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/osdep.h"
  20 #include "qemu-common.h"
  21 #include "sysemu/block-backend.h"
  22 #include "block/block_int.h"
  23 #include "block/nbd.h"
  24 #include "qemu/main-loop.h"
  25 #include "qemu/sockets.h"
  26 #include "qemu/error-report.h"
  27 #include "block/snapshot.h"
  28 #include "qapi/util.h"
  29 #include "qapi/qmp/qstring.h"
  30
  31 #include <getopt.h>
  32 #include <sys/socket.h>
  33 #include <netinet/in.h>
  34 #include <netinet/tcp.h>
  35 #include <arpa/inet.h>
  36 #include <libgen.h>
  37 #include <pthread.h>
  38
  39 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  40 #define QEMU_NBD_OPT_CACHE         1
  41 #define QEMU_NBD_OPT_AIO           2
  42 #define QEMU_NBD_OPT_DISCARD       3
  43 #define QEMU_NBD_OPT_DETECT_ZEROES 4
  44
  45 static NBDExport *exp;
  46 static int verbose;
  47 static char *srcpath;
  48 static SocketAddress *saddr;
  49 static int persistent = 0;
  50 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  51 static int shared = 1;
  52 static int nb_fds;
  53 static int server_fd;
  54
  55 static void usage(const char *name)
  56 {
  57     (printf) (
  58 "Usage: %s [OPTIONS] FILE\n"
  59 "QEMU Disk Network Block Device Server\n"
  60 "\n"
  61 "  -h, --help                display this help and exit\n"
  62 "  -V, --version             output version information and exit\n"
  63 "\n"
  64 "Connection properties:\n"
  65 "  -p, --port=PORT           port to listen on (default `%d')\n"
  66 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  67 "  -k, --socket=PATH         path to the unix socket\n"
  68 "                            (default '"SOCKET_PATH"')\n"
  69 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  70 "  -t, --persistent          don't exit on the last connection\n"
  71 "  -v, --verbose             display extra debugging information\n"
  72 "\n"
  73 "Exposing part of the image:\n"
  74 "  -o, --offset=OFFSET       offset into the image\n"
  75 "  -P, --partition=NUM       only expose partition NUM\n"
  76 "\n"
  77 #ifdef __linux__
  78 "Kernel NBD client support:\n"
  79 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
  80 "  -d, --disconnect          disconnect the specified device\n"
  81 "\n"
  82 #endif
  83 "\n"
  84 "Block device options:\n"
  85 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
  86 "  -r, --read-only           export read-only\n"
  87 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
  88 "                            file with backing_file=FILE, redirect the write to\n"
  89 "                            the temporary one\n"
  90 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
  91 "                            load an internal snapshot inside FILE and export it\n"
  92 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
  93 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
  94 "                            '[ID_OR_NAME]'\n"
  95 "  -n, --nocache             disable host cache\n"
  96 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
  97 "      --aio=MODE            set AIO mode (native or threads)\n"
  98 "      --discard=MODE        set discard mode (ignore, unmap)\n"
  99 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 100 "\n"
 101 "Report bugs to <qemu-devel@nongnu.org>\n"
 102     , name, NBD_DEFAULT_PORT, "DEVICE");
 103 }
 104
 105 static void version(const char *name)
 106 {
 107     printf(
 108 "%s version 0.0.1\n"
 109 "Written by Anthony Liguori.\n"
 110 "\n"
 111 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
 112 "This is free software; see the source for copying conditions.  There is NO\n"
 113 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 114     , name);
 115 }
 116
 117 struct partition_record
 118 {
 119     uint8_t bootable;
 120     uint8_t start_head;
 121     uint32_t start_cylinder;
 122     uint8_t start_sector;
 123     uint8_t system;
 124     uint8_t end_head;
 125     uint8_t end_cylinder;
 126     uint8_t end_sector;
 127     uint32_t start_sector_abs;
 128     uint32_t nb_sectors_abs;
 129 };
 130
 131 static void read_partition(uint8_t *p, struct partition_record *r)
 132 {
 133     r->bootable = p[0];
 134     r->start_head = p[1];
 135     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 136     r->start_sector = p[2] & 0x3f;
 137     r->system = p[4];
 138     r->end_head = p[5];
 139     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 140     r->end_sector = p[6] & 0x3f;
 141
 142     r->start_sector_abs = le32_to_cpup((uint32_t *)(p +  8));
 143     r->nb_sectors_abs   = le32_to_cpup((uint32_t *)(p + 12));
 144 }
 145
 146 static int find_partition(BlockBackend *blk, int partition,
 147                           off_t *offset, off_t *size)
 148 {
 149     struct partition_record mbr[4];
 150     uint8_t data[512];
 151     int i;
 152     int ext_partnum = 4;
 153     int ret;
 154
 155     if ((ret = blk_read(blk, 0, data, 1)) < 0) {
 156         error_report("error while reading: %s", strerror(-ret));
 157         exit(EXIT_FAILURE);
 158     }
 159
 160     if (data[510] != 0x55 || data[511] != 0xaa) {
 161         return -EINVAL;
 162     }
 163
 164     for (i = 0; i < 4; i++) {
 165         read_partition(&data[446 + 16 * i], &mbr[i]);
 166
 167         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
 168             continue;
 169         }
 170
 171         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 172             struct partition_record ext[4];
 173             uint8_t data1[512];
 174             int j;
 175
 176             if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 0) {
 177                 error_report("error while reading: %s", strerror(-ret));
 178                 exit(EXIT_FAILURE);
 179             }
 180
 181             for (j = 0; j < 4; j++) {
 182                 read_partition(&data1[446 + 16 * j], &ext[j]);
 183                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
 184                     continue;
 185                 }
 186
 187                 if ((ext_partnum + j + 1) == partition) {
 188                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 189                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 190                     return 0;
 191                 }
 192             }
 193             ext_partnum += 4;
 194         } else if ((i + 1) == partition) {
 195             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 196             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 197             return 0;
 198         }
 199     }
 200
 201     return -ENOENT;
 202 }
 203
 204 static void termsig_handler(int signum)
 205 {
 206     state = TERMINATE;
 207     qemu_notify_event();
 208 }
 209
 210
 211 static void *show_parts(void *arg)
 212 {
 213     char *device = arg;
 214     int nbd;
 215
 216     /* linux just needs an open() to trigger
 217      * the partition table update
 218      * but remember to load the module with max_part != 0 :
 219      *     modprobe nbd max_part=63
 220      */
 221     nbd = open(device, O_RDWR);
 222     if (nbd >= 0) {
 223         close(nbd);
 224     }
 225     return NULL;
 226 }
 227
 228 static void *nbd_client_thread(void *arg)
 229 {
 230     char *device = arg;
 231     off_t size;
 232     uint32_t nbdflags;
 233     int fd, sock;
 234     int ret;
 235     pthread_t show_parts_thread;
 236     Error *local_error = NULL;
 237
 238
 239     sock = socket_connect(saddr, &local_error, NULL, NULL);
 240     if (sock < 0) {
 241         error_report_err(local_error);
 242         goto out;
 243     }
 244
 245     ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
 246                                 &size, &local_error);
 247     if (ret < 0) {
 248         if (local_error) {
 249             error_report_err(local_error);
 250         }
 251         goto out_socket;
 252     }
 253
 254     fd = open(device, O_RDWR);
 255     if (fd < 0) {
 256         /* Linux-only, we can use %m in printf.  */
 257         error_report("Failed to open %s: %m", device);
 258         goto out_socket;
 259     }
 260
 261     ret = nbd_init(fd, sock, nbdflags, size);
 262     if (ret < 0) {
 263         goto out_fd;
 264     }
 265
 266     /* update partition table */
 267     pthread_create(&show_parts_thread, NULL, show_parts, device);
 268
 269     if (verbose) {
 270         fprintf(stderr, "NBD device %s is now connected to %s\n",
 271                 device, srcpath);
 272     } else {
 273         /* Close stderr so that the qemu-nbd process exits.  */
 274         dup2(STDOUT_FILENO, STDERR_FILENO);
 275     }
 276
 277     ret = nbd_client(fd);
 278     if (ret) {
 279         goto out_fd;
 280     }
 281     close(fd);
 282     kill(getpid(), SIGTERM);
 283     return (void *) EXIT_SUCCESS;
 284
 285 out_fd:
 286     close(fd);
 287 out_socket:
 288     closesocket(sock);
 289 out:
 290     kill(getpid(), SIGTERM);
 291     return (void *) EXIT_FAILURE;
 292 }
 293
 294 static int nbd_can_accept(void)
 295 {
 296     return nb_fds < shared;
 297 }
 298
 299 static void nbd_export_closed(NBDExport *exp)
 300 {
 301     assert(state == TERMINATING);
 302     state = TERMINATED;
 303 }
 304
 305 static void nbd_update_server_fd_handler(int fd);
 306
 307 static void nbd_client_closed(NBDClient *client)
 308 {
 309     nb_fds--;
 310     if (nb_fds == 0 && !persistent && state == RUNNING) {
 311         state = TERMINATE;
 312     }
 313     nbd_update_server_fd_handler(server_fd);
 314     nbd_client_put(client);
 315 }
 316
 317 static void nbd_accept(void *opaque)
 318 {
 319     struct sockaddr_in addr;
 320     socklen_t addr_len = sizeof(addr);
 321
 322     int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
 323     if (fd < 0) {
 324         perror("accept");
 325         return;
 326     }
 327
 328     if (state >= TERMINATE) {
 329         close(fd);
 330         return;
 331     }
 332
 333     nb_fds++;
 334     nbd_update_server_fd_handler(server_fd);
 335     nbd_client_new(exp, fd, nbd_client_closed);
 336 }
 337
 338 static void nbd_update_server_fd_handler(int fd)
 339 {
 340     if (nbd_can_accept()) {
 341         qemu_set_fd_handler(fd, nbd_accept, NULL, (void *)(uintptr_t)fd);
 342     } else {
 343         qemu_set_fd_handler(fd, NULL, NULL, NULL);
 344     }
 345 }
 346
 347
 348 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 349                                                const char *bindto,
 350                                                const char *port)
 351 {
 352     SocketAddress *saddr;
 353
 354     saddr = g_new0(SocketAddress, 1);
 355     if (sockpath) {
 356         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
 357         saddr->u.q_unix = g_new0(UnixSocketAddress, 1);
 358         saddr->u.q_unix->path = g_strdup(sockpath);
 359     } else {
 360         saddr->type = SOCKET_ADDRESS_KIND_INET;
 361         saddr->u.inet = g_new0(InetSocketAddress, 1);
 362         saddr->u.inet->host = g_strdup(bindto);
 363         if (port) {
 364             saddr->u.inet->port = g_strdup(port);
 365         } else  {
 366             saddr->u.inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 367         }
 368     }
 369
 370     return saddr;
 371 }
 372
 373
 374 int main(int argc, char **argv)
 375 {
 376     BlockBackend *blk;
 377     BlockDriverState *bs;
 378     off_t dev_offset = 0;
 379     uint32_t nbdflags = 0;
 380     bool disconnect = false;
 381     const char *bindto = "0.0.0.0";
 382     const char *port = NULL;
 383     char *sockpath = NULL;
 384     char *device = NULL;
 385     off_t fd_size;
 386     QemuOpts *sn_opts = NULL;
 387     const char *sn_id_or_name = NULL;
 388     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
 389     struct option lopt[] = {
 390         { "help", 0, NULL, 'h' },
 391         { "version", 0, NULL, 'V' },
 392         { "bind", 1, NULL, 'b' },
 393         { "port", 1, NULL, 'p' },
 394         { "socket", 1, NULL, 'k' },
 395         { "offset", 1, NULL, 'o' },
 396         { "read-only", 0, NULL, 'r' },
 397         { "partition", 1, NULL, 'P' },
 398         { "connect", 1, NULL, 'c' },
 399         { "disconnect", 0, NULL, 'd' },
 400         { "snapshot", 0, NULL, 's' },
 401         { "load-snapshot", 1, NULL, 'l' },
 402         { "nocache", 0, NULL, 'n' },
 403         { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
 404         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 405         { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
 406         { "detect-zeroes", 1, NULL, QEMU_NBD_OPT_DETECT_ZEROES },
 407         { "shared", 1, NULL, 'e' },
 408         { "format", 1, NULL, 'f' },
 409         { "persistent", 0, NULL, 't' },
 410         { "verbose", 0, NULL, 'v' },
 411         { NULL, 0, NULL, 0 }
 412     };
 413     int ch;
 414     int opt_ind = 0;
 415     char *end;
 416     int flags = BDRV_O_RDWR;
 417     int partition = -1;
 418     int ret = 0;
 419     int fd;
 420     bool seen_cache = false;
 421     bool seen_discard = false;
 422     bool seen_aio = false;
 423     pthread_t client_thread;
 424     const char *fmt = NULL;
 425     Error *local_err = NULL;
 426     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 427     QDict *options = NULL;
 428
 429     /* The client thread uses SIGTERM to interrupt the server.  A signal
 430      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 431      */
 432     struct sigaction sa_sigterm;
 433     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 434     sa_sigterm.sa_handler = termsig_handler;
 435     sigaction(SIGTERM, &sa_sigterm, NULL);
 436     qemu_init_exec_dir(argv[0]);
 437
 438     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 439         switch (ch) {
 440         case 's':
 441             flags |= BDRV_O_SNAPSHOT;
 442             break;
 443         case 'n':
 444             optarg = (char *) "none";
 445             /* fallthrough */
 446         case QEMU_NBD_OPT_CACHE:
 447             if (seen_cache) {
 448                 error_report("-n and --cache can only be specified once");
 449                 exit(EXIT_FAILURE);
 450             }
 451             seen_cache = true;
 452             if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
 453                 error_report("Invalid cache mode `%s'", optarg);
 454                 exit(EXIT_FAILURE);
 455             }
 456             break;
 457         case QEMU_NBD_OPT_AIO:
 458             if (seen_aio) {
 459                 error_report("--aio can only be specified once");
 460                 exit(EXIT_FAILURE);
 461             }
 462             seen_aio = true;
 463             if (!strcmp(optarg, "native")) {
 464                 flags |= BDRV_O_NATIVE_AIO;
 465             } else if (!strcmp(optarg, "threads")) {
 466                 /* this is the default */
 467             } else {
 468                error_report("invalid aio mode `%s'", optarg);
 469                exit(EXIT_FAILURE);
 470             }
 471             break;
 472         case QEMU_NBD_OPT_DISCARD:
 473             if (seen_discard) {
 474                 error_report("--discard can only be specified once");
 475                 exit(EXIT_FAILURE);
 476             }
 477             seen_discard = true;
 478             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 479                 error_report("Invalid discard mode `%s'", optarg);
 480                 exit(EXIT_FAILURE);
 481             }
 482             break;
 483         case QEMU_NBD_OPT_DETECT_ZEROES:
 484             detect_zeroes =
 485                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
 486                                 optarg,
 487                                 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
 488                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 489                                 &local_err);
 490             if (local_err) {
 491                 error_reportf_err(local_err,
 492                                   "Failed to parse detect_zeroes mode: ");
 493                 exit(EXIT_FAILURE);
 494             }
 495             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 496                 !(flags & BDRV_O_UNMAP)) {
 497                 error_report("setting detect-zeroes to unmap is not allowed "
 498                              "without setting discard operation to unmap");
 499                 exit(EXIT_FAILURE);
 500             }
 501             break;
 502         case 'b':
 503             bindto = optarg;
 504             break;
 505         case 'p':
 506             port = optarg;
 507             break;
 508         case 'o':
 509                 dev_offset = strtoll (optarg, &end, 0);
 510             if (*end) {
 511                 error_report("Invalid offset `%s'", optarg);
 512                 exit(EXIT_FAILURE);
 513             }
 514             if (dev_offset < 0) {
 515                 error_report("Offset must be positive `%s'", optarg);
 516                 exit(EXIT_FAILURE);
 517             }
 518             break;
 519         case 'l':
 520             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 521                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 522                                                   optarg, false);
 523                 if (!sn_opts) {
 524                     error_report("Failed in parsing snapshot param `%s'",
 525                                  optarg);
 526                     exit(EXIT_FAILURE);
 527                 }
 528             } else {
 529                 sn_id_or_name = optarg;
 530             }
 531             /* fall through */
 532         case 'r':
 533             nbdflags |= NBD_FLAG_READ_ONLY;
 534             flags &= ~BDRV_O_RDWR;
 535             break;
 536         case 'P':
 537             partition = strtol(optarg, &end, 0);
 538             if (*end) {
 539                 error_report("Invalid partition `%s'", optarg);
 540                 exit(EXIT_FAILURE);
 541             }
 542             if (partition < 1 || partition > 8) {
 543                 error_report("Invalid partition %d", partition);
 544                 exit(EXIT_FAILURE);
 545             }
 546             break;
 547         case 'k':
 548             sockpath = optarg;
 549             if (sockpath[0] != '/') {
 550                 error_report("socket path must be absolute");
 551                 exit(EXIT_FAILURE);
 552             }
 553             break;
 554         case 'd':
 555             disconnect = true;
 556             break;
 557         case 'c':
 558             device = optarg;
 559             break;
 560         case 'e':
 561             shared = strtol(optarg, &end, 0);
 562             if (*end) {
 563                 error_report("Invalid shared device number '%s'", optarg);
 564                 exit(EXIT_FAILURE);
 565             }
 566             if (shared < 1) {
 567                 error_report("Shared device number must be greater than 0");
 568                 exit(EXIT_FAILURE);
 569             }
 570             break;
 571         case 'f':
 572             fmt = optarg;
 573             break;
 574         case 't':
 575             persistent = 1;
 576             break;
 577         case 'v':
 578             verbose = 1;
 579             break;
 580         case 'V':
 581             version(argv[0]);
 582             exit(0);
 583             break;
 584         case 'h':
 585             usage(argv[0]);
 586             exit(0);
 587             break;
 588         case '?':
 589             error_report("Try `%s --help' for more information.", argv[0]);
 590             exit(EXIT_FAILURE);
 591         }
 592     }
 593
 594     if ((argc - optind) != 1) {
 595         error_report("Invalid number of arguments");
 596         error_printf("Try `%s --help' for more information.\n", argv[0]);
 597         exit(EXIT_FAILURE);
 598     }
 599
 600     if (disconnect) {
 601         fd = open(argv[optind], O_RDWR);
 602         if (fd < 0) {
 603             error_report("Cannot open %s: %s", argv[optind],
 604                          strerror(errno));
 605             exit(EXIT_FAILURE);
 606         }
 607         nbd_disconnect(fd);
 608
 609         close(fd);
 610
 611         printf("%s disconnected\n", argv[optind]);
 612
 613         return 0;
 614     }
 615
 616     if (device && !verbose) {
 617         int stderr_fd[2];
 618         pid_t pid;
 619         int ret;
 620
 621         if (qemu_pipe(stderr_fd) < 0) {
 622             error_report("Error setting up communication pipe: %s",
 623                          strerror(errno));
 624             exit(EXIT_FAILURE);
 625         }
 626
 627         /* Now daemonize, but keep a communication channel open to
 628          * print errors and exit with the proper status code.
 629          */
 630         pid = fork();
 631         if (pid < 0) {
 632             error_report("Failed to fork: %s", strerror(errno));
 633             exit(EXIT_FAILURE);
 634         } else if (pid == 0) {
 635             close(stderr_fd[0]);
 636             ret = qemu_daemon(1, 0);
 637
 638             /* Temporarily redirect stderr to the parent's pipe...  */
 639             dup2(stderr_fd[1], STDERR_FILENO);
 640             if (ret < 0) {
 641                 error_report("Failed to daemonize: %s", strerror(errno));
 642                 exit(EXIT_FAILURE);
 643             }
 644
 645             /* ... close the descriptor we inherited and go on.  */
 646             close(stderr_fd[1]);
 647         } else {
 648             bool errors = false;
 649             char *buf;
 650
 651             /* In the parent.  Print error messages from the child until
 652              * it closes the pipe.
 653              */
 654             close(stderr_fd[1]);
 655             buf = g_malloc(1024);
 656             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 657                 errors = true;
 658                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 659                 if (ret < 0) {
 660                     exit(EXIT_FAILURE);
 661                 }
 662             }
 663             if (ret < 0) {
 664                 error_report("Cannot read from daemon: %s",
 665                              strerror(errno));
 666                 exit(EXIT_FAILURE);
 667             }
 668
 669             /* Usually the daemon should not print any message.
 670              * Exit with zero status in that case.
 671              */
 672             exit(errors);
 673         }
 674     }
 675
 676     if (device != NULL && sockpath == NULL) {
 677         sockpath = g_malloc(128);
 678         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 679     }
 680
 681     saddr = nbd_build_socket_address(sockpath, bindto, port);
 682
 683     if (qemu_init_main_loop(&local_err)) {
 684         error_report_err(local_err);
 685         exit(EXIT_FAILURE);
 686     }
 687     bdrv_init();
 688     atexit(bdrv_close_all);
 689
 690     if (fmt) {
 691         options = qdict_new();
 692         qdict_put(options, "driver", qstring_from_str(fmt));
 693     }
 694
 695     srcpath = argv[optind];
 696     blk = blk_new_open("hda", srcpath, NULL, options, flags, &local_err);
 697     if (!blk) {
 698         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
 699                           argv[optind]);
 700         exit(EXIT_FAILURE);
 701     }
 702     bs = blk_bs(blk);
 703
 704     if (sn_opts) {
 705         ret = bdrv_snapshot_load_tmp(bs,
 706                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 707                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 708                                      &local_err);
 709     } else if (sn_id_or_name) {
 710         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 711                                                    &local_err);
 712     }
 713     if (ret < 0) {
 714         error_reportf_err(local_err, "Failed to load snapshot: ");
 715         exit(EXIT_FAILURE);
 716     }
 717
 718     bs->detect_zeroes = detect_zeroes;
 719     fd_size = blk_getlength(blk);
 720     if (fd_size < 0) {
 721         error_report("Failed to determine the image length: %s",
 722                      strerror(-fd_size));
 723         exit(EXIT_FAILURE);
 724     }
 725
 726     if (partition != -1) {
 727         ret = find_partition(blk, partition, &dev_offset, &fd_size);
 728         if (ret < 0) {
 729             error_report("Could not find partition %d: %s", partition,
 730                          strerror(-ret));
 731             exit(EXIT_FAILURE);
 732         }
 733     }
 734
 735     exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
 736                          &local_err);
 737     if (!exp) {
 738         error_report_err(local_err);
 739         exit(EXIT_FAILURE);
 740     }
 741
 742     fd = socket_listen(saddr, &local_err);
 743     if (fd < 0) {
 744         error_report_err(local_err);
 745         return 1;
 746     }
 747
 748     if (device) {
 749         int ret;
 750
 751         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 752         if (ret != 0) {
 753             error_report("Failed to create client thread: %s", strerror(ret));
 754             exit(EXIT_FAILURE);
 755         }
 756     } else {
 757         /* Shut up GCC warnings.  */
 758         memset(&client_thread, 0, sizeof(client_thread));
 759     }
 760
 761     server_fd = fd;
 762     nbd_update_server_fd_handler(fd);
 763
 764     /* now when the initialization is (almost) complete, chdir("/")
 765      * to free any busy filesystems */
 766     if (chdir("/") < 0) {
 767         error_report("Could not chdir to root directory: %s",
 768                      strerror(errno));
 769         exit(EXIT_FAILURE);
 770     }
 771
 772     state = RUNNING;
 773     do {
 774         main_loop_wait(false);
 775         if (state == TERMINATE) {
 776             state = TERMINATING;
 777             nbd_export_close(exp);
 778             nbd_export_put(exp);
 779             exp = NULL;
 780         }
 781     } while (state != TERMINATED);
 782
 783     blk_unref(blk);
 784     if (sockpath) {
 785         unlink(sockpath);
 786     }
 787
 788     qemu_opts_del(sn_opts);
 789
 790     if (device) {
 791         void *ret;
 792         pthread_join(client_thread, &ret);
 793         exit(ret != NULL);
 794     } else {
 795         exit(EXIT_SUCCESS);
 796     }
 797 }