block/raw_bsd.c

   1 /* BlockDriver implementation for "raw"
   2  *
   3  * Copyright (C) 2010, 2013, Red Hat, Inc.
   4  * Copyright (C) 2010, Blue Swirl <blauwirbel@gmail.com>
   5  * Copyright (C) 2009, Anthony Liguori <aliguori@us.ibm.com>
   6  *
   7  * Author:
   8  *   Laszlo Ersek <lersek@redhat.com>
   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
  12  * deal in the Software without restriction, including without limitation the
  13  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  14  * sell 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 THE
  23  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  25  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  26  * IN THE SOFTWARE.
  27  */
  28
  29 #include "block/block_int.h"
  30 #include "qemu/option.h"
  31
  32 static QemuOptsList raw_create_opts = {
  33     .name = "raw-create-opts",
  34     .head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
  35     .desc = {
  36         {
  37             .name = BLOCK_OPT_SIZE,
  38             .type = QEMU_OPT_SIZE,
  39             .help = "Virtual disk size"
  40         },
  41         { /* end of list */ }
  42     }
  43 };
  44
  45 static int raw_reopen_prepare(BDRVReopenState *reopen_state,
  46                               BlockReopenQueue *queue, Error **errp)
  47 {
  48     return 0;
  49 }
  50
  51 static int coroutine_fn raw_co_readv(BlockDriverState *bs, int64_t sector_num,
  52                                      int nb_sectors, QEMUIOVector *qiov)
  53 {
  54     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
  55     return bdrv_co_readv(bs->file, sector_num, nb_sectors, qiov);
  56 }
  57
  58 static int coroutine_fn raw_co_writev(BlockDriverState *bs, int64_t sector_num,
  59                                       int nb_sectors, QEMUIOVector *qiov)
  60 {
  61     void *buf = NULL;
  62     BlockDriver *drv;
  63     QEMUIOVector local_qiov;
  64     int ret;
  65
  66     if (bs->probed && sector_num == 0) {
  67         /* As long as these conditions are true, we can't get partial writes to
  68          * the probe buffer and can just directly check the request. */
  69         QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
  70         QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
  71
  72         if (nb_sectors == 0) {
  73             /* qemu_iovec_to_buf() would fail, but we want to return success
  74              * instead of -EINVAL in this case. */
  75             return 0;
  76         }
  77
  78         buf = qemu_try_blockalign(bs->file, 512);
  79         if (!buf) {
  80             ret = -ENOMEM;
  81             goto fail;
  82         }
  83
  84         ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
  85         if (ret != 512) {
  86             ret = -EINVAL;
  87             goto fail;
  88         }
  89
  90         drv = bdrv_probe_all(buf, 512, NULL);
  91         if (drv != bs->drv) {
  92             ret = -EPERM;
  93             goto fail;
  94         }
  95
  96         /* Use the checked buffer, a malicious guest might be overwriting its
  97          * original buffer in the background. */
  98         qemu_iovec_init(&local_qiov, qiov->niov + 1);
  99         qemu_iovec_add(&local_qiov, buf, 512);
 100         qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
 101         qiov = &local_qiov;
 102     }
 103
 104     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 105     ret = bdrv_co_writev(bs->file, sector_num, nb_sectors, qiov);
 106
 107 fail:
 108     if (qiov == &local_qiov) {
 109         qemu_iovec_destroy(&local_qiov);
 110     }
 111     qemu_vfree(buf);
 112     return ret;
 113 }
 114
 115 static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
 116                                             int64_t sector_num,
 117                                             int nb_sectors, int *pnum)
 118 {
 119     *pnum = nb_sectors;
 120     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
 121            (sector_num << BDRV_SECTOR_BITS);
 122 }
 123
 124 static int coroutine_fn raw_co_write_zeroes(BlockDriverState *bs,
 125                                             int64_t sector_num, int nb_sectors,
 126                                             BdrvRequestFlags flags)
 127 {
 128     return bdrv_co_write_zeroes(bs->file, sector_num, nb_sectors, flags);
 129 }
 130
 131 static int coroutine_fn raw_co_discard(BlockDriverState *bs,
 132                                        int64_t sector_num, int nb_sectors)
 133 {
 134     return bdrv_co_discard(bs->file, sector_num, nb_sectors);
 135 }
 136
 137 static int64_t raw_getlength(BlockDriverState *bs)
 138 {
 139     return bdrv_getlength(bs->file);
 140 }
 141
 142 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 143 {
 144     return bdrv_get_info(bs->file, bdi);
 145 }
 146
 147 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 148 {
 149     bs->bl = bs->file->bl;
 150 }
 151
 152 static int raw_truncate(BlockDriverState *bs, int64_t offset)
 153 {
 154     return bdrv_truncate(bs->file, offset);
 155 }
 156
 157 static int raw_is_inserted(BlockDriverState *bs)
 158 {
 159     return bdrv_is_inserted(bs->file);
 160 }
 161
 162 static int raw_media_changed(BlockDriverState *bs)
 163 {
 164     return bdrv_media_changed(bs->file);
 165 }
 166
 167 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 168 {
 169     bdrv_eject(bs->file, eject_flag);
 170 }
 171
 172 static void raw_lock_medium(BlockDriverState *bs, bool locked)
 173 {
 174     bdrv_lock_medium(bs->file, locked);
 175 }
 176
 177 static int raw_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
 178 {
 179     return bdrv_ioctl(bs->file, req, buf);
 180 }
 181
 182 static BlockAIOCB *raw_aio_ioctl(BlockDriverState *bs,
 183                                  unsigned long int req, void *buf,
 184                                  BlockCompletionFunc *cb,
 185                                  void *opaque)
 186 {
 187     return bdrv_aio_ioctl(bs->file, req, buf, cb, opaque);
 188 }
 189
 190 static int raw_has_zero_init(BlockDriverState *bs)
 191 {
 192     return bdrv_has_zero_init(bs->file);
 193 }
 194
 195 static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
 196 {
 197     Error *local_err = NULL;
 198     int ret;
 199
 200     ret = bdrv_create_file(filename, opts, &local_err);
 201     if (local_err) {
 202         error_propagate(errp, local_err);
 203     }
 204     return ret;
 205 }
 206
 207 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 208                     Error **errp)
 209 {
 210     bs->sg = bs->file->sg;
 211
 212     if (bs->probed && !bdrv_is_read_only(bs)) {
 213         fprintf(stderr,
 214                 "WARNING: Image format was not specified for '%s' and probing "
 215                 "guessed raw.\n"
 216                 "         Automatically detecting the format is dangerous for "
 217                 "raw images, write operations on block 0 will be restricted.\n"
 218                 "         Specify the 'raw' format explicitly to remove the "
 219                 "restrictions.\n",
 220                 bs->file->filename);
 221     }
 222
 223     return 0;
 224 }
 225
 226 static void raw_close(BlockDriverState *bs)
 227 {
 228 }
 229
 230 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 231 {
 232     /* smallest possible positive score so that raw is used if and only if no
 233      * other block driver works
 234      */
 235     return 1;
 236 }
 237
 238 static BlockDriver bdrv_raw = {
 239     .format_name          = "raw",
 240     .bdrv_probe           = &raw_probe,
 241     .bdrv_reopen_prepare  = &raw_reopen_prepare,
 242     .bdrv_open            = &raw_open,
 243     .bdrv_close           = &raw_close,
 244     .bdrv_create          = &raw_create,
 245     .bdrv_co_readv        = &raw_co_readv,
 246     .bdrv_co_writev       = &raw_co_writev,
 247     .bdrv_co_write_zeroes = &raw_co_write_zeroes,
 248     .bdrv_co_discard      = &raw_co_discard,
 249     .bdrv_co_get_block_status = &raw_co_get_block_status,
 250     .bdrv_truncate        = &raw_truncate,
 251     .bdrv_getlength       = &raw_getlength,
 252     .has_variable_length  = true,
 253     .bdrv_get_info        = &raw_get_info,
 254     .bdrv_refresh_limits  = &raw_refresh_limits,
 255     .bdrv_is_inserted     = &raw_is_inserted,
 256     .bdrv_media_changed   = &raw_media_changed,
 257     .bdrv_eject           = &raw_eject,
 258     .bdrv_lock_medium     = &raw_lock_medium,
 259     .bdrv_ioctl           = &raw_ioctl,
 260     .bdrv_aio_ioctl       = &raw_aio_ioctl,
 261     .create_opts          = &raw_create_opts,
 262     .bdrv_has_zero_init   = &raw_has_zero_init
 263 };
 264
 265 static void bdrv_raw_init(void)
 266 {
 267     bdrv_register(&bdrv_raw);
 268 }
 269
 270 block_init(bdrv_raw_init);