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 "block/nbd-client.h"
  30 #include "qemu/uri.h"
  31 #include "block/block_int.h"
  32 #include "qemu/module.h"
  33 #include "qemu/sockets.h"
  34 #include "qapi/qmp/qdict.h"
  35 #include "qapi/qmp/qjson.h"
  36 #include "qapi/qmp/qint.h"
  37 #include "qapi/qmp/qstring.h"
  38
  39 #include <sys/types.h>
  40 #include <unistd.h>
  41
  42 #define EN_OPTSTR ":exportname="
  43
  44 typedef struct BDRVNBDState {
  45     NbdClientSession client;
  46     QemuOpts *socket_opts;
  47 } BDRVNBDState;
  48
  49 static int nbd_parse_uri(const char *filename, QDict *options)
  50 {
  51     URI *uri;
  52     const char *p;
  53     QueryParams *qp = NULL;
  54     int ret = 0;
  55     bool is_unix;
  56
  57     uri = uri_parse(filename);
  58     if (!uri) {
  59         return -EINVAL;
  60     }
  61
  62     /* transport */
  63     if (!strcmp(uri->scheme, "nbd")) {
  64         is_unix = false;
  65     } else if (!strcmp(uri->scheme, "nbd+tcp")) {
  66         is_unix = false;
  67     } else if (!strcmp(uri->scheme, "nbd+unix")) {
  68         is_unix = true;
  69     } else {
  70         ret = -EINVAL;
  71         goto out;
  72     }
  73
  74     p = uri->path ? uri->path : "/";
  75     p += strspn(p, "/");
  76     if (p[0]) {
  77         qdict_put(options, "export", qstring_from_str(p));
  78     }
  79
  80     qp = query_params_parse(uri->query);
  81     if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
  82         ret = -EINVAL;
  83         goto out;
  84     }
  85
  86     if (is_unix) {
  87         /* nbd+unix:///export?socket=path */
  88         if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
  89             ret = -EINVAL;
  90             goto out;
  91         }
  92         qdict_put(options, "path", qstring_from_str(qp->p[0].value));
  93     } else {
  94         QString *host;
  95         /* nbd[+tcp]://host[:port]/export */
  96         if (!uri->server) {
  97             ret = -EINVAL;
  98             goto out;
  99         }
 100
 101         /* strip braces from literal IPv6 address */
 102         if (uri->server[0] == '[') {
 103             host = qstring_from_substr(uri->server, 1,
 104                                        strlen(uri->server) - 2);
 105         } else {
 106             host = qstring_from_str(uri->server);
 107         }
 108
 109         qdict_put(options, "host", host);
 110         if (uri->port) {
 111             char* port_str = g_strdup_printf("%d", uri->port);
 112             qdict_put(options, "port", qstring_from_str(port_str));
 113             g_free(port_str);
 114         }
 115     }
 116
 117 out:
 118     if (qp) {
 119         query_params_free(qp);
 120     }
 121     uri_free(uri);
 122     return ret;
 123 }
 124
 125 static void nbd_parse_filename(const char *filename, QDict *options,
 126                                Error **errp)
 127 {
 128     char *file;
 129     char *export_name;
 130     const char *host_spec;
 131     const char *unixpath;
 132
 133     if (qdict_haskey(options, "host")
 134         || qdict_haskey(options, "port")
 135         || qdict_haskey(options, "path"))
 136     {
 137         error_setg(errp, "host/port/path and a file name may not be specified "
 138                          "at the same time");
 139         return;
 140     }
 141
 142     if (strstr(filename, "://")) {
 143         int ret = nbd_parse_uri(filename, options);
 144         if (ret < 0) {
 145             error_setg(errp, "No valid URL specified");
 146         }
 147         return;
 148     }
 149
 150     file = g_strdup(filename);
 151
 152     export_name = strstr(file, EN_OPTSTR);
 153     if (export_name) {
 154         if (export_name[strlen(EN_OPTSTR)] == 0) {
 155             goto out;
 156         }
 157         export_name[0] = 0; /* truncate 'file' */
 158         export_name += strlen(EN_OPTSTR);
 159
 160         qdict_put(options, "export", qstring_from_str(export_name));
 161     }
 162
 163     /* extract the host_spec - fail if it's not nbd:... */
 164     if (!strstart(file, "nbd:", &host_spec)) {
 165         error_setg(errp, "File name string for NBD must start with 'nbd:'");
 166         goto out;
 167     }
 168
 169     if (!*host_spec) {
 170         goto out;
 171     }
 172
 173     /* are we a UNIX or TCP socket? */
 174     if (strstart(host_spec, "unix:", &unixpath)) {
 175         qdict_put(options, "path", qstring_from_str(unixpath));
 176     } else {
 177         InetSocketAddress *addr = NULL;
 178
 179         addr = inet_parse(host_spec, errp);
 180         if (!addr) {
 181             goto out;
 182         }
 183
 184         qdict_put(options, "host", qstring_from_str(addr->host));
 185         qdict_put(options, "port", qstring_from_str(addr->port));
 186         qapi_free_InetSocketAddress(addr);
 187     }
 188
 189 out:
 190     g_free(file);
 191 }
 192
 193 static void nbd_config(BDRVNBDState *s, QDict *options, char **export,
 194                        Error **errp)
 195 {
 196     Error *local_err = NULL;
 197
 198     if (qdict_haskey(options, "path") == qdict_haskey(options, "host")) {
 199         if (qdict_haskey(options, "path")) {
 200             error_setg(errp, "path and host may not be used at the same time.");
 201         } else {
 202             error_setg(errp, "one of path and host must be specified.");
 203         }
 204         return;
 205     }
 206
 207     s->client.is_unix = qdict_haskey(options, "path");
 208     s->socket_opts = qemu_opts_create(&socket_optslist, NULL, 0,
 209                                       &error_abort);
 210
 211     qemu_opts_absorb_qdict(s->socket_opts, options, &local_err);
 212     if (local_err) {
 213         error_propagate(errp, local_err);
 214         return;
 215     }
 216
 217     if (!qemu_opt_get(s->socket_opts, "port")) {
 218         qemu_opt_set_number(s->socket_opts, "port", NBD_DEFAULT_PORT);
 219     }
 220
 221     *export = g_strdup(qdict_get_try_str(options, "export"));
 222     if (*export) {
 223         qdict_del(options, "export");
 224     }
 225 }
 226
 227 static int nbd_establish_connection(BlockDriverState *bs, Error **errp)
 228 {
 229     BDRVNBDState *s = bs->opaque;
 230     int sock;
 231
 232     if (s->client.is_unix) {
 233         sock = unix_connect_opts(s->socket_opts, errp, NULL, NULL);
 234     } else {
 235         sock = inet_connect_opts(s->socket_opts, errp, NULL, NULL);
 236         if (sock >= 0) {
 237             socket_set_nodelay(sock);
 238         }
 239     }
 240
 241     /* Failed to establish connection */
 242     if (sock < 0) {
 243         logout("Failed to establish connection to NBD server\n");
 244         return -errno;
 245     }
 246
 247     return sock;
 248 }
 249
 250 static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
 251                     Error **errp)
 252 {
 253     BDRVNBDState *s = bs->opaque;
 254     char *export = NULL;
 255     int result, sock;
 256     Error *local_err = NULL;
 257
 258     /* Pop the config into our state object. Exit if invalid. */
 259     nbd_config(s, options, &export, &local_err);
 260     if (local_err) {
 261         error_propagate(errp, local_err);
 262         return -EINVAL;
 263     }
 264
 265     /* establish TCP connection, return error if it fails
 266      * TODO: Configurable retry-until-timeout behaviour.
 267      */
 268     sock = nbd_establish_connection(bs, errp);
 269     if (sock < 0) {
 270         return sock;
 271     }
 272
 273     /* NBD handshake */
 274     result = nbd_client_session_init(&s->client, bs, sock, export);
 275     g_free(export);
 276     return result;
 277 }
 278
 279 static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num,
 280                         int nb_sectors, QEMUIOVector *qiov)
 281 {
 282     BDRVNBDState *s = bs->opaque;
 283
 284     return nbd_client_session_co_readv(&s->client, sector_num,
 285                                        nb_sectors, qiov);
 286 }
 287
 288 static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num,
 289                          int nb_sectors, QEMUIOVector *qiov)
 290 {
 291     BDRVNBDState *s = bs->opaque;
 292
 293     return nbd_client_session_co_writev(&s->client, sector_num,
 294                                         nb_sectors, qiov);
 295 }
 296
 297 static int nbd_co_flush(BlockDriverState *bs)
 298 {
 299     BDRVNBDState *s = bs->opaque;
 300
 301     return nbd_client_session_co_flush(&s->client);
 302 }
 303
 304 static int nbd_co_discard(BlockDriverState *bs, int64_t sector_num,
 305                           int nb_sectors)
 306 {
 307     BDRVNBDState *s = bs->opaque;
 308
 309     return nbd_client_session_co_discard(&s->client, sector_num,
 310                                          nb_sectors);
 311 }
 312
 313 static void nbd_close(BlockDriverState *bs)
 314 {
 315     BDRVNBDState *s = bs->opaque;
 316
 317     qemu_opts_del(s->socket_opts);
 318     nbd_client_session_close(&s->client);
 319 }
 320
 321 static int64_t nbd_getlength(BlockDriverState *bs)
 322 {
 323     BDRVNBDState *s = bs->opaque;
 324
 325     return s->client.size;
 326 }
 327
 328 static void nbd_detach_aio_context(BlockDriverState *bs)
 329 {
 330     BDRVNBDState *s = bs->opaque;
 331
 332     nbd_client_session_detach_aio_context(&s->client);
 333 }
 334
 335 static void nbd_attach_aio_context(BlockDriverState *bs,
 336                                    AioContext *new_context)
 337 {
 338     BDRVNBDState *s = bs->opaque;
 339
 340     nbd_client_session_attach_aio_context(&s->client, new_context);
 341 }
 342
 343 static void nbd_refresh_filename(BlockDriverState *bs)
 344 {
 345     QDict *opts = qdict_new();
 346     const char *path   = qdict_get_try_str(bs->options, "path");
 347     const char *host   = qdict_get_try_str(bs->options, "host");
 348     const char *port   = qdict_get_try_str(bs->options, "port");
 349     const char *export = qdict_get_try_str(bs->options, "export");
 350
 351     qdict_put_obj(opts, "driver", QOBJECT(qstring_from_str("nbd")));
 352
 353     if (path && export) {
 354         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 355                  "nbd+unix:///%s?socket=%s", export, path);
 356     } else if (path && !export) {
 357         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 358                  "nbd+unix://?socket=%s", path);
 359     } else if (!path && export && port) {
 360         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 361                  "nbd://%s:%s/%s", host, port, export);
 362     } else if (!path && export && !port) {
 363         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 364                  "nbd://%s/%s", host, export);
 365     } else if (!path && !export && port) {
 366         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 367                  "nbd://%s:%s", host, port);
 368     } else if (!path && !export && !port) {
 369         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 370                  "nbd://%s", host);
 371     }
 372
 373     if (path) {
 374         qdict_put_obj(opts, "path", QOBJECT(qstring_from_str(path)));
 375     } else if (port) {
 376         qdict_put_obj(opts, "host", QOBJECT(qstring_from_str(host)));
 377         qdict_put_obj(opts, "port", QOBJECT(qstring_from_str(port)));
 378     } else {
 379         qdict_put_obj(opts, "host", QOBJECT(qstring_from_str(host)));
 380     }
 381     if (export) {
 382         qdict_put_obj(opts, "export", QOBJECT(qstring_from_str(export)));
 383     }
 384
 385     bs->full_open_options = opts;
 386 }
 387
 388 static BlockDriver bdrv_nbd = {
 389     .format_name                = "nbd",
 390     .protocol_name              = "nbd",
 391     .instance_size              = sizeof(BDRVNBDState),
 392     .bdrv_parse_filename        = nbd_parse_filename,
 393     .bdrv_file_open             = nbd_open,
 394     .bdrv_co_readv              = nbd_co_readv,
 395     .bdrv_co_writev             = nbd_co_writev,
 396     .bdrv_close                 = nbd_close,
 397     .bdrv_co_flush_to_os        = nbd_co_flush,
 398     .bdrv_co_discard            = nbd_co_discard,
 399     .bdrv_getlength             = nbd_getlength,
 400     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 401     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 402     .bdrv_refresh_filename      = nbd_refresh_filename,
 403 };
 404
 405 static BlockDriver bdrv_nbd_tcp = {
 406     .format_name                = "nbd",
 407     .protocol_name              = "nbd+tcp",
 408     .instance_size              = sizeof(BDRVNBDState),
 409     .bdrv_parse_filename        = nbd_parse_filename,
 410     .bdrv_file_open             = nbd_open,
 411     .bdrv_co_readv              = nbd_co_readv,
 412     .bdrv_co_writev             = nbd_co_writev,
 413     .bdrv_close                 = nbd_close,
 414     .bdrv_co_flush_to_os        = nbd_co_flush,
 415     .bdrv_co_discard            = nbd_co_discard,
 416     .bdrv_getlength             = nbd_getlength,
 417     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 418     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 419     .bdrv_refresh_filename      = nbd_refresh_filename,
 420 };
 421
 422 static BlockDriver bdrv_nbd_unix = {
 423     .format_name                = "nbd",
 424     .protocol_name              = "nbd+unix",
 425     .instance_size              = sizeof(BDRVNBDState),
 426     .bdrv_parse_filename        = nbd_parse_filename,
 427     .bdrv_file_open             = nbd_open,
 428     .bdrv_co_readv              = nbd_co_readv,
 429     .bdrv_co_writev             = nbd_co_writev,
 430     .bdrv_close                 = nbd_close,
 431     .bdrv_co_flush_to_os        = nbd_co_flush,
 432     .bdrv_co_discard            = nbd_co_discard,
 433     .bdrv_getlength             = nbd_getlength,
 434     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 435     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 436     .bdrv_refresh_filename      = nbd_refresh_filename,
 437 };
 438
 439 static void bdrv_nbd_init(void)
 440 {
 441     bdrv_register(&bdrv_nbd);
 442     bdrv_register(&bdrv_nbd_tcp);
 443     bdrv_register(&bdrv_nbd_unix);
 444 }
 445
 446 block_init(bdrv_nbd_init);