1 /* 2 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> 3 * 4 * Network Block Device 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; under version 2 of the License. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #include "qemu-common.h" 20 #include "block_int.h" 21 #include "nbd.h" 22 23 #include <stdarg.h> 24 #include <stdio.h> 25 #include <getopt.h> 26 #include <err.h> 27 #include <sys/types.h> 28 #include <sys/socket.h> 29 #include <netinet/in.h> 30 #include <netinet/tcp.h> 31 #include <arpa/inet.h> 32 #include <signal.h> 33 #include <libgen.h> 34 35 #define SOCKET_PATH "/var/lock/qemu-nbd-%s" 36 37 #define NBD_BUFFER_SIZE (1024*1024) 38 39 static int verbose; 40 41 static void usage(const char *name) 42 { 43 printf( 44 "Usage: %s [OPTIONS] FILE\n" 45 "QEMU Disk Network Block Device Server\n" 46 "\n" 47 " -p, --port=PORT port to listen on (default `%d')\n" 48 " -o, --offset=OFFSET offset into the image\n" 49 " -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n" 50 " -k, --socket=PATH path to the unix socket\n" 51 " (default '"SOCKET_PATH"')\n" 52 " -r, --read-only export read-only\n" 53 " -P, --partition=NUM only expose partition NUM\n" 54 " -s, --snapshot use snapshot file\n" 55 " -n, --nocache disable host cache\n" 56 " -c, --connect=DEV connect FILE to the local NBD device DEV\n" 57 " -d, --disconnect disconnect the specified device\n" 58 " -e, --shared=NUM device can be shared by NUM clients (default '1')\n" 59 " -t, --persistent don't exit on the last connection\n" 60 " -v, --verbose display extra debugging information\n" 61 " -h, --help display this help and exit\n" 62 " -V, --version output version information and exit\n" 63 "\n" 64 "Report bugs to <anthony@codemonkey.ws>\n" 65 , name, NBD_DEFAULT_PORT, "DEVICE"); 66 } 67 68 static void version(const char *name) 69 { 70 printf( 71 "%s version 0.0.1\n" 72 "Written by Anthony Liguori.\n" 73 "\n" 74 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n" 75 "This is free software; see the source for copying conditions. There is NO\n" 76 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n" 77 , name); 78 } 79 80 struct partition_record 81 { 82 uint8_t bootable; 83 uint8_t start_head; 84 uint32_t start_cylinder; 85 uint8_t start_sector; 86 uint8_t system; 87 uint8_t end_head; 88 uint8_t end_cylinder; 89 uint8_t end_sector; 90 uint32_t start_sector_abs; 91 uint32_t nb_sectors_abs; 92 }; 93 94 static void read_partition(uint8_t *p, struct partition_record *r) 95 { 96 r->bootable = p[0]; 97 r->start_head = p[1]; 98 r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300); 99 r->start_sector = p[2] & 0x3f; 100 r->system = p[4]; 101 r->end_head = p[5]; 102 r->end_cylinder = p[7] | ((p[6] << 2) & 0x300); 103 r->end_sector = p[6] & 0x3f; 104 r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24; 105 r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24; 106 } 107 108 static int find_partition(BlockDriverState *bs, int partition, 109 off_t *offset, off_t *size) 110 { 111 struct partition_record mbr[4]; 112 uint8_t data[512]; 113 int i; 114 int ext_partnum = 4; 115 int ret; 116 117 if ((ret = bdrv_read(bs, 0, data, 1)) < 0) { 118 errno = -ret; 119 err(EXIT_FAILURE, "error while reading"); 120 } 121 122 if (data[510] != 0x55 || data[511] != 0xaa) { 123 errno = -EINVAL; 124 return -1; 125 } 126 127 for (i = 0; i < 4; i++) { 128 read_partition(&data[446 + 16 * i], &mbr[i]); 129 130 if (!mbr[i].nb_sectors_abs) 131 continue; 132 133 if (mbr[i].system == 0xF || mbr[i].system == 0x5) { 134 struct partition_record ext[4]; 135 uint8_t data1[512]; 136 int j; 137 138 if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) { 139 errno = -ret; 140 err(EXIT_FAILURE, "error while reading"); 141 } 142 143 for (j = 0; j < 4; j++) { 144 read_partition(&data1[446 + 16 * j], &ext[j]); 145 if (!ext[j].nb_sectors_abs) 146 continue; 147 148 if ((ext_partnum + j + 1) == partition) { 149 *offset = (uint64_t)ext[j].start_sector_abs << 9; 150 *size = (uint64_t)ext[j].nb_sectors_abs << 9; 151 return 0; 152 } 153 } 154 ext_partnum += 4; 155 } else if ((i + 1) == partition) { 156 *offset = (uint64_t)mbr[i].start_sector_abs << 9; 157 *size = (uint64_t)mbr[i].nb_sectors_abs << 9; 158 return 0; 159 } 160 } 161 162 errno = -ENOENT; 163 return -1; 164 } 165 166 static void show_parts(const char *device) 167 { 168 if (fork() == 0) { 169 int nbd; 170 171 /* linux just needs an open() to trigger 172 * the partition table update 173 * but remember to load the module with max_part != 0 : 174 * modprobe nbd max_part=63 175 */ 176 nbd = open(device, O_RDWR); 177 if (nbd != -1) 178 close(nbd); 179 exit(0); 180 } 181 } 182 183 int main(int argc, char **argv) 184 { 185 BlockDriverState *bs; 186 off_t dev_offset = 0; 187 off_t offset = 0; 188 uint32_t nbdflags = 0; 189 bool disconnect = false; 190 const char *bindto = "0.0.0.0"; 191 int port = NBD_DEFAULT_PORT; 192 struct sockaddr_in addr; 193 socklen_t addr_len = sizeof(addr); 194 off_t fd_size; 195 char *device = NULL; 196 char *socket = NULL; 197 char sockpath[128]; 198 const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t"; 199 struct option lopt[] = { 200 { "help", 0, NULL, 'h' }, 201 { "version", 0, NULL, 'V' }, 202 { "bind", 1, NULL, 'b' }, 203 { "port", 1, NULL, 'p' }, 204 { "socket", 1, NULL, 'k' }, 205 { "offset", 1, NULL, 'o' }, 206 { "read-only", 0, NULL, 'r' }, 207 { "partition", 1, NULL, 'P' }, 208 { "connect", 1, NULL, 'c' }, 209 { "disconnect", 0, NULL, 'd' }, 210 { "snapshot", 0, NULL, 's' }, 211 { "nocache", 0, NULL, 'n' }, 212 { "shared", 1, NULL, 'e' }, 213 { "persistent", 0, NULL, 't' }, 214 { "verbose", 0, NULL, 'v' }, 215 { NULL, 0, NULL, 0 } 216 }; 217 int ch; 218 int opt_ind = 0; 219 int li; 220 char *end; 221 int flags = BDRV_O_RDWR; 222 int partition = -1; 223 int ret; 224 int shared = 1; 225 uint8_t *data; 226 fd_set fds; 227 int *sharing_fds; 228 int fd; 229 int i; 230 int nb_fds = 0; 231 int max_fd; 232 int persistent = 0; 233 234 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { 235 switch (ch) { 236 case 's': 237 flags |= BDRV_O_SNAPSHOT; 238 break; 239 case 'n': 240 flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; 241 break; 242 case 'b': 243 bindto = optarg; 244 break; 245 case 'p': 246 li = strtol(optarg, &end, 0); 247 if (*end) { 248 errx(EXIT_FAILURE, "Invalid port `%s'", optarg); 249 } 250 if (li < 1 || li > 65535) { 251 errx(EXIT_FAILURE, "Port out of range `%s'", optarg); 252 } 253 port = (uint16_t)li; 254 break; 255 case 'o': 256 dev_offset = strtoll (optarg, &end, 0); 257 if (*end) { 258 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg); 259 } 260 if (dev_offset < 0) { 261 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg); 262 } 263 break; 264 case 'r': 265 nbdflags |= NBD_FLAG_READ_ONLY; 266 flags &= ~BDRV_O_RDWR; 267 break; 268 case 'P': 269 partition = strtol(optarg, &end, 0); 270 if (*end) 271 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg); 272 if (partition < 1 || partition > 8) 273 errx(EXIT_FAILURE, "Invalid partition %d", partition); 274 break; 275 case 'k': 276 socket = optarg; 277 if (socket[0] != '/') 278 errx(EXIT_FAILURE, "socket path must be absolute\n"); 279 break; 280 case 'd': 281 disconnect = true; 282 break; 283 case 'c': 284 device = optarg; 285 break; 286 case 'e': 287 shared = strtol(optarg, &end, 0); 288 if (*end) { 289 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg); 290 } 291 if (shared < 1) { 292 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n"); 293 } 294 break; 295 case 't': 296 persistent = 1; 297 break; 298 case 'v': 299 verbose = 1; 300 break; 301 case 'V': 302 version(argv[0]); 303 exit(0); 304 break; 305 case 'h': 306 usage(argv[0]); 307 exit(0); 308 break; 309 case '?': 310 errx(EXIT_FAILURE, "Try `%s --help' for more information.", 311 argv[0]); 312 } 313 } 314 315 if ((argc - optind) != 1) { 316 errx(EXIT_FAILURE, "Invalid number of argument.\n" 317 "Try `%s --help' for more information.", 318 argv[0]); 319 } 320 321 if (disconnect) { 322 fd = open(argv[optind], O_RDWR); 323 if (fd == -1) 324 err(EXIT_FAILURE, "Cannot open %s", argv[optind]); 325 326 nbd_disconnect(fd); 327 328 close(fd); 329 330 printf("%s disconnected\n", argv[optind]); 331 332 return 0; 333 } 334 335 bdrv_init(); 336 337 bs = bdrv_new("hda"); 338 339 if ((ret = bdrv_open(bs, argv[optind], flags, NULL)) < 0) { 340 errno = -ret; 341 err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]); 342 } 343 344 fd_size = bs->total_sectors * 512; 345 346 if (partition != -1 && 347 find_partition(bs, partition, &dev_offset, &fd_size)) 348 err(EXIT_FAILURE, "Could not find partition %d", partition); 349 350 if (device) { 351 pid_t pid; 352 int sock; 353 354 /* want to fail before daemonizing */ 355 if (access(device, R_OK|W_OK) == -1) { 356 err(EXIT_FAILURE, "Could not access '%s'", device); 357 } 358 359 if (!verbose) { 360 /* detach client and server */ 361 if (qemu_daemon(0, 0) == -1) { 362 err(EXIT_FAILURE, "Failed to daemonize"); 363 } 364 } 365 366 if (socket == NULL) { 367 snprintf(sockpath, sizeof(sockpath), SOCKET_PATH, 368 basename(device)); 369 socket = sockpath; 370 } 371 372 pid = fork(); 373 if (pid < 0) 374 return 1; 375 if (pid != 0) { 376 off_t size; 377 size_t blocksize; 378 379 ret = 0; 380 bdrv_close(bs); 381 382 do { 383 sock = unix_socket_outgoing(socket); 384 if (sock == -1) { 385 if (errno != ENOENT && errno != ECONNREFUSED) { 386 ret = 1; 387 goto out; 388 } 389 sleep(1); /* wait children */ 390 } 391 } while (sock == -1); 392 393 fd = open(device, O_RDWR); 394 if (fd == -1) { 395 ret = 1; 396 goto out; 397 } 398 399 ret = nbd_receive_negotiate(sock, NULL, &nbdflags, 400 &size, &blocksize); 401 if (ret == -1) { 402 ret = 1; 403 goto out; 404 } 405 406 ret = nbd_init(fd, sock, nbdflags, size, blocksize); 407 if (ret == -1) { 408 ret = 1; 409 goto out; 410 } 411 412 printf("NBD device %s is now connected to file %s\n", 413 device, argv[optind]); 414 415 /* update partition table */ 416 417 show_parts(device); 418 419 ret = nbd_client(fd); 420 if (ret) { 421 ret = 1; 422 } 423 close(fd); 424 out: 425 kill(pid, SIGTERM); 426 unlink(socket); 427 428 return ret; 429 } 430 /* children */ 431 } 432 433 sharing_fds = g_malloc((shared + 1) * sizeof(int)); 434 435 if (socket) { 436 sharing_fds[0] = unix_socket_incoming(socket); 437 } else { 438 sharing_fds[0] = tcp_socket_incoming(bindto, port); 439 } 440 441 if (sharing_fds[0] == -1) 442 return 1; 443 max_fd = sharing_fds[0]; 444 nb_fds++; 445 446 data = qemu_blockalign(bs, NBD_BUFFER_SIZE); 447 if (data == NULL) 448 errx(EXIT_FAILURE, "Cannot allocate data buffer"); 449 450 do { 451 452 FD_ZERO(&fds); 453 for (i = 0; i < nb_fds; i++) 454 FD_SET(sharing_fds[i], &fds); 455 456 ret = select(max_fd + 1, &fds, NULL, NULL, NULL); 457 if (ret == -1) 458 break; 459 460 if (FD_ISSET(sharing_fds[0], &fds)) 461 ret--; 462 for (i = 1; i < nb_fds && ret; i++) { 463 if (FD_ISSET(sharing_fds[i], &fds)) { 464 if (nbd_trip(bs, sharing_fds[i], fd_size, dev_offset, 465 &offset, nbdflags, data, NBD_BUFFER_SIZE) != 0) { 466 close(sharing_fds[i]); 467 nb_fds--; 468 sharing_fds[i] = sharing_fds[nb_fds]; 469 i--; 470 } 471 ret--; 472 } 473 } 474 /* new connection ? */ 475 if (FD_ISSET(sharing_fds[0], &fds)) { 476 if (nb_fds < shared + 1) { 477 sharing_fds[nb_fds] = accept(sharing_fds[0], 478 (struct sockaddr *)&addr, 479 &addr_len); 480 if (sharing_fds[nb_fds] != -1 && 481 nbd_negotiate(sharing_fds[nb_fds], fd_size, nbdflags) != -1) { 482 if (sharing_fds[nb_fds] > max_fd) 483 max_fd = sharing_fds[nb_fds]; 484 nb_fds++; 485 } 486 } 487 } 488 } while (persistent || nb_fds > 1); 489 qemu_vfree(data); 490 491 close(sharing_fds[0]); 492 bdrv_close(bs); 493 g_free(sharing_fds); 494 if (socket) 495 unlink(socket); 496 497 return 0; 498 } 499