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 {
 120     *pnum = nb_sectors;
 121     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
 122            (sector_num << BDRV_SECTOR_BITS);
 123 }
 124
 125 static int coroutine_fn raw_co_write_zeroes(BlockDriverState *bs,
 126                                             int64_t sector_num, int nb_sectors,
 127                                             BdrvRequestFlags flags)
 128 {
 129     return bdrv_co_write_zeroes(bs->file->bs, sector_num, nb_sectors, flags);
 130 }
 131
 132 static int coroutine_fn raw_co_discard(BlockDriverState *bs,
 133                                        int64_t sector_num, int nb_sectors)
 134 {
 135     return bdrv_co_discard(bs->file->bs, sector_num, nb_sectors);
 136 }
 137
 138 static int64_t raw_getlength(BlockDriverState *bs)
 139 {
 140     return bdrv_getlength(bs->file->bs);
 141 }
 142
 143 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 144 {
 145     return bdrv_get_info(bs->file->bs, bdi);
 146 }
 147
 148 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 149 {
 150     bs->bl = bs->file->bs->bl;
 151 }
 152
 153 static int raw_truncate(BlockDriverState *bs, int64_t offset)
 154 {
 155     return bdrv_truncate(bs->file->bs, offset);
 156 }
 157
 158 static int raw_media_changed(BlockDriverState *bs)
 159 {
 160     return bdrv_media_changed(bs->file->bs);
 161 }
 162
 163 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 164 {
 165     bdrv_eject(bs->file->bs, eject_flag);
 166 }
 167
 168 static void raw_lock_medium(BlockDriverState *bs, bool locked)
 169 {
 170     bdrv_lock_medium(bs->file->bs, locked);
 171 }
 172
 173 static BlockAIOCB *raw_aio_ioctl(BlockDriverState *bs,
 174                                  unsigned long int req, void *buf,
 175                                  BlockCompletionFunc *cb,
 176                                  void *opaque)
 177 {
 178     return bdrv_aio_ioctl(bs->file->bs, req, buf, cb, opaque);
 179 }
 180
 181 static int raw_has_zero_init(BlockDriverState *bs)
 182 {
 183     return bdrv_has_zero_init(bs->file->bs);
 184 }
 185
 186 static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
 187 {
 188     Error *local_err = NULL;
 189     int ret;
 190
 191     ret = bdrv_create_file(filename, opts, &local_err);
 192     if (local_err) {
 193         error_propagate(errp, local_err);
 194     }
 195     return ret;
 196 }
 197
 198 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 199                     Error **errp)
 200 {
 201     bs->sg = bs->file->bs->sg;
 202
 203     if (bs->probed && !bdrv_is_read_only(bs)) {
 204         fprintf(stderr,
 205                 "WARNING: Image format was not specified for '%s' and probing "
 206                 "guessed raw.\n"
 207                 "         Automatically detecting the format is dangerous for "
 208                 "raw images, write operations on block 0 will be restricted.\n"
 209                 "         Specify the 'raw' format explicitly to remove the "
 210                 "restrictions.\n",
 211                 bs->file->bs->filename);
 212     }
 213
 214     return 0;
 215 }
 216
 217 static void raw_close(BlockDriverState *bs)
 218 {
 219 }
 220
 221 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 222 {
 223     /* smallest possible positive score so that raw is used if and only if no
 224      * other block driver works
 225      */
 226     return 1;
 227 }
 228
 229 static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
 230 {
 231     return bdrv_probe_blocksizes(bs->file->bs, bsz);
 232 }
 233
 234 static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
 235 {
 236     return bdrv_probe_geometry(bs->file->bs, geo);
 237 }
 238
 239 BlockDriver bdrv_raw = {
 240     .format_name          = "raw",
 241     .bdrv_probe           = &raw_probe,
 242     .bdrv_reopen_prepare  = &raw_reopen_prepare,
 243     .bdrv_open            = &raw_open,
 244     .bdrv_close           = &raw_close,
 245     .bdrv_create          = &raw_create,
 246     .bdrv_co_readv        = &raw_co_readv,
 247     .bdrv_co_writev       = &raw_co_writev,
 248     .bdrv_co_write_zeroes = &raw_co_write_zeroes,
 249     .bdrv_co_discard      = &raw_co_discard,
 250     .bdrv_co_get_block_status = &raw_co_get_block_status,
 251     .bdrv_truncate        = &raw_truncate,
 252     .bdrv_getlength       = &raw_getlength,
 253     .has_variable_length  = true,
 254     .bdrv_get_info        = &raw_get_info,
 255     .bdrv_refresh_limits  = &raw_refresh_limits,
 256     .bdrv_probe_blocksizes = &raw_probe_blocksizes,
 257     .bdrv_probe_geometry  = &raw_probe_geometry,
 258     .bdrv_media_changed   = &raw_media_changed,
 259     .bdrv_eject           = &raw_eject,
 260     .bdrv_lock_medium     = &raw_lock_medium,
 261     .bdrv_aio_ioctl       = &raw_aio_ioctl,
 262     .create_opts          = &raw_create_opts,
 263     .bdrv_has_zero_init   = &raw_has_zero_init
 264 };
 265
 266 static void bdrv_raw_init(void)
 267 {
 268     bdrv_register(&bdrv_raw);
 269 }
 270
 271 block_init(bdrv_raw_init);