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-common.h"
  30 #include "nbd.h"
  31 #include "module.h"
  32
  33 #include <sys/types.h>
  34 #include <unistd.h>
  35
  36 #define EN_OPTSTR ":exportname="
  37
  38 typedef struct BDRVNBDState {
  39     int sock;
  40     off_t size;
  41     size_t blocksize;
  42 } BDRVNBDState;
  43
  44 static int nbd_open(BlockDriverState *bs, const char* filename, int flags)
  45 {
  46     BDRVNBDState *s = bs->opaque;
  47     uint32_t nbdflags;
  48
  49     char *file;
  50     char *name;
  51     const char *host;
  52     const char *unixpath;
  53     int sock;
  54     off_t size;
  55     size_t blocksize;
  56     int ret;
  57     int err = -EINVAL;
  58
  59     file = qemu_strdup(filename);
  60
  61     name = strstr(file, EN_OPTSTR);
  62     if (name) {
  63         if (name[strlen(EN_OPTSTR)] == 0) {
  64             goto out;
  65         }
  66         name[0] = 0;
  67         name += strlen(EN_OPTSTR);
  68     }
  69
  70     if (!strstart(file, "nbd:", &host)) {
  71         goto out;
  72     }
  73
  74     if (strstart(host, "unix:", &unixpath)) {
  75
  76         if (unixpath[0] != '/') {
  77             goto out;
  78         }
  79
  80         sock = unix_socket_outgoing(unixpath);
  81
  82     } else {
  83         uint16_t port = NBD_DEFAULT_PORT;
  84         char *p, *r;
  85         char hostname[128];
  86
  87         pstrcpy(hostname, 128, host);
  88
  89         p = strchr(hostname, ':');
  90         if (p != NULL) {
  91             *p = '\0';
  92             p++;
  93
  94             port = strtol(p, &r, 0);
  95             if (r == p) {
  96                 goto out;
  97             }
  98         }
  99
 100         sock = tcp_socket_outgoing(hostname, port);
 101     }
 102
 103     if (sock == -1) {
 104         err = -errno;
 105         goto out;
 106     }
 107
 108     ret = nbd_receive_negotiate(sock, name, &nbdflags, &size, &blocksize);
 109     if (ret == -1) {
 110         err = -errno;
 111         goto out;
 112     }
 113
 114     s->sock = sock;
 115     s->size = size;
 116     s->blocksize = blocksize;
 117     err = 0;
 118
 119 out:
 120     qemu_free(file);
 121     return err;
 122 }
 123
 124 static int nbd_read(BlockDriverState *bs, int64_t sector_num,
 125                     uint8_t *buf, int nb_sectors)
 126 {
 127     BDRVNBDState *s = bs->opaque;
 128     struct nbd_request request;
 129     struct nbd_reply reply;
 130
 131     request.type = NBD_CMD_READ;
 132     request.handle = (uint64_t)(intptr_t)bs;
 133     request.from = sector_num * 512;;
 134     request.len = nb_sectors * 512;
 135
 136     if (nbd_send_request(s->sock, &request) == -1)
 137         return -errno;
 138
 139     if (nbd_receive_reply(s->sock, &reply) == -1)
 140         return -errno;
 141
 142     if (reply.error !=0)
 143         return -reply.error;
 144
 145     if (reply.handle != request.handle)
 146         return -EIO;
 147
 148     if (nbd_wr_sync(s->sock, buf, request.len, 1) != request.len)
 149         return -EIO;
 150
 151     return 0;
 152 }
 153
 154 static int nbd_write(BlockDriverState *bs, int64_t sector_num,
 155                      const uint8_t *buf, int nb_sectors)
 156 {
 157     BDRVNBDState *s = bs->opaque;
 158     struct nbd_request request;
 159     struct nbd_reply reply;
 160
 161     request.type = NBD_CMD_WRITE;
 162     request.handle = (uint64_t)(intptr_t)bs;
 163     request.from = sector_num * 512;;
 164     request.len = nb_sectors * 512;
 165
 166     if (nbd_send_request(s->sock, &request) == -1)
 167         return -errno;
 168
 169     if (nbd_wr_sync(s->sock, (uint8_t*)buf, request.len, 0) != request.len)
 170         return -EIO;
 171
 172     if (nbd_receive_reply(s->sock, &reply) == -1)
 173         return -errno;
 174
 175     if (reply.error !=0)
 176         return -reply.error;
 177
 178     if (reply.handle != request.handle)
 179         return -EIO;
 180
 181     return 0;
 182 }
 183
 184 static void nbd_close(BlockDriverState *bs)
 185 {
 186     BDRVNBDState *s = bs->opaque;
 187     struct nbd_request request;
 188
 189     request.type = NBD_CMD_DISC;
 190     request.handle = (uint64_t)(intptr_t)bs;
 191     request.from = 0;
 192     request.len = 0;
 193     nbd_send_request(s->sock, &request);
 194
 195     close(s->sock);
 196 }
 197
 198 static int64_t nbd_getlength(BlockDriverState *bs)
 199 {
 200     BDRVNBDState *s = bs->opaque;
 201
 202     return s->size;
 203 }
 204
 205 static BlockDriver bdrv_nbd = {
 206     .format_name        = "nbd",
 207     .instance_size      = sizeof(BDRVNBDState),
 208     .bdrv_file_open     = nbd_open,
 209     .bdrv_read          = nbd_read,
 210     .bdrv_write         = nbd_write,
 211     .bdrv_close         = nbd_close,
 212     .bdrv_getlength     = nbd_getlength,
 213     .protocol_name      = "nbd",
 214 };
 215
 216 static void bdrv_nbd_init(void)
 217 {
 218     bdrv_register(&bdrv_nbd);
 219 }
 220
 221 block_init(bdrv_nbd_init);