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 <libgen.h>
  35 #include <pthread.h>
  36
  37 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  38 #define QEMU_NBD_OPT_CACHE         256
  39 #define QEMU_NBD_OPT_AIO           257
  40 #define QEMU_NBD_OPT_DISCARD       258
  41 #define QEMU_NBD_OPT_DETECT_ZEROES 259
  42 #define QEMU_NBD_OPT_OBJECT        260
  43 #define QEMU_NBD_OPT_TLSCREDS      261
  44 #define QEMU_NBD_OPT_IMAGE_OPTS    262
  45
  46 static NBDExport *exp;
  47 static bool newproto;
  48 static int verbose;
  49 static char *srcpath;
  50 static SocketAddress *saddr;
  51 static int persistent = 0;
  52 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  53 static int shared = 1;
  54 static int nb_fds;
  55 static QIOChannelSocket *server_ioc;
  56 static int server_watch = -1;
  57 static QCryptoTLSCreds *tlscreds;
  58
  59 static void usage(const char *name)
  60 {
  61     (printf) (
  62 "Usage: %s [OPTIONS] FILE\n"
  63 "QEMU Disk Network Block Device Server\n"
  64 "\n"
  65 "  -h, --help                display this help and exit\n"
  66 "  -V, --version             output version information and exit\n"
  67 "\n"
  68 "Connection properties:\n"
  69 "  -p, --port=PORT           port to listen on (default `%d')\n"
  70 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  71 "  -k, --socket=PATH         path to the unix socket\n"
  72 "                            (default '"SOCKET_PATH"')\n"
  73 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  74 "  -t, --persistent          don't exit on the last connection\n"
  75 "  -v, --verbose             display extra debugging information\n"
  76 "\n"
  77 "Exposing part of the image:\n"
  78 "  -o, --offset=OFFSET       offset into the image\n"
  79 "  -P, --partition=NUM       only expose partition NUM\n"
  80 "\n"
  81 "General purpose options:\n"
  82 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
  83 "                            passwords and/or encryption keys\n"
  84 #ifdef __linux__
  85 "Kernel NBD client support:\n"
  86 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
  87 "  -d, --disconnect          disconnect the specified device\n"
  88 "\n"
  89 #endif
  90 "\n"
  91 "Block device options:\n"
  92 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
  93 "  -r, --read-only           export read-only\n"
  94 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
  95 "                            file with backing_file=FILE, redirect the write to\n"
  96 "                            the temporary one\n"
  97 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
  98 "                            load an internal snapshot inside FILE and export it\n"
  99 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
 100 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 101 "                            '[ID_OR_NAME]'\n"
 102 "  -n, --nocache             disable host cache\n"
 103 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
 104 "      --aio=MODE            set AIO mode (native or threads)\n"
 105 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 106 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 107 "      --image-opts          treat FILE as a full set of image options\n"
 108 "\n"
 109 "Report bugs to <qemu-devel@nongnu.org>\n"
 110     , name, NBD_DEFAULT_PORT, "DEVICE");
 111 }
 112
 113 static void version(const char *name)
 114 {
 115     printf(
 116 "%s version 0.0.1\n"
 117 "Written by Anthony Liguori.\n"
 118 "\n"
 119 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
 120 "This is free software; see the source for copying conditions.  There is NO\n"
 121 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 122     , name);
 123 }
 124
 125 struct partition_record
 126 {
 127     uint8_t bootable;
 128     uint8_t start_head;
 129     uint32_t start_cylinder;
 130     uint8_t start_sector;
 131     uint8_t system;
 132     uint8_t end_head;
 133     uint8_t end_cylinder;
 134     uint8_t end_sector;
 135     uint32_t start_sector_abs;
 136     uint32_t nb_sectors_abs;
 137 };
 138
 139 static void read_partition(uint8_t *p, struct partition_record *r)
 140 {
 141     r->bootable = p[0];
 142     r->start_head = p[1];
 143     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 144     r->start_sector = p[2] & 0x3f;
 145     r->system = p[4];
 146     r->end_head = p[5];
 147     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 148     r->end_sector = p[6] & 0x3f;
 149
 150     r->start_sector_abs = le32_to_cpup((uint32_t *)(p +  8));
 151     r->nb_sectors_abs   = le32_to_cpup((uint32_t *)(p + 12));
 152 }
 153
 154 static int find_partition(BlockBackend *blk, int partition,
 155                           off_t *offset, off_t *size)
 156 {
 157     struct partition_record mbr[4];
 158     uint8_t data[512];
 159     int i;
 160     int ext_partnum = 4;
 161     int ret;
 162
 163     if ((ret = blk_read(blk, 0, data, 1)) < 0) {
 164         error_report("error while reading: %s", strerror(-ret));
 165         exit(EXIT_FAILURE);
 166     }
 167
 168     if (data[510] != 0x55 || data[511] != 0xaa) {
 169         return -EINVAL;
 170     }
 171
 172     for (i = 0; i < 4; i++) {
 173         read_partition(&data[446 + 16 * i], &mbr[i]);
 174
 175         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
 176             continue;
 177         }
 178
 179         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 180             struct partition_record ext[4];
 181             uint8_t data1[512];
 182             int j;
 183
 184             if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 0) {
 185                 error_report("error while reading: %s", strerror(-ret));
 186                 exit(EXIT_FAILURE);
 187             }
 188
 189             for (j = 0; j < 4; j++) {
 190                 read_partition(&data1[446 + 16 * j], &ext[j]);
 191                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
 192                     continue;
 193                 }
 194
 195                 if ((ext_partnum + j + 1) == partition) {
 196                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 197                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 198                     return 0;
 199                 }
 200             }
 201             ext_partnum += 4;
 202         } else if ((i + 1) == partition) {
 203             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 204             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 205             return 0;
 206         }
 207     }
 208
 209     return -ENOENT;
 210 }
 211
 212 static void termsig_handler(int signum)
 213 {
 214     state = TERMINATE;
 215     qemu_notify_event();
 216 }
 217
 218
 219 static void *show_parts(void *arg)
 220 {
 221     char *device = arg;
 222     int nbd;
 223
 224     /* linux just needs an open() to trigger
 225      * the partition table update
 226      * but remember to load the module with max_part != 0 :
 227      *     modprobe nbd max_part=63
 228      */
 229     nbd = open(device, O_RDWR);
 230     if (nbd >= 0) {
 231         close(nbd);
 232     }
 233     return NULL;
 234 }
 235
 236 static void *nbd_client_thread(void *arg)
 237 {
 238     char *device = arg;
 239     off_t size;
 240     uint32_t nbdflags;
 241     QIOChannelSocket *sioc;
 242     int fd;
 243     int ret;
 244     pthread_t show_parts_thread;
 245     Error *local_error = NULL;
 246
 247     sioc = qio_channel_socket_new();
 248     if (qio_channel_socket_connect_sync(sioc,
 249                                         saddr,
 250                                         &local_error) < 0) {
 251         error_report_err(local_error);
 252         goto out;
 253     }
 254
 255     ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), NULL, &nbdflags,
 256                                 NULL, NULL, NULL,
 257                                 &size, &local_error);
 258     if (ret < 0) {
 259         if (local_error) {
 260             error_report_err(local_error);
 261         }
 262         goto out_socket;
 263     }
 264
 265     fd = open(device, O_RDWR);
 266     if (fd < 0) {
 267         /* Linux-only, we can use %m in printf.  */
 268         error_report("Failed to open %s: %m", device);
 269         goto out_socket;
 270     }
 271
 272     ret = nbd_init(fd, sioc, nbdflags, size);
 273     if (ret < 0) {
 274         goto out_fd;
 275     }
 276
 277     /* update partition table */
 278     pthread_create(&show_parts_thread, NULL, show_parts, device);
 279
 280     if (verbose) {
 281         fprintf(stderr, "NBD device %s is now connected to %s\n",
 282                 device, srcpath);
 283     } else {
 284         /* Close stderr so that the qemu-nbd process exits.  */
 285         dup2(STDOUT_FILENO, STDERR_FILENO);
 286     }
 287
 288     ret = nbd_client(fd);
 289     if (ret) {
 290         goto out_fd;
 291     }
 292     close(fd);
 293     object_unref(OBJECT(sioc));
 294     kill(getpid(), SIGTERM);
 295     return (void *) EXIT_SUCCESS;
 296
 297 out_fd:
 298     close(fd);
 299 out_socket:
 300     object_unref(OBJECT(sioc));
 301 out:
 302     kill(getpid(), SIGTERM);
 303     return (void *) EXIT_FAILURE;
 304 }
 305
 306 static int nbd_can_accept(void)
 307 {
 308     return nb_fds < shared;
 309 }
 310
 311 static void nbd_export_closed(NBDExport *exp)
 312 {
 313     assert(state == TERMINATING);
 314     state = TERMINATED;
 315 }
 316
 317 static void nbd_update_server_watch(void);
 318
 319 static void nbd_client_closed(NBDClient *client)
 320 {
 321     nb_fds--;
 322     if (nb_fds == 0 && !persistent && state == RUNNING) {
 323         state = TERMINATE;
 324     }
 325     nbd_update_server_watch();
 326     nbd_client_put(client);
 327 }
 328
 329 static gboolean nbd_accept(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
 330 {
 331     QIOChannelSocket *cioc;
 332
 333     cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
 334                                      NULL);
 335     if (!cioc) {
 336         return TRUE;
 337     }
 338
 339     if (state >= TERMINATE) {
 340         object_unref(OBJECT(cioc));
 341         return TRUE;
 342     }
 343
 344     nb_fds++;
 345     nbd_update_server_watch();
 346     nbd_client_new(newproto ? NULL : exp, cioc,
 347                    tlscreds, NULL, nbd_client_closed);
 348     object_unref(OBJECT(cioc));
 349
 350     return TRUE;
 351 }
 352
 353 static void nbd_update_server_watch(void)
 354 {
 355     if (nbd_can_accept()) {
 356         if (server_watch == -1) {
 357             server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
 358                                                  G_IO_IN,
 359                                                  nbd_accept,
 360                                                  NULL, NULL);
 361         }
 362     } else {
 363         if (server_watch != -1) {
 364             g_source_remove(server_watch);
 365             server_watch = -1;
 366         }
 367     }
 368 }
 369
 370
 371 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 372                                                const char *bindto,
 373                                                const char *port)
 374 {
 375     SocketAddress *saddr;
 376
 377     saddr = g_new0(SocketAddress, 1);
 378     if (sockpath) {
 379         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
 380         saddr->u.q_unix.data = g_new0(UnixSocketAddress, 1);
 381         saddr->u.q_unix.data->path = g_strdup(sockpath);
 382     } else {
 383         InetSocketAddress *inet;
 384         saddr->type = SOCKET_ADDRESS_KIND_INET;
 385         inet = saddr->u.inet.data = g_new0(InetSocketAddress, 1);
 386         inet->host = g_strdup(bindto);
 387         if (port) {
 388             inet->port = g_strdup(port);
 389         } else  {
 390             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 391         }
 392     }
 393
 394     return saddr;
 395 }
 396
 397
 398 static QemuOptsList file_opts = {
 399     .name = "file",
 400     .implied_opt_name = "file",
 401     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 402     .desc = {
 403         /* no elements => accept any params */
 404         { /* end of list */ }
 405     },
 406 };
 407
 408 static QemuOptsList qemu_object_opts = {
 409     .name = "object",
 410     .implied_opt_name = "qom-type",
 411     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 412     .desc = {
 413         { }
 414     },
 415 };
 416
 417
 418
 419 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 420 {
 421     Object *obj;
 422     QCryptoTLSCreds *creds;
 423
 424     obj = object_resolve_path_component(
 425         object_get_objects_root(), id);
 426     if (!obj) {
 427         error_setg(errp, "No TLS credentials with id '%s'",
 428                    id);
 429         return NULL;
 430     }
 431     creds = (QCryptoTLSCreds *)
 432         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 433     if (!creds) {
 434         error_setg(errp, "Object with id '%s' is not TLS credentials",
 435                    id);
 436         return NULL;
 437     }
 438
 439     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
 440         error_setg(errp,
 441                    "Expecting TLS credentials with a server endpoint");
 442         return NULL;
 443     }
 444     object_ref(obj);
 445     return creds;
 446 }
 447
 448
 449 int main(int argc, char **argv)
 450 {
 451     BlockBackend *blk;
 452     BlockDriverState *bs;
 453     off_t dev_offset = 0;
 454     uint32_t nbdflags = 0;
 455     bool disconnect = false;
 456     const char *bindto = "0.0.0.0";
 457     const char *port = NULL;
 458     char *sockpath = NULL;
 459     char *device = NULL;
 460     off_t fd_size;
 461     QemuOpts *sn_opts = NULL;
 462     const char *sn_id_or_name = NULL;
 463     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:";
 464     struct option lopt[] = {
 465         { "help", no_argument, NULL, 'h' },
 466         { "version", no_argument, NULL, 'V' },
 467         { "bind", required_argument, NULL, 'b' },
 468         { "port", required_argument, NULL, 'p' },
 469         { "socket", required_argument, NULL, 'k' },
 470         { "offset", required_argument, NULL, 'o' },
 471         { "read-only", no_argument, NULL, 'r' },
 472         { "partition", required_argument, NULL, 'P' },
 473         { "connect", required_argument, NULL, 'c' },
 474         { "disconnect", no_argument, NULL, 'd' },
 475         { "snapshot", no_argument, NULL, 's' },
 476         { "load-snapshot", required_argument, NULL, 'l' },
 477         { "nocache", no_argument, NULL, 'n' },
 478         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 479         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 480         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 481         { "detect-zeroes", required_argument, NULL,
 482           QEMU_NBD_OPT_DETECT_ZEROES },
 483         { "shared", required_argument, NULL, 'e' },
 484         { "format", required_argument, NULL, 'f' },
 485         { "persistent", no_argument, NULL, 't' },
 486         { "verbose", no_argument, NULL, 'v' },
 487         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 488         { "export-name", required_argument, NULL, 'x' },
 489         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 490         { "image-opts", no_argument, 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(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(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 }