block/nbd.c

   1 /*
   2  * QEMU Block driver for  NBD
   3  *
   4  * Copyright (C) 2008 Bull S.A.S.
   5  *     Author: Laurent Vivier <Laurent.Vivier@bull.net>
   6  *
   7  * Some parts:
   8  *    Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  26  * THE SOFTWARE.
  27  */
  28
  29 #include "qemu/osdep.h"
  30 #include "nbd-client.h"
  31 #include "block/qdict.h"
  32 #include "qapi/error.h"
  33 #include "qemu/uri.h"
  34 #include "block/block_int.h"
  35 #include "qemu/module.h"
  36 #include "qemu/option.h"
  37 #include "qapi/qapi-visit-sockets.h"
  38 #include "qapi/qobject-input-visitor.h"
  39 #include "qapi/qobject-output-visitor.h"
  40 #include "qapi/qmp/qdict.h"
  41 #include "qapi/qmp/qstring.h"
  42 #include "qemu/cutils.h"
  43
  44 #define EN_OPTSTR ":exportname="
  45
  46 typedef struct BDRVNBDState {
  47     NBDClientSession client;
  48
  49     /* For nbd_refresh_filename() */
  50     SocketAddress *saddr;
  51     char *export, *tlscredsid;
  52 } BDRVNBDState;
  53
  54 static int nbd_parse_uri(const char *filename, QDict *options)
  55 {
  56     URI *uri;
  57     const char *p;
  58     QueryParams *qp = NULL;
  59     int ret = 0;
  60     bool is_unix;
  61
  62     uri = uri_parse(filename);
  63     if (!uri) {
  64         return -EINVAL;
  65     }
  66
  67     /* transport */
  68     if (!g_strcmp0(uri->scheme, "nbd")) {
  69         is_unix = false;
  70     } else if (!g_strcmp0(uri->scheme, "nbd+tcp")) {
  71         is_unix = false;
  72     } else if (!g_strcmp0(uri->scheme, "nbd+unix")) {
  73         is_unix = true;
  74     } else {
  75         ret = -EINVAL;
  76         goto out;
  77     }
  78
  79     p = uri->path ? uri->path : "/";
  80     p += strspn(p, "/");
  81     if (p[0]) {
  82         qdict_put_str(options, "export", p);
  83     }
  84
  85     qp = query_params_parse(uri->query);
  86     if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
  87         ret = -EINVAL;
  88         goto out;
  89     }
  90
  91     if (is_unix) {
  92         /* nbd+unix:///export?socket=path */
  93         if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
  94             ret = -EINVAL;
  95             goto out;
  96         }
  97         qdict_put_str(options, "server.type", "unix");
  98         qdict_put_str(options, "server.path", qp->p[0].value);
  99     } else {
 100         QString *host;
 101         char *port_str;
 102
 103         /* nbd[+tcp]://host[:port]/export */
 104         if (!uri->server) {
 105             ret = -EINVAL;
 106             goto out;
 107         }
 108
 109         /* strip braces from literal IPv6 address */
 110         if (uri->server[0] == '[') {
 111             host = qstring_from_substr(uri->server, 1,
 112                                        strlen(uri->server) - 1);
 113         } else {
 114             host = qstring_from_str(uri->server);
 115         }
 116
 117         qdict_put_str(options, "server.type", "inet");
 118         qdict_put(options, "server.host", host);
 119
 120         port_str = g_strdup_printf("%d", uri->port ?: NBD_DEFAULT_PORT);
 121         qdict_put_str(options, "server.port", port_str);
 122         g_free(port_str);
 123     }
 124
 125 out:
 126     if (qp) {
 127         query_params_free(qp);
 128     }
 129     uri_free(uri);
 130     return ret;
 131 }
 132
 133 static bool nbd_has_filename_options_conflict(QDict *options, Error **errp)
 134 {
 135     const QDictEntry *e;
 136
 137     for (e = qdict_first(options); e; e = qdict_next(options, e)) {
 138         if (!strcmp(e->key, "host") ||
 139             !strcmp(e->key, "port") ||
 140             !strcmp(e->key, "path") ||
 141             !strcmp(e->key, "export") ||
 142             strstart(e->key, "server.", NULL))
 143         {
 144             error_setg(errp, "Option '%s' cannot be used with a file name",
 145                        e->key);
 146             return true;
 147         }
 148     }
 149
 150     return false;
 151 }
 152
 153 static void nbd_parse_filename(const char *filename, QDict *options,
 154                                Error **errp)
 155 {
 156     char *file;
 157     char *export_name;
 158     const char *host_spec;
 159     const char *unixpath;
 160
 161     if (nbd_has_filename_options_conflict(options, errp)) {
 162         return;
 163     }
 164
 165     if (strstr(filename, "://")) {
 166         int ret = nbd_parse_uri(filename, options);
 167         if (ret < 0) {
 168             error_setg(errp, "No valid URL specified");
 169         }
 170         return;
 171     }
 172
 173     file = g_strdup(filename);
 174
 175     export_name = strstr(file, EN_OPTSTR);
 176     if (export_name) {
 177         if (export_name[strlen(EN_OPTSTR)] == 0) {
 178             goto out;
 179         }
 180         export_name[0] = 0; /* truncate 'file' */
 181         export_name += strlen(EN_OPTSTR);
 182
 183         qdict_put_str(options, "export", export_name);
 184     }
 185
 186     /* extract the host_spec - fail if it's not nbd:... */
 187     if (!strstart(file, "nbd:", &host_spec)) {
 188         error_setg(errp, "File name string for NBD must start with 'nbd:'");
 189         goto out;
 190     }
 191
 192     if (!*host_spec) {
 193         goto out;
 194     }
 195
 196     /* are we a UNIX or TCP socket? */
 197     if (strstart(host_spec, "unix:", &unixpath)) {
 198         qdict_put_str(options, "server.type", "unix");
 199         qdict_put_str(options, "server.path", unixpath);
 200     } else {
 201         InetSocketAddress *addr = g_new(InetSocketAddress, 1);
 202
 203         if (inet_parse(addr, host_spec, errp)) {
 204             goto out_inet;
 205         }
 206
 207         qdict_put_str(options, "server.type", "inet");
 208         qdict_put_str(options, "server.host", addr->host);
 209         qdict_put_str(options, "server.port", addr->port);
 210     out_inet:
 211         qapi_free_InetSocketAddress(addr);
 212     }
 213
 214 out:
 215     g_free(file);
 216 }
 217
 218 static bool nbd_process_legacy_socket_options(QDict *output_options,
 219                                               QemuOpts *legacy_opts,
 220                                               Error **errp)
 221 {
 222     const char *path = qemu_opt_get(legacy_opts, "path");
 223     const char *host = qemu_opt_get(legacy_opts, "host");
 224     const char *port = qemu_opt_get(legacy_opts, "port");
 225     const QDictEntry *e;
 226
 227     if (!path && !host && !port) {
 228         return true;
 229     }
 230
 231     for (e = qdict_first(output_options); e; e = qdict_next(output_options, e))
 232     {
 233         if (strstart(e->key, "server.", NULL)) {
 234             error_setg(errp, "Cannot use 'server' and path/host/port at the "
 235                        "same time");
 236             return false;
 237         }
 238     }
 239
 240     if (path && host) {
 241         error_setg(errp, "path and host may not be used at the same time");
 242         return false;
 243     } else if (path) {
 244         if (port) {
 245             error_setg(errp, "port may not be used without host");
 246             return false;
 247         }
 248
 249         qdict_put_str(output_options, "server.type", "unix");
 250         qdict_put_str(output_options, "server.path", path);
 251     } else if (host) {
 252         qdict_put_str(output_options, "server.type", "inet");
 253         qdict_put_str(output_options, "server.host", host);
 254         qdict_put_str(output_options, "server.port",
 255                       port ?: stringify(NBD_DEFAULT_PORT));
 256     }
 257
 258     return true;
 259 }
 260
 261 static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
 262                                  Error **errp)
 263 {
 264     SocketAddress *saddr = NULL;
 265     QDict *addr = NULL;
 266     Visitor *iv = NULL;
 267     Error *local_err = NULL;
 268
 269     qdict_extract_subqdict(options, &addr, "server.");
 270     if (!qdict_size(addr)) {
 271         error_setg(errp, "NBD server address missing");
 272         goto done;
 273     }
 274
 275     iv = qobject_input_visitor_new_flat_confused(addr, errp);
 276     if (!iv) {
 277         goto done;
 278     }
 279
 280     visit_type_SocketAddress(iv, NULL, &saddr, &local_err);
 281     if (local_err) {
 282         error_propagate(errp, local_err);
 283         goto done;
 284     }
 285
 286 done:
 287     qobject_unref(addr);
 288     visit_free(iv);
 289     return saddr;
 290 }
 291
 292 NBDClientSession *nbd_get_client_session(BlockDriverState *bs)
 293 {
 294     BDRVNBDState *s = bs->opaque;
 295     return &s->client;
 296 }
 297
 298 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 299 {
 300     Object *obj;
 301     QCryptoTLSCreds *creds;
 302
 303     obj = object_resolve_path_component(
 304         object_get_objects_root(), id);
 305     if (!obj) {
 306         error_setg(errp, "No TLS credentials with id '%s'",
 307                    id);
 308         return NULL;
 309     }
 310     creds = (QCryptoTLSCreds *)
 311         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 312     if (!creds) {
 313         error_setg(errp, "Object with id '%s' is not TLS credentials",
 314                    id);
 315         return NULL;
 316     }
 317
 318     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
 319         error_setg(errp,
 320                    "Expecting TLS credentials with a client endpoint");
 321         return NULL;
 322     }
 323     object_ref(obj);
 324     return creds;
 325 }
 326
 327
 328 static QemuOptsList nbd_runtime_opts = {
 329     .name = "nbd",
 330     .head = QTAILQ_HEAD_INITIALIZER(nbd_runtime_opts.head),
 331     .desc = {
 332         {
 333             .name = "host",
 334             .type = QEMU_OPT_STRING,
 335             .help = "TCP host to connect to",
 336         },
 337         {
 338             .name = "port",
 339             .type = QEMU_OPT_STRING,
 340             .help = "TCP port to connect to",
 341         },
 342         {
 343             .name = "path",
 344             .type = QEMU_OPT_STRING,
 345             .help = "Unix socket path to connect to",
 346         },
 347         {
 348             .name = "export",
 349             .type = QEMU_OPT_STRING,
 350             .help = "Name of the NBD export to open",
 351         },
 352         {
 353             .name = "tls-creds",
 354             .type = QEMU_OPT_STRING,
 355             .help = "ID of the TLS credentials to use",
 356         },
 357         {
 358             .name = "x-dirty-bitmap",
 359             .type = QEMU_OPT_STRING,
 360             .help = "experimental: expose named dirty bitmap in place of "
 361                     "block status",
 362         },
 363         { /* end of list */ }
 364     },
 365 };
 366
 367 static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
 368                     Error **errp)
 369 {
 370     BDRVNBDState *s = bs->opaque;
 371     QemuOpts *opts = NULL;
 372     Error *local_err = NULL;
 373     QCryptoTLSCreds *tlscreds = NULL;
 374     const char *hostname = NULL;
 375     int ret = -EINVAL;
 376
 377     opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
 378     qemu_opts_absorb_qdict(opts, options, &local_err);
 379     if (local_err) {
 380         error_propagate(errp, local_err);
 381         goto error;
 382     }
 383
 384     /* Translate @host, @port, and @path to a SocketAddress */
 385     if (!nbd_process_legacy_socket_options(options, opts, errp)) {
 386         goto error;
 387     }
 388
 389     /* Pop the config into our state object. Exit if invalid. */
 390     s->saddr = nbd_config(s, options, errp);
 391     if (!s->saddr) {
 392         goto error;
 393     }
 394
 395     s->export = g_strdup(qemu_opt_get(opts, "export"));
 396
 397     s->tlscredsid = g_strdup(qemu_opt_get(opts, "tls-creds"));
 398     if (s->tlscredsid) {
 399         tlscreds = nbd_get_tls_creds(s->tlscredsid, errp);
 400         if (!tlscreds) {
 401             goto error;
 402         }
 403
 404         /* TODO SOCKET_ADDRESS_KIND_FD where fd has AF_INET or AF_INET6 */
 405         if (s->saddr->type != SOCKET_ADDRESS_TYPE_INET) {
 406             error_setg(errp, "TLS only supported over IP sockets");
 407             goto error;
 408         }
 409         hostname = s->saddr->u.inet.host;
 410     }
 411
 412     /* NBD handshake */
 413     ret = nbd_client_init(bs, s->saddr, s->export, tlscreds, hostname,
 414                           qemu_opt_get(opts, "x-dirty-bitmap"), errp);
 415
 416  error:
 417     if (tlscreds) {
 418         object_unref(OBJECT(tlscreds));
 419     }
 420     if (ret < 0) {
 421         qapi_free_SocketAddress(s->saddr);
 422         g_free(s->export);
 423         g_free(s->tlscredsid);
 424     }
 425     qemu_opts_del(opts);
 426     return ret;
 427 }
 428
 429 static int nbd_co_flush(BlockDriverState *bs)
 430 {
 431     return nbd_client_co_flush(bs);
 432 }
 433
 434 static void nbd_refresh_limits(BlockDriverState *bs, Error **errp)
 435 {
 436     NBDClientSession *s = nbd_get_client_session(bs);
 437     uint32_t min = s->info.min_block;
 438     uint32_t max = MIN_NON_ZERO(NBD_MAX_BUFFER_SIZE, s->info.max_block);
 439
 440     /*
 441      * If the server did not advertise an alignment:
 442      * - a size that is not sector-aligned implies that an alignment
 443      *   of 1 can be used to access those tail bytes
 444      * - advertisement of block status requires an alignment of 1, so
 445      *   that we don't violate block layer constraints that block
 446      *   status is always aligned (as we can't control whether the
 447      *   server will report sub-sector extents, such as a hole at EOF
 448      *   on an unaligned POSIX file)
 449      * - otherwise, assume the server is so old that we are safer avoiding
 450      *   sub-sector requests
 451      */
 452     if (!min) {
 453         min = (!QEMU_IS_ALIGNED(s->info.size, BDRV_SECTOR_SIZE) ||
 454                s->info.base_allocation) ? 1 : BDRV_SECTOR_SIZE;
 455     }
 456
 457     bs->bl.request_alignment = min;
 458     bs->bl.max_pdiscard = max;
 459     bs->bl.max_pwrite_zeroes = max;
 460     bs->bl.max_transfer = max;
 461
 462     if (s->info.opt_block &&
 463         s->info.opt_block > bs->bl.opt_transfer) {
 464         bs->bl.opt_transfer = s->info.opt_block;
 465     }
 466 }
 467
 468 static void nbd_close(BlockDriverState *bs)
 469 {
 470     BDRVNBDState *s = bs->opaque;
 471
 472     nbd_client_close(bs);
 473
 474     qapi_free_SocketAddress(s->saddr);
 475     g_free(s->export);
 476     g_free(s->tlscredsid);
 477 }
 478
 479 static int64_t nbd_getlength(BlockDriverState *bs)
 480 {
 481     BDRVNBDState *s = bs->opaque;
 482
 483     return s->client.info.size;
 484 }
 485
 486 static void nbd_detach_aio_context(BlockDriverState *bs)
 487 {
 488     nbd_client_detach_aio_context(bs);
 489 }
 490
 491 static void nbd_attach_aio_context(BlockDriverState *bs,
 492                                    AioContext *new_context)
 493 {
 494     nbd_client_attach_aio_context(bs, new_context);
 495 }
 496
 497 static void nbd_refresh_filename(BlockDriverState *bs)
 498 {
 499     BDRVNBDState *s = bs->opaque;
 500     const char *host = NULL, *port = NULL, *path = NULL;
 501
 502     if (s->saddr->type == SOCKET_ADDRESS_TYPE_INET) {
 503         const InetSocketAddress *inet = &s->saddr->u.inet;
 504         if (!inet->has_ipv4 && !inet->has_ipv6 && !inet->has_to) {
 505             host = inet->host;
 506             port = inet->port;
 507         }
 508     } else if (s->saddr->type == SOCKET_ADDRESS_TYPE_UNIX) {
 509         path = s->saddr->u.q_unix.path;
 510     } /* else can't represent as pseudo-filename */
 511
 512     if (path && s->export) {
 513         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 514                  "nbd+unix:///%s?socket=%s", s->export, path);
 515     } else if (path && !s->export) {
 516         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 517                  "nbd+unix://?socket=%s", path);
 518     } else if (host && s->export) {
 519         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 520                  "nbd://%s:%s/%s", host, port, s->export);
 521     } else if (host && !s->export) {
 522         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 523                  "nbd://%s:%s", host, port);
 524     }
 525 }
 526
 527 static char *nbd_dirname(BlockDriverState *bs, Error **errp)
 528 {
 529     /* The generic bdrv_dirname() implementation is able to work out some
 530      * directory name for NBD nodes, but that would be wrong. So far there is no
 531      * specification for how "export paths" would work, so NBD does not have
 532      * directory names. */
 533     error_setg(errp, "Cannot generate a base directory for NBD nodes");
 534     return NULL;
 535 }
 536
 537 static const char *const nbd_strong_runtime_opts[] = {
 538     "path",
 539     "host",
 540     "port",
 541     "export",
 542     "tls-creds",
 543     "server.",
 544
 545     NULL
 546 };
 547
 548 static BlockDriver bdrv_nbd = {
 549     .format_name                = "nbd",
 550     .protocol_name              = "nbd",
 551     .instance_size              = sizeof(BDRVNBDState),
 552     .bdrv_parse_filename        = nbd_parse_filename,
 553     .bdrv_file_open             = nbd_open,
 554     .bdrv_co_preadv             = nbd_client_co_preadv,
 555     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 556     .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 557     .bdrv_close                 = nbd_close,
 558     .bdrv_co_flush_to_os        = nbd_co_flush,
 559     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 560     .bdrv_refresh_limits        = nbd_refresh_limits,
 561     .bdrv_getlength             = nbd_getlength,
 562     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 563     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 564     .bdrv_refresh_filename      = nbd_refresh_filename,
 565     .bdrv_co_block_status       = nbd_client_co_block_status,
 566     .bdrv_dirname               = nbd_dirname,
 567     .strong_runtime_opts        = nbd_strong_runtime_opts,
 568 };
 569
 570 static BlockDriver bdrv_nbd_tcp = {
 571     .format_name                = "nbd",
 572     .protocol_name              = "nbd+tcp",
 573     .instance_size              = sizeof(BDRVNBDState),
 574     .bdrv_parse_filename        = nbd_parse_filename,
 575     .bdrv_file_open             = nbd_open,
 576     .bdrv_co_preadv             = nbd_client_co_preadv,
 577     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 578     .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 579     .bdrv_close                 = nbd_close,
 580     .bdrv_co_flush_to_os        = nbd_co_flush,
 581     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 582     .bdrv_refresh_limits        = nbd_refresh_limits,
 583     .bdrv_getlength             = nbd_getlength,
 584     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 585     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 586     .bdrv_refresh_filename      = nbd_refresh_filename,
 587     .bdrv_co_block_status       = nbd_client_co_block_status,
 588     .bdrv_dirname               = nbd_dirname,
 589     .strong_runtime_opts        = nbd_strong_runtime_opts,
 590 };
 591
 592 static BlockDriver bdrv_nbd_unix = {
 593     .format_name                = "nbd",
 594     .protocol_name              = "nbd+unix",
 595     .instance_size              = sizeof(BDRVNBDState),
 596     .bdrv_parse_filename        = nbd_parse_filename,
 597     .bdrv_file_open             = nbd_open,
 598     .bdrv_co_preadv             = nbd_client_co_preadv,
 599     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 600     .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 601     .bdrv_close                 = nbd_close,
 602     .bdrv_co_flush_to_os        = nbd_co_flush,
 603     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 604     .bdrv_refresh_limits        = nbd_refresh_limits,
 605     .bdrv_getlength             = nbd_getlength,
 606     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 607     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 608     .bdrv_refresh_filename      = nbd_refresh_filename,
 609     .bdrv_co_block_status       = nbd_client_co_block_status,
 610     .bdrv_dirname               = nbd_dirname,
 611     .strong_runtime_opts        = nbd_strong_runtime_opts,
 612 };
 613
 614 static void bdrv_nbd_init(void)
 615 {
 616     bdrv_register(&bdrv_nbd);
 617     bdrv_register(&bdrv_nbd_tcp);
 618     bdrv_register(&bdrv_nbd_unix);
 619 }
 620
 621 block_init(bdrv_nbd_init);