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/error-report.h"
  26 #include "qemu/config-file.h"
  27 #include "block/snapshot.h"
  28 #include "qapi/util.h"
  29 #include "qapi/qmp/qstring.h"
  30 #include "qom/object_interfaces.h"
  31 #include "io/channel-socket.h"
  32
  33 #include <getopt.h>
  34 #include <sys/types.h>
  35 #include <signal.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 #define QEMU_NBD_OPT_OBJECT        5
  45 #define QEMU_NBD_OPT_TLSCREDS      6
  46 #define QEMU_NBD_OPT_IMAGE_OPTS    7
  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 = g_new0(UnixSocketAddress, 1);
 383         saddr->u.q_unix->path = g_strdup(sockpath);
 384     } else {
 385         saddr->type = SOCKET_ADDRESS_KIND_INET;
 386         saddr->u.inet = g_new0(InetSocketAddress, 1);
 387         saddr->u.inet->host = g_strdup(bindto);
 388         if (port) {
 389             saddr->u.inet->port = g_strdup(port);
 390         } else  {
 391             saddr->u.inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 392         }
 393     }
 394
 395     return saddr;
 396 }
 397
 398
 399 static QemuOptsList file_opts = {
 400     .name = "file",
 401     .implied_opt_name = "file",
 402     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 403     .desc = {
 404         /* no elements => accept any params */
 405         { /* end of list */ }
 406     },
 407 };
 408
 409 static QemuOptsList qemu_object_opts = {
 410     .name = "object",
 411     .implied_opt_name = "qom-type",
 412     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 413     .desc = {
 414         { }
 415     },
 416 };
 417
 418
 419
 420 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 421 {
 422     Object *obj;
 423     QCryptoTLSCreds *creds;
 424
 425     obj = object_resolve_path_component(
 426         object_get_objects_root(), id);
 427     if (!obj) {
 428         error_setg(errp, "No TLS credentials with id '%s'",
 429                    id);
 430         return NULL;
 431     }
 432     creds = (QCryptoTLSCreds *)
 433         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 434     if (!creds) {
 435         error_setg(errp, "Object with id '%s' is not TLS credentials",
 436                    id);
 437         return NULL;
 438     }
 439
 440     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
 441         error_setg(errp,
 442                    "Expecting TLS credentials with a server endpoint");
 443         return NULL;
 444     }
 445     object_ref(obj);
 446     return creds;
 447 }
 448
 449
 450 int main(int argc, char **argv)
 451 {
 452     BlockBackend *blk;
 453     BlockDriverState *bs;
 454     off_t dev_offset = 0;
 455     uint32_t nbdflags = 0;
 456     bool disconnect = false;
 457     const char *bindto = "0.0.0.0";
 458     const char *port = NULL;
 459     char *sockpath = NULL;
 460     char *device = NULL;
 461     off_t fd_size;
 462     QemuOpts *sn_opts = NULL;
 463     const char *sn_id_or_name = NULL;
 464     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:";
 465     struct option lopt[] = {
 466         { "help", 0, NULL, 'h' },
 467         { "version", 0, NULL, 'V' },
 468         { "bind", 1, NULL, 'b' },
 469         { "port", 1, NULL, 'p' },
 470         { "socket", 1, NULL, 'k' },
 471         { "offset", 1, NULL, 'o' },
 472         { "read-only", 0, NULL, 'r' },
 473         { "partition", 1, NULL, 'P' },
 474         { "connect", 1, NULL, 'c' },
 475         { "disconnect", 0, NULL, 'd' },
 476         { "snapshot", 0, NULL, 's' },
 477         { "load-snapshot", 1, NULL, 'l' },
 478         { "nocache", 0, NULL, 'n' },
 479         { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
 480         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 481         { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
 482         { "detect-zeroes", 1, NULL, QEMU_NBD_OPT_DETECT_ZEROES },
 483         { "shared", 1, NULL, 'e' },
 484         { "format", 1, NULL, 'f' },
 485         { "persistent", 0, NULL, 't' },
 486         { "verbose", 0, NULL, 'v' },
 487         { "object", 1, NULL, QEMU_NBD_OPT_OBJECT },
 488         { "export-name", 1, NULL, 'x' },
 489         { "tls-creds", 1, NULL, QEMU_NBD_OPT_TLSCREDS },
 490         { "image-opts", 0, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 491         { NULL, 0, NULL, 0 }
 492     };
 493     int ch;
 494     int opt_ind = 0;
 495     char *end;
 496     int flags = BDRV_O_RDWR;
 497     int partition = -1;
 498     int ret = 0;
 499     bool seen_cache = false;
 500     bool seen_discard = false;
 501     bool seen_aio = false;
 502     pthread_t client_thread;
 503     const char *fmt = NULL;
 504     Error *local_err = NULL;
 505     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 506     QDict *options = NULL;
 507     const char *export_name = NULL;
 508     const char *tlscredsid = NULL;
 509     bool imageOpts = false;
 510
 511     /* The client thread uses SIGTERM to interrupt the server.  A signal
 512      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 513      */
 514     struct sigaction sa_sigterm;
 515     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 516     sa_sigterm.sa_handler = termsig_handler;
 517     sigaction(SIGTERM, &sa_sigterm, NULL);
 518     module_call_init(MODULE_INIT_QOM);
 519     qemu_add_opts(&qemu_object_opts);
 520     qemu_init_exec_dir(argv[0]);
 521
 522     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 523         switch (ch) {
 524         case 's':
 525             flags |= BDRV_O_SNAPSHOT;
 526             break;
 527         case 'n':
 528             optarg = (char *) "none";
 529             /* fallthrough */
 530         case QEMU_NBD_OPT_CACHE:
 531             if (seen_cache) {
 532                 error_report("-n and --cache can only be specified once");
 533                 exit(EXIT_FAILURE);
 534             }
 535             seen_cache = true;
 536             if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
 537                 error_report("Invalid cache mode `%s'", optarg);
 538                 exit(EXIT_FAILURE);
 539             }
 540             break;
 541         case QEMU_NBD_OPT_AIO:
 542             if (seen_aio) {
 543                 error_report("--aio can only be specified once");
 544                 exit(EXIT_FAILURE);
 545             }
 546             seen_aio = true;
 547             if (!strcmp(optarg, "native")) {
 548                 flags |= BDRV_O_NATIVE_AIO;
 549             } else if (!strcmp(optarg, "threads")) {
 550                 /* this is the default */
 551             } else {
 552                error_report("invalid aio mode `%s'", optarg);
 553                exit(EXIT_FAILURE);
 554             }
 555             break;
 556         case QEMU_NBD_OPT_DISCARD:
 557             if (seen_discard) {
 558                 error_report("--discard can only be specified once");
 559                 exit(EXIT_FAILURE);
 560             }
 561             seen_discard = true;
 562             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 563                 error_report("Invalid discard mode `%s'", optarg);
 564                 exit(EXIT_FAILURE);
 565             }
 566             break;
 567         case QEMU_NBD_OPT_DETECT_ZEROES:
 568             detect_zeroes =
 569                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
 570                                 optarg,
 571                                 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
 572                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 573                                 &local_err);
 574             if (local_err) {
 575                 error_reportf_err(local_err,
 576                                   "Failed to parse detect_zeroes mode: ");
 577                 exit(EXIT_FAILURE);
 578             }
 579             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 580                 !(flags & BDRV_O_UNMAP)) {
 581                 error_report("setting detect-zeroes to unmap is not allowed "
 582                              "without setting discard operation to unmap");
 583                 exit(EXIT_FAILURE);
 584             }
 585             break;
 586         case 'b':
 587             bindto = optarg;
 588             break;
 589         case 'p':
 590             port = optarg;
 591             break;
 592         case 'o':
 593                 dev_offset = strtoll (optarg, &end, 0);
 594             if (*end) {
 595                 error_report("Invalid offset `%s'", optarg);
 596                 exit(EXIT_FAILURE);
 597             }
 598             if (dev_offset < 0) {
 599                 error_report("Offset must be positive `%s'", optarg);
 600                 exit(EXIT_FAILURE);
 601             }
 602             break;
 603         case 'l':
 604             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 605                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 606                                                   optarg, false);
 607                 if (!sn_opts) {
 608                     error_report("Failed in parsing snapshot param `%s'",
 609                                  optarg);
 610                     exit(EXIT_FAILURE);
 611                 }
 612             } else {
 613                 sn_id_or_name = optarg;
 614             }
 615             /* fall through */
 616         case 'r':
 617             nbdflags |= NBD_FLAG_READ_ONLY;
 618             flags &= ~BDRV_O_RDWR;
 619             break;
 620         case 'P':
 621             partition = strtol(optarg, &end, 0);
 622             if (*end) {
 623                 error_report("Invalid partition `%s'", optarg);
 624                 exit(EXIT_FAILURE);
 625             }
 626             if (partition < 1 || partition > 8) {
 627                 error_report("Invalid partition %d", partition);
 628                 exit(EXIT_FAILURE);
 629             }
 630             break;
 631         case 'k':
 632             sockpath = optarg;
 633             if (sockpath[0] != '/') {
 634                 error_report("socket path must be absolute");
 635                 exit(EXIT_FAILURE);
 636             }
 637             break;
 638         case 'd':
 639             disconnect = true;
 640             break;
 641         case 'c':
 642             device = optarg;
 643             break;
 644         case 'e':
 645             shared = strtol(optarg, &end, 0);
 646             if (*end) {
 647                 error_report("Invalid shared device number '%s'", optarg);
 648                 exit(EXIT_FAILURE);
 649             }
 650             if (shared < 1) {
 651                 error_report("Shared device number must be greater than 0");
 652                 exit(EXIT_FAILURE);
 653             }
 654             break;
 655         case 'f':
 656             fmt = optarg;
 657             break;
 658         case 't':
 659             persistent = 1;
 660             break;
 661         case 'x':
 662             export_name = optarg;
 663             break;
 664         case 'v':
 665             verbose = 1;
 666             break;
 667         case 'V':
 668             version(argv[0]);
 669             exit(0);
 670             break;
 671         case 'h':
 672             usage(argv[0]);
 673             exit(0);
 674             break;
 675         case '?':
 676             error_report("Try `%s --help' for more information.", argv[0]);
 677             exit(EXIT_FAILURE);
 678         case QEMU_NBD_OPT_OBJECT: {
 679             QemuOpts *opts;
 680             opts = qemu_opts_parse_noisily(&qemu_object_opts,
 681                                            optarg, true);
 682             if (!opts) {
 683                 exit(EXIT_FAILURE);
 684             }
 685         }   break;
 686         case QEMU_NBD_OPT_TLSCREDS:
 687             tlscredsid = optarg;
 688             break;
 689         case QEMU_NBD_OPT_IMAGE_OPTS:
 690             imageOpts = true;
 691             break;
 692         }
 693     }
 694
 695     if ((argc - optind) != 1) {
 696         error_report("Invalid number of arguments");
 697         error_printf("Try `%s --help' for more information.\n", argv[0]);
 698         exit(EXIT_FAILURE);
 699     }
 700
 701     if (qemu_opts_foreach(&qemu_object_opts,
 702                           user_creatable_add_opts_foreach,
 703                           NULL, &local_err)) {
 704         error_report_err(local_err);
 705         exit(EXIT_FAILURE);
 706     }
 707
 708     if (tlscredsid) {
 709         if (sockpath) {
 710             error_report("TLS is only supported with IPv4/IPv6");
 711             exit(EXIT_FAILURE);
 712         }
 713         if (device) {
 714             error_report("TLS is not supported with a host device");
 715             exit(EXIT_FAILURE);
 716         }
 717         if (!export_name) {
 718             /* Set the default NBD protocol export name, since
 719              * we *must* use new style protocol for TLS */
 720             export_name = "";
 721         }
 722         tlscreds = nbd_get_tls_creds(tlscredsid, &local_err);
 723         if (local_err) {
 724             error_report("Failed to get TLS creds %s",
 725                          error_get_pretty(local_err));
 726             exit(EXIT_FAILURE);
 727         }
 728     }
 729
 730     if (disconnect) {
 731         int nbdfd = open(argv[optind], O_RDWR);
 732         if (nbdfd < 0) {
 733             error_report("Cannot open %s: %s", argv[optind],
 734                          strerror(errno));
 735             exit(EXIT_FAILURE);
 736         }
 737         nbd_disconnect(nbdfd);
 738
 739         close(nbdfd);
 740
 741         printf("%s disconnected\n", argv[optind]);
 742
 743         return 0;
 744     }
 745
 746     if (device && !verbose) {
 747         int stderr_fd[2];
 748         pid_t pid;
 749         int ret;
 750
 751         if (qemu_pipe(stderr_fd) < 0) {
 752             error_report("Error setting up communication pipe: %s",
 753                          strerror(errno));
 754             exit(EXIT_FAILURE);
 755         }
 756
 757         /* Now daemonize, but keep a communication channel open to
 758          * print errors and exit with the proper status code.
 759          */
 760         pid = fork();
 761         if (pid < 0) {
 762             error_report("Failed to fork: %s", strerror(errno));
 763             exit(EXIT_FAILURE);
 764         } else if (pid == 0) {
 765             close(stderr_fd[0]);
 766             ret = qemu_daemon(1, 0);
 767
 768             /* Temporarily redirect stderr to the parent's pipe...  */
 769             dup2(stderr_fd[1], STDERR_FILENO);
 770             if (ret < 0) {
 771                 error_report("Failed to daemonize: %s", strerror(errno));
 772                 exit(EXIT_FAILURE);
 773             }
 774
 775             /* ... close the descriptor we inherited and go on.  */
 776             close(stderr_fd[1]);
 777         } else {
 778             bool errors = false;
 779             char *buf;
 780
 781             /* In the parent.  Print error messages from the child until
 782              * it closes the pipe.
 783              */
 784             close(stderr_fd[1]);
 785             buf = g_malloc(1024);
 786             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 787                 errors = true;
 788                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 789                 if (ret < 0) {
 790                     exit(EXIT_FAILURE);
 791                 }
 792             }
 793             if (ret < 0) {
 794                 error_report("Cannot read from daemon: %s",
 795                              strerror(errno));
 796                 exit(EXIT_FAILURE);
 797             }
 798
 799             /* Usually the daemon should not print any message.
 800              * Exit with zero status in that case.
 801              */
 802             exit(errors);
 803         }
 804     }
 805
 806     if (device != NULL && sockpath == NULL) {
 807         sockpath = g_malloc(128);
 808         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 809     }
 810
 811     saddr = nbd_build_socket_address(sockpath, bindto, port);
 812
 813     if (qemu_init_main_loop(&local_err)) {
 814         error_report_err(local_err);
 815         exit(EXIT_FAILURE);
 816     }
 817     bdrv_init();
 818     atexit(bdrv_close_all);
 819
 820     srcpath = argv[optind];
 821     if (imageOpts) {
 822         QemuOpts *opts;
 823         if (fmt) {
 824             error_report("--image-opts and -f are mutually exclusive");
 825             exit(EXIT_FAILURE);
 826         }
 827         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
 828         if (!opts) {
 829             qemu_opts_reset(&file_opts);
 830             exit(EXIT_FAILURE);
 831         }
 832         options = qemu_opts_to_qdict(opts, NULL);
 833         qemu_opts_reset(&file_opts);
 834         blk = blk_new_open("hda", NULL, NULL, options, flags, &local_err);
 835     } else {
 836         if (fmt) {
 837             options = qdict_new();
 838             qdict_put(options, "driver", qstring_from_str(fmt));
 839         }
 840         blk = blk_new_open("hda", srcpath, NULL, options, flags, &local_err);
 841     }
 842
 843     if (!blk) {
 844         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
 845                           argv[optind]);
 846         exit(EXIT_FAILURE);
 847     }
 848     bs = blk_bs(blk);
 849
 850     if (sn_opts) {
 851         ret = bdrv_snapshot_load_tmp(bs,
 852                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 853                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 854                                      &local_err);
 855     } else if (sn_id_or_name) {
 856         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 857                                                    &local_err);
 858     }
 859     if (ret < 0) {
 860         error_reportf_err(local_err, "Failed to load snapshot: ");
 861         exit(EXIT_FAILURE);
 862     }
 863
 864     bs->detect_zeroes = detect_zeroes;
 865     fd_size = blk_getlength(blk);
 866     if (fd_size < 0) {
 867         error_report("Failed to determine the image length: %s",
 868                      strerror(-fd_size));
 869         exit(EXIT_FAILURE);
 870     }
 871
 872     if (partition != -1) {
 873         ret = find_partition(blk, partition, &dev_offset, &fd_size);
 874         if (ret < 0) {
 875             error_report("Could not find partition %d: %s", partition,
 876                          strerror(-ret));
 877             exit(EXIT_FAILURE);
 878         }
 879     }
 880
 881     exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
 882                          &local_err);
 883     if (!exp) {
 884         error_report_err(local_err);
 885         exit(EXIT_FAILURE);
 886     }
 887     if (export_name) {
 888         nbd_export_set_name(exp, export_name);
 889         newproto = true;
 890     }
 891
 892     server_ioc = qio_channel_socket_new();
 893     if (qio_channel_socket_listen_sync(server_ioc, saddr, &local_err) < 0) {
 894         object_unref(OBJECT(server_ioc));
 895         error_report_err(local_err);
 896         return 1;
 897     }
 898
 899     if (device) {
 900         int ret;
 901
 902         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 903         if (ret != 0) {
 904             error_report("Failed to create client thread: %s", strerror(ret));
 905             exit(EXIT_FAILURE);
 906         }
 907     } else {
 908         /* Shut up GCC warnings.  */
 909         memset(&client_thread, 0, sizeof(client_thread));
 910     }
 911
 912     nbd_update_server_watch();
 913
 914     /* now when the initialization is (almost) complete, chdir("/")
 915      * to free any busy filesystems */
 916     if (chdir("/") < 0) {
 917         error_report("Could not chdir to root directory: %s",
 918                      strerror(errno));
 919         exit(EXIT_FAILURE);
 920     }
 921
 922     state = RUNNING;
 923     do {
 924         main_loop_wait(false);
 925         if (state == TERMINATE) {
 926             state = TERMINATING;
 927             nbd_export_close(exp);
 928             nbd_export_put(exp);
 929             exp = NULL;
 930         }
 931     } while (state != TERMINATED);
 932
 933     blk_unref(blk);
 934     if (sockpath) {
 935         unlink(sockpath);
 936     }
 937
 938     qemu_opts_del(sn_opts);
 939
 940     if (device) {
 941         void *ret;
 942         pthread_join(client_thread, &ret);
 943         exit(ret != NULL);
 944     } else {
 945         exit(EXIT_SUCCESS);
 946     }
 947 }