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 "qapi/error.h"
  25 #include "qemu/cutils.h"
  26 #include "sysemu/block-backend.h"
  27 #include "block/block_int.h"
  28 #include "block/nbd.h"
  29 #include "qemu/main-loop.h"
  30 #include "qemu/option.h"
  31 #include "qemu/error-report.h"
  32 #include "qemu/config-file.h"
  33 #include "qemu/bswap.h"
  34 #include "qemu/log.h"
  35 #include "qemu/systemd.h"
  36 #include "block/snapshot.h"
  37 #include "qapi/qmp/qdict.h"
  38 #include "qapi/qmp/qstring.h"
  39 #include "qom/object_interfaces.h"
  40 #include "io/channel-socket.h"
  41 #include "io/net-listener.h"
  42 #include "crypto/init.h"
  43 #include "trace/control.h"
  44 #include "qemu-version.h"
  45
  46 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  47 #define QEMU_NBD_OPT_CACHE         256
  48 #define QEMU_NBD_OPT_AIO           257
  49 #define QEMU_NBD_OPT_DISCARD       258
  50 #define QEMU_NBD_OPT_DETECT_ZEROES 259
  51 #define QEMU_NBD_OPT_OBJECT        260
  52 #define QEMU_NBD_OPT_TLSCREDS      261
  53 #define QEMU_NBD_OPT_IMAGE_OPTS    262
  54 #define QEMU_NBD_OPT_FORK          263
  55
  56 #define MBR_SIZE 512
  57
  58 static NBDExport *exp;
  59 static bool newproto;
  60 static int verbose;
  61 static char *srcpath;
  62 static SocketAddress *saddr;
  63 static int persistent = 0;
  64 static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  65 static int shared = 1;
  66 static int nb_fds;
  67 static QIONetListener *server;
  68 static QCryptoTLSCreds *tlscreds;
  69
  70 static void usage(const char *name)
  71 {
  72     (printf) (
  73 "Usage: %s [OPTIONS] FILE\n"
  74 "QEMU Disk Network Block Device Server\n"
  75 "\n"
  76 "  -h, --help                display this help and exit\n"
  77 "  -V, --version             output version information and exit\n"
  78 "\n"
  79 "Connection properties:\n"
  80 "  -p, --port=PORT           port to listen on (default `%d')\n"
  81 "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  82 "  -k, --socket=PATH         path to the unix socket\n"
  83 "                            (default '"SOCKET_PATH"')\n"
  84 "  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  85 "  -t, --persistent          don't exit on the last connection\n"
  86 "  -v, --verbose             display extra debugging information\n"
  87 "  -x, --export-name=NAME    expose export by name\n"
  88 "  -D, --description=TEXT    with -x, also export a human-readable description\n"
  89 "\n"
  90 "Exposing part of the image:\n"
  91 "  -o, --offset=OFFSET       offset into the image\n"
  92 "  -P, --partition=NUM       only expose partition NUM\n"
  93 "\n"
  94 "General purpose options:\n"
  95 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
  96 "                            passwords and/or encryption keys\n"
  97 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
  98 "                            specify tracing options\n"
  99 "  --fork                    fork off the server process and exit the parent\n"
 100 "                            once the server is running\n"
 101 #ifdef __linux__
 102 "Kernel NBD client support:\n"
 103 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
 104 "  -d, --disconnect          disconnect the specified device\n"
 105 "\n"
 106 #endif
 107 "\n"
 108 "Block device options:\n"
 109 "  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
 110 "  -r, --read-only           export read-only\n"
 111 "  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
 112 "                            file with backing_file=FILE, redirect the write to\n"
 113 "                            the temporary one\n"
 114 "  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 115 "                            load an internal snapshot inside FILE and export it\n"
 116 "                            as an read-only device, SNAPSHOT_PARAM format is\n"
 117 "                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 118 "                            '[ID_OR_NAME]'\n"
 119 "  -n, --nocache             disable host cache\n"
 120 "      --cache=MODE          set cache mode (none, writeback, ...)\n"
 121 "      --aio=MODE            set AIO mode (native or threads)\n"
 122 "      --discard=MODE        set discard mode (ignore, unmap)\n"
 123 "      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 124 "      --image-opts          treat FILE as a full set of image options\n"
 125 "\n"
 126 QEMU_HELP_BOTTOM "\n"
 127     , name, NBD_DEFAULT_PORT, "DEVICE");
 128 }
 129
 130 static void version(const char *name)
 131 {
 132     printf(
 133 "%s " QEMU_FULL_VERSION "\n"
 134 "Written by Anthony Liguori.\n"
 135 "\n"
 136 QEMU_COPYRIGHT "\n"
 137 "This is free software; see the source for copying conditions.  There is NO\n"
 138 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 139     , name);
 140 }
 141
 142 struct partition_record
 143 {
 144     uint8_t bootable;
 145     uint8_t start_head;
 146     uint32_t start_cylinder;
 147     uint8_t start_sector;
 148     uint8_t system;
 149     uint8_t end_head;
 150     uint8_t end_cylinder;
 151     uint8_t end_sector;
 152     uint32_t start_sector_abs;
 153     uint32_t nb_sectors_abs;
 154 };
 155
 156 static void read_partition(uint8_t *p, struct partition_record *r)
 157 {
 158     r->bootable = p[0];
 159     r->start_head = p[1];
 160     r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 161     r->start_sector = p[2] & 0x3f;
 162     r->system = p[4];
 163     r->end_head = p[5];
 164     r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 165     r->end_sector = p[6] & 0x3f;
 166
 167     r->start_sector_abs = ldl_le_p(p + 8);
 168     r->nb_sectors_abs   = ldl_le_p(p + 12);
 169 }
 170
 171 static int find_partition(BlockBackend *blk, int partition,
 172                           off_t *offset, off_t *size)
 173 {
 174     struct partition_record mbr[4];
 175     uint8_t data[MBR_SIZE];
 176     int i;
 177     int ext_partnum = 4;
 178     int ret;
 179
 180     ret = blk_pread(blk, 0, data, sizeof(data));
 181     if (ret < 0) {
 182         error_report("error while reading: %s", strerror(-ret));
 183         exit(EXIT_FAILURE);
 184     }
 185
 186     if (data[510] != 0x55 || data[511] != 0xaa) {
 187         return -EINVAL;
 188     }
 189
 190     for (i = 0; i < 4; i++) {
 191         read_partition(&data[446 + 16 * i], &mbr[i]);
 192
 193         if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
 194             continue;
 195         }
 196
 197         if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 198             struct partition_record ext[4];
 199             uint8_t data1[MBR_SIZE];
 200             int j;
 201
 202             ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE,
 203                             data1, sizeof(data1));
 204             if (ret < 0) {
 205                 error_report("error while reading: %s", strerror(-ret));
 206                 exit(EXIT_FAILURE);
 207             }
 208
 209             for (j = 0; j < 4; j++) {
 210                 read_partition(&data1[446 + 16 * j], &ext[j]);
 211                 if (!ext[j].system || !ext[j].nb_sectors_abs) {
 212                     continue;
 213                 }
 214
 215                 if ((ext_partnum + j + 1) == partition) {
 216                     *offset = (uint64_t)ext[j].start_sector_abs << 9;
 217                     *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 218                     return 0;
 219                 }
 220             }
 221             ext_partnum += 4;
 222         } else if ((i + 1) == partition) {
 223             *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 224             *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 225             return 0;
 226         }
 227     }
 228
 229     return -ENOENT;
 230 }
 231
 232 static void termsig_handler(int signum)
 233 {
 234     atomic_cmpxchg(&state, RUNNING, TERMINATE);
 235     qemu_notify_event();
 236 }
 237
 238
 239 static void *show_parts(void *arg)
 240 {
 241     char *device = arg;
 242     int nbd;
 243
 244     /* linux just needs an open() to trigger
 245      * the partition table update
 246      * but remember to load the module with max_part != 0 :
 247      *     modprobe nbd max_part=63
 248      */
 249     nbd = open(device, O_RDWR);
 250     if (nbd >= 0) {
 251         close(nbd);
 252     }
 253     return NULL;
 254 }
 255
 256 static void *nbd_client_thread(void *arg)
 257 {
 258     char *device = arg;
 259     NBDExportInfo info = { .request_sizes = false, };
 260     QIOChannelSocket *sioc;
 261     int fd;
 262     int ret;
 263     pthread_t show_parts_thread;
 264     Error *local_error = NULL;
 265
 266     sioc = qio_channel_socket_new();
 267     if (qio_channel_socket_connect_sync(sioc,
 268                                         saddr,
 269                                         &local_error) < 0) {
 270         error_report_err(local_error);
 271         goto out;
 272     }
 273
 274     ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), NULL,
 275                                 NULL, NULL, NULL, &info, &local_error);
 276     if (ret < 0) {
 277         if (local_error) {
 278             error_report_err(local_error);
 279         }
 280         goto out_socket;
 281     }
 282
 283     fd = open(device, O_RDWR);
 284     if (fd < 0) {
 285         /* Linux-only, we can use %m in printf.  */
 286         error_report("Failed to open %s: %m", device);
 287         goto out_socket;
 288     }
 289
 290     ret = nbd_init(fd, sioc, &info, &local_error);
 291     if (ret < 0) {
 292         error_report_err(local_error);
 293         goto out_fd;
 294     }
 295
 296     /* update partition table */
 297     pthread_create(&show_parts_thread, NULL, show_parts, device);
 298
 299     if (verbose) {
 300         fprintf(stderr, "NBD device %s is now connected to %s\n",
 301                 device, srcpath);
 302     } else {
 303         /* Close stderr so that the qemu-nbd process exits.  */
 304         dup2(STDOUT_FILENO, STDERR_FILENO);
 305     }
 306
 307     ret = nbd_client(fd);
 308     if (ret) {
 309         goto out_fd;
 310     }
 311     close(fd);
 312     object_unref(OBJECT(sioc));
 313     kill(getpid(), SIGTERM);
 314     return (void *) EXIT_SUCCESS;
 315
 316 out_fd:
 317     close(fd);
 318 out_socket:
 319     object_unref(OBJECT(sioc));
 320 out:
 321     kill(getpid(), SIGTERM);
 322     return (void *) EXIT_FAILURE;
 323 }
 324
 325 static int nbd_can_accept(void)
 326 {
 327     return state == RUNNING && nb_fds < shared;
 328 }
 329
 330 static void nbd_export_closed(NBDExport *exp)
 331 {
 332     assert(state == TERMINATING);
 333     state = TERMINATED;
 334 }
 335
 336 static void nbd_update_server_watch(void);
 337
 338 static void nbd_client_closed(NBDClient *client, bool negotiated)
 339 {
 340     nb_fds--;
 341     if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
 342         state = TERMINATE;
 343     }
 344     nbd_update_server_watch();
 345     nbd_client_put(client);
 346 }
 347
 348 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
 349                        gpointer opaque)
 350 {
 351     if (state >= TERMINATE) {
 352         return;
 353     }
 354
 355     nb_fds++;
 356     nbd_update_server_watch();
 357     nbd_client_new(newproto ? NULL : exp, cioc,
 358                    tlscreds, NULL, 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 QemuOptsList qemu_object_opts = {
 408     .name = "object",
 409     .implied_opt_name = "qom-type",
 410     .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 411     .desc = {
 412         { }
 413     },
 414 };
 415
 416
 417
 418 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 419 {
 420     Object *obj;
 421     QCryptoTLSCreds *creds;
 422
 423     obj = object_resolve_path_component(
 424         object_get_objects_root(), id);
 425     if (!obj) {
 426         error_setg(errp, "No TLS credentials with id '%s'",
 427                    id);
 428         return NULL;
 429     }
 430     creds = (QCryptoTLSCreds *)
 431         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 432     if (!creds) {
 433         error_setg(errp, "Object with id '%s' is not TLS credentials",
 434                    id);
 435         return NULL;
 436     }
 437
 438     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
 439         error_setg(errp,
 440                    "Expecting TLS credentials with a server endpoint");
 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 {
 466     if (device != NULL) {
 467         return "NBD device can't be set when using socket activation";
 468     }
 469
 470     if (sockpath != NULL) {
 471         return "Unix socket can't be set when using socket activation";
 472     }
 473
 474     if (address != NULL) {
 475         return "The interface can't be set when using socket activation";
 476     }
 477
 478     if (port != NULL) {
 479         return "TCP port number can't be set when using socket activation";
 480     }
 481
 482     return NULL;
 483 }
 484
 485 static void qemu_nbd_shutdown(void)
 486 {
 487     job_cancel_sync_all();
 488     bdrv_close_all();
 489 }
 490
 491 int main(int argc, char **argv)
 492 {
 493     BlockBackend *blk;
 494     BlockDriverState *bs;
 495     off_t dev_offset = 0;
 496     uint16_t nbdflags = 0;
 497     bool disconnect = false;
 498     const char *bindto = NULL;
 499     const char *port = NULL;
 500     char *sockpath = NULL;
 501     char *device = NULL;
 502     off_t fd_size;
 503     QemuOpts *sn_opts = NULL;
 504     const char *sn_id_or_name = NULL;
 505     const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:";
 506     struct option lopt[] = {
 507         { "help", no_argument, NULL, 'h' },
 508         { "version", no_argument, NULL, 'V' },
 509         { "bind", required_argument, NULL, 'b' },
 510         { "port", required_argument, NULL, 'p' },
 511         { "socket", required_argument, NULL, 'k' },
 512         { "offset", required_argument, NULL, 'o' },
 513         { "read-only", no_argument, NULL, 'r' },
 514         { "partition", required_argument, NULL, 'P' },
 515         { "connect", required_argument, NULL, 'c' },
 516         { "disconnect", no_argument, NULL, 'd' },
 517         { "snapshot", no_argument, NULL, 's' },
 518         { "load-snapshot", required_argument, NULL, 'l' },
 519         { "nocache", no_argument, NULL, 'n' },
 520         { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 521         { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 522         { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 523         { "detect-zeroes", required_argument, NULL,
 524           QEMU_NBD_OPT_DETECT_ZEROES },
 525         { "shared", required_argument, NULL, 'e' },
 526         { "format", required_argument, NULL, 'f' },
 527         { "persistent", no_argument, NULL, 't' },
 528         { "verbose", no_argument, NULL, 'v' },
 529         { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 530         { "export-name", required_argument, NULL, 'x' },
 531         { "description", required_argument, NULL, 'D' },
 532         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 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         { NULL, 0, NULL, 0 }
 537     };
 538     int ch;
 539     int opt_ind = 0;
 540     char *end;
 541     int flags = BDRV_O_RDWR;
 542     int partition = -1;
 543     int ret = 0;
 544     bool seen_cache = false;
 545     bool seen_discard = false;
 546     bool seen_aio = false;
 547     pthread_t client_thread;
 548     const char *fmt = NULL;
 549     Error *local_err = NULL;
 550     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 551     QDict *options = NULL;
 552     const char *export_name = NULL;
 553     const char *export_description = NULL;
 554     const char *tlscredsid = NULL;
 555     bool imageOpts = false;
 556     bool writethrough = true;
 557     char *trace_file = NULL;
 558     bool fork_process = false;
 559     int old_stderr = -1;
 560     unsigned socket_activation;
 561
 562     /* The client thread uses SIGTERM to interrupt the server.  A signal
 563      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 564      */
 565     struct sigaction sa_sigterm;
 566     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 567     sa_sigterm.sa_handler = termsig_handler;
 568     sigaction(SIGTERM, &sa_sigterm, NULL);
 569
 570 #ifdef CONFIG_POSIX
 571     signal(SIGPIPE, SIG_IGN);
 572 #endif
 573
 574     module_call_init(MODULE_INIT_TRACE);
 575     qcrypto_init(&error_fatal);
 576
 577     module_call_init(MODULE_INIT_QOM);
 578     qemu_add_opts(&qemu_object_opts);
 579     qemu_add_opts(&qemu_trace_opts);
 580     qemu_init_exec_dir(argv[0]);
 581
 582     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 583         switch (ch) {
 584         case 's':
 585             flags |= BDRV_O_SNAPSHOT;
 586             break;
 587         case 'n':
 588             optarg = (char *) "none";
 589             /* fallthrough */
 590         case QEMU_NBD_OPT_CACHE:
 591             if (seen_cache) {
 592                 error_report("-n and --cache can only be specified once");
 593                 exit(EXIT_FAILURE);
 594             }
 595             seen_cache = true;
 596             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 597                 error_report("Invalid cache mode `%s'", optarg);
 598                 exit(EXIT_FAILURE);
 599             }
 600             break;
 601         case QEMU_NBD_OPT_AIO:
 602             if (seen_aio) {
 603                 error_report("--aio can only be specified once");
 604                 exit(EXIT_FAILURE);
 605             }
 606             seen_aio = true;
 607             if (!strcmp(optarg, "native")) {
 608                 flags |= BDRV_O_NATIVE_AIO;
 609             } else if (!strcmp(optarg, "threads")) {
 610                 /* this is the default */
 611             } else {
 612                error_report("invalid aio mode `%s'", optarg);
 613                exit(EXIT_FAILURE);
 614             }
 615             break;
 616         case QEMU_NBD_OPT_DISCARD:
 617             if (seen_discard) {
 618                 error_report("--discard can only be specified once");
 619                 exit(EXIT_FAILURE);
 620             }
 621             seen_discard = true;
 622             if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 623                 error_report("Invalid discard mode `%s'", optarg);
 624                 exit(EXIT_FAILURE);
 625             }
 626             break;
 627         case QEMU_NBD_OPT_DETECT_ZEROES:
 628             detect_zeroes =
 629                 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
 630                                 optarg,
 631                                 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 632                                 &local_err);
 633             if (local_err) {
 634                 error_reportf_err(local_err,
 635                                   "Failed to parse detect_zeroes mode: ");
 636                 exit(EXIT_FAILURE);
 637             }
 638             if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 639                 !(flags & BDRV_O_UNMAP)) {
 640                 error_report("setting detect-zeroes to unmap is not allowed "
 641                              "without setting discard operation to unmap");
 642                 exit(EXIT_FAILURE);
 643             }
 644             break;
 645         case 'b':
 646             bindto = optarg;
 647             break;
 648         case 'p':
 649             port = optarg;
 650             break;
 651         case 'o':
 652                 dev_offset = strtoll (optarg, &end, 0);
 653             if (*end) {
 654                 error_report("Invalid offset `%s'", optarg);
 655                 exit(EXIT_FAILURE);
 656             }
 657             if (dev_offset < 0) {
 658                 error_report("Offset must be positive `%s'", optarg);
 659                 exit(EXIT_FAILURE);
 660             }
 661             break;
 662         case 'l':
 663             if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 664                 sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 665                                                   optarg, false);
 666                 if (!sn_opts) {
 667                     error_report("Failed in parsing snapshot param `%s'",
 668                                  optarg);
 669                     exit(EXIT_FAILURE);
 670                 }
 671             } else {
 672                 sn_id_or_name = optarg;
 673             }
 674             /* fall through */
 675         case 'r':
 676             nbdflags |= NBD_FLAG_READ_ONLY;
 677             flags &= ~BDRV_O_RDWR;
 678             break;
 679         case 'P':
 680             partition = strtol(optarg, &end, 0);
 681             if (*end) {
 682                 error_report("Invalid partition `%s'", optarg);
 683                 exit(EXIT_FAILURE);
 684             }
 685             if (partition < 1 || partition > 8) {
 686                 error_report("Invalid partition %d", partition);
 687                 exit(EXIT_FAILURE);
 688             }
 689             break;
 690         case 'k':
 691             sockpath = optarg;
 692             if (sockpath[0] != '/') {
 693                 error_report("socket path must be absolute");
 694                 exit(EXIT_FAILURE);
 695             }
 696             break;
 697         case 'd':
 698             disconnect = true;
 699             break;
 700         case 'c':
 701             device = optarg;
 702             break;
 703         case 'e':
 704             shared = strtol(optarg, &end, 0);
 705             if (*end) {
 706                 error_report("Invalid shared device number '%s'", optarg);
 707                 exit(EXIT_FAILURE);
 708             }
 709             if (shared < 1) {
 710                 error_report("Shared device number must be greater than 0");
 711                 exit(EXIT_FAILURE);
 712             }
 713             break;
 714         case 'f':
 715             fmt = optarg;
 716             break;
 717         case 't':
 718             persistent = 1;
 719             break;
 720         case 'x':
 721             export_name = optarg;
 722             break;
 723         case 'D':
 724             export_description = optarg;
 725             break;
 726         case 'v':
 727             verbose = 1;
 728             break;
 729         case 'V':
 730             version(argv[0]);
 731             exit(0);
 732             break;
 733         case 'h':
 734             usage(argv[0]);
 735             exit(0);
 736             break;
 737         case '?':
 738             error_report("Try `%s --help' for more information.", argv[0]);
 739             exit(EXIT_FAILURE);
 740         case QEMU_NBD_OPT_OBJECT: {
 741             QemuOpts *opts;
 742             opts = qemu_opts_parse_noisily(&qemu_object_opts,
 743                                            optarg, true);
 744             if (!opts) {
 745                 exit(EXIT_FAILURE);
 746             }
 747         }   break;
 748         case QEMU_NBD_OPT_TLSCREDS:
 749             tlscredsid = optarg;
 750             break;
 751         case QEMU_NBD_OPT_IMAGE_OPTS:
 752             imageOpts = true;
 753             break;
 754         case 'T':
 755             g_free(trace_file);
 756             trace_file = trace_opt_parse(optarg);
 757             break;
 758         case QEMU_NBD_OPT_FORK:
 759             fork_process = true;
 760             break;
 761         }
 762     }
 763
 764     if ((argc - optind) != 1) {
 765         error_report("Invalid number of arguments");
 766         error_printf("Try `%s --help' for more information.\n", argv[0]);
 767         exit(EXIT_FAILURE);
 768     }
 769
 770     if (qemu_opts_foreach(&qemu_object_opts,
 771                           user_creatable_add_opts_foreach,
 772                           NULL, NULL)) {
 773         exit(EXIT_FAILURE);
 774     }
 775
 776     if (!trace_init_backends()) {
 777         exit(1);
 778     }
 779     trace_init_file(trace_file);
 780     qemu_set_log(LOG_TRACE);
 781
 782     socket_activation = check_socket_activation();
 783     if (socket_activation == 0) {
 784         setup_address_and_port(&bindto, &port);
 785     } else {
 786         /* Using socket activation - check user didn't use -p etc. */
 787         const char *err_msg = socket_activation_validate_opts(device, sockpath,
 788                                                               bindto, port);
 789         if (err_msg != NULL) {
 790             error_report("%s", err_msg);
 791             exit(EXIT_FAILURE);
 792         }
 793
 794         /* qemu-nbd can only listen on a single socket.  */
 795         if (socket_activation > 1) {
 796             error_report("qemu-nbd does not support socket activation with %s > 1",
 797                          "LISTEN_FDS");
 798             exit(EXIT_FAILURE);
 799         }
 800     }
 801
 802     if (tlscredsid) {
 803         if (sockpath) {
 804             error_report("TLS is only supported with IPv4/IPv6");
 805             exit(EXIT_FAILURE);
 806         }
 807         if (device) {
 808             error_report("TLS is not supported with a host device");
 809             exit(EXIT_FAILURE);
 810         }
 811         if (!export_name) {
 812             /* Set the default NBD protocol export name, since
 813              * we *must* use new style protocol for TLS */
 814             export_name = "";
 815         }
 816         tlscreds = nbd_get_tls_creds(tlscredsid, &local_err);
 817         if (local_err) {
 818             error_report("Failed to get TLS creds %s",
 819                          error_get_pretty(local_err));
 820             exit(EXIT_FAILURE);
 821         }
 822     }
 823
 824     if (disconnect) {
 825         int nbdfd = open(argv[optind], O_RDWR);
 826         if (nbdfd < 0) {
 827             error_report("Cannot open %s: %s", argv[optind],
 828                          strerror(errno));
 829             exit(EXIT_FAILURE);
 830         }
 831         nbd_disconnect(nbdfd);
 832
 833         close(nbdfd);
 834
 835         printf("%s disconnected\n", argv[optind]);
 836
 837         return 0;
 838     }
 839
 840     if ((device && !verbose) || fork_process) {
 841         int stderr_fd[2];
 842         pid_t pid;
 843         int ret;
 844
 845         if (qemu_pipe(stderr_fd) < 0) {
 846             error_report("Error setting up communication pipe: %s",
 847                          strerror(errno));
 848             exit(EXIT_FAILURE);
 849         }
 850
 851         /* Now daemonize, but keep a communication channel open to
 852          * print errors and exit with the proper status code.
 853          */
 854         pid = fork();
 855         if (pid < 0) {
 856             error_report("Failed to fork: %s", strerror(errno));
 857             exit(EXIT_FAILURE);
 858         } else if (pid == 0) {
 859             close(stderr_fd[0]);
 860             ret = qemu_daemon(1, 0);
 861
 862             /* Temporarily redirect stderr to the parent's pipe...  */
 863             old_stderr = dup(STDERR_FILENO);
 864             dup2(stderr_fd[1], STDERR_FILENO);
 865             if (ret < 0) {
 866                 error_report("Failed to daemonize: %s", strerror(errno));
 867                 exit(EXIT_FAILURE);
 868             }
 869
 870             /* ... close the descriptor we inherited and go on.  */
 871             close(stderr_fd[1]);
 872         } else {
 873             bool errors = false;
 874             char *buf;
 875
 876             /* In the parent.  Print error messages from the child until
 877              * it closes the pipe.
 878              */
 879             close(stderr_fd[1]);
 880             buf = g_malloc(1024);
 881             while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 882                 errors = true;
 883                 ret = qemu_write_full(STDERR_FILENO, buf, ret);
 884                 if (ret < 0) {
 885                     exit(EXIT_FAILURE);
 886                 }
 887             }
 888             if (ret < 0) {
 889                 error_report("Cannot read from daemon: %s",
 890                              strerror(errno));
 891                 exit(EXIT_FAILURE);
 892             }
 893
 894             /* Usually the daemon should not print any message.
 895              * Exit with zero status in that case.
 896              */
 897             exit(errors);
 898         }
 899     }
 900
 901     if (device != NULL && sockpath == NULL) {
 902         sockpath = g_malloc(128);
 903         snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 904     }
 905
 906     server = qio_net_listener_new();
 907     if (socket_activation == 0) {
 908         saddr = nbd_build_socket_address(sockpath, bindto, port);
 909         if (qio_net_listener_open_sync(server, saddr, &local_err) < 0) {
 910             object_unref(OBJECT(server));
 911             error_report_err(local_err);
 912             exit(EXIT_FAILURE);
 913         }
 914     } else {
 915         size_t i;
 916         /* See comment in check_socket_activation above. */
 917         for (i = 0; i < socket_activation; i++) {
 918             QIOChannelSocket *sioc;
 919             sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
 920                                              &local_err);
 921             if (sioc == NULL) {
 922                 object_unref(OBJECT(server));
 923                 error_report("Failed to use socket activation: %s",
 924                              error_get_pretty(local_err));
 925                 exit(EXIT_FAILURE);
 926             }
 927             qio_net_listener_add(server, sioc);
 928             object_unref(OBJECT(sioc));
 929         }
 930     }
 931
 932     if (qemu_init_main_loop(&local_err)) {
 933         error_report_err(local_err);
 934         exit(EXIT_FAILURE);
 935     }
 936     bdrv_init();
 937     atexit(qemu_nbd_shutdown);
 938
 939     srcpath = argv[optind];
 940     if (imageOpts) {
 941         QemuOpts *opts;
 942         if (fmt) {
 943             error_report("--image-opts and -f are mutually exclusive");
 944             exit(EXIT_FAILURE);
 945         }
 946         opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
 947         if (!opts) {
 948             qemu_opts_reset(&file_opts);
 949             exit(EXIT_FAILURE);
 950         }
 951         options = qemu_opts_to_qdict(opts, NULL);
 952         qemu_opts_reset(&file_opts);
 953         blk = blk_new_open(NULL, NULL, options, flags, &local_err);
 954     } else {
 955         if (fmt) {
 956             options = qdict_new();
 957             qdict_put_str(options, "driver", fmt);
 958         }
 959         blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
 960     }
 961
 962     if (!blk) {
 963         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
 964                           argv[optind]);
 965         exit(EXIT_FAILURE);
 966     }
 967     bs = blk_bs(blk);
 968
 969     blk_set_enable_write_cache(blk, !writethrough);
 970
 971     if (sn_opts) {
 972         ret = bdrv_snapshot_load_tmp(bs,
 973                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 974                                      qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 975                                      &local_err);
 976     } else if (sn_id_or_name) {
 977         ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 978                                                    &local_err);
 979     }
 980     if (ret < 0) {
 981         error_reportf_err(local_err, "Failed to load snapshot: ");
 982         exit(EXIT_FAILURE);
 983     }
 984
 985     bs->detect_zeroes = detect_zeroes;
 986     fd_size = blk_getlength(blk);
 987     if (fd_size < 0) {
 988         error_report("Failed to determine the image length: %s",
 989                      strerror(-fd_size));
 990         exit(EXIT_FAILURE);
 991     }
 992
 993     if (dev_offset >= fd_size) {
 994         error_report("Offset (%lld) has to be smaller than the image size "
 995                      "(%lld)",
 996                      (long long int)dev_offset, (long long int)fd_size);
 997         exit(EXIT_FAILURE);
 998     }
 999     fd_size -= dev_offset;
1000
1001     if (partition != -1) {
1002         ret = find_partition(blk, partition, &dev_offset, &fd_size);
1003         if (ret < 0) {
1004             error_report("Could not find partition %d: %s", partition,
1005                          strerror(-ret));
1006             exit(EXIT_FAILURE);
1007         }
1008     }
1009
1010     exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed,
1011                          writethrough, NULL, &local_err);
1012     if (!exp) {
1013         error_report_err(local_err);
1014         exit(EXIT_FAILURE);
1015     }
1016     if (export_name) {
1017         nbd_export_set_name(exp, export_name);
1018         nbd_export_set_description(exp, export_description);
1019         newproto = true;
1020     } else if (export_description) {
1021         error_report("Export description requires an export name");
1022         exit(EXIT_FAILURE);
1023     }
1024
1025     if (device) {
1026         int ret;
1027
1028         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1029         if (ret != 0) {
1030             error_report("Failed to create client thread: %s", strerror(ret));
1031             exit(EXIT_FAILURE);
1032         }
1033     } else {
1034         /* Shut up GCC warnings.  */
1035         memset(&client_thread, 0, sizeof(client_thread));
1036     }
1037
1038     nbd_update_server_watch();
1039
1040     /* now when the initialization is (almost) complete, chdir("/")
1041      * to free any busy filesystems */
1042     if (chdir("/") < 0) {
1043         error_report("Could not chdir to root directory: %s",
1044                      strerror(errno));
1045         exit(EXIT_FAILURE);
1046     }
1047
1048     if (fork_process) {
1049         dup2(old_stderr, STDERR_FILENO);
1050         close(old_stderr);
1051     }
1052
1053     state = RUNNING;
1054     do {
1055         main_loop_wait(false);
1056         if (state == TERMINATE) {
1057             state = TERMINATING;
1058             nbd_export_close(exp);
1059             nbd_export_put(exp);
1060             exp = NULL;
1061         }
1062     } while (state != TERMINATED);
1063
1064     blk_unref(blk);
1065     if (sockpath) {
1066         unlink(sockpath);
1067     }
1068
1069     qemu_opts_del(sn_opts);
1070
1071     if (device) {
1072         void *ret;
1073         pthread_join(client_thread, &ret);
1074         exit(ret != NULL);
1075     } else {
1076         exit(EXIT_SUCCESS);
1077     }
1078 }