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 "qapi/error.h"
  21 #include "qemu-common.h"
  22 #include "qemu/cutils.h"
  23 #include "sysemu/block-backend.h"
  24 #include "block/block_int.h"
  25 #include "block/nbd.h"
  26 #include "qemu/main-loop.h"
  27 #include "qemu/error-report.h"
  28 #include "qemu/config-file.h"
  29 #include "block/snapshot.h"
  30 #include "qapi/util.h"
  31 #include "qapi/qmp/qstring.h"
  32 #include "qom/object_interfaces.h"
  33 #include "io/channel-socket.h"
  34
  35 #include <getopt.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         256
  41 #define QEMU_NBD_OPT_AIO           257
  42 #define QEMU_NBD_OPT_DISCARD       258
  43 #define QEMU_NBD_OPT_DETECT_ZEROES 259
  44 #define QEMU_NBD_OPT_OBJECT        260
  45 #define QEMU_NBD_OPT_TLSCREDS      261
  46 #define QEMU_NBD_OPT_IMAGE_OPTS    262
  47
  48 static NBDExport *exp;
  49 static bool newproto;
  50 static int verbose;
  51 static char *srcpath;
  52 static SocketAddress *saddr;
  53 static int persistent = 0;
  54 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  55 static int shared = 1;
  56 static int nb_fds;
  57 static QIOChannelSocket *server_ioc;
  58 static int server_watch = -1;
  59 static QCryptoTLSCreds *tlscreds;
  60
  61 static void usage(const char *name)
  62 {
  63     (printf) (
  64 "Usage: %s [OPTIONS] FILE\n"
  65 "QEMU Disk Network Block Device Server\n"
  66 "\n"
  67 "  -h, --help                display this help and exit\n"
  68 "  -V, --version             output version information and exit\n"
  69 "\n"
  70 "Connection properties:\n"
  71 "  -p, --port=PORT           port to listen on (default `%d')\n"
  72 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  73 "  -k, --socket=PATH         path to the unix socket\n"
  74 "                            (default '"SOCKET_PATH"')\n"
  75 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  76 "  -t, --persistent          don't exit on the last connection\n"
  77 "  -v, --verbose             display extra debugging information\n"
  78 "\n"
  79 "Exposing part of the image:\n"
  80 "  -o, --offset=OFFSET       offset into the image\n"
  81 "  -P, --partition=NUM       only expose partition NUM\n"
  82 "\n"
  83 "General purpose options:\n"
  84 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
  85 "                            passwords and/or encryption keys\n"
  86 #ifdef __linux__
  87 "Kernel NBD client support:\n"
  88 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
  89 "  -d, --disconnect          disconnect the specified device\n"
  90 "\n"
  91 #endif
  92 "\n"
  93 "Block device options:\n"
  94 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
  95 "  -r, --read-only           export read-only\n"
  96 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
  97 "                            file with backing_file=FILE, redirect the write to\n"
  98 "                            the temporary one\n"
  99 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 100 "                            load an internal snapshot inside FILE and export it\n"
 101 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
 102 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 103 "                            '[ID_OR_NAME]'\n"
 104 "  -n, --nocache             disable host cache\n"
 105 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
 106 "      --aio=MODE            set AIO mode (native or threads)\n"
 107 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 108 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 109 "      --image-opts          treat FILE as a full set of image options\n"
 110 "\n"
 111 "Report bugs to <qemu-devel@nongnu.org>\n"
 112     , name, NBD_DEFAULT_PORT, "DEVICE");
 113 }
 114
 115 static void version(const char *name)
 116 {
 117     printf(
 118 "%s version 0.0.1\n"
 119 "Written by Anthony Liguori.\n"
 120 "\n"
 121 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
 122 "This is free software; see the source for copying conditions.  There is NO\n"
 123 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 124     , name);
 125 }
 126
 127 struct partition_record
 128 {
 129     uint8_t bootable;
 130     uint8_t start_head;
 131     uint32_t start_cylinder;
 132     uint8_t start_sector;
 133     uint8_t system;
 134     uint8_t end_head;
 135     uint8_t end_cylinder;
 136     uint8_t end_sector;
 137     uint32_t start_sector_abs;
 138     uint32_t nb_sectors_abs;
 139 };
 140
 141 static void read_partition(uint8_t *p, struct partition_record *r)
 142 {
 143     r->bootable = p[0];
 144     r->start_head = p[1];
 145     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 146     r->start_sector = p[2] & 0x3f;
 147     r->system = p[4];
 148     r->end_head = p[5];
 149     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 150     r->end_sector = p[6] & 0x3f;
 151
 152     r->start_sector_abs = le32_to_cpup((uint32_t *)(p +  8));
 153     r->nb_sectors_abs   = le32_to_cpup((uint32_t *)(p + 12));
 154 }
 155
 156 static int find_partition(BlockBackend *blk, int partition,
 157                           off_t *offset, off_t *size)
 158 {
 159     struct partition_record mbr[4];
 160     uint8_t data[512];
 161     int i;
 162     int ext_partnum = 4;
 163     int ret;
 164
 165     if ((ret = blk_read(blk, 0, data, 1)) < 0) {
 166         error_report("error while reading: %s", strerror(-ret));
 167         exit(EXIT_FAILURE);
 168     }
 169
 170     if (data[510] != 0x55 || data[511] != 0xaa) {
 171         return -EINVAL;
 172     }
 173
 174     for (i = 0; i < 4; i++) {
 175         read_partition(&data[446 + 16 * i], &mbr[i]);
 176
 177         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
 178             continue;
 179         }
 180
 181         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 182             struct partition_record ext[4];
 183             uint8_t data1[512];
 184             int j;
 185
 186             if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 0) {
 187                 error_report("error while reading: %s", strerror(-ret));
 188                 exit(EXIT_FAILURE);
 189             }
 190
 191             for (j = 0; j < 4; j++) {
 192                 read_partition(&data1[446 + 16 * j], &ext[j]);
 193                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
 194                     continue;
 195                 }
 196
 197                 if ((ext_partnum + j + 1) == partition) {
 198                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 199                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 200                     return 0;
 201                 }
 202             }
 203             ext_partnum += 4;
 204         } else if ((i + 1) == partition) {
 205             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 206             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 207             return 0;
 208         }
 209     }
 210
 211     return -ENOENT;
 212 }
 213
 214 static void termsig_handler(int signum)
 215 {
 216     state = TERMINATE;
 217     qemu_notify_event();
 218 }
 219
 220
 221 static void *show_parts(void *arg)
 222 {
 223     char *device = arg;
 224     int nbd;
 225
 226     /* linux just needs an open() to trigger
 227      * the partition table update
 228      * but remember to load the module with max_part != 0 :
 229      *     modprobe nbd max_part=63
 230      */
 231     nbd = open(device, O_RDWR);
 232     if (nbd >= 0) {
 233         close(nbd);
 234     }
 235     return NULL;
 236 }
 237
 238 static void *nbd_client_thread(void *arg)
 239 {
 240     char *device = arg;
 241     off_t size;
 242     uint32_t nbdflags;
 243     QIOChannelSocket *sioc;
 244     int fd;
 245     int ret;
 246     pthread_t show_parts_thread;
 247     Error *local_error = NULL;
 248
 249     sioc = qio_channel_socket_new();
 250     if (qio_channel_socket_connect_sync(sioc,
 251                                         saddr,
 252                                         &local_error) < 0) {
 253         error_report_err(local_error);
 254         goto out;
 255     }
 256
 257     ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), NULL, &nbdflags,
 258                                 NULL, NULL, NULL,
 259                                 &size, &local_error);
 260     if (ret < 0) {
 261         if (local_error) {
 262             error_report_err(local_error);
 263         }
 264         goto out_socket;
 265     }
 266
 267     fd = open(device, O_RDWR);
 268     if (fd < 0) {
 269         /* Linux-only, we can use %m in printf.  */
 270         error_report("Failed to open %s: %m", device);
 271         goto out_socket;
 272     }
 273
 274     ret = nbd_init(fd, sioc, nbdflags, size);
 275     if (ret < 0) {
 276         goto out_fd;
 277     }
 278
 279     /* update partition table */
 280     pthread_create(&show_parts_thread, NULL, show_parts, device);
 281
 282     if (verbose) {
 283         fprintf(stderr, "NBD device %s is now connected to %s\n",
 284                 device, srcpath);
 285     } else {
 286         /* Close stderr so that the qemu-nbd process exits.  */
 287         dup2(STDOUT_FILENO, STDERR_FILENO);
 288     }
 289
 290     ret = nbd_client(fd);
 291     if (ret) {
 292         goto out_fd;
 293     }
 294     close(fd);
 295     object_unref(OBJECT(sioc));
 296     kill(getpid(), SIGTERM);
 297     return (void *) EXIT_SUCCESS;
 298
 299 out_fd:
 300     close(fd);
 301 out_socket:
 302     object_unref(OBJECT(sioc));
 303 out:
 304     kill(getpid(), SIGTERM);
 305     return (void *) EXIT_FAILURE;
 306 }
 307
 308 static int nbd_can_accept(void)
 309 {
 310     return nb_fds < shared;
 311 }
 312
 313 static void nbd_export_closed(NBDExport *exp)
 314 {
 315     assert(state == TERMINATING);
 316     state = TERMINATED;
 317 }
 318
 319 static void nbd_update_server_watch(void);
 320
 321 static void nbd_client_closed(NBDClient *client)
 322 {
 323     nb_fds--;
 324     if (nb_fds == 0 && !persistent && state == RUNNING) {
 325         state = TERMINATE;
 326     }
 327     nbd_update_server_watch();
 328     nbd_client_put(client);
 329 }
 330
 331 static gboolean nbd_accept(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
 332 {
 333     QIOChannelSocket *cioc;
 334
 335     cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
 336                                      NULL);
 337     if (!cioc) {
 338         return TRUE;
 339     }
 340
 341     if (state >= TERMINATE) {
 342         object_unref(OBJECT(cioc));
 343         return TRUE;
 344     }
 345
 346     nb_fds++;
 347     nbd_update_server_watch();
 348     nbd_client_new(newproto ? NULL : exp, cioc,
 349                    tlscreds, NULL, nbd_client_closed);
 350     object_unref(OBJECT(cioc));
 351
 352     return TRUE;
 353 }
 354
 355 static void nbd_update_server_watch(void)
 356 {
 357     if (nbd_can_accept()) {
 358         if (server_watch == -1) {
 359             server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
 360                                                  G_IO_IN,
 361                                                  nbd_accept,
 362                                                  NULL, NULL);
 363         }
 364     } else {
 365         if (server_watch != -1) {
 366             g_source_remove(server_watch);
 367             server_watch = -1;
 368         }
 369     }
 370 }
 371
 372
 373 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 374                                                const char *bindto,
 375                                                const char *port)
 376 {
 377     SocketAddress *saddr;
 378
 379     saddr = g_new0(SocketAddress, 1);
 380     if (sockpath) {
 381         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
 382         saddr->u.q_unix.data = g_new0(UnixSocketAddress, 1);
 383         saddr->u.q_unix.data->path = g_strdup(sockpath);
 384     } else {
 385         InetSocketAddress *inet;
 386         saddr->type = SOCKET_ADDRESS_KIND_INET;
 387         inet = saddr->u.inet.data = g_new0(InetSocketAddress, 1);
 388         inet->host = g_strdup(bindto);
 389         if (port) {
 390             inet->port = g_strdup(port);
 391         } else  {
 392             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 393         }
 394     }
 395
 396     return saddr;
 397 }
 398
 399
 400 static QemuOptsList file_opts = {
 401     .name = "file",
 402     .implied_opt_name = "file",
 403     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 404     .desc = {
 405         /* no elements => accept any params */
 406         { /* end of list */ }
 407     },
 408 };
 409
 410 static QemuOptsList qemu_object_opts = {
 411     .name = "object",
 412     .implied_opt_name = "qom-type",
 413     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 414     .desc = {
 415         { }
 416     },
 417 };
 418
 419
 420
 421 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 422 {
 423     Object *obj;
 424     QCryptoTLSCreds *creds;
 425
 426     obj = object_resolve_path_component(
 427         object_get_objects_root(), id);
 428     if (!obj) {
 429         error_setg(errp, "No TLS credentials with id '%s'",
 430                    id);
 431         return NULL;
 432     }
 433     creds = (QCryptoTLSCreds *)
 434         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 435     if (!creds) {
 436         error_setg(errp, "Object with id '%s' is not TLS credentials",
 437                    id);
 438         return NULL;
 439     }
 440
 441     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
 442         error_setg(errp,
 443                    "Expecting TLS credentials with a server endpoint");
 444         return NULL;
 445     }
 446     object_ref(obj);
 447     return creds;
 448 }
 449
 450
 451 int main(int argc, char **argv)
 452 {
 453     BlockBackend *blk;
 454     BlockDriverState *bs;
 455     off_t dev_offset = 0;
 456     uint32_t nbdflags = 0;
 457     bool disconnect = false;
 458     const char *bindto = "0.0.0.0";
 459     const char *port = NULL;
 460     char *sockpath = NULL;
 461     char *device = NULL;
 462     off_t fd_size;
 463     QemuOpts *sn_opts = NULL;
 464     const char *sn_id_or_name = NULL;
 465     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:";
 466     struct option lopt[] = {
 467         { "help", no_argument, NULL, 'h' },
 468         { "version", no_argument, NULL, 'V' },
 469         { "bind", required_argument, NULL, 'b' },
 470         { "port", required_argument, NULL, 'p' },
 471         { "socket", required_argument, NULL, 'k' },
 472         { "offset", required_argument, NULL, 'o' },
 473         { "read-only", no_argument, NULL, 'r' },
 474         { "partition", required_argument, NULL, 'P' },
 475         { "connect", required_argument, NULL, 'c' },
 476         { "disconnect", no_argument, NULL, 'd' },
 477         { "snapshot", no_argument, NULL, 's' },
 478         { "load-snapshot", required_argument, NULL, 'l' },
 479         { "nocache", no_argument, NULL, 'n' },
 480         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 481         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 482         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 483         { "detect-zeroes", required_argument, NULL,
 484           QEMU_NBD_OPT_DETECT_ZEROES },
 485         { "shared", required_argument, NULL, 'e' },
 486         { "format", required_argument, NULL, 'f' },
 487         { "persistent", no_argument, NULL, 't' },
 488         { "verbose", no_argument, NULL, 'v' },
 489         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 490         { "export-name", required_argument, NULL, 'x' },
 491         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 492         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 493         { NULL, 0, NULL, 0 }
 494     };
 495     int ch;
 496     int opt_ind = 0;
 497     char *end;
 498     int flags = BDRV_O_RDWR;
 499     int partition = -1;
 500     int ret = 0;
 501     bool seen_cache = false;
 502     bool seen_discard = false;
 503     bool seen_aio = false;
 504     pthread_t client_thread;
 505     const char *fmt = NULL;
 506     Error *local_err = NULL;
 507     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 508     QDict *options = NULL;
 509     const char *export_name = NULL;
 510     const char *tlscredsid = NULL;
 511     bool imageOpts = false;
 512     bool writethrough = true;
 513
 514     /* The client thread uses SIGTERM to interrupt the server.  A signal
 515      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 516      */
 517     struct sigaction sa_sigterm;
 518     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 519     sa_sigterm.sa_handler = termsig_handler;
 520     sigaction(SIGTERM, &sa_sigterm, NULL);
 521     module_call_init(MODULE_INIT_QOM);
 522     qemu_add_opts(&qemu_object_opts);
 523     qemu_init_exec_dir(argv[0]);
 524
 525     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 526         switch (ch) {
 527         case 's':
 528             flags |= BDRV_O_SNAPSHOT;
 529             break;
 530         case 'n':
 531             optarg = (char *) "none";
 532             /* fallthrough */
 533         case QEMU_NBD_OPT_CACHE:
 534             if (seen_cache) {
 535                 error_report("-n and --cache can only be specified once");
 536                 exit(EXIT_FAILURE);
 537             }
 538             seen_cache = true;
 539             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 540                 error_report("Invalid cache mode `%s'", optarg);
 541                 exit(EXIT_FAILURE);
 542             }
 543             break;
 544         case QEMU_NBD_OPT_AIO:
 545             if (seen_aio) {
 546                 error_report("--aio can only be specified once");
 547                 exit(EXIT_FAILURE);
 548             }
 549             seen_aio = true;
 550             if (!strcmp(optarg, "native")) {
 551                 flags |= BDRV_O_NATIVE_AIO;
 552             } else if (!strcmp(optarg, "threads")) {
 553                 /* this is the default */
 554             } else {
 555                error_report("invalid aio mode `%s'", optarg);
 556                exit(EXIT_FAILURE);
 557             }
 558             break;
 559         case QEMU_NBD_OPT_DISCARD:
 560             if (seen_discard) {
 561                 error_report("--discard can only be specified once");
 562                 exit(EXIT_FAILURE);
 563             }
 564             seen_discard = true;
 565             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 566                 error_report("Invalid discard mode `%s'", optarg);
 567                 exit(EXIT_FAILURE);
 568             }
 569             break;
 570         case QEMU_NBD_OPT_DETECT_ZEROES:
 571             detect_zeroes =
 572                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
 573                                 optarg,
 574                                 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
 575                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 576                                 &local_err);
 577             if (local_err) {
 578                 error_reportf_err(local_err,
 579                                   "Failed to parse detect_zeroes mode: ");
 580                 exit(EXIT_FAILURE);
 581             }
 582             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 583                 !(flags & BDRV_O_UNMAP)) {
 584                 error_report("setting detect-zeroes to unmap is not allowed "
 585                              "without setting discard operation to unmap");
 586                 exit(EXIT_FAILURE);
 587             }
 588             break;
 589         case 'b':
 590             bindto = optarg;
 591             break;
 592         case 'p':
 593             port = optarg;
 594             break;
 595         case 'o':
 596                 dev_offset = strtoll (optarg, &end, 0);
 597             if (*end) {
 598                 error_report("Invalid offset `%s'", optarg);
 599                 exit(EXIT_FAILURE);
 600             }
 601             if (dev_offset < 0) {
 602                 error_report("Offset must be positive `%s'", optarg);
 603                 exit(EXIT_FAILURE);
 604             }
 605             break;
 606         case 'l':
 607             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 608                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 609                                                   optarg, false);
 610                 if (!sn_opts) {
 611                     error_report("Failed in parsing snapshot param `%s'",
 612                                  optarg);
 613                     exit(EXIT_FAILURE);
 614                 }
 615             } else {
 616                 sn_id_or_name = optarg;
 617             }
 618             /* fall through */
 619         case 'r':
 620             nbdflags |= NBD_FLAG_READ_ONLY;
 621             flags &= ~BDRV_O_RDWR;
 622             break;
 623         case 'P':
 624             partition = strtol(optarg, &end, 0);
 625             if (*end) {
 626                 error_report("Invalid partition `%s'", optarg);
 627                 exit(EXIT_FAILURE);
 628             }
 629             if (partition < 1 || partition > 8) {
 630                 error_report("Invalid partition %d", partition);
 631                 exit(EXIT_FAILURE);
 632             }
 633             break;
 634         case 'k':
 635             sockpath = optarg;
 636             if (sockpath[0] != '/') {
 637                 error_report("socket path must be absolute");
 638                 exit(EXIT_FAILURE);
 639             }
 640             break;
 641         case 'd':
 642             disconnect = true;
 643             break;
 644         case 'c':
 645             device = optarg;
 646             break;
 647         case 'e':
 648             shared = strtol(optarg, &end, 0);
 649             if (*end) {
 650                 error_report("Invalid shared device number '%s'", optarg);
 651                 exit(EXIT_FAILURE);
 652             }
 653             if (shared < 1) {
 654                 error_report("Shared device number must be greater than 0");
 655                 exit(EXIT_FAILURE);
 656             }
 657             break;
 658         case 'f':
 659             fmt = optarg;
 660             break;
 661         case 't':
 662             persistent = 1;
 663             break;
 664         case 'x':
 665             export_name = optarg;
 666             break;
 667         case 'v':
 668             verbose = 1;
 669             break;
 670         case 'V':
 671             version(argv[0]);
 672             exit(0);
 673             break;
 674         case 'h':
 675             usage(argv[0]);
 676             exit(0);
 677             break;
 678         case '?':
 679             error_report("Try `%s --help' for more information.", argv[0]);
 680             exit(EXIT_FAILURE);
 681         case QEMU_NBD_OPT_OBJECT: {
 682             QemuOpts *opts;
 683             opts = qemu_opts_parse_noisily(&qemu_object_opts,
 684                                            optarg, true);
 685             if (!opts) {
 686                 exit(EXIT_FAILURE);
 687             }
 688         }   break;
 689         case QEMU_NBD_OPT_TLSCREDS:
 690             tlscredsid = optarg;
 691             break;
 692         case QEMU_NBD_OPT_IMAGE_OPTS:
 693             imageOpts = true;
 694             break;
 695         }
 696     }
 697
 698     if ((argc - optind) != 1) {
 699         error_report("Invalid number of arguments");
 700         error_printf("Try `%s --help' for more information.\n", argv[0]);
 701         exit(EXIT_FAILURE);
 702     }
 703
 704     if (qemu_opts_foreach(&qemu_object_opts,
 705                           user_creatable_add_opts_foreach,
 706                           NULL, &local_err)) {
 707         error_report_err(local_err);
 708         exit(EXIT_FAILURE);
 709     }
 710
 711     if (tlscredsid) {
 712         if (sockpath) {
 713             error_report("TLS is only supported with IPv4/IPv6");
 714             exit(EXIT_FAILURE);
 715         }
 716         if (device) {
 717             error_report("TLS is not supported with a host device");
 718             exit(EXIT_FAILURE);
 719         }
 720         if (!export_name) {
 721             /* Set the default NBD protocol export name, since
 722              * we *must* use new style protocol for TLS */
 723             export_name = "";
 724         }
 725         tlscreds = nbd_get_tls_creds(tlscredsid, &local_err);
 726         if (local_err) {
 727             error_report("Failed to get TLS creds %s",
 728                          error_get_pretty(local_err));
 729             exit(EXIT_FAILURE);
 730         }
 731     }
 732
 733     if (disconnect) {
 734         int nbdfd = open(argv[optind], O_RDWR);
 735         if (nbdfd < 0) {
 736             error_report("Cannot open %s: %s", argv[optind],
 737                          strerror(errno));
 738             exit(EXIT_FAILURE);
 739         }
 740         nbd_disconnect(nbdfd);
 741
 742         close(nbdfd);
 743
 744         printf("%s disconnected\n", argv[optind]);
 745
 746         return 0;
 747     }
 748
 749     if (device && !verbose) {
 750         int stderr_fd[2];
 751         pid_t pid;
 752         int ret;
 753
 754         if (qemu_pipe(stderr_fd) < 0) {
 755             error_report("Error setting up communication pipe: %s",
 756                          strerror(errno));
 757             exit(EXIT_FAILURE);
 758         }
 759
 760         /* Now daemonize, but keep a communication channel open to
 761          * print errors and exit with the proper status code.
 762          */
 763         pid = fork();
 764         if (pid < 0) {
 765             error_report("Failed to fork: %s", strerror(errno));
 766             exit(EXIT_FAILURE);
 767         } else if (pid == 0) {
 768             close(stderr_fd[0]);
 769             ret = qemu_daemon(1, 0);
 770
 771             /* Temporarily redirect stderr to the parent's pipe...  */
 772             dup2(stderr_fd[1], STDERR_FILENO);
 773             if (ret < 0) {
 774                 error_report("Failed to daemonize: %s", strerror(errno));
 775                 exit(EXIT_FAILURE);
 776             }
 777
 778             /* ... close the descriptor we inherited and go on.  */
 779             close(stderr_fd[1]);
 780         } else {
 781             bool errors = false;
 782             char *buf;
 783
 784             /* In the parent.  Print error messages from the child until
 785              * it closes the pipe.
 786              */
 787             close(stderr_fd[1]);
 788             buf = g_malloc(1024);
 789             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 790                 errors = true;
 791                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 792                 if (ret < 0) {
 793                     exit(EXIT_FAILURE);
 794                 }
 795             }
 796             if (ret < 0) {
 797                 error_report("Cannot read from daemon: %s",
 798                              strerror(errno));
 799                 exit(EXIT_FAILURE);
 800             }
 801
 802             /* Usually the daemon should not print any message.
 803              * Exit with zero status in that case.
 804              */
 805             exit(errors);
 806         }
 807     }
 808
 809     if (device != NULL && sockpath == NULL) {
 810         sockpath = g_malloc(128);
 811         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 812     }
 813
 814     saddr = nbd_build_socket_address(sockpath, bindto, port);
 815
 816     if (qemu_init_main_loop(&local_err)) {
 817         error_report_err(local_err);
 818         exit(EXIT_FAILURE);
 819     }
 820     bdrv_init();
 821     atexit(bdrv_close_all);
 822
 823     srcpath = argv[optind];
 824     if (imageOpts) {
 825         QemuOpts *opts;
 826         if (fmt) {
 827             error_report("--image-opts and -f are mutually exclusive");
 828             exit(EXIT_FAILURE);
 829         }
 830         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
 831         if (!opts) {
 832             qemu_opts_reset(&file_opts);
 833             exit(EXIT_FAILURE);
 834         }
 835         options = qemu_opts_to_qdict(opts, NULL);
 836         qemu_opts_reset(&file_opts);
 837         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
 838     } else {
 839         if (fmt) {
 840             options = qdict_new();
 841             qdict_put(options, "driver", qstring_from_str(fmt));
 842         }
 843         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
 844     }
 845
 846     if (!blk) {
 847         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
 848                           argv[optind]);
 849         exit(EXIT_FAILURE);
 850     }
 851     bs = blk_bs(blk);
 852
 853     blk_set_enable_write_cache(blk, !writethrough);
 854
 855     if (sn_opts) {
 856         ret = bdrv_snapshot_load_tmp(bs,
 857                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 858                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 859                                      &local_err);
 860     } else if (sn_id_or_name) {
 861         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 862                                                    &local_err);
 863     }
 864     if (ret < 0) {
 865         error_reportf_err(local_err, "Failed to load snapshot: ");
 866         exit(EXIT_FAILURE);
 867     }
 868
 869     bs->detect_zeroes = detect_zeroes;
 870     fd_size = blk_getlength(blk);
 871     if (fd_size < 0) {
 872         error_report("Failed to determine the image length: %s",
 873                      strerror(-fd_size));
 874         exit(EXIT_FAILURE);
 875     }
 876
 877     if (partition != -1) {
 878         ret = find_partition(blk, partition, &dev_offset, &fd_size);
 879         if (ret < 0) {
 880             error_report("Could not find partition %d: %s", partition,
 881                          strerror(-ret));
 882             exit(EXIT_FAILURE);
 883         }
 884     }
 885
 886     exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
 887                          &local_err);
 888     if (!exp) {
 889         error_report_err(local_err);
 890         exit(EXIT_FAILURE);
 891     }
 892     if (export_name) {
 893         nbd_export_set_name(exp, export_name);
 894         newproto = true;
 895     }
 896
 897     server_ioc = qio_channel_socket_new();
 898     if (qio_channel_socket_listen_sync(server_ioc, saddr, &local_err) < 0) {
 899         object_unref(OBJECT(server_ioc));
 900         error_report_err(local_err);
 901         return 1;
 902     }
 903
 904     if (device) {
 905         int ret;
 906
 907         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 908         if (ret != 0) {
 909             error_report("Failed to create client thread: %s", strerror(ret));
 910             exit(EXIT_FAILURE);
 911         }
 912     } else {
 913         /* Shut up GCC warnings.  */
 914         memset(&client_thread, 0, sizeof(client_thread));
 915     }
 916
 917     nbd_update_server_watch();
 918
 919     /* now when the initialization is (almost) complete, chdir("/")
 920      * to free any busy filesystems */
 921     if (chdir("/") < 0) {
 922         error_report("Could not chdir to root directory: %s",
 923                      strerror(errno));
 924         exit(EXIT_FAILURE);
 925     }
 926
 927     state = RUNNING;
 928     do {
 929         main_loop_wait(false);
 930         if (state == TERMINATE) {
 931             state = TERMINATING;
 932             nbd_export_close(exp);
 933             nbd_export_put(exp);
 934             exp = NULL;
 935         }
 936     } while (state != TERMINATED);
 937
 938     blk_unref(blk);
 939     if (sockpath) {
 940         unlink(sockpath);
 941     }
 942
 943     qemu_opts_del(sn_opts);
 944
 945     if (device) {
 946         void *ret;
 947         pthread_join(client_thread, &ret);
 948         exit(ret != NULL);
 949     } else {
 950         exit(EXIT_SUCCESS);
 951     }
 952 }