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 "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"  -P, --partition=NUM       only expose partition NUM\n"
 104"  -B, --bitmap=NAME         expose a persistent dirty bitmap\n"
 105"\n"
 106"General purpose options:\n"
 107"  -L, --list                list exports available from another NBD server\n"
 108"  --object type,id=ID,...   define an object such as 'secret' for providing\n"
 109"                            passwords and/or encryption keys\n"
 110"  --tls-creds=ID            use id of an earlier --object to provide TLS\n"
 111"  --tls-authz=ID            use id of an earlier --object to provide\n"
 112"                            authorization\n"
 113"  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
 114"                            specify tracing options\n"
 115"  --fork                    fork off the server process and exit the parent\n"
 116"                            once the server is running\n"
 117"  --pid-file=PATH           store the server's process ID in the given file\n"
 118#if HAVE_NBD_DEVICE
 119"\n"
 120"Kernel NBD client support:\n"
 121"  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
 122"  -d, --disconnect          disconnect the specified device\n"
 123#endif
 124"\n"
 125"Block device options:\n"
 126"  -f, --format=FORMAT       set image format (raw, qcow2, ...)\n"
 127"  -r, --read-only           export read-only\n"
 128"  -s, --snapshot            use FILE as an external snapshot, create a temporary\n"
 129"                            file with backing_file=FILE, redirect the write to\n"
 130"                            the temporary one\n"
 131"  -l, --load-snapshot=SNAPSHOT_PARAM\n"
 132"                            load an internal snapshot inside FILE and export it\n"
 133"                            as an read-only device, SNAPSHOT_PARAM format is\n"
 134"                            'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
 135"                            '[ID_OR_NAME]'\n"
 136"  -n, --nocache             disable host cache\n"
 137"      --cache=MODE          set cache mode (none, writeback, ...)\n"
 138"      --aio=MODE            set AIO mode (native or threads)\n"
 139"      --discard=MODE        set discard mode (ignore, unmap)\n"
 140"      --detect-zeroes=MODE  set detect-zeroes mode (off, on, unmap)\n"
 141"      --image-opts          treat FILE as a full set of image options\n"
 142"\n"
 143QEMU_HELP_BOTTOM "\n"
 144    , name, name, NBD_DEFAULT_PORT, "DEVICE");
 145}
 146
 147static void version(const char *name)
 148{
 149    printf(
 150"%s " QEMU_FULL_VERSION "\n"
 151"Written by Anthony Liguori.\n"
 152"\n"
 153QEMU_COPYRIGHT "\n"
 154"This is free software; see the source for copying conditions.  There is NO\n"
 155"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 156    , name);
 157}
 158
 159struct partition_record
 160{
 161    uint8_t bootable;
 162    uint8_t start_head;
 163    uint32_t start_cylinder;
 164    uint8_t start_sector;
 165    uint8_t system;
 166    uint8_t end_head;
 167    uint8_t end_cylinder;
 168    uint8_t end_sector;
 169    uint32_t start_sector_abs;
 170    uint32_t nb_sectors_abs;
 171};
 172
 173static void read_partition(uint8_t *p, struct partition_record *r)
 174{
 175    r->bootable = p[0];
 176    r->start_head = p[1];
 177    r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
 178    r->start_sector = p[2] & 0x3f;
 179    r->system = p[4];
 180    r->end_head = p[5];
 181    r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
 182    r->end_sector = p[6] & 0x3f;
 183
 184    r->start_sector_abs = ldl_le_p(p + 8);
 185    r->nb_sectors_abs   = ldl_le_p(p + 12);
 186}
 187
 188static int find_partition(BlockBackend *blk, int partition,
 189                          uint64_t *offset, uint64_t *size)
 190{
 191    struct partition_record mbr[4];
 192    uint8_t data[MBR_SIZE];
 193    int i;
 194    int ext_partnum = 4;
 195    int ret;
 196
 197    ret = blk_pread(blk, 0, data, sizeof(data));
 198    if (ret < 0) {
 199        error_report("error while reading: %s", strerror(-ret));
 200        exit(EXIT_FAILURE);
 201    }
 202
 203    if (data[510] != 0x55 || data[511] != 0xaa) {
 204        return -EINVAL;
 205    }
 206
 207    for (i = 0; i < 4; i++) {
 208        read_partition(&data[446 + 16 * i], &mbr[i]);
 209
 210        if (!mbr[i].system || !mbr[i].nb_sectors_abs) {
 211            continue;
 212        }
 213
 214        if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
 215            struct partition_record ext[4];
 216            uint8_t data1[MBR_SIZE];
 217            int j;
 218
 219            ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE,
 220                            data1, sizeof(data1));
 221            if (ret < 0) {
 222                error_report("error while reading: %s", strerror(-ret));
 223                exit(EXIT_FAILURE);
 224            }
 225
 226            for (j = 0; j < 4; j++) {
 227                read_partition(&data1[446 + 16 * j], &ext[j]);
 228                if (!ext[j].system || !ext[j].nb_sectors_abs) {
 229                    continue;
 230                }
 231
 232                if ((ext_partnum + j + 1) == partition) {
 233                    *offset = (uint64_t)ext[j].start_sector_abs << 9;
 234                    *size = (uint64_t)ext[j].nb_sectors_abs << 9;
 235                    return 0;
 236                }
 237            }
 238            ext_partnum += 4;
 239        } else if ((i + 1) == partition) {
 240            *offset = (uint64_t)mbr[i].start_sector_abs << 9;
 241            *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
 242            return 0;
 243        }
 244    }
 245
 246    return -ENOENT;
 247}
 248
 249static void termsig_handler(int signum)
 250{
 251    atomic_cmpxchg(&state, RUNNING, TERMINATE);
 252    qemu_notify_event();
 253}
 254
 255
 256static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
 257                                const char *hostname)
 258{
 259    int ret = EXIT_FAILURE;
 260    int rc;
 261    Error *err = NULL;
 262    QIOChannelSocket *sioc;
 263    NBDExportInfo *list;
 264    int i, j;
 265
 266    sioc = qio_channel_socket_new();
 267    if (qio_channel_socket_connect_sync(sioc, saddr, &err) < 0) {
 268        error_report_err(err);
 269        return EXIT_FAILURE;
 270    }
 271    rc = nbd_receive_export_list(QIO_CHANNEL(sioc), tls, hostname, &list,
 272                                 &err);
 273    if (rc < 0) {
 274        if (err) {
 275            error_report_err(err);
 276        }
 277        goto out;
 278    }
 279    printf("exports available: %d\n", rc);
 280    for (i = 0; i < rc; i++) {
 281        printf(" export: '%s'\n", list[i].name);
 282        if (list[i].description && *list[i].description) {
 283            printf("  description: %s\n", list[i].description);
 284        }
 285        if (list[i].flags & NBD_FLAG_HAS_FLAGS) {
 286            static const char *const flag_names[] = {
 287                [NBD_FLAG_READ_ONLY_BIT]            = "readonly",
 288                [NBD_FLAG_SEND_FLUSH_BIT]           = "flush",
 289                [NBD_FLAG_SEND_FUA_BIT]             = "fua",
 290                [NBD_FLAG_ROTATIONAL_BIT]           = "rotational",
 291                [NBD_FLAG_SEND_TRIM_BIT]            = "trim",
 292                [NBD_FLAG_SEND_WRITE_ZEROES_BIT]    = "zeroes",
 293                [NBD_FLAG_SEND_DF_BIT]              = "df",
 294                [NBD_FLAG_CAN_MULTI_CONN_BIT]       = "multi",
 295                [NBD_FLAG_SEND_RESIZE_BIT]          = "resize",
 296                [NBD_FLAG_SEND_CACHE_BIT]           = "cache",
 297            };
 298
 299            printf("  size:  %" PRIu64 "\n", list[i].size);
 300            printf("  flags: 0x%x (", list[i].flags);
 301            for (size_t bit = 0; bit < ARRAY_SIZE(flag_names); bit++) {
 302                if (flag_names[bit] && (list[i].flags & (1 << bit))) {
 303                    printf(" %s", flag_names[bit]);
 304                }
 305            }
 306            printf(" )\n");
 307        }
 308        if (list[i].min_block) {
 309            printf("  min block: %u\n", list[i].min_block);
 310            printf("  opt block: %u\n", list[i].opt_block);
 311            printf("  max block: %u\n", list[i].max_block);
 312        }
 313        if (list[i].n_contexts) {
 314            printf("  available meta contexts: %d\n", list[i].n_contexts);
 315            for (j = 0; j < list[i].n_contexts; j++) {
 316                printf("   %s\n", list[i].contexts[j]);
 317            }
 318        }
 319    }
 320    nbd_free_export_list(list, rc);
 321
 322    ret = EXIT_SUCCESS;
 323 out:
 324    object_unref(OBJECT(sioc));
 325    return ret;
 326}
 327
 328
 329#if HAVE_NBD_DEVICE
 330static void *show_parts(void *arg)
 331{
 332    char *device = arg;
 333    int nbd;
 334
 335    /* linux just needs an open() to trigger
 336     * the partition table update
 337     * but remember to load the module with max_part != 0 :
 338     *     modprobe nbd max_part=63
 339     */
 340    nbd = open(device, O_RDWR);
 341    if (nbd >= 0) {
 342        close(nbd);
 343    }
 344    return NULL;
 345}
 346
 347static void *nbd_client_thread(void *arg)
 348{
 349    char *device = arg;
 350    NBDExportInfo info = { .request_sizes = false, .name = g_strdup("") };
 351    QIOChannelSocket *sioc;
 352    int fd;
 353    int ret;
 354    pthread_t show_parts_thread;
 355    Error *local_error = NULL;
 356
 357    sioc = qio_channel_socket_new();
 358    if (qio_channel_socket_connect_sync(sioc,
 359                                        saddr,
 360                                        &local_error) < 0) {
 361        error_report_err(local_error);
 362        goto out;
 363    }
 364
 365    ret = nbd_receive_negotiate(QIO_CHANNEL(sioc),
 366                                NULL, NULL, NULL, &info, &local_error);
 367    if (ret < 0) {
 368        if (local_error) {
 369            error_report_err(local_error);
 370        }
 371        goto out_socket;
 372    }
 373
 374    fd = open(device, O_RDWR);
 375    if (fd < 0) {
 376        /* Linux-only, we can use %m in printf.  */
 377        error_report("Failed to open %s: %m", device);
 378        goto out_socket;
 379    }
 380
 381    ret = nbd_init(fd, sioc, &info, &local_error);
 382    if (ret < 0) {
 383        error_report_err(local_error);
 384        goto out_fd;
 385    }
 386
 387    /* update partition table */
 388    pthread_create(&show_parts_thread, NULL, show_parts, device);
 389
 390    if (verbose) {
 391        fprintf(stderr, "NBD device %s is now connected to %s\n",
 392                device, srcpath);
 393    } else {
 394        /* Close stderr so that the qemu-nbd process exits.  */
 395        dup2(STDOUT_FILENO, STDERR_FILENO);
 396    }
 397
 398    ret = nbd_client(fd);
 399    if (ret) {
 400        goto out_fd;
 401    }
 402    close(fd);
 403    object_unref(OBJECT(sioc));
 404    g_free(info.name);
 405    kill(getpid(), SIGTERM);
 406    return (void *) EXIT_SUCCESS;
 407
 408out_fd:
 409    close(fd);
 410out_socket:
 411    object_unref(OBJECT(sioc));
 412out:
 413    g_free(info.name);
 414    kill(getpid(), SIGTERM);
 415    return (void *) EXIT_FAILURE;
 416}
 417#endif /* HAVE_NBD_DEVICE */
 418
 419static int nbd_can_accept(void)
 420{
 421    return state == RUNNING && nb_fds < shared;
 422}
 423
 424static void nbd_export_closed(NBDExport *export)
 425{
 426    assert(state == TERMINATING);
 427    state = TERMINATED;
 428}
 429
 430static void nbd_update_server_watch(void);
 431
 432static void nbd_client_closed(NBDClient *client, bool negotiated)
 433{
 434    nb_fds--;
 435    if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
 436        state = TERMINATE;
 437    }
 438    nbd_update_server_watch();
 439    nbd_client_put(client);
 440}
 441
 442static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
 443                       gpointer opaque)
 444{
 445    if (state >= TERMINATE) {
 446        return;
 447    }
 448
 449    nb_fds++;
 450    nbd_update_server_watch();
 451    nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
 452}
 453
 454static void nbd_update_server_watch(void)
 455{
 456    if (nbd_can_accept()) {
 457        qio_net_listener_set_client_func(server, nbd_accept, NULL, NULL);
 458    } else {
 459        qio_net_listener_set_client_func(server, NULL, NULL, NULL);
 460    }
 461}
 462
 463
 464static SocketAddress *nbd_build_socket_address(const char *sockpath,
 465                                               const char *bindto,
 466                                               const char *port)
 467{
 468    SocketAddress *saddr;
 469
 470    saddr = g_new0(SocketAddress, 1);
 471    if (sockpath) {
 472        saddr->type = SOCKET_ADDRESS_TYPE_UNIX;
 473        saddr->u.q_unix.path = g_strdup(sockpath);
 474    } else {
 475        InetSocketAddress *inet;
 476        saddr->type = SOCKET_ADDRESS_TYPE_INET;
 477        inet = &saddr->u.inet;
 478        inet->host = g_strdup(bindto);
 479        if (port) {
 480            inet->port = g_strdup(port);
 481        } else  {
 482            inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 483        }
 484    }
 485
 486    return saddr;
 487}
 488
 489
 490static QemuOptsList file_opts = {
 491    .name = "file",
 492    .implied_opt_name = "file",
 493    .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
 494    .desc = {
 495        /* no elements => accept any params */
 496        { /* end of list */ }
 497    },
 498};
 499
 500static QemuOptsList qemu_object_opts = {
 501    .name = "object",
 502    .implied_opt_name = "qom-type",
 503    .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
 504    .desc = {
 505        { }
 506    },
 507};
 508
 509
 510
 511static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, bool list,
 512                                          Error **errp)
 513{
 514    Object *obj;
 515    QCryptoTLSCreds *creds;
 516
 517    obj = object_resolve_path_component(
 518        object_get_objects_root(), id);
 519    if (!obj) {
 520        error_setg(errp, "No TLS credentials with id '%s'",
 521                   id);
 522        return NULL;
 523    }
 524    creds = (QCryptoTLSCreds *)
 525        object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 526    if (!creds) {
 527        error_setg(errp, "Object with id '%s' is not TLS credentials",
 528                   id);
 529        return NULL;
 530    }
 531
 532    if (list) {
 533        if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
 534            error_setg(errp,
 535                       "Expecting TLS credentials with a client endpoint");
 536            return NULL;
 537        }
 538    } else {
 539        if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
 540            error_setg(errp,
 541                       "Expecting TLS credentials with a server endpoint");
 542            return NULL;
 543        }
 544    }
 545    object_ref(obj);
 546    return creds;
 547}
 548
 549static void setup_address_and_port(const char **address, const char **port)
 550{
 551    if (*address == NULL) {
 552        *address = "0.0.0.0";
 553    }
 554
 555    if (*port == NULL) {
 556        *port = stringify(NBD_DEFAULT_PORT);
 557    }
 558}
 559
 560/*
 561 * Check socket parameters compatibility when socket activation is used.
 562 */
 563static const char *socket_activation_validate_opts(const char *device,
 564                                                   const char *sockpath,
 565                                                   const char *address,
 566                                                   const char *port,
 567                                                   bool list)
 568{
 569    if (device != NULL) {
 570        return "NBD device can't be set when using socket activation";
 571    }
 572
 573    if (sockpath != NULL) {
 574        return "Unix socket can't be set when using socket activation";
 575    }
 576
 577    if (address != NULL) {
 578        return "The interface can't be set when using socket activation";
 579    }
 580
 581    if (port != NULL) {
 582        return "TCP port number can't be set when using socket activation";
 583    }
 584
 585    if (list) {
 586        return "List mode is incompatible with socket activation";
 587    }
 588
 589    return NULL;
 590}
 591
 592static void qemu_nbd_shutdown(void)
 593{
 594    job_cancel_sync_all();
 595    bdrv_close_all();
 596}
 597
 598int main(int argc, char **argv)
 599{
 600    BlockBackend *blk;
 601    BlockDriverState *bs;
 602    uint64_t dev_offset = 0;
 603    uint16_t nbdflags = 0;
 604    bool disconnect = false;
 605    const char *bindto = NULL;
 606    const char *port = NULL;
 607    char *sockpath = NULL;
 608    char *device = NULL;
 609    int64_t fd_size;
 610    QemuOpts *sn_opts = NULL;
 611    const char *sn_id_or_name = NULL;
 612    const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:B:L";
 613    struct option lopt[] = {
 614        { "help", no_argument, NULL, 'h' },
 615        { "version", no_argument, NULL, 'V' },
 616        { "bind", required_argument, NULL, 'b' },
 617        { "port", required_argument, NULL, 'p' },
 618        { "socket", required_argument, NULL, 'k' },
 619        { "offset", required_argument, NULL, 'o' },
 620        { "read-only", no_argument, NULL, 'r' },
 621        { "partition", required_argument, NULL, 'P' },
 622        { "bitmap", required_argument, NULL, 'B' },
 623        { "connect", required_argument, NULL, 'c' },
 624        { "disconnect", no_argument, NULL, 'd' },
 625        { "list", no_argument, NULL, 'L' },
 626        { "snapshot", no_argument, NULL, 's' },
 627        { "load-snapshot", required_argument, NULL, 'l' },
 628        { "nocache", no_argument, NULL, 'n' },
 629        { "cache", required_argument, NULL, QEMU_NBD_OPT_CACHE },
 630        { "aio", required_argument, NULL, QEMU_NBD_OPT_AIO },
 631        { "discard", required_argument, NULL, QEMU_NBD_OPT_DISCARD },
 632        { "detect-zeroes", required_argument, NULL,
 633          QEMU_NBD_OPT_DETECT_ZEROES },
 634        { "shared", required_argument, NULL, 'e' },
 635        { "format", required_argument, NULL, 'f' },
 636        { "persistent", no_argument, NULL, 't' },
 637        { "verbose", no_argument, NULL, 'v' },
 638        { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
 639        { "export-name", required_argument, NULL, 'x' },
 640        { "description", required_argument, NULL, 'D' },
 641        { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 642        { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
 643        { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
 644        { "trace", required_argument, NULL, 'T' },
 645        { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
 646        { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE },
 647        { NULL, 0, NULL, 0 }
 648    };
 649    int ch;
 650    int opt_ind = 0;
 651    int flags = BDRV_O_RDWR;
 652    int partition = 0;
 653    int ret = 0;
 654    bool seen_cache = false;
 655    bool seen_discard = false;
 656    bool seen_aio = false;
 657    pthread_t client_thread;
 658    const char *fmt = NULL;
 659    Error *local_err = NULL;
 660    BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
 661    QDict *options = NULL;
 662    const char *export_name = NULL; /* defaults to "" later for server mode */
 663    const char *export_description = NULL;
 664    const char *bitmap = NULL;
 665    const char *tlscredsid = NULL;
 666    bool imageOpts = false;
 667    bool writethrough = true;
 668    char *trace_file = NULL;
 669    bool fork_process = false;
 670    bool list = false;
 671    int old_stderr = -1;
 672    unsigned socket_activation;
 673    const char *pid_file_name = NULL;
 674
 675    /* The client thread uses SIGTERM to interrupt the server.  A signal
 676     * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
 677     */
 678    struct sigaction sa_sigterm;
 679    memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 680    sa_sigterm.sa_handler = termsig_handler;
 681    sigaction(SIGTERM, &sa_sigterm, NULL);
 682
 683#ifdef CONFIG_POSIX
 684    signal(SIGPIPE, SIG_IGN);
 685#endif
 686
 687    error_init(argv[0]);
 688    module_call_init(MODULE_INIT_TRACE);
 689    qcrypto_init(&error_fatal);
 690
 691    module_call_init(MODULE_INIT_QOM);
 692    qemu_add_opts(&qemu_object_opts);
 693    qemu_add_opts(&qemu_trace_opts);
 694    qemu_init_exec_dir(argv[0]);
 695
 696    while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 697        switch (ch) {
 698        case 's':
 699            flags |= BDRV_O_SNAPSHOT;
 700            break;
 701        case 'n':
 702            optarg = (char *) "none";
 703            /* fallthrough */
 704        case QEMU_NBD_OPT_CACHE:
 705            if (seen_cache) {
 706                error_report("-n and --cache can only be specified once");
 707                exit(EXIT_FAILURE);
 708            }
 709            seen_cache = true;
 710            if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) == -1) {
 711                error_report("Invalid cache mode `%s'", optarg);
 712                exit(EXIT_FAILURE);
 713            }
 714            break;
 715        case QEMU_NBD_OPT_AIO:
 716            if (seen_aio) {
 717                error_report("--aio can only be specified once");
 718                exit(EXIT_FAILURE);
 719            }
 720            seen_aio = true;
 721            if (!strcmp(optarg, "native")) {
 722                flags |= BDRV_O_NATIVE_AIO;
 723            } else if (!strcmp(optarg, "threads")) {
 724                /* this is the default */
 725            } else {
 726               error_report("invalid aio mode `%s'", optarg);
 727               exit(EXIT_FAILURE);
 728            }
 729            break;
 730        case QEMU_NBD_OPT_DISCARD:
 731            if (seen_discard) {
 732                error_report("--discard can only be specified once");
 733                exit(EXIT_FAILURE);
 734            }
 735            seen_discard = true;
 736            if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
 737                error_report("Invalid discard mode `%s'", optarg);
 738                exit(EXIT_FAILURE);
 739            }
 740            break;
 741        case QEMU_NBD_OPT_DETECT_ZEROES:
 742            detect_zeroes =
 743                qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
 744                                optarg,
 745                                BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
 746                                &local_err);
 747            if (local_err) {
 748                error_reportf_err(local_err,
 749                                  "Failed to parse detect_zeroes mode: ");
 750                exit(EXIT_FAILURE);
 751            }
 752            if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
 753                !(flags & BDRV_O_UNMAP)) {
 754                error_report("setting detect-zeroes to unmap is not allowed "
 755                             "without setting discard operation to unmap");
 756                exit(EXIT_FAILURE);
 757            }
 758            break;
 759        case 'b':
 760            bindto = optarg;
 761            break;
 762        case 'p':
 763            port = optarg;
 764            break;
 765        case 'o':
 766            if (qemu_strtou64(optarg, NULL, 0, &dev_offset) < 0) {
 767                error_report("Invalid offset '%s'", optarg);
 768                exit(EXIT_FAILURE);
 769            }
 770            break;
 771        case 'l':
 772            if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
 773                sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
 774                                                  optarg, false);
 775                if (!sn_opts) {
 776                    error_report("Failed in parsing snapshot param `%s'",
 777                                 optarg);
 778                    exit(EXIT_FAILURE);
 779                }
 780            } else {
 781                sn_id_or_name = optarg;
 782            }
 783            /* fall through */
 784        case 'r':
 785            nbdflags |= NBD_FLAG_READ_ONLY;
 786            flags &= ~BDRV_O_RDWR;
 787            break;
 788        case 'P':
 789            warn_report("The '-P' option is deprecated; use --image-opts with "
 790                        "a raw device wrapper for subset exports instead");
 791            if (qemu_strtoi(optarg, NULL, 0, &partition) < 0 ||
 792                partition < 1 || partition > 8) {
 793                error_report("Invalid partition '%s'", optarg);
 794                exit(EXIT_FAILURE);
 795            }
 796            break;
 797        case 'B':
 798            bitmap = optarg;
 799            break;
 800        case 'k':
 801            sockpath = optarg;
 802            if (sockpath[0] != '/') {
 803                error_report("socket path must be absolute");
 804                exit(EXIT_FAILURE);
 805            }
 806            break;
 807        case 'd':
 808            disconnect = true;
 809            break;
 810        case 'c':
 811            device = optarg;
 812            break;
 813        case 'e':
 814            if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
 815                shared < 1) {
 816                error_report("Invalid shared device number '%s'", optarg);
 817                exit(EXIT_FAILURE);
 818            }
 819            break;
 820        case 'f':
 821            fmt = optarg;
 822            break;
 823        case 't':
 824            persistent = 1;
 825            break;
 826        case 'x':
 827            export_name = optarg;
 828            break;
 829        case 'D':
 830            export_description = optarg;
 831            break;
 832        case 'v':
 833            verbose = 1;
 834            break;
 835        case 'V':
 836            version(argv[0]);
 837            exit(0);
 838            break;
 839        case 'h':
 840            usage(argv[0]);
 841            exit(0);
 842            break;
 843        case '?':
 844            error_report("Try `%s --help' for more information.", argv[0]);
 845            exit(EXIT_FAILURE);
 846        case QEMU_NBD_OPT_OBJECT: {
 847            QemuOpts *opts;
 848            opts = qemu_opts_parse_noisily(&qemu_object_opts,
 849                                           optarg, true);
 850            if (!opts) {
 851                exit(EXIT_FAILURE);
 852            }
 853        }   break;
 854        case QEMU_NBD_OPT_TLSCREDS:
 855            tlscredsid = optarg;
 856            break;
 857        case QEMU_NBD_OPT_IMAGE_OPTS:
 858            imageOpts = true;
 859            break;
 860        case 'T':
 861            g_free(trace_file);
 862            trace_file = trace_opt_parse(optarg);
 863            break;
 864        case QEMU_NBD_OPT_TLSAUTHZ:
 865            tlsauthz = optarg;
 866            break;
 867        case QEMU_NBD_OPT_FORK:
 868            fork_process = true;
 869            break;
 870        case 'L':
 871            list = true;
 872            break;
 873        case QEMU_NBD_OPT_PID_FILE:
 874            pid_file_name = optarg;
 875            break;
 876        }
 877    }
 878
 879    if (list) {
 880        if (argc != optind) {
 881            error_report("List mode is incompatible with a file name");
 882            exit(EXIT_FAILURE);
 883        }
 884        if (export_name || export_description || dev_offset || partition ||
 885            device || disconnect || fmt || sn_id_or_name || bitmap ||
 886            seen_aio || seen_discard || seen_cache) {
 887            error_report("List mode is incompatible with per-device settings");
 888            exit(EXIT_FAILURE);
 889        }
 890        if (fork_process) {
 891            error_report("List mode is incompatible with forking");
 892            exit(EXIT_FAILURE);
 893        }
 894    } else if ((argc - optind) != 1) {
 895        error_report("Invalid number of arguments");
 896        error_printf("Try `%s --help' for more information.\n", argv[0]);
 897        exit(EXIT_FAILURE);
 898    } else if (!export_name) {
 899        export_name = "";
 900    }
 901
 902    qemu_opts_foreach(&qemu_object_opts,
 903                      user_creatable_add_opts_foreach,
 904                      NULL, &error_fatal);
 905
 906    if (!trace_init_backends()) {
 907        exit(1);
 908    }
 909    trace_init_file(trace_file);
 910    qemu_set_log(LOG_TRACE);
 911
 912    socket_activation = check_socket_activation();
 913    if (socket_activation == 0) {
 914        setup_address_and_port(&bindto, &port);
 915    } else {
 916        /* Using socket activation - check user didn't use -p etc. */
 917        const char *err_msg = socket_activation_validate_opts(device, sockpath,
 918                                                              bindto, port,
 919                                                              list);
 920        if (err_msg != NULL) {
 921            error_report("%s", err_msg);
 922            exit(EXIT_FAILURE);
 923        }
 924
 925        /* qemu-nbd can only listen on a single socket.  */
 926        if (socket_activation > 1) {
 927            error_report("qemu-nbd does not support socket activation with %s > 1",
 928                         "LISTEN_FDS");
 929            exit(EXIT_FAILURE);
 930        }
 931    }
 932
 933    if (tlscredsid) {
 934        if (sockpath) {
 935            error_report("TLS is only supported with IPv4/IPv6");
 936            exit(EXIT_FAILURE);
 937        }
 938        if (device) {
 939            error_report("TLS is not supported with a host device");
 940            exit(EXIT_FAILURE);
 941        }
 942        if (tlsauthz && list) {
 943            error_report("TLS authorization is incompatible with export list");
 944            exit(EXIT_FAILURE);
 945        }
 946        tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
 947        if (local_err) {
 948            error_report("Failed to get TLS creds %s",
 949                         error_get_pretty(local_err));
 950            exit(EXIT_FAILURE);
 951        }
 952    } else {
 953        if (tlsauthz) {
 954            error_report("--tls-authz is not permitted without --tls-creds");
 955            exit(EXIT_FAILURE);
 956        }
 957    }
 958
 959    if (list) {
 960        saddr = nbd_build_socket_address(sockpath, bindto, port);
 961        return qemu_nbd_client_list(saddr, tlscreds, bindto);
 962    }
 963
 964#if !HAVE_NBD_DEVICE
 965    if (disconnect || device) {
 966        error_report("Kernel /dev/nbdN support not available");
 967        exit(EXIT_FAILURE);
 968    }
 969#else /* HAVE_NBD_DEVICE */
 970    if (disconnect) {
 971        int nbdfd = open(argv[optind], O_RDWR);
 972        if (nbdfd < 0) {
 973            error_report("Cannot open %s: %s", argv[optind],
 974                         strerror(errno));
 975            exit(EXIT_FAILURE);
 976        }
 977        nbd_disconnect(nbdfd);
 978
 979        close(nbdfd);
 980
 981        printf("%s disconnected\n", argv[optind]);
 982
 983        return 0;
 984    }
 985#endif
 986
 987    if ((device && !verbose) || fork_process) {
 988        int stderr_fd[2];
 989        pid_t pid;
 990        int ret;
 991
 992        if (qemu_pipe(stderr_fd) < 0) {
 993            error_report("Error setting up communication pipe: %s",
 994                         strerror(errno));
 995            exit(EXIT_FAILURE);
 996        }
 997
 998        /* Now daemonize, but keep a communication channel open to
 999         * print errors and exit with the proper status code.
1000         */
1001        pid = fork();
1002        if (pid < 0) {
1003            error_report("Failed to fork: %s", strerror(errno));
1004            exit(EXIT_FAILURE);
1005        } else if (pid == 0) {
1006            close(stderr_fd[0]);
1007
1008            old_stderr = dup(STDERR_FILENO);
1009            ret = qemu_daemon(1, 0);
1010
1011            /* Temporarily redirect stderr to the parent's pipe...  */
1012            dup2(stderr_fd[1], STDERR_FILENO);
1013            if (ret < 0) {
1014                error_report("Failed to daemonize: %s", strerror(errno));
1015                exit(EXIT_FAILURE);
1016            }
1017
1018            /* ... close the descriptor we inherited and go on.  */
1019            close(stderr_fd[1]);
1020        } else {
1021            bool errors = false;
1022            char *buf;
1023
1024            /* In the parent.  Print error messages from the child until
1025             * it closes the pipe.
1026             */
1027            close(stderr_fd[1]);
1028            buf = g_malloc(1024);
1029            while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
1030                errors = true;
1031                ret = qemu_write_full(STDERR_FILENO, buf, ret);
1032                if (ret < 0) {
1033                    exit(EXIT_FAILURE);
1034                }
1035            }
1036            if (ret < 0) {
1037                error_report("Cannot read from daemon: %s",
1038                             strerror(errno));
1039                exit(EXIT_FAILURE);
1040            }
1041
1042            /* Usually the daemon should not print any message.
1043             * Exit with zero status in that case.
1044             */
1045            exit(errors);
1046        }
1047    }
1048
1049    if (device != NULL && sockpath == NULL) {
1050        sockpath = g_malloc(128);
1051        snprintf(sockpath, 128, SOCKET_PATH, basename(device));
1052    }
1053
1054    server = qio_net_listener_new();
1055    if (socket_activation == 0) {
1056        saddr = nbd_build_socket_address(sockpath, bindto, port);
1057        if (qio_net_listener_open_sync(server, saddr, &local_err) < 0) {
1058            object_unref(OBJECT(server));
1059            error_report_err(local_err);
1060            exit(EXIT_FAILURE);
1061        }
1062    } else {
1063        size_t i;
1064        /* See comment in check_socket_activation above. */
1065        for (i = 0; i < socket_activation; i++) {
1066            QIOChannelSocket *sioc;
1067            sioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD + i,
1068                                             &local_err);
1069            if (sioc == NULL) {
1070                object_unref(OBJECT(server));
1071                error_report("Failed to use socket activation: %s",
1072                             error_get_pretty(local_err));
1073                exit(EXIT_FAILURE);
1074            }
1075            qio_net_listener_add(server, sioc);
1076            object_unref(OBJECT(sioc));
1077        }
1078    }
1079
1080    if (qemu_init_main_loop(&local_err)) {
1081        error_report_err(local_err);
1082        exit(EXIT_FAILURE);
1083    }
1084    bdrv_init();
1085    atexit(qemu_nbd_shutdown);
1086
1087    srcpath = argv[optind];
1088    if (imageOpts) {
1089        QemuOpts *opts;
1090        if (fmt) {
1091            error_report("--image-opts and -f are mutually exclusive");
1092            exit(EXIT_FAILURE);
1093        }
1094        opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
1095        if (!opts) {
1096            qemu_opts_reset(&file_opts);
1097            exit(EXIT_FAILURE);
1098        }
1099        options = qemu_opts_to_qdict(opts, NULL);
1100        qemu_opts_reset(&file_opts);
1101        blk = blk_new_open(NULL, NULL, options, flags, &local_err);
1102    } else {
1103        if (fmt) {
1104            options = qdict_new();
1105            qdict_put_str(options, "driver", fmt);
1106        }
1107        blk = blk_new_open(srcpath, NULL, options, flags, &local_err);
1108    }
1109
1110    if (!blk) {
1111        error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
1112                          argv[optind]);
1113        exit(EXIT_FAILURE);
1114    }
1115    bs = blk_bs(blk);
1116
1117    blk_set_enable_write_cache(blk, !writethrough);
1118
1119    if (sn_opts) {
1120        ret = bdrv_snapshot_load_tmp(bs,
1121                                     qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
1122                                     qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
1123                                     &local_err);
1124    } else if (sn_id_or_name) {
1125        ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name,
1126                                                   &local_err);
1127    }
1128    if (ret < 0) {
1129        error_reportf_err(local_err, "Failed to load snapshot: ");
1130        exit(EXIT_FAILURE);
1131    }
1132
1133    bs->detect_zeroes = detect_zeroes;
1134    fd_size = blk_getlength(blk);
1135    if (fd_size < 0) {
1136        error_report("Failed to determine the image length: %s",
1137                     strerror(-fd_size));
1138        exit(EXIT_FAILURE);
1139    }
1140
1141    if (dev_offset >= fd_size) {
1142        error_report("Offset (%" PRIu64 ") has to be smaller than the image "
1143                     "size (%" PRId64 ")", dev_offset, fd_size);
1144        exit(EXIT_FAILURE);
1145    }
1146    fd_size -= dev_offset;
1147
1148    if (partition) {
1149        uint64_t limit;
1150
1151        if (dev_offset) {
1152            error_report("Cannot request partition and offset together");
1153            exit(EXIT_FAILURE);
1154        }
1155        ret = find_partition(blk, partition, &dev_offset, &limit);
1156        if (ret < 0) {
1157            error_report("Could not find partition %d: %s", partition,
1158                         strerror(-ret));
1159            exit(EXIT_FAILURE);
1160        }
1161        /*
1162         * MBR partition limits are (32-bit << 9); this assert lets
1163         * the compiler know that we can't overflow 64 bits.
1164         */
1165        assert(dev_offset + limit >= dev_offset);
1166        if (dev_offset + limit > fd_size) {
1167            error_report("Discovered partition %d at offset %" PRIu64
1168                         " size %" PRIu64 ", but size exceeds file length %"
1169                         PRId64, partition, dev_offset, limit, fd_size);
1170            exit(EXIT_FAILURE);
1171        }
1172        fd_size = limit;
1173    }
1174
1175    export = nbd_export_new(bs, dev_offset, fd_size, export_name,
1176                            export_description, bitmap, nbdflags,
1177                            nbd_export_closed, writethrough, NULL,
1178                            &error_fatal);
1179
1180    if (device) {
1181#if HAVE_NBD_DEVICE
1182        int ret;
1183
1184        ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
1185        if (ret != 0) {
1186            error_report("Failed to create client thread: %s", strerror(ret));
1187            exit(EXIT_FAILURE);
1188        }
1189#endif
1190    } else {
1191        /* Shut up GCC warnings.  */
1192        memset(&client_thread, 0, sizeof(client_thread));
1193    }
1194
1195    nbd_update_server_watch();
1196
1197    if (pid_file_name) {
1198        qemu_write_pidfile(pid_file_name, &error_fatal);
1199    }
1200
1201    /* now when the initialization is (almost) complete, chdir("/")
1202     * to free any busy filesystems */
1203    if (chdir("/") < 0) {
1204        error_report("Could not chdir to root directory: %s",
1205                     strerror(errno));
1206        exit(EXIT_FAILURE);
1207    }
1208
1209    if (fork_process) {
1210        dup2(old_stderr, STDERR_FILENO);
1211        close(old_stderr);
1212    }
1213
1214    state = RUNNING;
1215    do {
1216        main_loop_wait(false);
1217        if (state == TERMINATE) {
1218            state = TERMINATING;
1219            nbd_export_close(export);
1220            nbd_export_put(export);
1221            export = NULL;
1222        }
1223    } while (state != TERMINATED);
1224
1225    blk_unref(blk);
1226    if (sockpath) {
1227        unlink(sockpath);
1228    }
1229
1230    qemu_opts_del(sn_opts);
1231
1232    if (device) {
1233        void *ret;
1234        pthread_join(client_thread, &ret);
1235        exit(ret != NULL);
1236    } else {
1237        exit(EXIT_SUCCESS);
1238    }
1239}
1240