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qemu/qemu-nbd.c
Christoph Hellwig 72aef7318f use qemu_blockalign consistently 
Use qemu_blockalign for all allocations in the block layer.  This allows
increasing the required alignment, which is need to support O_DIRECT on
devices with large block sizes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-09-21 15:39:42 +02:00

502 lines
14 KiB
C
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/*
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device
*
* 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; under version 2 of the License.
*
* 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 <qemu-common.h>
#include "block_int.h"
#include "nbd.h"
#include <stdarg.h>
#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>
#include <libgen.h>
#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
#define NBD_BUFFER_SIZE (1024*1024)
static int verbose;
static void usage(const char *name)
{
printf(
"Usage: %s [OPTIONS] FILE\n"
"QEMU Disk Network Block Device Server\n"
"\n"
" -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"
" -s, --snapshot use snapshot file\n"
" -n, --nocache disable host cache\n"
" -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"
"\n"
"Report bugs to <anthony@codemonkey.ws>\n"
, name, "DEVICE");
}
static void version(const char *name)
{
printf(
"%s version 0.0.1\n"
"Written by Anthony Liguori.\n"
"\n"
"Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
"This is free software; see the source for copying conditions. There is NO\n"
"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
, name);
}
struct partition_record
{
uint8_t bootable;
uint8_t start_head;
uint32_t start_cylinder;
uint8_t start_sector;
uint8_t system;
uint8_t end_head;
uint8_t end_cylinder;
uint8_t end_sector;
uint32_t start_sector_abs;
uint32_t nb_sectors_abs;
};
static void read_partition(uint8_t *p, struct partition_record *r)
{
r->bootable = p[0];
r->start_head = p[1];
r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
r->start_sector = p[2] & 0x3f;
r->system = p[4];
r->end_head = p[5];
r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
r->end_sector = p[6] & 0x3f;
r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24;
r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24;
}
static int find_partition(BlockDriverState *bs, int partition,
off_t *offset, off_t *size)
{
struct partition_record mbr[4];
uint8_t data[512];
int i;
int ext_partnum = 4;
int ret;
if ((ret = bdrv_read(bs, 0, data, 1)) < 0) {
errno = -ret;
err(EXIT_FAILURE, "error while reading");
}
if (data[510] != 0x55 || data[511] != 0xaa) {
errno = -EINVAL;
return -1;
}
for (i = 0; i < 4; i++) {
read_partition(&data[446 + 16 * i], &mbr[i]);
if (!mbr[i].nb_sectors_abs)
continue;
if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
struct partition_record ext[4];
uint8_t data1[512];
int j;
if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) {
errno = -ret;
err(EXIT_FAILURE, "error while reading");
}
for (j = 0; j < 4; j++) {
read_partition(&data1[446 + 16 * j], &ext[j]);
if (!ext[j].nb_sectors_abs)
continue;
if ((ext_partnum + j + 1) == partition) {
*offset = (uint64_t)ext[j].start_sector_abs << 9;
*size = (uint64_t)ext[j].nb_sectors_abs << 9;
return 0;
}
}
ext_partnum += 4;
} else if ((i + 1) == partition) {
*offset = (uint64_t)mbr[i].start_sector_abs << 9;
*size = (uint64_t)mbr[i].nb_sectors_abs << 9;
return 0;
}
}
errno = -ENOENT;
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;
struct sockaddr_in addr;
socklen_t addr_len = sizeof(addr);
off_t fd_size;
char *device = NULL;
char *socket = NULL;
char sockpath[128];
const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t";
struct option lopt[] = {
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
{ "bind", 1, NULL, 'b' },
{ "port", 1, NULL, 'p' },
{ "socket", 1, NULL, 'k' },
{ "offset", 1, NULL, 'o' },
{ "read-only", 0, NULL, 'r' },
{ "partition", 1, NULL, 'P' },
{ "connect", 1, NULL, 'c' },
{ "disconnect", 0, NULL, 'd' },
{ "snapshot", 0, NULL, 's' },
{ "nocache", 0, NULL, 'n' },
{ "shared", 1, NULL, 'e' },
{ "persistent", 0, NULL, 't' },
{ "verbose", 0, NULL, 'v' },
{ NULL, 0, NULL, 0 }
};
int ch;
int opt_ind = 0;
int li;
char *end;
int flags = BDRV_O_RDWR;
int partition = -1;
int ret;
int shared = 1;
uint8_t *data;
fd_set fds;
int *sharing_fds;
int fd;
int i;
int nb_fds = 0;
int max_fd;
int persistent = 0;
uint32_t nbdflags;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
case 's':
flags |= BDRV_O_SNAPSHOT;
break;
case 'n':
flags |= BDRV_O_NOCACHE;
break;
case 'b':
bindto = optarg;
break;
case 'p':
li = strtol(optarg, &end, 0);
if (*end) {
errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
}
if (li < 1 || li > 65535) {
errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
}
port = (uint16_t)li;
break;
case 'o':
dev_offset = strtoll (optarg, &end, 0);
if (*end) {
errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
}
if (dev_offset < 0) {
errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
}
break;
case 'r':
readonly = true;
flags &= ~BDRV_O_RDWR;
break;
case 'P':
partition = strtol(optarg, &end, 0);
if (*end)
errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
if (partition < 1 || partition > 8)
errx(EXIT_FAILURE, "Invalid partition %d", partition);
break;
case 'k':
socket = optarg;
if (socket[0] != '/')
errx(EXIT_FAILURE, "socket path must be absolute\n");
break;
case 'd':
disconnect = true;
break;
case 'c':
device = optarg;
break;
case 'e':
shared = strtol(optarg, &end, 0);
if (*end) {
errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
}
if (shared < 1) {
errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
}
break;
case 't':
persistent = 1;
break;
case 'v':
verbose = 1;
break;
case 'V':
version(argv[0]);
exit(0);
break;
case 'h':
usage(argv[0]);
exit(0);
break;
case '?':
errx(EXIT_FAILURE, "Try `%s --help' for more information.",
argv[0]);
}
}
if ((argc - optind) != 1) {
errx(EXIT_FAILURE, "Invalid number of argument.\n"
"Try `%s --help' for more information.",
argv[0]);
}
if (disconnect) {
fd = open(argv[optind], O_RDWR);
if (fd == -1)
err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
nbd_disconnect(fd);
close(fd);
printf("%s disconnected\n", argv[optind]);
return 0;
}
bdrv_init();
bs = bdrv_new("hda");
if (bs == NULL)
return 1;
if ((ret = bdrv_open(bs, argv[optind], flags, NULL)) < 0) {
errno = -ret;
err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]);
}
fd_size = bs->total_sectors * 512;
if (partition != -1 &&
find_partition(bs, partition, &dev_offset, &fd_size))
err(EXIT_FAILURE, "Could not find partition %d", partition);
if (device) {
pid_t pid;
int sock;
/* want to fail before daemonizing */
if (access(device, R_OK|W_OK) == -1) {
err(EXIT_FAILURE, "Could not access '%s'", device);
}
if (!verbose) {
/* detach client and server */
if (daemon(0, 0) == -1) {
err(EXIT_FAILURE, "Failed to daemonize");
}
}
if (socket == NULL) {
snprintf(sockpath, sizeof(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) {
ret = 1;
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, NULL, &nbdflags,
&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);
ret = nbd_client(fd);
if (ret) {
ret = 1;
}
close(fd);
out:
kill(pid, SIGTERM);
unlink(socket);
return ret;
}
/* children */
}
sharing_fds = qemu_malloc((shared + 1) * sizeof(int));
if (socket) {
sharing_fds[0] = unix_socket_incoming(socket);
} else {
sharing_fds[0] = tcp_socket_incoming(bindto, port);
}
if (sharing_fds[0] == -1)
return 1;
max_fd = sharing_fds[0];
nb_fds++;
data = qemu_blockalign(bs, NBD_BUFFER_SIZE);
if (data == NULL)
errx(EXIT_FAILURE, "Cannot allocate data buffer");
do {
FD_ZERO(&fds);
for (i = 0; i < nb_fds; i++)
FD_SET(sharing_fds[i], &fds);
ret = select(max_fd + 1, &fds, NULL, NULL, NULL);
if (ret == -1)
break;
if (FD_ISSET(sharing_fds[0], &fds))
ret--;
for (i = 1; i < nb_fds && ret; i++) {
if (FD_ISSET(sharing_fds[i], &fds)) {
if (nbd_trip(bs, sharing_fds[i], fd_size, dev_offset,
&offset, readonly, data, NBD_BUFFER_SIZE) != 0) {
close(sharing_fds[i]);
nb_fds--;
sharing_fds[i] = sharing_fds[nb_fds];
i--;
}
ret--;
}
}
/* new connection ? */
if (FD_ISSET(sharing_fds[0], &fds)) {
if (nb_fds < shared + 1) {
sharing_fds[nb_fds] = accept(sharing_fds[0],
(struct sockaddr *)&addr,
&addr_len);
if (sharing_fds[nb_fds] != -1 &&
nbd_negotiate(sharing_fds[nb_fds], fd_size) != -1) {
if (sharing_fds[nb_fds] > max_fd)
max_fd = sharing_fds[nb_fds];
nb_fds++;
}
}
}
} while (persistent || nb_fds > 1);
qemu_vfree(data);
close(sharing_fds[0]);
bdrv_close(bs);
qemu_free(sharing_fds);
if (socket)
unlink(socket);
return 0;
}
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