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                                 &size, &local_error);
 255     if (ret < 0) {
 256         if (local_error) {
 257             error_report_err(local_error);
 258         }
 259         goto out_socket;
 260     }
 261
 262     fd = open(device, O_RDWR);
 263     if (fd < 0) {
 264         /* Linux-only, we can use %m in printf.  */
 265         error_report("Failed to open %s: %m", device);
 266         goto out_socket;
 267     }
 268
 269     ret = nbd_init(fd, sioc, nbdflags, size);
 270     if (ret < 0) {
 271         goto out_fd;
 272     }
 273
 274     /* update partition table */
 275     pthread_create(&show_parts_thread, NULL, show_parts, device);
 276
 277     if (verbose) {
 278         fprintf(stderr, "NBD device %s is now connected to %s\n",
 279                 device, srcpath);
 280     } else {
 281         /* Close stderr so that the qemu-nbd process exits.  */
 282         dup2(STDOUT_FILENO, STDERR_FILENO);
 283     }
 284
 285     ret = nbd_client(fd);
 286     if (ret) {
 287         goto out_fd;
 288     }
 289     close(fd);
 290     object_unref(OBJECT(sioc));
 291     kill(getpid(), SIGTERM);
 292     return (void *) EXIT_SUCCESS;
 293
 294 out_fd:
 295     close(fd);
 296 out_socket:
 297     object_unref(OBJECT(sioc));
 298 out:
 299     kill(getpid(), SIGTERM);
 300     return (void *) EXIT_FAILURE;
 301 }
 302
 303 static int nbd_can_accept(void)
 304 {
 305     return nb_fds < shared;
 306 }
 307
 308 static void nbd_export_closed(NBDExport *exp)
 309 {
 310     assert(state == TERMINATING);
 311     state = TERMINATED;
 312 }
 313
 314 static void nbd_update_server_watch(void);
 315
 316 static void nbd_client_closed(NBDClient *client)
 317 {
 318     nb_fds--;
 319     if (nb_fds == 0 && !persistent && state == RUNNING) {
 320         state = TERMINATE;
 321     }
 322     nbd_update_server_watch();
 323     nbd_client_put(client);
 324 }
 325
 326 static gboolean nbd_accept(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
 327 {
 328     QIOChannelSocket *cioc;
 329
 330     cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
 331                                      NULL);
 332     if (!cioc) {
 333         return TRUE;
 334     }
 335
 336     if (state >= TERMINATE) {
 337         object_unref(OBJECT(cioc));
 338         return TRUE;
 339     }
 340
 341     nb_fds++;
 342     nbd_update_server_watch();
 343     nbd_client_new(newproto ? NULL : exp, cioc, nbd_client_closed);
 344     object_unref(OBJECT(cioc));
 345
 346     return TRUE;
 347 }
 348
 349 static void nbd_update_server_watch(void)
 350 {
 351     if (nbd_can_accept()) {
 352         if (server_watch == -1) {
 353             server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
 354                                                  G_IO_IN,
 355                                                  nbd_accept,
 356                                                  NULL, NULL);
 357         }
 358     } else {
 359         if (server_watch != -1) {
 360             g_source_remove(server_watch);
 361             server_watch = -1;
 362         }
 363     }
 364 }
 365
 366
 367 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 368                                                const char *bindto,
 369                                                const char *port)
 370 {
 371     SocketAddress *saddr;
 372
 373     saddr = g_new0(SocketAddress, 1);
 374     if (sockpath) {
 375         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
 376         saddr->u.q_unix = g_new0(UnixSocketAddress, 1);
 377         saddr->u.q_unix->path = g_strdup(sockpath);
 378     } else {
 379         saddr->type = SOCKET_ADDRESS_KIND_INET;
 380         saddr->u.inet = g_new0(InetSocketAddress, 1);
 381         saddr->u.inet->host = g_strdup(bindto);
 382         if (port) {
 383             saddr->u.inet->port = g_strdup(port);
 384         } else  {
 385             saddr->u.inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 386         }
 387     }
 388
 389     return saddr;
 390 }
 391
 392
 393 static QemuOptsList qemu_object_opts = {
 394     .name = "object",
 395     .implied_opt_name = "qom-type",
 396     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 397     .desc = {
 398         { }
 399     },
 400 };
 401
 402
 403 int main(int argc, char **argv)
 404 {
 405     BlockBackend *blk;
 406     BlockDriverState *bs;
 407     off_t dev_offset = 0;
 408     uint32_t nbdflags = 0;
 409     bool disconnect = false;
 410     const char *bindto = "0.0.0.0";
 411     const char *port = NULL;
 412     char *sockpath = NULL;
 413     char *device = NULL;
 414     off_t fd_size;
 415     QemuOpts *sn_opts = NULL;
 416     const char *sn_id_or_name = NULL;
 417     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:";
 418     struct option lopt[] = {
 419         { "help", 0, NULL, 'h' },
 420         { "version", 0, NULL, 'V' },
 421         { "bind", 1, NULL, 'b' },
 422         { "port", 1, NULL, 'p' },
 423         { "socket", 1, NULL, 'k' },
 424         { "offset", 1, NULL, 'o' },
 425         { "read-only", 0, NULL, 'r' },
 426         { "partition", 1, NULL, 'P' },
 427         { "connect", 1, NULL, 'c' },
 428         { "disconnect", 0, NULL, 'd' },
 429         { "snapshot", 0, NULL, 's' },
 430         { "load-snapshot", 1, NULL, 'l' },
 431         { "nocache", 0, NULL, 'n' },
 432         { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
 433         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 434         { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
 435         { "detect-zeroes", 1, NULL, QEMU_NBD_OPT_DETECT_ZEROES },
 436         { "shared", 1, NULL, 'e' },
 437         { "format", 1, NULL, 'f' },
 438         { "persistent", 0, NULL, 't' },
 439         { "verbose", 0, NULL, 'v' },
 440         { "object", 1, NULL, QEMU_NBD_OPT_OBJECT },
 441         { "export-name", 1, NULL, 'x' },
 442         { NULL, 0, NULL, 0 }
 443     };
 444     int ch;
 445     int opt_ind = 0;
 446     char *end;
 447     int flags = BDRV_O_RDWR;
 448     int partition = -1;
 449     int ret = 0;
 450     bool seen_cache = false;
 451     bool seen_discard = false;
 452     bool seen_aio = false;
 453     pthread_t client_thread;
 454     const char *fmt = NULL;
 455     Error *local_err = NULL;
 456     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 457     QDict *options = NULL;
 458     const char *export_name = NULL;
 459
 460     /* The client thread uses SIGTERM to interrupt the server.  A signal
 461      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 462      */
 463     struct sigaction sa_sigterm;
 464     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 465     sa_sigterm.sa_handler = termsig_handler;
 466     sigaction(SIGTERM, &sa_sigterm, NULL);
 467     module_call_init(MODULE_INIT_QOM);
 468     qemu_add_opts(&qemu_object_opts);
 469     qemu_init_exec_dir(argv[0]);
 470
 471     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 472         switch (ch) {
 473         case 's':
 474             flags |= BDRV_O_SNAPSHOT;
 475             break;
 476         case 'n':
 477             optarg = (char *) "none";
 478             /* fallthrough */
 479         case QEMU_NBD_OPT_CACHE:
 480             if (seen_cache) {
 481                 error_report("-n and --cache can only be specified once");
 482                 exit(EXIT_FAILURE);
 483             }
 484             seen_cache = true;
 485             if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
 486                 error_report("Invalid cache mode `%s'", optarg);
 487                 exit(EXIT_FAILURE);
 488             }
 489             break;
 490         case QEMU_NBD_OPT_AIO:
 491             if (seen_aio) {
 492                 error_report("--aio can only be specified once");
 493                 exit(EXIT_FAILURE);
 494             }
 495             seen_aio = true;
 496             if (!strcmp(optarg, "native")) {
 497                 flags |= BDRV_O_NATIVE_AIO;
 498             } else if (!strcmp(optarg, "threads")) {
 499                 /* this is the default */
 500             } else {
 501                error_report("invalid aio mode `%s'", optarg);
 502                exit(EXIT_FAILURE);
 503             }
 504             break;
 505         case QEMU_NBD_OPT_DISCARD:
 506             if (seen_discard) {
 507                 error_report("--discard can only be specified once");
 508                 exit(EXIT_FAILURE);
 509             }
 510             seen_discard = true;
 511             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 512                 error_report("Invalid discard mode `%s'", optarg);
 513                 exit(EXIT_FAILURE);
 514             }
 515             break;
 516         case QEMU_NBD_OPT_DETECT_ZEROES:
 517             detect_zeroes =
 518                 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
 519                                 optarg,
 520                                 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
 521                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 522                                 &local_err);
 523             if (local_err) {
 524                 error_reportf_err(local_err,
 525                                   "Failed to parse detect_zeroes mode: ");
 526                 exit(EXIT_FAILURE);
 527             }
 528             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 529                 !(flags & BDRV_O_UNMAP)) {
 530                 error_report("setting detect-zeroes to unmap is not allowed "
 531                              "without setting discard operation to unmap");
 532                 exit(EXIT_FAILURE);
 533             }
 534             break;
 535         case 'b':
 536             bindto = optarg;
 537             break;
 538         case 'p':
 539             port = optarg;
 540             break;
 541         case 'o':
 542                 dev_offset = strtoll (optarg, &end, 0);
 543             if (*end) {
 544                 error_report("Invalid offset `%s'", optarg);
 545                 exit(EXIT_FAILURE);
 546             }
 547             if (dev_offset < 0) {
 548                 error_report("Offset must be positive `%s'", optarg);
 549                 exit(EXIT_FAILURE);
 550             }
 551             break;
 552         case 'l':
 553             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 554                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 555                                                   optarg, false);
 556                 if (!sn_opts) {
 557                     error_report("Failed in parsing snapshot param `%s'",
 558                                  optarg);
 559                     exit(EXIT_FAILURE);
 560                 }
 561             } else {
 562                 sn_id_or_name = optarg;
 563             }
 564             /* fall through */
 565         case 'r':
 566             nbdflags |= NBD_FLAG_READ_ONLY;
 567             flags &= ~BDRV_O_RDWR;
 568             break;
 569         case 'P':
 570             partition = strtol(optarg, &end, 0);
 571             if (*end) {
 572                 error_report("Invalid partition `%s'", optarg);
 573                 exit(EXIT_FAILURE);
 574             }
 575             if (partition < 1 || partition > 8) {
 576                 error_report("Invalid partition %d", partition);
 577                 exit(EXIT_FAILURE);
 578             }
 579             break;
 580         case 'k':
 581             sockpath = optarg;
 582             if (sockpath[0] != '/') {
 583                 error_report("socket path must be absolute");
 584                 exit(EXIT_FAILURE);
 585             }
 586             break;
 587         case 'd':
 588             disconnect = true;
 589             break;
 590         case 'c':
 591             device = optarg;
 592             break;
 593         case 'e':
 594             shared = strtol(optarg, &end, 0);
 595             if (*end) {
 596                 error_report("Invalid shared device number '%s'", optarg);
 597                 exit(EXIT_FAILURE);
 598             }
 599             if (shared < 1) {
 600                 error_report("Shared device number must be greater than 0");
 601                 exit(EXIT_FAILURE);
 602             }
 603             break;
 604         case 'f':
 605             fmt = optarg;
 606             break;
 607         case 't':
 608             persistent = 1;
 609             break;
 610         case 'x':
 611             export_name = optarg;
 612             break;
 613         case 'v':
 614             verbose = 1;
 615             break;
 616         case 'V':
 617             version(argv[0]);
 618             exit(0);
 619             break;
 620         case 'h':
 621             usage(argv[0]);
 622             exit(0);
 623             break;
 624         case '?':
 625             error_report("Try `%s --help' for more information.", argv[0]);
 626             exit(EXIT_FAILURE);
 627         case QEMU_NBD_OPT_OBJECT: {
 628             QemuOpts *opts;
 629             opts = qemu_opts_parse_noisily(&qemu_object_opts,
 630                                            optarg, true);
 631             if (!opts) {
 632                 exit(EXIT_FAILURE);
 633             }
 634         }   break;
 635         }
 636     }
 637
 638     if ((argc - optind) != 1) {
 639         error_report("Invalid number of arguments");
 640         error_printf("Try `%s --help' for more information.\n", argv[0]);
 641         exit(EXIT_FAILURE);
 642     }
 643
 644     if (qemu_opts_foreach(&qemu_object_opts,
 645                           user_creatable_add_opts_foreach,
 646                           NULL, &local_err)) {
 647         error_report_err(local_err);
 648         exit(EXIT_FAILURE);
 649     }
 650
 651     if (disconnect) {
 652         int nbdfd = open(argv[optind], O_RDWR);
 653         if (nbdfd < 0) {
 654             error_report("Cannot open %s: %s", argv[optind],
 655                          strerror(errno));
 656             exit(EXIT_FAILURE);
 657         }
 658         nbd_disconnect(nbdfd);
 659
 660         close(nbdfd);
 661
 662         printf("%s disconnected\n", argv[optind]);
 663
 664         return 0;
 665     }
 666
 667     if (device && !verbose) {
 668         int stderr_fd[2];
 669         pid_t pid;
 670         int ret;
 671
 672         if (qemu_pipe(stderr_fd) < 0) {
 673             error_report("Error setting up communication pipe: %s",
 674                          strerror(errno));
 675             exit(EXIT_FAILURE);
 676         }
 677
 678         /* Now daemonize, but keep a communication channel open to
 679          * print errors and exit with the proper status code.
 680          */
 681         pid = fork();
 682         if (pid < 0) {
 683             error_report("Failed to fork: %s", strerror(errno));
 684             exit(EXIT_FAILURE);
 685         } else if (pid == 0) {
 686             close(stderr_fd[0]);
 687             ret = qemu_daemon(1, 0);
 688
 689             /* Temporarily redirect stderr to the parent's pipe...  */
 690             dup2(stderr_fd[1], STDERR_FILENO);
 691             if (ret < 0) {
 692                 error_report("Failed to daemonize: %s", strerror(errno));
 693                 exit(EXIT_FAILURE);
 694             }
 695
 696             /* ... close the descriptor we inherited and go on.  */
 697             close(stderr_fd[1]);
 698         } else {
 699             bool errors = false;
 700             char *buf;
 701
 702             /* In the parent.  Print error messages from the child until
 703              * it closes the pipe.
 704              */
 705             close(stderr_fd[1]);
 706             buf = g_malloc(1024);
 707             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 708                 errors = true;
 709                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 710                 if (ret < 0) {
 711                     exit(EXIT_FAILURE);
 712                 }
 713             }
 714             if (ret < 0) {
 715                 error_report("Cannot read from daemon: %s",
 716                              strerror(errno));
 717                 exit(EXIT_FAILURE);
 718             }
 719
 720             /* Usually the daemon should not print any message.
 721              * Exit with zero status in that case.
 722              */
 723             exit(errors);
 724         }
 725     }
 726
 727     if (device != NULL && sockpath == NULL) {
 728         sockpath = g_malloc(128);
 729         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 730     }
 731
 732     saddr = nbd_build_socket_address(sockpath, bindto, port);
 733
 734     if (qemu_init_main_loop(&local_err)) {
 735         error_report_err(local_err);
 736         exit(EXIT_FAILURE);
 737     }
 738     bdrv_init();
 739     atexit(bdrv_close_all);
 740
 741     if (fmt) {
 742         options = qdict_new();
 743         qdict_put(options, "driver", qstring_from_str(fmt));
 744     }
 745
 746     srcpath = argv[optind];
 747     blk = blk_new_open("hda", srcpath, NULL, options, flags, &local_err);
 748     if (!blk) {
 749         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
 750                           argv[optind]);
 751         exit(EXIT_FAILURE);
 752     }
 753     bs = blk_bs(blk);
 754
 755     if (sn_opts) {
 756         ret = bdrv_snapshot_load_tmp(bs,
 757                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 758                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 759                                      &local_err);
 760     } else if (sn_id_or_name) {
 761         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 762                                                    &local_err);
 763     }
 764     if (ret < 0) {
 765         error_reportf_err(local_err, "Failed to load snapshot: ");
 766         exit(EXIT_FAILURE);
 767     }
 768
 769     bs->detect_zeroes = detect_zeroes;
 770     fd_size = blk_getlength(blk);
 771     if (fd_size < 0) {
 772         error_report("Failed to determine the image length: %s",
 773                      strerror(-fd_size));
 774         exit(EXIT_FAILURE);
 775     }
 776
 777     if (partition != -1) {
 778         ret = find_partition(blk, partition, &dev_offset, &fd_size);
 779         if (ret < 0) {
 780             error_report("Could not find partition %d: %s", partition,
 781                          strerror(-ret));
 782             exit(EXIT_FAILURE);
 783         }
 784     }
 785
 786     exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
 787                          &local_err);
 788     if (!exp) {
 789         error_report_err(local_err);
 790         exit(EXIT_FAILURE);
 791     }
 792     if (export_name) {
 793         nbd_export_set_name(exp, export_name);
 794         newproto = true;
 795     }
 796
 797     server_ioc = qio_channel_socket_new();
 798     if (qio_channel_socket_listen_sync(server_ioc, saddr, &local_err) < 0) {
 799         object_unref(OBJECT(server_ioc));
 800         error_report_err(local_err);
 801         return 1;
 802     }
 803
 804     if (device) {
 805         int ret;
 806
 807         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
 808         if (ret != 0) {
 809             error_report("Failed to create client thread: %s", strerror(ret));
 810             exit(EXIT_FAILURE);
 811         }
 812     } else {
 813         /* Shut up GCC warnings.  */
 814         memset(&client_thread, 0, sizeof(client_thread));
 815     }
 816
 817     nbd_update_server_watch();
 818
 819     /* now when the initialization is (almost) complete, chdir("/")
 820      * to free any busy filesystems */
 821     if (chdir("/") < 0) {
 822         error_report("Could not chdir to root directory: %s",
 823                      strerror(errno));
 824         exit(EXIT_FAILURE);
 825     }
 826
 827     state = RUNNING;
 828     do {
 829         main_loop_wait(false);
 830         if (state == TERMINATE) {
 831             state = TERMINATING;
 832             nbd_export_close(exp);
 833             nbd_export_put(exp);
 834             exp = NULL;
 835         }
 836     } while (state != TERMINATED);
 837
 838     blk_unref(blk);
 839     if (sockpath) {
 840         unlink(sockpath);
 841     }
 842
 843     qemu_opts_del(sn_opts);
 844
 845     if (device) {
 846         void *ret;
 847         pthread_join(client_thread, &ret);
 848         exit(ret != NULL);
 849     } else {
 850         exit(EXIT_SUCCESS);
 851     }
 852 }