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 "qemu/osdep.h"
  30 #include "block/block_int.h"
  31 #include "qapi/error.h"
  32 #include "qemu/option.h"
  33
  34 static QemuOptsList raw_create_opts = {
  35     .name = "raw-create-opts",
  36     .head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
  37     .desc = {
  38         {
  39             .name = BLOCK_OPT_SIZE,
  40             .type = QEMU_OPT_SIZE,
  41             .help = "Virtual disk size"
  42         },
  43         { /* end of list */ }
  44     }
  45 };
  46
  47 static int raw_reopen_prepare(BDRVReopenState *reopen_state,
  48                               BlockReopenQueue *queue, Error **errp)
  49 {
  50     return 0;
  51 }
  52
  53 static int coroutine_fn raw_co_readv(BlockDriverState *bs, int64_t sector_num,
  54                                      int nb_sectors, QEMUIOVector *qiov)
  55 {
  56     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
  57     return bdrv_co_readv(bs->file->bs, sector_num, nb_sectors, qiov);
  58 }
  59
  60 static int coroutine_fn raw_co_writev(BlockDriverState *bs, int64_t sector_num,
  61                                       int nb_sectors, QEMUIOVector *qiov)
  62 {
  63     void *buf = NULL;
  64     BlockDriver *drv;
  65     QEMUIOVector local_qiov;
  66     int ret;
  67
  68     if (bs->probed && sector_num == 0) {
  69         /* As long as these conditions are true, we can't get partial writes to
  70          * the probe buffer and can just directly check the request. */
  71         QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
  72         QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
  73
  74         if (nb_sectors == 0) {
  75             /* qemu_iovec_to_buf() would fail, but we want to return success
  76              * instead of -EINVAL in this case. */
  77             return 0;
  78         }
  79
  80         buf = qemu_try_blockalign(bs->file->bs, 512);
  81         if (!buf) {
  82             ret = -ENOMEM;
  83             goto fail;
  84         }
  85
  86         ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
  87         if (ret != 512) {
  88             ret = -EINVAL;
  89             goto fail;
  90         }
  91
  92         drv = bdrv_probe_all(buf, 512, NULL);
  93         if (drv != bs->drv) {
  94             ret = -EPERM;
  95             goto fail;
  96         }
  97
  98         /* Use the checked buffer, a malicious guest might be overwriting its
  99          * original buffer in the background. */
 100         qemu_iovec_init(&local_qiov, qiov->niov + 1);
 101         qemu_iovec_add(&local_qiov, buf, 512);
 102         qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
 103         qiov = &local_qiov;
 104     }
 105
 106     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 107     ret = bdrv_co_writev(bs->file->bs, sector_num, nb_sectors, qiov);
 108
 109 fail:
 110     if (qiov == &local_qiov) {
 111         qemu_iovec_destroy(&local_qiov);
 112     }
 113     qemu_vfree(buf);
 114     return ret;
 115 }
 116
 117 static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
 118                                             int64_t sector_num,
 119                                             int nb_sectors, int *pnum,
 120                                             BlockDriverState **file)
 121 {
 122     *pnum = nb_sectors;
 123     *file = bs->file->bs;
 124     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
 125            (sector_num << BDRV_SECTOR_BITS);
 126 }
 127
 128 static int coroutine_fn raw_co_write_zeroes(BlockDriverState *bs,
 129                                             int64_t sector_num, int nb_sectors,
 130                                             BdrvRequestFlags flags)
 131 {
 132     return bdrv_co_write_zeroes(bs->file->bs, sector_num, nb_sectors, flags);
 133 }
 134
 135 static int coroutine_fn raw_co_discard(BlockDriverState *bs,
 136                                        int64_t sector_num, int nb_sectors)
 137 {
 138     return bdrv_co_discard(bs->file->bs, sector_num, nb_sectors);
 139 }
 140
 141 static int64_t raw_getlength(BlockDriverState *bs)
 142 {
 143     return bdrv_getlength(bs->file->bs);
 144 }
 145
 146 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 147 {
 148     return bdrv_get_info(bs->file->bs, bdi);
 149 }
 150
 151 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 152 {
 153     bs->bl = bs->file->bs->bl;
 154 }
 155
 156 static int raw_truncate(BlockDriverState *bs, int64_t offset)
 157 {
 158     return bdrv_truncate(bs->file->bs, offset);
 159 }
 160
 161 static int raw_media_changed(BlockDriverState *bs)
 162 {
 163     return bdrv_media_changed(bs->file->bs);
 164 }
 165
 166 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 167 {
 168     bdrv_eject(bs->file->bs, eject_flag);
 169 }
 170
 171 static void raw_lock_medium(BlockDriverState *bs, bool locked)
 172 {
 173     bdrv_lock_medium(bs->file->bs, locked);
 174 }
 175
 176 static BlockAIOCB *raw_aio_ioctl(BlockDriverState *bs,
 177                                  unsigned long int req, void *buf,
 178                                  BlockCompletionFunc *cb,
 179                                  void *opaque)
 180 {
 181     return bdrv_aio_ioctl(bs->file->bs, req, buf, cb, opaque);
 182 }
 183
 184 static int raw_has_zero_init(BlockDriverState *bs)
 185 {
 186     return bdrv_has_zero_init(bs->file->bs);
 187 }
 188
 189 static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
 190 {
 191     Error *local_err = NULL;
 192     int ret;
 193
 194     ret = bdrv_create_file(filename, opts, &local_err);
 195     if (local_err) {
 196         error_propagate(errp, local_err);
 197     }
 198     return ret;
 199 }
 200
 201 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 202                     Error **errp)
 203 {
 204     bs->sg = bs->file->bs->sg;
 205
 206     if (bs->probed && !bdrv_is_read_only(bs)) {
 207         fprintf(stderr,
 208                 "WARNING: Image format was not specified for '%s' and probing "
 209                 "guessed raw.\n"
 210                 "         Automatically detecting the format is dangerous for "
 211                 "raw images, write operations on block 0 will be restricted.\n"
 212                 "         Specify the 'raw' format explicitly to remove the "
 213                 "restrictions.\n",
 214                 bs->file->bs->filename);
 215     }
 216
 217     return 0;
 218 }
 219
 220 static void raw_close(BlockDriverState *bs)
 221 {
 222 }
 223
 224 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 225 {
 226     /* smallest possible positive score so that raw is used if and only if no
 227      * other block driver works
 228      */
 229     return 1;
 230 }
 231
 232 static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
 233 {
 234     return bdrv_probe_blocksizes(bs->file->bs, bsz);
 235 }
 236
 237 static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
 238 {
 239     return bdrv_probe_geometry(bs->file->bs, geo);
 240 }
 241
 242 BlockDriver bdrv_raw = {
 243     .format_name          = "raw",
 244     .bdrv_probe           = &raw_probe,
 245     .bdrv_reopen_prepare  = &raw_reopen_prepare,
 246     .bdrv_open            = &raw_open,
 247     .bdrv_close           = &raw_close,
 248     .bdrv_create          = &raw_create,
 249     .bdrv_co_readv        = &raw_co_readv,
 250     .bdrv_co_writev       = &raw_co_writev,
 251     .bdrv_co_write_zeroes = &raw_co_write_zeroes,
 252     .bdrv_co_discard      = &raw_co_discard,
 253     .bdrv_co_get_block_status = &raw_co_get_block_status,
 254     .bdrv_truncate        = &raw_truncate,
 255     .bdrv_getlength       = &raw_getlength,
 256     .has_variable_length  = true,
 257     .bdrv_get_info        = &raw_get_info,
 258     .bdrv_refresh_limits  = &raw_refresh_limits,
 259     .bdrv_probe_blocksizes = &raw_probe_blocksizes,
 260     .bdrv_probe_geometry  = &raw_probe_geometry,
 261     .bdrv_media_changed   = &raw_media_changed,
 262     .bdrv_eject           = &raw_eject,
 263     .bdrv_lock_medium     = &raw_lock_medium,
 264     .bdrv_aio_ioctl       = &raw_aio_ioctl,
 265     .create_opts          = &raw_create_opts,
 266     .bdrv_has_zero_init   = &raw_has_zero_init
 267 };
 268
 269 static void bdrv_raw_init(void)
 270 {
 271     bdrv_register(&bdrv_raw);
 272 }
 273
 274 block_init(bdrv_raw_init);