/*

* 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 `%d')\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, NBD_DEFAULT_PORT, "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

};

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 = NBD_DEFAULT_PORT;

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;

}