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