qemu/qemu-nbd.c
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   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-common.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/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/qstring.h"
  38#include "qom/object_interfaces.h"
  39#include "io/channel-socket.h"
  40#include "crypto/init.h"
  41#include "trace/control.h"
  42#include "qemu-version.h"
  43
  44#define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
  45#define QEMU_NBD_OPT_CACHE         256
  46#define QEMU_NBD_OPT_AIO           257
  47#define QEMU_NBD_OPT_DISCARD       258
  48#define QEMU_NBD_OPT_DETECT_ZEROES 259
  49#define QEMU_NBD_OPT_OBJECT        260
  50#define QEMU_NBD_OPT_TLSCREDS      261
  51#define QEMU_NBD_OPT_IMAGE_OPTS    262
  52#define QEMU_NBD_OPT_FORK          263
  53
  54#define MBR_SIZE 512
  55
  56static NBDExport *exp;
  57static bool newproto;
  58static int verbose;
  59static char *srcpath;
  60static SocketAddress *saddr;
  61static int persistent = 0;
  62static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
  63static int shared = 1;
  64static int nb_fds;
  65static QIOChannelSocket *server_ioc;
  66static int server_watch = -1;
  67static QCryptoTLSCreds *tlscreds;
  68
  69static void usage(const char *name)
  70{
  71    (printf) (
  72"Usage: %s [OPTIONS] FILE\n"
  73"QEMU Disk Network Block Device Server\n"
  74"\n"
  75"  -h, --help                display this help and exit\n"
  76"  -V, --version             output version information and exit\n"
  77"\n"
  78"Connection properties:\n"
  79"  -p, --port=PORT           port to listen on (default `%d')\n"
  80"  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
  81"  -k, --socket=PATH         path to the unix socket\n"
  82"                            (default '"SOCKET_PATH"')\n"
  83"  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"
  84"  -t, --persistent          don't exit on the last connection\n"
  85"  -v, --verbose             display extra debugging information\n"
  86"  -x, --export-name=NAME    expose export by name\n"
  87"  -D, --description=TEXT    with -x, also export a human-readable description\n"
  88"\n"
  89"Exposing part of the image:\n"
  90"  -o, --offset=OFFSET       offset into the image\n"
  91"  -P, --partition=NUM       only expose partition NUM\n"
  92"\n"
  93"General purpose options:\n"
  94"  --object type,id=ID,...   define an object such as 'secret' for providing\n"
  95"                            passwords and/or encryption keys\n"
  96"  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
  97"                            specify tracing options\n"
  98"  --fork                    fork off the server process and exit the parent\n"
  99"                            once the server is running\n"
 100#ifdef __linux__
 101"Kernel NBD client support:\n"
 102"  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
 103"  -d, --disconnect          disconnect the specified device\n"
 104"\n"
 105#endif
 106"\n"
 107"Block device options:\n"
 108"  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
 109"  -r, --read-only           export read-only\n"
 110"  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
 111"                            file with backing_file=FILE, redirect the write to\n"
 112"                            the temporary one\n"
 113"  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 114"                            load an internal snapshot inside FILE and export it\n"
 115"                            as an read-only device, SNAPSHOT_PARAM format is\n"
 116"                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 117"                            '[ID_OR_NAME]'\n"
 118"  -n, --nocache             disable host cache\n"
 119"      --cache=MODE          set cache mode (none, writeback, ...)\n"
 120"      --aio=MODE            set AIO mode (native or threads)\n"
 121"      --discard=MODE        set discard mode (ignore, unmap)\n"
 122"      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 123"      --image-opts          treat FILE as a full set of image options\n"
 124"\n"
 125QEMU_HELP_BOTTOM "\n"
 126    , name, NBD_DEFAULT_PORT, "DEVICE");
 127}
 128
 129static void version(const char *name)
 130{
 131    printf(
 132"%s " QEMU_VERSION QEMU_PKGVERSION "\n"
 133"Written by Anthony Liguori.\n"
 134"\n"
 135QEMU_COPYRIGHT "\n"
 136"This is free software; see the source for copying conditions.  There is NO\n"
 137"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 138    , name);
 139}
 140
 141struct partition_record
 142{
 143    uint8_t bootable;
 144    uint8_t start_head;
 145    uint32_t start_cylinder;
 146    uint8_t start_sector;
 147    uint8_t system;
 148    uint8_t end_head;
 149    uint8_t end_cylinder;
 150    uint8_t end_sector;
 151    uint32_t start_sector_abs;
 152    uint32_t nb_sectors_abs;
 153};
 154
 155static void read_partition(uint8_t *p, struct partition_record *r)
 156{
 157    r->bootable = p[0];
 158    r->start_head = p[1];
 159    r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 160    r->start_sector = p[2] & 0x3f;
 161    r->system = p[4];
 162    r->end_head = p[5];
 163    r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 164    r->end_sector = p[6] & 0x3f;
 165
 166    r->start_sector_abs = ldl_le_p(p + 8);
 167    r->nb_sectors_abs   = ldl_le_p(p + 12);
 168}
 169
 170static int find_partition(BlockBackend *blk, int partition,
 171                          off_t *offset, off_t *size)
 172{
 173    struct partition_record mbr[4];
 174    uint8_t data[MBR_SIZE];
 175    int i;
 176    int ext_partnum = 4;
 177    int ret;
 178
 179    ret = blk_pread(blk, 0, data, sizeof(data));
 180    if (ret < 0) {
 181        error_report("error while reading: %s", strerror(-ret));
 182        exit(EXIT_FAILURE);
 183    }
 184
 185    if (data[510] != 0x55 || data[511] != 0xaa) {
 186        return -EINVAL;
 187    }
 188
 189    for (i = 0; i < 4; i++) {
 190        read_partition(&data[446 + 16 * i], &mbr[i]);
 191
 192        if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
 193            continue;
 194        }
 195
 196        if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 197            struct partition_record ext[4];
 198            uint8_t data1[MBR_SIZE];
 199            int j;
 200
 201            ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE,
 202                            data1, sizeof(data1));
 203            if (ret < 0) {
 204                error_report("error while reading: %s", strerror(-ret));
 205                exit(EXIT_FAILURE);
 206            }
 207
 208            for (j = 0; j < 4; j++) {
 209                read_partition(&data1[446 + 16 * j], &ext[j]);
 210                if (!ext[j].system || !ext[j].nb_sectors_abs) {
 211                    continue;
 212                }
 213
 214                if ((ext_partnum + j + 1) == partition) {
 215                    *offset = (uint64_t)ext[j].start_sector_abs << 9;
 216                    *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 217                    return 0;
 218                }
 219            }
 220            ext_partnum += 4;
 221        } else if ((i + 1) == partition) {
 222            *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 223            *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 224            return 0;
 225        }
 226    }
 227
 228    return -ENOENT;
 229}
 230
 231static void termsig_handler(int signum)
 232{
 233    atomic_cmpxchg(&state, RUNNING, TERMINATE);
 234    qemu_notify_event();
 235}
 236
 237
 238static void *show_parts(void *arg)
 239{
 240    char *device = arg;
 241    int nbd;
 242
 243    /* linux just needs an open() to trigger
 244     * the partition table update
 245     * but remember to load the module with max_part != 0 :
 246     *     modprobe nbd max_part=63
 247     */
 248    nbd = open(device, O_RDWR);
 249    if (nbd >= 0) {
 250        close(nbd);
 251    }
 252    return NULL;
 253}
 254
 255static void *nbd_client_thread(void *arg)
 256{
 257    char *device = arg;
 258    NBDExportInfo info = { .request_sizes = false, };
 259    QIOChannelSocket *sioc;
 260    int fd;
 261    int ret;
 262    pthread_t show_parts_thread;
 263    Error *local_error = NULL;
 264
 265    sioc = qio_channel_socket_new();
 266    if (qio_channel_socket_connect_sync(sioc,
 267                                        saddr,
 268                                        &local_error) < 0) {
 269        error_report_err(local_error);
 270        goto out;
 271    }
 272
 273    ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), NULL,
 274                                NULL, NULL, NULL, &info, &local_error);
 275    if (ret < 0) {
 276        if (local_error) {
 277            error_report_err(local_error);
 278        }
 279        goto out_socket;
 280    }
 281
 282    fd = open(device, O_RDWR);
 283    if (fd < 0) {
 284        /* Linux-only, we can use %m in printf.  */
 285        error_report("Failed to open %s: %m", device);
 286        goto out_socket;
 287    }
 288
 289    ret = nbd_init(fd, sioc, &info, &local_error);
 290    if (ret < 0) {
 291        error_report_err(local_error);
 292        goto out_fd;
 293    }
 294
 295    /* update partition table */
 296    pthread_create(&show_parts_thread, NULL, show_parts, device);
 297
 298    if (verbose) {
 299        fprintf(stderr, "NBD device %s is now connected to %s\n",
 300                device, srcpath);
 301    } else {
 302        /* Close stderr so that the qemu-nbd process exits.  */
 303        dup2(STDOUT_FILENO, STDERR_FILENO);
 304    }
 305
 306    ret = nbd_client(fd);
 307    if (ret) {
 308        goto out_fd;
 309    }
 310    close(fd);
 311    object_unref(OBJECT(sioc));
 312    kill(getpid(), SIGTERM);
 313    return (void *) EXIT_SUCCESS;
 314
 315out_fd:
 316    close(fd);
 317out_socket:
 318    object_unref(OBJECT(sioc));
 319out:
 320    kill(getpid(), SIGTERM);
 321    return (void *) EXIT_FAILURE;
 322}
 323
 324static int nbd_can_accept(void)
 325{
 326    return state == RUNNING && nb_fds < shared;
 327}
 328
 329static void nbd_export_closed(NBDExport *exp)
 330{
 331    assert(state == TERMINATING);
 332    state = TERMINATED;
 333}
 334
 335static void nbd_update_server_watch(void);
 336
 337static void nbd_client_closed(NBDClient *client, bool negotiated)
 338{
 339    nb_fds--;
 340    if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
 341        state = TERMINATE;
 342    }
 343    nbd_update_server_watch();
 344    nbd_client_put(client);
 345}
 346
 347static gboolean nbd_accept(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
 348{
 349    QIOChannelSocket *cioc;
 350
 351    cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
 352                                     NULL);
 353    if (!cioc) {
 354        return TRUE;
 355    }
 356
 357    if (state >= TERMINATE) {
 358        object_unref(OBJECT(cioc));
 359        return TRUE;
 360    }
 361
 362    nb_fds++;
 363    nbd_update_server_watch();
 364    nbd_client_new(newproto ? NULL : exp, cioc,
 365                   tlscreds, NULL, nbd_client_closed);
 366    object_unref(OBJECT(cioc));
 367
 368    return TRUE;
 369}
 370
 371static void nbd_update_server_watch(void)
 372{
 373    if (nbd_can_accept()) {
 374        if (server_watch == -1) {
 375            server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
 376                                                 G_IO_IN,
 377                                                 nbd_accept,
 378                                                 NULL, NULL);
 379        }
 380    } else {
 381        if (server_watch != -1) {
 382            g_source_remove(server_watch);
 383            server_watch = -1;
 384        }
 385    }
 386}
 387
 388
 389static SocketAddress *nbd_build_socket_address(const char *sockpath,
 390                                               const char *bindto,
 391                                               const char *port)
 392{
 393    SocketAddress *saddr;
 394
 395    saddr = g_new0(SocketAddress, 1);
 396    if (sockpath) {
 397        saddr->type = SOCKET_ADDRESS_TYPE_UNIX;
 398        saddr->u.q_unix.path = g_strdup(sockpath);
 399    } else {
 400        InetSocketAddress *inet;
 401        saddr->type = SOCKET_ADDRESS_TYPE_INET;
 402        inet = &saddr->u.inet;
 403        inet->host = g_strdup(bindto);
 404        if (port) {
 405            inet->port = g_strdup(port);
 406        } else  {
 407            inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 408        }
 409    }
 410
 411    return saddr;
 412}
 413
 414
 415static QemuOptsList file_opts = {
 416    .name = "file",
 417    .implied_opt_name = "file",
 418    .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 419    .desc = {
 420        /* no elements => accept any params */
 421        { /* end of list */ }
 422    },
 423};
 424
 425static QemuOptsList qemu_object_opts = {
 426    .name = "object",
 427    .implied_opt_name = "qom-type",
 428    .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 429    .desc = {
 430        { }
 431    },
 432};
 433
 434
 435
 436static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 437{
 438    Object *obj;
 439    QCryptoTLSCreds *creds;
 440
 441    obj = object_resolve_path_component(
 442        object_get_objects_root(), id);
 443    if (!obj) {
 444        error_setg(errp, "No TLS credentials with id '%s'",
 445                   id);
 446        return NULL;
 447    }
 448    creds = (QCryptoTLSCreds *)
 449        object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 450    if (!creds) {
 451        error_setg(errp, "Object with id '%s' is not TLS credentials",
 452                   id);
 453        return NULL;
 454    }
 455
 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    object_ref(obj);
 462    return creds;
 463}
 464
 465static void setup_address_and_port(const char **address, const char **port)
 466{
 467    if (*address == NULL) {
 468        *address = "0.0.0.0";
 469    }
 470
 471    if (*port == NULL) {
 472        *port = stringify(NBD_DEFAULT_PORT);
 473    }
 474}
 475
 476/*
 477 * Check socket parameters compatibility when socket activation is used.
 478 */
 479static const char *socket_activation_validate_opts(const char *device,
 480                                                   const char *sockpath,
 481                                                   const char *address,
 482                                                   const char *port)
 483{
 484    if (device != NULL) {
 485        return "NBD device can't be set when using socket activation";
 486    }
 487
 488    if (sockpath != NULL) {
 489        return "Unix socket can't be set when using socket activation";
 490    }
 491
 492    if (address != NULL) {
 493        return "The interface can't be set when using socket activation";
 494    }
 495
 496    if (port != NULL) {
 497        return "TCP port number can't be set when using socket activation";
 498    }
 499
 500    return NULL;
 501}
 502
 503int main(int argc, char **argv)
 504{
 505    BlockBackend *blk;
 506    BlockDriverState *bs;
 507    off_t dev_offset = 0;
 508    uint16_t nbdflags = 0;
 509    bool disconnect = false;
 510    const char *bindto = NULL;
 511    const char *port = NULL;
 512    char *sockpath = NULL;
 513    char *device = NULL;
 514    off_t fd_size;
 515    QemuOpts *sn_opts = NULL;
 516    const char *sn_id_or_name = NULL;
 517    const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:";
 518    struct option lopt[] = {
 519        { "help", no_argument, NULL, 'h' },
 520        { "version", no_argument, NULL, 'V' },
 521        { "bind", required_argument, NULL, 'b' },
 522        { "port", required_argument, NULL, 'p' },
 523        { "socket", required_argument, NULL, 'k' },
 524        { "offset", required_argument, NULL, 'o' },
 525        { "read-only", no_argument, NULL, 'r' },
 526        { "partition", required_argument, NULL, 'P' },
 527        { "connect", required_argument, NULL, 'c' },
 528        { "disconnect", no_argument, NULL, 'd' },
 529        { "snapshot", no_argument, NULL, 's' },
 530        { "load-snapshot", required_argument, NULL, 'l' },
 531        { "nocache", no_argument, NULL, 'n' },
 532        { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 533        { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 534        { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 535        { "detect-zeroes", required_argument, NULL,
 536          QEMU_NBD_OPT_DETECT_ZEROES },
 537        { "shared", required_argument, NULL, 'e' },
 538        { "format", required_argument, NULL, 'f' },
 539        { "persistent", no_argument, NULL, 't' },
 540        { "verbose", no_argument, NULL, 'v' },
 541        { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 542        { "export-name", required_argument, NULL, 'x' },
 543        { "description", required_argument, NULL, 'D' },
 544        { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 545        { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 546        { "trace", required_argument, NULL, 'T' },
 547        { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
 548        { NULL, 0, NULL, 0 }
 549    };
 550    int ch;
 551    int opt_ind = 0;
 552    char *end;
 553    int flags = BDRV_O_RDWR;
 554    int partition = -1;
 555    int ret = 0;
 556    bool seen_cache = false;
 557    bool seen_discard = false;
 558    bool seen_aio = false;
 559    pthread_t client_thread;
 560    const char *fmt = NULL;
 561    Error *local_err = NULL;
 562    BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 563    QDict *options = NULL;
 564    const char *export_name = NULL;
 565    const char *export_description = NULL;
 566    const char *tlscredsid = NULL;
 567    bool imageOpts = false;
 568    bool writethrough = true;
 569    char *trace_file = NULL;
 570    bool fork_process = false;
 571    int old_stderr = -1;
 572    unsigned socket_activation;
 573
 574    /* The client thread uses SIGTERM to interrupt the server.  A signal
 575     * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 576     */
 577    struct sigaction sa_sigterm;
 578    memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 579    sa_sigterm.sa_handler = termsig_handler;
 580    sigaction(SIGTERM, &sa_sigterm, NULL);
 581
 582#ifdef CONFIG_POSIX
 583    signal(SIGPIPE, SIG_IGN);
 584#endif
 585
 586    module_call_init(MODULE_INIT_TRACE);
 587    qcrypto_init(&error_fatal);
 588
 589    module_call_init(MODULE_INIT_QOM);
 590    qemu_add_opts(&qemu_object_opts);
 591    qemu_add_opts(&qemu_trace_opts);
 592    qemu_init_exec_dir(argv[0]);
 593
 594    while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 595        switch (ch) {
 596        case 's':
 597            flags |= BDRV_O_SNAPSHOT;
 598            break;
 599        case 'n':
 600            optarg = (char *) "none";
 601            /* fallthrough */
 602        case QEMU_NBD_OPT_CACHE:
 603            if (seen_cache) {
 604                error_report("-n and --cache can only be specified once");
 605                exit(EXIT_FAILURE);
 606            }
 607            seen_cache = true;
 608            if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 609                error_report("Invalid cache mode `%s'", optarg);
 610                exit(EXIT_FAILURE);
 611            }
 612            break;
 613        case QEMU_NBD_OPT_AIO:
 614            if (seen_aio) {
 615                error_report("--aio can only be specified once");
 616                exit(EXIT_FAILURE);
 617            }
 618            seen_aio = true;
 619            if (!strcmp(optarg, "native")) {
 620                flags |= BDRV_O_NATIVE_AIO;
 621            } else if (!strcmp(optarg, "threads")) {
 622                /* this is the default */
 623            } else {
 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                dev_offset = strtoll (optarg, &end, 0);
 665            if (*end) {
 666                error_report("Invalid offset `%s'", optarg);
 667                exit(EXIT_FAILURE);
 668            }
 669            if (dev_offset < 0) {
 670                error_report("Offset must be positive `%s'", optarg);
 671                exit(EXIT_FAILURE);
 672            }
 673            break;
 674        case 'l':
 675            if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 676                sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 677                                                  optarg, false);
 678                if (!sn_opts) {
 679                    error_report("Failed in parsing snapshot param `%s'",
 680                                 optarg);
 681                    exit(EXIT_FAILURE);
 682                }
 683            } else {
 684                sn_id_or_name = optarg;
 685            }
 686            /* fall through */
 687        case 'r':
 688            nbdflags |= NBD_FLAG_READ_ONLY;
 689            flags &= ~BDRV_O_RDWR;
 690            break;
 691        case 'P':
 692            partition = strtol(optarg, &end, 0);
 693            if (*end) {
 694                error_report("Invalid partition `%s'", optarg);
 695                exit(EXIT_FAILURE);
 696            }
 697            if (partition < 1 || partition > 8) {
 698                error_report("Invalid partition %d", partition);
 699                exit(EXIT_FAILURE);
 700            }
 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            shared = strtol(optarg, &end, 0);
 717            if (*end) {
 718                error_report("Invalid shared device number '%s'", optarg);
 719                exit(EXIT_FAILURE);
 720            }
 721            if (shared < 1) {
 722                error_report("Shared device number must be greater than 0");
 723                exit(EXIT_FAILURE);
 724            }
 725            break;
 726        case 'f':
 727            fmt = optarg;
 728            break;
 729        case 't':
 730            persistent = 1;
 731            break;
 732        case 'x':
 733            export_name = optarg;
 734            break;
 735        case 'D':
 736            export_description = optarg;
 737            break;
 738        case 'v':
 739            verbose = 1;
 740            break;
 741        case 'V':
 742            version(argv[0]);
 743            exit(0);
 744            break;
 745        case 'h':
 746            usage(argv[0]);
 747            exit(0);
 748            break;
 749        case '?':
 750            error_report("Try `%s --help' for more information.", argv[0]);
 751            exit(EXIT_FAILURE);
 752        case QEMU_NBD_OPT_OBJECT: {
 753            QemuOpts *opts;
 754            opts = qemu_opts_parse_noisily(&qemu_object_opts,
 755                                           optarg, true);
 756            if (!opts) {
 757                exit(EXIT_FAILURE);
 758            }
 759        }   break;
 760        case QEMU_NBD_OPT_TLSCREDS:
 761            tlscredsid = optarg;
 762            break;
 763        case QEMU_NBD_OPT_IMAGE_OPTS:
 764            imageOpts = true;
 765            break;
 766        case 'T':
 767            g_free(trace_file);
 768            trace_file = trace_opt_parse(optarg);
 769            break;
 770        case QEMU_NBD_OPT_FORK:
 771            fork_process = true;
 772            break;
 773        }
 774    }
 775
 776    if ((argc - optind) != 1) {
 777        error_report("Invalid number of arguments");
 778        error_printf("Try `%s --help' for more information.\n", argv[0]);
 779        exit(EXIT_FAILURE);
 780    }
 781
 782    if (qemu_opts_foreach(&qemu_object_opts,
 783                          user_creatable_add_opts_foreach,
 784                          NULL, NULL)) {
 785        exit(EXIT_FAILURE);
 786    }
 787
 788    if (!trace_init_backends()) {
 789        exit(1);
 790    }
 791    trace_init_file(trace_file);
 792    qemu_set_log(LOG_TRACE);
 793
 794    socket_activation = check_socket_activation();
 795    if (socket_activation == 0) {
 796        setup_address_and_port(&bindto, &port);
 797    } else {
 798        /* Using socket activation - check user didn't use -p etc. */
 799        const char *err_msg = socket_activation_validate_opts(device, sockpath,
 800                                                              bindto, port);
 801        if (err_msg != NULL) {
 802            error_report("%s", err_msg);
 803            exit(EXIT_FAILURE);
 804        }
 805
 806        /* qemu-nbd can only listen on a single socket.  */
 807        if (socket_activation > 1) {
 808            error_report("qemu-nbd does not support socket activation with %s > 1",
 809                         "LISTEN_FDS");
 810            exit(EXIT_FAILURE);
 811        }
 812    }
 813
 814    if (tlscredsid) {
 815        if (sockpath) {
 816            error_report("TLS is only supported with IPv4/IPv6");
 817            exit(EXIT_FAILURE);
 818        }
 819        if (device) {
 820            error_report("TLS is not supported with a host device");
 821            exit(EXIT_FAILURE);
 822        }
 823        if (!export_name) {
 824            /* Set the default NBD protocol export name, since
 825             * we *must* use new style protocol for TLS */
 826            export_name = "";
 827        }
 828        tlscreds = nbd_get_tls_creds(tlscredsid, &local_err);
 829        if (local_err) {
 830            error_report("Failed to get TLS creds %s",
 831                         error_get_pretty(local_err));
 832            exit(EXIT_FAILURE);
 833        }
 834    }
 835
 836    if (disconnect) {
 837        int nbdfd = open(argv[optind], O_RDWR);
 838        if (nbdfd < 0) {
 839            error_report("Cannot open %s: %s", argv[optind],
 840                         strerror(errno));
 841            exit(EXIT_FAILURE);
 842        }
 843        nbd_disconnect(nbdfd);
 844
 845        close(nbdfd);
 846
 847        printf("%s disconnected\n", argv[optind]);
 848
 849        return 0;
 850    }
 851
 852    if ((device && !verbose) || fork_process) {
 853        int stderr_fd[2];
 854        pid_t pid;
 855        int ret;
 856
 857        if (qemu_pipe(stderr_fd) < 0) {
 858            error_report("Error setting up communication pipe: %s",
 859                         strerror(errno));
 860            exit(EXIT_FAILURE);
 861        }
 862
 863        /* Now daemonize, but keep a communication channel open to
 864         * print errors and exit with the proper status code.
 865         */
 866        pid = fork();
 867        if (pid < 0) {
 868            error_report("Failed to fork: %s", strerror(errno));
 869            exit(EXIT_FAILURE);
 870        } else if (pid == 0) {
 871            close(stderr_fd[0]);
 872            ret = qemu_daemon(1, 0);
 873
 874            /* Temporarily redirect stderr to the parent's pipe...  */
 875            old_stderr = dup(STDERR_FILENO);
 876            dup2(stderr_fd[1], STDERR_FILENO);
 877            if (ret < 0) {
 878                error_report("Failed to daemonize: %s", strerror(errno));
 879                exit(EXIT_FAILURE);
 880            }
 881
 882            /* ... close the descriptor we inherited and go on.  */
 883            close(stderr_fd[1]);
 884        } else {
 885            bool errors = false;
 886            char *buf;
 887
 888            /* In the parent.  Print error messages from the child until
 889             * it closes the pipe.
 890             */
 891            close(stderr_fd[1]);
 892            buf = g_malloc(1024);
 893            while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
 894                errors = true;
 895                ret = qemu_write_full(STDERR_FILENO, buf, ret);
 896                if (ret < 0) {
 897                    exit(EXIT_FAILURE);
 898                }
 899            }
 900            if (ret < 0) {
 901                error_report("Cannot read from daemon: %s",
 902                             strerror(errno));
 903                exit(EXIT_FAILURE);
 904            }
 905
 906            /* Usually the daemon should not print any message.
 907             * Exit with zero status in that case.
 908             */
 909            exit(errors);
 910        }
 911    }
 912
 913    if (device != NULL && sockpath == NULL) {
 914        sockpath = g_malloc(128);
 915        snprintf(sockpath, 128, SOCKET_PATH, basename(device));
 916    }
 917
 918    if (socket_activation == 0) {
 919        server_ioc = qio_channel_socket_new();
 920        saddr = nbd_build_socket_address(sockpath, bindto, port);
 921        if (qio_channel_socket_listen_sync(server_ioc, saddr, &local_err) < 0) {
 922            object_unref(OBJECT(server_ioc));
 923            error_report_err(local_err);
 924            return 1;
 925        }
 926    } else {
 927        /* See comment in check_socket_activation above. */
 928        assert(socket_activation == 1);
 929        server_ioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD,
 930                                               &local_err);
 931        if (server_ioc == NULL) {
 932            error_report("Failed to use socket activation: %s",
 933                         error_get_pretty(local_err));
 934            exit(EXIT_FAILURE);
 935        }
 936    }
 937
 938    if (qemu_init_main_loop(&local_err)) {
 939        error_report_err(local_err);
 940        exit(EXIT_FAILURE);
 941    }
 942    bdrv_init();
 943    atexit(bdrv_close_all);
 944
 945    srcpath = argv[optind];
 946    if (imageOpts) {
 947        QemuOpts *opts;
 948        if (fmt) {
 949            error_report("--image-opts and -f are mutually exclusive");
 950            exit(EXIT_FAILURE);
 951        }
 952        opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
 953        if (!opts) {
 954            qemu_opts_reset(&file_opts);
 955            exit(EXIT_FAILURE);
 956        }
 957        options = qemu_opts_to_qdict(opts, NULL);
 958        qemu_opts_reset(&file_opts);
 959        blk = blk_new_open(NULL, NULL, options, flags, &local_err);
 960    } else {
 961        if (fmt) {
 962            options = qdict_new();
 963            qdict_put_str(options, "driver", fmt);
 964        }
 965        blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
 966    }
 967
 968    if (!blk) {
 969        error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
 970                          argv[optind]);
 971        exit(EXIT_FAILURE);
 972    }
 973    bs = blk_bs(blk);
 974
 975    blk_set_enable_write_cache(blk, !writethrough);
 976
 977    if (sn_opts) {
 978        ret = bdrv_snapshot_load_tmp(bs,
 979                                     qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
 980                                     qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
 981                                     &local_err);
 982    } else if (sn_id_or_name) {
 983        ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
 984                                                   &local_err);
 985    }
 986    if (ret < 0) {
 987        error_reportf_err(local_err, "Failed to load snapshot: ");
 988        exit(EXIT_FAILURE);
 989    }
 990
 991    bs->detect_zeroes = detect_zeroes;
 992    fd_size = blk_getlength(blk);
 993    if (fd_size < 0) {
 994        error_report("Failed to determine the image length: %s",
 995                     strerror(-fd_size));
 996        exit(EXIT_FAILURE);
 997    }
 998
 999    if (dev_offset >= fd_size) {
1000        error_report("Offset (%lld) has to be smaller than the image size "
1001                     "(%lld)",
1002                     (long long int)dev_offset, (long long int)fd_size);
1003        exit(EXIT_FAILURE);
1004    }
1005    fd_size -= dev_offset;
1006
1007    if (partition != -1) {
1008        ret = find_partition(blk, partition, &dev_offset, &fd_size);
1009        if (ret < 0) {
1010            error_report("Could not find partition %d: %s", partition,
1011                         strerror(-ret));
1012            exit(EXIT_FAILURE);
1013        }
1014    }
1015
1016    exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed,
1017                         writethrough, NULL, &local_err);
1018    if (!exp) {
1019        error_report_err(local_err);
1020        exit(EXIT_FAILURE);
1021    }
1022    if (export_name) {
1023        nbd_export_set_name(exp, export_name);
1024        nbd_export_set_description(exp, export_description);
1025        newproto = true;
1026    } else if (export_description) {
1027        error_report("Export description requires an export name");
1028        exit(EXIT_FAILURE);
1029    }
1030
1031    if (device) {
1032        int ret;
1033
1034        ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1035        if (ret != 0) {
1036            error_report("Failed to create client thread: %s", strerror(ret));
1037            exit(EXIT_FAILURE);
1038        }
1039    } else {
1040        /* Shut up GCC warnings.  */
1041        memset(&client_thread, 0, sizeof(client_thread));
1042    }
1043
1044    nbd_update_server_watch();
1045
1046    /* now when the initialization is (almost) complete, chdir("/")
1047     * to free any busy filesystems */
1048    if (chdir("/") < 0) {
1049        error_report("Could not chdir to root directory: %s",
1050                     strerror(errno));
1051        exit(EXIT_FAILURE);
1052    }
1053
1054    if (fork_process) {
1055        dup2(old_stderr, STDERR_FILENO);
1056        close(old_stderr);
1057    }
1058
1059    state = RUNNING;
1060    do {
1061        main_loop_wait(false);
1062        if (state == TERMINATE) {
1063            state = TERMINATING;
1064            nbd_export_close(exp);
1065            nbd_export_put(exp);
1066            exp = NULL;
1067        }
1068    } while (state != TERMINATED);
1069
1070    blk_unref(blk);
1071    if (sockpath) {
1072        unlink(sockpath);
1073    }
1074
1075    qemu_opts_del(sn_opts);
1076
1077    if (device) {
1078        void *ret;
1079        pthread_join(client_thread, &ret);
1080        exit(ret != NULL);
1081    } else {
1082        exit(EXIT_SUCCESS);
1083    }
1084}
1085