qemu-nbd.c

   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 "sysemu/block-backend.h"
  21 #include "block/block_int.h"
  22 #include "block/nbd.h"
  23 #include "qemu/main-loop.h"
  24 #include "qemu/sockets.h"
  25 #include "qemu/error-report.h"
  26 #include "block/snapshot.h"
  27 #include "qapi/util.h"
  28
  29 #include <stdarg.h>
  30 #include <stdio.h>
  31 #include <getopt.h>
  32 #include <err.h>
  33 #include <sys/types.h>
  34 #include <sys/socket.h>
  35 #include <netinet/in.h>
  36 #include <netinet/tcp.h>
  37 #include <arpa/inet.h>
  38 #include <signal.h>
  39 #include <libgen.h>
  40 #include <pthread.h>
  41
  42 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  43 #define QEMU_NBD_OPT_CACHE         1
  44 #define QEMU_NBD_OPT_AIO           2
  45 #define QEMU_NBD_OPT_DISCARD       3
  46 #define QEMU_NBD_OPT_DETECT_ZEROES 4
  47
  48 static NBDExport *exp;
  49 static int verbose;
  50 static char *srcpath;
  51 static char *sockpath;
  52 static int persistent = 0;
  53 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  54 static int shared = 1;
  55 static int nb_fds;
  56
  57 static void usage(const char *name)
  58 {
  59     (printf) (
  60 "Usage: %s [OPTIONS] FILE\n"
  61 "QEMU Disk Network Block Device Server\n"
  62 "\n"
  63 "  -h, --help                display this help and exit\n"
  64 "  -V, --version             output version information and exit\n"
  65 "\n"
  66 "Connection properties:\n"
  67 "  -p, --port=PORT           port to listen on (default `%d')\n"
  68 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  69 "  -k, --socket=PATH         path to the unix socket\n"
  70 "                            (default '"SOCKET_PATH"')\n"
  71 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  72 "  -t, --persistent          don't exit on the last connection\n"
  73 "  -v, --verbose             display extra debugging information\n"
  74 "\n"
  75 "Exposing part of the image:\n"
  76 "  -o, --offset=OFFSET       offset into the image\n"
  77 "  -P, --partition=NUM       only expose partition NUM\n"
  78 "\n"
  79 #ifdef __linux__
  80 "Kernel NBD client support:\n"
  81 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
  82 "  -d, --disconnect          disconnect the specified device\n"
  83 "\n"
  84 #endif
  85 "\n"
  86 "Block device options:\n"
  87 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
  88 "  -r, --read-only           export read-only\n"
  89 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
  90 "                            file with backing_file=FILE, redirect the write to\n"
  91 "                            the temporary one\n"
  92 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
  93 "                            load an internal snapshot inside FILE and export it\n"
  94 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
  95 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
  96 "                            '[ID_OR_NAME]'\n"
  97 "  -n, --nocache             disable host cache\n"
  98 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
  99 #ifdef CONFIG_LINUX_AIO
 100 "      --aio=MODE            set AIO mode (native or threads)\n"
 101 #endif
 102 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 103 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, discard)\n"
 104 "\n"
 105 "Report bugs to <qemu-devel@nongnu.org>\n"
 106     , name, NBD_DEFAULT_PORT, "DEVICE");
 107 }
 108
 109 static void version(const char *name)
 110 {
 111     printf(
 112 "%s version 0.0.1\n"
 113 "Written by Anthony Liguori.\n"
 114 "\n"
 115 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
 116 "This is free software; see the source for copying conditions.  There is NO\n"
 117 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 118     , name);
 119 }
 120
 121 struct partition_record
 122 {
 123     uint8_t bootable;
 124     uint8_t start_head;
 125     uint32_t start_cylinder;
 126     uint8_t start_sector;
 127     uint8_t system;
 128     uint8_t end_head;
 129     uint8_t end_cylinder;
 130     uint8_t end_sector;
 131     uint32_t start_sector_abs;
 132     uint32_t nb_sectors_abs;
 133 };
 134
 135 static void read_partition(uint8_t *p, struct partition_record *r)
 136 {
 137     r->bootable = p[0];
 138     r->start_head = p[1];
 139     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 140     r->start_sector = p[2] & 0x3f;
 141     r->system = p[4];
 142     r->end_head = p[5];
 143     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 144     r->end_sector = p[6] & 0x3f;
 145     r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24;
 146     r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24;
 147 }
 148
 149 static int find_partition(BlockBackend *blk, int partition,
 150                           off_t *offset, off_t *size)
 151 {
 152     struct partition_record mbr[4];
 153     uint8_t data[512];
 154     int i;
 155     int ext_partnum = 4;
 156     int ret;
 157
 158     if ((ret = blk_read(blk, 0, data, 1)) < 0) {
 159         errno = -ret;
 160         err(EXIT_FAILURE, "error while reading");
 161     }
 162
 163     if (data[510] != 0x55 || data[511] != 0xaa) {
 164         return -EINVAL;
 165     }
 166
 167     for (i = 0; i < 4; i++) {
 168         read_partition(&data[446 + 16 * i], &mbr[i]);
 169
 170         if (!mbr[i].nb_sectors_abs)
 171             continue;
 172
 173         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 174             struct partition_record ext[4];
 175             uint8_t data1[512];
 176             int j;
 177
 178             if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 0) {
 179                 errno = -ret;
 180                 err(EXIT_FAILURE, "error while reading");
 181             }
 182
 183             for (j = 0; j < 4; j++) {
 184                 read_partition(&data1[446 + 16 * j], &ext[j]);
 185                 if (!ext[j].nb_sectors_abs)
 186                     continue;
 187
 188                 if ((ext_partnum + j + 1) == partition) {
 189                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 190                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 191                     return 0;
 192                 }
 193             }
 194             ext_partnum += 4;
 195         } else if ((i + 1) == partition) {
 196             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 197             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 198             return 0;
 199         }
 200     }
 201
 202     return -ENOENT;
 203 }
 204
 205 static void termsig_handler(int signum)
 206 {
 207     state = TERMINATE;
 208     qemu_notify_event();
 209 }
 210
 211 static void combine_addr(char *buf, size_t len, const char* address,
 212                          uint16_t port)
 213 {
 214     /* If the address-part contains a colon, it's an IPv6 IP so needs [] */
 215     if (strstr(address, ":")) {
 216         snprintf(buf, len, "[%s]:%u", address, port);
 217     } else {
 218         snprintf(buf, len, "%s:%u", address, port);
 219     }
 220 }
 221
 222 static int tcp_socket_incoming(const char *address, uint16_t port)
 223 {
 224     char address_and_port[128];
 225     Error *local_err = NULL;
 226
 227     combine_addr(address_and_port, 128, address, port);
 228     int fd = inet_listen(address_and_port, NULL, 0, SOCK_STREAM, 0, &local_err);
 229
 230     if (local_err != NULL) {
 231         error_report_err(local_err);
 232     }
 233     return fd;
 234 }
 235
 236 static int unix_socket_incoming(const char *path)
 237 {
 238     Error *local_err = NULL;
 239     int fd = unix_listen(path, NULL, 0, &local_err);
 240
 241     if (local_err != NULL) {
 242         error_report_err(local_err);
 243     }
 244     return fd;
 245 }
 246
 247 static int unix_socket_outgoing(const char *path)
 248 {
 249     Error *local_err = NULL;
 250     int fd = unix_connect(path, &local_err);
 251
 252     if (local_err != NULL) {
 253         error_report_err(local_err);
 254     }
 255     return fd;
 256 }
 257
 258 static void *show_parts(void *arg)
 259 {
 260     char *device = arg;
 261     int nbd;
 262
 263     /* linux just needs an open() to trigger
 264      * the partition table update
 265      * but remember to load the module with max_part != 0 :
 266      *     modprobe nbd max_part=63
 267      */
 268     nbd = open(device, O_RDWR);
 269     if (nbd >= 0) {
 270         close(nbd);
 271     }
 272     return NULL;
 273 }
 274
 275 static void *nbd_client_thread(void *arg)
 276 {
 277     char *device = arg;
 278     off_t size;
 279     size_t blocksize;
 280     uint32_t nbdflags;
 281     int fd, sock;
 282     int ret;
 283     pthread_t show_parts_thread;
 284     Error *local_error = NULL;
 285
 286     sock = unix_socket_outgoing(sockpath);
 287     if (sock < 0) {
 288         goto out;
 289     }
 290
 291     ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
 292                                 &size, &blocksize, &local_error);
 293     if (ret < 0) {
 294         if (local_error) {
 295             fprintf(stderr, "%s\n", error_get_pretty(local_error));
 296             error_free(local_error);
 297         }
 298         goto out_socket;
 299     }
 300
 301     fd = open(device, O_RDWR);
 302     if (fd < 0) {
 303         /* Linux-only, we can use %m in printf.  */
 304         fprintf(stderr, "Failed to open %s: %m\n", device);
 305         goto out_socket;
 306     }
 307
 308     ret = nbd_init(fd, sock, nbdflags, size, blocksize);
 309     if (ret < 0) {
 310         goto out_fd;
 311     }
 312
 313     /* update partition table */
 314     pthread_create(&show_parts_thread, NULL, show_parts, device);
 315
 316     if (verbose) {
 317         fprintf(stderr, "NBD device %s is now connected to %s\n",
 318                 device, srcpath);
 319     } else {
 320         /* Close stderr so that the qemu-nbd process exits.  */
 321         dup2(STDOUT_FILENO, STDERR_FILENO);
 322     }
 323
 324     ret = nbd_client(fd);
 325     if (ret) {
 326         goto out_fd;
 327     }
 328     close(fd);
 329     kill(getpid(), SIGTERM);
 330     return (void *) EXIT_SUCCESS;
 331
 332 out_fd:
 333     close(fd);
 334 out_socket:
 335     closesocket(sock);
 336 out:
 337     kill(getpid(), SIGTERM);
 338     return (void *) EXIT_FAILURE;
 339 }
 340
 341 static int nbd_can_accept(void *opaque)
 342 {
 343     return nb_fds < shared;
 344 }
 345
 346 static void nbd_export_closed(NBDExport *exp)
 347 {
 348     assert(state == TERMINATING);
 349     state = TERMINATED;
 350 }
 351
 352 static void nbd_client_closed(NBDClient *client)
 353 {
 354     nb_fds--;
 355     if (nb_fds == 0 && !persistent && state == RUNNING) {
 356         state = TERMINATE;
 357     }
 358     qemu_notify_event();
 359     nbd_client_put(client);
 360 }
 361
 362 static void nbd_accept(void *opaque)
 363 {
 364     int server_fd = (uintptr_t) opaque;
 365     struct sockaddr_in addr;
 366     socklen_t addr_len = sizeof(addr);
 367
 368     int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
 369     if (fd < 0) {
 370         perror("accept");
 371         return;
 372     }
 373
 374     if (state >= TERMINATE) {
 375         close(fd);
 376         return;
 377     }
 378
 379     if (nbd_client_new(exp, fd, nbd_client_closed)) {
 380         nb_fds++;
 381     } else {
 382         shutdown(fd, 2);
 383         close(fd);
 384     }
 385 }
 386
 387 int main(int argc, char **argv)
 388 {
 389     BlockBackend *blk;
 390     BlockDriverState *bs;
 391     off_t dev_offset = 0;
 392     uint32_t nbdflags = 0;
 393     bool disconnect = false;
 394     const char *bindto = "0.0.0.0";
 395     char *device = NULL;
 396     int port = NBD_DEFAULT_PORT;
 397     off_t fd_size;
 398     QemuOpts *sn_opts = NULL;
 399     const char *sn_id_or_name = NULL;
 400     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
 401     struct option lopt[] = {
 402         { "help", 0, NULL, 'h' },
 403         { "version", 0, NULL, 'V' },
 404         { "bind", 1, NULL, 'b' },
 405         { "port", 1, NULL, 'p' },
 406         { "socket", 1, NULL, 'k' },
 407         { "offset", 1, NULL, 'o' },
 408         { "read-only", 0, NULL, 'r' },
 409         { "partition", 1, NULL, 'P' },
 410         { "connect", 1, NULL, 'c' },
 411         { "disconnect", 0, NULL, 'd' },
 412         { "snapshot", 0, NULL, 's' },
 413         { "load-snapshot", 1, NULL, 'l' },
 414         { "nocache", 0, NULL, 'n' },
 415         { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
 416 #ifdef CONFIG_LINUX_AIO
 417         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 418 #endif
 419         { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
 420         { "detect-zeroes", 1, NULL, QEMU_NBD_OPT_DETECT_ZEROES },
 421         { "shared", 1, NULL, 'e' },
 422         { "format", 1, NULL, 'f' },
 423         { "persistent", 0, NULL, 't' },
 424         { "verbose", 0, NULL, 'v' },
 425         { NULL, 0, NULL, 0 }
 426     };
 427     int ch;
 428     int opt_ind = 0;
 429     int li;
 430     char *end;
 431     int flags = BDRV_O_RDWR;
 432     int partition = -1;
 433     int ret = 0;
 434     int fd;
 435     bool seen_cache = false;
 436     bool seen_discard = false;
 437 #ifdef CONFIG_LINUX_AIO
 438     bool seen_aio = false;
 439 #endif
 440     pthread_t client_thread;
 441     const char *fmt = NULL;
 442     Error *local_err = NULL;
 443     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 444     QDict *options = NULL;
 445
 446     /* The client thread uses SIGTERM to interrupt the server.  A signal
 447      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 448      */
 449     struct sigaction sa_sigterm;
 450     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 451     sa_sigterm.sa_handler = termsig_handler;
 452     sigaction(SIGTERM, &sa_sigterm, NULL);
 453     qemu_init_exec_dir(argv[0]);
 454
 455     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 456         switch (ch) {
 457         case 's':
 458             flags |= BDRV_O_SNAPSHOT;
 459             break;
 460         case 'n':
 461             optarg = (char *) "none";
 462             /* fallthrough */
 463         case QEMU_NBD_OPT_CACHE:
 464             if (seen_cache) {
 465                 errx(EXIT_FAILURE, "-n and --cache can only be specified once");
 466             }
 467             seen_cache = true;
 468             if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
 469                 errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
 470             }
 471             break;
 472 #ifdef CONFIG_LINUX_AIO
 473         case QEMU_NBD_OPT_AIO:
 474             if (seen_aio) {
 475                 errx(EXIT_FAILURE, "--aio can only be specified once");
 476             }
 477             seen_aio = true;
 478             if (!strcmp(optarg, "native")) {
 479                 flags |= BDRV_O_NATIVE_AIO;
 480             } else if (!strcmp(optarg, "threads")) {
 481                 /* this is the default */
 482             } else {
 483                errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
 484             }
 485             break;
 486 #endif
 487         case QEMU_NBD_OPT_DISCARD:
 488             if (seen_discard) {
 489                 errx(EXIT_FAILURE, "--discard can only be specified once");
 490             }
 491             seen_discard = true;
 492             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 493                 errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
 494             }
 495             break;
 496         case QEMU_NBD_OPT_DETECT_ZEROES:
 497             detect_zeroes =
 498                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
 499                                 optarg,
 500                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_MAX,
 501                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 502                                 &local_err);
 503             if (local_err) {
 504                 errx(EXIT_FAILURE, "Failed to parse detect_zeroes mode: %s",
 505                      error_get_pretty(local_err));
 506             }
 507             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 508                 !(flags & BDRV_O_UNMAP)) {
 509                 errx(EXIT_FAILURE, "setting detect-zeroes to unmap is not allowed "
 510                                    "without setting discard operation to unmap");
 511             }
 512             break;
 513         case 'b':
 514             bindto = optarg;
 515             break;
 516         case 'p':
 517             li = strtol(optarg, &end, 0);
 518             if (*end) {
 519                 errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
 520             }
 521             if (li < 1 || li > 65535) {
 522                 errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
 523             }
 524             port = (uint16_t)li;
 525             break;
 526         case 'o':
 527                 dev_offset = strtoll (optarg, &end, 0);
 528             if (*end) {
 529                 errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
 530             }
 531             if (dev_offset < 0) {
 532                 errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
 533             }
 534             break;
 535         case 'l':
 536             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 537                 sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0);
 538                 if (!sn_opts) {
 539                     errx(EXIT_FAILURE, "Failed in parsing snapshot param `%s'",
 540                          optarg);
 541                 }
 542             } else {
 543                 sn_id_or_name = optarg;
 544             }
 545             /* fall through */
 546         case 'r':
 547             nbdflags |= NBD_FLAG_READ_ONLY;
 548             flags &= ~BDRV_O_RDWR;
 549             break;
 550         case 'P':
 551             partition = strtol(optarg, &end, 0);
 552             if (*end) {
 553                 errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
 554             }
 555             if (partition < 1 || partition > 8) {
 556                 errx(EXIT_FAILURE, "Invalid partition %d", partition);
 557             }
 558             break;
 559         case 'k':
 560             sockpath = optarg;
 561             if (sockpath[0] != '/') {
 562                 errx(EXIT_FAILURE, "socket path must be absolute\n");
 563             }
 564             break;
 565         case 'd':
 566             disconnect = true;
 567             break;
 568         case 'c':
 569             device = optarg;
 570             break;
 571         case 'e':
 572             shared = strtol(optarg, &end, 0);
 573             if (*end) {
 574                 errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
 575             }
 576             if (shared < 1) {
 577                 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
 578             }
 579             break;
 580         case 'f':
 581             fmt = optarg;
 582             break;
 583         case 't':
 584             persistent = 1;
 585             break;
 586         case 'v':
 587             verbose = 1;
 588             break;
 589         case 'V':
 590             version(argv[0]);
 591             exit(0);
 592             break;
 593         case 'h':
 594             usage(argv[0]);
 595             exit(0);
 596             break;
 597         case '?':
 598             errx(EXIT_FAILURE, "Try `%s --help' for more information.",
 599                  argv[0]);
 600         }
 601     }
 602
 603     if ((argc - optind) != 1) {
 604         errx(EXIT_FAILURE, "Invalid number of argument.\n"
 605              "Try `%s --help' for more information.",
 606              argv[0]);
 607     }
 608
 609     if (disconnect) {
 610         fd = open(argv[optind], O_RDWR);
 611         if (fd < 0) {
 612             err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
 613         }
 614         nbd_disconnect(fd);
 615
 616         close(fd);
 617
 618         printf("%s disconnected\n", argv[optind]);
 619
 620         return 0;
 621     }
 622
 623     if (device && !verbose) {
 624         int stderr_fd[2];
 625         pid_t pid;
 626         int ret;
 627
 628         if (qemu_pipe(stderr_fd) < 0) {
 629             err(EXIT_FAILURE, "Error setting up communication pipe");
 630         }
 631
 632         /* Now daemonize, but keep a communication channel open to
 633          * print errors and exit with the proper status code.
 634          */
 635         pid = fork();
 636         if (pid == 0) {
 637             close(stderr_fd[0]);
 638             ret = qemu_daemon(1, 0);
 639
 640             /* Temporarily redirect stderr to the parent's pipe...  */
 641             dup2(stderr_fd[1], STDERR_FILENO);
 642             if (ret < 0) {
 643                 err(EXIT_FAILURE, "Failed to daemonize");
 644             }
 645
 646             /* ... close the descriptor we inherited and go on.  */
 647             close(stderr_fd[1]);
 648         } else {
 649             bool errors = false;
 650             char *buf;
 651
 652             /* In the parent.  Print error messages from the child until
 653              * it closes the pipe.
 654              */
 655             close(stderr_fd[1]);
 656             buf = g_malloc(1024);
 657             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 658                 errors = true;
 659                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 660                 if (ret < 0) {
 661                     exit(EXIT_FAILURE);
 662                 }
 663             }
 664             if (ret < 0) {
 665                 err(EXIT_FAILURE, "Cannot read from daemon");
 666             }
 667
 668             /* Usually the daemon should not print any message.
 669              * Exit with zero status in that case.
 670              */
 671             exit(errors);
 672         }
 673     }
 674
 675     if (device != NULL && sockpath == NULL) {
 676         sockpath = g_malloc(128);
 677         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 678     }
 679
 680     if (qemu_init_main_loop(&local_err)) {
 681         error_report_err(local_err);
 682         exit(EXIT_FAILURE);
 683     }
 684     bdrv_init();
 685     atexit(bdrv_close_all);
 686
 687     if (fmt) {
 688         options = qdict_new();
 689         qdict_put(options, "driver", qstring_from_str(fmt));
 690     }
 691
 692     srcpath = argv[optind];
 693     blk = blk_new_open("hda", srcpath, NULL, options, flags, &local_err);
 694     if (!blk) {
 695         errx(EXIT_FAILURE, "Failed to blk_new_open '%s': %s", argv[optind],
 696              error_get_pretty(local_err));
 697     }
 698     bs = blk_bs(blk);
 699
 700     if (sn_opts) {
 701         ret = bdrv_snapshot_load_tmp(bs,
 702                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 703                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 704                                      &local_err);
 705     } else if (sn_id_or_name) {
 706         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 707                                                    &local_err);
 708     }
 709     if (ret < 0) {
 710         errno = -ret;
 711         err(EXIT_FAILURE,
 712             "Failed to load snapshot: %s",
 713             error_get_pretty(local_err));
 714     }
 715
 716     bs->detect_zeroes = detect_zeroes;
 717     fd_size = blk_getlength(blk);
 718
 719     if (partition != -1) {
 720         ret = find_partition(blk, partition, &dev_offset, &fd_size);
 721         if (ret < 0) {
 722             errno = -ret;
 723             err(EXIT_FAILURE, "Could not find partition %d", partition);
 724         }
 725     }
 726
 727     exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed);
 728
 729     if (sockpath) {
 730         fd = unix_socket_incoming(sockpath);
 731     } else {
 732         fd = tcp_socket_incoming(bindto, port);
 733     }
 734
 735     if (fd < 0) {
 736         return 1;
 737     }
 738
 739     if (device) {
 740         int ret;
 741
 742         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 743         if (ret != 0) {
 744             errx(EXIT_FAILURE, "Failed to create client thread: %s",
 745                  strerror(ret));
 746         }
 747     } else {
 748         /* Shut up GCC warnings.  */
 749         memset(&client_thread, 0, sizeof(client_thread));
 750     }
 751
 752     qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
 753                          (void *)(uintptr_t)fd);
 754
 755     /* now when the initialization is (almost) complete, chdir("/")
 756      * to free any busy filesystems */
 757     if (chdir("/") < 0) {
 758         err(EXIT_FAILURE, "Could not chdir to root directory");
 759     }
 760
 761     state = RUNNING;
 762     do {
 763         main_loop_wait(false);
 764         if (state == TERMINATE) {
 765             state = TERMINATING;
 766             nbd_export_close(exp);
 767             nbd_export_put(exp);
 768             exp = NULL;
 769         }
 770     } while (state != TERMINATED);
 771
 772     blk_unref(blk);
 773     if (sockpath) {
 774         unlink(sockpath);
 775     }
 776
 777     qemu_opts_del(sn_opts);
 778
 779     if (device) {
 780         void *ret;
 781         pthread_join(client_thread, &ret);
 782         exit(ret != NULL);
 783     } else {
 784         exit(EXIT_SUCCESS);
 785     }
 786 }