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