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, write to the Free Software 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 */ 19 20 #include <qemu-common.h> 21 #include "block_int.h" 22 #include "nbd.h" 23 24 #include <stdarg.h> 25 #include <stdio.h> 26 #include <getopt.h> 27 #include <err.h> 28 #include <sys/types.h> 29 #include <sys/socket.h> 30 #include <netinet/in.h> 31 #include <netinet/tcp.h> 32 #include <arpa/inet.h> 33 #include <signal.h> 34 35 #define SOCKET_PATH "/var/lock/qemu-nbd-%s" 36 37 #define NBD_BUFFER_SIZE (1024*1024) 38 39 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 `1024')\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, "DEVICE"); 66 } 67 68 static void version(const char *name) 69 { 70 printf( 71 "qemu-nbd 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 ); 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; 115 116 if (bdrv_read(bs, 0, data, 1)) 117 errx(EINVAL, "error while reading"); 118 119 if (data[510] != 0x55 || data[511] != 0xaa) { 120 errno = -EINVAL; 121 return -1; 122 } 123 124 for (i = 0; i < 4; i++) { 125 read_partition(&data[446 + 16 * i], &mbr[i]); 126 127 if (!mbr[i].nb_sectors_abs) 128 continue; 129 130 if (mbr[i].system == 0xF || mbr[i].system == 0x5) { 131 struct partition_record ext[4]; 132 uint8_t data1[512]; 133 int j; 134 135 if (bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) 136 errx(EINVAL, "error while reading"); 137 138 for (j = 0; j < 4; j++) { 139 read_partition(&data1[446 + 16 * j], &ext[j]); 140 if (!ext[j].nb_sectors_abs) 141 continue; 142 143 if ((ext_partnum + j + 1) == partition) { 144 *offset = (uint64_t)ext[j].start_sector_abs << 9; 145 *size = (uint64_t)ext[j].nb_sectors_abs << 9; 146 return 0; 147 } 148 } 149 ext_partnum += 4; 150 } else if ((i + 1) == partition) { 151 *offset = (uint64_t)mbr[i].start_sector_abs << 9; 152 *size = (uint64_t)mbr[i].nb_sectors_abs << 9; 153 return 0; 154 } 155 } 156 157 errno = -ENOENT; 158 return -1; 159 } 160 161 static void show_parts(const char *device) 162 { 163 if (fork() == 0) { 164 int nbd; 165 166 /* linux just needs an open() to trigger 167 * the partition table update 168 * but remember to load the module with max_part != 0 : 169 * modprobe nbd max_part=63 170 */ 171 nbd = open(device, O_RDWR); 172 if (nbd != -1) 173 close(nbd); 174 exit(0); 175 } 176 } 177 178 int main(int argc, char **argv) 179 { 180 BlockDriverState *bs; 181 off_t dev_offset = 0; 182 off_t offset = 0; 183 bool readonly = false; 184 bool disconnect = false; 185 const char *bindto = "0.0.0.0"; 186 int port = 1024; 187 struct sockaddr_in addr; 188 socklen_t addr_len = sizeof(addr); 189 off_t fd_size; 190 char *device = NULL; 191 char *socket = NULL; 192 char sockpath[128]; 193 const char *sopt = "hVbo:p:rsnP:c:dvk:e:t"; 194 struct option lopt[] = { 195 { "help", 0, 0, 'h' }, 196 { "version", 0, 0, 'V' }, 197 { "bind", 1, 0, 'b' }, 198 { "port", 1, 0, 'p' }, 199 { "socket", 1, 0, 'k' }, 200 { "offset", 1, 0, 'o' }, 201 { "read-only", 0, 0, 'r' }, 202 { "partition", 1, 0, 'P' }, 203 { "connect", 1, 0, 'c' }, 204 { "disconnect", 0, 0, 'd' }, 205 { "snapshot", 0, 0, 's' }, 206 { "nocache", 0, 0, 'n' }, 207 { "shared", 1, 0, 'e' }, 208 { "persistent", 0, 0, 't' }, 209 { "verbose", 0, 0, 'v' }, 210 { NULL, 0, 0, 0 } 211 }; 212 int ch; 213 int opt_ind = 0; 214 int li; 215 char *end; 216 int flags = 0; 217 int partition = -1; 218 int ret; 219 int shared = 1; 220 uint8_t *data; 221 fd_set fds; 222 int *sharing_fds; 223 int fd; 224 int i; 225 int nb_fds = 0; 226 int max_fd; 227 int persistent = 0; 228 229 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { 230 switch (ch) { 231 case 's': 232 flags |= BDRV_O_SNAPSHOT; 233 break; 234 case 'n': 235 flags |= BDRV_O_DIRECT; 236 break; 237 case 'b': 238 bindto = optarg; 239 break; 240 case 'p': 241 li = strtol(optarg, &end, 0); 242 if (*end) { 243 errx(EINVAL, "Invalid port `%s'", optarg); 244 } 245 if (li < 1 || li > 65535) { 246 errx(EINVAL, "Port out of range `%s'", optarg); 247 } 248 port = (uint16_t)li; 249 break; 250 case 'o': 251 dev_offset = strtoll (optarg, &end, 0); 252 if (*end) { 253 errx(EINVAL, "Invalid offset `%s'", optarg); 254 } 255 if (dev_offset < 0) { 256 errx(EINVAL, "Offset must be positive `%s'", optarg); 257 } 258 break; 259 case 'r': 260 readonly = true; 261 break; 262 case 'P': 263 partition = strtol(optarg, &end, 0); 264 if (*end) 265 errx(EINVAL, "Invalid partition `%s'", optarg); 266 if (partition < 1 || partition > 8) 267 errx(EINVAL, "Invalid partition %d", partition); 268 break; 269 case 'k': 270 socket = optarg; 271 if (socket[0] != '/') 272 errx(EINVAL, "socket path must be absolute\n"); 273 break; 274 case 'd': 275 disconnect = true; 276 break; 277 case 'c': 278 device = optarg; 279 break; 280 case 'e': 281 shared = strtol(optarg, &end, 0); 282 if (*end) { 283 errx(EINVAL, "Invalid shared device number '%s'", optarg); 284 } 285 if (shared < 1) { 286 errx(EINVAL, "Shared device number must be greater than 0\n"); 287 } 288 break; 289 case 't': 290 persistent = 1; 291 break; 292 case 'v': 293 verbose = 1; 294 break; 295 case 'V': 296 version(argv[0]); 297 exit(0); 298 break; 299 case 'h': 300 usage(argv[0]); 301 exit(0); 302 break; 303 case '?': 304 errx(EINVAL, "Try `%s --help' for more information.", 305 argv[0]); 306 } 307 } 308 309 if ((argc - optind) != 1) { 310 errx(EINVAL, "Invalid number of argument.\n" 311 "Try `%s --help' for more information.", 312 argv[0]); 313 } 314 315 if (disconnect) { 316 fd = open(argv[optind], O_RDWR); 317 if (fd == -1) 318 errx(errno, "Cannot open %s", argv[optind]); 319 320 nbd_disconnect(fd); 321 322 close(fd); 323 324 printf("%s disconnected\n", argv[optind]); 325 326 return 0; 327 } 328 329 bdrv_init(); 330 331 bs = bdrv_new("hda"); 332 if (bs == NULL) 333 return 1; 334 335 if (bdrv_open(bs, argv[optind], flags) == -1) 336 return 1; 337 338 fd_size = bs->total_sectors * 512; 339 340 if (partition != -1 && 341 find_partition(bs, partition, &dev_offset, &fd_size)) 342 errx(errno, "Could not find partition %d", partition); 343 344 if (device) { 345 pid_t pid; 346 int sock; 347 348 if (!verbose) 349 daemon(0, 0); /* detach client and server */ 350 351 if (socket == NULL) { 352 sprintf(sockpath, SOCKET_PATH, basename(device)); 353 socket = sockpath; 354 } 355 356 pid = fork(); 357 if (pid < 0) 358 return 1; 359 if (pid != 0) { 360 off_t size; 361 size_t blocksize; 362 363 ret = 0; 364 bdrv_close(bs); 365 366 do { 367 sock = unix_socket_outgoing(socket); 368 if (sock == -1) { 369 if (errno != ENOENT && errno != ECONNREFUSED) 370 goto out; 371 sleep(1); /* wait children */ 372 } 373 } while (sock == -1); 374 375 fd = open(device, O_RDWR); 376 if (fd == -1) { 377 ret = 1; 378 goto out; 379 } 380 381 ret = nbd_receive_negotiate(sock, &size, &blocksize); 382 if (ret == -1) { 383 ret = 1; 384 goto out; 385 } 386 387 ret = nbd_init(fd, sock, size, blocksize); 388 if (ret == -1) { 389 ret = 1; 390 goto out; 391 } 392 393 printf("NBD device %s is now connected to file %s\n", 394 device, argv[optind]); 395 396 /* update partition table */ 397 398 show_parts(device); 399 400 nbd_client(fd, sock); 401 close(fd); 402 out: 403 kill(pid, SIGTERM); 404 unlink(socket); 405 406 return ret; 407 } 408 /* children */ 409 } 410 411 sharing_fds = qemu_malloc((shared + 1) * sizeof(int)); 412 if (sharing_fds == NULL) 413 errx(ENOMEM, "Cannot allocate sharing fds"); 414 415 if (socket) { 416 sharing_fds[0] = unix_socket_incoming(socket); 417 } else { 418 sharing_fds[0] = tcp_socket_incoming(bindto, port); 419 } 420 421 if (sharing_fds[0] == -1) 422 return 1; 423 max_fd = sharing_fds[0]; 424 nb_fds++; 425 426 data = qemu_memalign(512, NBD_BUFFER_SIZE); 427 if (data == NULL) 428 errx(ENOMEM, "Cannot allocate data buffer"); 429 430 do { 431 432 FD_ZERO(&fds); 433 for (i = 0; i < nb_fds; i++) 434 FD_SET(sharing_fds[i], &fds); 435 436 ret = select(max_fd + 1, &fds, NULL, NULL, NULL); 437 if (ret == -1) 438 break; 439 440 if (FD_ISSET(sharing_fds[0], &fds)) 441 ret--; 442 for (i = 1; i < nb_fds && ret; i++) { 443 if (FD_ISSET(sharing_fds[i], &fds)) { 444 if (nbd_trip(bs, sharing_fds[i], fd_size, dev_offset, 445 &offset, readonly, data, NBD_BUFFER_SIZE) != 0) { 446 close(sharing_fds[i]); 447 nb_fds--; 448 sharing_fds[i] = sharing_fds[nb_fds]; 449 i--; 450 } 451 ret--; 452 } 453 } 454 /* new connection ? */ 455 if (FD_ISSET(sharing_fds[0], &fds)) { 456 if (nb_fds < shared + 1) { 457 sharing_fds[nb_fds] = accept(sharing_fds[0], 458 (struct sockaddr *)&addr, 459 &addr_len); 460 if (sharing_fds[nb_fds] != -1 && 461 nbd_negotiate(bs, sharing_fds[nb_fds], fd_size) != -1) { 462 if (sharing_fds[nb_fds] > max_fd) 463 max_fd = sharing_fds[nb_fds]; 464 nb_fds++; 465 } 466 } 467 } 468 } while (persistent || nb_fds > 1); 469 qemu_free(data); 470 471 close(sharing_fds[0]); 472 bdrv_close(bs); 473 qemu_free(sharing_fds); 474 if (socket) 475 unlink(socket); 476 477 return 0; 478 } 479