block/raw_bsd.c

   1 /* BlockDriver implementation for "raw"
   2  *
   3  * Copyright (C) 2010-2016 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, sector_num, nb_sectors, qiov);
  58 }
  59
  60 static int coroutine_fn
  61 raw_co_writev_flags(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
  62                     QEMUIOVector *qiov, int flags)
  63 {
  64     void *buf = NULL;
  65     BlockDriver *drv;
  66     QEMUIOVector local_qiov;
  67     int ret;
  68
  69     if (bs->probed && sector_num == 0) {
  70         /* As long as these conditions are true, we can't get partial writes to
  71          * the probe buffer and can just directly check the request. */
  72         QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
  73         QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
  74
  75         if (nb_sectors == 0) {
  76             /* qemu_iovec_to_buf() would fail, but we want to return success
  77              * instead of -EINVAL in this case. */
  78             return 0;
  79         }
  80
  81         buf = qemu_try_blockalign(bs->file->bs, 512);
  82         if (!buf) {
  83             ret = -ENOMEM;
  84             goto fail;
  85         }
  86
  87         ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
  88         if (ret != 512) {
  89             ret = -EINVAL;
  90             goto fail;
  91         }
  92
  93         drv = bdrv_probe_all(buf, 512, NULL);
  94         if (drv != bs->drv) {
  95             ret = -EPERM;
  96             goto fail;
  97         }
  98
  99         /* Use the checked buffer, a malicious guest might be overwriting its
 100          * original buffer in the background. */
 101         qemu_iovec_init(&local_qiov, qiov->niov + 1);
 102         qemu_iovec_add(&local_qiov, buf, 512);
 103         qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
 104         qiov = &local_qiov;
 105     }
 106
 107     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 108     ret = bdrv_co_pwritev(bs->file, sector_num * BDRV_SECTOR_SIZE,
 109                           nb_sectors * BDRV_SECTOR_SIZE, qiov, flags);
 110
 111 fail:
 112     if (qiov == &local_qiov) {
 113         qemu_iovec_destroy(&local_qiov);
 114     }
 115     qemu_vfree(buf);
 116     return ret;
 117 }
 118
 119 static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
 120                                             int64_t sector_num,
 121                                             int nb_sectors, int *pnum,
 122                                             BlockDriverState **file)
 123 {
 124     *pnum = nb_sectors;
 125     *file = bs->file->bs;
 126     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
 127            (sector_num << BDRV_SECTOR_BITS);
 128 }
 129
 130 static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
 131                                              int64_t offset, int count,
 132                                              BdrvRequestFlags flags)
 133 {
 134     return bdrv_co_pwrite_zeroes(bs->file, offset, count, flags);
 135 }
 136
 137 static int coroutine_fn raw_co_discard(BlockDriverState *bs,
 138                                        int64_t sector_num, int nb_sectors)
 139 {
 140     return bdrv_co_discard(bs->file->bs, sector_num, nb_sectors);
 141 }
 142
 143 static int64_t raw_getlength(BlockDriverState *bs)
 144 {
 145     return bdrv_getlength(bs->file->bs);
 146 }
 147
 148 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 149 {
 150     return bdrv_get_info(bs->file->bs, bdi);
 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     return bdrv_create_file(filename, opts, errp);
 189 }
 190
 191 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 192                     Error **errp)
 193 {
 194     bs->sg = bs->file->bs->sg;
 195     bs->supported_write_flags = BDRV_REQ_FUA &
 196         bs->file->bs->supported_write_flags;
 197     bs->supported_zero_flags = (BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP) &
 198         bs->file->bs->supported_zero_flags;
 199
 200     if (bs->probed && !bdrv_is_read_only(bs)) {
 201         fprintf(stderr,
 202                 "WARNING: Image format was not specified for '%s' and probing "
 203                 "guessed raw.\n"
 204                 "         Automatically detecting the format is dangerous for "
 205                 "raw images, write operations on block 0 will be restricted.\n"
 206                 "         Specify the 'raw' format explicitly to remove the "
 207                 "restrictions.\n",
 208                 bs->file->bs->filename);
 209     }
 210
 211     return 0;
 212 }
 213
 214 static void raw_close(BlockDriverState *bs)
 215 {
 216 }
 217
 218 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 219 {
 220     /* smallest possible positive score so that raw is used if and only if no
 221      * other block driver works
 222      */
 223     return 1;
 224 }
 225
 226 static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
 227 {
 228     return bdrv_probe_blocksizes(bs->file->bs, bsz);
 229 }
 230
 231 static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
 232 {
 233     return bdrv_probe_geometry(bs->file->bs, geo);
 234 }
 235
 236 BlockDriver bdrv_raw = {
 237     .format_name          = "raw",
 238     .bdrv_probe           = &raw_probe,
 239     .bdrv_reopen_prepare  = &raw_reopen_prepare,
 240     .bdrv_open            = &raw_open,
 241     .bdrv_close           = &raw_close,
 242     .bdrv_create          = &raw_create,
 243     .bdrv_co_readv        = &raw_co_readv,
 244     .bdrv_co_writev_flags = &raw_co_writev_flags,
 245     .bdrv_co_pwrite_zeroes = &raw_co_pwrite_zeroes,
 246     .bdrv_co_discard      = &raw_co_discard,
 247     .bdrv_co_get_block_status = &raw_co_get_block_status,
 248     .bdrv_truncate        = &raw_truncate,
 249     .bdrv_getlength       = &raw_getlength,
 250     .has_variable_length  = true,
 251     .bdrv_get_info        = &raw_get_info,
 252     .bdrv_probe_blocksizes = &raw_probe_blocksizes,
 253     .bdrv_probe_geometry  = &raw_probe_geometry,
 254     .bdrv_media_changed   = &raw_media_changed,
 255     .bdrv_eject           = &raw_eject,
 256     .bdrv_lock_medium     = &raw_lock_medium,
 257     .bdrv_aio_ioctl       = &raw_aio_ioctl,
 258     .create_opts          = &raw_create_opts,
 259     .bdrv_has_zero_init   = &raw_has_zero_init
 260 };
 261
 262 static void bdrv_raw_init(void)
 263 {
 264     bdrv_register(&bdrv_raw);
 265 }
 266
 267 block_init(bdrv_raw_init);