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 *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 errno = -EINVAL; 130 return -1; 131 } 132 133 for (i = 0; i < 4; i++) { 134 read_partition(&data[446 + 16 * i], &mbr[i]); 135 136 if (!mbr[i].nb_sectors_abs) 137 continue; 138 139 if (mbr[i].system == 0xF || mbr[i].system == 0x5) { 140 struct partition_record ext[4]; 141 uint8_t data1[512]; 142 int j; 143 144 if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) { 145 errno = -ret; 146 err(EXIT_FAILURE, "error while reading"); 147 } 148 149 for (j = 0; j < 4; j++) { 150 read_partition(&data1[446 + 16 * j], &ext[j]); 151 if (!ext[j].nb_sectors_abs) 152 continue; 153 154 if ((ext_partnum + j + 1) == partition) { 155 *offset = (uint64_t)ext[j].start_sector_abs << 9; 156 *size = (uint64_t)ext[j].nb_sectors_abs << 9; 157 return 0; 158 } 159 } 160 ext_partnum += 4; 161 } else if ((i + 1) == partition) { 162 *offset = (uint64_t)mbr[i].start_sector_abs << 9; 163 *size = (uint64_t)mbr[i].nb_sectors_abs << 9; 164 return 0; 165 } 166 } 167 168 errno = -ENOENT; 169 return -1; 170 } 171 172 static void termsig_handler(int signum) 173 { 174 sigterm_reported = true; 175 qemu_notify_event(); 176 } 177 178 static void *show_parts(void *arg) 179 { 180 char *device = arg; 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 char *device = arg; 198 off_t size; 199 size_t blocksize; 200 uint32_t nbdflags; 201 int fd, 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 fd = open(device, O_RDWR); 217 if (fd == -1) { 218 /* Linux-only, we can use %m in printf. */ 219 fprintf(stderr, "Failed to open %s: %m", device); 220 goto out; 221 } 222 223 ret = nbd_init(fd, sock, nbdflags, size, blocksize); 224 if (ret == -1) { 225 goto out; 226 } 227 228 /* update partition table */ 229 pthread_create(&show_parts_thread, NULL, show_parts, device); 230 231 if (verbose) { 232 fprintf(stderr, "NBD device %s is now connected to %s\n", 233 device, srcpath); 234 } else { 235 /* Close stderr so that the qemu-nbd process exits. */ 236 dup2(STDOUT_FILENO, STDERR_FILENO); 237 } 238 239 ret = nbd_client(fd); 240 if (ret) { 241 goto out; 242 } 243 close(fd); 244 kill(getpid(), SIGTERM); 245 return (void *) EXIT_SUCCESS; 246 247 out: 248 kill(getpid(), SIGTERM); 249 return (void *) EXIT_FAILURE; 250 } 251 252 static int nbd_can_accept(void *opaque) 253 { 254 return nb_fds < shared; 255 } 256 257 static void nbd_client_closed(NBDClient *client) 258 { 259 nb_fds--; 260 qemu_notify_event(); 261 } 262 263 static void nbd_accept(void *opaque) 264 { 265 int server_fd = (uintptr_t) opaque; 266 struct sockaddr_in addr; 267 socklen_t addr_len = sizeof(addr); 268 269 int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len); 270 nbd_started = true; 271 if (fd != -1 && nbd_client_new(exp, fd, nbd_client_closed)) { 272 nb_fds++; 273 } 274 } 275 276 int main(int argc, char **argv) 277 { 278 BlockDriverState *bs; 279 off_t dev_offset = 0; 280 uint32_t nbdflags = 0; 281 bool disconnect = false; 282 const char *bindto = "0.0.0.0"; 283 char *device = NULL; 284 int port = NBD_DEFAULT_PORT; 285 off_t fd_size; 286 const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t"; 287 struct option lopt[] = { 288 { "help", 0, NULL, 'h' }, 289 { "version", 0, NULL, 'V' }, 290 { "bind", 1, NULL, 'b' }, 291 { "port", 1, NULL, 'p' }, 292 { "socket", 1, NULL, 'k' }, 293 { "offset", 1, NULL, 'o' }, 294 { "read-only", 0, NULL, 'r' }, 295 { "partition", 1, NULL, 'P' }, 296 { "connect", 1, NULL, 'c' }, 297 { "disconnect", 0, NULL, 'd' }, 298 { "snapshot", 0, NULL, 's' }, 299 { "nocache", 0, NULL, 'n' }, 300 { "shared", 1, NULL, 'e' }, 301 { "persistent", 0, NULL, 't' }, 302 { "verbose", 0, NULL, 'v' }, 303 { NULL, 0, NULL, 0 } 304 }; 305 int ch; 306 int opt_ind = 0; 307 int li; 308 char *end; 309 int flags = BDRV_O_RDWR; 310 int partition = -1; 311 int ret; 312 int fd; 313 int persistent = 0; 314 pthread_t client_thread; 315 316 /* The client thread uses SIGTERM to interrupt the server. A signal 317 * handler ensures that "qemu-nbd -v -c" exits with a nice status code. 318 */ 319 struct sigaction sa_sigterm; 320 memset(&sa_sigterm, 0, sizeof(sa_sigterm)); 321 sa_sigterm.sa_handler = termsig_handler; 322 sigaction(SIGTERM, &sa_sigterm, NULL); 323 324 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { 325 switch (ch) { 326 case 's': 327 flags |= BDRV_O_SNAPSHOT; 328 break; 329 case 'n': 330 flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; 331 break; 332 case 'b': 333 bindto = optarg; 334 break; 335 case 'p': 336 li = strtol(optarg, &end, 0); 337 if (*end) { 338 errx(EXIT_FAILURE, "Invalid port `%s'", optarg); 339 } 340 if (li < 1 || li > 65535) { 341 errx(EXIT_FAILURE, "Port out of range `%s'", optarg); 342 } 343 port = (uint16_t)li; 344 break; 345 case 'o': 346 dev_offset = strtoll (optarg, &end, 0); 347 if (*end) { 348 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg); 349 } 350 if (dev_offset < 0) { 351 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg); 352 } 353 break; 354 case 'r': 355 nbdflags |= NBD_FLAG_READ_ONLY; 356 flags &= ~BDRV_O_RDWR; 357 break; 358 case 'P': 359 partition = strtol(optarg, &end, 0); 360 if (*end) 361 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg); 362 if (partition < 1 || partition > 8) 363 errx(EXIT_FAILURE, "Invalid partition %d", partition); 364 break; 365 case 'k': 366 sockpath = optarg; 367 if (sockpath[0] != '/') 368 errx(EXIT_FAILURE, "socket path must be absolute\n"); 369 break; 370 case 'd': 371 disconnect = true; 372 break; 373 case 'c': 374 device = optarg; 375 break; 376 case 'e': 377 shared = strtol(optarg, &end, 0); 378 if (*end) { 379 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg); 380 } 381 if (shared < 1) { 382 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n"); 383 } 384 break; 385 case 't': 386 persistent = 1; 387 break; 388 case 'v': 389 verbose = 1; 390 break; 391 case 'V': 392 version(argv[0]); 393 exit(0); 394 break; 395 case 'h': 396 usage(argv[0]); 397 exit(0); 398 break; 399 case '?': 400 errx(EXIT_FAILURE, "Try `%s --help' for more information.", 401 argv[0]); 402 } 403 } 404 405 if ((argc - optind) != 1) { 406 errx(EXIT_FAILURE, "Invalid number of argument.\n" 407 "Try `%s --help' for more information.", 408 argv[0]); 409 } 410 411 if (disconnect) { 412 fd = open(argv[optind], O_RDWR); 413 if (fd == -1) 414 err(EXIT_FAILURE, "Cannot open %s", argv[optind]); 415 416 nbd_disconnect(fd); 417 418 close(fd); 419 420 printf("%s disconnected\n", argv[optind]); 421 422 return 0; 423 } 424 425 if (device && !verbose) { 426 int stderr_fd[2]; 427 pid_t pid; 428 int ret; 429 430 if (qemu_pipe(stderr_fd) == -1) { 431 err(EXIT_FAILURE, "Error setting up communication pipe"); 432 } 433 434 /* Now daemonize, but keep a communication channel open to 435 * print errors and exit with the proper status code. 436 */ 437 pid = fork(); 438 if (pid == 0) { 439 close(stderr_fd[0]); 440 ret = qemu_daemon(1, 0); 441 442 /* Temporarily redirect stderr to the parent's pipe... */ 443 dup2(stderr_fd[1], STDERR_FILENO); 444 if (ret == -1) { 445 err(EXIT_FAILURE, "Failed to daemonize"); 446 } 447 448 /* ... close the descriptor we inherited and go on. */ 449 close(stderr_fd[1]); 450 } else { 451 bool errors = false; 452 char *buf; 453 454 /* In the parent. Print error messages from the child until 455 * it closes the pipe. 456 */ 457 close(stderr_fd[1]); 458 buf = g_malloc(1024); 459 while ((ret = read(stderr_fd[0], buf, 1024)) > 0) { 460 errors = true; 461 ret = qemu_write_full(STDERR_FILENO, buf, ret); 462 if (ret == -1) { 463 exit(EXIT_FAILURE); 464 } 465 } 466 if (ret == -1) { 467 err(EXIT_FAILURE, "Cannot read from daemon"); 468 } 469 470 /* Usually the daemon should not print any message. 471 * Exit with zero status in that case. 472 */ 473 exit(errors); 474 } 475 } 476 477 if (device != NULL && sockpath == NULL) { 478 sockpath = g_malloc(128); 479 snprintf(sockpath, 128, SOCKET_PATH, basename(device)); 480 } 481 482 bdrv_init(); 483 atexit(bdrv_close_all); 484 485 bs = bdrv_new("hda"); 486 srcpath = argv[optind]; 487 if ((ret = bdrv_open(bs, srcpath, flags, NULL)) < 0) { 488 errno = -ret; 489 err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]); 490 } 491 492 fd_size = bs->total_sectors * 512; 493 494 if (partition != -1 && 495 find_partition(bs, partition, &dev_offset, &fd_size)) { 496 err(EXIT_FAILURE, "Could not find partition %d", partition); 497 } 498 499 exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags); 500 501 if (sockpath) { 502 fd = unix_socket_incoming(sockpath); 503 } else { 504 fd = tcp_socket_incoming(bindto, port); 505 } 506 507 if (fd == -1) { 508 return 1; 509 } 510 511 if (device) { 512 int ret; 513 514 ret = pthread_create(&client_thread, NULL, nbd_client_thread, device); 515 if (ret != 0) { 516 errx(EXIT_FAILURE, "Failed to create client thread: %s", 517 strerror(ret)); 518 } 519 } else { 520 /* Shut up GCC warnings. */ 521 memset(&client_thread, 0, sizeof(client_thread)); 522 } 523 524 qemu_init_main_loop(); 525 qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL, 526 (void *)(uintptr_t)fd); 527 528 /* now when the initialization is (almost) complete, chdir("/") 529 * to free any busy filesystems */ 530 if (chdir("/") < 0) { 531 err(EXIT_FAILURE, "Could not chdir to root directory"); 532 } 533 534 do { 535 main_loop_wait(false); 536 } while (!sigterm_reported && (persistent || !nbd_started || nb_fds > 0)); 537 538 nbd_export_close(exp); 539 if (sockpath) { 540 unlink(sockpath); 541 } 542 543 if (device) { 544 void *ret; 545 pthread_join(client_thread, &ret); 546 exit(ret != NULL); 547 } else { 548 exit(EXIT_SUCCESS); 549 } 550 } 551