qemu-nbd.c

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