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 "qemu/bswap.h"
  30 #include "block/snapshot.h"
  31 #include "qapi/util.h"
  32 #include "qapi/qmp/qstring.h"
  33 #include "qom/object_interfaces.h"
  34 #include "io/channel-socket.h"
  35 #include "crypto/init.h"
  36
  37 #include <getopt.h>
  38 #include <libgen.h>
  39 #include <pthread.h>
  40
  41 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  42 #define QEMU_NBD_OPT_CACHE         256
  43 #define QEMU_NBD_OPT_AIO           257
  44 #define QEMU_NBD_OPT_DISCARD       258
  45 #define QEMU_NBD_OPT_DETECT_ZEROES 259
  46 #define QEMU_NBD_OPT_OBJECT        260
  47 #define QEMU_NBD_OPT_TLSCREDS      261
  48 #define QEMU_NBD_OPT_IMAGE_OPTS    262
  49
  50 #define MBR_SIZE 512
  51
  52 static NBDExport *exp;
  53 static bool newproto;
  54 static int verbose;
  55 static char *srcpath;
  56 static SocketAddress *saddr;
  57 static int persistent = 0;
  58 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  59 static int shared = 1;
  60 static int nb_fds;
  61 static QIOChannelSocket *server_ioc;
  62 static int server_watch = -1;
  63 static QCryptoTLSCreds *tlscreds;
  64
  65 static void usage(const char *name)
  66 {
  67     (printf) (
  68 "Usage: %s [OPTIONS] FILE\n"
  69 "QEMU Disk Network Block Device Server\n"
  70 "\n"
  71 "  -h, --help                display this help and exit\n"
  72 "  -V, --version             output version information and exit\n"
  73 "\n"
  74 "Connection properties:\n"
  75 "  -p, --port=PORT           port to listen on (default `%d')\n"
  76 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  77 "  -k, --socket=PATH         path to the unix socket\n"
  78 "                            (default '"SOCKET_PATH"')\n"
  79 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  80 "  -t, --persistent          don't exit on the last connection\n"
  81 "  -v, --verbose             display extra debugging information\n"
  82 "  -x, --export-name=NAME    expose export by name\n"
  83 "\n"
  84 "Exposing part of the image:\n"
  85 "  -o, --offset=OFFSET       offset into the image\n"
  86 "  -P, --partition=NUM       only expose partition NUM\n"
  87 "\n"
  88 "General purpose options:\n"
  89 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
  90 "                            passwords and/or encryption keys\n"
  91 #ifdef __linux__
  92 "Kernel NBD client support:\n"
  93 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
  94 "  -d, --disconnect          disconnect the specified device\n"
  95 "\n"
  96 #endif
  97 "\n"
  98 "Block device options:\n"
  99 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
 100 "  -r, --read-only           export read-only\n"
 101 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
 102 "                            file with backing_file=FILE, redirect the write to\n"
 103 "                            the temporary one\n"
 104 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 105 "                            load an internal snapshot inside FILE and export it\n"
 106 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
 107 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 108 "                            '[ID_OR_NAME]'\n"
 109 "  -n, --nocache             disable host cache\n"
 110 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
 111 "      --aio=MODE            set AIO mode (native or threads)\n"
 112 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 113 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 114 "      --image-opts          treat FILE as a full set of image options\n"
 115 "\n"
 116 "Report bugs to <qemu-devel@nongnu.org>\n"
 117     , name, NBD_DEFAULT_PORT, "DEVICE");
 118 }
 119
 120 static void version(const char *name)
 121 {
 122     printf(
 123 "%s version 0.0.1\n"
 124 "Written by Anthony Liguori.\n"
 125 "\n"
 126 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
 127 "This is free software; see the source for copying conditions.  There is NO\n"
 128 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 129     , name);
 130 }
 131
 132 struct partition_record
 133 {
 134     uint8_t bootable;
 135     uint8_t start_head;
 136     uint32_t start_cylinder;
 137     uint8_t start_sector;
 138     uint8_t system;
 139     uint8_t end_head;
 140     uint8_t end_cylinder;
 141     uint8_t end_sector;
 142     uint32_t start_sector_abs;
 143     uint32_t nb_sectors_abs;
 144 };
 145
 146 static void read_partition(uint8_t *p, struct partition_record *r)
 147 {
 148     r->bootable = p[0];
 149     r->start_head = p[1];
 150     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 151     r->start_sector = p[2] & 0x3f;
 152     r->system = p[4];
 153     r->end_head = p[5];
 154     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 155     r->end_sector = p[6] & 0x3f;
 156
 157     r->start_sector_abs = le32_to_cpup((uint32_t *)(p +  8));
 158     r->nb_sectors_abs   = le32_to_cpup((uint32_t *)(p + 12));
 159 }
 160
 161 static int find_partition(BlockBackend *blk, int partition,
 162                           off_t *offset, off_t *size)
 163 {
 164     struct partition_record mbr[4];
 165     uint8_t data[MBR_SIZE];
 166     int i;
 167     int ext_partnum = 4;
 168     int ret;
 169
 170     ret = blk_pread(blk, 0, data, sizeof(data));
 171     if (ret < 0) {
 172         error_report("error while reading: %s", strerror(-ret));
 173         exit(EXIT_FAILURE);
 174     }
 175
 176     if (data[510] != 0x55 || data[511] != 0xaa) {
 177         return -EINVAL;
 178     }
 179
 180     for (i = 0; i < 4; i++) {
 181         read_partition(&data[446 + 16 * i], &mbr[i]);
 182
 183         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
 184             continue;
 185         }
 186
 187         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 188             struct partition_record ext[4];
 189             uint8_t data1[MBR_SIZE];
 190             int j;
 191
 192             ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE,
 193                             data1, sizeof(data1));
 194             if (ret < 0) {
 195                 error_report("error while reading: %s", strerror(-ret));
 196                 exit(EXIT_FAILURE);
 197             }
 198
 199             for (j = 0; j < 4; j++) {
 200                 read_partition(&data1[446 + 16 * j], &ext[j]);
 201                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
 202                     continue;
 203                 }
 204
 205                 if ((ext_partnum + j + 1) == partition) {
 206                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 207                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 208                     return 0;
 209                 }
 210             }
 211             ext_partnum += 4;
 212         } else if ((i + 1) == partition) {
 213             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 214             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 215             return 0;
 216         }
 217     }
 218
 219     return -ENOENT;
 220 }
 221
 222 static void termsig_handler(int signum)
 223 {
 224     atomic_cmpxchg(&state, RUNNING, TERMINATE);
 225     qemu_notify_event();
 226 }
 227
 228
 229 static void *show_parts(void *arg)
 230 {
 231     char *device = arg;
 232     int nbd;
 233
 234     /* linux just needs an open() to trigger
 235      * the partition table update
 236      * but remember to load the module with max_part != 0 :
 237      *     modprobe nbd max_part=63
 238      */
 239     nbd = open(device, O_RDWR);
 240     if (nbd >= 0) {
 241         close(nbd);
 242     }
 243     return NULL;
 244 }
 245
 246 static void *nbd_client_thread(void *arg)
 247 {
 248     char *device = arg;
 249     off_t size;
 250     uint32_t nbdflags;
 251     QIOChannelSocket *sioc;
 252     int fd;
 253     int ret;
 254     pthread_t show_parts_thread;
 255     Error *local_error = NULL;
 256
 257     sioc = qio_channel_socket_new();
 258     if (qio_channel_socket_connect_sync(sioc,
 259                                         saddr,
 260                                         &local_error) < 0) {
 261         error_report_err(local_error);
 262         goto out;
 263     }
 264
 265     ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), NULL, &nbdflags,
 266                                 NULL, NULL, NULL,
 267                                 &size, &local_error);
 268     if (ret < 0) {
 269         if (local_error) {
 270             error_report_err(local_error);
 271         }
 272         goto out_socket;
 273     }
 274
 275     fd = open(device, O_RDWR);
 276     if (fd < 0) {
 277         /* Linux-only, we can use %m in printf.  */
 278         error_report("Failed to open %s: %m", device);
 279         goto out_socket;
 280     }
 281
 282     ret = nbd_init(fd, sioc, nbdflags, size);
 283     if (ret < 0) {
 284         goto out_fd;
 285     }
 286
 287     /* update partition table */
 288     pthread_create(&show_parts_thread, NULL, show_parts, device);
 289
 290     if (verbose) {
 291         fprintf(stderr, "NBD device %s is now connected to %s\n",
 292                 device, srcpath);
 293     } else {
 294         /* Close stderr so that the qemu-nbd process exits.  */
 295         dup2(STDOUT_FILENO, STDERR_FILENO);
 296     }
 297
 298     ret = nbd_client(fd);
 299     if (ret) {
 300         goto out_fd;
 301     }
 302     close(fd);
 303     object_unref(OBJECT(sioc));
 304     kill(getpid(), SIGTERM);
 305     return (void *) EXIT_SUCCESS;
 306
 307 out_fd:
 308     close(fd);
 309 out_socket:
 310     object_unref(OBJECT(sioc));
 311 out:
 312     kill(getpid(), SIGTERM);
 313     return (void *) EXIT_FAILURE;
 314 }
 315
 316 static int nbd_can_accept(void)
 317 {
 318     return nb_fds < shared;
 319 }
 320
 321 static void nbd_export_closed(NBDExport *exp)
 322 {
 323     assert(state == TERMINATING);
 324     state = TERMINATED;
 325 }
 326
 327 static void nbd_update_server_watch(void);
 328
 329 static void nbd_client_closed(NBDClient *client)
 330 {
 331     nb_fds--;
 332     if (nb_fds == 0 && !persistent && state == RUNNING) {
 333         state = TERMINATE;
 334     }
 335     nbd_update_server_watch();
 336     nbd_client_put(client);
 337 }
 338
 339 static gboolean nbd_accept(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
 340 {
 341     QIOChannelSocket *cioc;
 342
 343     cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
 344                                      NULL);
 345     if (!cioc) {
 346         return TRUE;
 347     }
 348
 349     if (state >= TERMINATE) {
 350         object_unref(OBJECT(cioc));
 351         return TRUE;
 352     }
 353
 354     nb_fds++;
 355     nbd_update_server_watch();
 356     nbd_client_new(newproto ? NULL : exp, cioc,
 357                    tlscreds, NULL, nbd_client_closed);
 358     object_unref(OBJECT(cioc));
 359
 360     return TRUE;
 361 }
 362
 363 static void nbd_update_server_watch(void)
 364 {
 365     if (nbd_can_accept()) {
 366         if (server_watch == -1) {
 367             server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
 368                                                  G_IO_IN,
 369                                                  nbd_accept,
 370                                                  NULL, NULL);
 371         }
 372     } else {
 373         if (server_watch != -1) {
 374             g_source_remove(server_watch);
 375             server_watch = -1;
 376         }
 377     }
 378 }
 379
 380
 381 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 382                                                const char *bindto,
 383                                                const char *port)
 384 {
 385     SocketAddress *saddr;
 386
 387     saddr = g_new0(SocketAddress, 1);
 388     if (sockpath) {
 389         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
 390         saddr->u.q_unix.data = g_new0(UnixSocketAddress, 1);
 391         saddr->u.q_unix.data->path = g_strdup(sockpath);
 392     } else {
 393         InetSocketAddress *inet;
 394         saddr->type = SOCKET_ADDRESS_KIND_INET;
 395         inet = saddr->u.inet.data = g_new0(InetSocketAddress, 1);
 396         inet->host = g_strdup(bindto);
 397         if (port) {
 398             inet->port = g_strdup(port);
 399         } else  {
 400             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 401         }
 402     }
 403
 404     return saddr;
 405 }
 406
 407
 408 static QemuOptsList file_opts = {
 409     .name = "file",
 410     .implied_opt_name = "file",
 411     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 412     .desc = {
 413         /* no elements => accept any params */
 414         { /* end of list */ }
 415     },
 416 };
 417
 418 static QemuOptsList qemu_object_opts = {
 419     .name = "object",
 420     .implied_opt_name = "qom-type",
 421     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 422     .desc = {
 423         { }
 424     },
 425 };
 426
 427
 428
 429 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 430 {
 431     Object *obj;
 432     QCryptoTLSCreds *creds;
 433
 434     obj = object_resolve_path_component(
 435         object_get_objects_root(), id);
 436     if (!obj) {
 437         error_setg(errp, "No TLS credentials with id '%s'",
 438                    id);
 439         return NULL;
 440     }
 441     creds = (QCryptoTLSCreds *)
 442         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 443     if (!creds) {
 444         error_setg(errp, "Object with id '%s' is not TLS credentials",
 445                    id);
 446         return NULL;
 447     }
 448
 449     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
 450         error_setg(errp,
 451                    "Expecting TLS credentials with a server endpoint");
 452         return NULL;
 453     }
 454     object_ref(obj);
 455     return creds;
 456 }
 457
 458
 459 int main(int argc, char **argv)
 460 {
 461     BlockBackend *blk;
 462     BlockDriverState *bs;
 463     off_t dev_offset = 0;
 464     uint32_t nbdflags = 0;
 465     bool disconnect = false;
 466     const char *bindto = "0.0.0.0";
 467     const char *port = NULL;
 468     char *sockpath = NULL;
 469     char *device = NULL;
 470     off_t fd_size;
 471     QemuOpts *sn_opts = NULL;
 472     const char *sn_id_or_name = NULL;
 473     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:";
 474     struct option lopt[] = {
 475         { "help", no_argument, NULL, 'h' },
 476         { "version", no_argument, NULL, 'V' },
 477         { "bind", required_argument, NULL, 'b' },
 478         { "port", required_argument, NULL, 'p' },
 479         { "socket", required_argument, NULL, 'k' },
 480         { "offset", required_argument, NULL, 'o' },
 481         { "read-only", no_argument, NULL, 'r' },
 482         { "partition", required_argument, NULL, 'P' },
 483         { "connect", required_argument, NULL, 'c' },
 484         { "disconnect", no_argument, NULL, 'd' },
 485         { "snapshot", no_argument, NULL, 's' },
 486         { "load-snapshot", required_argument, NULL, 'l' },
 487         { "nocache", no_argument, NULL, 'n' },
 488         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 489         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 490         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 491         { "detect-zeroes", required_argument, NULL,
 492           QEMU_NBD_OPT_DETECT_ZEROES },
 493         { "shared", required_argument, NULL, 'e' },
 494         { "format", required_argument, NULL, 'f' },
 495         { "persistent", no_argument, NULL, 't' },
 496         { "verbose", no_argument, NULL, 'v' },
 497         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 498         { "export-name", required_argument, NULL, 'x' },
 499         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 500         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 501         { NULL, 0, NULL, 0 }
 502     };
 503     int ch;
 504     int opt_ind = 0;
 505     char *end;
 506     int flags = BDRV_O_RDWR;
 507     int partition = -1;
 508     int ret = 0;
 509     bool seen_cache = false;
 510     bool seen_discard = false;
 511     bool seen_aio = false;
 512     pthread_t client_thread;
 513     const char *fmt = NULL;
 514     Error *local_err = NULL;
 515     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 516     QDict *options = NULL;
 517     const char *export_name = NULL;
 518     const char *tlscredsid = NULL;
 519     bool imageOpts = false;
 520     bool writethrough = true;
 521
 522     /* The client thread uses SIGTERM to interrupt the server.  A signal
 523      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 524      */
 525     struct sigaction sa_sigterm;
 526     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 527     sa_sigterm.sa_handler = termsig_handler;
 528     sigaction(SIGTERM, &sa_sigterm, NULL);
 529
 530     if (qcrypto_init(&local_err) < 0) {
 531         error_reportf_err(local_err, "cannot initialize crypto: ");
 532         exit(1);
 533     }
 534
 535     module_call_init(MODULE_INIT_QOM);
 536     qemu_add_opts(&qemu_object_opts);
 537     qemu_init_exec_dir(argv[0]);
 538
 539     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 540         switch (ch) {
 541         case 's':
 542             flags |= BDRV_O_SNAPSHOT;
 543             break;
 544         case 'n':
 545             optarg = (char *) "none";
 546             /* fallthrough */
 547         case QEMU_NBD_OPT_CACHE:
 548             if (seen_cache) {
 549                 error_report("-n and --cache can only be specified once");
 550                 exit(EXIT_FAILURE);
 551             }
 552             seen_cache = true;
 553             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 554                 error_report("Invalid cache mode `%s'", optarg);
 555                 exit(EXIT_FAILURE);
 556             }
 557             break;
 558         case QEMU_NBD_OPT_AIO:
 559             if (seen_aio) {
 560                 error_report("--aio can only be specified once");
 561                 exit(EXIT_FAILURE);
 562             }
 563             seen_aio = true;
 564             if (!strcmp(optarg, "native")) {
 565                 flags |= BDRV_O_NATIVE_AIO;
 566             } else if (!strcmp(optarg, "threads")) {
 567                 /* this is the default */
 568             } else {
 569                error_report("invalid aio mode `%s'", optarg);
 570                exit(EXIT_FAILURE);
 571             }
 572             break;
 573         case QEMU_NBD_OPT_DISCARD:
 574             if (seen_discard) {
 575                 error_report("--discard can only be specified once");
 576                 exit(EXIT_FAILURE);
 577             }
 578             seen_discard = true;
 579             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 580                 error_report("Invalid discard mode `%s'", optarg);
 581                 exit(EXIT_FAILURE);
 582             }
 583             break;
 584         case QEMU_NBD_OPT_DETECT_ZEROES:
 585             detect_zeroes =
 586                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
 587                                 optarg,
 588                                 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
 589                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 590                                 &local_err);
 591             if (local_err) {
 592                 error_reportf_err(local_err,
 593                                   "Failed to parse detect_zeroes mode: ");
 594                 exit(EXIT_FAILURE);
 595             }
 596             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 597                 !(flags & BDRV_O_UNMAP)) {
 598                 error_report("setting detect-zeroes to unmap is not allowed "
 599                              "without setting discard operation to unmap");
 600                 exit(EXIT_FAILURE);
 601             }
 602             break;
 603         case 'b':
 604             bindto = optarg;
 605             break;
 606         case 'p':
 607             port = optarg;
 608             break;
 609         case 'o':
 610                 dev_offset = strtoll (optarg, &end, 0);
 611             if (*end) {
 612                 error_report("Invalid offset `%s'", optarg);
 613                 exit(EXIT_FAILURE);
 614             }
 615             if (dev_offset < 0) {
 616                 error_report("Offset must be positive `%s'", optarg);
 617                 exit(EXIT_FAILURE);
 618             }
 619             break;
 620         case 'l':
 621             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 622                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 623                                                   optarg, false);
 624                 if (!sn_opts) {
 625                     error_report("Failed in parsing snapshot param `%s'",
 626                                  optarg);
 627                     exit(EXIT_FAILURE);
 628                 }
 629             } else {
 630                 sn_id_or_name = optarg;
 631             }
 632             /* fall through */
 633         case 'r':
 634             nbdflags |= NBD_FLAG_READ_ONLY;
 635             flags &= ~BDRV_O_RDWR;
 636             break;
 637         case 'P':
 638             partition = strtol(optarg, &end, 0);
 639             if (*end) {
 640                 error_report("Invalid partition `%s'", optarg);
 641                 exit(EXIT_FAILURE);
 642             }
 643             if (partition < 1 || partition > 8) {
 644                 error_report("Invalid partition %d", partition);
 645                 exit(EXIT_FAILURE);
 646             }
 647             break;
 648         case 'k':
 649             sockpath = optarg;
 650             if (sockpath[0] != '/') {
 651                 error_report("socket path must be absolute");
 652                 exit(EXIT_FAILURE);
 653             }
 654             break;
 655         case 'd':
 656             disconnect = true;
 657             break;
 658         case 'c':
 659             device = optarg;
 660             break;
 661         case 'e':
 662             shared = strtol(optarg, &end, 0);
 663             if (*end) {
 664                 error_report("Invalid shared device number '%s'", optarg);
 665                 exit(EXIT_FAILURE);
 666             }
 667             if (shared < 1) {
 668                 error_report("Shared device number must be greater than 0");
 669                 exit(EXIT_FAILURE);
 670             }
 671             break;
 672         case 'f':
 673             fmt = optarg;
 674             break;
 675         case 't':
 676             persistent = 1;
 677             break;
 678         case 'x':
 679             export_name = optarg;
 680             break;
 681         case 'v':
 682             verbose = 1;
 683             break;
 684         case 'V':
 685             version(argv[0]);
 686             exit(0);
 687             break;
 688         case 'h':
 689             usage(argv[0]);
 690             exit(0);
 691             break;
 692         case '?':
 693             error_report("Try `%s --help' for more information.", argv[0]);
 694             exit(EXIT_FAILURE);
 695         case QEMU_NBD_OPT_OBJECT: {
 696             QemuOpts *opts;
 697             opts = qemu_opts_parse_noisily(&qemu_object_opts,
 698                                            optarg, true);
 699             if (!opts) {
 700                 exit(EXIT_FAILURE);
 701             }
 702         }   break;
 703         case QEMU_NBD_OPT_TLSCREDS:
 704             tlscredsid = optarg;
 705             break;
 706         case QEMU_NBD_OPT_IMAGE_OPTS:
 707             imageOpts = true;
 708             break;
 709         }
 710     }
 711
 712     if ((argc - optind) != 1) {
 713         error_report("Invalid number of arguments");
 714         error_printf("Try `%s --help' for more information.\n", argv[0]);
 715         exit(EXIT_FAILURE);
 716     }
 717
 718     if (qemu_opts_foreach(&qemu_object_opts,
 719                           user_creatable_add_opts_foreach,
 720                           NULL, NULL)) {
 721         exit(EXIT_FAILURE);
 722     }
 723
 724     if (tlscredsid) {
 725         if (sockpath) {
 726             error_report("TLS is only supported with IPv4/IPv6");
 727             exit(EXIT_FAILURE);
 728         }
 729         if (device) {
 730             error_report("TLS is not supported with a host device");
 731             exit(EXIT_FAILURE);
 732         }
 733         if (!export_name) {
 734             /* Set the default NBD protocol export name, since
 735              * we *must* use new style protocol for TLS */
 736             export_name = "";
 737         }
 738         tlscreds = nbd_get_tls_creds(tlscredsid, &local_err);
 739         if (local_err) {
 740             error_report("Failed to get TLS creds %s",
 741                          error_get_pretty(local_err));
 742             exit(EXIT_FAILURE);
 743         }
 744     }
 745
 746     if (disconnect) {
 747         int nbdfd = open(argv[optind], O_RDWR);
 748         if (nbdfd < 0) {
 749             error_report("Cannot open %s: %s", argv[optind],
 750                          strerror(errno));
 751             exit(EXIT_FAILURE);
 752         }
 753         nbd_disconnect(nbdfd);
 754
 755         close(nbdfd);
 756
 757         printf("%s disconnected\n", argv[optind]);
 758
 759         return 0;
 760     }
 761
 762     if (device && !verbose) {
 763         int stderr_fd[2];
 764         pid_t pid;
 765         int ret;
 766
 767         if (qemu_pipe(stderr_fd) < 0) {
 768             error_report("Error setting up communication pipe: %s",
 769                          strerror(errno));
 770             exit(EXIT_FAILURE);
 771         }
 772
 773         /* Now daemonize, but keep a communication channel open to
 774          * print errors and exit with the proper status code.
 775          */
 776         pid = fork();
 777         if (pid < 0) {
 778             error_report("Failed to fork: %s", strerror(errno));
 779             exit(EXIT_FAILURE);
 780         } else if (pid == 0) {
 781             close(stderr_fd[0]);
 782             ret = qemu_daemon(1, 0);
 783
 784             /* Temporarily redirect stderr to the parent's pipe...  */
 785             dup2(stderr_fd[1], STDERR_FILENO);
 786             if (ret < 0) {
 787                 error_report("Failed to daemonize: %s", strerror(errno));
 788                 exit(EXIT_FAILURE);
 789             }
 790
 791             /* ... close the descriptor we inherited and go on.  */
 792             close(stderr_fd[1]);
 793         } else {
 794             bool errors = false;
 795             char *buf;
 796
 797             /* In the parent.  Print error messages from the child until
 798              * it closes the pipe.
 799              */
 800             close(stderr_fd[1]);
 801             buf = g_malloc(1024);
 802             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 803                 errors = true;
 804                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 805                 if (ret < 0) {
 806                     exit(EXIT_FAILURE);
 807                 }
 808             }
 809             if (ret < 0) {
 810                 error_report("Cannot read from daemon: %s",
 811                              strerror(errno));
 812                 exit(EXIT_FAILURE);
 813             }
 814
 815             /* Usually the daemon should not print any message.
 816              * Exit with zero status in that case.
 817              */
 818             exit(errors);
 819         }
 820     }
 821
 822     if (device != NULL && sockpath == NULL) {
 823         sockpath = g_malloc(128);
 824         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 825     }
 826
 827     saddr = nbd_build_socket_address(sockpath, bindto, port);
 828
 829     if (qemu_init_main_loop(&local_err)) {
 830         error_report_err(local_err);
 831         exit(EXIT_FAILURE);
 832     }
 833     bdrv_init();
 834     atexit(bdrv_close_all);
 835
 836     srcpath = argv[optind];
 837     if (imageOpts) {
 838         QemuOpts *opts;
 839         if (fmt) {
 840             error_report("--image-opts and -f are mutually exclusive");
 841             exit(EXIT_FAILURE);
 842         }
 843         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
 844         if (!opts) {
 845             qemu_opts_reset(&file_opts);
 846             exit(EXIT_FAILURE);
 847         }
 848         options = qemu_opts_to_qdict(opts, NULL);
 849         qemu_opts_reset(&file_opts);
 850         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
 851     } else {
 852         if (fmt) {
 853             options = qdict_new();
 854             qdict_put(options, "driver", qstring_from_str(fmt));
 855         }
 856         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
 857     }
 858
 859     if (!blk) {
 860         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
 861                           argv[optind]);
 862         exit(EXIT_FAILURE);
 863     }
 864     bs = blk_bs(blk);
 865
 866     blk_set_enable_write_cache(blk, !writethrough);
 867
 868     if (sn_opts) {
 869         ret = bdrv_snapshot_load_tmp(bs,
 870                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 871                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 872                                      &local_err);
 873     } else if (sn_id_or_name) {
 874         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 875                                                    &local_err);
 876     }
 877     if (ret < 0) {
 878         error_reportf_err(local_err, "Failed to load snapshot: ");
 879         exit(EXIT_FAILURE);
 880     }
 881
 882     bs->detect_zeroes = detect_zeroes;
 883     fd_size = blk_getlength(blk);
 884     if (fd_size < 0) {
 885         error_report("Failed to determine the image length: %s",
 886                      strerror(-fd_size));
 887         exit(EXIT_FAILURE);
 888     }
 889
 890     if (partition != -1) {
 891         ret = find_partition(blk, partition, &dev_offset, &fd_size);
 892         if (ret < 0) {
 893             error_report("Could not find partition %d: %s", partition,
 894                          strerror(-ret));
 895             exit(EXIT_FAILURE);
 896         }
 897     }
 898
 899     exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
 900                          &local_err);
 901     if (!exp) {
 902         error_report_err(local_err);
 903         exit(EXIT_FAILURE);
 904     }
 905     if (export_name) {
 906         nbd_export_set_name(exp, export_name);
 907         newproto = true;
 908     }
 909
 910     server_ioc = qio_channel_socket_new();
 911     if (qio_channel_socket_listen_sync(server_ioc, saddr, &local_err) < 0) {
 912         object_unref(OBJECT(server_ioc));
 913         error_report_err(local_err);
 914         return 1;
 915     }
 916
 917     if (device) {
 918         int ret;
 919
 920         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 921         if (ret != 0) {
 922             error_report("Failed to create client thread: %s", strerror(ret));
 923             exit(EXIT_FAILURE);
 924         }
 925     } else {
 926         /* Shut up GCC warnings.  */
 927         memset(&client_thread, 0, sizeof(client_thread));
 928     }
 929
 930     nbd_update_server_watch();
 931
 932     /* now when the initialization is (almost) complete, chdir("/")
 933      * to free any busy filesystems */
 934     if (chdir("/") < 0) {
 935         error_report("Could not chdir to root directory: %s",
 936                      strerror(errno));
 937         exit(EXIT_FAILURE);
 938     }
 939
 940     state = RUNNING;
 941     do {
 942         main_loop_wait(false);
 943         if (state == TERMINATE) {
 944             state = TERMINATING;
 945             nbd_export_close(exp);
 946             nbd_export_put(exp);
 947             exp = NULL;
 948         }
 949     } while (state != TERMINATED);
 950
 951     blk_unref(blk);
 952     if (sockpath) {
 953         unlink(sockpath);
 954     }
 955
 956     qemu_opts_del(sn_opts);
 957
 958     if (device) {
 959         void *ret;
 960         pthread_join(client_thread, &ret);
 961         exit(ret != NULL);
 962     } else {
 963         exit(EXIT_SUCCESS);
 964     }
 965 }