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