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 #include "qapi/qmp/qstring.h"
  29
  30 #include <stdarg.h>
  31 #include <stdio.h>
  32 #include <getopt.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 SocketAddress *saddr;
  52 static int persistent = 0;
  53 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  54 static int shared = 1;
  55 static int nb_fds;
  56 static int server_fd;
  57
  58 static void usage(const char *name)
  59 {
  60     (printf) (
  61 "Usage: %s [OPTIONS] FILE\n"
  62 "QEMU Disk Network Block Device Server\n"
  63 "\n"
  64 "  -h, --help                display this help and exit\n"
  65 "  -V, --version             output version information and exit\n"
  66 "\n"
  67 "Connection properties:\n"
  68 "  -p, --port=PORT           port to listen on (default `%d')\n"
  69 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  70 "  -k, --socket=PATH         path to the unix socket\n"
  71 "                            (default '"SOCKET_PATH"')\n"
  72 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  73 "  -t, --persistent          don't exit on the last connection\n"
  74 "  -v, --verbose             display extra debugging information\n"
  75 "\n"
  76 "Exposing part of the image:\n"
  77 "  -o, --offset=OFFSET       offset into the image\n"
  78 "  -P, --partition=NUM       only expose partition NUM\n"
  79 "\n"
  80 #ifdef __linux__
  81 "Kernel NBD client support:\n"
  82 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
  83 "  -d, --disconnect          disconnect the specified device\n"
  84 "\n"
  85 #endif
  86 "\n"
  87 "Block device options:\n"
  88 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
  89 "  -r, --read-only           export read-only\n"
  90 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
  91 "                            file with backing_file=FILE, redirect the write to\n"
  92 "                            the temporary one\n"
  93 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
  94 "                            load an internal snapshot inside FILE and export it\n"
  95 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
  96 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
  97 "                            '[ID_OR_NAME]'\n"
  98 "  -n, --nocache             disable host cache\n"
  99 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
 100 "      --aio=MODE            set AIO mode (native or threads)\n"
 101 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 102 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 103 "\n"
 104 "Report bugs to <qemu-devel@nongnu.org>\n"
 105     , name, NBD_DEFAULT_PORT, "DEVICE");
 106 }
 107
 108 static void version(const char *name)
 109 {
 110     printf(
 111 "%s version 0.0.1\n"
 112 "Written by Anthony Liguori.\n"
 113 "\n"
 114 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
 115 "This is free software; see the source for copying conditions.  There is NO\n"
 116 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 117     , name);
 118 }
 119
 120 struct partition_record
 121 {
 122     uint8_t bootable;
 123     uint8_t start_head;
 124     uint32_t start_cylinder;
 125     uint8_t start_sector;
 126     uint8_t system;
 127     uint8_t end_head;
 128     uint8_t end_cylinder;
 129     uint8_t end_sector;
 130     uint32_t start_sector_abs;
 131     uint32_t nb_sectors_abs;
 132 };
 133
 134 static void read_partition(uint8_t *p, struct partition_record *r)
 135 {
 136     r->bootable = p[0];
 137     r->start_head = p[1];
 138     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 139     r->start_sector = p[2] & 0x3f;
 140     r->system = p[4];
 141     r->end_head = p[5];
 142     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 143     r->end_sector = p[6] & 0x3f;
 144
 145     r->start_sector_abs = le32_to_cpup((uint32_t *)(p +  8));
 146     r->nb_sectors_abs   = le32_to_cpup((uint32_t *)(p + 12));
 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         error_report("error while reading: %s", strerror(-ret));
 160         exit(EXIT_FAILURE);
 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].system || !mbr[i].nb_sectors_abs) {
 171             continue;
 172         }
 173
 174         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 175             struct partition_record ext[4];
 176             uint8_t data1[512];
 177             int j;
 178
 179             if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 0) {
 180                 error_report("error while reading: %s", strerror(-ret));
 181                 exit(EXIT_FAILURE);
 182             }
 183
 184             for (j = 0; j < 4; j++) {
 185                 read_partition(&data1[446 + 16 * j], &ext[j]);
 186                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
 187                     continue;
 188                 }
 189
 190                 if ((ext_partnum + j + 1) == partition) {
 191                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 192                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 193                     return 0;
 194                 }
 195             }
 196             ext_partnum += 4;
 197         } else if ((i + 1) == partition) {
 198             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 199             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 200             return 0;
 201         }
 202     }
 203
 204     return -ENOENT;
 205 }
 206
 207 static void termsig_handler(int signum)
 208 {
 209     state = TERMINATE;
 210     qemu_notify_event();
 211 }
 212
 213
 214 static void *show_parts(void *arg)
 215 {
 216     char *device = arg;
 217     int nbd;
 218
 219     /* linux just needs an open() to trigger
 220      * the partition table update
 221      * but remember to load the module with max_part != 0 :
 222      *     modprobe nbd max_part=63
 223      */
 224     nbd = open(device, O_RDWR);
 225     if (nbd >= 0) {
 226         close(nbd);
 227     }
 228     return NULL;
 229 }
 230
 231 static void *nbd_client_thread(void *arg)
 232 {
 233     char *device = arg;
 234     off_t size;
 235     uint32_t nbdflags;
 236     int fd, sock;
 237     int ret;
 238     pthread_t show_parts_thread;
 239     Error *local_error = NULL;
 240
 241
 242     sock = socket_connect(saddr, &local_error, NULL, NULL);
 243     if (sock < 0) {
 244         error_report_err(local_error);
 245         goto out;
 246     }
 247
 248     ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
 249                                 &size, &local_error);
 250     if (ret < 0) {
 251         if (local_error) {
 252             error_report_err(local_error);
 253         }
 254         goto out_socket;
 255     }
 256
 257     fd = open(device, O_RDWR);
 258     if (fd < 0) {
 259         /* Linux-only, we can use %m in printf.  */
 260         error_report("Failed to open %s: %m", device);
 261         goto out_socket;
 262     }
 263
 264     ret = nbd_init(fd, sock, nbdflags, size);
 265     if (ret < 0) {
 266         goto out_fd;
 267     }
 268
 269     /* update partition table */
 270     pthread_create(&show_parts_thread, NULL, show_parts, device);
 271
 272     if (verbose) {
 273         fprintf(stderr, "NBD device %s is now connected to %s\n",
 274                 device, srcpath);
 275     } else {
 276         /* Close stderr so that the qemu-nbd process exits.  */
 277         dup2(STDOUT_FILENO, STDERR_FILENO);
 278     }
 279
 280     ret = nbd_client(fd);
 281     if (ret) {
 282         goto out_fd;
 283     }
 284     close(fd);
 285     kill(getpid(), SIGTERM);
 286     return (void *) EXIT_SUCCESS;
 287
 288 out_fd:
 289     close(fd);
 290 out_socket:
 291     closesocket(sock);
 292 out:
 293     kill(getpid(), SIGTERM);
 294     return (void *) EXIT_FAILURE;
 295 }
 296
 297 static int nbd_can_accept(void)
 298 {
 299     return nb_fds < shared;
 300 }
 301
 302 static void nbd_export_closed(NBDExport *exp)
 303 {
 304     assert(state == TERMINATING);
 305     state = TERMINATED;
 306 }
 307
 308 static void nbd_update_server_fd_handler(int fd);
 309
 310 static void nbd_client_closed(NBDClient *client)
 311 {
 312     nb_fds--;
 313     if (nb_fds == 0 && !persistent && state == RUNNING) {
 314         state = TERMINATE;
 315     }
 316     nbd_update_server_fd_handler(server_fd);
 317     nbd_client_put(client);
 318 }
 319
 320 static void nbd_accept(void *opaque)
 321 {
 322     struct sockaddr_in addr;
 323     socklen_t addr_len = sizeof(addr);
 324
 325     int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
 326     if (fd < 0) {
 327         perror("accept");
 328         return;
 329     }
 330
 331     if (state >= TERMINATE) {
 332         close(fd);
 333         return;
 334     }
 335
 336     if (nbd_client_new(exp, fd, nbd_client_closed)) {
 337         nb_fds++;
 338         nbd_update_server_fd_handler(server_fd);
 339     } else {
 340         shutdown(fd, 2);
 341         close(fd);
 342     }
 343 }
 344
 345 static void nbd_update_server_fd_handler(int fd)
 346 {
 347     if (nbd_can_accept()) {
 348         qemu_set_fd_handler(fd, nbd_accept, NULL, (void *)(uintptr_t)fd);
 349     } else {
 350         qemu_set_fd_handler(fd, NULL, NULL, NULL);
 351     }
 352 }
 353
 354
 355 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 356                                                const char *bindto,
 357                                                const char *port)
 358 {
 359     SocketAddress *saddr;
 360
 361     saddr = g_new0(SocketAddress, 1);
 362     if (sockpath) {
 363         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
 364         saddr->u.q_unix = g_new0(UnixSocketAddress, 1);
 365         saddr->u.q_unix->path = g_strdup(sockpath);
 366     } else {
 367         saddr->type = SOCKET_ADDRESS_KIND_INET;
 368         saddr->u.inet = g_new0(InetSocketAddress, 1);
 369         saddr->u.inet->host = g_strdup(bindto);
 370         if (port) {
 371             saddr->u.inet->port = g_strdup(port);
 372         } else  {
 373             saddr->u.inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 374         }
 375     }
 376
 377     return saddr;
 378 }
 379
 380
 381 int main(int argc, char **argv)
 382 {
 383     BlockBackend *blk;
 384     BlockDriverState *bs;
 385     off_t dev_offset = 0;
 386     uint32_t nbdflags = 0;
 387     bool disconnect = false;
 388     const char *bindto = "0.0.0.0";
 389     const char *port = NULL;
 390     char *sockpath = NULL;
 391     char *device = NULL;
 392     off_t fd_size;
 393     QemuOpts *sn_opts = NULL;
 394     const char *sn_id_or_name = NULL;
 395     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
 396     struct option lopt[] = {
 397         { "help", 0, NULL, 'h' },
 398         { "version", 0, NULL, 'V' },
 399         { "bind", 1, NULL, 'b' },
 400         { "port", 1, NULL, 'p' },
 401         { "socket", 1, NULL, 'k' },
 402         { "offset", 1, NULL, 'o' },
 403         { "read-only", 0, NULL, 'r' },
 404         { "partition", 1, NULL, 'P' },
 405         { "connect", 1, NULL, 'c' },
 406         { "disconnect", 0, NULL, 'd' },
 407         { "snapshot", 0, NULL, 's' },
 408         { "load-snapshot", 1, NULL, 'l' },
 409         { "nocache", 0, NULL, 'n' },
 410         { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
 411         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 412         { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
 413         { "detect-zeroes", 1, NULL, QEMU_NBD_OPT_DETECT_ZEROES },
 414         { "shared", 1, NULL, 'e' },
 415         { "format", 1, NULL, 'f' },
 416         { "persistent", 0, NULL, 't' },
 417         { "verbose", 0, NULL, 'v' },
 418         { NULL, 0, NULL, 0 }
 419     };
 420     int ch;
 421     int opt_ind = 0;
 422     char *end;
 423     int flags = BDRV_O_RDWR;
 424     int partition = -1;
 425     int ret = 0;
 426     int fd;
 427     bool seen_cache = false;
 428     bool seen_discard = false;
 429     bool seen_aio = false;
 430     pthread_t client_thread;
 431     const char *fmt = NULL;
 432     Error *local_err = NULL;
 433     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 434     QDict *options = NULL;
 435
 436     /* The client thread uses SIGTERM to interrupt the server.  A signal
 437      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 438      */
 439     struct sigaction sa_sigterm;
 440     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 441     sa_sigterm.sa_handler = termsig_handler;
 442     sigaction(SIGTERM, &sa_sigterm, NULL);
 443     qemu_init_exec_dir(argv[0]);
 444
 445     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 446         switch (ch) {
 447         case 's':
 448             flags |= BDRV_O_SNAPSHOT;
 449             break;
 450         case 'n':
 451             optarg = (char *) "none";
 452             /* fallthrough */
 453         case QEMU_NBD_OPT_CACHE:
 454             if (seen_cache) {
 455                 error_report("-n and --cache can only be specified once");
 456                 exit(EXIT_FAILURE);
 457             }
 458             seen_cache = true;
 459             if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
 460                 error_report("Invalid cache mode `%s'", optarg);
 461                 exit(EXIT_FAILURE);
 462             }
 463             break;
 464         case QEMU_NBD_OPT_AIO:
 465             if (seen_aio) {
 466                 error_report("--aio can only be specified once");
 467                 exit(EXIT_FAILURE);
 468             }
 469             seen_aio = true;
 470             if (!strcmp(optarg, "native")) {
 471                 flags |= BDRV_O_NATIVE_AIO;
 472             } else if (!strcmp(optarg, "threads")) {
 473                 /* this is the default */
 474             } else {
 475                error_report("invalid aio mode `%s'", optarg);
 476                exit(EXIT_FAILURE);
 477             }
 478             break;
 479         case QEMU_NBD_OPT_DISCARD:
 480             if (seen_discard) {
 481                 error_report("--discard can only be specified once");
 482                 exit(EXIT_FAILURE);
 483             }
 484             seen_discard = true;
 485             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 486                 error_report("Invalid discard mode `%s'", optarg);
 487                 exit(EXIT_FAILURE);
 488             }
 489             break;
 490         case QEMU_NBD_OPT_DETECT_ZEROES:
 491             detect_zeroes =
 492                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
 493                                 optarg,
 494                                 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
 495                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 496                                 &local_err);
 497             if (local_err) {
 498                 error_reportf_err(local_err,
 499                                   "Failed to parse detect_zeroes mode: ");
 500                 exit(EXIT_FAILURE);
 501             }
 502             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 503                 !(flags & BDRV_O_UNMAP)) {
 504                 error_report("setting detect-zeroes to unmap is not allowed "
 505                              "without setting discard operation to unmap");
 506                 exit(EXIT_FAILURE);
 507             }
 508             break;
 509         case 'b':
 510             bindto = optarg;
 511             break;
 512         case 'p':
 513             port = optarg;
 514             break;
 515         case 'o':
 516                 dev_offset = strtoll (optarg, &end, 0);
 517             if (*end) {
 518                 error_report("Invalid offset `%s'", optarg);
 519                 exit(EXIT_FAILURE);
 520             }
 521             if (dev_offset < 0) {
 522                 error_report("Offset must be positive `%s'", optarg);
 523                 exit(EXIT_FAILURE);
 524             }
 525             break;
 526         case 'l':
 527             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 528                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 529                                                   optarg, false);
 530                 if (!sn_opts) {
 531                     error_report("Failed in parsing snapshot param `%s'",
 532                                  optarg);
 533                     exit(EXIT_FAILURE);
 534                 }
 535             } else {
 536                 sn_id_or_name = optarg;
 537             }
 538             /* fall through */
 539         case 'r':
 540             nbdflags |= NBD_FLAG_READ_ONLY;
 541             flags &= ~BDRV_O_RDWR;
 542             break;
 543         case 'P':
 544             partition = strtol(optarg, &end, 0);
 545             if (*end) {
 546                 error_report("Invalid partition `%s'", optarg);
 547                 exit(EXIT_FAILURE);
 548             }
 549             if (partition < 1 || partition > 8) {
 550                 error_report("Invalid partition %d", partition);
 551                 exit(EXIT_FAILURE);
 552             }
 553             break;
 554         case 'k':
 555             sockpath = optarg;
 556             if (sockpath[0] != '/') {
 557                 error_report("socket path must be absolute");
 558                 exit(EXIT_FAILURE);
 559             }
 560             break;
 561         case 'd':
 562             disconnect = true;
 563             break;
 564         case 'c':
 565             device = optarg;
 566             break;
 567         case 'e':
 568             shared = strtol(optarg, &end, 0);
 569             if (*end) {
 570                 error_report("Invalid shared device number '%s'", optarg);
 571                 exit(EXIT_FAILURE);
 572             }
 573             if (shared < 1) {
 574                 error_report("Shared device number must be greater than 0");
 575                 exit(EXIT_FAILURE);
 576             }
 577             break;
 578         case 'f':
 579             fmt = optarg;
 580             break;
 581         case 't':
 582             persistent = 1;
 583             break;
 584         case 'v':
 585             verbose = 1;
 586             break;
 587         case 'V':
 588             version(argv[0]);
 589             exit(0);
 590             break;
 591         case 'h':
 592             usage(argv[0]);
 593             exit(0);
 594             break;
 595         case '?':
 596             error_report("Try `%s --help' for more information.", argv[0]);
 597             exit(EXIT_FAILURE);
 598         }
 599     }
 600
 601     if ((argc - optind) != 1) {
 602         error_report("Invalid number of arguments");
 603         error_printf("Try `%s --help' for more information.\n", argv[0]);
 604         exit(EXIT_FAILURE);
 605     }
 606
 607     if (disconnect) {
 608         fd = open(argv[optind], O_RDWR);
 609         if (fd < 0) {
 610             error_report("Cannot open %s: %s", argv[optind],
 611                          strerror(errno));
 612             exit(EXIT_FAILURE);
 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             error_report("Error setting up communication pipe: %s",
 630                          strerror(errno));
 631             exit(EXIT_FAILURE);
 632         }
 633
 634         /* Now daemonize, but keep a communication channel open to
 635          * print errors and exit with the proper status code.
 636          */
 637         pid = fork();
 638         if (pid < 0) {
 639             error_report("Failed to fork: %s", strerror(errno));
 640             exit(EXIT_FAILURE);
 641         } else if (pid == 0) {
 642             close(stderr_fd[0]);
 643             ret = qemu_daemon(1, 0);
 644
 645             /* Temporarily redirect stderr to the parent's pipe...  */
 646             dup2(stderr_fd[1], STDERR_FILENO);
 647             if (ret < 0) {
 648                 error_report("Failed to daemonize: %s", strerror(errno));
 649                 exit(EXIT_FAILURE);
 650             }
 651
 652             /* ... close the descriptor we inherited and go on.  */
 653             close(stderr_fd[1]);
 654         } else {
 655             bool errors = false;
 656             char *buf;
 657
 658             /* In the parent.  Print error messages from the child until
 659              * it closes the pipe.
 660              */
 661             close(stderr_fd[1]);
 662             buf = g_malloc(1024);
 663             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 664                 errors = true;
 665                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 666                 if (ret < 0) {
 667                     exit(EXIT_FAILURE);
 668                 }
 669             }
 670             if (ret < 0) {
 671                 error_report("Cannot read from daemon: %s",
 672                              strerror(errno));
 673                 exit(EXIT_FAILURE);
 674             }
 675
 676             /* Usually the daemon should not print any message.
 677              * Exit with zero status in that case.
 678              */
 679             exit(errors);
 680         }
 681     }
 682
 683     if (device != NULL && sockpath == NULL) {
 684         sockpath = g_malloc(128);
 685         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 686     }
 687
 688     saddr = nbd_build_socket_address(sockpath, bindto, port);
 689
 690     if (qemu_init_main_loop(&local_err)) {
 691         error_report_err(local_err);
 692         exit(EXIT_FAILURE);
 693     }
 694     bdrv_init();
 695     atexit(bdrv_close_all);
 696
 697     if (fmt) {
 698         options = qdict_new();
 699         qdict_put(options, "driver", qstring_from_str(fmt));
 700     }
 701
 702     srcpath = argv[optind];
 703     blk = blk_new_open("hda", srcpath, NULL, options, flags, &local_err);
 704     if (!blk) {
 705         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
 706                           argv[optind]);
 707         exit(EXIT_FAILURE);
 708     }
 709     bs = blk_bs(blk);
 710
 711     if (sn_opts) {
 712         ret = bdrv_snapshot_load_tmp(bs,
 713                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 714                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 715                                      &local_err);
 716     } else if (sn_id_or_name) {
 717         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 718                                                    &local_err);
 719     }
 720     if (ret < 0) {
 721         error_reportf_err(local_err, "Failed to load snapshot: ");
 722         exit(EXIT_FAILURE);
 723     }
 724
 725     bs->detect_zeroes = detect_zeroes;
 726     fd_size = blk_getlength(blk);
 727     if (fd_size < 0) {
 728         error_report("Failed to determine the image length: %s",
 729                      strerror(-fd_size));
 730         exit(EXIT_FAILURE);
 731     }
 732
 733     if (partition != -1) {
 734         ret = find_partition(blk, partition, &dev_offset, &fd_size);
 735         if (ret < 0) {
 736             error_report("Could not find partition %d: %s", partition,
 737                          strerror(-ret));
 738             exit(EXIT_FAILURE);
 739         }
 740     }
 741
 742     exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
 743                          &local_err);
 744     if (!exp) {
 745         error_report_err(local_err);
 746         exit(EXIT_FAILURE);
 747     }
 748
 749     fd = socket_listen(saddr, &local_err);
 750     if (fd < 0) {
 751         error_report_err(local_err);
 752         return 1;
 753     }
 754
 755     if (device) {
 756         int ret;
 757
 758         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 759         if (ret != 0) {
 760             error_report("Failed to create client thread: %s", strerror(ret));
 761             exit(EXIT_FAILURE);
 762         }
 763     } else {
 764         /* Shut up GCC warnings.  */
 765         memset(&client_thread, 0, sizeof(client_thread));
 766     }
 767
 768     server_fd = fd;
 769     nbd_update_server_fd_handler(fd);
 770
 771     /* now when the initialization is (almost) complete, chdir("/")
 772      * to free any busy filesystems */
 773     if (chdir("/") < 0) {
 774         error_report("Could not chdir to root directory: %s",
 775                      strerror(errno));
 776         exit(EXIT_FAILURE);
 777     }
 778
 779     state = RUNNING;
 780     do {
 781         main_loop_wait(false);
 782         if (state == TERMINATE) {
 783             state = TERMINATING;
 784             nbd_export_close(exp);
 785             nbd_export_put(exp);
 786             exp = NULL;
 787         }
 788     } while (state != TERMINATED);
 789
 790     blk_unref(blk);
 791     if (sockpath) {
 792         unlink(sockpath);
 793     }
 794
 795     qemu_opts_del(sn_opts);
 796
 797     if (device) {
 798         void *ret;
 799         pthread_join(client_thread, &ret);
 800         exit(ret != NULL);
 801     } else {
 802         exit(EXIT_SUCCESS);
 803     }
 804 }