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/help-texts.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 #define QEMU_NBD_OPT_TLSHOSTNAME   267
  73
  74 #define MBR_SIZE 512
  75
  76 static int verbose;
  77 static char *srcpath;
  78 static SocketAddress *saddr;
  79 static int persistent = 0;
  80 static enum { RUNNING, TERMINATE, TERMINATED } state;
  81 static int shared = 1;
  82 static int nb_fds;
  83 static QIONetListener *server;
  84 static QCryptoTLSCreds *tlscreds;
  85 static const char *tlsauthz;
  86
  87 static void usage(const char *name)
  88 {
  89     (printf) (
  90 "Usage: %s [OPTIONS] FILE\n"
  91 "  or:  %s -L [OPTIONS]\n"
  92 "QEMU Disk Network Block Device Utility\n"
  93 "\n"
  94 "  -h, --help                display this help and exit\n"
  95 "  -V, --version             output version information and exit\n"
  96 "\n"
  97 "Connection properties:\n"
  98 "  -p, --port=PORT           port to listen on (default `%d')\n"
  99 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
 100 "  -k, --socket=PATH         path to the unix socket\n"
 101 "                            (default '"SOCKET_PATH"')\n"
 102 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
 103 "  -t, --persistent          don't exit on the last connection\n"
 104 "  -v, --verbose             display extra debugging information\n"
 105 "  -x, --export-name=NAME    expose export by name (default is empty string)\n"
 106 "  -D, --description=TEXT    export a human-readable description\n"
 107 "\n"
 108 "Exposing part of the image:\n"
 109 "  -o, --offset=OFFSET       offset into the image\n"
 110 "  -A, --allocation-depth    expose the allocation depth\n"
 111 "  -B, --bitmap=NAME         expose a persistent dirty bitmap\n"
 112 "\n"
 113 "General purpose options:\n"
 114 "  -L, --list                list exports available from another NBD server\n"
 115 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
 116 "                            passwords and/or encryption keys\n"
 117 "  --tls-creds=ID            use id of an earlier --object to provide TLS\n"
 118 "  --tls-authz=ID            use id of an earlier --object to provide\n"
 119 "                            authorization\n"
 120 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
 121 "                            specify tracing options\n"
 122 "  --fork                    fork off the server process and exit the parent\n"
 123 "                            once the server is running\n"
 124 "  --pid-file=PATH           store the server's process ID in the given file\n"
 125 #ifdef CONFIG_SELINUX
 126 "  --selinux-label=LABEL     set SELinux process label on listening socket\n"
 127 #endif
 128 #if HAVE_NBD_DEVICE
 129 "\n"
 130 "Kernel NBD client support:\n"
 131 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
 132 "  -d, --disconnect          disconnect the specified device\n"
 133 #endif
 134 "\n"
 135 "Block device options:\n"
 136 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
 137 "  -r, --read-only           export read-only\n"
 138 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
 139 "                            file with backing_file=FILE, redirect the write to\n"
 140 "                            the temporary one\n"
 141 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 142 "                            load an internal snapshot inside FILE and export it\n"
 143 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
 144 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 145 "                            '[ID_OR_NAME]'\n"
 146 "  -n, --nocache             disable host cache\n"
 147 "      --cache=MODE          set cache mode used to access the disk image, the\n"
 148 "                            valid options are: 'none', 'writeback' (default),\n"
 149 "                            'writethrough', 'directsync' and 'unsafe'\n"
 150 "      --aio=MODE            set AIO mode (native, io_uring or threads)\n"
 151 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 152 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 153 "      --image-opts          treat FILE as a full set of image options\n"
 154 "\n"
 155 QEMU_HELP_BOTTOM "\n"
 156     , name, name, NBD_DEFAULT_PORT, "DEVICE");
 157 }
 158
 159 static void version(const char *name)
 160 {
 161     printf(
 162 "%s " QEMU_FULL_VERSION "\n"
 163 "Written by Anthony Liguori.\n"
 164 "\n"
 165 QEMU_COPYRIGHT "\n"
 166 "This is free software; see the source for copying conditions.  There is NO\n"
 167 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 168     , name);
 169 }
 170
 171 #ifdef CONFIG_POSIX
 172 /*
 173  * The client thread uses SIGTERM to interrupt the server.  A signal
 174  * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 175  */
 176 void qemu_system_killed(int signum, pid_t pid)
 177 {
 178     qatomic_cmpxchg(&state, RUNNING, TERMINATE);
 179     qemu_notify_event();
 180 }
 181 #endif /* CONFIG_POSIX */
 182
 183 static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
 184                                 const char *hostname)
 185 {
 186     int ret = EXIT_FAILURE;
 187     int rc;
 188     Error *err = NULL;
 189     QIOChannelSocket *sioc;
 190     NBDExportInfo *list;
 191     int i, j;
 192
 193     sioc = qio_channel_socket_new();
 194     if (qio_channel_socket_connect_sync(sioc, saddr, &err) < 0) {
 195         error_report_err(err);
 196         goto out;
 197     }
 198     rc = nbd_receive_export_list(QIO_CHANNEL(sioc), tls, hostname, &list,
 199                                  &err);
 200     if (rc < 0) {
 201         if (err) {
 202             error_report_err(err);
 203         }
 204         goto out;
 205     }
 206     printf("exports available: %d\n", rc);
 207     for (i = 0; i < rc; i++) {
 208         printf(" export: '%s'\n", list[i].name);
 209         if (list[i].description && *list[i].description) {
 210             printf("  description: %s\n", list[i].description);
 211         }
 212         if (list[i].flags & NBD_FLAG_HAS_FLAGS) {
 213             static const char *const flag_names[] = {
 214                 [NBD_FLAG_READ_ONLY_BIT]            = "readonly",
 215                 [NBD_FLAG_SEND_FLUSH_BIT]           = "flush",
 216                 [NBD_FLAG_SEND_FUA_BIT]             = "fua",
 217                 [NBD_FLAG_ROTATIONAL_BIT]           = "rotational",
 218                 [NBD_FLAG_SEND_TRIM_BIT]            = "trim",
 219                 [NBD_FLAG_SEND_WRITE_ZEROES_BIT]    = "zeroes",
 220                 [NBD_FLAG_SEND_DF_BIT]              = "df",
 221                 [NBD_FLAG_CAN_MULTI_CONN_BIT]       = "multi",
 222                 [NBD_FLAG_SEND_RESIZE_BIT]          = "resize",
 223                 [NBD_FLAG_SEND_CACHE_BIT]           = "cache",
 224                 [NBD_FLAG_SEND_FAST_ZERO_BIT]       = "fast-zero",
 225             };
 226
 227             printf("  size:  %" PRIu64 "\n", list[i].size);
 228             printf("  flags: 0x%x (", list[i].flags);
 229             for (size_t bit = 0; bit < ARRAY_SIZE(flag_names); bit++) {
 230                 if (flag_names[bit] && (list[i].flags & (1 << bit))) {
 231                     printf(" %s", flag_names[bit]);
 232                 }
 233             }
 234             printf(" )\n");
 235         }
 236         if (list[i].min_block) {
 237             printf("  min block: %u\n", list[i].min_block);
 238             printf("  opt block: %u\n", list[i].opt_block);
 239             printf("  max block: %u\n", list[i].max_block);
 240         }
 241         if (list[i].n_contexts) {
 242             printf("  available meta contexts: %d\n", list[i].n_contexts);
 243             for (j = 0; j < list[i].n_contexts; j++) {
 244                 printf("   %s\n", list[i].contexts[j]);
 245             }
 246         }
 247     }
 248     nbd_free_export_list(list, rc);
 249
 250     ret = EXIT_SUCCESS;
 251  out:
 252     object_unref(OBJECT(sioc));
 253     return ret;
 254 }
 255
 256
 257 #if HAVE_NBD_DEVICE
 258 static void *show_parts(void *arg)
 259 {
 260     char *device = arg;
 261     int nbd;
 262
 263     /* linux just needs an open() to trigger
 264      * the partition table update
 265      * but remember to load the module with max_part != 0 :
 266      *     modprobe nbd max_part=63
 267      */
 268     nbd = open(device, O_RDWR);
 269     if (nbd >= 0) {
 270         close(nbd);
 271     }
 272     return NULL;
 273 }
 274
 275 static void *nbd_client_thread(void *arg)
 276 {
 277     char *device = arg;
 278     NBDExportInfo info = { .request_sizes = false, .name = g_strdup("") };
 279     QIOChannelSocket *sioc;
 280     int fd = -1;
 281     int ret = EXIT_FAILURE;
 282     pthread_t show_parts_thread;
 283     Error *local_error = NULL;
 284
 285     sioc = qio_channel_socket_new();
 286     if (qio_channel_socket_connect_sync(sioc,
 287                                         saddr,
 288                                         &local_error) < 0) {
 289         error_report_err(local_error);
 290         goto out;
 291     }
 292
 293     if (nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
 294                               NULL, NULL, NULL, &info, &local_error) < 0) {
 295         if (local_error) {
 296             error_report_err(local_error);
 297         }
 298         goto out;
 299     }
 300
 301     fd = open(device, O_RDWR);
 302     if (fd < 0) {
 303         /* Linux-only, we can use %m in printf.  */
 304         error_report("Failed to open %s: %m", device);
 305         goto out;
 306     }
 307
 308     if (nbd_init(fd, sioc, &info, &local_error) < 0) {
 309         error_report_err(local_error);
 310         goto out;
 311     }
 312
 313     /* update partition table */
 314     pthread_create(&show_parts_thread, NULL, show_parts, device);
 315
 316     if (verbose) {
 317         fprintf(stderr, "NBD device %s is now connected to %s\n",
 318                 device, srcpath);
 319     } else {
 320         /* Close stderr so that the qemu-nbd process exits.  */
 321         dup2(STDOUT_FILENO, STDERR_FILENO);
 322     }
 323
 324     if (nbd_client(fd) < 0) {
 325         goto out;
 326     }
 327
 328     ret = EXIT_SUCCESS;
 329
 330  out:
 331     if (fd >= 0) {
 332         close(fd);
 333     }
 334     object_unref(OBJECT(sioc));
 335     g_free(info.name);
 336     kill(getpid(), SIGTERM);
 337     return (void *) (intptr_t) ret;
 338 }
 339 #endif /* HAVE_NBD_DEVICE */
 340
 341 static int nbd_can_accept(void)
 342 {
 343     return state == RUNNING && (shared == 0 || nb_fds < shared);
 344 }
 345
 346 static void nbd_update_server_watch(void);
 347
 348 static void nbd_client_closed(NBDClient *client, bool negotiated)
 349 {
 350     nb_fds--;
 351     if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
 352         state = TERMINATE;
 353     }
 354     nbd_update_server_watch();
 355     nbd_client_put(client);
 356 }
 357
 358 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
 359                        gpointer opaque)
 360 {
 361     if (state >= TERMINATE) {
 362         return;
 363     }
 364
 365     nb_fds++;
 366     nbd_update_server_watch();
 367     nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
 368 }
 369
 370 static void nbd_update_server_watch(void)
 371 {
 372     if (nbd_can_accept()) {
 373         qio_net_listener_set_client_func(server, nbd_accept, NULL, NULL);
 374     } else {
 375         qio_net_listener_set_client_func(server, NULL, NULL, NULL);
 376     }
 377 }
 378
 379
 380 static SocketAddress *nbd_build_socket_address(const char *sockpath,
 381                                                const char *bindto,
 382                                                const char *port)
 383 {
 384     SocketAddress *saddr;
 385
 386     saddr = g_new0(SocketAddress, 1);
 387     if (sockpath) {
 388         saddr->type = SOCKET_ADDRESS_TYPE_UNIX;
 389         saddr->u.q_unix.path = g_strdup(sockpath);
 390     } else {
 391         InetSocketAddress *inet;
 392         saddr->type = SOCKET_ADDRESS_TYPE_INET;
 393         inet = &saddr->u.inet;
 394         inet->host = g_strdup(bindto);
 395         if (port) {
 396             inet->port = g_strdup(port);
 397         } else  {
 398             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 399         }
 400     }
 401
 402     return saddr;
 403 }
 404
 405
 406 static QemuOptsList file_opts = {
 407     .name = "file",
 408     .implied_opt_name = "file",
 409     .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 410     .desc = {
 411         /* no elements => accept any params */
 412         { /* end of list */ }
 413     },
 414 };
 415
 416 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list,
 417                                           Error **errp)
 418 {
 419     Object *obj;
 420     QCryptoTLSCreds *creds;
 421
 422     obj = object_resolve_path_component(
 423         object_get_objects_root(), id);
 424     if (!obj) {
 425         error_setg(errp, "No TLS credentials with id '%s'",
 426                    id);
 427         return NULL;
 428     }
 429     creds = (QCryptoTLSCreds *)
 430         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 431     if (!creds) {
 432         error_setg(errp, "Object with id '%s' is not TLS credentials",
 433                    id);
 434         return NULL;
 435     }
 436
 437     if (!qcrypto_tls_creds_check_endpoint(creds,
 438                                           list
 439                                           ? QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT
 440                                           : QCRYPTO_TLS_CREDS_ENDPOINT_SERVER,
 441                                           errp)) {
 442         return NULL;
 443     }
 444     object_ref(obj);
 445     return creds;
 446 }
 447
 448 static void setup_address_and_port(const char **address, const char **port)
 449 {
 450     if (*address == NULL) {
 451         *address = "0.0.0.0";
 452     }
 453
 454     if (*port == NULL) {
 455         *port = stringify(NBD_DEFAULT_PORT);
 456     }
 457 }
 458
 459 /*
 460  * Check socket parameters compatibility when socket activation is used.
 461  */
 462 static const char *socket_activation_validate_opts(const char *device,
 463                                                    const char *sockpath,
 464                                                    const char *address,
 465                                                    const char *port,
 466                                                    const char *selinux,
 467                                                    bool list)
 468 {
 469     if (device != NULL) {
 470         return "NBD device can't be set when using socket activation";
 471     }
 472
 473     if (sockpath != NULL) {
 474         return "Unix socket can't be set when using socket activation";
 475     }
 476
 477     if (address != NULL) {
 478         return "The interface can't be set when using socket activation";
 479     }
 480
 481     if (port != NULL) {
 482         return "TCP port number can't be set when using socket activation";
 483     }
 484
 485     if (selinux != NULL) {
 486         return "SELinux label can't be set when using socket activation";
 487     }
 488
 489     if (list) {
 490         return "List mode is incompatible with socket activation";
 491     }
 492
 493     return NULL;
 494 }
 495
 496 static void qemu_nbd_shutdown(void)
 497 {
 498     job_cancel_sync_all();
 499     blk_exp_close_all();
 500     bdrv_close_all();
 501 }
 502
 503 int main(int argc, char **argv)
 504 {
 505     BlockBackend *blk;
 506     BlockDriverState *bs;
 507     uint64_t dev_offset = 0;
 508     bool readonly = false;
 509     bool disconnect = false;
 510     const char *bindto = NULL;
 511     const char *port = NULL;
 512     char *sockpath = NULL;
 513     char *device = NULL;
 514     QemuOpts *sn_opts = NULL;
 515     const char *sn_id_or_name = NULL;
 516     const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:AB:L";
 517     struct option lopt[] = {
 518         { "help", no_argument, NULL, 'h' },
 519         { "version", no_argument, NULL, 'V' },
 520         { "bind", required_argument, NULL, 'b' },
 521         { "port", required_argument, NULL, 'p' },
 522         { "socket", required_argument, NULL, 'k' },
 523         { "offset", required_argument, NULL, 'o' },
 524         { "read-only", no_argument, NULL, 'r' },
 525         { "allocation-depth", no_argument, NULL, 'A' },
 526         { "bitmap", required_argument, NULL, 'B' },
 527         { "connect", required_argument, NULL, 'c' },
 528         { "disconnect", no_argument, NULL, 'd' },
 529         { "list", no_argument, NULL, 'L' },
 530         { "snapshot", no_argument, NULL, 's' },
 531         { "load-snapshot", required_argument, NULL, 'l' },
 532         { "nocache", no_argument, NULL, 'n' },
 533         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 534         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 535         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 536         { "detect-zeroes", required_argument, NULL,
 537           QEMU_NBD_OPT_DETECT_ZEROES },
 538         { "shared", required_argument, NULL, 'e' },
 539         { "format", required_argument, NULL, 'f' },
 540         { "persistent", no_argument, NULL, 't' },
 541         { "verbose", no_argument, NULL, 'v' },
 542         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 543         { "export-name", required_argument, NULL, 'x' },
 544         { "description", required_argument, NULL, 'D' },
 545         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 546         { "tls-hostname", required_argument, NULL, QEMU_NBD_OPT_TLSHOSTNAME },
 547         { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
 548         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 549         { "trace", required_argument, NULL, 'T' },
 550         { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
 551         { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE },
 552         { "selinux-label", required_argument, NULL,
 553           QEMU_NBD_OPT_SELINUX_LABEL },
 554         { NULL, 0, NULL, 0 }
 555     };
 556     int ch;
 557     int opt_ind = 0;
 558     int flags = BDRV_O_RDWR;
 559     int ret = 0;
 560     bool seen_cache = false;
 561     bool seen_discard = false;
 562     bool seen_aio = false;
 563     pthread_t client_thread;
 564     const char *fmt = NULL;
 565     Error *local_err = NULL;
 566     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 567     QDict *options = NULL;
 568     const char *export_name = NULL; /* defaults to "" later for server mode */
 569     const char *export_description = NULL;
 570     strList *bitmaps = NULL;
 571     bool alloc_depth = false;
 572     const char *tlscredsid = NULL;
 573     const char *tlshostname = NULL;
 574     bool imageOpts = false;
 575     bool writethrough = false; /* Client will flush as needed. */
 576     bool fork_process = false;
 577     bool list = false;
 578     int old_stderr = -1;
 579     unsigned socket_activation;
 580     const char *pid_file_name = NULL;
 581     const char *selinux_label = NULL;
 582     BlockExportOptions *export_opts;
 583
 584 #ifdef CONFIG_POSIX
 585     os_setup_early_signal_handling();
 586     os_setup_signal_handling();
 587 #endif
 588
 589     socket_init();
 590     error_init(argv[0]);
 591     module_call_init(MODULE_INIT_TRACE);
 592     qcrypto_init(&error_fatal);
 593
 594     module_call_init(MODULE_INIT_QOM);
 595     qemu_add_opts(&qemu_trace_opts);
 596     qemu_init_exec_dir(argv[0]);
 597
 598     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 599         switch (ch) {
 600         case 's':
 601             flags |= BDRV_O_SNAPSHOT;
 602             break;
 603         case 'n':
 604             optarg = (char *) "none";
 605             /* fallthrough */
 606         case QEMU_NBD_OPT_CACHE:
 607             if (seen_cache) {
 608                 error_report("-n and --cache can only be specified once");
 609                 exit(EXIT_FAILURE);
 610             }
 611             seen_cache = true;
 612             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 613                 error_report("Invalid cache mode `%s'", optarg);
 614                 exit(EXIT_FAILURE);
 615             }
 616             break;
 617         case QEMU_NBD_OPT_AIO:
 618             if (seen_aio) {
 619                 error_report("--aio can only be specified once");
 620                 exit(EXIT_FAILURE);
 621             }
 622             seen_aio = true;
 623             if (bdrv_parse_aio(optarg, &flags) < 0) {
 624                 error_report("Invalid aio mode '%s'", optarg);
 625                 exit(EXIT_FAILURE);
 626             }
 627             break;
 628         case QEMU_NBD_OPT_DISCARD:
 629             if (seen_discard) {
 630                 error_report("--discard can only be specified once");
 631                 exit(EXIT_FAILURE);
 632             }
 633             seen_discard = true;
 634             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 635                 error_report("Invalid discard mode `%s'", optarg);
 636                 exit(EXIT_FAILURE);
 637             }
 638             break;
 639         case QEMU_NBD_OPT_DETECT_ZEROES:
 640             detect_zeroes =
 641                 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
 642                                 optarg,
 643                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 644                                 &local_err);
 645             if (local_err) {
 646                 error_reportf_err(local_err,
 647                                   "Failed to parse detect_zeroes mode: ");
 648                 exit(EXIT_FAILURE);
 649             }
 650             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 651                 !(flags & BDRV_O_UNMAP)) {
 652                 error_report("setting detect-zeroes to unmap is not allowed "
 653                              "without setting discard operation to unmap");
 654                 exit(EXIT_FAILURE);
 655             }
 656             break;
 657         case 'b':
 658             bindto = optarg;
 659             break;
 660         case 'p':
 661             port = optarg;
 662             break;
 663         case 'o':
 664             if (qemu_strtou64(optarg, NULL, 0, &dev_offset) < 0) {
 665                 error_report("Invalid offset '%s'", optarg);
 666                 exit(EXIT_FAILURE);
 667             }
 668             break;
 669         case 'l':
 670             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 671                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 672                                                   optarg, false);
 673                 if (!sn_opts) {
 674                     error_report("Failed in parsing snapshot param `%s'",
 675                                  optarg);
 676                     exit(EXIT_FAILURE);
 677                 }
 678             } else {
 679                 sn_id_or_name = optarg;
 680             }
 681             /* fall through */
 682         case 'r':
 683             readonly = true;
 684             flags &= ~BDRV_O_RDWR;
 685             break;
 686         case 'A':
 687             alloc_depth = true;
 688             break;
 689         case 'B':
 690             QAPI_LIST_PREPEND(bitmaps, g_strdup(optarg));
 691             break;
 692         case 'k':
 693             sockpath = optarg;
 694             if (sockpath[0] != '/') {
 695                 error_report("socket path must be absolute");
 696                 exit(EXIT_FAILURE);
 697             }
 698             break;
 699         case 'd':
 700             disconnect = true;
 701             break;
 702         case 'c':
 703             device = optarg;
 704             break;
 705         case 'e':
 706             if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
 707                 shared < 0) {
 708                 error_report("Invalid shared device number '%s'", optarg);
 709                 exit(EXIT_FAILURE);
 710             }
 711             break;
 712         case 'f':
 713             fmt = optarg;
 714             break;
 715         case 't':
 716             persistent = 1;
 717             break;
 718         case 'x':
 719             export_name = optarg;
 720             if (strlen(export_name) > NBD_MAX_STRING_SIZE) {
 721                 error_report("export name '%s' too long", export_name);
 722                 exit(EXIT_FAILURE);
 723             }
 724             break;
 725         case 'D':
 726             export_description = optarg;
 727             if (strlen(export_description) > NBD_MAX_STRING_SIZE) {
 728                 error_report("export description '%s' too long",
 729                              export_description);
 730                 exit(EXIT_FAILURE);
 731             }
 732             break;
 733         case 'v':
 734             verbose = 1;
 735             break;
 736         case 'V':
 737             version(argv[0]);
 738             exit(0);
 739             break;
 740         case 'h':
 741             usage(argv[0]);
 742             exit(0);
 743             break;
 744         case '?':
 745             error_report("Try `%s --help' for more information.", argv[0]);
 746             exit(EXIT_FAILURE);
 747         case QEMU_NBD_OPT_OBJECT:
 748             user_creatable_process_cmdline(optarg);
 749             break;
 750         case QEMU_NBD_OPT_TLSCREDS:
 751             tlscredsid = optarg;
 752             break;
 753         case QEMU_NBD_OPT_TLSHOSTNAME:
 754             tlshostname = optarg;
 755             break;
 756         case QEMU_NBD_OPT_IMAGE_OPTS:
 757             imageOpts = true;
 758             break;
 759         case 'T':
 760             trace_opt_parse(optarg);
 761             break;
 762         case QEMU_NBD_OPT_TLSAUTHZ:
 763             tlsauthz = optarg;
 764             break;
 765         case QEMU_NBD_OPT_FORK:
 766             fork_process = true;
 767             break;
 768         case 'L':
 769             list = true;
 770             break;
 771         case QEMU_NBD_OPT_PID_FILE:
 772             pid_file_name = optarg;
 773             break;
 774         case QEMU_NBD_OPT_SELINUX_LABEL:
 775             selinux_label = optarg;
 776             break;
 777         }
 778     }
 779
 780     if (list) {
 781         if (argc != optind) {
 782             error_report("List mode is incompatible with a file name");
 783             exit(EXIT_FAILURE);
 784         }
 785         if (export_name || export_description || dev_offset ||
 786             device || disconnect || fmt || sn_id_or_name || bitmaps ||
 787             alloc_depth || seen_aio || seen_discard || seen_cache) {
 788             error_report("List mode is incompatible with per-device settings");
 789             exit(EXIT_FAILURE);
 790         }
 791         if (fork_process) {
 792             error_report("List mode is incompatible with forking");
 793             exit(EXIT_FAILURE);
 794         }
 795     } else if ((argc - optind) != 1) {
 796         error_report("Invalid number of arguments");
 797         error_printf("Try `%s --help' for more information.\n", argv[0]);
 798         exit(EXIT_FAILURE);
 799     } else if (!export_name) {
 800         export_name = "";
 801     }
 802
 803     if (!trace_init_backends()) {
 804         exit(1);
 805     }
 806     trace_init_file();
 807     qemu_set_log(LOG_TRACE, &error_fatal);
 808
 809     socket_activation = check_socket_activation();
 810     if (socket_activation == 0) {
 811         if (!sockpath) {
 812             setup_address_and_port(&bindto, &port);
 813         }
 814     } else {
 815         /* Using socket activation - check user didn't use -p etc. */
 816         const char *err_msg = socket_activation_validate_opts(device, sockpath,
 817                                                               bindto, port,
 818                                                               selinux_label,
 819                                                               list);
 820         if (err_msg != NULL) {
 821             error_report("%s", err_msg);
 822             exit(EXIT_FAILURE);
 823         }
 824
 825         /* qemu-nbd can only listen on a single socket.  */
 826         if (socket_activation > 1) {
 827             error_report("qemu-nbd does not support socket activation with %s > 1",
 828                          "LISTEN_FDS");
 829             exit(EXIT_FAILURE);
 830         }
 831     }
 832
 833     if (tlscredsid) {
 834         if (device) {
 835             error_report("TLS is not supported with a host device");
 836             exit(EXIT_FAILURE);
 837         }
 838         if (tlsauthz && list) {
 839             error_report("TLS authorization is incompatible with export list");
 840             exit(EXIT_FAILURE);
 841         }
 842         if (tlshostname && !list) {
 843             error_report("TLS hostname is only supported with export list");
 844             exit(EXIT_FAILURE);
 845         }
 846         tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
 847         if (local_err) {
 848             error_reportf_err(local_err, "Failed to get TLS creds: ");
 849             exit(EXIT_FAILURE);
 850         }
 851     } else {
 852         if (tlsauthz) {
 853             error_report("--tls-authz is not permitted without --tls-creds");
 854             exit(EXIT_FAILURE);
 855         }
 856         if (tlshostname) {
 857             error_report("--tls-hostname is not permitted without --tls-creds");
 858             exit(EXIT_FAILURE);
 859         }
 860     }
 861
 862     if (selinux_label) {
 863 #ifdef CONFIG_SELINUX
 864         if (sockpath == NULL && device == NULL) {
 865             error_report("--selinux-label is not permitted without --socket");
 866             exit(EXIT_FAILURE);
 867         }
 868 #else
 869         error_report("SELinux support not enabled in this binary");
 870         exit(EXIT_FAILURE);
 871 #endif
 872     }
 873
 874     if (list) {
 875         saddr = nbd_build_socket_address(sockpath, bindto, port);
 876         return qemu_nbd_client_list(saddr, tlscreds,
 877                                     tlshostname ? tlshostname : bindto);
 878     }
 879
 880 #if !HAVE_NBD_DEVICE
 881     if (disconnect || device) {
 882         error_report("Kernel /dev/nbdN support not available");
 883         exit(EXIT_FAILURE);
 884     }
 885 #else /* HAVE_NBD_DEVICE */
 886     if (disconnect) {
 887         int nbdfd = open(argv[optind], O_RDWR);
 888         if (nbdfd < 0) {
 889             error_report("Cannot open %s: %s", argv[optind],
 890                          strerror(errno));
 891             exit(EXIT_FAILURE);
 892         }
 893         nbd_disconnect(nbdfd);
 894
 895         close(nbdfd);
 896
 897         printf("%s disconnected\n", argv[optind]);
 898
 899         return 0;
 900     }
 901 #endif
 902
 903     if ((device && !verbose) || fork_process) {
 904 #ifndef WIN32
 905         int stderr_fd[2];
 906         pid_t pid;
 907         int ret;
 908
 909         if (qemu_pipe(stderr_fd) < 0) {
 910             error_report("Error setting up communication pipe: %s",
 911                          strerror(errno));
 912             exit(EXIT_FAILURE);
 913         }
 914
 915         /* Now daemonize, but keep a communication channel open to
 916          * print errors and exit with the proper status code.
 917          */
 918         pid = fork();
 919         if (pid < 0) {
 920             error_report("Failed to fork: %s", strerror(errno));
 921             exit(EXIT_FAILURE);
 922         } else if (pid == 0) {
 923             close(stderr_fd[0]);
 924
 925             /* Remember parent's stderr if we will be restoring it. */
 926             if (fork_process) {
 927                 old_stderr = dup(STDERR_FILENO);
 928             }
 929
 930             ret = qemu_daemon(1, 0);
 931
 932             /* Temporarily redirect stderr to the parent's pipe...  */
 933             dup2(stderr_fd[1], STDERR_FILENO);
 934             if (ret < 0) {
 935                 error_report("Failed to daemonize: %s", strerror(errno));
 936                 exit(EXIT_FAILURE);
 937             }
 938
 939             /* ... close the descriptor we inherited and go on.  */
 940             close(stderr_fd[1]);
 941         } else {
 942             bool errors = false;
 943             char *buf;
 944
 945             /* In the parent.  Print error messages from the child until
 946              * it closes the pipe.
 947              */
 948             close(stderr_fd[1]);
 949             buf = g_malloc(1024);
 950             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 951                 errors = true;
 952                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 953                 if (ret < 0) {
 954                     exit(EXIT_FAILURE);
 955                 }
 956             }
 957             if (ret < 0) {
 958                 error_report("Cannot read from daemon: %s",
 959                              strerror(errno));
 960                 exit(EXIT_FAILURE);
 961             }
 962
 963             /* Usually the daemon should not print any message.
 964              * Exit with zero status in that case.
 965              */
 966             exit(errors);
 967         }
 968 #else /* WIN32 */
 969         error_report("Unable to fork into background on Windows hosts");
 970         exit(EXIT_FAILURE);
 971 #endif /* WIN32 */
 972     }
 973
 974     if (device != NULL && sockpath == NULL) {
 975         sockpath = g_malloc(128);
 976         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 977     }
 978
 979     server = qio_net_listener_new();
 980     if (socket_activation == 0) {
 981         int backlog;
 982
 983         if (persistent || shared == 0) {
 984             backlog = SOMAXCONN;
 985         } else {
 986             backlog = MIN(shared, SOMAXCONN);
 987         }
 988 #ifdef CONFIG_SELINUX
 989         if (selinux_label && setsockcreatecon_raw(selinux_label) == -1) {
 990             error_report("Cannot set SELinux socket create context to %s: %s",
 991                          selinux_label, strerror(errno));
 992             exit(EXIT_FAILURE);
 993         }
 994 #endif
 995         saddr = nbd_build_socket_address(sockpath, bindto, port);
 996         if (qio_net_listener_open_sync(server, saddr, backlog,
 997                                        &local_err) < 0) {
 998             object_unref(OBJECT(server));
 999             error_report_err(local_err);
1000             exit(EXIT_FAILURE);
1001         }
1002 #ifdef CONFIG_SELINUX
1003         if (selinux_label && setsockcreatecon_raw(NULL) == -1) {
1004             error_report("Cannot clear SELinux socket create context: %s",
1005                          strerror(errno));
1006             exit(EXIT_FAILURE);
1007         }
1008 #endif
1009     } else {
1010         size_t i;
1011         /* See comment in check_socket_activation above. */
1012         for (i = 0; i < socket_activation; i++) {
1013             QIOChannelSocket *sioc;
1014             sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
1015                                              &local_err);
1016             if (sioc == NULL) {
1017                 object_unref(OBJECT(server));
1018                 error_reportf_err(local_err,
1019                                   "Failed to use socket activation: ");
1020                 exit(EXIT_FAILURE);
1021             }
1022             qio_net_listener_add(server, sioc);
1023             object_unref(OBJECT(sioc));
1024         }
1025     }
1026
1027     qemu_init_main_loop(&error_fatal);
1028     bdrv_init();
1029     atexit(qemu_nbd_shutdown);
1030
1031     srcpath = argv[optind];
1032     if (imageOpts) {
1033         QemuOpts *opts;
1034         if (fmt) {
1035             error_report("--image-opts and -f are mutually exclusive");
1036             exit(EXIT_FAILURE);
1037         }
1038         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
1039         if (!opts) {
1040             qemu_opts_reset(&file_opts);
1041             exit(EXIT_FAILURE);
1042         }
1043         options = qemu_opts_to_qdict(opts, NULL);
1044         qemu_opts_reset(&file_opts);
1045         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
1046     } else {
1047         if (fmt) {
1048             options = qdict_new();
1049             qdict_put_str(options, "driver", fmt);
1050         }
1051         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
1052     }
1053
1054     if (!blk) {
1055         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
1056                           argv[optind]);
1057         exit(EXIT_FAILURE);
1058     }
1059     bs = blk_bs(blk);
1060
1061     if (dev_offset) {
1062         QDict *raw_opts = qdict_new();
1063         qdict_put_str(raw_opts, "driver", "raw");
1064         qdict_put_str(raw_opts, "file", bs->node_name);
1065         qdict_put_int(raw_opts, "offset", dev_offset);
1066         bs = bdrv_open(NULL, NULL, raw_opts, flags, &error_fatal);
1067         blk_remove_bs(blk);
1068         blk_insert_bs(blk, bs, &error_fatal);
1069         bdrv_unref(bs);
1070     }
1071
1072     blk_set_enable_write_cache(blk, !writethrough);
1073
1074     if (sn_opts) {
1075         ret = bdrv_snapshot_load_tmp(bs,
1076                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
1077                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
1078                                      &local_err);
1079     } else if (sn_id_or_name) {
1080         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
1081                                                    &local_err);
1082     }
1083     if (ret < 0) {
1084         error_reportf_err(local_err, "Failed to load snapshot: ");
1085         exit(EXIT_FAILURE);
1086     }
1087
1088     bs->detect_zeroes = detect_zeroes;
1089
1090     nbd_server_is_qemu_nbd(true);
1091
1092     export_opts = g_new(BlockExportOptions, 1);
1093     *export_opts = (BlockExportOptions) {
1094         .type               = BLOCK_EXPORT_TYPE_NBD,
1095         .id                 = g_strdup("qemu-nbd-export"),
1096         .node_name          = g_strdup(bdrv_get_node_name(bs)),
1097         .has_writethrough   = true,
1098         .writethrough       = writethrough,
1099         .has_writable       = true,
1100         .writable           = !readonly,
1101         .u.nbd = {
1102             .has_name             = true,
1103             .name                 = g_strdup(export_name),
1104             .has_description      = !!export_description,
1105             .description          = g_strdup(export_description),
1106             .has_bitmaps          = !!bitmaps,
1107             .bitmaps              = bitmaps,
1108             .has_allocation_depth = alloc_depth,
1109             .allocation_depth     = alloc_depth,
1110         },
1111     };
1112     blk_exp_add(export_opts, &error_fatal);
1113     qapi_free_BlockExportOptions(export_opts);
1114
1115     if (device) {
1116 #if HAVE_NBD_DEVICE
1117         int ret;
1118
1119         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1120         if (ret != 0) {
1121             error_report("Failed to create client thread: %s", strerror(ret));
1122             exit(EXIT_FAILURE);
1123         }
1124 #endif
1125     } else {
1126         /* Shut up GCC warnings.  */
1127         memset(&client_thread, 0, sizeof(client_thread));
1128     }
1129
1130     nbd_update_server_watch();
1131
1132     if (pid_file_name) {
1133         qemu_write_pidfile(pid_file_name, &error_fatal);
1134     }
1135
1136     /* now when the initialization is (almost) complete, chdir("/")
1137      * to free any busy filesystems */
1138     if (chdir("/") < 0) {
1139         error_report("Could not chdir to root directory: %s",
1140                      strerror(errno));
1141         exit(EXIT_FAILURE);
1142     }
1143
1144     if (fork_process) {
1145         dup2(old_stderr, STDERR_FILENO);
1146         close(old_stderr);
1147     }
1148
1149     state = RUNNING;
1150     do {
1151         main_loop_wait(false);
1152         if (state == TERMINATE) {
1153             blk_exp_close_all();
1154             state = TERMINATED;
1155         }
1156     } while (state != TERMINATED);
1157
1158     blk_unref(blk);
1159     if (sockpath) {
1160         unlink(sockpath);
1161     }
1162
1163     qemu_opts_del(sn_opts);
1164
1165     if (device) {
1166         void *ret;
1167         pthread_join(client_thread, &ret);
1168         exit(ret != NULL);
1169     } else {
1170         exit(EXIT_SUCCESS);
1171     }
1172 }