qemu/qemu-nbd.c
<<
>>
Prefs
   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 "block/block_int.h"
  29#include "block/nbd.h"
  30#include "qemu/main-loop.h"
  31#include "qemu/module.h"
  32#include "qemu/option.h"
  33#include "qemu/error-report.h"
  34#include "qemu/config-file.h"
  35#include "qemu/bswap.h"
  36#include "qemu/log.h"
  37#include "qemu/systemd.h"
  38#include "block/snapshot.h"
  39#include "qapi/qmp/qdict.h"
  40#include "qapi/qmp/qstring.h"
  41#include "qom/object_interfaces.h"
  42#include "io/channel-socket.h"
  43#include "io/net-listener.h"
  44#include "crypto/init.h"
  45#include "trace/control.h"
  46#include "qemu-version.h"
  47
  48#ifdef __linux__
  49#define HAVE_NBD_DEVICE 1
  50#else
  51#define HAVE_NBD_DEVICE 0
  52#endif
  53
  54#define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  55#define QEMU_NBD_OPT_CACHE         256
  56#define QEMU_NBD_OPT_AIO           257
  57#define QEMU_NBD_OPT_DISCARD       258
  58#define QEMU_NBD_OPT_DETECT_ZEROES 259
  59#define QEMU_NBD_OPT_OBJECT        260
  60#define QEMU_NBD_OPT_TLSCREDS      261
  61#define QEMU_NBD_OPT_IMAGE_OPTS    262
  62#define QEMU_NBD_OPT_FORK          263
  63#define QEMU_NBD_OPT_TLSAUTHZ      264
  64#define QEMU_NBD_OPT_PID_FILE      265
  65
  66#define MBR_SIZE 512
  67
  68static NBDExport *export;
  69static int verbose;
  70static char *srcpath;
  71static SocketAddress *saddr;
  72static int persistent = 0;
  73static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  74static int shared = 1;
  75static int nb_fds;
  76static QIONetListener *server;
  77static QCryptoTLSCreds *tlscreds;
  78static const char *tlsauthz;
  79
  80static void usage(const char *name)
  81{
  82    (printf) (
  83"Usage: %s [OPTIONS] FILE\n"
  84"  or:  %s -L [OPTIONS]\n"
  85"QEMU Disk Network Block Device Utility\n"
  86"\n"
  87"  -h, --help                display this help and exit\n"
  88"  -V, --version             output version information and exit\n"
  89"\n"
  90"Connection properties:\n"
  91"  -p, --port=PORT           port to listen on (default `%d')\n"
  92"  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  93"  -k, --socket=PATH         path to the unix socket\n"
  94"                            (default '"SOCKET_PATH"')\n"
  95"  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  96"  -t, --persistent          don't exit on the last connection\n"
  97"  -v, --verbose             display extra debugging information\n"
  98"  -x, --export-name=NAME    expose export by name (default is empty string)\n"
  99"  -D, --description=TEXT    export a human-readable description\n"
 100"\n"
 101"Exposing part of the image:\n"
 102"  -o, --offset=OFFSET       offset into the image\n"
 103"  -B, --bitmap=NAME         expose a persistent dirty bitmap\n"
 104"\n"
 105"General purpose options:\n"
 106"  -L, --list                list exports available from another NBD server\n"
 107"  --object type,id=ID,...   define an object such as 'secret' for providing\n"
 108"                            passwords and/or encryption keys\n"
 109"  --tls-creds=ID            use id of an earlier --object to provide TLS\n"
 110"  --tls-authz=ID            use id of an earlier --object to provide\n"
 111"                            authorization\n"
 112"  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
 113"                            specify tracing options\n"
 114"  --fork                    fork off the server process and exit the parent\n"
 115"                            once the server is running\n"
 116"  --pid-file=PATH           store the server's process ID in the given file\n"
 117#if HAVE_NBD_DEVICE
 118"\n"
 119"Kernel NBD client support:\n"
 120"  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
 121"  -d, --disconnect          disconnect the specified device\n"
 122#endif
 123"\n"
 124"Block device options:\n"
 125"  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
 126"  -r, --read-only           export read-only\n"
 127"  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
 128"                            file with backing_file=FILE, redirect the write to\n"
 129"                            the temporary one\n"
 130"  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 131"                            load an internal snapshot inside FILE and export it\n"
 132"                            as an read-only device, SNAPSHOT_PARAM format is\n"
 133"                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 134"                            '[ID_OR_NAME]'\n"
 135"  -n, --nocache             disable host cache\n"
 136"      --cache=MODE          set cache mode (none, writeback, ...)\n"
 137"      --aio=MODE            set AIO mode (native, io_uring or threads)\n"
 138"      --discard=MODE        set discard mode (ignore, unmap)\n"
 139"      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 140"      --image-opts          treat FILE as a full set of image options\n"
 141"\n"
 142QEMU_HELP_BOTTOM "\n"
 143    , name, name, NBD_DEFAULT_PORT, "DEVICE");
 144}
 145
 146static void version(const char *name)
 147{
 148    printf(
 149"%s " QEMU_FULL_VERSION "\n"
 150"Written by Anthony Liguori.\n"
 151"\n"
 152QEMU_COPYRIGHT "\n"
 153"This is free software; see the source for copying conditions.  There is NO\n"
 154"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 155    , name);
 156}
 157
 158static void termsig_handler(int signum)
 159{
 160    atomic_cmpxchg(&state, RUNNING, TERMINATE);
 161    qemu_notify_event();
 162}
 163
 164
 165static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
 166                                const char *hostname)
 167{
 168    int ret = EXIT_FAILURE;
 169    int rc;
 170    Error *err = NULL;
 171    QIOChannelSocket *sioc;
 172    NBDExportInfo *list;
 173    int i, j;
 174
 175    sioc = qio_channel_socket_new();
 176    if (qio_channel_socket_connect_sync(sioc, saddr, &err) < 0) {
 177        error_report_err(err);
 178        return EXIT_FAILURE;
 179    }
 180    rc = nbd_receive_export_list(QIO_CHANNEL(sioc), tls, hostname, &list,
 181                                 &err);
 182    if (rc < 0) {
 183        if (err) {
 184            error_report_err(err);
 185        }
 186        goto out;
 187    }
 188    printf("exports available: %d\n", rc);
 189    for (i = 0; i < rc; i++) {
 190        printf(" export: '%s'\n", list[i].name);
 191        if (list[i].description && *list[i].description) {
 192            printf("  description: %s\n", list[i].description);
 193        }
 194        if (list[i].flags & NBD_FLAG_HAS_FLAGS) {
 195            static const char *const flag_names[] = {
 196                [NBD_FLAG_READ_ONLY_BIT]            = "readonly",
 197                [NBD_FLAG_SEND_FLUSH_BIT]           = "flush",
 198                [NBD_FLAG_SEND_FUA_BIT]             = "fua",
 199                [NBD_FLAG_ROTATIONAL_BIT]           = "rotational",
 200                [NBD_FLAG_SEND_TRIM_BIT]            = "trim",
 201                [NBD_FLAG_SEND_WRITE_ZEROES_BIT]    = "zeroes",
 202                [NBD_FLAG_SEND_DF_BIT]              = "df",
 203                [NBD_FLAG_CAN_MULTI_CONN_BIT]       = "multi",
 204                [NBD_FLAG_SEND_RESIZE_BIT]          = "resize",
 205                [NBD_FLAG_SEND_CACHE_BIT]           = "cache",
 206                [NBD_FLAG_SEND_FAST_ZERO_BIT]       = "fast-zero",
 207            };
 208
 209            printf("  size:  %" PRIu64 "\n", list[i].size);
 210            printf("  flags: 0x%x (", list[i].flags);
 211            for (size_t bit = 0; bit < ARRAY_SIZE(flag_names); bit++) {
 212                if (flag_names[bit] && (list[i].flags & (1 << bit))) {
 213                    printf(" %s", flag_names[bit]);
 214                }
 215            }
 216            printf(" )\n");
 217        }
 218        if (list[i].min_block) {
 219            printf("  min block: %u\n", list[i].min_block);
 220            printf("  opt block: %u\n", list[i].opt_block);
 221            printf("  max block: %u\n", list[i].max_block);
 222        }
 223        if (list[i].n_contexts) {
 224            printf("  available meta contexts: %d\n", list[i].n_contexts);
 225            for (j = 0; j < list[i].n_contexts; j++) {
 226                printf("   %s\n", list[i].contexts[j]);
 227            }
 228        }
 229    }
 230    nbd_free_export_list(list, rc);
 231
 232    ret = EXIT_SUCCESS;
 233 out:
 234    object_unref(OBJECT(sioc));
 235    return ret;
 236}
 237
 238
 239#if HAVE_NBD_DEVICE
 240static void *show_parts(void *arg)
 241{
 242    char *device = arg;
 243    int nbd;
 244
 245    /* linux just needs an open() to trigger
 246     * the partition table update
 247     * but remember to load the module with max_part != 0 :
 248     *     modprobe nbd max_part=63
 249     */
 250    nbd = open(device, O_RDWR);
 251    if (nbd >= 0) {
 252        close(nbd);
 253    }
 254    return NULL;
 255}
 256
 257static void *nbd_client_thread(void *arg)
 258{
 259    char *device = arg;
 260    NBDExportInfo info = { .request_sizes = false, .name = g_strdup("") };
 261    QIOChannelSocket *sioc;
 262    int fd;
 263    int ret;
 264    pthread_t show_parts_thread;
 265    Error *local_error = NULL;
 266
 267    sioc = qio_channel_socket_new();
 268    if (qio_channel_socket_connect_sync(sioc,
 269                                        saddr,
 270                                        &local_error) < 0) {
 271        error_report_err(local_error);
 272        goto out;
 273    }
 274
 275    ret = nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
 276                                NULL, NULL, NULL, &info, &local_error);
 277    if (ret < 0) {
 278        if (local_error) {
 279            error_report_err(local_error);
 280        }
 281        goto out_socket;
 282    }
 283
 284    fd = open(device, O_RDWR);
 285    if (fd < 0) {
 286        /* Linux-only, we can use %m in printf.  */
 287        error_report("Failed to open %s: %m", device);
 288        goto out_socket;
 289    }
 290
 291    ret = nbd_init(fd, sioc, &info, &local_error);
 292    if (ret < 0) {
 293        error_report_err(local_error);
 294        goto out_fd;
 295    }
 296
 297    /* update partition table */
 298    pthread_create(&show_parts_thread, NULL, show_parts, device);
 299
 300    if (verbose) {
 301        fprintf(stderr, "NBD device %s is now connected to %s\n",
 302                device, srcpath);
 303    } else {
 304        /* Close stderr so that the qemu-nbd process exits.  */
 305        dup2(STDOUT_FILENO, STDERR_FILENO);
 306    }
 307
 308    ret = nbd_client(fd);
 309    if (ret) {
 310        goto out_fd;
 311    }
 312    close(fd);
 313    object_unref(OBJECT(sioc));
 314    g_free(info.name);
 315    kill(getpid(), SIGTERM);
 316    return (void *) EXIT_SUCCESS;
 317
 318out_fd:
 319    close(fd);
 320out_socket:
 321    object_unref(OBJECT(sioc));
 322out:
 323    g_free(info.name);
 324    kill(getpid(), SIGTERM);
 325    return (void *) EXIT_FAILURE;
 326}
 327#endif /* HAVE_NBD_DEVICE */
 328
 329static int nbd_can_accept(void)
 330{
 331    return state == RUNNING && nb_fds < shared;
 332}
 333
 334static void nbd_export_closed(NBDExport *export)
 335{
 336    assert(state == TERMINATING);
 337    state = TERMINATED;
 338}
 339
 340static void nbd_update_server_watch(void);
 341
 342static void nbd_client_closed(NBDClient *client, bool negotiated)
 343{
 344    nb_fds--;
 345    if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
 346        state = TERMINATE;
 347    }
 348    nbd_update_server_watch();
 349    nbd_client_put(client);
 350}
 351
 352static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
 353                       gpointer opaque)
 354{
 355    if (state >= TERMINATE) {
 356        return;
 357    }
 358
 359    nb_fds++;
 360    nbd_update_server_watch();
 361    nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
 362}
 363
 364static void nbd_update_server_watch(void)
 365{
 366    if (nbd_can_accept()) {
 367        qio_net_listener_set_client_func(server, nbd_accept, NULL, NULL);
 368    } else {
 369        qio_net_listener_set_client_func(server, NULL, NULL, NULL);
 370    }
 371}
 372
 373
 374static SocketAddress *nbd_build_socket_address(const char *sockpath,
 375                                               const char *bindto,
 376                                               const char *port)
 377{
 378    SocketAddress *saddr;
 379
 380    saddr = g_new0(SocketAddress, 1);
 381    if (sockpath) {
 382        saddr->type = SOCKET_ADDRESS_TYPE_UNIX;
 383        saddr->u.q_unix.path = g_strdup(sockpath);
 384    } else {
 385        InetSocketAddress *inet;
 386        saddr->type = SOCKET_ADDRESS_TYPE_INET;
 387        inet = &saddr->u.inet;
 388        inet->host = g_strdup(bindto);
 389        if (port) {
 390            inet->port = g_strdup(port);
 391        } else  {
 392            inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 393        }
 394    }
 395
 396    return saddr;
 397}
 398
 399
 400static QemuOptsList file_opts = {
 401    .name = "file",
 402    .implied_opt_name = "file",
 403    .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 404    .desc = {
 405        /* no elements => accept any params */
 406        { /* end of list */ }
 407    },
 408};
 409
 410static QemuOptsList qemu_object_opts = {
 411    .name = "object",
 412    .implied_opt_name = "qom-type",
 413    .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 414    .desc = {
 415        { }
 416    },
 417};
 418
 419static bool qemu_nbd_object_print_help(const char *type, QemuOpts *opts)
 420{
 421    if (user_creatable_print_help(type, opts)) {
 422        exit(0);
 423    }
 424    return true;
 425}
 426
 427
 428static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list,
 429                                          Error **errp)
 430{
 431    Object *obj;
 432    QCryptoTLSCreds *creds;
 433
 434    obj = object_resolve_path_component(
 435        object_get_objects_root(), id);
 436    if (!obj) {
 437        error_setg(errp, "No TLS credentials with id '%s'",
 438                   id);
 439        return NULL;
 440    }
 441    creds = (QCryptoTLSCreds *)
 442        object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 443    if (!creds) {
 444        error_setg(errp, "Object with id '%s' is not TLS credentials",
 445                   id);
 446        return NULL;
 447    }
 448
 449    if (list) {
 450        if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
 451            error_setg(errp,
 452                       "Expecting TLS credentials with a client endpoint");
 453            return NULL;
 454        }
 455    } else {
 456        if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
 457            error_setg(errp,
 458                       "Expecting TLS credentials with a server endpoint");
 459            return NULL;
 460        }
 461    }
 462    object_ref(obj);
 463    return creds;
 464}
 465
 466static void setup_address_and_port(const char **address, const char **port)
 467{
 468    if (*address == NULL) {
 469        *address = "0.0.0.0";
 470    }
 471
 472    if (*port == NULL) {
 473        *port = stringify(NBD_DEFAULT_PORT);
 474    }
 475}
 476
 477/*
 478 * Check socket parameters compatibility when socket activation is used.
 479 */
 480static const char *socket_activation_validate_opts(const char *device,
 481                                                   const char *sockpath,
 482                                                   const char *address,
 483                                                   const char *port,
 484                                                   bool list)
 485{
 486    if (device != NULL) {
 487        return "NBD device can't be set when using socket activation";
 488    }
 489
 490    if (sockpath != NULL) {
 491        return "Unix socket can't be set when using socket activation";
 492    }
 493
 494    if (address != NULL) {
 495        return "The interface can't be set when using socket activation";
 496    }
 497
 498    if (port != NULL) {
 499        return "TCP port number can't be set when using socket activation";
 500    }
 501
 502    if (list) {
 503        return "List mode is incompatible with socket activation";
 504    }
 505
 506    return NULL;
 507}
 508
 509static void qemu_nbd_shutdown(void)
 510{
 511    job_cancel_sync_all();
 512    bdrv_close_all();
 513}
 514
 515int main(int argc, char **argv)
 516{
 517    BlockBackend *blk;
 518    BlockDriverState *bs;
 519    uint64_t dev_offset = 0;
 520    bool readonly = false;
 521    bool disconnect = false;
 522    const char *bindto = NULL;
 523    const char *port = NULL;
 524    char *sockpath = NULL;
 525    char *device = NULL;
 526    int64_t fd_size;
 527    QemuOpts *sn_opts = NULL;
 528    const char *sn_id_or_name = NULL;
 529    const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:B:L";
 530    struct option lopt[] = {
 531        { "help", no_argument, NULL, 'h' },
 532        { "version", no_argument, NULL, 'V' },
 533        { "bind", required_argument, NULL, 'b' },
 534        { "port", required_argument, NULL, 'p' },
 535        { "socket", required_argument, NULL, 'k' },
 536        { "offset", required_argument, NULL, 'o' },
 537        { "read-only", no_argument, NULL, 'r' },
 538        { "bitmap", required_argument, NULL, 'B' },
 539        { "connect", required_argument, NULL, 'c' },
 540        { "disconnect", no_argument, NULL, 'd' },
 541        { "list", no_argument, NULL, 'L' },
 542        { "snapshot", no_argument, NULL, 's' },
 543        { "load-snapshot", required_argument, NULL, 'l' },
 544        { "nocache", no_argument, NULL, 'n' },
 545        { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 546        { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 547        { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 548        { "detect-zeroes", required_argument, NULL,
 549          QEMU_NBD_OPT_DETECT_ZEROES },
 550        { "shared", required_argument, NULL, 'e' },
 551        { "format", required_argument, NULL, 'f' },
 552        { "persistent", no_argument, NULL, 't' },
 553        { "verbose", no_argument, NULL, 'v' },
 554        { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 555        { "export-name", required_argument, NULL, 'x' },
 556        { "description", required_argument, NULL, 'D' },
 557        { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 558        { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
 559        { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 560        { "trace", required_argument, NULL, 'T' },
 561        { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
 562        { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE },
 563        { NULL, 0, NULL, 0 }
 564    };
 565    int ch;
 566    int opt_ind = 0;
 567    int flags = BDRV_O_RDWR;
 568    int ret = 0;
 569    bool seen_cache = false;
 570    bool seen_discard = false;
 571    bool seen_aio = false;
 572    pthread_t client_thread;
 573    const char *fmt = NULL;
 574    Error *local_err = NULL;
 575    BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 576    QDict *options = NULL;
 577    const char *export_name = NULL; /* defaults to "" later for server mode */
 578    const char *export_description = NULL;
 579    const char *bitmap = NULL;
 580    const char *tlscredsid = NULL;
 581    bool imageOpts = false;
 582    bool writethrough = true;
 583    char *trace_file = NULL;
 584    bool fork_process = false;
 585    bool list = false;
 586    int old_stderr = -1;
 587    unsigned socket_activation;
 588    const char *pid_file_name = NULL;
 589
 590    /* The client thread uses SIGTERM to interrupt the server.  A signal
 591     * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 592     */
 593    struct sigaction sa_sigterm;
 594    memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 595    sa_sigterm.sa_handler = termsig_handler;
 596    sigaction(SIGTERM, &sa_sigterm, NULL);
 597
 598#ifdef CONFIG_POSIX
 599    signal(SIGPIPE, SIG_IGN);
 600#endif
 601
 602    error_init(argv[0]);
 603    module_call_init(MODULE_INIT_TRACE);
 604    qcrypto_init(&error_fatal);
 605
 606    module_call_init(MODULE_INIT_QOM);
 607    qemu_add_opts(&qemu_object_opts);
 608    qemu_add_opts(&qemu_trace_opts);
 609    qemu_init_exec_dir(argv[0]);
 610
 611    while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 612        switch (ch) {
 613        case 's':
 614            flags |= BDRV_O_SNAPSHOT;
 615            break;
 616        case 'n':
 617            optarg = (char *) "none";
 618            /* fallthrough */
 619        case QEMU_NBD_OPT_CACHE:
 620            if (seen_cache) {
 621                error_report("-n and --cache can only be specified once");
 622                exit(EXIT_FAILURE);
 623            }
 624            seen_cache = true;
 625            if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 626                error_report("Invalid cache mode `%s'", optarg);
 627                exit(EXIT_FAILURE);
 628            }
 629            break;
 630        case QEMU_NBD_OPT_AIO:
 631            if (seen_aio) {
 632                error_report("--aio can only be specified once");
 633                exit(EXIT_FAILURE);
 634            }
 635            seen_aio = true;
 636            if (bdrv_parse_aio(optarg, &flags) < 0) {
 637                error_report("Invalid aio mode '%s'", optarg);
 638                exit(EXIT_FAILURE);
 639            }
 640            break;
 641        case QEMU_NBD_OPT_DISCARD:
 642            if (seen_discard) {
 643                error_report("--discard can only be specified once");
 644                exit(EXIT_FAILURE);
 645            }
 646            seen_discard = true;
 647            if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 648                error_report("Invalid discard mode `%s'", optarg);
 649                exit(EXIT_FAILURE);
 650            }
 651            break;
 652        case QEMU_NBD_OPT_DETECT_ZEROES:
 653            detect_zeroes =
 654                qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
 655                                optarg,
 656                                BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 657                                &local_err);
 658            if (local_err) {
 659                error_reportf_err(local_err,
 660                                  "Failed to parse detect_zeroes mode: ");
 661                exit(EXIT_FAILURE);
 662            }
 663            if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 664                !(flags & BDRV_O_UNMAP)) {
 665                error_report("setting detect-zeroes to unmap is not allowed "
 666                             "without setting discard operation to unmap");
 667                exit(EXIT_FAILURE);
 668            }
 669            break;
 670        case 'b':
 671            bindto = optarg;
 672            break;
 673        case 'p':
 674            port = optarg;
 675            break;
 676        case 'o':
 677            if (qemu_strtou64(optarg, NULL, 0, &dev_offset) < 0) {
 678                error_report("Invalid offset '%s'", optarg);
 679                exit(EXIT_FAILURE);
 680            }
 681            break;
 682        case 'l':
 683            if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 684                sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 685                                                  optarg, false);
 686                if (!sn_opts) {
 687                    error_report("Failed in parsing snapshot param `%s'",
 688                                 optarg);
 689                    exit(EXIT_FAILURE);
 690                }
 691            } else {
 692                sn_id_or_name = optarg;
 693            }
 694            /* fall through */
 695        case 'r':
 696            readonly = true;
 697            flags &= ~BDRV_O_RDWR;
 698            break;
 699        case 'B':
 700            bitmap = optarg;
 701            break;
 702        case 'k':
 703            sockpath = optarg;
 704            if (sockpath[0] != '/') {
 705                error_report("socket path must be absolute");
 706                exit(EXIT_FAILURE);
 707            }
 708            break;
 709        case 'd':
 710            disconnect = true;
 711            break;
 712        case 'c':
 713            device = optarg;
 714            break;
 715        case 'e':
 716            if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
 717                shared < 1) {
 718                error_report("Invalid shared device number '%s'", optarg);
 719                exit(EXIT_FAILURE);
 720            }
 721            break;
 722        case 'f':
 723            fmt = optarg;
 724            break;
 725        case 't':
 726            persistent = 1;
 727            break;
 728        case 'x':
 729            export_name = optarg;
 730            if (strlen(export_name) > NBD_MAX_STRING_SIZE) {
 731                error_report("export name '%s' too long", export_name);
 732                exit(EXIT_FAILURE);
 733            }
 734            break;
 735        case 'D':
 736            export_description = optarg;
 737            if (strlen(export_description) > NBD_MAX_STRING_SIZE) {
 738                error_report("export description '%s' too long",
 739                             export_description);
 740                exit(EXIT_FAILURE);
 741            }
 742            break;
 743        case 'v':
 744            verbose = 1;
 745            break;
 746        case 'V':
 747            version(argv[0]);
 748            exit(0);
 749            break;
 750        case 'h':
 751            usage(argv[0]);
 752            exit(0);
 753            break;
 754        case '?':
 755            error_report("Try `%s --help' for more information.", argv[0]);
 756            exit(EXIT_FAILURE);
 757        case QEMU_NBD_OPT_OBJECT: {
 758            QemuOpts *opts;
 759            opts = qemu_opts_parse_noisily(&qemu_object_opts,
 760                                           optarg, true);
 761            if (!opts) {
 762                exit(EXIT_FAILURE);
 763            }
 764        }   break;
 765        case QEMU_NBD_OPT_TLSCREDS:
 766            tlscredsid = optarg;
 767            break;
 768        case QEMU_NBD_OPT_IMAGE_OPTS:
 769            imageOpts = true;
 770            break;
 771        case 'T':
 772            g_free(trace_file);
 773            trace_file = trace_opt_parse(optarg);
 774            break;
 775        case QEMU_NBD_OPT_TLSAUTHZ:
 776            tlsauthz = optarg;
 777            break;
 778        case QEMU_NBD_OPT_FORK:
 779            fork_process = true;
 780            break;
 781        case 'L':
 782            list = true;
 783            break;
 784        case QEMU_NBD_OPT_PID_FILE:
 785            pid_file_name = optarg;
 786            break;
 787        }
 788    }
 789
 790    if (list) {
 791        if (argc != optind) {
 792            error_report("List mode is incompatible with a file name");
 793            exit(EXIT_FAILURE);
 794        }
 795        if (export_name || export_description || dev_offset ||
 796            device || disconnect || fmt || sn_id_or_name || bitmap ||
 797            seen_aio || seen_discard || seen_cache) {
 798            error_report("List mode is incompatible with per-device settings");
 799            exit(EXIT_FAILURE);
 800        }
 801        if (fork_process) {
 802            error_report("List mode is incompatible with forking");
 803            exit(EXIT_FAILURE);
 804        }
 805    } else if ((argc - optind) != 1) {
 806        error_report("Invalid number of arguments");
 807        error_printf("Try `%s --help' for more information.\n", argv[0]);
 808        exit(EXIT_FAILURE);
 809    } else if (!export_name) {
 810        export_name = "";
 811    }
 812
 813    qemu_opts_foreach(&qemu_object_opts,
 814                      user_creatable_add_opts_foreach,
 815                      qemu_nbd_object_print_help, &error_fatal);
 816
 817    if (!trace_init_backends()) {
 818        exit(1);
 819    }
 820    trace_init_file(trace_file);
 821    qemu_set_log(LOG_TRACE);
 822
 823    socket_activation = check_socket_activation();
 824    if (socket_activation == 0) {
 825        setup_address_and_port(&bindto, &port);
 826    } else {
 827        /* Using socket activation - check user didn't use -p etc. */
 828        const char *err_msg = socket_activation_validate_opts(device, sockpath,
 829                                                              bindto, port,
 830                                                              list);
 831        if (err_msg != NULL) {
 832            error_report("%s", err_msg);
 833            exit(EXIT_FAILURE);
 834        }
 835
 836        /* qemu-nbd can only listen on a single socket.  */
 837        if (socket_activation > 1) {
 838            error_report("qemu-nbd does not support socket activation with %s > 1",
 839                         "LISTEN_FDS");
 840            exit(EXIT_FAILURE);
 841        }
 842    }
 843
 844    if (tlscredsid) {
 845        if (sockpath) {
 846            error_report("TLS is only supported with IPv4/IPv6");
 847            exit(EXIT_FAILURE);
 848        }
 849        if (device) {
 850            error_report("TLS is not supported with a host device");
 851            exit(EXIT_FAILURE);
 852        }
 853        if (tlsauthz && list) {
 854            error_report("TLS authorization is incompatible with export list");
 855            exit(EXIT_FAILURE);
 856        }
 857        tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
 858        if (local_err) {
 859            error_report("Failed to get TLS creds %s",
 860                         error_get_pretty(local_err));
 861            exit(EXIT_FAILURE);
 862        }
 863    } else {
 864        if (tlsauthz) {
 865            error_report("--tls-authz is not permitted without --tls-creds");
 866            exit(EXIT_FAILURE);
 867        }
 868    }
 869
 870    if (list) {
 871        saddr = nbd_build_socket_address(sockpath, bindto, port);
 872        return qemu_nbd_client_list(saddr, tlscreds, bindto);
 873    }
 874
 875#if !HAVE_NBD_DEVICE
 876    if (disconnect || device) {
 877        error_report("Kernel /dev/nbdN support not available");
 878        exit(EXIT_FAILURE);
 879    }
 880#else /* HAVE_NBD_DEVICE */
 881    if (disconnect) {
 882        int nbdfd = open(argv[optind], O_RDWR);
 883        if (nbdfd < 0) {
 884            error_report("Cannot open %s: %s", argv[optind],
 885                         strerror(errno));
 886            exit(EXIT_FAILURE);
 887        }
 888        nbd_disconnect(nbdfd);
 889
 890        close(nbdfd);
 891
 892        printf("%s disconnected\n", argv[optind]);
 893
 894        return 0;
 895    }
 896#endif
 897
 898    if ((device && !verbose) || fork_process) {
 899        int stderr_fd[2];
 900        pid_t pid;
 901        int ret;
 902
 903        if (qemu_pipe(stderr_fd) < 0) {
 904            error_report("Error setting up communication pipe: %s",
 905                         strerror(errno));
 906            exit(EXIT_FAILURE);
 907        }
 908
 909        /* Now daemonize, but keep a communication channel open to
 910         * print errors and exit with the proper status code.
 911         */
 912        pid = fork();
 913        if (pid < 0) {
 914            error_report("Failed to fork: %s", strerror(errno));
 915            exit(EXIT_FAILURE);
 916        } else if (pid == 0) {
 917            close(stderr_fd[0]);
 918
 919            old_stderr = dup(STDERR_FILENO);
 920            ret = qemu_daemon(1, 0);
 921
 922            /* Temporarily redirect stderr to the parent's pipe...  */
 923            dup2(stderr_fd[1], STDERR_FILENO);
 924            if (ret < 0) {
 925                error_report("Failed to daemonize: %s", strerror(errno));
 926                exit(EXIT_FAILURE);
 927            }
 928
 929            /* ... close the descriptor we inherited and go on.  */
 930            close(stderr_fd[1]);
 931        } else {
 932            bool errors = false;
 933            char *buf;
 934
 935            /* In the parent.  Print error messages from the child until
 936             * it closes the pipe.
 937             */
 938            close(stderr_fd[1]);
 939            buf = g_malloc(1024);
 940            while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 941                errors = true;
 942                ret = qemu_write_full(STDERR_FILENO, buf, ret);
 943                if (ret < 0) {
 944                    exit(EXIT_FAILURE);
 945                }
 946            }
 947            if (ret < 0) {
 948                error_report("Cannot read from daemon: %s",
 949                             strerror(errno));
 950                exit(EXIT_FAILURE);
 951            }
 952
 953            /* Usually the daemon should not print any message.
 954             * Exit with zero status in that case.
 955             */
 956            exit(errors);
 957        }
 958    }
 959
 960    if (device != NULL && sockpath == NULL) {
 961        sockpath = g_malloc(128);
 962        snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 963    }
 964
 965    server = qio_net_listener_new();
 966    if (socket_activation == 0) {
 967        saddr = nbd_build_socket_address(sockpath, bindto, port);
 968        if (qio_net_listener_open_sync(server, saddr, 1, &local_err) < 0) {
 969            object_unref(OBJECT(server));
 970            error_report_err(local_err);
 971            exit(EXIT_FAILURE);
 972        }
 973    } else {
 974        size_t i;
 975        /* See comment in check_socket_activation above. */
 976        for (i = 0; i < socket_activation; i++) {
 977            QIOChannelSocket *sioc;
 978            sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
 979                                             &local_err);
 980            if (sioc == NULL) {
 981                object_unref(OBJECT(server));
 982                error_report("Failed to use socket activation: %s",
 983                             error_get_pretty(local_err));
 984                exit(EXIT_FAILURE);
 985            }
 986            qio_net_listener_add(server, sioc);
 987            object_unref(OBJECT(sioc));
 988        }
 989    }
 990
 991    if (qemu_init_main_loop(&local_err)) {
 992        error_report_err(local_err);
 993        exit(EXIT_FAILURE);
 994    }
 995    bdrv_init();
 996    atexit(qemu_nbd_shutdown);
 997
 998    srcpath = argv[optind];
 999    if (imageOpts) {
1000        QemuOpts *opts;
1001        if (fmt) {
1002            error_report("--image-opts and -f are mutually exclusive");
1003            exit(EXIT_FAILURE);
1004        }
1005        opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
1006        if (!opts) {
1007            qemu_opts_reset(&file_opts);
1008            exit(EXIT_FAILURE);
1009        }
1010        options = qemu_opts_to_qdict(opts, NULL);
1011        qemu_opts_reset(&file_opts);
1012        blk = blk_new_open(NULL, NULL, options, flags, &local_err);
1013    } else {
1014        if (fmt) {
1015            options = qdict_new();
1016            qdict_put_str(options, "driver", fmt);
1017        }
1018        blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
1019    }
1020
1021    if (!blk) {
1022        error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
1023                          argv[optind]);
1024        exit(EXIT_FAILURE);
1025    }
1026    bs = blk_bs(blk);
1027
1028    blk_set_enable_write_cache(blk, !writethrough);
1029
1030    if (sn_opts) {
1031        ret = bdrv_snapshot_load_tmp(bs,
1032                                     qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
1033                                     qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
1034                                     &local_err);
1035    } else if (sn_id_or_name) {
1036        ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
1037                                                   &local_err);
1038    }
1039    if (ret < 0) {
1040        error_reportf_err(local_err, "Failed to load snapshot: ");
1041        exit(EXIT_FAILURE);
1042    }
1043
1044    bs->detect_zeroes = detect_zeroes;
1045    fd_size = blk_getlength(blk);
1046    if (fd_size < 0) {
1047        error_report("Failed to determine the image length: %s",
1048                     strerror(-fd_size));
1049        exit(EXIT_FAILURE);
1050    }
1051
1052    if (dev_offset >= fd_size) {
1053        error_report("Offset (%" PRIu64 ") has to be smaller than the image "
1054                     "size (%" PRId64 ")", dev_offset, fd_size);
1055        exit(EXIT_FAILURE);
1056    }
1057    fd_size -= dev_offset;
1058
1059    export = nbd_export_new(bs, dev_offset, fd_size, export_name,
1060                            export_description, bitmap, readonly, shared > 1,
1061                            nbd_export_closed, writethrough, NULL,
1062                            &error_fatal);
1063
1064    if (device) {
1065#if HAVE_NBD_DEVICE
1066        int ret;
1067
1068        ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1069        if (ret != 0) {
1070            error_report("Failed to create client thread: %s", strerror(ret));
1071            exit(EXIT_FAILURE);
1072        }
1073#endif
1074    } else {
1075        /* Shut up GCC warnings.  */
1076        memset(&client_thread, 0, sizeof(client_thread));
1077    }
1078
1079    nbd_update_server_watch();
1080
1081    if (pid_file_name) {
1082        qemu_write_pidfile(pid_file_name, &error_fatal);
1083    }
1084
1085    /* now when the initialization is (almost) complete, chdir("/")
1086     * to free any busy filesystems */
1087    if (chdir("/") < 0) {
1088        error_report("Could not chdir to root directory: %s",
1089                     strerror(errno));
1090        exit(EXIT_FAILURE);
1091    }
1092
1093    if (fork_process) {
1094        dup2(old_stderr, STDERR_FILENO);
1095        close(old_stderr);
1096    }
1097
1098    state = RUNNING;
1099    do {
1100        main_loop_wait(false);
1101        if (state == TERMINATE) {
1102            state = TERMINATING;
1103            nbd_export_close(export);
1104            nbd_export_put(export);
1105            export = NULL;
1106        }
1107    } while (state != TERMINATED);
1108
1109    blk_unref(blk);
1110    if (sockpath) {
1111        unlink(sockpath);
1112    }
1113
1114    qemu_opts_del(sn_opts);
1115
1116    if (device) {
1117        void *ret;
1118        pthread_join(client_thread, &ret);
1119        exit(ret != NULL);
1120    } else {
1121        exit(EXIT_SUCCESS);
1122    }
1123}
1124