qemu-nbd.c

   1 /*
   2  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
   3  *
   4  *  Network Block Device
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; under version 2 of the License.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "qemu/osdep.h"
  20 #include "qapi/error.h"
  21 #include "qemu-common.h"
  22 #include "qemu/cutils.h"
  23 #include "sysemu/block-backend.h"
  24 #include "block/block_int.h"
  25 #include "block/nbd.h"
  26 #include "qemu/main-loop.h"
  27 #include "qemu/error-report.h"
  28 #include "qemu/config-file.h"
  29 #include "block/snapshot.h"
  30 #include "qapi/util.h"
  31 #include "qapi/qmp/qstring.h"
  32 #include "qom/object_interfaces.h"
  33 #include "io/channel-socket.h"
  34 #include "crypto/init.h"
  35
  36 #include <getopt.h>
  37 #include <libgen.h>
  38 #include <pthread.h>
  39
  40 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  41 #define QEMU_NBD_OPT_CACHE         256
  42 #define QEMU_NBD_OPT_AIO           257
  43 #define QEMU_NBD_OPT_DISCARD       258
  44 #define QEMU_NBD_OPT_DETECT_ZEROES 259
  45 #define QEMU_NBD_OPT_OBJECT        260
  46 #define QEMU_NBD_OPT_TLSCREDS      261
  47 #define QEMU_NBD_OPT_IMAGE_OPTS    262
  48
  49 static NBDExport *exp;
  50 static bool newproto;
  51 static int verbose;
  52 static char *srcpath;
  53 static SocketAddress *saddr;
  54 static int persistent = 0;
  55 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  56 static int shared = 1;
  57 static int nb_fds;
  58 static QIOChannelSocket *server_ioc;
  59 static int server_watch = -1;
  60 static QCryptoTLSCreds *tlscreds;
  61
  62 static void usage(const char *name)
  63 {
  64     (printf) (
  65 "Usage: %s [OPTIONS] FILE\n"
  66 "QEMU Disk Network Block Device Server\n"
  67 "\n"
  68 "  -h, --help                display this help and exit\n"
  69 "  -V, --version             output version information and exit\n"
  70 "\n"
  71 "Connection properties:\n"
  72 "  -p, --port=PORT           port to listen on (default `%d')\n"
  73 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  74 "  -k, --socket=PATH         path to the unix socket\n"
  75 "                            (default '"SOCKET_PATH"')\n"
  76 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  77 "  -t, --persistent          don't exit on the last connection\n"
  78 "  -v, --verbose             display extra debugging information\n"
  79 "  -x, --export-name=NAME    expose export by name\n"
  80 "\n"
  81 "Exposing part of the image:\n"
  82 "  -o, --offset=OFFSET       offset into the image\n"
  83 "  -P, --partition=NUM       only expose partition NUM\n"
  84 "\n"
  85 "General purpose options:\n"
  86 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
  87 "                            passwords and/or encryption keys\n"
  88 #ifdef __linux__
  89 "Kernel NBD client support:\n"
  90 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
  91 "  -d, --disconnect          disconnect the specified device\n"
  92 "\n"
  93 #endif
  94 "\n"
  95 "Block device options:\n"
  96 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
  97 "  -r, --read-only           export read-only\n"
  98 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
  99 "                            file with backing_file=FILE, redirect the write to\n"
 100 "                            the temporary one\n"
 101 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 102 "                            load an internal snapshot inside FILE and export it\n"
 103 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
 104 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 105 "                            '[ID_OR_NAME]'\n"
 106 "  -n, --nocache             disable host cache\n"
 107 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
 108 "      --aio=MODE            set AIO mode (native or threads)\n"
 109 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 110 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 111 "      --image-opts          treat FILE as a full set of image options\n"
 112 "\n"
 113 "Report bugs to <qemu-devel@nongnu.org>\n"
 114     , name, NBD_DEFAULT_PORT, "DEVICE");
 115 }
 116
 117 static void version(const char *name)
 118 {
 119     printf(
 120 "%s version 0.0.1\n"
 121 "Written by Anthony Liguori.\n"
 122 "\n"
 123 "Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
 124 "This is free software; see the source for copying conditions.  There is NO\n"
 125 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 126     , name);
 127 }
 128
 129 struct partition_record
 130 {
 131     uint8_t bootable;
 132     uint8_t start_head;
 133     uint32_t start_cylinder;
 134     uint8_t start_sector;
 135     uint8_t system;
 136     uint8_t end_head;
 137     uint8_t end_cylinder;
 138     uint8_t end_sector;
 139     uint32_t start_sector_abs;
 140     uint32_t nb_sectors_abs;
 141 };
 142
 143 static void read_partition(uint8_t *p, struct partition_record *r)
 144 {
 145     r->bootable = p[0];
 146     r->start_head = p[1];
 147     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 148     r->start_sector = p[2] & 0x3f;
 149     r->system = p[4];
 150     r->end_head = p[5];
 151     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 152     r->end_sector = p[6] & 0x3f;
 153
 154     r->start_sector_abs = le32_to_cpup((uint32_t *)(p +  8));
 155     r->nb_sectors_abs   = le32_to_cpup((uint32_t *)(p + 12));
 156 }
 157
 158 static int find_partition(BlockBackend *blk, int partition,
 159                           off_t *offset, off_t *size)
 160 {
 161     struct partition_record mbr[4];
 162     uint8_t data[512];
 163     int i;
 164     int ext_partnum = 4;
 165     int ret;
 166
 167     if ((ret = blk_read(blk, 0, data, 1)) < 0) {
 168         error_report("error while reading: %s", strerror(-ret));
 169         exit(EXIT_FAILURE);
 170     }
 171
 172     if (data[510] != 0x55 || data[511] != 0xaa) {
 173         return -EINVAL;
 174     }
 175
 176     for (i = 0; i < 4; i++) {
 177         read_partition(&data[446 + 16 * i], &mbr[i]);
 178
 179         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
 180             continue;
 181         }
 182
 183         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 184             struct partition_record ext[4];
 185             uint8_t data1[512];
 186             int j;
 187
 188             if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 0) {
 189                 error_report("error while reading: %s", strerror(-ret));
 190                 exit(EXIT_FAILURE);
 191             }
 192
 193             for (j = 0; j < 4; j++) {
 194                 read_partition(&data1[446 + 16 * j], &ext[j]);
 195                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
 196                     continue;
 197                 }
 198
 199                 if ((ext_partnum + j + 1) == partition) {
 200                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 201                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 202                     return 0;
 203                 }
 204             }
 205             ext_partnum += 4;
 206         } else if ((i + 1) == partition) {
 207             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 208             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 209             return 0;
 210         }
 211     }
 212
 213     return -ENOENT;
 214 }
 215
 216 static void termsig_handler(int signum)
 217 {
 218     atomic_cmpxchg(&state, RUNNING, TERMINATE);
 219     qemu_notify_event();
 220 }
 221
 222
 223 static void *show_parts(void *arg)
 224 {
 225     char *device = arg;
 226     int nbd;
 227
 228     /* linux just needs an open() to trigger
 229      * the partition table update
 230      * but remember to load the module with max_part != 0 :
 231      *     modprobe nbd max_part=63
 232      */
 233     nbd = open(device, O_RDWR);
 234     if (nbd >= 0) {
 235         close(nbd);
 236     }
 237     return NULL;
 238 }
 239
 240 static void *nbd_client_thread(void *arg)
 241 {
 242     char *device = arg;
 243     off_t size;
 244     uint32_t nbdflags;
 245     QIOChannelSocket *sioc;
 246     int fd;
 247     int ret;
 248     pthread_t show_parts_thread;
 249     Error *local_error = NULL;
 250
 251     sioc = qio_channel_socket_new();
 252     if (qio_channel_socket_connect_sync(sioc,
 253                                         saddr,
 254                                         &local_error) < 0) {
 255         error_report_err(local_error);
 256         goto out;
 257     }
 258
 259     ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), NULL, &nbdflags,
 260                                 NULL, NULL, NULL,
 261                                 &size, &local_error);
 262     if (ret < 0) {
 263         if (local_error) {
 264             error_report_err(local_error);
 265         }
 266         goto out_socket;
 267     }
 268
 269     fd = open(device, O_RDWR);
 270     if (fd < 0) {
 271         /* Linux-only, we can use %m in printf.  */
 272         error_report("Failed to open %s: %m", device);
 273         goto out_socket;
 274     }
 275
 276     ret = nbd_init(fd, sioc, nbdflags, size);
 277     if (ret < 0) {
 278         goto out_fd;
 279     }
 280
 281     /* update partition table */
 282     pthread_create(&show_parts_thread, NULL, show_parts, device);
 283
 284     if (verbose) {
 285         fprintf(stderr, "NBD device %s is now connected to %s\n",
 286                 device, srcpath);
 287     } else {
 288         /* Close stderr so that the qemu-nbd process exits.  */
 289         dup2(STDOUT_FILENO, STDERR_FILENO);
 290     }
 291
 292     ret = nbd_client(fd);
 293     if (ret) {
 294         goto out_fd;
 295     }
 296     close(fd);
 297     object_unref(OBJECT(sioc));
 298     kill(getpid(), SIGTERM);
 299     return (void *) EXIT_SUCCESS;
 300
 301 out_fd:
 302     close(fd);
 303 out_socket:
 304     object_unref(OBJECT(sioc));
 305 out:
 306     kill(getpid(), SIGTERM);
 307     return (void *) EXIT_FAILURE;
 308 }
 309
 310 static int nbd_can_accept(void)
 311 {
 312     return nb_fds < shared;
 313 }
 314
 315 static void nbd_export_closed(NBDExport *exp)
 316 {
 317     assert(state == TERMINATING);
 318     state = TERMINATED;
 319 }
 320
 321 static void nbd_update_server_watch(void);
 322
 323 static void nbd_client_closed(NBDClient *client)
 324 {
 325     nb_fds--;
 326     if (nb_fds == 0 && !persistent && state == RUNNING) {
 327         state = TERMINATE;
 328     }
 329     nbd_update_server_watch();
 330     nbd_client_put(client);
 331 }
 332
 333 static gboolean nbd_accept(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
 334 {
 335     QIOChannelSocket *cioc;
 336
 337     cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
 338                                      NULL);
 339     if (!cioc) {
 340         return TRUE;
 341     }
 342
 343     if (state >= TERMINATE) {
 344         object_unref(OBJECT(cioc));
 345         return TRUE;
 346     }
 347
 348     nb_fds++;
 349     nbd_update_server_watch();
 350     nbd_client_new(newproto ? NULL : exp, cioc,
 351                    tlscreds, NULL, nbd_client_closed);
 352     object_unref(OBJECT(cioc));
 353
 354     return TRUE;
 355 }
 356
 357 static void nbd_update_server_watch(void)
 358 {
 359     if (nbd_can_accept()) {
 360         if (server_watch == -1) {
 361             server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
 362                                                  G_IO_IN,
 363                                                  nbd_accept,
 364                                                  NULL, NULL);
 365         }
 366     } else {
 367         if (server_watch != -1) {
 368             g_source_remove(server_watch);
 369             server_watch = -1;
 370         }
 371     }
 372 }
 373
 374
 375 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 376                                                const char *bindto,
 377                                                const char *port)
 378 {
 379     SocketAddress *saddr;
 380
 381     saddr = g_new0(SocketAddress, 1);
 382     if (sockpath) {
 383         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
 384         saddr->u.q_unix.data = g_new0(UnixSocketAddress, 1);
 385         saddr->u.q_unix.data->path = g_strdup(sockpath);
 386     } else {
 387         InetSocketAddress *inet;
 388         saddr->type = SOCKET_ADDRESS_KIND_INET;
 389         inet = saddr->u.inet.data = g_new0(InetSocketAddress, 1);
 390         inet->host = g_strdup(bindto);
 391         if (port) {
 392             inet->port = g_strdup(port);
 393         } else  {
 394             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 395         }
 396     }
 397
 398     return saddr;
 399 }
 400
 401
 402 static QemuOptsList file_opts = {
 403     .name = "file",
 404     .implied_opt_name = "file",
 405     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 406     .desc = {
 407         /* no elements => accept any params */
 408         { /* end of list */ }
 409     },
 410 };
 411
 412 static QemuOptsList qemu_object_opts = {
 413     .name = "object",
 414     .implied_opt_name = "qom-type",
 415     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 416     .desc = {
 417         { }
 418     },
 419 };
 420
 421
 422
 423 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 424 {
 425     Object *obj;
 426     QCryptoTLSCreds *creds;
 427
 428     obj = object_resolve_path_component(
 429         object_get_objects_root(), id);
 430     if (!obj) {
 431         error_setg(errp, "No TLS credentials with id '%s'",
 432                    id);
 433         return NULL;
 434     }
 435     creds = (QCryptoTLSCreds *)
 436         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 437     if (!creds) {
 438         error_setg(errp, "Object with id '%s' is not TLS credentials",
 439                    id);
 440         return NULL;
 441     }
 442
 443     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
 444         error_setg(errp,
 445                    "Expecting TLS credentials with a server endpoint");
 446         return NULL;
 447     }
 448     object_ref(obj);
 449     return creds;
 450 }
 451
 452
 453 int main(int argc, char **argv)
 454 {
 455     BlockBackend *blk;
 456     BlockDriverState *bs;
 457     off_t dev_offset = 0;
 458     uint32_t nbdflags = 0;
 459     bool disconnect = false;
 460     const char *bindto = "0.0.0.0";
 461     const char *port = NULL;
 462     char *sockpath = NULL;
 463     char *device = NULL;
 464     off_t fd_size;
 465     QemuOpts *sn_opts = NULL;
 466     const char *sn_id_or_name = NULL;
 467     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:";
 468     struct option lopt[] = {
 469         { "help", no_argument, NULL, 'h' },
 470         { "version", no_argument, NULL, 'V' },
 471         { "bind", required_argument, NULL, 'b' },
 472         { "port", required_argument, NULL, 'p' },
 473         { "socket", required_argument, NULL, 'k' },
 474         { "offset", required_argument, NULL, 'o' },
 475         { "read-only", no_argument, NULL, 'r' },
 476         { "partition", required_argument, NULL, 'P' },
 477         { "connect", required_argument, NULL, 'c' },
 478         { "disconnect", no_argument, NULL, 'd' },
 479         { "snapshot", no_argument, NULL, 's' },
 480         { "load-snapshot", required_argument, NULL, 'l' },
 481         { "nocache", no_argument, NULL, 'n' },
 482         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 483         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 484         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 485         { "detect-zeroes", required_argument, NULL,
 486           QEMU_NBD_OPT_DETECT_ZEROES },
 487         { "shared", required_argument, NULL, 'e' },
 488         { "format", required_argument, NULL, 'f' },
 489         { "persistent", no_argument, NULL, 't' },
 490         { "verbose", no_argument, NULL, 'v' },
 491         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 492         { "export-name", required_argument, NULL, 'x' },
 493         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 494         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 495         { NULL, 0, NULL, 0 }
 496     };
 497     int ch;
 498     int opt_ind = 0;
 499     char *end;
 500     int flags = BDRV_O_RDWR;
 501     int partition = -1;
 502     int ret = 0;
 503     bool seen_cache = false;
 504     bool seen_discard = false;
 505     bool seen_aio = false;
 506     pthread_t client_thread;
 507     const char *fmt = NULL;
 508     Error *local_err = NULL;
 509     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 510     QDict *options = NULL;
 511     const char *export_name = NULL;
 512     const char *tlscredsid = NULL;
 513     bool imageOpts = false;
 514     bool writethrough = true;
 515
 516     /* The client thread uses SIGTERM to interrupt the server.  A signal
 517      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 518      */
 519     struct sigaction sa_sigterm;
 520     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 521     sa_sigterm.sa_handler = termsig_handler;
 522     sigaction(SIGTERM, &sa_sigterm, NULL);
 523
 524     if (qcrypto_init(&local_err) < 0) {
 525         error_reportf_err(local_err, "cannot initialize crypto: ");
 526         exit(1);
 527     }
 528
 529     module_call_init(MODULE_INIT_QOM);
 530     qemu_add_opts(&qemu_object_opts);
 531     qemu_init_exec_dir(argv[0]);
 532
 533     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 534         switch (ch) {
 535         case 's':
 536             flags |= BDRV_O_SNAPSHOT;
 537             break;
 538         case 'n':
 539             optarg = (char *) "none";
 540             /* fallthrough */
 541         case QEMU_NBD_OPT_CACHE:
 542             if (seen_cache) {
 543                 error_report("-n and --cache can only be specified once");
 544                 exit(EXIT_FAILURE);
 545             }
 546             seen_cache = true;
 547             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 548                 error_report("Invalid cache mode `%s'", optarg);
 549                 exit(EXIT_FAILURE);
 550             }
 551             break;
 552         case QEMU_NBD_OPT_AIO:
 553             if (seen_aio) {
 554                 error_report("--aio can only be specified once");
 555                 exit(EXIT_FAILURE);
 556             }
 557             seen_aio = true;
 558             if (!strcmp(optarg, "native")) {
 559                 flags |= BDRV_O_NATIVE_AIO;
 560             } else if (!strcmp(optarg, "threads")) {
 561                 /* this is the default */
 562             } else {
 563                error_report("invalid aio mode `%s'", optarg);
 564                exit(EXIT_FAILURE);
 565             }
 566             break;
 567         case QEMU_NBD_OPT_DISCARD:
 568             if (seen_discard) {
 569                 error_report("--discard can only be specified once");
 570                 exit(EXIT_FAILURE);
 571             }
 572             seen_discard = true;
 573             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 574                 error_report("Invalid discard mode `%s'", optarg);
 575                 exit(EXIT_FAILURE);
 576             }
 577             break;
 578         case QEMU_NBD_OPT_DETECT_ZEROES:
 579             detect_zeroes =
 580                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
 581                                 optarg,
 582                                 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
 583                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 584                                 &local_err);
 585             if (local_err) {
 586                 error_reportf_err(local_err,
 587                                   "Failed to parse detect_zeroes mode: ");
 588                 exit(EXIT_FAILURE);
 589             }
 590             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 591                 !(flags & BDRV_O_UNMAP)) {
 592                 error_report("setting detect-zeroes to unmap is not allowed "
 593                              "without setting discard operation to unmap");
 594                 exit(EXIT_FAILURE);
 595             }
 596             break;
 597         case 'b':
 598             bindto = optarg;
 599             break;
 600         case 'p':
 601             port = optarg;
 602             break;
 603         case 'o':
 604                 dev_offset = strtoll (optarg, &end, 0);
 605             if (*end) {
 606                 error_report("Invalid offset `%s'", optarg);
 607                 exit(EXIT_FAILURE);
 608             }
 609             if (dev_offset < 0) {
 610                 error_report("Offset must be positive `%s'", optarg);
 611                 exit(EXIT_FAILURE);
 612             }
 613             break;
 614         case 'l':
 615             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 616                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 617                                                   optarg, false);
 618                 if (!sn_opts) {
 619                     error_report("Failed in parsing snapshot param `%s'",
 620                                  optarg);
 621                     exit(EXIT_FAILURE);
 622                 }
 623             } else {
 624                 sn_id_or_name = optarg;
 625             }
 626             /* fall through */
 627         case 'r':
 628             nbdflags |= NBD_FLAG_READ_ONLY;
 629             flags &= ~BDRV_O_RDWR;
 630             break;
 631         case 'P':
 632             partition = strtol(optarg, &end, 0);
 633             if (*end) {
 634                 error_report("Invalid partition `%s'", optarg);
 635                 exit(EXIT_FAILURE);
 636             }
 637             if (partition < 1 || partition > 8) {
 638                 error_report("Invalid partition %d", partition);
 639                 exit(EXIT_FAILURE);
 640             }
 641             break;
 642         case 'k':
 643             sockpath = optarg;
 644             if (sockpath[0] != '/') {
 645                 error_report("socket path must be absolute");
 646                 exit(EXIT_FAILURE);
 647             }
 648             break;
 649         case 'd':
 650             disconnect = true;
 651             break;
 652         case 'c':
 653             device = optarg;
 654             break;
 655         case 'e':
 656             shared = strtol(optarg, &end, 0);
 657             if (*end) {
 658                 error_report("Invalid shared device number '%s'", optarg);
 659                 exit(EXIT_FAILURE);
 660             }
 661             if (shared < 1) {
 662                 error_report("Shared device number must be greater than 0");
 663                 exit(EXIT_FAILURE);
 664             }
 665             break;
 666         case 'f':
 667             fmt = optarg;
 668             break;
 669         case 't':
 670             persistent = 1;
 671             break;
 672         case 'x':
 673             export_name = optarg;
 674             break;
 675         case 'v':
 676             verbose = 1;
 677             break;
 678         case 'V':
 679             version(argv[0]);
 680             exit(0);
 681             break;
 682         case 'h':
 683             usage(argv[0]);
 684             exit(0);
 685             break;
 686         case '?':
 687             error_report("Try `%s --help' for more information.", argv[0]);
 688             exit(EXIT_FAILURE);
 689         case QEMU_NBD_OPT_OBJECT: {
 690             QemuOpts *opts;
 691             opts = qemu_opts_parse_noisily(&qemu_object_opts,
 692                                            optarg, true);
 693             if (!opts) {
 694                 exit(EXIT_FAILURE);
 695             }
 696         }   break;
 697         case QEMU_NBD_OPT_TLSCREDS:
 698             tlscredsid = optarg;
 699             break;
 700         case QEMU_NBD_OPT_IMAGE_OPTS:
 701             imageOpts = true;
 702             break;
 703         }
 704     }
 705
 706     if ((argc - optind) != 1) {
 707         error_report("Invalid number of arguments");
 708         error_printf("Try `%s --help' for more information.\n", argv[0]);
 709         exit(EXIT_FAILURE);
 710     }
 711
 712     if (qemu_opts_foreach(&qemu_object_opts,
 713                           user_creatable_add_opts_foreach,
 714                           NULL, &local_err)) {
 715         error_report_err(local_err);
 716         exit(EXIT_FAILURE);
 717     }
 718
 719     if (tlscredsid) {
 720         if (sockpath) {
 721             error_report("TLS is only supported with IPv4/IPv6");
 722             exit(EXIT_FAILURE);
 723         }
 724         if (device) {
 725             error_report("TLS is not supported with a host device");
 726             exit(EXIT_FAILURE);
 727         }
 728         if (!export_name) {
 729             /* Set the default NBD protocol export name, since
 730              * we *must* use new style protocol for TLS */
 731             export_name = "";
 732         }
 733         tlscreds = nbd_get_tls_creds(tlscredsid, &local_err);
 734         if (local_err) {
 735             error_report("Failed to get TLS creds %s",
 736                          error_get_pretty(local_err));
 737             exit(EXIT_FAILURE);
 738         }
 739     }
 740
 741     if (disconnect) {
 742         int nbdfd = open(argv[optind], O_RDWR);
 743         if (nbdfd < 0) {
 744             error_report("Cannot open %s: %s", argv[optind],
 745                          strerror(errno));
 746             exit(EXIT_FAILURE);
 747         }
 748         nbd_disconnect(nbdfd);
 749
 750         close(nbdfd);
 751
 752         printf("%s disconnected\n", argv[optind]);
 753
 754         return 0;
 755     }
 756
 757     if (device && !verbose) {
 758         int stderr_fd[2];
 759         pid_t pid;
 760         int ret;
 761
 762         if (qemu_pipe(stderr_fd) < 0) {
 763             error_report("Error setting up communication pipe: %s",
 764                          strerror(errno));
 765             exit(EXIT_FAILURE);
 766         }
 767
 768         /* Now daemonize, but keep a communication channel open to
 769          * print errors and exit with the proper status code.
 770          */
 771         pid = fork();
 772         if (pid < 0) {
 773             error_report("Failed to fork: %s", strerror(errno));
 774             exit(EXIT_FAILURE);
 775         } else if (pid == 0) {
 776             close(stderr_fd[0]);
 777             ret = qemu_daemon(1, 0);
 778
 779             /* Temporarily redirect stderr to the parent's pipe...  */
 780             dup2(stderr_fd[1], STDERR_FILENO);
 781             if (ret < 0) {
 782                 error_report("Failed to daemonize: %s", strerror(errno));
 783                 exit(EXIT_FAILURE);
 784             }
 785
 786             /* ... close the descriptor we inherited and go on.  */
 787             close(stderr_fd[1]);
 788         } else {
 789             bool errors = false;
 790             char *buf;
 791
 792             /* In the parent.  Print error messages from the child until
 793              * it closes the pipe.
 794              */
 795             close(stderr_fd[1]);
 796             buf = g_malloc(1024);
 797             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 798                 errors = true;
 799                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 800                 if (ret < 0) {
 801                     exit(EXIT_FAILURE);
 802                 }
 803             }
 804             if (ret < 0) {
 805                 error_report("Cannot read from daemon: %s",
 806                              strerror(errno));
 807                 exit(EXIT_FAILURE);
 808             }
 809
 810             /* Usually the daemon should not print any message.
 811              * Exit with zero status in that case.
 812              */
 813             exit(errors);
 814         }
 815     }
 816
 817     if (device != NULL && sockpath == NULL) {
 818         sockpath = g_malloc(128);
 819         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 820     }
 821
 822     saddr = nbd_build_socket_address(sockpath, bindto, port);
 823
 824     if (qemu_init_main_loop(&local_err)) {
 825         error_report_err(local_err);
 826         exit(EXIT_FAILURE);
 827     }
 828     bdrv_init();
 829     atexit(bdrv_close_all);
 830
 831     srcpath = argv[optind];
 832     if (imageOpts) {
 833         QemuOpts *opts;
 834         if (fmt) {
 835             error_report("--image-opts and -f are mutually exclusive");
 836             exit(EXIT_FAILURE);
 837         }
 838         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
 839         if (!opts) {
 840             qemu_opts_reset(&file_opts);
 841             exit(EXIT_FAILURE);
 842         }
 843         options = qemu_opts_to_qdict(opts, NULL);
 844         qemu_opts_reset(&file_opts);
 845         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
 846     } else {
 847         if (fmt) {
 848             options = qdict_new();
 849             qdict_put(options, "driver", qstring_from_str(fmt));
 850         }
 851         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
 852     }
 853
 854     if (!blk) {
 855         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
 856                           argv[optind]);
 857         exit(EXIT_FAILURE);
 858     }
 859     bs = blk_bs(blk);
 860
 861     blk_set_enable_write_cache(blk, !writethrough);
 862
 863     if (sn_opts) {
 864         ret = bdrv_snapshot_load_tmp(bs,
 865                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 866                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 867                                      &local_err);
 868     } else if (sn_id_or_name) {
 869         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 870                                                    &local_err);
 871     }
 872     if (ret < 0) {
 873         error_reportf_err(local_err, "Failed to load snapshot: ");
 874         exit(EXIT_FAILURE);
 875     }
 876
 877     bs->detect_zeroes = detect_zeroes;
 878     fd_size = blk_getlength(blk);
 879     if (fd_size < 0) {
 880         error_report("Failed to determine the image length: %s",
 881                      strerror(-fd_size));
 882         exit(EXIT_FAILURE);
 883     }
 884
 885     if (partition != -1) {
 886         ret = find_partition(blk, partition, &dev_offset, &fd_size);
 887         if (ret < 0) {
 888             error_report("Could not find partition %d: %s", partition,
 889                          strerror(-ret));
 890             exit(EXIT_FAILURE);
 891         }
 892     }
 893
 894     exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
 895                          &local_err);
 896     if (!exp) {
 897         error_report_err(local_err);
 898         exit(EXIT_FAILURE);
 899     }
 900     if (export_name) {
 901         nbd_export_set_name(exp, export_name);
 902         newproto = true;
 903     }
 904
 905     server_ioc = qio_channel_socket_new();
 906     if (qio_channel_socket_listen_sync(server_ioc, saddr, &local_err) < 0) {
 907         object_unref(OBJECT(server_ioc));
 908         error_report_err(local_err);
 909         return 1;
 910     }
 911
 912     if (device) {
 913         int ret;
 914
 915         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 916         if (ret != 0) {
 917             error_report("Failed to create client thread: %s", strerror(ret));
 918             exit(EXIT_FAILURE);
 919         }
 920     } else {
 921         /* Shut up GCC warnings.  */
 922         memset(&client_thread, 0, sizeof(client_thread));
 923     }
 924
 925     nbd_update_server_watch();
 926
 927     /* now when the initialization is (almost) complete, chdir("/")
 928      * to free any busy filesystems */
 929     if (chdir("/") < 0) {
 930         error_report("Could not chdir to root directory: %s",
 931                      strerror(errno));
 932         exit(EXIT_FAILURE);
 933     }
 934
 935     state = RUNNING;
 936     do {
 937         main_loop_wait(false);
 938         if (state == TERMINATE) {
 939             state = TERMINATING;
 940             nbd_export_close(exp);
 941             nbd_export_put(exp);
 942             exp = NULL;
 943         }
 944     } while (state != TERMINATED);
 945
 946     blk_unref(blk);
 947     if (sockpath) {
 948         unlink(sockpath);
 949     }
 950
 951     qemu_opts_del(sn_opts);
 952
 953     if (device) {
 954         void *ret;
 955         pthread_join(client_thread, &ret);
 956         exit(ret != NULL);
 957     } else {
 958         exit(EXIT_SUCCESS);
 959     }
 960 }