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