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 #include <pthread.h> 35 36 #define SOCKET_PATH "/var/lock/qemu-nbd-%s" 37 38 #define NBD_BUFFER_SIZE (1024*1024) 39 40 static int sigterm_wfd; 41 static int verbose; 42 static char *device; 43 static char *srcpath; 44 static char *sockpath; 45 46 static void usage(const char *name) 47 { 48 printf( 49 "Usage: %s [OPTIONS] FILE\n" 50 "QEMU Disk Network Block Device Server\n" 51 "\n" 52 " -p, --port=PORT port to listen on (default `%d')\n" 53 " -o, --offset=OFFSET offset into the image\n" 54 " -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n" 55 " -k, --socket=PATH path to the unix socket\n" 56 " (default '"SOCKET_PATH"')\n" 57 " -r, --read-only export read-only\n" 58 " -P, --partition=NUM only expose partition NUM\n" 59 " -s, --snapshot use snapshot file\n" 60 " -n, --nocache disable host cache\n" 61 " -c, --connect=DEV connect FILE to the local NBD device DEV\n" 62 " -d, --disconnect disconnect the specified device\n" 63 " -e, --shared=NUM device can be shared by NUM clients (default '1')\n" 64 " -t, --persistent don't exit on the last connection\n" 65 " -v, --verbose display extra debugging information\n" 66 " -h, --help display this help and exit\n" 67 " -V, --version output version information and exit\n" 68 "\n" 69 "Report bugs to <anthony@codemonkey.ws>\n" 70 , name, NBD_DEFAULT_PORT, "DEVICE"); 71 } 72 73 static void version(const char *name) 74 { 75 printf( 76 "%s version 0.0.1\n" 77 "Written by Anthony Liguori.\n" 78 "\n" 79 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n" 80 "This is free software; see the source for copying conditions. There is NO\n" 81 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n" 82 , name); 83 } 84 85 struct partition_record 86 { 87 uint8_t bootable; 88 uint8_t start_head; 89 uint32_t start_cylinder; 90 uint8_t start_sector; 91 uint8_t system; 92 uint8_t end_head; 93 uint8_t end_cylinder; 94 uint8_t end_sector; 95 uint32_t start_sector_abs; 96 uint32_t nb_sectors_abs; 97 }; 98 99 static void read_partition(uint8_t *p, struct partition_record *r) 100 { 101 r->bootable = p[0]; 102 r->start_head = p[1]; 103 r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300); 104 r->start_sector = p[2] & 0x3f; 105 r->system = p[4]; 106 r->end_head = p[5]; 107 r->end_cylinder = p[7] | ((p[6] << 2) & 0x300); 108 r->end_sector = p[6] & 0x3f; 109 r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24; 110 r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24; 111 } 112 113 static int find_partition(BlockDriverState *bs, int partition, 114 off_t *offset, off_t *size) 115 { 116 struct partition_record mbr[4]; 117 uint8_t data[512]; 118 int i; 119 int ext_partnum = 4; 120 int ret; 121 122 if ((ret = bdrv_read(bs, 0, data, 1)) < 0) { 123 errno = -ret; 124 err(EXIT_FAILURE, "error while reading"); 125 } 126 127 if (data[510] != 0x55 || data[511] != 0xaa) { 128 errno = -EINVAL; 129 return -1; 130 } 131 132 for (i = 0; i < 4; i++) { 133 read_partition(&data[446 + 16 * i], &mbr[i]); 134 135 if (!mbr[i].nb_sectors_abs) 136 continue; 137 138 if (mbr[i].system == 0xF || mbr[i].system == 0x5) { 139 struct partition_record ext[4]; 140 uint8_t data1[512]; 141 int j; 142 143 if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) { 144 errno = -ret; 145 err(EXIT_FAILURE, "error while reading"); 146 } 147 148 for (j = 0; j < 4; j++) { 149 read_partition(&data1[446 + 16 * j], &ext[j]); 150 if (!ext[j].nb_sectors_abs) 151 continue; 152 153 if ((ext_partnum + j + 1) == partition) { 154 *offset = (uint64_t)ext[j].start_sector_abs << 9; 155 *size = (uint64_t)ext[j].nb_sectors_abs << 9; 156 return 0; 157 } 158 } 159 ext_partnum += 4; 160 } else if ((i + 1) == partition) { 161 *offset = (uint64_t)mbr[i].start_sector_abs << 9; 162 *size = (uint64_t)mbr[i].nb_sectors_abs << 9; 163 return 0; 164 } 165 } 166 167 errno = -ENOENT; 168 return -1; 169 } 170 171 static void termsig_handler(int signum) 172 { 173 static int sigterm_reported; 174 if (!sigterm_reported) { 175 sigterm_reported = (write(sigterm_wfd, "", 1) == 1); 176 } 177 } 178 179 static void *show_parts(void *arg) 180 { 181 int nbd; 182 183 /* linux just needs an open() to trigger 184 * the partition table update 185 * but remember to load the module with max_part != 0 : 186 * modprobe nbd max_part=63 187 */ 188 nbd = open(device, O_RDWR); 189 if (nbd != -1) { 190 close(nbd); 191 } 192 return NULL; 193 } 194 195 static void *nbd_client_thread(void *arg) 196 { 197 int fd = *(int *)arg; 198 off_t size; 199 size_t blocksize; 200 uint32_t nbdflags; 201 int sock; 202 int ret; 203 pthread_t show_parts_thread; 204 205 do { 206 sock = unix_socket_outgoing(sockpath); 207 if (sock == -1) { 208 goto out; 209 } 210 } while (sock == -1); 211 212 ret = nbd_receive_negotiate(sock, NULL, &nbdflags, 213 &size, &blocksize); 214 if (ret == -1) { 215 goto out; 216 } 217 218 ret = nbd_init(fd, sock, nbdflags, size, blocksize); 219 if (ret == -1) { 220 goto out; 221 } 222 223 /* update partition table */ 224 pthread_create(&show_parts_thread, NULL, show_parts, NULL); 225 226 if (verbose) { 227 fprintf(stderr, "NBD device %s is now connected to %s\n", 228 device, srcpath); 229 } else { 230 /* Close stderr so that the qemu-nbd process exits. */ 231 dup2(STDOUT_FILENO, STDERR_FILENO); 232 } 233 234 ret = nbd_client(fd); 235 if (ret) { 236 goto out; 237 } 238 close(fd); 239 kill(getpid(), SIGTERM); 240 return (void *) EXIT_SUCCESS; 241 242 out: 243 kill(getpid(), SIGTERM); 244 return (void *) EXIT_FAILURE; 245 } 246 247 int main(int argc, char **argv) 248 { 249 BlockDriverState *bs; 250 off_t dev_offset = 0; 251 off_t offset = 0; 252 uint32_t nbdflags = 0; 253 bool disconnect = false; 254 const char *bindto = "0.0.0.0"; 255 int port = NBD_DEFAULT_PORT; 256 struct sockaddr_in addr; 257 socklen_t addr_len = sizeof(addr); 258 off_t fd_size; 259 const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t"; 260 struct option lopt[] = { 261 { "help", 0, NULL, 'h' }, 262 { "version", 0, NULL, 'V' }, 263 { "bind", 1, NULL, 'b' }, 264 { "port", 1, NULL, 'p' }, 265 { "socket", 1, NULL, 'k' }, 266 { "offset", 1, NULL, 'o' }, 267 { "read-only", 0, NULL, 'r' }, 268 { "partition", 1, NULL, 'P' }, 269 { "connect", 1, NULL, 'c' }, 270 { "disconnect", 0, NULL, 'd' }, 271 { "snapshot", 0, NULL, 's' }, 272 { "nocache", 0, NULL, 'n' }, 273 { "shared", 1, NULL, 'e' }, 274 { "persistent", 0, NULL, 't' }, 275 { "verbose", 0, NULL, 'v' }, 276 { NULL, 0, NULL, 0 } 277 }; 278 int ch; 279 int opt_ind = 0; 280 int li; 281 char *end; 282 int flags = BDRV_O_RDWR; 283 int partition = -1; 284 int ret; 285 int shared = 1; 286 uint8_t *data; 287 fd_set fds; 288 int *sharing_fds; 289 int fd; 290 int i; 291 int nb_fds = 0; 292 int max_fd; 293 int persistent = 0; 294 pthread_t client_thread; 295 296 /* The client thread uses SIGTERM to interrupt the server. A signal 297 * handler ensures that "qemu-nbd -v -c" exits with a nice status code. 298 */ 299 struct sigaction sa_sigterm; 300 int sigterm_fd[2]; 301 if (qemu_pipe(sigterm_fd) == -1) { 302 err(EXIT_FAILURE, "Error setting up communication pipe"); 303 } 304 305 sigterm_wfd = sigterm_fd[1]; 306 memset(&sa_sigterm, 0, sizeof(sa_sigterm)); 307 sa_sigterm.sa_handler = termsig_handler; 308 sigaction(SIGTERM, &sa_sigterm, NULL); 309 310 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { 311 switch (ch) { 312 case 's': 313 flags |= BDRV_O_SNAPSHOT; 314 break; 315 case 'n': 316 flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; 317 break; 318 case 'b': 319 bindto = optarg; 320 break; 321 case 'p': 322 li = strtol(optarg, &end, 0); 323 if (*end) { 324 errx(EXIT_FAILURE, "Invalid port `%s'", optarg); 325 } 326 if (li < 1 || li > 65535) { 327 errx(EXIT_FAILURE, "Port out of range `%s'", optarg); 328 } 329 port = (uint16_t)li; 330 break; 331 case 'o': 332 dev_offset = strtoll (optarg, &end, 0); 333 if (*end) { 334 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg); 335 } 336 if (dev_offset < 0) { 337 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg); 338 } 339 break; 340 case 'r': 341 nbdflags |= NBD_FLAG_READ_ONLY; 342 flags &= ~BDRV_O_RDWR; 343 break; 344 case 'P': 345 partition = strtol(optarg, &end, 0); 346 if (*end) 347 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg); 348 if (partition < 1 || partition > 8) 349 errx(EXIT_FAILURE, "Invalid partition %d", partition); 350 break; 351 case 'k': 352 sockpath = optarg; 353 if (sockpath[0] != '/') 354 errx(EXIT_FAILURE, "socket path must be absolute\n"); 355 break; 356 case 'd': 357 disconnect = true; 358 break; 359 case 'c': 360 device = optarg; 361 break; 362 case 'e': 363 shared = strtol(optarg, &end, 0); 364 if (*end) { 365 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg); 366 } 367 if (shared < 1) { 368 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n"); 369 } 370 break; 371 case 't': 372 persistent = 1; 373 break; 374 case 'v': 375 verbose = 1; 376 break; 377 case 'V': 378 version(argv[0]); 379 exit(0); 380 break; 381 case 'h': 382 usage(argv[0]); 383 exit(0); 384 break; 385 case '?': 386 errx(EXIT_FAILURE, "Try `%s --help' for more information.", 387 argv[0]); 388 } 389 } 390 391 if ((argc - optind) != 1) { 392 errx(EXIT_FAILURE, "Invalid number of argument.\n" 393 "Try `%s --help' for more information.", 394 argv[0]); 395 } 396 397 if (disconnect) { 398 fd = open(argv[optind], O_RDWR); 399 if (fd == -1) 400 err(EXIT_FAILURE, "Cannot open %s", argv[optind]); 401 402 nbd_disconnect(fd); 403 404 close(fd); 405 406 printf("%s disconnected\n", argv[optind]); 407 408 return 0; 409 } 410 411 if (device && !verbose) { 412 int stderr_fd[2]; 413 pid_t pid; 414 int ret; 415 416 if (qemu_pipe(stderr_fd) == -1) { 417 err(EXIT_FAILURE, "Error setting up communication pipe"); 418 } 419 420 /* Now daemonize, but keep a communication channel open to 421 * print errors and exit with the proper status code. 422 */ 423 pid = fork(); 424 if (pid == 0) { 425 close(stderr_fd[0]); 426 ret = qemu_daemon(0, 0); 427 428 /* Temporarily redirect stderr to the parent's pipe... */ 429 dup2(stderr_fd[1], STDERR_FILENO); 430 if (ret == -1) { 431 err(EXIT_FAILURE, "Failed to daemonize"); 432 } 433 434 /* ... close the descriptor we inherited and go on. */ 435 close(stderr_fd[1]); 436 } else { 437 bool errors = false; 438 char *buf; 439 440 /* In the parent. Print error messages from the child until 441 * it closes the pipe. 442 */ 443 close(stderr_fd[1]); 444 buf = g_malloc(1024); 445 while ((ret = read(stderr_fd[0], buf, 1024)) > 0) { 446 errors = true; 447 ret = qemu_write_full(STDERR_FILENO, buf, ret); 448 if (ret == -1) { 449 exit(EXIT_FAILURE); 450 } 451 } 452 if (ret == -1) { 453 err(EXIT_FAILURE, "Cannot read from daemon"); 454 } 455 456 /* Usually the daemon should not print any message. 457 * Exit with zero status in that case. 458 */ 459 exit(errors); 460 } 461 } 462 463 if (device) { 464 /* Open before spawning new threads. In the future, we may 465 * drop privileges after opening. 466 */ 467 fd = open(device, O_RDWR); 468 if (fd == -1) { 469 err(EXIT_FAILURE, "Failed to open %s", device); 470 } 471 472 if (sockpath == NULL) { 473 sockpath = g_malloc(128); 474 snprintf(sockpath, 128, SOCKET_PATH, basename(device)); 475 } 476 } 477 478 bdrv_init(); 479 atexit(bdrv_close_all); 480 481 bs = bdrv_new("hda"); 482 srcpath = argv[optind]; 483 if ((ret = bdrv_open(bs, srcpath, flags, NULL)) < 0) { 484 errno = -ret; 485 err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]); 486 } 487 488 fd_size = bs->total_sectors * 512; 489 490 if (partition != -1 && 491 find_partition(bs, partition, &dev_offset, &fd_size)) { 492 err(EXIT_FAILURE, "Could not find partition %d", partition); 493 } 494 495 sharing_fds = g_malloc((shared + 1) * sizeof(int)); 496 497 if (sockpath) { 498 sharing_fds[0] = unix_socket_incoming(sockpath); 499 } else { 500 sharing_fds[0] = tcp_socket_incoming(bindto, port); 501 } 502 503 if (sharing_fds[0] == -1) 504 return 1; 505 506 if (device) { 507 int ret; 508 509 ret = pthread_create(&client_thread, NULL, nbd_client_thread, &fd); 510 if (ret != 0) { 511 errx(EXIT_FAILURE, "Failed to create client thread: %s", 512 strerror(ret)); 513 } 514 } else { 515 /* Shut up GCC warnings. */ 516 memset(&client_thread, 0, sizeof(client_thread)); 517 } 518 519 max_fd = sharing_fds[0]; 520 nb_fds++; 521 522 data = qemu_blockalign(bs, NBD_BUFFER_SIZE); 523 if (data == NULL) { 524 errx(EXIT_FAILURE, "Cannot allocate data buffer"); 525 } 526 527 do { 528 FD_ZERO(&fds); 529 FD_SET(sigterm_fd[0], &fds); 530 for (i = 0; i < nb_fds; i++) 531 FD_SET(sharing_fds[i], &fds); 532 533 do { 534 ret = select(max_fd + 1, &fds, NULL, NULL, NULL); 535 } while (ret == -1 && errno == EINTR); 536 if (ret == -1 || FD_ISSET(sigterm_fd[0], &fds)) { 537 break; 538 } 539 540 if (FD_ISSET(sharing_fds[0], &fds)) 541 ret--; 542 for (i = 1; i < nb_fds && ret; i++) { 543 if (FD_ISSET(sharing_fds[i], &fds)) { 544 if (nbd_trip(bs, sharing_fds[i], fd_size, dev_offset, 545 &offset, nbdflags, data, NBD_BUFFER_SIZE) != 0) { 546 close(sharing_fds[i]); 547 nb_fds--; 548 sharing_fds[i] = sharing_fds[nb_fds]; 549 i--; 550 } 551 ret--; 552 } 553 } 554 /* new connection ? */ 555 if (FD_ISSET(sharing_fds[0], &fds)) { 556 if (nb_fds < shared + 1) { 557 sharing_fds[nb_fds] = accept(sharing_fds[0], 558 (struct sockaddr *)&addr, 559 &addr_len); 560 if (sharing_fds[nb_fds] != -1 && 561 nbd_negotiate(sharing_fds[nb_fds], fd_size, nbdflags) != -1) { 562 if (sharing_fds[nb_fds] > max_fd) 563 max_fd = sharing_fds[nb_fds]; 564 nb_fds++; 565 } 566 } 567 } 568 } while (persistent || nb_fds > 1); 569 qemu_vfree(data); 570 571 close(sharing_fds[0]); 572 g_free(sharing_fds); 573 if (sockpath) { 574 unlink(sockpath); 575 } 576 577 if (device) { 578 void *ret; 579 pthread_join(client_thread, &ret); 580 exit(ret != NULL); 581 } else { 582 exit(EXIT_SUCCESS); 583 } 584 } 585