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Allow QEMU to connect directly to an NBD server, by Laurent Vivier.

Browse source 
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4838 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
ths 2008-07-03 13:41:03 +00:00
parent 3b05a8e91b
commit 75818250ba
9 changed files with 413 additions and 77 deletions
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8
Makefile
View file

@ -42,7 +42,7 @@ recurse-all: $(SUBDIR_RULES)
BLOCK_OBJS=cutils.o qemu-malloc.o
BLOCK_OBJS+=block-cow.o block-qcow.o aes.o block-vmdk.o block-cloop.o
BLOCK_OBJS+=block-dmg.o block-bochs.o block-vpc.o block-vvfat.o
BLOCK_OBJS+=block-qcow2.o block-parallels.o
BLOCK_OBJS+=block-qcow2.o block-parallels.o block-nbd.o
######################################################################
# libqemu_common.a: Target independent part of system emulation. The
@ -50,7 +50,7 @@ BLOCK_OBJS+=block-qcow2.o block-parallels.o
# system emulation, i.e. a single QEMU executable should support all
# CPUs and machines.
OBJS=$(BLOCK_OBJS)
OBJS=nbd.o $(BLOCK_OBJS)
OBJS+=readline.o console.o
OBJS+=block.o
@ -159,7 +159,7 @@ libqemu_user.a: $(USER_OBJS)
rm -f $@
$(AR) rcs $@ $(USER_OBJS)
QEMU_IMG_BLOCK_OBJS = $(BLOCK_OBJS)
QEMU_IMG_BLOCK_OBJS = nbd.o $(BLOCK_OBJS)
ifdef CONFIG_WIN32
QEMU_IMG_BLOCK_OBJS += qemu-img-block-raw-win32.o
else
@ -180,7 +180,7 @@ qemu-img-%.o: %.c
qemu-nbd-%.o: %.c
$(CC) $(CFLAGS) $(CPPFLAGS) -DQEMU_NBD -c -o $@ $<
qemu-nbd$(EXESUF): qemu-nbd.o nbd.o qemu-img-block.o \
qemu-nbd$(EXESUF): qemu-nbd.o qemu-nbd-nbd.o qemu-img-block.o \
osdep.o qemu-nbd-block-raw-posix.o $(BLOCK_OBJS)
$(CC) $(LDFLAGS) -o $@ $^ -lz $(LIBS)

194
block-nbd.c Normal file
View file

@ -0,0 +1,194 @@
/*
* QEMU Block driver for NBD
*
* Copyright (C) 2008 Bull S.A.S.
* Author: Laurent Vivier <Laurent.Vivier@bull;net>
*
* Some parts:
* Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu-common.h"
#include "nbd.h"
#include <sys/types.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
typedef struct BDRVNBDState {
int sock;
off_t size;
size_t blocksize;
} BDRVNBDState;
static int nbd_open(BlockDriverState *bs, const char* filename, int flags)
{
BDRVNBDState *s = bs->opaque;
const char *host;
const char *unixpath;
int sock;
off_t size;
size_t blocksize;
int ret;
if ((flags & BDRV_O_CREAT))
return -EINVAL;
if (!strstart(filename, "nbd:", &host))
return -EINVAL;
if (strstart(host, "unix:", &unixpath)) {
if (unixpath[0] != '/')
return -EINVAL;
sock = unix_socket_outgoing(unixpath);
} else {
uint16_t port;
char *p, *r;
char hostname[128];
pstrcpy(hostname, 128, host);
p = strchr(hostname, ':');
if (p == NULL)
return -EINVAL;
*p = '\0';
p++;
port = strtol(p, &r, 0);
if (r == p)
return -EINVAL;
sock = tcp_socket_outgoing(hostname, port);
}
if (sock == -1)
return -errno;
ret = nbd_receive_negotiate(sock, &size, &blocksize);
if (ret == -1)
return -errno;
s->sock = sock;
s->size = size;
s->blocksize = blocksize;
return 0;
}
static int nbd_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
BDRVNBDState *s = bs->opaque;
struct nbd_request request;
struct nbd_reply reply;
request.type = NBD_CMD_READ;
request.handle = (uint64_t)(intptr_t)bs;
request.from = sector_num * 512;;
request.len = nb_sectors * 512;
if (nbd_send_request(s->sock, &request) == -1)
return -errno;
if (nbd_receive_reply(s->sock, &reply) == -1)
return -errno;
if (reply.error !=0)
return -reply.error;
if (reply.handle != request.handle)
return -EIO;
if (nbd_wr_sync(s->sock, buf, request.len, 1) != request.len)
return -EIO;
return 0;
}
static int nbd_write(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors)
{
BDRVNBDState *s = bs->opaque;
struct nbd_request request;
struct nbd_reply reply;
request.type = NBD_CMD_WRITE;
request.handle = (uint64_t)(intptr_t)bs;
request.from = sector_num * 512;;
request.len = nb_sectors * 512;
if (nbd_send_request(s->sock, &request) == -1)
return -errno;
if (nbd_wr_sync(s->sock, (uint8_t*)buf, request.len, 0) != request.len)
return -EIO;
if (nbd_receive_reply(s->sock, &reply) == -1)
return -errno;
if (reply.error !=0)
return -reply.error;
if (reply.handle != request.handle)
return -EIO;
return 0;
}
static void nbd_close(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
struct nbd_request request;
request.type = NBD_CMD_DISC;
request.handle = (uint64_t)(intptr_t)bs;
request.from = 0;
request.len = 0;
nbd_send_request(s->sock, &request);
close(s->sock);
}
static int64_t nbd_getlength(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
return s->size;
}
BlockDriver bdrv_nbd = {
"nbd",
sizeof(BDRVNBDState),
NULL, /* no probe for protocols */
nbd_open,
nbd_read,
nbd_write,
nbd_close,
.bdrv_getlength = nbd_getlength,
.protocol_name = "nbd",
};

1
block.c
View file

@ -1332,6 +1332,7 @@ void bdrv_init(void)
bdrv_register(&bdrv_vvfat);
bdrv_register(&bdrv_qcow2);
bdrv_register(&bdrv_parallels);
bdrv_register(&bdrv_nbd);
}
void *qemu_aio_get(BlockDriverState *bs, BlockDriverCompletionFunc *cb,

1
block.h
View file

@ -16,6 +16,7 @@ extern BlockDriver bdrv_vpc;
extern BlockDriver bdrv_vvfat;
extern BlockDriver bdrv_qcow2;
extern BlockDriver bdrv_parallels;
extern BlockDriver bdrv_nbd;
typedef struct BlockDriverInfo {
/* in bytes, 0 if irrelevant */

213
nbd.c
View file

@ -1,4 +1,4 @@
/*\
/*
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device
@ -15,7 +15,7 @@
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
\*/
*/
#include "nbd.h"
@ -31,17 +31,21 @@
#include <arpa/inet.h>
#include <netdb.h>
#if defined(QEMU_NBD)
extern int verbose;
#else
static int verbose = 0;
#endif
#define TRACE(msg, ...) do { \
if (verbose) LOG(msg, ## __VA_ARGS__); \
} while(0)
#define LOG(msg, ...) do { \
fprintf(stderr, "%s:%s():L%d: " msg "\n", \
__FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
} while(0)
#define TRACE(msg, ...) do { \
if (verbose) LOG(msg, ## __VA_ARGS__); \
} while(0)
/* This is all part of the "official" NBD API */
#define NBD_REQUEST_MAGIC 0x25609513
@ -59,10 +63,10 @@ extern int verbose;
/* That's all folks */
#define read_sync(fd, buffer, size) wr_sync(fd, buffer, size, true)
#define write_sync(fd, buffer, size) wr_sync(fd, buffer, size, false)
#define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
#define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
static size_t wr_sync(int fd, void *buffer, size_t size, bool do_read)
size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
{
size_t offset = 0;
@ -76,7 +80,7 @@ static size_t wr_sync(int fd, void *buffer, size_t size, bool do_read)
}
/* recoverable error */
if (len == -1 && errno == EAGAIN) {
if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
continue;
}
@ -96,7 +100,7 @@ static size_t wr_sync(int fd, void *buffer, size_t size, bool do_read)
return offset;
}
static int tcp_socket_outgoing(const char *address, uint16_t port)
int tcp_socket_outgoing(const char *address, uint16_t port)
{
int s;
struct in_addr in;
@ -404,16 +408,31 @@ int nbd_client(int fd, int csock)
return ret;
}
int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
off_t *offset, bool readonly, uint8_t *data, int data_size)
int nbd_send_request(int csock, struct nbd_request *request)
{
uint8_t buf[4 + 4 + 8 + 8 + 4];
cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
cpu_to_be32w((uint32_t*)(buf + 4), request->type);
cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
cpu_to_be64w((uint64_t*)(buf + 16), request->from);
cpu_to_be32w((uint32_t*)(buf + 24), request->len);
TRACE("Sending request to client");
if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("writing to socket failed");
errno = EINVAL;
return -1;
}
return 0;
}
static int nbd_receive_request(int csock, struct nbd_request *request)
{
uint8_t buf[4 + 4 + 8 + 8 + 4];
uint32_t magic;
uint32_t type;
uint64_t from;
uint32_t len;
TRACE("Reading request.");
if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("read failed");
@ -422,97 +441,158 @@ int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
}
/* Request
[ 0 .. 3] magic (NBD_REQUEST_MAGIC)
[ 4 .. 7] type (0 == READ, 1 == WRITE)
[ 8 .. 15] handle
[16 .. 23] from
[24 .. 27] len
[ 0 .. 3] magic (NBD_REQUEST_MAGIC)
[ 4 .. 7] type (0 == READ, 1 == WRITE)
[ 8 .. 15] handle
[16 .. 23] from
[24 .. 27] len
*/
magic = be32_to_cpup((uint32_t*)buf);
type = be32_to_cpup((uint32_t*)(buf + 4));
from = be64_to_cpup((uint64_t*)(buf + 16));
len = be32_to_cpup((uint32_t*)(buf + 24));
request->type = be32_to_cpup((uint32_t*)(buf + 4));
request->handle = be64_to_cpup((uint64_t*)(buf + 8));
request->from = be64_to_cpup((uint64_t*)(buf + 16));
request->len = be32_to_cpup((uint32_t*)(buf + 24));
TRACE("Got request: "
"{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
magic, type, from, len);
magic, request->type, request->from, request->len);
if (magic != NBD_REQUEST_MAGIC) {
LOG("invalid magic (got 0x%x)", magic);
errno = EINVAL;
return -1;
}
}
if (len > data_size) {
LOG("len (%u) is larger than max len (%u)",
len, data_size);
int nbd_receive_reply(int csock, struct nbd_reply *reply)
{
uint8_t buf[4 + 4 + 8];
uint32_t magic;
memset(buf, 0xAA, sizeof(buf));
if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("read failed");
errno = EINVAL;
return -1;
}
if ((from + len) < from) {
/* Reply
[ 0 .. 3] magic (NBD_REPLY_MAGIC)
[ 4 .. 7] error (0 == no error)
[ 7 .. 15] handle
*/
magic = be32_to_cpup((uint32_t*)buf);
reply->error = be32_to_cpup((uint32_t*)(buf + 4));
reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
TRACE("Got reply: "
"{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
magic, reply->error, reply->handle);
if (magic != NBD_REPLY_MAGIC) {
LOG("invalid magic (got 0x%x)", magic);
errno = EINVAL;
return -1;
}
return 0;
}
static int nbd_send_reply(int csock, struct nbd_reply *reply)
{
uint8_t buf[4 + 4 + 8];
/* Reply
[ 0 .. 3] magic (NBD_REPLY_MAGIC)
[ 4 .. 7] error (0 == no error)
[ 7 .. 15] handle
*/
cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
cpu_to_be32w((uint32_t*)(buf + 4), reply->error);
cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
TRACE("Sending response to client");
if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("writing to socket failed");
errno = EINVAL;
return -1;
}
return 0;
}
int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
off_t *offset, bool readonly, uint8_t *data, int data_size)
{
struct nbd_request request;
struct nbd_reply reply;
TRACE("Reading request.");
if (nbd_receive_request(csock, &request) == -1)
return -1;
if (request.len > data_size) {
LOG("len (%u) is larger than max len (%u)",
request.len, data_size);
errno = EINVAL;
return -1;
}
if ((request.from + request.len) < request.from) {
LOG("integer overflow detected! "
"you're probably being attacked");
errno = EINVAL;
return -1;
}
if ((from + len) > size) {
if ((request.from + request.len) > size) {
LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
", Offset: %" PRIu64 "\n",
from, len, size, dev_offset);
request.from, request.len, size, dev_offset);
LOG("requested operation past EOF--bad client?");
errno = EINVAL;
return -1;
}
/* Reply
[ 0 .. 3] magic (NBD_REPLY_MAGIC)
[ 4 .. 7] error (0 == no error)
[ 7 .. 15] handle
*/
cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
cpu_to_be32w((uint32_t*)(buf + 4), 0);
TRACE("Decoding type");
switch (type) {
case 0:
reply.handle = request.handle;
reply.error = 0;
switch (request.type) {
case NBD_CMD_READ:
TRACE("Request type is READ");
if (bdrv_read(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
if (bdrv_read(bs, (request.from + dev_offset) / 512, data,
request.len / 512) == -1) {
LOG("reading from file failed");
errno = EINVAL;
return -1;
}
*offset += len;
*offset += request.len;
TRACE("Read %u byte(s)", len);
TRACE("Read %u byte(s)", request.len);
TRACE("Sending OK response");
if (write_sync(csock, buf, 16) != 16) {
LOG("writing to socket failed");
errno = EINVAL;
if (nbd_send_reply(csock, &reply) == -1)
return -1;
}
TRACE("Sending data to client");
if (write_sync(csock, data, len) != len) {
if (write_sync(csock, data, request.len) != request.len) {
LOG("writing to socket failed");
errno = EINVAL;
return -1;
}
break;
case 1:
case NBD_CMD_WRITE:
TRACE("Request type is WRITE");
TRACE("Reading %u byte(s)", len);
TRACE("Reading %u byte(s)", request.len);
if (read_sync(csock, data, len) != len) {
if (read_sync(csock, data, request.len) != request.len) {
LOG("reading from socket failed");
errno = EINVAL;
return -1;
@ -520,34 +600,29 @@ int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
if (readonly) {
TRACE("Server is read-only, return error");
cpu_to_be32w((uint32_t*)(buf + 4), 1);
reply.error = 1;
} else {
TRACE("Writing to device");
if (bdrv_write(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
if (bdrv_write(bs, (request.from + dev_offset) / 512,
data, request.len / 512) == -1) {
LOG("writing to file failed");
errno = EINVAL;
return -1;
}
*offset += len;
*offset += request.len;
}
TRACE("Sending response to client");
if (write_sync(csock, buf, 16) != 16) {
LOG("writing to socket failed");
errno = EINVAL;
if (nbd_send_reply(csock, &reply) == -1)
return -1;
}
break;
case 2:
case NBD_CMD_DISC:
TRACE("Request type is DISCONNECT");
errno = 0;
return 1;
default:
LOG("invalid request type (%u) received", type);
LOG("invalid request type (%u) received", request.type);
errno = EINVAL;
return -1;
}

26
nbd.h
View file

@ -1,4 +1,4 @@
/*\
/*
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device
@ -15,7 +15,7 @@
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
\*/
*/
#ifndef NBD_H
#define NBD_H
@ -26,6 +26,26 @@
#include <qemu-common.h>
#include "block_int.h"
struct nbd_request {
uint32_t type;
uint64_t handle;
uint64_t from;
uint32_t len;
};
struct nbd_reply {
uint32_t error;
uint64_t handle;
};
enum {
NBD_CMD_READ = 0,
NBD_CMD_WRITE = 1,
NBD_CMD_DISC = 2
};
size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);
int tcp_socket_outgoing(const char *address, uint16_t port);
int tcp_socket_incoming(const char *address, uint16_t port);
int unix_socket_outgoing(const char *path);
int unix_socket_incoming(const char *path);
@ -33,6 +53,8 @@ int unix_socket_incoming(const char *path);
int nbd_negotiate(BlockDriverState *bs, int csock, off_t size);
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_send_request(int csock, struct nbd_request *request);
int nbd_receive_reply(int csock, struct nbd_reply *reply);
int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
off_t *offset, bool readonly, uint8_t *data, int data_size);
int nbd_client(int fd, int csock);

35
qemu-doc.texi
View file

@ -1321,6 +1321,7 @@ snapshots.
* qemu_nbd_invocation:: qemu-nbd Invocation
* host_drives:: Using host drives
* disk_images_fat_images:: Virtual FAT disk images
* disk_images_nbd:: NBD access
@end menu
@node disk_images_quickstart
@ -1503,6 +1504,40 @@ What you should @emph{never} do:
@item write to the FAT directory on the host system while accessing it with the guest system.
@end itemize
@node disk_images_nbd
@subsection NBD access
QEMU can access directly to block device exported using the Network Block Device
protocol.
@example
qemu linux.img -hdb nbd:my_nbd_server.mydomain.org:1024
@end example
If the NBD server is located on the same host, you can use an unix socket instead
of an inet socket:
@example
qemu linux.img -hdb nbd:unix:/tmp/my_socket
@end example
In this case, the block device must be exported using qemu-nbd:
@example
qemu-nbd --socket=/tmp/my_socket my_disk.qcow2
@end example
The use of qemu-nbd allows to share a disk between several guests:
@example
qemu-nbd --socket=/tmp/my_socket --share=2 my_disk.qcow2
@end example
and then you can use it with two guests:
@example
qemu linux1.img -hdb nbd:unix:/tmp/my_socket
qemu linux2.img -hdb nbd:unix:/tmp/my_socket
@end example
@node pcsys_network
@section Network emulation

10
qemu-nbd.c
View file

@ -56,6 +56,7 @@ static void usage(const char *name)
" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
" -d, --disconnect disconnect the specified device\n"
" -e, --shared=NUM device can be shared by NUM clients (default '1')\n"
" -t, --persistent don't exit on the last connection\n"
" -v, --verbose display extra debugging information\n"
" -h, --help display this help and exit\n"
" -V, --version output version information and exit\n"
@ -189,7 +190,7 @@ int main(int argc, char **argv)
char *device = NULL;
char *socket = NULL;
char sockpath[128];
const char *sopt = "hVbo:p:rsnP:c:dvk:e:";
const char *sopt = "hVbo:p:rsnP:c:dvk:e:t";
struct option lopt[] = {
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
@ -204,6 +205,7 @@ int main(int argc, char **argv)
{ "snapshot", 0, 0, 's' },
{ "nocache", 0, 0, 'n' },
{ "shared", 1, 0, 'e' },
{ "persistent", 0, 0, 't' },
{ "verbose", 0, 0, 'v' },
{ NULL, 0, 0, 0 }
};
@ -222,6 +224,7 @@ int main(int argc, char **argv)
int i;
int nb_fds = 0;
int max_fd;
int persistent = 0;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
@ -283,6 +286,9 @@ int main(int argc, char **argv)
errx(EINVAL, "Shared device number must be greater than 0\n");
}
break;
case 't':
persistent = 1;
break;
case 'v':
verbose = 1;
break;
@ -459,7 +465,7 @@ int main(int argc, char **argv)
}
}
}
} while (nb_fds > 1);
} while (persistent || nb_fds > 1);
qemu_free(data);
close(sharing_fds[0]);

2
qemu-nbd.texi
View file

@ -36,6 +36,8 @@ Export Qemu disk image using NBD protocol.
disconnect the specified device
@item -e, --shared=NUM
device can be shared by NUM clients (default '1')
@item -t, --persistent
don't exit on the last connection
@item -v, --verbose
display extra debugging information
@item -h, --help