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/qjson.h"
  35 #include "qapi/qmp/qint.h"
  36
  37 #include <sys/types.h>
  38 #include <unistd.h>
  39
  40 #define EN_OPTSTR ":exportname="
  41
  42 typedef struct BDRVNBDState {
  43     NbdClientSession client;
  44     QemuOpts *socket_opts;
  45 } BDRVNBDState;
  46
  47 static int nbd_parse_uri(const char *filename, QDict *options)
  48 {
  49     URI *uri;
  50     const char *p;
  51     QueryParams *qp = NULL;
  52     int ret = 0;
  53     bool is_unix;
  54
  55     uri = uri_parse(filename);
  56     if (!uri) {
  57         return -EINVAL;
  58     }
  59
  60     /* transport */
  61     if (!strcmp(uri->scheme, "nbd")) {
  62         is_unix = false;
  63     } else if (!strcmp(uri->scheme, "nbd+tcp")) {
  64         is_unix = false;
  65     } else if (!strcmp(uri->scheme, "nbd+unix")) {
  66         is_unix = true;
  67     } else {
  68         ret = -EINVAL;
  69         goto out;
  70     }
  71
  72     p = uri->path ? uri->path : "/";
  73     p += strspn(p, "/");
  74     if (p[0]) {
  75         qdict_put(options, "export", qstring_from_str(p));
  76     }
  77
  78     qp = query_params_parse(uri->query);
  79     if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
  80         ret = -EINVAL;
  81         goto out;
  82     }
  83
  84     if (is_unix) {
  85         /* nbd+unix:///export?socket=path */
  86         if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
  87             ret = -EINVAL;
  88             goto out;
  89         }
  90         qdict_put(options, "path", qstring_from_str(qp->p[0].value));
  91     } else {
  92         QString *host;
  93         /* nbd[+tcp]://host[:port]/export */
  94         if (!uri->server) {
  95             ret = -EINVAL;
  96             goto out;
  97         }
  98
  99         /* strip braces from literal IPv6 address */
 100         if (uri->server[0] == '[') {
 101             host = qstring_from_substr(uri->server, 1,
 102                                        strlen(uri->server) - 2);
 103         } else {
 104             host = qstring_from_str(uri->server);
 105         }
 106
 107         qdict_put(options, "host", host);
 108         if (uri->port) {
 109             char* port_str = g_strdup_printf("%d", uri->port);
 110             qdict_put(options, "port", qstring_from_str(port_str));
 111             g_free(port_str);
 112         }
 113     }
 114
 115 out:
 116     if (qp) {
 117         query_params_free(qp);
 118     }
 119     uri_free(uri);
 120     return ret;
 121 }
 122
 123 static void nbd_parse_filename(const char *filename, QDict *options,
 124                                Error **errp)
 125 {
 126     char *file;
 127     char *export_name;
 128     const char *host_spec;
 129     const char *unixpath;
 130
 131     if (qdict_haskey(options, "host")
 132         || qdict_haskey(options, "port")
 133         || qdict_haskey(options, "path"))
 134     {
 135         error_setg(errp, "host/port/path and a file name may not be specified "
 136                          "at the same time");
 137         return;
 138     }
 139
 140     if (strstr(filename, "://")) {
 141         int ret = nbd_parse_uri(filename, options);
 142         if (ret < 0) {
 143             error_setg(errp, "No valid URL specified");
 144         }
 145         return;
 146     }
 147
 148     file = g_strdup(filename);
 149
 150     export_name = strstr(file, EN_OPTSTR);
 151     if (export_name) {
 152         if (export_name[strlen(EN_OPTSTR)] == 0) {
 153             goto out;
 154         }
 155         export_name[0] = 0; /* truncate 'file' */
 156         export_name += strlen(EN_OPTSTR);
 157
 158         qdict_put(options, "export", qstring_from_str(export_name));
 159     }
 160
 161     /* extract the host_spec - fail if it's not nbd:... */
 162     if (!strstart(file, "nbd:", &host_spec)) {
 163         error_setg(errp, "File name string for NBD must start with 'nbd:'");
 164         goto out;
 165     }
 166
 167     if (!*host_spec) {
 168         goto out;
 169     }
 170
 171     /* are we a UNIX or TCP socket? */
 172     if (strstart(host_spec, "unix:", &unixpath)) {
 173         qdict_put(options, "path", qstring_from_str(unixpath));
 174     } else {
 175         InetSocketAddress *addr = NULL;
 176
 177         addr = inet_parse(host_spec, errp);
 178         if (error_is_set(errp)) {
 179             goto out;
 180         }
 181
 182         qdict_put(options, "host", qstring_from_str(addr->host));
 183         qdict_put(options, "port", qstring_from_str(addr->port));
 184         qapi_free_InetSocketAddress(addr);
 185     }
 186
 187 out:
 188     g_free(file);
 189 }
 190
 191 static int nbd_config(BDRVNBDState *s, QDict *options, char **export)
 192 {
 193     Error *local_err = NULL;
 194
 195     if (qdict_haskey(options, "path")) {
 196         if (qdict_haskey(options, "host")) {
 197             qerror_report(ERROR_CLASS_GENERIC_ERROR, "path and host may not "
 198                           "be used at the same time.");
 199             return -EINVAL;
 200         }
 201         s->client.is_unix = true;
 202     } else if (qdict_haskey(options, "host")) {
 203         s->client.is_unix = false;
 204     } else {
 205         return -EINVAL;
 206     }
 207
 208     s->socket_opts = qemu_opts_create_nofail(&socket_optslist);
 209
 210     qemu_opts_absorb_qdict(s->socket_opts, options, &local_err);
 211     if (error_is_set(&local_err)) {
 212         qerror_report_err(local_err);
 213         error_free(local_err);
 214         return -EINVAL;
 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     return 0;
 227 }
 228
 229 static int nbd_establish_connection(BlockDriverState *bs)
 230 {
 231     BDRVNBDState *s = bs->opaque;
 232     int sock;
 233
 234     if (s->client.is_unix) {
 235         sock = unix_socket_outgoing(qemu_opt_get(s->socket_opts, "path"));
 236     } else {
 237         sock = tcp_socket_outgoing_opts(s->socket_opts);
 238         if (sock >= 0) {
 239             socket_set_nodelay(sock);
 240         }
 241     }
 242
 243     /* Failed to establish connection */
 244     if (sock < 0) {
 245         logout("Failed to establish connection to NBD server\n");
 246         return -errno;
 247     }
 248
 249     return sock;
 250 }
 251
 252 static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
 253                     Error **errp)
 254 {
 255     BDRVNBDState *s = bs->opaque;
 256     char *export = NULL;
 257     int result, sock;
 258
 259     /* Pop the config into our state object. Exit if invalid. */
 260     result = nbd_config(s, options, &export);
 261     if (result != 0) {
 262         return result;
 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);
 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 BlockDriver bdrv_nbd = {
 329     .format_name         = "nbd",
 330     .protocol_name       = "nbd",
 331     .instance_size       = sizeof(BDRVNBDState),
 332     .bdrv_parse_filename = nbd_parse_filename,
 333     .bdrv_file_open      = nbd_open,
 334     .bdrv_co_readv       = nbd_co_readv,
 335     .bdrv_co_writev      = nbd_co_writev,
 336     .bdrv_close          = nbd_close,
 337     .bdrv_co_flush_to_os = nbd_co_flush,
 338     .bdrv_co_discard     = nbd_co_discard,
 339     .bdrv_getlength      = nbd_getlength,
 340 };
 341
 342 static BlockDriver bdrv_nbd_tcp = {
 343     .format_name         = "nbd",
 344     .protocol_name       = "nbd+tcp",
 345     .instance_size       = sizeof(BDRVNBDState),
 346     .bdrv_parse_filename = nbd_parse_filename,
 347     .bdrv_file_open      = nbd_open,
 348     .bdrv_co_readv       = nbd_co_readv,
 349     .bdrv_co_writev      = nbd_co_writev,
 350     .bdrv_close          = nbd_close,
 351     .bdrv_co_flush_to_os = nbd_co_flush,
 352     .bdrv_co_discard     = nbd_co_discard,
 353     .bdrv_getlength      = nbd_getlength,
 354 };
 355
 356 static BlockDriver bdrv_nbd_unix = {
 357     .format_name         = "nbd",
 358     .protocol_name       = "nbd+unix",
 359     .instance_size       = sizeof(BDRVNBDState),
 360     .bdrv_parse_filename = nbd_parse_filename,
 361     .bdrv_file_open      = nbd_open,
 362     .bdrv_co_readv       = nbd_co_readv,
 363     .bdrv_co_writev      = nbd_co_writev,
 364     .bdrv_close          = nbd_close,
 365     .bdrv_co_flush_to_os = nbd_co_flush,
 366     .bdrv_co_discard     = nbd_co_discard,
 367     .bdrv_getlength      = nbd_getlength,
 368 };
 369
 370 static void bdrv_nbd_init(void)
 371 {
 372     bdrv_register(&bdrv_nbd);
 373     bdrv_register(&bdrv_nbd_tcp);
 374     bdrv_register(&bdrv_nbd_unix);
 375 }
 376
 377 block_init(bdrv_nbd_init);