0, 0 }
@ -175,6 +207,8 @@ int main(int argc, char **argv)
char *end;
bool snapshot = false;
int partition = -1;
int fd;
int ret;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
@ -213,6 +247,17 @@ int main(int argc, char **argv)
if (partition < 1 || partition > 8)
errx(EINVAL, "Invalid partition %d", partition);
break;
case 'k':
socket = optarg;
if (socket[0] != '/')
errx(EINVAL, "socket path must be absolute\n");
break;
case 'd':
disconnect = true;
break;
case 'c':
device = optarg;
break;
case 'v':
verbose = 1;
break;
@ -236,6 +281,20 @@ int main(int argc, char **argv)
argv[0]);
}
if (disconnect) {
fd = open(argv[optind], O_RDWR);
if (fd == -1)
errx(errno, "Cannot open %s", argv[optind]);
nbd_disconnect(fd);
close(fd);
printf("%s disconnected\n", argv[optind]);
return 0;
}
bdrv_init();
bs = bdrv_new("hda");
@ -251,7 +310,77 @@ int main(int argc, char **argv)
find_partition(bs, partition, &dev_offset, &fd_size))
errx(errno, "Could not find partition %d", partition);
sock = tcp_socket_incoming(bindto, port);
if (device) {
pid_t pid;
if (!verbose)
daemon(0, 0); /* detach client and server */
if (socket == NULL) {
sprintf(sockpath, SOCKET_PATH, basename(device));
socket = sockpath;
}
pid = fork();
if (pid < 0)
return 1;
if (pid != 0) {
off_t size;
size_t blocksize;
ret = 0;
bdrv_close(bs);
do {
sock = unix_socket_outgoing(socket);
if (sock == -1) {
if (errno != ENOENT && errno != ECONNREFUSED)
goto out;
sleep(1); /* wait children */
}
} while (sock == -1);
fd = open(device, O_RDWR);
if (fd == -1) {
ret = 1;
goto out;
}
ret = nbd_receive_negotiate(sock, &size, &blocksize);
if (ret == -1) {
ret = 1;
goto out;
}
ret = nbd_init(fd, sock, size, blocksize);
if (ret == -1) {
ret = 1;
goto out;
}
printf("NBD device %s is now connected to file %s\n",
device, argv[optind]);
/* update partition table */
show_parts(device);
nbd_client(fd, sock);
close(fd);
out:
kill(pid, SIGTERM);
unlink(socket);
return ret;
}
/* children */
}
if (socket) {
sock = unix_socket_incoming(socket);
} else {
sock = tcp_socket_incoming(bindto, port);
}
if (sock == -1)
return 1;
@ -270,6 +399,8 @@ int main(int argc, char **argv)
close(csock);
close(sock);
bdrv_close(bs);
if (socket)
unlink(socket);
return 0;
}

6
qemu-nbd.texi
View File

@ -20,10 +20,16 @@ Export Qemu disk image using NBD protocol.
offset into the image
@item -b, --bind=IFACE
interface to bind to (default `0.0.0.0')
@item -k, --socket=PATH
Use a unix socket with path PATH
@item -r, --read-only
export read-only
@item -P, --partition=NUM
only expose partition NUM
@item -c, --connect
connect FILE to NBD device DEV
@item -d, --disconnect
disconnect the specified device
@item -v, --verbose
display extra debugging information
@item -h, --help