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_preadv(BlockDriverState *bs, uint64_t offset,
  54                                       uint64_t bytes, QEMUIOVector *qiov,
  55                                       int flags)
  56 {
  57     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
  58     return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
  59 }
  60
  61 static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
  62                                        uint64_t bytes, QEMUIOVector *qiov,
  63                                        int flags)
  64 {
  65     void *buf = NULL;
  66     BlockDriver *drv;
  67     QEMUIOVector local_qiov;
  68     int ret;
  69
  70     if (bs->probed && offset < BLOCK_PROBE_BUF_SIZE && bytes) {
  71         /* Handling partial writes would be a pain - so we just
  72          * require that guests have 512-byte request alignment if
  73          * probing occurred */
  74         QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
  75         QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
  76         assert(offset == 0 && bytes >= BLOCK_PROBE_BUF_SIZE);
  77
  78         buf = qemu_try_blockalign(bs->file->bs, 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_pwritev(bs->file, offset, bytes, qiov, flags);
 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                                             BlockDriverState **file)
 119 {
 120     *pnum = nb_sectors;
 121     *file = bs->file->bs;
 122     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
 123            (sector_num << BDRV_SECTOR_BITS);
 124 }
 125
 126 static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
 127                                              int64_t offset, int count,
 128                                              BdrvRequestFlags flags)
 129 {
 130     return bdrv_co_pwrite_zeroes(bs->file, offset, count, flags);
 131 }
 132
 133 static int coroutine_fn raw_co_pdiscard(BlockDriverState *bs,
 134                                         int64_t offset, int count)
 135 {
 136     return bdrv_co_pdiscard(bs->file->bs, offset, count);
 137 }
 138
 139 static int64_t raw_getlength(BlockDriverState *bs)
 140 {
 141     return bdrv_getlength(bs->file->bs);
 142 }
 143
 144 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 145 {
 146     return bdrv_get_info(bs->file->bs, bdi);
 147 }
 148
 149 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 150 {
 151     if (bs->probed) {
 152         /* To make it easier to protect the first sector, any probed
 153          * image is restricted to read-modify-write on sub-sector
 154          * operations. */
 155         bs->bl.request_alignment = BDRV_SECTOR_SIZE;
 156     }
 157 }
 158
 159 static int raw_truncate(BlockDriverState *bs, int64_t offset)
 160 {
 161     return bdrv_truncate(bs->file->bs, offset);
 162 }
 163
 164 static int raw_media_changed(BlockDriverState *bs)
 165 {
 166     return bdrv_media_changed(bs->file->bs);
 167 }
 168
 169 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 170 {
 171     bdrv_eject(bs->file->bs, eject_flag);
 172 }
 173
 174 static void raw_lock_medium(BlockDriverState *bs, bool locked)
 175 {
 176     bdrv_lock_medium(bs->file->bs, locked);
 177 }
 178
 179 static BlockAIOCB *raw_aio_ioctl(BlockDriverState *bs,
 180                                  unsigned long int req, void *buf,
 181                                  BlockCompletionFunc *cb,
 182                                  void *opaque)
 183 {
 184     return bdrv_aio_ioctl(bs->file->bs, req, buf, cb, opaque);
 185 }
 186
 187 static int raw_has_zero_init(BlockDriverState *bs)
 188 {
 189     return bdrv_has_zero_init(bs->file->bs);
 190 }
 191
 192 static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
 193 {
 194     return bdrv_create_file(filename, opts, errp);
 195 }
 196
 197 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 198                     Error **errp)
 199 {
 200     bs->sg = bs->file->bs->sg;
 201     bs->supported_write_flags = BDRV_REQ_FUA &
 202         bs->file->bs->supported_write_flags;
 203     bs->supported_zero_flags = (BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP) &
 204         bs->file->bs->supported_zero_flags;
 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_preadv       = &raw_co_preadv,
 250     .bdrv_co_pwritev      = &raw_co_pwritev,
 251     .bdrv_co_pwrite_zeroes = &raw_co_pwrite_zeroes,
 252     .bdrv_co_pdiscard     = &raw_co_pdiscard,
 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);