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 CONFIG_SELINUX
  51 #include <selinux/selinux.h>
  52 #endif
  53
  54 #ifdef __linux__
  55 #define HAVE_NBD_DEVICE 1
  56 #else
  57 #define HAVE_NBD_DEVICE 0
  58 #endif
  59
  60 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  61 #define QEMU_NBD_OPT_CACHE         256
  62 #define QEMU_NBD_OPT_AIO           257
  63 #define QEMU_NBD_OPT_DISCARD       258
  64 #define QEMU_NBD_OPT_DETECT_ZEROES 259
  65 #define QEMU_NBD_OPT_OBJECT        260
  66 #define QEMU_NBD_OPT_TLSCREDS      261
  67 #define QEMU_NBD_OPT_IMAGE_OPTS    262
  68 #define QEMU_NBD_OPT_FORK          263
  69 #define QEMU_NBD_OPT_TLSAUTHZ      264
  70 #define QEMU_NBD_OPT_PID_FILE      265
  71 #define QEMU_NBD_OPT_SELINUX_LABEL 266
  72
  73 #define MBR_SIZE 512
  74
  75 static int verbose;
  76 static char *srcpath;
  77 static SocketAddress *saddr;
  78 static int persistent = 0;
  79 static enum { RUNNING, TERMINATE, TERMINATED } state;
  80 static int shared = 1;
  81 static int nb_fds;
  82 static QIONetListener *server;
  83 static QCryptoTLSCreds *tlscreds;
  84 static const char *tlsauthz;
  85
  86 static void usage(const char *name)
  87 {
  88     (printf) (
  89 "Usage: %s [OPTIONS] FILE\n"
  90 "  or:  %s -L [OPTIONS]\n"
  91 "QEMU Disk Network Block Device Utility\n"
  92 "\n"
  93 "  -h, --help                display this help and exit\n"
  94 "  -V, --version             output version information and exit\n"
  95 "\n"
  96 "Connection properties:\n"
  97 "  -p, --port=PORT           port to listen on (default `%d')\n"
  98 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  99 "  -k, --socket=PATH         path to the unix socket\n"
 100 "                            (default '"SOCKET_PATH"')\n"
 101 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
 102 "  -t, --persistent          don't exit on the last connection\n"
 103 "  -v, --verbose             display extra debugging information\n"
 104 "  -x, --export-name=NAME    expose export by name (default is empty string)\n"
 105 "  -D, --description=TEXT    export a human-readable description\n"
 106 "\n"
 107 "Exposing part of the image:\n"
 108 "  -o, --offset=OFFSET       offset into the image\n"
 109 "  -A, --allocation-depth    expose the allocation depth\n"
 110 "  -B, --bitmap=NAME         expose a persistent dirty bitmap\n"
 111 "\n"
 112 "General purpose options:\n"
 113 "  -L, --list                list exports available from another NBD server\n"
 114 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
 115 "                            passwords and/or encryption keys\n"
 116 "  --tls-creds=ID            use id of an earlier --object to provide TLS\n"
 117 "  --tls-authz=ID            use id of an earlier --object to provide\n"
 118 "                            authorization\n"
 119 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
 120 "                            specify tracing options\n"
 121 "  --fork                    fork off the server process and exit the parent\n"
 122 "                            once the server is running\n"
 123 "  --pid-file=PATH           store the server's process ID in the given file\n"
 124 #ifdef CONFIG_SELINUX
 125 "  --selinux-label=LABEL     set SELinux process label on listening socket\n"
 126 #endif
 127 #if HAVE_NBD_DEVICE
 128 "\n"
 129 "Kernel NBD client support:\n"
 130 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
 131 "  -d, --disconnect          disconnect the specified device\n"
 132 #endif
 133 "\n"
 134 "Block device options:\n"
 135 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
 136 "  -r, --read-only           export read-only\n"
 137 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
 138 "                            file with backing_file=FILE, redirect the write to\n"
 139 "                            the temporary one\n"
 140 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 141 "                            load an internal snapshot inside FILE and export it\n"
 142 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
 143 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 144 "                            '[ID_OR_NAME]'\n"
 145 "  -n, --nocache             disable host cache\n"
 146 "      --cache=MODE          set cache mode used to access the disk image, the\n"
 147 "                            valid options are: 'none', 'writeback' (default),\n"
 148 "                            'writethrough', 'directsync' and 'unsafe'\n"
 149 "      --aio=MODE            set AIO mode (native, io_uring or threads)\n"
 150 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 151 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 152 "      --image-opts          treat FILE as a full set of image options\n"
 153 "\n"
 154 QEMU_HELP_BOTTOM "\n"
 155     , name, name, NBD_DEFAULT_PORT, "DEVICE");
 156 }
 157
 158 static void version(const char *name)
 159 {
 160     printf(
 161 "%s " QEMU_FULL_VERSION "\n"
 162 "Written by Anthony Liguori.\n"
 163 "\n"
 164 QEMU_COPYRIGHT "\n"
 165 "This is free software; see the source for copying conditions.  There is NO\n"
 166 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 167     , name);
 168 }
 169
 170 #ifdef CONFIG_POSIX
 171 /*
 172  * The client thread uses SIGTERM to interrupt the server.  A signal
 173  * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 174  */
 175 void qemu_system_killed(int signum, pid_t pid)
 176 {
 177     qatomic_cmpxchg(&state, RUNNING, TERMINATE);
 178     qemu_notify_event();
 179 }
 180 #endif /* CONFIG_POSIX */
 181
 182 static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
 183                                 const char *hostname)
 184 {
 185     int ret = EXIT_FAILURE;
 186     int rc;
 187     Error *err = NULL;
 188     QIOChannelSocket *sioc;
 189     NBDExportInfo *list;
 190     int i, j;
 191
 192     sioc = qio_channel_socket_new();
 193     if (qio_channel_socket_connect_sync(sioc, saddr, &err) < 0) {
 194         error_report_err(err);
 195         goto out;
 196     }
 197     rc = nbd_receive_export_list(QIO_CHANNEL(sioc), tls, hostname, &list,
 198                                  &err);
 199     if (rc < 0) {
 200         if (err) {
 201             error_report_err(err);
 202         }
 203         goto out;
 204     }
 205     printf("exports available: %d\n", rc);
 206     for (i = 0; i < rc; i++) {
 207         printf(" export: '%s'\n", list[i].name);
 208         if (list[i].description && *list[i].description) {
 209             printf("  description: %s\n", list[i].description);
 210         }
 211         if (list[i].flags & NBD_FLAG_HAS_FLAGS) {
 212             static const char *const flag_names[] = {
 213                 [NBD_FLAG_READ_ONLY_BIT]            = "readonly",
 214                 [NBD_FLAG_SEND_FLUSH_BIT]           = "flush",
 215                 [NBD_FLAG_SEND_FUA_BIT]             = "fua",
 216                 [NBD_FLAG_ROTATIONAL_BIT]           = "rotational",
 217                 [NBD_FLAG_SEND_TRIM_BIT]            = "trim",
 218                 [NBD_FLAG_SEND_WRITE_ZEROES_BIT]    = "zeroes",
 219                 [NBD_FLAG_SEND_DF_BIT]              = "df",
 220                 [NBD_FLAG_CAN_MULTI_CONN_BIT]       = "multi",
 221                 [NBD_FLAG_SEND_RESIZE_BIT]          = "resize",
 222                 [NBD_FLAG_SEND_CACHE_BIT]           = "cache",
 223                 [NBD_FLAG_SEND_FAST_ZERO_BIT]       = "fast-zero",
 224             };
 225
 226             printf("  size:  %" PRIu64 "\n", list[i].size);
 227             printf("  flags: 0x%x (", list[i].flags);
 228             for (size_t bit = 0; bit < ARRAY_SIZE(flag_names); bit++) {
 229                 if (flag_names[bit] && (list[i].flags & (1 << bit))) {
 230                     printf(" %s", flag_names[bit]);
 231                 }
 232             }
 233             printf(" )\n");
 234         }
 235         if (list[i].min_block) {
 236             printf("  min block: %u\n", list[i].min_block);
 237             printf("  opt block: %u\n", list[i].opt_block);
 238             printf("  max block: %u\n", list[i].max_block);
 239         }
 240         if (list[i].n_contexts) {
 241             printf("  available meta contexts: %d\n", list[i].n_contexts);
 242             for (j = 0; j < list[i].n_contexts; j++) {
 243                 printf("   %s\n", list[i].contexts[j]);
 244             }
 245         }
 246     }
 247     nbd_free_export_list(list, rc);
 248
 249     ret = EXIT_SUCCESS;
 250  out:
 251     object_unref(OBJECT(sioc));
 252     return ret;
 253 }
 254
 255
 256 #if HAVE_NBD_DEVICE
 257 static void *show_parts(void *arg)
 258 {
 259     char *device = arg;
 260     int nbd;
 261
 262     /* linux just needs an open() to trigger
 263      * the partition table update
 264      * but remember to load the module with max_part != 0 :
 265      *     modprobe nbd max_part=63
 266      */
 267     nbd = open(device, O_RDWR);
 268     if (nbd >= 0) {
 269         close(nbd);
 270     }
 271     return NULL;
 272 }
 273
 274 static void *nbd_client_thread(void *arg)
 275 {
 276     char *device = arg;
 277     NBDExportInfo info = { .request_sizes = false, .name = g_strdup("") };
 278     QIOChannelSocket *sioc;
 279     int fd = -1;
 280     int ret = EXIT_FAILURE;
 281     pthread_t show_parts_thread;
 282     Error *local_error = NULL;
 283
 284     sioc = qio_channel_socket_new();
 285     if (qio_channel_socket_connect_sync(sioc,
 286                                         saddr,
 287                                         &local_error) < 0) {
 288         error_report_err(local_error);
 289         goto out;
 290     }
 291
 292     if (nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
 293                               NULL, NULL, NULL, &info, &local_error) < 0) {
 294         if (local_error) {
 295             error_report_err(local_error);
 296         }
 297         goto out;
 298     }
 299
 300     fd = open(device, O_RDWR);
 301     if (fd < 0) {
 302         /* Linux-only, we can use %m in printf.  */
 303         error_report("Failed to open %s: %m", device);
 304         goto out;
 305     }
 306
 307     if (nbd_init(fd, sioc, &info, &local_error) < 0) {
 308         error_report_err(local_error);
 309         goto out;
 310     }
 311
 312     /* update partition table */
 313     pthread_create(&show_parts_thread, NULL, show_parts, device);
 314
 315     if (verbose) {
 316         fprintf(stderr, "NBD device %s is now connected to %s\n",
 317                 device, srcpath);
 318     } else {
 319         /* Close stderr so that the qemu-nbd process exits.  */
 320         dup2(STDOUT_FILENO, STDERR_FILENO);
 321     }
 322
 323     if (nbd_client(fd) < 0) {
 324         goto out;
 325     }
 326
 327     ret = EXIT_SUCCESS;
 328
 329  out:
 330     if (fd >= 0) {
 331         close(fd);
 332     }
 333     object_unref(OBJECT(sioc));
 334     g_free(info.name);
 335     kill(getpid(), SIGTERM);
 336     return (void *) (intptr_t) ret;
 337 }
 338 #endif /* HAVE_NBD_DEVICE */
 339
 340 static int nbd_can_accept(void)
 341 {
 342     return state == RUNNING && (shared == 0 || nb_fds < shared);
 343 }
 344
 345 static void nbd_update_server_watch(void);
 346
 347 static void nbd_client_closed(NBDClient *client, bool negotiated)
 348 {
 349     nb_fds--;
 350     if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
 351         state = TERMINATE;
 352     }
 353     nbd_update_server_watch();
 354     nbd_client_put(client);
 355 }
 356
 357 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
 358                        gpointer opaque)
 359 {
 360     if (state >= TERMINATE) {
 361         return;
 362     }
 363
 364     nb_fds++;
 365     nbd_update_server_watch();
 366     nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
 367 }
 368
 369 static void nbd_update_server_watch(void)
 370 {
 371     if (nbd_can_accept()) {
 372         qio_net_listener_set_client_func(server, nbd_accept, NULL, NULL);
 373     } else {
 374         qio_net_listener_set_client_func(server, NULL, NULL, NULL);
 375     }
 376 }
 377
 378
 379 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 380                                                const char *bindto,
 381                                                const char *port)
 382 {
 383     SocketAddress *saddr;
 384
 385     saddr = g_new0(SocketAddress, 1);
 386     if (sockpath) {
 387         saddr->type = SOCKET_ADDRESS_TYPE_UNIX;
 388         saddr->u.q_unix.path = g_strdup(sockpath);
 389     } else {
 390         InetSocketAddress *inet;
 391         saddr->type = SOCKET_ADDRESS_TYPE_INET;
 392         inet = &saddr->u.inet;
 393         inet->host = g_strdup(bindto);
 394         if (port) {
 395             inet->port = g_strdup(port);
 396         } else  {
 397             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 398         }
 399     }
 400
 401     return saddr;
 402 }
 403
 404
 405 static QemuOptsList file_opts = {
 406     .name = "file",
 407     .implied_opt_name = "file",
 408     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 409     .desc = {
 410         /* no elements => accept any params */
 411         { /* end of list */ }
 412     },
 413 };
 414
 415 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list,
 416                                           Error **errp)
 417 {
 418     Object *obj;
 419     QCryptoTLSCreds *creds;
 420
 421     obj = object_resolve_path_component(
 422         object_get_objects_root(), id);
 423     if (!obj) {
 424         error_setg(errp, "No TLS credentials with id '%s'",
 425                    id);
 426         return NULL;
 427     }
 428     creds = (QCryptoTLSCreds *)
 429         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 430     if (!creds) {
 431         error_setg(errp, "Object with id '%s' is not TLS credentials",
 432                    id);
 433         return NULL;
 434     }
 435
 436     if (!qcrypto_tls_creds_check_endpoint(creds,
 437                                           list
 438                                           ? QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT
 439                                           : QCRYPTO_TLS_CREDS_ENDPOINT_SERVER,
 440                                           errp)) {
 441         return NULL;
 442     }
 443     object_ref(obj);
 444     return creds;
 445 }
 446
 447 static void setup_address_and_port(const char **address, const char **port)
 448 {
 449     if (*address == NULL) {
 450         *address = "0.0.0.0";
 451     }
 452
 453     if (*port == NULL) {
 454         *port = stringify(NBD_DEFAULT_PORT);
 455     }
 456 }
 457
 458 /*
 459  * Check socket parameters compatibility when socket activation is used.
 460  */
 461 static const char *socket_activation_validate_opts(const char *device,
 462                                                    const char *sockpath,
 463                                                    const char *address,
 464                                                    const char *port,
 465                                                    const char *selinux,
 466                                                    bool list)
 467 {
 468     if (device != NULL) {
 469         return "NBD device can't be set when using socket activation";
 470     }
 471
 472     if (sockpath != NULL) {
 473         return "Unix socket can't be set when using socket activation";
 474     }
 475
 476     if (address != NULL) {
 477         return "The interface can't be set when using socket activation";
 478     }
 479
 480     if (port != NULL) {
 481         return "TCP port number can't be set when using socket activation";
 482     }
 483
 484     if (selinux != NULL) {
 485         return "SELinux label can't be set when using socket activation";
 486     }
 487
 488     if (list) {
 489         return "List mode is incompatible with socket activation";
 490     }
 491
 492     return NULL;
 493 }
 494
 495 static void qemu_nbd_shutdown(void)
 496 {
 497     job_cancel_sync_all();
 498     blk_exp_close_all();
 499     bdrv_close_all();
 500 }
 501
 502 int main(int argc, char **argv)
 503 {
 504     BlockBackend *blk;
 505     BlockDriverState *bs;
 506     uint64_t dev_offset = 0;
 507     bool readonly = false;
 508     bool disconnect = false;
 509     const char *bindto = NULL;
 510     const char *port = NULL;
 511     char *sockpath = NULL;
 512     char *device = NULL;
 513     QemuOpts *sn_opts = NULL;
 514     const char *sn_id_or_name = NULL;
 515     const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:AB:L";
 516     struct option lopt[] = {
 517         { "help", no_argument, NULL, 'h' },
 518         { "version", no_argument, NULL, 'V' },
 519         { "bind", required_argument, NULL, 'b' },
 520         { "port", required_argument, NULL, 'p' },
 521         { "socket", required_argument, NULL, 'k' },
 522         { "offset", required_argument, NULL, 'o' },
 523         { "read-only", no_argument, NULL, 'r' },
 524         { "allocation-depth", no_argument, NULL, 'A' },
 525         { "bitmap", required_argument, NULL, 'B' },
 526         { "connect", required_argument, NULL, 'c' },
 527         { "disconnect", no_argument, NULL, 'd' },
 528         { "list", no_argument, NULL, 'L' },
 529         { "snapshot", no_argument, NULL, 's' },
 530         { "load-snapshot", required_argument, NULL, 'l' },
 531         { "nocache", no_argument, NULL, 'n' },
 532         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 533         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 534         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 535         { "detect-zeroes", required_argument, NULL,
 536           QEMU_NBD_OPT_DETECT_ZEROES },
 537         { "shared", required_argument, NULL, 'e' },
 538         { "format", required_argument, NULL, 'f' },
 539         { "persistent", no_argument, NULL, 't' },
 540         { "verbose", no_argument, NULL, 'v' },
 541         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 542         { "export-name", required_argument, NULL, 'x' },
 543         { "description", required_argument, NULL, 'D' },
 544         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 545         { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
 546         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 547         { "trace", required_argument, NULL, 'T' },
 548         { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
 549         { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE },
 550         { "selinux-label", required_argument, NULL,
 551           QEMU_NBD_OPT_SELINUX_LABEL },
 552         { NULL, 0, NULL, 0 }
 553     };
 554     int ch;
 555     int opt_ind = 0;
 556     int flags = BDRV_O_RDWR;
 557     int ret = 0;
 558     bool seen_cache = false;
 559     bool seen_discard = false;
 560     bool seen_aio = false;
 561     pthread_t client_thread;
 562     const char *fmt = NULL;
 563     Error *local_err = NULL;
 564     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 565     QDict *options = NULL;
 566     const char *export_name = NULL; /* defaults to "" later for server mode */
 567     const char *export_description = NULL;
 568     strList *bitmaps = NULL;
 569     bool alloc_depth = false;
 570     const char *tlscredsid = NULL;
 571     bool imageOpts = false;
 572     bool writethrough = false; /* Client will flush as needed. */
 573     bool fork_process = false;
 574     bool list = false;
 575     int old_stderr = -1;
 576     unsigned socket_activation;
 577     const char *pid_file_name = NULL;
 578     const char *selinux_label = NULL;
 579     BlockExportOptions *export_opts;
 580
 581 #ifdef CONFIG_POSIX
 582     os_setup_early_signal_handling();
 583     os_setup_signal_handling();
 584 #endif
 585
 586     socket_init();
 587     error_init(argv[0]);
 588     module_call_init(MODULE_INIT_TRACE);
 589     qcrypto_init(&error_fatal);
 590
 591     module_call_init(MODULE_INIT_QOM);
 592     qemu_add_opts(&qemu_trace_opts);
 593     qemu_init_exec_dir(argv[0]);
 594
 595     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 596         switch (ch) {
 597         case 's':
 598             flags |= BDRV_O_SNAPSHOT;
 599             break;
 600         case 'n':
 601             optarg = (char *) "none";
 602             /* fallthrough */
 603         case QEMU_NBD_OPT_CACHE:
 604             if (seen_cache) {
 605                 error_report("-n and --cache can only be specified once");
 606                 exit(EXIT_FAILURE);
 607             }
 608             seen_cache = true;
 609             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 610                 error_report("Invalid cache mode `%s'", optarg);
 611                 exit(EXIT_FAILURE);
 612             }
 613             break;
 614         case QEMU_NBD_OPT_AIO:
 615             if (seen_aio) {
 616                 error_report("--aio can only be specified once");
 617                 exit(EXIT_FAILURE);
 618             }
 619             seen_aio = true;
 620             if (bdrv_parse_aio(optarg, &flags) < 0) {
 621                 error_report("Invalid aio mode '%s'", optarg);
 622                 exit(EXIT_FAILURE);
 623             }
 624             break;
 625         case QEMU_NBD_OPT_DISCARD:
 626             if (seen_discard) {
 627                 error_report("--discard can only be specified once");
 628                 exit(EXIT_FAILURE);
 629             }
 630             seen_discard = true;
 631             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 632                 error_report("Invalid discard mode `%s'", optarg);
 633                 exit(EXIT_FAILURE);
 634             }
 635             break;
 636         case QEMU_NBD_OPT_DETECT_ZEROES:
 637             detect_zeroes =
 638                 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
 639                                 optarg,
 640                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 641                                 &local_err);
 642             if (local_err) {
 643                 error_reportf_err(local_err,
 644                                   "Failed to parse detect_zeroes mode: ");
 645                 exit(EXIT_FAILURE);
 646             }
 647             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 648                 !(flags & BDRV_O_UNMAP)) {
 649                 error_report("setting detect-zeroes to unmap is not allowed "
 650                              "without setting discard operation to unmap");
 651                 exit(EXIT_FAILURE);
 652             }
 653             break;
 654         case 'b':
 655             bindto = optarg;
 656             break;
 657         case 'p':
 658             port = optarg;
 659             break;
 660         case 'o':
 661             if (qemu_strtou64(optarg, NULL, 0, &dev_offset) < 0) {
 662                 error_report("Invalid offset '%s'", optarg);
 663                 exit(EXIT_FAILURE);
 664             }
 665             break;
 666         case 'l':
 667             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 668                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 669                                                   optarg, false);
 670                 if (!sn_opts) {
 671                     error_report("Failed in parsing snapshot param `%s'",
 672                                  optarg);
 673                     exit(EXIT_FAILURE);
 674                 }
 675             } else {
 676                 sn_id_or_name = optarg;
 677             }
 678             /* fall through */
 679         case 'r':
 680             readonly = true;
 681             flags &= ~BDRV_O_RDWR;
 682             break;
 683         case 'A':
 684             alloc_depth = true;
 685             break;
 686         case 'B':
 687             QAPI_LIST_PREPEND(bitmaps, g_strdup(optarg));
 688             break;
 689         case 'k':
 690             sockpath = optarg;
 691             if (sockpath[0] != '/') {
 692                 error_report("socket path must be absolute");
 693                 exit(EXIT_FAILURE);
 694             }
 695             break;
 696         case 'd':
 697             disconnect = true;
 698             break;
 699         case 'c':
 700             device = optarg;
 701             break;
 702         case 'e':
 703             if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
 704                 shared < 0) {
 705                 error_report("Invalid shared device number '%s'", optarg);
 706                 exit(EXIT_FAILURE);
 707             }
 708             break;
 709         case 'f':
 710             fmt = optarg;
 711             break;
 712         case 't':
 713             persistent = 1;
 714             break;
 715         case 'x':
 716             export_name = optarg;
 717             if (strlen(export_name) > NBD_MAX_STRING_SIZE) {
 718                 error_report("export name '%s' too long", export_name);
 719                 exit(EXIT_FAILURE);
 720             }
 721             break;
 722         case 'D':
 723             export_description = optarg;
 724             if (strlen(export_description) > NBD_MAX_STRING_SIZE) {
 725                 error_report("export description '%s' too long",
 726                              export_description);
 727                 exit(EXIT_FAILURE);
 728             }
 729             break;
 730         case 'v':
 731             verbose = 1;
 732             break;
 733         case 'V':
 734             version(argv[0]);
 735             exit(0);
 736             break;
 737         case 'h':
 738             usage(argv[0]);
 739             exit(0);
 740             break;
 741         case '?':
 742             error_report("Try `%s --help' for more information.", argv[0]);
 743             exit(EXIT_FAILURE);
 744         case QEMU_NBD_OPT_OBJECT:
 745             user_creatable_process_cmdline(optarg);
 746             break;
 747         case QEMU_NBD_OPT_TLSCREDS:
 748             tlscredsid = optarg;
 749             break;
 750         case QEMU_NBD_OPT_IMAGE_OPTS:
 751             imageOpts = true;
 752             break;
 753         case 'T':
 754             trace_opt_parse(optarg);
 755             break;
 756         case QEMU_NBD_OPT_TLSAUTHZ:
 757             tlsauthz = optarg;
 758             break;
 759         case QEMU_NBD_OPT_FORK:
 760             fork_process = true;
 761             break;
 762         case 'L':
 763             list = true;
 764             break;
 765         case QEMU_NBD_OPT_PID_FILE:
 766             pid_file_name = optarg;
 767             break;
 768         case QEMU_NBD_OPT_SELINUX_LABEL:
 769             selinux_label = optarg;
 770             break;
 771         }
 772     }
 773
 774     if (list) {
 775         if (argc != optind) {
 776             error_report("List mode is incompatible with a file name");
 777             exit(EXIT_FAILURE);
 778         }
 779         if (export_name || export_description || dev_offset ||
 780             device || disconnect || fmt || sn_id_or_name || bitmaps ||
 781             alloc_depth || seen_aio || seen_discard || seen_cache) {
 782             error_report("List mode is incompatible with per-device settings");
 783             exit(EXIT_FAILURE);
 784         }
 785         if (fork_process) {
 786             error_report("List mode is incompatible with forking");
 787             exit(EXIT_FAILURE);
 788         }
 789     } else if ((argc - optind) != 1) {
 790         error_report("Invalid number of arguments");
 791         error_printf("Try `%s --help' for more information.\n", argv[0]);
 792         exit(EXIT_FAILURE);
 793     } else if (!export_name) {
 794         export_name = "";
 795     }
 796
 797     if (!trace_init_backends()) {
 798         exit(1);
 799     }
 800     trace_init_file();
 801     qemu_set_log(LOG_TRACE);
 802
 803     socket_activation = check_socket_activation();
 804     if (socket_activation == 0) {
 805         setup_address_and_port(&bindto, &port);
 806     } else {
 807         /* Using socket activation - check user didn't use -p etc. */
 808         const char *err_msg = socket_activation_validate_opts(device, sockpath,
 809                                                               bindto, port,
 810                                                               selinux_label,
 811                                                               list);
 812         if (err_msg != NULL) {
 813             error_report("%s", err_msg);
 814             exit(EXIT_FAILURE);
 815         }
 816
 817         /* qemu-nbd can only listen on a single socket.  */
 818         if (socket_activation > 1) {
 819             error_report("qemu-nbd does not support socket activation with %s > 1",
 820                          "LISTEN_FDS");
 821             exit(EXIT_FAILURE);
 822         }
 823     }
 824
 825     if (tlscredsid) {
 826         if (sockpath) {
 827             error_report("TLS is only supported with IPv4/IPv6");
 828             exit(EXIT_FAILURE);
 829         }
 830         if (device) {
 831             error_report("TLS is not supported with a host device");
 832             exit(EXIT_FAILURE);
 833         }
 834         if (tlsauthz && list) {
 835             error_report("TLS authorization is incompatible with export list");
 836             exit(EXIT_FAILURE);
 837         }
 838         tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
 839         if (local_err) {
 840             error_reportf_err(local_err, "Failed to get TLS creds: ");
 841             exit(EXIT_FAILURE);
 842         }
 843     } else {
 844         if (tlsauthz) {
 845             error_report("--tls-authz is not permitted without --tls-creds");
 846             exit(EXIT_FAILURE);
 847         }
 848     }
 849
 850     if (selinux_label) {
 851 #ifdef CONFIG_SELINUX
 852         if (sockpath == NULL && device == NULL) {
 853             error_report("--selinux-label is not permitted without --socket");
 854             exit(EXIT_FAILURE);
 855         }
 856 #else
 857         error_report("SELinux support not enabled in this binary");
 858         exit(EXIT_FAILURE);
 859 #endif
 860     }
 861
 862     if (list) {
 863         saddr = nbd_build_socket_address(sockpath, bindto, port);
 864         return qemu_nbd_client_list(saddr, tlscreds, bindto);
 865     }
 866
 867 #if !HAVE_NBD_DEVICE
 868     if (disconnect || device) {
 869         error_report("Kernel /dev/nbdN support not available");
 870         exit(EXIT_FAILURE);
 871     }
 872 #else /* HAVE_NBD_DEVICE */
 873     if (disconnect) {
 874         int nbdfd = open(argv[optind], O_RDWR);
 875         if (nbdfd < 0) {
 876             error_report("Cannot open %s: %s", argv[optind],
 877                          strerror(errno));
 878             exit(EXIT_FAILURE);
 879         }
 880         nbd_disconnect(nbdfd);
 881
 882         close(nbdfd);
 883
 884         printf("%s disconnected\n", argv[optind]);
 885
 886         return 0;
 887     }
 888 #endif
 889
 890     if ((device && !verbose) || fork_process) {
 891 #ifndef WIN32
 892         int stderr_fd[2];
 893         pid_t pid;
 894         int ret;
 895
 896         if (qemu_pipe(stderr_fd) < 0) {
 897             error_report("Error setting up communication pipe: %s",
 898                          strerror(errno));
 899             exit(EXIT_FAILURE);
 900         }
 901
 902         /* Now daemonize, but keep a communication channel open to
 903          * print errors and exit with the proper status code.
 904          */
 905         pid = fork();
 906         if (pid < 0) {
 907             error_report("Failed to fork: %s", strerror(errno));
 908             exit(EXIT_FAILURE);
 909         } else if (pid == 0) {
 910             close(stderr_fd[0]);
 911
 912             /* Remember parent's stderr if we will be restoring it. */
 913             if (fork_process) {
 914                 old_stderr = dup(STDERR_FILENO);
 915             }
 916
 917             ret = qemu_daemon(1, 0);
 918
 919             /* Temporarily redirect stderr to the parent's pipe...  */
 920             dup2(stderr_fd[1], STDERR_FILENO);
 921             if (ret < 0) {
 922                 error_report("Failed to daemonize: %s", strerror(errno));
 923                 exit(EXIT_FAILURE);
 924             }
 925
 926             /* ... close the descriptor we inherited and go on.  */
 927             close(stderr_fd[1]);
 928         } else {
 929             bool errors = false;
 930             char *buf;
 931
 932             /* In the parent.  Print error messages from the child until
 933              * it closes the pipe.
 934              */
 935             close(stderr_fd[1]);
 936             buf = g_malloc(1024);
 937             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 938                 errors = true;
 939                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 940                 if (ret < 0) {
 941                     exit(EXIT_FAILURE);
 942                 }
 943             }
 944             if (ret < 0) {
 945                 error_report("Cannot read from daemon: %s",
 946                              strerror(errno));
 947                 exit(EXIT_FAILURE);
 948             }
 949
 950             /* Usually the daemon should not print any message.
 951              * Exit with zero status in that case.
 952              */
 953             exit(errors);
 954         }
 955 #else /* WIN32 */
 956         error_report("Unable to fork into background on Windows hosts");
 957         exit(EXIT_FAILURE);
 958 #endif /* WIN32 */
 959     }
 960
 961     if (device != NULL && sockpath == NULL) {
 962         sockpath = g_malloc(128);
 963         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 964     }
 965
 966     server = qio_net_listener_new();
 967     if (socket_activation == 0) {
 968         int backlog;
 969
 970         if (persistent || shared == 0) {
 971             backlog = SOMAXCONN;
 972         } else {
 973             backlog = MIN(shared, SOMAXCONN);
 974         }
 975 #ifdef CONFIG_SELINUX
 976         if (selinux_label && setsockcreatecon_raw(selinux_label) == -1) {
 977             error_report("Cannot set SELinux socket create context to %s: %s",
 978                          selinux_label, strerror(errno));
 979             exit(EXIT_FAILURE);
 980         }
 981 #endif
 982         saddr = nbd_build_socket_address(sockpath, bindto, port);
 983         if (qio_net_listener_open_sync(server, saddr, backlog,
 984                                        &local_err) < 0) {
 985             object_unref(OBJECT(server));
 986             error_report_err(local_err);
 987             exit(EXIT_FAILURE);
 988         }
 989 #ifdef CONFIG_SELINUX
 990         if (selinux_label && setsockcreatecon_raw(NULL) == -1) {
 991             error_report("Cannot clear SELinux socket create context: %s",
 992                          strerror(errno));
 993             exit(EXIT_FAILURE);
 994         }
 995 #endif
 996     } else {
 997         size_t i;
 998         /* See comment in check_socket_activation above. */
 999         for (i = 0; i < socket_activation; i++) {
1000             QIOChannelSocket *sioc;
1001             sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
1002                                              &local_err);
1003             if (sioc == NULL) {
1004                 object_unref(OBJECT(server));
1005                 error_reportf_err(local_err,
1006                                   "Failed to use socket activation: ");
1007                 exit(EXIT_FAILURE);
1008             }
1009             qio_net_listener_add(server, sioc);
1010             object_unref(OBJECT(sioc));
1011         }
1012     }
1013
1014     qemu_init_main_loop(&error_fatal);
1015     bdrv_init();
1016     atexit(qemu_nbd_shutdown);
1017
1018     srcpath = argv[optind];
1019     if (imageOpts) {
1020         QemuOpts *opts;
1021         if (fmt) {
1022             error_report("--image-opts and -f are mutually exclusive");
1023             exit(EXIT_FAILURE);
1024         }
1025         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
1026         if (!opts) {
1027             qemu_opts_reset(&file_opts);
1028             exit(EXIT_FAILURE);
1029         }
1030         options = qemu_opts_to_qdict(opts, NULL);
1031         qemu_opts_reset(&file_opts);
1032         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
1033     } else {
1034         if (fmt) {
1035             options = qdict_new();
1036             qdict_put_str(options, "driver", fmt);
1037         }
1038         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
1039     }
1040
1041     if (!blk) {
1042         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
1043                           argv[optind]);
1044         exit(EXIT_FAILURE);
1045     }
1046     bs = blk_bs(blk);
1047
1048     if (dev_offset) {
1049         QDict *raw_opts = qdict_new();
1050         qdict_put_str(raw_opts, "driver", "raw");
1051         qdict_put_str(raw_opts, "file", bs->node_name);
1052         qdict_put_int(raw_opts, "offset", dev_offset);
1053         bs = bdrv_open(NULL, NULL, raw_opts, flags, &error_fatal);
1054         blk_remove_bs(blk);
1055         blk_insert_bs(blk, bs, &error_fatal);
1056         bdrv_unref(bs);
1057     }
1058
1059     blk_set_enable_write_cache(blk, !writethrough);
1060
1061     if (sn_opts) {
1062         ret = bdrv_snapshot_load_tmp(bs,
1063                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
1064                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
1065                                      &local_err);
1066     } else if (sn_id_or_name) {
1067         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
1068                                                    &local_err);
1069     }
1070     if (ret < 0) {
1071         error_reportf_err(local_err, "Failed to load snapshot: ");
1072         exit(EXIT_FAILURE);
1073     }
1074
1075     bs->detect_zeroes = detect_zeroes;
1076
1077     nbd_server_is_qemu_nbd(true);
1078
1079     export_opts = g_new(BlockExportOptions, 1);
1080     *export_opts = (BlockExportOptions) {
1081         .type               = BLOCK_EXPORT_TYPE_NBD,
1082         .id                 = g_strdup("qemu-nbd-export"),
1083         .node_name          = g_strdup(bdrv_get_node_name(bs)),
1084         .has_writethrough   = true,
1085         .writethrough       = writethrough,
1086         .has_writable       = true,
1087         .writable           = !readonly,
1088         .u.nbd = {
1089             .has_name             = true,
1090             .name                 = g_strdup(export_name),
1091             .has_description      = !!export_description,
1092             .description          = g_strdup(export_description),
1093             .has_bitmaps          = !!bitmaps,
1094             .bitmaps              = bitmaps,
1095             .has_allocation_depth = alloc_depth,
1096             .allocation_depth     = alloc_depth,
1097         },
1098     };
1099     blk_exp_add(export_opts, &error_fatal);
1100     qapi_free_BlockExportOptions(export_opts);
1101
1102     if (device) {
1103 #if HAVE_NBD_DEVICE
1104         int ret;
1105
1106         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1107         if (ret != 0) {
1108             error_report("Failed to create client thread: %s", strerror(ret));
1109             exit(EXIT_FAILURE);
1110         }
1111 #endif
1112     } else {
1113         /* Shut up GCC warnings.  */
1114         memset(&client_thread, 0, sizeof(client_thread));
1115     }
1116
1117     nbd_update_server_watch();
1118
1119     if (pid_file_name) {
1120         qemu_write_pidfile(pid_file_name, &error_fatal);
1121     }
1122
1123     /* now when the initialization is (almost) complete, chdir("/")
1124      * to free any busy filesystems */
1125     if (chdir("/") < 0) {
1126         error_report("Could not chdir to root directory: %s",
1127                      strerror(errno));
1128         exit(EXIT_FAILURE);
1129     }
1130
1131     if (fork_process) {
1132         dup2(old_stderr, STDERR_FILENO);
1133         close(old_stderr);
1134     }
1135
1136     state = RUNNING;
1137     do {
1138         main_loop_wait(false);
1139         if (state == TERMINATE) {
1140             blk_exp_close_all();
1141             state = TERMINATED;
1142         }
1143     } while (state != TERMINATED);
1144
1145     blk_unref(blk);
1146     if (sockpath) {
1147         unlink(sockpath);
1148     }
1149
1150     qemu_opts_del(sn_opts);
1151
1152     if (device) {
1153         void *ret;
1154         pthread_join(client_thread, &ret);
1155         exit(ret != NULL);
1156     } else {
1157         exit(EXIT_SUCCESS);
1158     }
1159 }