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/block.h" 21 #include "block/nbd.h" 22 #include "qemu/main-loop.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 #include <libgen.h> 35 #include <pthread.h> 36 37 #define SOCKET_PATH "/var/lock/qemu-nbd-%s" 38 #define QEMU_NBD_OPT_CACHE 1 39 #define QEMU_NBD_OPT_AIO 2 40 #define QEMU_NBD_OPT_DISCARD 3 41 42 static NBDExport *exp; 43 static int verbose; 44 static char *srcpath; 45 static char *sockpath; 46 static int persistent = 0; 47 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state; 48 static int shared = 1; 49 static int nb_fds; 50 51 static void usage(const char *name) 52 { 53 (printf) ( 54 "Usage: %s [OPTIONS] FILE\n" 55 "QEMU Disk Network Block Device Server\n" 56 "\n" 57 " -h, --help display this help and exit\n" 58 " -V, --version output version information and exit\n" 59 "\n" 60 "Connection properties:\n" 61 " -p, --port=PORT port to listen on (default `%d')\n" 62 " -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n" 63 " -k, --socket=PATH path to the unix socket\n" 64 " (default '"SOCKET_PATH"')\n" 65 " -e, --shared=NUM device can be shared by NUM clients (default '1')\n" 66 " -t, --persistent don't exit on the last connection\n" 67 " -v, --verbose display extra debugging information\n" 68 "\n" 69 "Exposing part of the image:\n" 70 " -o, --offset=OFFSET offset into the image\n" 71 " -P, --partition=NUM only expose partition NUM\n" 72 "\n" 73 #ifdef __linux__ 74 "Kernel NBD client support:\n" 75 " -c, --connect=DEV connect FILE to the local NBD device DEV\n" 76 " -d, --disconnect disconnect the specified device\n" 77 "\n" 78 #endif 79 "\n" 80 "Block device options:\n" 81 " -r, --read-only export read-only\n" 82 " -s, --snapshot use snapshot file\n" 83 " -n, --nocache disable host cache\n" 84 " --cache=MODE set cache mode (none, writeback, ...)\n" 85 #ifdef CONFIG_LINUX_AIO 86 " --aio=MODE set AIO mode (native or threads)\n" 87 #endif 88 "\n" 89 "Report bugs to <qemu-devel@nongnu.org>\n" 90 , name, NBD_DEFAULT_PORT, "DEVICE"); 91 } 92 93 static void version(const char *name) 94 { 95 printf( 96 "%s version 0.0.1\n" 97 "Written by Anthony Liguori.\n" 98 "\n" 99 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n" 100 "This is free software; see the source for copying conditions. There is NO\n" 101 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n" 102 , name); 103 } 104 105 struct partition_record 106 { 107 uint8_t bootable; 108 uint8_t start_head; 109 uint32_t start_cylinder; 110 uint8_t start_sector; 111 uint8_t system; 112 uint8_t end_head; 113 uint8_t end_cylinder; 114 uint8_t end_sector; 115 uint32_t start_sector_abs; 116 uint32_t nb_sectors_abs; 117 }; 118 119 static void read_partition(uint8_t *p, struct partition_record *r) 120 { 121 r->bootable = p[0]; 122 r->start_head = p[1]; 123 r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300); 124 r->start_sector = p[2] & 0x3f; 125 r->system = p[4]; 126 r->end_head = p[5]; 127 r->end_cylinder = p[7] | ((p[6] << 2) & 0x300); 128 r->end_sector = p[6] & 0x3f; 129 r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24; 130 r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24; 131 } 132 133 static int find_partition(BlockDriverState *bs, int partition, 134 off_t *offset, off_t *size) 135 { 136 struct partition_record mbr[4]; 137 uint8_t data[512]; 138 int i; 139 int ext_partnum = 4; 140 int ret; 141 142 if ((ret = bdrv_read(bs, 0, data, 1)) < 0) { 143 errno = -ret; 144 err(EXIT_FAILURE, "error while reading"); 145 } 146 147 if (data[510] != 0x55 || data[511] != 0xaa) { 148 return -EINVAL; 149 } 150 151 for (i = 0; i < 4; i++) { 152 read_partition(&data[446 + 16 * i], &mbr[i]); 153 154 if (!mbr[i].nb_sectors_abs) 155 continue; 156 157 if (mbr[i].system == 0xF || mbr[i].system == 0x5) { 158 struct partition_record ext[4]; 159 uint8_t data1[512]; 160 int j; 161 162 if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) { 163 errno = -ret; 164 err(EXIT_FAILURE, "error while reading"); 165 } 166 167 for (j = 0; j < 4; j++) { 168 read_partition(&data1[446 + 16 * j], &ext[j]); 169 if (!ext[j].nb_sectors_abs) 170 continue; 171 172 if ((ext_partnum + j + 1) == partition) { 173 *offset = (uint64_t)ext[j].start_sector_abs << 9; 174 *size = (uint64_t)ext[j].nb_sectors_abs << 9; 175 return 0; 176 } 177 } 178 ext_partnum += 4; 179 } else if ((i + 1) == partition) { 180 *offset = (uint64_t)mbr[i].start_sector_abs << 9; 181 *size = (uint64_t)mbr[i].nb_sectors_abs << 9; 182 return 0; 183 } 184 } 185 186 return -ENOENT; 187 } 188 189 static void termsig_handler(int signum) 190 { 191 state = TERMINATE; 192 qemu_notify_event(); 193 } 194 195 static void *show_parts(void *arg) 196 { 197 char *device = arg; 198 int nbd; 199 200 /* linux just needs an open() to trigger 201 * the partition table update 202 * but remember to load the module with max_part != 0 : 203 * modprobe nbd max_part=63 204 */ 205 nbd = open(device, O_RDWR); 206 if (nbd >= 0) { 207 close(nbd); 208 } 209 return NULL; 210 } 211 212 static void *nbd_client_thread(void *arg) 213 { 214 char *device = arg; 215 off_t size; 216 size_t blocksize; 217 uint32_t nbdflags; 218 int fd, sock; 219 int ret; 220 pthread_t show_parts_thread; 221 222 sock = unix_socket_outgoing(sockpath); 223 if (sock < 0) { 224 goto out; 225 } 226 227 ret = nbd_receive_negotiate(sock, NULL, &nbdflags, 228 &size, &blocksize); 229 if (ret < 0) { 230 goto out; 231 } 232 233 fd = open(device, O_RDWR); 234 if (fd < 0) { 235 /* Linux-only, we can use %m in printf. */ 236 fprintf(stderr, "Failed to open %s: %m", device); 237 goto out; 238 } 239 240 ret = nbd_init(fd, sock, nbdflags, size, blocksize); 241 if (ret < 0) { 242 goto out; 243 } 244 245 /* update partition table */ 246 pthread_create(&show_parts_thread, NULL, show_parts, device); 247 248 if (verbose) { 249 fprintf(stderr, "NBD device %s is now connected to %s\n", 250 device, srcpath); 251 } else { 252 /* Close stderr so that the qemu-nbd process exits. */ 253 dup2(STDOUT_FILENO, STDERR_FILENO); 254 } 255 256 ret = nbd_client(fd); 257 if (ret) { 258 goto out; 259 } 260 close(fd); 261 kill(getpid(), SIGTERM); 262 return (void *) EXIT_SUCCESS; 263 264 out: 265 kill(getpid(), SIGTERM); 266 return (void *) EXIT_FAILURE; 267 } 268 269 static int nbd_can_accept(void *opaque) 270 { 271 return nb_fds < shared; 272 } 273 274 static void nbd_export_closed(NBDExport *exp) 275 { 276 assert(state == TERMINATING); 277 state = TERMINATED; 278 } 279 280 static void nbd_client_closed(NBDClient *client) 281 { 282 nb_fds--; 283 if (nb_fds == 0 && !persistent && state == RUNNING) { 284 state = TERMINATE; 285 } 286 qemu_notify_event(); 287 nbd_client_put(client); 288 } 289 290 static void nbd_accept(void *opaque) 291 { 292 int server_fd = (uintptr_t) opaque; 293 struct sockaddr_in addr; 294 socklen_t addr_len = sizeof(addr); 295 296 int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len); 297 if (state >= TERMINATE) { 298 close(fd); 299 return; 300 } 301 302 if (fd >= 0 && nbd_client_new(exp, fd, nbd_client_closed)) { 303 nb_fds++; 304 } 305 } 306 307 int main(int argc, char **argv) 308 { 309 BlockDriverState *bs; 310 BlockDriver *drv; 311 off_t dev_offset = 0; 312 uint32_t nbdflags = 0; 313 bool disconnect = false; 314 const char *bindto = "0.0.0.0"; 315 char *device = NULL; 316 int port = NBD_DEFAULT_PORT; 317 off_t fd_size; 318 const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:t"; 319 struct option lopt[] = { 320 { "help", 0, NULL, 'h' }, 321 { "version", 0, NULL, 'V' }, 322 { "bind", 1, NULL, 'b' }, 323 { "port", 1, NULL, 'p' }, 324 { "socket", 1, NULL, 'k' }, 325 { "offset", 1, NULL, 'o' }, 326 { "read-only", 0, NULL, 'r' }, 327 { "partition", 1, NULL, 'P' }, 328 { "connect", 1, NULL, 'c' }, 329 { "disconnect", 0, NULL, 'd' }, 330 { "snapshot", 0, NULL, 's' }, 331 { "nocache", 0, NULL, 'n' }, 332 { "cache", 1, NULL, QEMU_NBD_OPT_CACHE }, 333 #ifdef CONFIG_LINUX_AIO 334 { "aio", 1, NULL, QEMU_NBD_OPT_AIO }, 335 #endif 336 { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD }, 337 { "shared", 1, NULL, 'e' }, 338 { "format", 1, NULL, 'f' }, 339 { "persistent", 0, NULL, 't' }, 340 { "verbose", 0, NULL, 'v' }, 341 { NULL, 0, NULL, 0 } 342 }; 343 int ch; 344 int opt_ind = 0; 345 int li; 346 char *end; 347 int flags = BDRV_O_RDWR; 348 int partition = -1; 349 int ret; 350 int fd; 351 bool seen_cache = false; 352 bool seen_discard = false; 353 #ifdef CONFIG_LINUX_AIO 354 bool seen_aio = false; 355 #endif 356 pthread_t client_thread; 357 const char *fmt = NULL; 358 359 /* The client thread uses SIGTERM to interrupt the server. A signal 360 * handler ensures that "qemu-nbd -v -c" exits with a nice status code. 361 */ 362 struct sigaction sa_sigterm; 363 memset(&sa_sigterm, 0, sizeof(sa_sigterm)); 364 sa_sigterm.sa_handler = termsig_handler; 365 sigaction(SIGTERM, &sa_sigterm, NULL); 366 367 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { 368 switch (ch) { 369 case 's': 370 flags |= BDRV_O_SNAPSHOT; 371 break; 372 case 'n': 373 optarg = (char *) "none"; 374 /* fallthrough */ 375 case QEMU_NBD_OPT_CACHE: 376 if (seen_cache) { 377 errx(EXIT_FAILURE, "-n and --cache can only be specified once"); 378 } 379 seen_cache = true; 380 if (bdrv_parse_cache_flags(optarg, &flags) == -1) { 381 errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg); 382 } 383 break; 384 #ifdef CONFIG_LINUX_AIO 385 case QEMU_NBD_OPT_AIO: 386 if (seen_aio) { 387 errx(EXIT_FAILURE, "--aio can only be specified once"); 388 } 389 seen_aio = true; 390 if (!strcmp(optarg, "native")) { 391 flags |= BDRV_O_NATIVE_AIO; 392 } else if (!strcmp(optarg, "threads")) { 393 /* this is the default */ 394 } else { 395 errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg); 396 } 397 break; 398 #endif 399 case QEMU_NBD_OPT_DISCARD: 400 if (seen_discard) { 401 errx(EXIT_FAILURE, "--discard can only be specified once"); 402 } 403 seen_discard = true; 404 if (bdrv_parse_discard_flags(optarg, &flags) == -1) { 405 errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg); 406 } 407 break; 408 case 'b': 409 bindto = optarg; 410 break; 411 case 'p': 412 li = strtol(optarg, &end, 0); 413 if (*end) { 414 errx(EXIT_FAILURE, "Invalid port `%s'", optarg); 415 } 416 if (li < 1 || li > 65535) { 417 errx(EXIT_FAILURE, "Port out of range `%s'", optarg); 418 } 419 port = (uint16_t)li; 420 break; 421 case 'o': 422 dev_offset = strtoll (optarg, &end, 0); 423 if (*end) { 424 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg); 425 } 426 if (dev_offset < 0) { 427 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg); 428 } 429 break; 430 case 'r': 431 nbdflags |= NBD_FLAG_READ_ONLY; 432 flags &= ~BDRV_O_RDWR; 433 break; 434 case 'P': 435 partition = strtol(optarg, &end, 0); 436 if (*end) 437 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg); 438 if (partition < 1 || partition > 8) 439 errx(EXIT_FAILURE, "Invalid partition %d", partition); 440 break; 441 case 'k': 442 sockpath = optarg; 443 if (sockpath[0] != '/') 444 errx(EXIT_FAILURE, "socket path must be absolute\n"); 445 break; 446 case 'd': 447 disconnect = true; 448 break; 449 case 'c': 450 device = optarg; 451 break; 452 case 'e': 453 shared = strtol(optarg, &end, 0); 454 if (*end) { 455 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg); 456 } 457 if (shared < 1) { 458 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n"); 459 } 460 break; 461 case 'f': 462 fmt = optarg; 463 break; 464 case 't': 465 persistent = 1; 466 break; 467 case 'v': 468 verbose = 1; 469 break; 470 case 'V': 471 version(argv[0]); 472 exit(0); 473 break; 474 case 'h': 475 usage(argv[0]); 476 exit(0); 477 break; 478 case '?': 479 errx(EXIT_FAILURE, "Try `%s --help' for more information.", 480 argv[0]); 481 } 482 } 483 484 if ((argc - optind) != 1) { 485 errx(EXIT_FAILURE, "Invalid number of argument.\n" 486 "Try `%s --help' for more information.", 487 argv[0]); 488 } 489 490 if (disconnect) { 491 fd = open(argv[optind], O_RDWR); 492 if (fd < 0) { 493 err(EXIT_FAILURE, "Cannot open %s", argv[optind]); 494 } 495 nbd_disconnect(fd); 496 497 close(fd); 498 499 printf("%s disconnected\n", argv[optind]); 500 501 return 0; 502 } 503 504 if (device && !verbose) { 505 int stderr_fd[2]; 506 pid_t pid; 507 int ret; 508 509 if (qemu_pipe(stderr_fd) < 0) { 510 err(EXIT_FAILURE, "Error setting up communication pipe"); 511 } 512 513 /* Now daemonize, but keep a communication channel open to 514 * print errors and exit with the proper status code. 515 */ 516 pid = fork(); 517 if (pid == 0) { 518 close(stderr_fd[0]); 519 ret = qemu_daemon(1, 0); 520 521 /* Temporarily redirect stderr to the parent's pipe... */ 522 dup2(stderr_fd[1], STDERR_FILENO); 523 if (ret < 0) { 524 err(EXIT_FAILURE, "Failed to daemonize"); 525 } 526 527 /* ... close the descriptor we inherited and go on. */ 528 close(stderr_fd[1]); 529 } else { 530 bool errors = false; 531 char *buf; 532 533 /* In the parent. Print error messages from the child until 534 * it closes the pipe. 535 */ 536 close(stderr_fd[1]); 537 buf = g_malloc(1024); 538 while ((ret = read(stderr_fd[0], buf, 1024)) > 0) { 539 errors = true; 540 ret = qemu_write_full(STDERR_FILENO, buf, ret); 541 if (ret < 0) { 542 exit(EXIT_FAILURE); 543 } 544 } 545 if (ret < 0) { 546 err(EXIT_FAILURE, "Cannot read from daemon"); 547 } 548 549 /* Usually the daemon should not print any message. 550 * Exit with zero status in that case. 551 */ 552 exit(errors); 553 } 554 } 555 556 if (device != NULL && sockpath == NULL) { 557 sockpath = g_malloc(128); 558 snprintf(sockpath, 128, SOCKET_PATH, basename(device)); 559 } 560 561 qemu_init_main_loop(); 562 bdrv_init(); 563 atexit(bdrv_close_all); 564 565 if (fmt) { 566 drv = bdrv_find_format(fmt); 567 if (!drv) { 568 errx(EXIT_FAILURE, "Unknown file format '%s'", fmt); 569 } 570 } else { 571 drv = NULL; 572 } 573 574 bs = bdrv_new("hda"); 575 srcpath = argv[optind]; 576 ret = bdrv_open(bs, srcpath, NULL, flags, drv); 577 if (ret < 0) { 578 errno = -ret; 579 err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]); 580 } 581 582 fd_size = bdrv_getlength(bs); 583 584 if (partition != -1) { 585 ret = find_partition(bs, partition, &dev_offset, &fd_size); 586 if (ret < 0) { 587 errno = -ret; 588 err(EXIT_FAILURE, "Could not find partition %d", partition); 589 } 590 } 591 592 exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed); 593 594 if (sockpath) { 595 fd = unix_socket_incoming(sockpath); 596 } else { 597 fd = tcp_socket_incoming(bindto, port); 598 } 599 600 if (fd < 0) { 601 return 1; 602 } 603 604 if (device) { 605 int ret; 606 607 ret = pthread_create(&client_thread, NULL, nbd_client_thread, device); 608 if (ret != 0) { 609 errx(EXIT_FAILURE, "Failed to create client thread: %s", 610 strerror(ret)); 611 } 612 } else { 613 /* Shut up GCC warnings. */ 614 memset(&client_thread, 0, sizeof(client_thread)); 615 } 616 617 qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL, 618 (void *)(uintptr_t)fd); 619 620 /* now when the initialization is (almost) complete, chdir("/") 621 * to free any busy filesystems */ 622 if (chdir("/") < 0) { 623 err(EXIT_FAILURE, "Could not chdir to root directory"); 624 } 625 626 state = RUNNING; 627 do { 628 main_loop_wait(false); 629 if (state == TERMINATE) { 630 state = TERMINATING; 631 nbd_export_close(exp); 632 nbd_export_put(exp); 633 exp = NULL; 634 } 635 } while (state != TERMINATED); 636 637 bdrv_close(bs); 638 if (sockpath) { 639 unlink(sockpath); 640 } 641 642 if (device) { 643 void *ret; 644 pthread_join(client_thread, &ret); 645 exit(ret != NULL); 646 } else { 647 exit(EXIT_SUCCESS); 648 } 649 } 650