block/raw-format.c

   1 /* BlockDriver implementation for "raw" format driver
   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 typedef struct BDRVRawState {
  35     uint64_t offset;
  36     uint64_t size;
  37     bool has_size;
  38 } BDRVRawState;
  39
  40 static QemuOptsList raw_runtime_opts = {
  41     .name = "raw",
  42     .head = QTAILQ_HEAD_INITIALIZER(raw_runtime_opts.head),
  43     .desc = {
  44         {
  45             .name = "offset",
  46             .type = QEMU_OPT_SIZE,
  47             .help = "offset in the disk where the image starts",
  48         },
  49         {
  50             .name = "size",
  51             .type = QEMU_OPT_SIZE,
  52             .help = "virtual disk size",
  53         },
  54         { /* end of list */ }
  55     },
  56 };
  57
  58 static QemuOptsList raw_create_opts = {
  59     .name = "raw-create-opts",
  60     .head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
  61     .desc = {
  62         {
  63             .name = BLOCK_OPT_SIZE,
  64             .type = QEMU_OPT_SIZE,
  65             .help = "Virtual disk size"
  66         },
  67         { /* end of list */ }
  68     }
  69 };
  70
  71 static int raw_read_options(QDict *options, BlockDriverState *bs,
  72     BDRVRawState *s, Error **errp)
  73 {
  74     Error *local_err = NULL;
  75     QemuOpts *opts = NULL;
  76     int64_t real_size = 0;
  77     int ret;
  78
  79     real_size = bdrv_getlength(bs->file->bs);
  80     if (real_size < 0) {
  81         error_setg_errno(errp, -real_size, "Could not get image size");
  82         return real_size;
  83     }
  84
  85     opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort);
  86     qemu_opts_absorb_qdict(opts, options, &local_err);
  87     if (local_err) {
  88         error_propagate(errp, local_err);
  89         ret = -EINVAL;
  90         goto end;
  91     }
  92
  93     s->offset = qemu_opt_get_size(opts, "offset", 0);
  94     if (s->offset > real_size) {
  95         error_setg(errp, "Offset (%" PRIu64 ") cannot be greater than "
  96             "size of the containing file (%" PRId64 ")",
  97             s->offset, real_size);
  98         ret = -EINVAL;
  99         goto end;
 100     }
 101
 102     if (qemu_opt_find(opts, "size") != NULL) {
 103         s->size = qemu_opt_get_size(opts, "size", 0);
 104         s->has_size = true;
 105     } else {
 106         s->has_size = false;
 107         s->size = real_size - s->offset;
 108     }
 109
 110     /* Check size and offset */
 111     if ((real_size - s->offset) < s->size) {
 112         error_setg(errp, "The sum of offset (%" PRIu64 ") and size "
 113             "(%" PRIu64 ") has to be smaller or equal to the "
 114             " actual size of the containing file (%" PRId64 ")",
 115             s->offset, s->size, real_size);
 116         ret = -EINVAL;
 117         goto end;
 118     }
 119
 120     /* Make sure size is multiple of BDRV_SECTOR_SIZE to prevent rounding
 121      * up and leaking out of the specified area. */
 122     if (s->has_size && !QEMU_IS_ALIGNED(s->size, BDRV_SECTOR_SIZE)) {
 123         error_setg(errp, "Specified size is not multiple of %llu",
 124             BDRV_SECTOR_SIZE);
 125         ret = -EINVAL;
 126         goto end;
 127     }
 128
 129     ret = 0;
 130
 131 end:
 132
 133     qemu_opts_del(opts);
 134
 135     return ret;
 136 }
 137
 138 static int raw_reopen_prepare(BDRVReopenState *reopen_state,
 139                               BlockReopenQueue *queue, Error **errp)
 140 {
 141     assert(reopen_state != NULL);
 142     assert(reopen_state->bs != NULL);
 143
 144     reopen_state->opaque = g_new0(BDRVRawState, 1);
 145
 146     return raw_read_options(
 147         reopen_state->options,
 148         reopen_state->bs,
 149         reopen_state->opaque,
 150         errp);
 151 }
 152
 153 static void raw_reopen_commit(BDRVReopenState *state)
 154 {
 155     BDRVRawState *new_s = state->opaque;
 156     BDRVRawState *s = state->bs->opaque;
 157
 158     memcpy(s, new_s, sizeof(BDRVRawState));
 159
 160     g_free(state->opaque);
 161     state->opaque = NULL;
 162 }
 163
 164 static void raw_reopen_abort(BDRVReopenState *state)
 165 {
 166     g_free(state->opaque);
 167     state->opaque = NULL;
 168 }
 169
 170 static int coroutine_fn raw_co_preadv(BlockDriverState *bs, uint64_t offset,
 171                                       uint64_t bytes, QEMUIOVector *qiov,
 172                                       int flags)
 173 {
 174     BDRVRawState *s = bs->opaque;
 175
 176     if (offset > UINT64_MAX - s->offset) {
 177         return -EINVAL;
 178     }
 179     offset += s->offset;
 180
 181     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 182     return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
 183 }
 184
 185 static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
 186                                        uint64_t bytes, QEMUIOVector *qiov,
 187                                        int flags)
 188 {
 189     BDRVRawState *s = bs->opaque;
 190     void *buf = NULL;
 191     BlockDriver *drv;
 192     QEMUIOVector local_qiov;
 193     int ret;
 194
 195     if (s->has_size && (offset > s->size || bytes > (s->size - offset))) {
 196         /* There's not enough space for the data. Don't write anything and just
 197          * fail to prevent leaking out of the size specified in options. */
 198         return -ENOSPC;
 199     }
 200
 201     if (offset > UINT64_MAX - s->offset) {
 202         ret = -EINVAL;
 203         goto fail;
 204     }
 205
 206     if (bs->probed && offset < BLOCK_PROBE_BUF_SIZE && bytes) {
 207         /* Handling partial writes would be a pain - so we just
 208          * require that guests have 512-byte request alignment if
 209          * probing occurred */
 210         QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
 211         QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
 212         assert(offset == 0 && bytes >= BLOCK_PROBE_BUF_SIZE);
 213
 214         buf = qemu_try_blockalign(bs->file->bs, 512);
 215         if (!buf) {
 216             ret = -ENOMEM;
 217             goto fail;
 218         }
 219
 220         ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
 221         if (ret != 512) {
 222             ret = -EINVAL;
 223             goto fail;
 224         }
 225
 226         drv = bdrv_probe_all(buf, 512, NULL);
 227         if (drv != bs->drv) {
 228             ret = -EPERM;
 229             goto fail;
 230         }
 231
 232         /* Use the checked buffer, a malicious guest might be overwriting its
 233          * original buffer in the background. */
 234         qemu_iovec_init(&local_qiov, qiov->niov + 1);
 235         qemu_iovec_add(&local_qiov, buf, 512);
 236         qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
 237         qiov = &local_qiov;
 238     }
 239
 240     offset += s->offset;
 241
 242     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 243     ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
 244
 245 fail:
 246     if (qiov == &local_qiov) {
 247         qemu_iovec_destroy(&local_qiov);
 248     }
 249     qemu_vfree(buf);
 250     return ret;
 251 }
 252
 253 static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
 254                                             int64_t sector_num,
 255                                             int nb_sectors, int *pnum,
 256                                             BlockDriverState **file)
 257 {
 258     BDRVRawState *s = bs->opaque;
 259     *pnum = nb_sectors;
 260     *file = bs->file->bs;
 261     sector_num += s->offset / BDRV_SECTOR_SIZE;
 262     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
 263            (sector_num << BDRV_SECTOR_BITS);
 264 }
 265
 266 static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
 267                                              int64_t offset, int count,
 268                                              BdrvRequestFlags flags)
 269 {
 270     BDRVRawState *s = bs->opaque;
 271     if (offset > UINT64_MAX - s->offset) {
 272         return -EINVAL;
 273     }
 274     offset += s->offset;
 275     return bdrv_co_pwrite_zeroes(bs->file, offset, count, flags);
 276 }
 277
 278 static int coroutine_fn raw_co_pdiscard(BlockDriverState *bs,
 279                                         int64_t offset, int count)
 280 {
 281     BDRVRawState *s = bs->opaque;
 282     if (offset > UINT64_MAX - s->offset) {
 283         return -EINVAL;
 284     }
 285     offset += s->offset;
 286     return bdrv_co_pdiscard(bs->file->bs, offset, count);
 287 }
 288
 289 static int64_t raw_getlength(BlockDriverState *bs)
 290 {
 291     int64_t len;
 292     BDRVRawState *s = bs->opaque;
 293
 294     /* Update size. It should not change unless the file was externally
 295      * modified. */
 296     len = bdrv_getlength(bs->file->bs);
 297     if (len < 0) {
 298         return len;
 299     }
 300
 301     if (len < s->offset) {
 302         s->size = 0;
 303     } else {
 304         if (s->has_size) {
 305             /* Try to honour the size */
 306             s->size = MIN(s->size, len - s->offset);
 307         } else {
 308             s->size = len - s->offset;
 309         }
 310     }
 311
 312     return s->size;
 313 }
 314
 315 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 316 {
 317     return bdrv_get_info(bs->file->bs, bdi);
 318 }
 319
 320 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 321 {
 322     if (bs->probed) {
 323         /* To make it easier to protect the first sector, any probed
 324          * image is restricted to read-modify-write on sub-sector
 325          * operations. */
 326         bs->bl.request_alignment = BDRV_SECTOR_SIZE;
 327     }
 328 }
 329
 330 static int raw_truncate(BlockDriverState *bs, int64_t offset)
 331 {
 332     BDRVRawState *s = bs->opaque;
 333
 334     if (s->has_size) {
 335         return -ENOTSUP;
 336     }
 337
 338     if (INT64_MAX - offset < s->offset) {
 339         return -EINVAL;
 340     }
 341
 342     s->size = offset;
 343     offset += s->offset;
 344     return bdrv_truncate(bs->file, offset, NULL);
 345 }
 346
 347 static int raw_media_changed(BlockDriverState *bs)
 348 {
 349     return bdrv_media_changed(bs->file->bs);
 350 }
 351
 352 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 353 {
 354     bdrv_eject(bs->file->bs, eject_flag);
 355 }
 356
 357 static void raw_lock_medium(BlockDriverState *bs, bool locked)
 358 {
 359     bdrv_lock_medium(bs->file->bs, locked);
 360 }
 361
 362 static int raw_co_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
 363 {
 364     BDRVRawState *s = bs->opaque;
 365     if (s->offset || s->has_size) {
 366         return -ENOTSUP;
 367     }
 368     return bdrv_co_ioctl(bs->file->bs, req, buf);
 369 }
 370
 371 static int raw_has_zero_init(BlockDriverState *bs)
 372 {
 373     return bdrv_has_zero_init(bs->file->bs);
 374 }
 375
 376 static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
 377 {
 378     return bdrv_create_file(filename, opts, errp);
 379 }
 380
 381 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 382                     Error **errp)
 383 {
 384     BDRVRawState *s = bs->opaque;
 385     int ret;
 386
 387     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
 388                                false, errp);
 389     if (!bs->file) {
 390         return -EINVAL;
 391     }
 392
 393     bs->sg = bs->file->bs->sg;
 394     bs->supported_write_flags = BDRV_REQ_FUA &
 395         bs->file->bs->supported_write_flags;
 396     bs->supported_zero_flags = (BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP) &
 397         bs->file->bs->supported_zero_flags;
 398
 399     if (bs->probed && !bdrv_is_read_only(bs)) {
 400         fprintf(stderr,
 401                 "WARNING: Image format was not specified for '%s' and probing "
 402                 "guessed raw.\n"
 403                 "         Automatically detecting the format is dangerous for "
 404                 "raw images, write operations on block 0 will be restricted.\n"
 405                 "         Specify the 'raw' format explicitly to remove the "
 406                 "restrictions.\n",
 407                 bs->file->bs->filename);
 408     }
 409
 410     ret = raw_read_options(options, bs, s, errp);
 411     if (ret < 0) {
 412         return ret;
 413     }
 414
 415     if (bs->sg && (s->offset || s->has_size)) {
 416         error_setg(errp, "Cannot use offset/size with SCSI generic devices");
 417         return -EINVAL;
 418     }
 419
 420     return 0;
 421 }
 422
 423 static void raw_close(BlockDriverState *bs)
 424 {
 425 }
 426
 427 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 428 {
 429     /* smallest possible positive score so that raw is used if and only if no
 430      * other block driver works
 431      */
 432     return 1;
 433 }
 434
 435 static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
 436 {
 437     BDRVRawState *s = bs->opaque;
 438     int ret;
 439
 440     ret = bdrv_probe_blocksizes(bs->file->bs, bsz);
 441     if (ret < 0) {
 442         return ret;
 443     }
 444
 445     if (!QEMU_IS_ALIGNED(s->offset, MAX(bsz->log, bsz->phys))) {
 446         return -ENOTSUP;
 447     }
 448
 449     return 0;
 450 }
 451
 452 static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
 453 {
 454     BDRVRawState *s = bs->opaque;
 455     if (s->offset || s->has_size) {
 456         return -ENOTSUP;
 457     }
 458     return bdrv_probe_geometry(bs->file->bs, geo);
 459 }
 460
 461 BlockDriver bdrv_raw = {
 462     .format_name          = "raw",
 463     .instance_size        = sizeof(BDRVRawState),
 464     .bdrv_probe           = &raw_probe,
 465     .bdrv_reopen_prepare  = &raw_reopen_prepare,
 466     .bdrv_reopen_commit   = &raw_reopen_commit,
 467     .bdrv_reopen_abort    = &raw_reopen_abort,
 468     .bdrv_open            = &raw_open,
 469     .bdrv_close           = &raw_close,
 470     .bdrv_child_perm      = bdrv_filter_default_perms,
 471     .bdrv_create          = &raw_create,
 472     .bdrv_co_preadv       = &raw_co_preadv,
 473     .bdrv_co_pwritev      = &raw_co_pwritev,
 474     .bdrv_co_pwrite_zeroes = &raw_co_pwrite_zeroes,
 475     .bdrv_co_pdiscard     = &raw_co_pdiscard,
 476     .bdrv_co_get_block_status = &raw_co_get_block_status,
 477     .bdrv_truncate        = &raw_truncate,
 478     .bdrv_getlength       = &raw_getlength,
 479     .has_variable_length  = true,
 480     .bdrv_get_info        = &raw_get_info,
 481     .bdrv_refresh_limits  = &raw_refresh_limits,
 482     .bdrv_probe_blocksizes = &raw_probe_blocksizes,
 483     .bdrv_probe_geometry  = &raw_probe_geometry,
 484     .bdrv_media_changed   = &raw_media_changed,
 485     .bdrv_eject           = &raw_eject,
 486     .bdrv_lock_medium     = &raw_lock_medium,
 487     .bdrv_co_ioctl        = &raw_co_ioctl,
 488     .create_opts          = &raw_create_opts,
 489     .bdrv_has_zero_init   = &raw_has_zero_init
 490 };
 491
 492 static void bdrv_raw_init(void)
 493 {
 494     bdrv_register(&bdrv_raw);
 495 }
 496
 497 block_init(bdrv_raw_init);