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 <getopt.h>
  21 #include <libgen.h>
  22 #include <pthread.h>
  23
  24 #include "qemu-common.h"
  25 #include "qapi/error.h"
  26 #include "qemu/cutils.h"
  27 #include "sysemu/block-backend.h"
  28 #include "sysemu/runstate.h" /* for qemu_system_killed() prototype */
  29 #include "block/block_int.h"
  30 #include "block/nbd.h"
  31 #include "qemu/main-loop.h"
  32 #include "qemu/module.h"
  33 #include "qemu/option.h"
  34 #include "qemu/error-report.h"
  35 #include "qemu/config-file.h"
  36 #include "qemu/bswap.h"
  37 #include "qemu/log.h"
  38 #include "qemu/systemd.h"
  39 #include "block/snapshot.h"
  40 #include "qapi/qmp/qdict.h"
  41 #include "qapi/qmp/qstring.h"
  42 #include "qom/object_interfaces.h"
  43 #include "io/channel-socket.h"
  44 #include "io/net-listener.h"
  45 #include "crypto/init.h"
  46 #include "trace/control.h"
  47 #include "qemu-version.h"
  48
  49 #ifdef __linux__
  50 #define HAVE_NBD_DEVICE 1
  51 #else
  52 #define HAVE_NBD_DEVICE 0
  53 #endif
  54
  55 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  56 #define QEMU_NBD_OPT_CACHE         256
  57 #define QEMU_NBD_OPT_AIO           257
  58 #define QEMU_NBD_OPT_DISCARD       258
  59 #define QEMU_NBD_OPT_DETECT_ZEROES 259
  60 #define QEMU_NBD_OPT_OBJECT        260
  61 #define QEMU_NBD_OPT_TLSCREDS      261
  62 #define QEMU_NBD_OPT_IMAGE_OPTS    262
  63 #define QEMU_NBD_OPT_FORK          263
  64 #define QEMU_NBD_OPT_TLSAUTHZ      264
  65 #define QEMU_NBD_OPT_PID_FILE      265
  66
  67 #define MBR_SIZE 512
  68
  69 static int verbose;
  70 static char *srcpath;
  71 static SocketAddress *saddr;
  72 static int persistent = 0;
  73 static enum { RUNNING, TERMINATE, TERMINATED } state;
  74 static int shared = 1;
  75 static int nb_fds;
  76 static QIONetListener *server;
  77 static QCryptoTLSCreds *tlscreds;
  78 static const char *tlsauthz;
  79
  80 static void usage(const char *name)
  81 {
  82     (printf) (
  83 "Usage: %s [OPTIONS] FILE\n"
  84 "  or:  %s -L [OPTIONS]\n"
  85 "QEMU Disk Network Block Device Utility\n"
  86 "\n"
  87 "  -h, --help                display this help and exit\n"
  88 "  -V, --version             output version information and exit\n"
  89 "\n"
  90 "Connection properties:\n"
  91 "  -p, --port=PORT           port to listen on (default `%d')\n"
  92 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  93 "  -k, --socket=PATH         path to the unix socket\n"
  94 "                            (default '"SOCKET_PATH"')\n"
  95 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  96 "  -t, --persistent          don't exit on the last connection\n"
  97 "  -v, --verbose             display extra debugging information\n"
  98 "  -x, --export-name=NAME    expose export by name (default is empty string)\n"
  99 "  -D, --description=TEXT    export a human-readable description\n"
 100 "\n"
 101 "Exposing part of the image:\n"
 102 "  -o, --offset=OFFSET       offset into the image\n"
 103 "  -A, --allocation-depth    expose the allocation depth\n"
 104 "  -B, --bitmap=NAME         expose a persistent dirty bitmap\n"
 105 "\n"
 106 "General purpose options:\n"
 107 "  -L, --list                list exports available from another NBD server\n"
 108 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
 109 "                            passwords and/or encryption keys\n"
 110 "  --tls-creds=ID            use id of an earlier --object to provide TLS\n"
 111 "  --tls-authz=ID            use id of an earlier --object to provide\n"
 112 "                            authorization\n"
 113 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
 114 "                            specify tracing options\n"
 115 "  --fork                    fork off the server process and exit the parent\n"
 116 "                            once the server is running\n"
 117 "  --pid-file=PATH           store the server's process ID in the given file\n"
 118 #if HAVE_NBD_DEVICE
 119 "\n"
 120 "Kernel NBD client support:\n"
 121 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
 122 "  -d, --disconnect          disconnect the specified device\n"
 123 #endif
 124 "\n"
 125 "Block device options:\n"
 126 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
 127 "  -r, --read-only           export read-only\n"
 128 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
 129 "                            file with backing_file=FILE, redirect the write to\n"
 130 "                            the temporary one\n"
 131 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 132 "                            load an internal snapshot inside FILE and export it\n"
 133 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
 134 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 135 "                            '[ID_OR_NAME]'\n"
 136 "  -n, --nocache             disable host cache\n"
 137 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
 138 "      --aio=MODE            set AIO mode (native, io_uring or threads)\n"
 139 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 140 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 141 "      --image-opts          treat FILE as a full set of image options\n"
 142 "\n"
 143 QEMU_HELP_BOTTOM "\n"
 144     , name, name, NBD_DEFAULT_PORT, "DEVICE");
 145 }
 146
 147 static void version(const char *name)
 148 {
 149     printf(
 150 "%s " QEMU_FULL_VERSION "\n"
 151 "Written by Anthony Liguori.\n"
 152 "\n"
 153 QEMU_COPYRIGHT "\n"
 154 "This is free software; see the source for copying conditions.  There is NO\n"
 155 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 156     , name);
 157 }
 158
 159 #ifdef CONFIG_POSIX
 160 /*
 161  * The client thread uses SIGTERM to interrupt the server.  A signal
 162  * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 163  */
 164 void qemu_system_killed(int signum, pid_t pid)
 165 {
 166     qatomic_cmpxchg(&state, RUNNING, TERMINATE);
 167     qemu_notify_event();
 168 }
 169 #endif /* CONFIG_POSIX */
 170
 171 static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
 172                                 const char *hostname)
 173 {
 174     int ret = EXIT_FAILURE;
 175     int rc;
 176     Error *err = NULL;
 177     QIOChannelSocket *sioc;
 178     NBDExportInfo *list;
 179     int i, j;
 180
 181     sioc = qio_channel_socket_new();
 182     if (qio_channel_socket_connect_sync(sioc, saddr, &err) < 0) {
 183         error_report_err(err);
 184         goto out;
 185     }
 186     rc = nbd_receive_export_list(QIO_CHANNEL(sioc), tls, hostname, &list,
 187                                  &err);
 188     if (rc < 0) {
 189         if (err) {
 190             error_report_err(err);
 191         }
 192         goto out;
 193     }
 194     printf("exports available: %d\n", rc);
 195     for (i = 0; i < rc; i++) {
 196         printf(" export: '%s'\n", list[i].name);
 197         if (list[i].description && *list[i].description) {
 198             printf("  description: %s\n", list[i].description);
 199         }
 200         if (list[i].flags & NBD_FLAG_HAS_FLAGS) {
 201             static const char *const flag_names[] = {
 202                 [NBD_FLAG_READ_ONLY_BIT]            = "readonly",
 203                 [NBD_FLAG_SEND_FLUSH_BIT]           = "flush",
 204                 [NBD_FLAG_SEND_FUA_BIT]             = "fua",
 205                 [NBD_FLAG_ROTATIONAL_BIT]           = "rotational",
 206                 [NBD_FLAG_SEND_TRIM_BIT]            = "trim",
 207                 [NBD_FLAG_SEND_WRITE_ZEROES_BIT]    = "zeroes",
 208                 [NBD_FLAG_SEND_DF_BIT]              = "df",
 209                 [NBD_FLAG_CAN_MULTI_CONN_BIT]       = "multi",
 210                 [NBD_FLAG_SEND_RESIZE_BIT]          = "resize",
 211                 [NBD_FLAG_SEND_CACHE_BIT]           = "cache",
 212                 [NBD_FLAG_SEND_FAST_ZERO_BIT]       = "fast-zero",
 213             };
 214
 215             printf("  size:  %" PRIu64 "\n", list[i].size);
 216             printf("  flags: 0x%x (", list[i].flags);
 217             for (size_t bit = 0; bit < ARRAY_SIZE(flag_names); bit++) {
 218                 if (flag_names[bit] && (list[i].flags & (1 << bit))) {
 219                     printf(" %s", flag_names[bit]);
 220                 }
 221             }
 222             printf(" )\n");
 223         }
 224         if (list[i].min_block) {
 225             printf("  min block: %u\n", list[i].min_block);
 226             printf("  opt block: %u\n", list[i].opt_block);
 227             printf("  max block: %u\n", list[i].max_block);
 228         }
 229         if (list[i].n_contexts) {
 230             printf("  available meta contexts: %d\n", list[i].n_contexts);
 231             for (j = 0; j < list[i].n_contexts; j++) {
 232                 printf("   %s\n", list[i].contexts[j]);
 233             }
 234         }
 235     }
 236     nbd_free_export_list(list, rc);
 237
 238     ret = EXIT_SUCCESS;
 239  out:
 240     object_unref(OBJECT(sioc));
 241     return ret;
 242 }
 243
 244
 245 #if HAVE_NBD_DEVICE
 246 static void *show_parts(void *arg)
 247 {
 248     char *device = arg;
 249     int nbd;
 250
 251     /* linux just needs an open() to trigger
 252      * the partition table update
 253      * but remember to load the module with max_part != 0 :
 254      *     modprobe nbd max_part=63
 255      */
 256     nbd = open(device, O_RDWR);
 257     if (nbd >= 0) {
 258         close(nbd);
 259     }
 260     return NULL;
 261 }
 262
 263 static void *nbd_client_thread(void *arg)
 264 {
 265     char *device = arg;
 266     NBDExportInfo info = { .request_sizes = false, .name = g_strdup("") };
 267     QIOChannelSocket *sioc;
 268     int fd = -1;
 269     int ret = EXIT_FAILURE;
 270     pthread_t show_parts_thread;
 271     Error *local_error = NULL;
 272
 273     sioc = qio_channel_socket_new();
 274     if (qio_channel_socket_connect_sync(sioc,
 275                                         saddr,
 276                                         &local_error) < 0) {
 277         error_report_err(local_error);
 278         goto out;
 279     }
 280
 281     if (nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
 282                               NULL, NULL, NULL, &info, &local_error) < 0) {
 283         if (local_error) {
 284             error_report_err(local_error);
 285         }
 286         goto out;
 287     }
 288
 289     fd = open(device, O_RDWR);
 290     if (fd < 0) {
 291         /* Linux-only, we can use %m in printf.  */
 292         error_report("Failed to open %s: %m", device);
 293         goto out;
 294     }
 295
 296     if (nbd_init(fd, sioc, &info, &local_error) < 0) {
 297         error_report_err(local_error);
 298         goto out;
 299     }
 300
 301     /* update partition table */
 302     pthread_create(&show_parts_thread, NULL, show_parts, device);
 303
 304     if (verbose) {
 305         fprintf(stderr, "NBD device %s is now connected to %s\n",
 306                 device, srcpath);
 307     } else {
 308         /* Close stderr so that the qemu-nbd process exits.  */
 309         dup2(STDOUT_FILENO, STDERR_FILENO);
 310     }
 311
 312     if (nbd_client(fd) < 0) {
 313         goto out;
 314     }
 315
 316     ret = EXIT_SUCCESS;
 317
 318  out:
 319     if (fd >= 0) {
 320         close(fd);
 321     }
 322     object_unref(OBJECT(sioc));
 323     g_free(info.name);
 324     kill(getpid(), SIGTERM);
 325     return (void *) (intptr_t) ret;
 326 }
 327 #endif /* HAVE_NBD_DEVICE */
 328
 329 static int nbd_can_accept(void)
 330 {
 331     return state == RUNNING && (shared == 0 || nb_fds < shared);
 332 }
 333
 334 static void nbd_update_server_watch(void);
 335
 336 static void nbd_client_closed(NBDClient *client, bool negotiated)
 337 {
 338     nb_fds--;
 339     if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
 340         state = TERMINATE;
 341     }
 342     nbd_update_server_watch();
 343     nbd_client_put(client);
 344 }
 345
 346 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
 347                        gpointer opaque)
 348 {
 349     if (state >= TERMINATE) {
 350         return;
 351     }
 352
 353     nb_fds++;
 354     nbd_update_server_watch();
 355     nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
 356 }
 357
 358 static void nbd_update_server_watch(void)
 359 {
 360     if (nbd_can_accept()) {
 361         qio_net_listener_set_client_func(server, nbd_accept, NULL, NULL);
 362     } else {
 363         qio_net_listener_set_client_func(server, NULL, NULL, NULL);
 364     }
 365 }
 366
 367
 368 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 369                                                const char *bindto,
 370                                                const char *port)
 371 {
 372     SocketAddress *saddr;
 373
 374     saddr = g_new0(SocketAddress, 1);
 375     if (sockpath) {
 376         saddr->type = SOCKET_ADDRESS_TYPE_UNIX;
 377         saddr->u.q_unix.path = g_strdup(sockpath);
 378     } else {
 379         InetSocketAddress *inet;
 380         saddr->type = SOCKET_ADDRESS_TYPE_INET;
 381         inet = &saddr->u.inet;
 382         inet->host = g_strdup(bindto);
 383         if (port) {
 384             inet->port = g_strdup(port);
 385         } else  {
 386             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 387         }
 388     }
 389
 390     return saddr;
 391 }
 392
 393
 394 static QemuOptsList file_opts = {
 395     .name = "file",
 396     .implied_opt_name = "file",
 397     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 398     .desc = {
 399         /* no elements => accept any params */
 400         { /* end of list */ }
 401     },
 402 };
 403
 404 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list,
 405                                           Error **errp)
 406 {
 407     Object *obj;
 408     QCryptoTLSCreds *creds;
 409
 410     obj = object_resolve_path_component(
 411         object_get_objects_root(), id);
 412     if (!obj) {
 413         error_setg(errp, "No TLS credentials with id '%s'",
 414                    id);
 415         return NULL;
 416     }
 417     creds = (QCryptoTLSCreds *)
 418         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 419     if (!creds) {
 420         error_setg(errp, "Object with id '%s' is not TLS credentials",
 421                    id);
 422         return NULL;
 423     }
 424
 425     if (list) {
 426         if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
 427             error_setg(errp,
 428                        "Expecting TLS credentials with a client endpoint");
 429             return NULL;
 430         }
 431     } else {
 432         if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
 433             error_setg(errp,
 434                        "Expecting TLS credentials with a server endpoint");
 435             return NULL;
 436         }
 437     }
 438     object_ref(obj);
 439     return creds;
 440 }
 441
 442 static void setup_address_and_port(const char **address, const char **port)
 443 {
 444     if (*address == NULL) {
 445         *address = "0.0.0.0";
 446     }
 447
 448     if (*port == NULL) {
 449         *port = stringify(NBD_DEFAULT_PORT);
 450     }
 451 }
 452
 453 /*
 454  * Check socket parameters compatibility when socket activation is used.
 455  */
 456 static const char *socket_activation_validate_opts(const char *device,
 457                                                    const char *sockpath,
 458                                                    const char *address,
 459                                                    const char *port,
 460                                                    bool list)
 461 {
 462     if (device != NULL) {
 463         return "NBD device can't be set when using socket activation";
 464     }
 465
 466     if (sockpath != NULL) {
 467         return "Unix socket can't be set when using socket activation";
 468     }
 469
 470     if (address != NULL) {
 471         return "The interface can't be set when using socket activation";
 472     }
 473
 474     if (port != NULL) {
 475         return "TCP port number can't be set when using socket activation";
 476     }
 477
 478     if (list) {
 479         return "List mode is incompatible with socket activation";
 480     }
 481
 482     return NULL;
 483 }
 484
 485 static void qemu_nbd_shutdown(void)
 486 {
 487     job_cancel_sync_all();
 488     blk_exp_close_all();
 489     bdrv_close_all();
 490 }
 491
 492 int main(int argc, char **argv)
 493 {
 494     BlockBackend *blk;
 495     BlockDriverState *bs;
 496     uint64_t dev_offset = 0;
 497     bool readonly = false;
 498     bool disconnect = false;
 499     const char *bindto = NULL;
 500     const char *port = NULL;
 501     char *sockpath = NULL;
 502     char *device = NULL;
 503     QemuOpts *sn_opts = NULL;
 504     const char *sn_id_or_name = NULL;
 505     const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:AB:L";
 506     struct option lopt[] = {
 507         { "help", no_argument, NULL, 'h' },
 508         { "version", no_argument, NULL, 'V' },
 509         { "bind", required_argument, NULL, 'b' },
 510         { "port", required_argument, NULL, 'p' },
 511         { "socket", required_argument, NULL, 'k' },
 512         { "offset", required_argument, NULL, 'o' },
 513         { "read-only", no_argument, NULL, 'r' },
 514         { "allocation-depth", no_argument, NULL, 'A' },
 515         { "bitmap", required_argument, NULL, 'B' },
 516         { "connect", required_argument, NULL, 'c' },
 517         { "disconnect", no_argument, NULL, 'd' },
 518         { "list", no_argument, NULL, 'L' },
 519         { "snapshot", no_argument, NULL, 's' },
 520         { "load-snapshot", required_argument, NULL, 'l' },
 521         { "nocache", no_argument, NULL, 'n' },
 522         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 523         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 524         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 525         { "detect-zeroes", required_argument, NULL,
 526           QEMU_NBD_OPT_DETECT_ZEROES },
 527         { "shared", required_argument, NULL, 'e' },
 528         { "format", required_argument, NULL, 'f' },
 529         { "persistent", no_argument, NULL, 't' },
 530         { "verbose", no_argument, NULL, 'v' },
 531         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 532         { "export-name", required_argument, NULL, 'x' },
 533         { "description", required_argument, NULL, 'D' },
 534         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 535         { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
 536         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 537         { "trace", required_argument, NULL, 'T' },
 538         { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
 539         { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE },
 540         { NULL, 0, NULL, 0 }
 541     };
 542     int ch;
 543     int opt_ind = 0;
 544     int flags = BDRV_O_RDWR;
 545     int ret = 0;
 546     bool seen_cache = false;
 547     bool seen_discard = false;
 548     bool seen_aio = false;
 549     pthread_t client_thread;
 550     const char *fmt = NULL;
 551     Error *local_err = NULL;
 552     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 553     QDict *options = NULL;
 554     const char *export_name = NULL; /* defaults to "" later for server mode */
 555     const char *export_description = NULL;
 556     strList *bitmaps = NULL;
 557     bool alloc_depth = false;
 558     const char *tlscredsid = NULL;
 559     bool imageOpts = false;
 560     bool writethrough = true;
 561     bool fork_process = false;
 562     bool list = false;
 563     int old_stderr = -1;
 564     unsigned socket_activation;
 565     const char *pid_file_name = NULL;
 566     BlockExportOptions *export_opts;
 567
 568 #ifdef CONFIG_POSIX
 569     os_setup_early_signal_handling();
 570     os_setup_signal_handling();
 571 #endif
 572
 573     socket_init();
 574     error_init(argv[0]);
 575     module_call_init(MODULE_INIT_TRACE);
 576     qcrypto_init(&error_fatal);
 577
 578     module_call_init(MODULE_INIT_QOM);
 579     qemu_add_opts(&qemu_trace_opts);
 580     qemu_init_exec_dir(argv[0]);
 581
 582     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 583         switch (ch) {
 584         case 's':
 585             flags |= BDRV_O_SNAPSHOT;
 586             break;
 587         case 'n':
 588             optarg = (char *) "none";
 589             /* fallthrough */
 590         case QEMU_NBD_OPT_CACHE:
 591             if (seen_cache) {
 592                 error_report("-n and --cache can only be specified once");
 593                 exit(EXIT_FAILURE);
 594             }
 595             seen_cache = true;
 596             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 597                 error_report("Invalid cache mode `%s'", optarg);
 598                 exit(EXIT_FAILURE);
 599             }
 600             break;
 601         case QEMU_NBD_OPT_AIO:
 602             if (seen_aio) {
 603                 error_report("--aio can only be specified once");
 604                 exit(EXIT_FAILURE);
 605             }
 606             seen_aio = true;
 607             if (bdrv_parse_aio(optarg, &flags) < 0) {
 608                 error_report("Invalid aio mode '%s'", optarg);
 609                 exit(EXIT_FAILURE);
 610             }
 611             break;
 612         case QEMU_NBD_OPT_DISCARD:
 613             if (seen_discard) {
 614                 error_report("--discard can only be specified once");
 615                 exit(EXIT_FAILURE);
 616             }
 617             seen_discard = true;
 618             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 619                 error_report("Invalid discard mode `%s'", optarg);
 620                 exit(EXIT_FAILURE);
 621             }
 622             break;
 623         case QEMU_NBD_OPT_DETECT_ZEROES:
 624             detect_zeroes =
 625                 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
 626                                 optarg,
 627                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 628                                 &local_err);
 629             if (local_err) {
 630                 error_reportf_err(local_err,
 631                                   "Failed to parse detect_zeroes mode: ");
 632                 exit(EXIT_FAILURE);
 633             }
 634             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 635                 !(flags & BDRV_O_UNMAP)) {
 636                 error_report("setting detect-zeroes to unmap is not allowed "
 637                              "without setting discard operation to unmap");
 638                 exit(EXIT_FAILURE);
 639             }
 640             break;
 641         case 'b':
 642             bindto = optarg;
 643             break;
 644         case 'p':
 645             port = optarg;
 646             break;
 647         case 'o':
 648             if (qemu_strtou64(optarg, NULL, 0, &dev_offset) < 0) {
 649                 error_report("Invalid offset '%s'", optarg);
 650                 exit(EXIT_FAILURE);
 651             }
 652             break;
 653         case 'l':
 654             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 655                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 656                                                   optarg, false);
 657                 if (!sn_opts) {
 658                     error_report("Failed in parsing snapshot param `%s'",
 659                                  optarg);
 660                     exit(EXIT_FAILURE);
 661                 }
 662             } else {
 663                 sn_id_or_name = optarg;
 664             }
 665             /* fall through */
 666         case 'r':
 667             readonly = true;
 668             flags &= ~BDRV_O_RDWR;
 669             break;
 670         case 'A':
 671             alloc_depth = true;
 672             break;
 673         case 'B':
 674             QAPI_LIST_PREPEND(bitmaps, g_strdup(optarg));
 675             break;
 676         case 'k':
 677             sockpath = optarg;
 678             if (sockpath[0] != '/') {
 679                 error_report("socket path must be absolute");
 680                 exit(EXIT_FAILURE);
 681             }
 682             break;
 683         case 'd':
 684             disconnect = true;
 685             break;
 686         case 'c':
 687             device = optarg;
 688             break;
 689         case 'e':
 690             if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
 691                 shared < 0) {
 692                 error_report("Invalid shared device number '%s'", optarg);
 693                 exit(EXIT_FAILURE);
 694             }
 695             break;
 696         case 'f':
 697             fmt = optarg;
 698             break;
 699         case 't':
 700             persistent = 1;
 701             break;
 702         case 'x':
 703             export_name = optarg;
 704             if (strlen(export_name) > NBD_MAX_STRING_SIZE) {
 705                 error_report("export name '%s' too long", export_name);
 706                 exit(EXIT_FAILURE);
 707             }
 708             break;
 709         case 'D':
 710             export_description = optarg;
 711             if (strlen(export_description) > NBD_MAX_STRING_SIZE) {
 712                 error_report("export description '%s' too long",
 713                              export_description);
 714                 exit(EXIT_FAILURE);
 715             }
 716             break;
 717         case 'v':
 718             verbose = 1;
 719             break;
 720         case 'V':
 721             version(argv[0]);
 722             exit(0);
 723             break;
 724         case 'h':
 725             usage(argv[0]);
 726             exit(0);
 727             break;
 728         case '?':
 729             error_report("Try `%s --help' for more information.", argv[0]);
 730             exit(EXIT_FAILURE);
 731         case QEMU_NBD_OPT_OBJECT:
 732             user_creatable_process_cmdline(optarg);
 733             break;
 734         case QEMU_NBD_OPT_TLSCREDS:
 735             tlscredsid = optarg;
 736             break;
 737         case QEMU_NBD_OPT_IMAGE_OPTS:
 738             imageOpts = true;
 739             break;
 740         case 'T':
 741             trace_opt_parse(optarg);
 742             break;
 743         case QEMU_NBD_OPT_TLSAUTHZ:
 744             tlsauthz = optarg;
 745             break;
 746         case QEMU_NBD_OPT_FORK:
 747             fork_process = true;
 748             break;
 749         case 'L':
 750             list = true;
 751             break;
 752         case QEMU_NBD_OPT_PID_FILE:
 753             pid_file_name = optarg;
 754             break;
 755         }
 756     }
 757
 758     if (list) {
 759         if (argc != optind) {
 760             error_report("List mode is incompatible with a file name");
 761             exit(EXIT_FAILURE);
 762         }
 763         if (export_name || export_description || dev_offset ||
 764             device || disconnect || fmt || sn_id_or_name || bitmaps ||
 765             alloc_depth || seen_aio || seen_discard || seen_cache) {
 766             error_report("List mode is incompatible with per-device settings");
 767             exit(EXIT_FAILURE);
 768         }
 769         if (fork_process) {
 770             error_report("List mode is incompatible with forking");
 771             exit(EXIT_FAILURE);
 772         }
 773     } else if ((argc - optind) != 1) {
 774         error_report("Invalid number of arguments");
 775         error_printf("Try `%s --help' for more information.\n", argv[0]);
 776         exit(EXIT_FAILURE);
 777     } else if (!export_name) {
 778         export_name = "";
 779     }
 780
 781     if (!trace_init_backends()) {
 782         exit(1);
 783     }
 784     trace_init_file();
 785     qemu_set_log(LOG_TRACE);
 786
 787     socket_activation = check_socket_activation();
 788     if (socket_activation == 0) {
 789         setup_address_and_port(&bindto, &port);
 790     } else {
 791         /* Using socket activation - check user didn't use -p etc. */
 792         const char *err_msg = socket_activation_validate_opts(device, sockpath,
 793                                                               bindto, port,
 794                                                               list);
 795         if (err_msg != NULL) {
 796             error_report("%s", err_msg);
 797             exit(EXIT_FAILURE);
 798         }
 799
 800         /* qemu-nbd can only listen on a single socket.  */
 801         if (socket_activation > 1) {
 802             error_report("qemu-nbd does not support socket activation with %s > 1",
 803                          "LISTEN_FDS");
 804             exit(EXIT_FAILURE);
 805         }
 806     }
 807
 808     if (tlscredsid) {
 809         if (sockpath) {
 810             error_report("TLS is only supported with IPv4/IPv6");
 811             exit(EXIT_FAILURE);
 812         }
 813         if (device) {
 814             error_report("TLS is not supported with a host device");
 815             exit(EXIT_FAILURE);
 816         }
 817         if (tlsauthz && list) {
 818             error_report("TLS authorization is incompatible with export list");
 819             exit(EXIT_FAILURE);
 820         }
 821         tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
 822         if (local_err) {
 823             error_reportf_err(local_err, "Failed to get TLS creds: ");
 824             exit(EXIT_FAILURE);
 825         }
 826     } else {
 827         if (tlsauthz) {
 828             error_report("--tls-authz is not permitted without --tls-creds");
 829             exit(EXIT_FAILURE);
 830         }
 831     }
 832
 833     if (list) {
 834         saddr = nbd_build_socket_address(sockpath, bindto, port);
 835         return qemu_nbd_client_list(saddr, tlscreds, bindto);
 836     }
 837
 838 #if !HAVE_NBD_DEVICE
 839     if (disconnect || device) {
 840         error_report("Kernel /dev/nbdN support not available");
 841         exit(EXIT_FAILURE);
 842     }
 843 #else /* HAVE_NBD_DEVICE */
 844     if (disconnect) {
 845         int nbdfd = open(argv[optind], O_RDWR);
 846         if (nbdfd < 0) {
 847             error_report("Cannot open %s: %s", argv[optind],
 848                          strerror(errno));
 849             exit(EXIT_FAILURE);
 850         }
 851         nbd_disconnect(nbdfd);
 852
 853         close(nbdfd);
 854
 855         printf("%s disconnected\n", argv[optind]);
 856
 857         return 0;
 858     }
 859 #endif
 860
 861     if ((device && !verbose) || fork_process) {
 862 #ifndef WIN32
 863         int stderr_fd[2];
 864         pid_t pid;
 865         int ret;
 866
 867         if (qemu_pipe(stderr_fd) < 0) {
 868             error_report("Error setting up communication pipe: %s",
 869                          strerror(errno));
 870             exit(EXIT_FAILURE);
 871         }
 872
 873         /* Now daemonize, but keep a communication channel open to
 874          * print errors and exit with the proper status code.
 875          */
 876         pid = fork();
 877         if (pid < 0) {
 878             error_report("Failed to fork: %s", strerror(errno));
 879             exit(EXIT_FAILURE);
 880         } else if (pid == 0) {
 881             close(stderr_fd[0]);
 882
 883             /* Remember parent's stderr if we will be restoring it. */
 884             if (fork_process) {
 885                 old_stderr = dup(STDERR_FILENO);
 886             }
 887
 888             ret = qemu_daemon(1, 0);
 889
 890             /* Temporarily redirect stderr to the parent's pipe...  */
 891             dup2(stderr_fd[1], STDERR_FILENO);
 892             if (ret < 0) {
 893                 error_report("Failed to daemonize: %s", strerror(errno));
 894                 exit(EXIT_FAILURE);
 895             }
 896
 897             /* ... close the descriptor we inherited and go on.  */
 898             close(stderr_fd[1]);
 899         } else {
 900             bool errors = false;
 901             char *buf;
 902
 903             /* In the parent.  Print error messages from the child until
 904              * it closes the pipe.
 905              */
 906             close(stderr_fd[1]);
 907             buf = g_malloc(1024);
 908             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 909                 errors = true;
 910                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 911                 if (ret < 0) {
 912                     exit(EXIT_FAILURE);
 913                 }
 914             }
 915             if (ret < 0) {
 916                 error_report("Cannot read from daemon: %s",
 917                              strerror(errno));
 918                 exit(EXIT_FAILURE);
 919             }
 920
 921             /* Usually the daemon should not print any message.
 922              * Exit with zero status in that case.
 923              */
 924             exit(errors);
 925         }
 926 #else /* WIN32 */
 927         error_report("Unable to fork into background on Windows hosts");
 928         exit(EXIT_FAILURE);
 929 #endif /* WIN32 */
 930     }
 931
 932     if (device != NULL && sockpath == NULL) {
 933         sockpath = g_malloc(128);
 934         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 935     }
 936
 937     server = qio_net_listener_new();
 938     if (socket_activation == 0) {
 939         int backlog;
 940
 941         if (persistent || shared == 0) {
 942             backlog = SOMAXCONN;
 943         } else {
 944             backlog = MIN(shared, SOMAXCONN);
 945         }
 946         saddr = nbd_build_socket_address(sockpath, bindto, port);
 947         if (qio_net_listener_open_sync(server, saddr, backlog,
 948                                        &local_err) < 0) {
 949             object_unref(OBJECT(server));
 950             error_report_err(local_err);
 951             exit(EXIT_FAILURE);
 952         }
 953     } else {
 954         size_t i;
 955         /* See comment in check_socket_activation above. */
 956         for (i = 0; i < socket_activation; i++) {
 957             QIOChannelSocket *sioc;
 958             sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
 959                                              &local_err);
 960             if (sioc == NULL) {
 961                 object_unref(OBJECT(server));
 962                 error_reportf_err(local_err,
 963                                   "Failed to use socket activation: ");
 964                 exit(EXIT_FAILURE);
 965             }
 966             qio_net_listener_add(server, sioc);
 967             object_unref(OBJECT(sioc));
 968         }
 969     }
 970
 971     if (qemu_init_main_loop(&local_err)) {
 972         error_report_err(local_err);
 973         exit(EXIT_FAILURE);
 974     }
 975     bdrv_init();
 976     atexit(qemu_nbd_shutdown);
 977
 978     srcpath = argv[optind];
 979     if (imageOpts) {
 980         QemuOpts *opts;
 981         if (fmt) {
 982             error_report("--image-opts and -f are mutually exclusive");
 983             exit(EXIT_FAILURE);
 984         }
 985         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
 986         if (!opts) {
 987             qemu_opts_reset(&file_opts);
 988             exit(EXIT_FAILURE);
 989         }
 990         options = qemu_opts_to_qdict(opts, NULL);
 991         qemu_opts_reset(&file_opts);
 992         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
 993     } else {
 994         if (fmt) {
 995             options = qdict_new();
 996             qdict_put_str(options, "driver", fmt);
 997         }
 998         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
 999     }
1000
1001     if (!blk) {
1002         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
1003                           argv[optind]);
1004         exit(EXIT_FAILURE);
1005     }
1006     bs = blk_bs(blk);
1007
1008     if (dev_offset) {
1009         QDict *raw_opts = qdict_new();
1010         qdict_put_str(raw_opts, "driver", "raw");
1011         qdict_put_str(raw_opts, "file", bs->node_name);
1012         qdict_put_int(raw_opts, "offset", dev_offset);
1013         bs = bdrv_open(NULL, NULL, raw_opts, flags, &error_fatal);
1014         blk_remove_bs(blk);
1015         blk_insert_bs(blk, bs, &error_fatal);
1016         bdrv_unref(bs);
1017     }
1018
1019     blk_set_enable_write_cache(blk, !writethrough);
1020
1021     if (sn_opts) {
1022         ret = bdrv_snapshot_load_tmp(bs,
1023                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
1024                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
1025                                      &local_err);
1026     } else if (sn_id_or_name) {
1027         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
1028                                                    &local_err);
1029     }
1030     if (ret < 0) {
1031         error_reportf_err(local_err, "Failed to load snapshot: ");
1032         exit(EXIT_FAILURE);
1033     }
1034
1035     bs->detect_zeroes = detect_zeroes;
1036
1037     nbd_server_is_qemu_nbd(true);
1038
1039     export_opts = g_new(BlockExportOptions, 1);
1040     *export_opts = (BlockExportOptions) {
1041         .type               = BLOCK_EXPORT_TYPE_NBD,
1042         .id                 = g_strdup("qemu-nbd-export"),
1043         .node_name          = g_strdup(bdrv_get_node_name(bs)),
1044         .has_writethrough   = true,
1045         .writethrough       = writethrough,
1046         .has_writable       = true,
1047         .writable           = !readonly,
1048         .u.nbd = {
1049             .has_name             = true,
1050             .name                 = g_strdup(export_name),
1051             .has_description      = !!export_description,
1052             .description          = g_strdup(export_description),
1053             .has_bitmaps          = !!bitmaps,
1054             .bitmaps              = bitmaps,
1055             .has_allocation_depth = alloc_depth,
1056             .allocation_depth     = alloc_depth,
1057         },
1058     };
1059     blk_exp_add(export_opts, &error_fatal);
1060     qapi_free_BlockExportOptions(export_opts);
1061
1062     if (device) {
1063 #if HAVE_NBD_DEVICE
1064         int ret;
1065
1066         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1067         if (ret != 0) {
1068             error_report("Failed to create client thread: %s", strerror(ret));
1069             exit(EXIT_FAILURE);
1070         }
1071 #endif
1072     } else {
1073         /* Shut up GCC warnings.  */
1074         memset(&client_thread, 0, sizeof(client_thread));
1075     }
1076
1077     nbd_update_server_watch();
1078
1079     if (pid_file_name) {
1080         qemu_write_pidfile(pid_file_name, &error_fatal);
1081     }
1082
1083     /* now when the initialization is (almost) complete, chdir("/")
1084      * to free any busy filesystems */
1085     if (chdir("/") < 0) {
1086         error_report("Could not chdir to root directory: %s",
1087                      strerror(errno));
1088         exit(EXIT_FAILURE);
1089     }
1090
1091     if (fork_process) {
1092         dup2(old_stderr, STDERR_FILENO);
1093         close(old_stderr);
1094     }
1095
1096     state = RUNNING;
1097     do {
1098         main_loop_wait(false);
1099         if (state == TERMINATE) {
1100             blk_exp_close_all();
1101             state = TERMINATED;
1102         }
1103     } while (state != TERMINATED);
1104
1105     blk_unref(blk);
1106     if (sockpath) {
1107         unlink(sockpath);
1108     }
1109
1110     qemu_opts_del(sn_opts);
1111
1112     if (device) {
1113         void *ret;
1114         pthread_join(client_thread, &ret);
1115         exit(ret != NULL);
1116     } else {
1117         exit(EXIT_SUCCESS);
1118     }
1119 }