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 static NBDExport *exp; 39 static int verbose; 40 static char *device; 41 static char *srcpath; 42 static char *sockpath; 43 static bool sigterm_reported; 44 static bool nbd_started; 45 static int shared = 1; 46 static int nb_fds; 47 48 static void usage(const char *name) 49 { 50 printf( 51 "Usage: %s [OPTIONS] FILE\n" 52 "QEMU Disk Network Block Device Server\n" 53 "\n" 54 " -p, --port=PORT port to listen on (default `%d')\n" 55 " -o, --offset=OFFSET offset into the image\n" 56 " -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n" 57 " -k, --socket=PATH path to the unix socket\n" 58 " (default '"SOCKET_PATH"')\n" 59 " -r, --read-only export read-only\n" 60 " -P, --partition=NUM only expose partition NUM\n" 61 " -s, --snapshot use snapshot file\n" 62 " -n, --nocache disable host cache\n" 63 " -c, --connect=DEV connect FILE to the local NBD device DEV\n" 64 " -d, --disconnect disconnect the specified device\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 " -h, --help display this help and exit\n" 69 " -V, --version output version information and exit\n" 70 "\n" 71 "Report bugs to <anthony@codemonkey.ws>\n" 72 , name, NBD_DEFAULT_PORT, "DEVICE"); 73 } 74 75 static void version(const char *name) 76 { 77 printf( 78 "%s version 0.0.1\n" 79 "Written by Anthony Liguori.\n" 80 "\n" 81 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n" 82 "This is free software; see the source for copying conditions. There is NO\n" 83 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n" 84 , name); 85 } 86 87 struct partition_record 88 { 89 uint8_t bootable; 90 uint8_t start_head; 91 uint32_t start_cylinder; 92 uint8_t start_sector; 93 uint8_t system; 94 uint8_t end_head; 95 uint8_t end_cylinder; 96 uint8_t end_sector; 97 uint32_t start_sector_abs; 98 uint32_t nb_sectors_abs; 99 }; 100 101 static void read_partition(uint8_t *p, struct partition_record *r) 102 { 103 r->bootable = p[0]; 104 r->start_head = p[1]; 105 r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300); 106 r->start_sector = p[2] & 0x3f; 107 r->system = p[4]; 108 r->end_head = p[5]; 109 r->end_cylinder = p[7] | ((p[6] << 2) & 0x300); 110 r->end_sector = p[6] & 0x3f; 111 r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24; 112 r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24; 113 } 114 115 static int find_partition(BlockDriverState *bs, int partition, 116 off_t *offset, off_t *size) 117 { 118 struct partition_record mbr[4]; 119 uint8_t data[512]; 120 int i; 121 int ext_partnum = 4; 122 int ret; 123 124 if ((ret = bdrv_read(bs, 0, data, 1)) < 0) { 125 errno = -ret; 126 err(EXIT_FAILURE, "error while reading"); 127 } 128 129 if (data[510] != 0x55 || data[511] != 0xaa) { 130 errno = -EINVAL; 131 return -1; 132 } 133 134 for (i = 0; i < 4; i++) { 135 read_partition(&data[446 + 16 * i], &mbr[i]); 136 137 if (!mbr[i].nb_sectors_abs) 138 continue; 139 140 if (mbr[i].system == 0xF || mbr[i].system == 0x5) { 141 struct partition_record ext[4]; 142 uint8_t data1[512]; 143 int j; 144 145 if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) { 146 errno = -ret; 147 err(EXIT_FAILURE, "error while reading"); 148 } 149 150 for (j = 0; j < 4; j++) { 151 read_partition(&data1[446 + 16 * j], &ext[j]); 152 if (!ext[j].nb_sectors_abs) 153 continue; 154 155 if ((ext_partnum + j + 1) == partition) { 156 *offset = (uint64_t)ext[j].start_sector_abs << 9; 157 *size = (uint64_t)ext[j].nb_sectors_abs << 9; 158 return 0; 159 } 160 } 161 ext_partnum += 4; 162 } else if ((i + 1) == partition) { 163 *offset = (uint64_t)mbr[i].start_sector_abs << 9; 164 *size = (uint64_t)mbr[i].nb_sectors_abs << 9; 165 return 0; 166 } 167 } 168 169 errno = -ENOENT; 170 return -1; 171 } 172 173 static void termsig_handler(int signum) 174 { 175 sigterm_reported = true; 176 qemu_notify_event(); 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 sock = unix_socket_outgoing(sockpath); 206 if (sock == -1) { 207 goto out; 208 } 209 210 ret = nbd_receive_negotiate(sock, NULL, &nbdflags, 211 &size, &blocksize); 212 if (ret == -1) { 213 goto out; 214 } 215 216 ret = nbd_init(fd, sock, nbdflags, size, blocksize); 217 if (ret == -1) { 218 goto out; 219 } 220 221 /* update partition table */ 222 pthread_create(&show_parts_thread, NULL, show_parts, NULL); 223 224 if (verbose) { 225 fprintf(stderr, "NBD device %s is now connected to %s\n", 226 device, srcpath); 227 } else { 228 /* Close stderr so that the qemu-nbd process exits. */ 229 dup2(STDOUT_FILENO, STDERR_FILENO); 230 } 231 232 ret = nbd_client(fd); 233 if (ret) { 234 goto out; 235 } 236 close(fd); 237 kill(getpid(), SIGTERM); 238 return (void *) EXIT_SUCCESS; 239 240 out: 241 kill(getpid(), SIGTERM); 242 return (void *) EXIT_FAILURE; 243 } 244 245 static int nbd_can_accept(void *opaque) 246 { 247 return nb_fds < shared; 248 } 249 250 static void nbd_client_closed(NBDClient *client) 251 { 252 nb_fds--; 253 qemu_notify_event(); 254 } 255 256 static void nbd_accept(void *opaque) 257 { 258 int server_fd = (uintptr_t) opaque; 259 struct sockaddr_in addr; 260 socklen_t addr_len = sizeof(addr); 261 262 int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len); 263 nbd_started = true; 264 if (fd != -1 && nbd_client_new(exp, fd, nbd_client_closed)) { 265 nb_fds++; 266 } 267 } 268 269 int main(int argc, char **argv) 270 { 271 BlockDriverState *bs; 272 off_t dev_offset = 0; 273 uint32_t nbdflags = 0; 274 bool disconnect = false; 275 const char *bindto = "0.0.0.0"; 276 int port = NBD_DEFAULT_PORT; 277 off_t fd_size; 278 const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t"; 279 struct option lopt[] = { 280 { "help", 0, NULL, 'h' }, 281 { "version", 0, NULL, 'V' }, 282 { "bind", 1, NULL, 'b' }, 283 { "port", 1, NULL, 'p' }, 284 { "socket", 1, NULL, 'k' }, 285 { "offset", 1, NULL, 'o' }, 286 { "read-only", 0, NULL, 'r' }, 287 { "partition", 1, NULL, 'P' }, 288 { "connect", 1, NULL, 'c' }, 289 { "disconnect", 0, NULL, 'd' }, 290 { "snapshot", 0, NULL, 's' }, 291 { "nocache", 0, NULL, 'n' }, 292 { "shared", 1, NULL, 'e' }, 293 { "persistent", 0, NULL, 't' }, 294 { "verbose", 0, NULL, 'v' }, 295 { NULL, 0, NULL, 0 } 296 }; 297 int ch; 298 int opt_ind = 0; 299 int li; 300 char *end; 301 int flags = BDRV_O_RDWR; 302 int partition = -1; 303 int ret; 304 int fd; 305 int persistent = 0; 306 pthread_t client_thread; 307 308 /* The client thread uses SIGTERM to interrupt the server. A signal 309 * handler ensures that "qemu-nbd -v -c" exits with a nice status code. 310 */ 311 struct sigaction sa_sigterm; 312 memset(&sa_sigterm, 0, sizeof(sa_sigterm)); 313 sa_sigterm.sa_handler = termsig_handler; 314 sigaction(SIGTERM, &sa_sigterm, NULL); 315 316 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { 317 switch (ch) { 318 case 's': 319 flags |= BDRV_O_SNAPSHOT; 320 break; 321 case 'n': 322 flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; 323 break; 324 case 'b': 325 bindto = optarg; 326 break; 327 case 'p': 328 li = strtol(optarg, &end, 0); 329 if (*end) { 330 errx(EXIT_FAILURE, "Invalid port `%s'", optarg); 331 } 332 if (li < 1 || li > 65535) { 333 errx(EXIT_FAILURE, "Port out of range `%s'", optarg); 334 } 335 port = (uint16_t)li; 336 break; 337 case 'o': 338 dev_offset = strtoll (optarg, &end, 0); 339 if (*end) { 340 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg); 341 } 342 if (dev_offset < 0) { 343 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg); 344 } 345 break; 346 case 'r': 347 nbdflags |= NBD_FLAG_READ_ONLY; 348 flags &= ~BDRV_O_RDWR; 349 break; 350 case 'P': 351 partition = strtol(optarg, &end, 0); 352 if (*end) 353 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg); 354 if (partition < 1 || partition > 8) 355 errx(EXIT_FAILURE, "Invalid partition %d", partition); 356 break; 357 case 'k': 358 sockpath = optarg; 359 if (sockpath[0] != '/') 360 errx(EXIT_FAILURE, "socket path must be absolute\n"); 361 break; 362 case 'd': 363 disconnect = true; 364 break; 365 case 'c': 366 device = optarg; 367 break; 368 case 'e': 369 shared = strtol(optarg, &end, 0); 370 if (*end) { 371 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg); 372 } 373 if (shared < 1) { 374 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n"); 375 } 376 break; 377 case 't': 378 persistent = 1; 379 break; 380 case 'v': 381 verbose = 1; 382 break; 383 case 'V': 384 version(argv[0]); 385 exit(0); 386 break; 387 case 'h': 388 usage(argv[0]); 389 exit(0); 390 break; 391 case '?': 392 errx(EXIT_FAILURE, "Try `%s --help' for more information.", 393 argv[0]); 394 } 395 } 396 397 if ((argc - optind) != 1) { 398 errx(EXIT_FAILURE, "Invalid number of argument.\n" 399 "Try `%s --help' for more information.", 400 argv[0]); 401 } 402 403 if (disconnect) { 404 fd = open(argv[optind], O_RDWR); 405 if (fd == -1) 406 err(EXIT_FAILURE, "Cannot open %s", argv[optind]); 407 408 nbd_disconnect(fd); 409 410 close(fd); 411 412 printf("%s disconnected\n", argv[optind]); 413 414 return 0; 415 } 416 417 if (device && !verbose) { 418 int stderr_fd[2]; 419 pid_t pid; 420 int ret; 421 422 if (qemu_pipe(stderr_fd) == -1) { 423 err(EXIT_FAILURE, "Error setting up communication pipe"); 424 } 425 426 /* Now daemonize, but keep a communication channel open to 427 * print errors and exit with the proper status code. 428 */ 429 pid = fork(); 430 if (pid == 0) { 431 close(stderr_fd[0]); 432 ret = qemu_daemon(0, 0); 433 434 /* Temporarily redirect stderr to the parent's pipe... */ 435 dup2(stderr_fd[1], STDERR_FILENO); 436 if (ret == -1) { 437 err(EXIT_FAILURE, "Failed to daemonize"); 438 } 439 440 /* ... close the descriptor we inherited and go on. */ 441 close(stderr_fd[1]); 442 } else { 443 bool errors = false; 444 char *buf; 445 446 /* In the parent. Print error messages from the child until 447 * it closes the pipe. 448 */ 449 close(stderr_fd[1]); 450 buf = g_malloc(1024); 451 while ((ret = read(stderr_fd[0], buf, 1024)) > 0) { 452 errors = true; 453 ret = qemu_write_full(STDERR_FILENO, buf, ret); 454 if (ret == -1) { 455 exit(EXIT_FAILURE); 456 } 457 } 458 if (ret == -1) { 459 err(EXIT_FAILURE, "Cannot read from daemon"); 460 } 461 462 /* Usually the daemon should not print any message. 463 * Exit with zero status in that case. 464 */ 465 exit(errors); 466 } 467 } 468 469 if (device) { 470 /* Open before spawning new threads. In the future, we may 471 * drop privileges after opening. 472 */ 473 fd = open(device, O_RDWR); 474 if (fd == -1) { 475 err(EXIT_FAILURE, "Failed to open %s", device); 476 } 477 478 if (sockpath == NULL) { 479 sockpath = g_malloc(128); 480 snprintf(sockpath, 128, SOCKET_PATH, basename(device)); 481 } 482 } 483 484 bdrv_init(); 485 atexit(bdrv_close_all); 486 487 bs = bdrv_new("hda"); 488 srcpath = argv[optind]; 489 if ((ret = bdrv_open(bs, srcpath, flags, NULL)) < 0) { 490 errno = -ret; 491 err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]); 492 } 493 494 fd_size = bs->total_sectors * 512; 495 496 if (partition != -1 && 497 find_partition(bs, partition, &dev_offset, &fd_size)) { 498 err(EXIT_FAILURE, "Could not find partition %d", partition); 499 } 500 501 exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags); 502 503 if (sockpath) { 504 fd = unix_socket_incoming(sockpath); 505 } else { 506 fd = tcp_socket_incoming(bindto, port); 507 } 508 509 if (fd == -1) { 510 return 1; 511 } 512 513 if (device) { 514 int ret; 515 516 ret = pthread_create(&client_thread, NULL, nbd_client_thread, &fd); 517 if (ret != 0) { 518 errx(EXIT_FAILURE, "Failed to create client thread: %s", 519 strerror(ret)); 520 } 521 } else { 522 /* Shut up GCC warnings. */ 523 memset(&client_thread, 0, sizeof(client_thread)); 524 } 525 526 qemu_init_main_loop(); 527 qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL, 528 (void *)(uintptr_t)fd); 529 530 do { 531 main_loop_wait(false); 532 } while (!sigterm_reported && (persistent || !nbd_started || nb_fds > 0)); 533 534 nbd_export_close(exp); 535 if (sockpath) { 536 unlink(sockpath); 537 } 538 539 if (device) { 540 void *ret; 541 pthread_join(client_thread, &ret); 542 exit(ret != NULL); 543 } else { 544 exit(EXIT_SUCCESS); 545 } 546 } 547