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 /* Check and adjust the offset, against 'offset' and 'size' options. */
 171 static inline int raw_adjust_offset(BlockDriverState *bs, uint64_t *offset,
 172                                     uint64_t bytes, bool is_write)
 173 {
 174     BDRVRawState *s = bs->opaque;
 175
 176     if (s->has_size && (*offset > s->size || bytes > (s->size - *offset))) {
 177         /* There's not enough space for the write, or the read request is
 178          * out-of-range. Don't read/write anything to prevent leaking out of
 179          * the size specified in options. */
 180         return is_write ? -ENOSPC : -EINVAL;
 181     }
 182
 183     if (*offset > INT64_MAX - s->offset) {
 184         return -EINVAL;
 185     }
 186     *offset += s->offset;
 187
 188     return 0;
 189 }
 190
 191 static int coroutine_fn raw_co_preadv(BlockDriverState *bs, uint64_t offset,
 192                                       uint64_t bytes, QEMUIOVector *qiov,
 193                                       int flags)
 194 {
 195     int ret;
 196
 197     ret = raw_adjust_offset(bs, &offset, bytes, false);
 198     if (ret) {
 199         return ret;
 200     }
 201
 202     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 203     return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
 204 }
 205
 206 static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
 207                                        uint64_t bytes, QEMUIOVector *qiov,
 208                                        int flags)
 209 {
 210     void *buf = NULL;
 211     BlockDriver *drv;
 212     QEMUIOVector local_qiov;
 213     int ret;
 214
 215     if (bs->probed && offset < BLOCK_PROBE_BUF_SIZE && bytes) {
 216         /* Handling partial writes would be a pain - so we just
 217          * require that guests have 512-byte request alignment if
 218          * probing occurred */
 219         QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
 220         QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
 221         assert(offset == 0 && bytes >= BLOCK_PROBE_BUF_SIZE);
 222
 223         buf = qemu_try_blockalign(bs->file->bs, 512);
 224         if (!buf) {
 225             ret = -ENOMEM;
 226             goto fail;
 227         }
 228
 229         ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
 230         if (ret != 512) {
 231             ret = -EINVAL;
 232             goto fail;
 233         }
 234
 235         drv = bdrv_probe_all(buf, 512, NULL);
 236         if (drv != bs->drv) {
 237             ret = -EPERM;
 238             goto fail;
 239         }
 240
 241         /* Use the checked buffer, a malicious guest might be overwriting its
 242          * original buffer in the background. */
 243         qemu_iovec_init(&local_qiov, qiov->niov + 1);
 244         qemu_iovec_add(&local_qiov, buf, 512);
 245         qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
 246         qiov = &local_qiov;
 247     }
 248
 249     ret = raw_adjust_offset(bs, &offset, bytes, true);
 250     if (ret) {
 251         goto fail;
 252     }
 253
 254     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 255     ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
 256
 257 fail:
 258     if (qiov == &local_qiov) {
 259         qemu_iovec_destroy(&local_qiov);
 260     }
 261     qemu_vfree(buf);
 262     return ret;
 263 }
 264
 265 static int coroutine_fn raw_co_block_status(BlockDriverState *bs,
 266                                             bool want_zero, int64_t offset,
 267                                             int64_t bytes, int64_t *pnum,
 268                                             int64_t *map,
 269                                             BlockDriverState **file)
 270 {
 271     BDRVRawState *s = bs->opaque;
 272     *pnum = bytes;
 273     *file = bs->file->bs;
 274     *map = offset + s->offset;
 275     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID;
 276 }
 277
 278 static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
 279                                              int64_t offset, int bytes,
 280                                              BdrvRequestFlags flags)
 281 {
 282     int ret;
 283
 284     ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
 285     if (ret) {
 286         return ret;
 287     }
 288     return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
 289 }
 290
 291 static int coroutine_fn raw_co_pdiscard(BlockDriverState *bs,
 292                                         int64_t offset, int bytes)
 293 {
 294     int ret;
 295
 296     ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
 297     if (ret) {
 298         return ret;
 299     }
 300     return bdrv_co_pdiscard(bs->file, offset, bytes);
 301 }
 302
 303 static int64_t raw_getlength(BlockDriverState *bs)
 304 {
 305     int64_t len;
 306     BDRVRawState *s = bs->opaque;
 307
 308     /* Update size. It should not change unless the file was externally
 309      * modified. */
 310     len = bdrv_getlength(bs->file->bs);
 311     if (len < 0) {
 312         return len;
 313     }
 314
 315     if (len < s->offset) {
 316         s->size = 0;
 317     } else {
 318         if (s->has_size) {
 319             /* Try to honour the size */
 320             s->size = MIN(s->size, len - s->offset);
 321         } else {
 322             s->size = len - s->offset;
 323         }
 324     }
 325
 326     return s->size;
 327 }
 328
 329 static BlockMeasureInfo *raw_measure(QemuOpts *opts, BlockDriverState *in_bs,
 330                                      Error **errp)
 331 {
 332     BlockMeasureInfo *info;
 333     int64_t required;
 334
 335     if (in_bs) {
 336         required = bdrv_getlength(in_bs);
 337         if (required < 0) {
 338             error_setg_errno(errp, -required, "Unable to get image size");
 339             return NULL;
 340         }
 341     } else {
 342         required = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 343                             BDRV_SECTOR_SIZE);
 344     }
 345
 346     info = g_new(BlockMeasureInfo, 1);
 347     info->required = required;
 348
 349     /* Unallocated sectors count towards the file size in raw images */
 350     info->fully_allocated = info->required;
 351     return info;
 352 }
 353
 354 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 355 {
 356     return bdrv_get_info(bs->file->bs, bdi);
 357 }
 358
 359 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 360 {
 361     if (bs->probed) {
 362         /* To make it easier to protect the first sector, any probed
 363          * image is restricted to read-modify-write on sub-sector
 364          * operations. */
 365         bs->bl.request_alignment = BDRV_SECTOR_SIZE;
 366     }
 367 }
 368
 369 static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
 370                                         PreallocMode prealloc, Error **errp)
 371 {
 372     BDRVRawState *s = bs->opaque;
 373
 374     if (s->has_size) {
 375         error_setg(errp, "Cannot resize fixed-size raw disks");
 376         return -ENOTSUP;
 377     }
 378
 379     if (INT64_MAX - offset < s->offset) {
 380         error_setg(errp, "Disk size too large for the chosen offset");
 381         return -EINVAL;
 382     }
 383
 384     s->size = offset;
 385     offset += s->offset;
 386     return bdrv_co_truncate(bs->file, offset, prealloc, errp);
 387 }
 388
 389 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 390 {
 391     bdrv_eject(bs->file->bs, eject_flag);
 392 }
 393
 394 static void raw_lock_medium(BlockDriverState *bs, bool locked)
 395 {
 396     bdrv_lock_medium(bs->file->bs, locked);
 397 }
 398
 399 static int raw_co_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
 400 {
 401     BDRVRawState *s = bs->opaque;
 402     if (s->offset || s->has_size) {
 403         return -ENOTSUP;
 404     }
 405     return bdrv_co_ioctl(bs->file->bs, req, buf);
 406 }
 407
 408 static int raw_has_zero_init(BlockDriverState *bs)
 409 {
 410     return bdrv_has_zero_init(bs->file->bs);
 411 }
 412
 413 static int coroutine_fn raw_co_create_opts(const char *filename, QemuOpts *opts,
 414                                            Error **errp)
 415 {
 416     return bdrv_create_file(filename, opts, errp);
 417 }
 418
 419 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 420                     Error **errp)
 421 {
 422     BDRVRawState *s = bs->opaque;
 423     int ret;
 424
 425     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
 426                                false, errp);
 427     if (!bs->file) {
 428         return -EINVAL;
 429     }
 430
 431     bs->sg = bs->file->bs->sg;
 432     bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
 433         (BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
 434     bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
 435         ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP) &
 436             bs->file->bs->supported_zero_flags);
 437
 438     if (bs->probed && !bdrv_is_read_only(bs)) {
 439         bdrv_refresh_filename(bs->file->bs);
 440         fprintf(stderr,
 441                 "WARNING: Image format was not specified for '%s' and probing "
 442                 "guessed raw.\n"
 443                 "         Automatically detecting the format is dangerous for "
 444                 "raw images, write operations on block 0 will be restricted.\n"
 445                 "         Specify the 'raw' format explicitly to remove the "
 446                 "restrictions.\n",
 447                 bs->file->bs->filename);
 448     }
 449
 450     ret = raw_read_options(options, bs, s, errp);
 451     if (ret < 0) {
 452         return ret;
 453     }
 454
 455     if (bs->sg && (s->offset || s->has_size)) {
 456         error_setg(errp, "Cannot use offset/size with SCSI generic devices");
 457         return -EINVAL;
 458     }
 459
 460     return 0;
 461 }
 462
 463 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 464 {
 465     /* smallest possible positive score so that raw is used if and only if no
 466      * other block driver works
 467      */
 468     return 1;
 469 }
 470
 471 static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
 472 {
 473     BDRVRawState *s = bs->opaque;
 474     int ret;
 475
 476     ret = bdrv_probe_blocksizes(bs->file->bs, bsz);
 477     if (ret < 0) {
 478         return ret;
 479     }
 480
 481     if (!QEMU_IS_ALIGNED(s->offset, MAX(bsz->log, bsz->phys))) {
 482         return -ENOTSUP;
 483     }
 484
 485     return 0;
 486 }
 487
 488 static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
 489 {
 490     BDRVRawState *s = bs->opaque;
 491     if (s->offset || s->has_size) {
 492         return -ENOTSUP;
 493     }
 494     return bdrv_probe_geometry(bs->file->bs, geo);
 495 }
 496
 497 static int coroutine_fn raw_co_copy_range_from(BlockDriverState *bs,
 498                                                BdrvChild *src,
 499                                                uint64_t src_offset,
 500                                                BdrvChild *dst,
 501                                                uint64_t dst_offset,
 502                                                uint64_t bytes,
 503                                                BdrvRequestFlags read_flags,
 504                                                BdrvRequestFlags write_flags)
 505 {
 506     int ret;
 507
 508     ret = raw_adjust_offset(bs, &src_offset, bytes, false);
 509     if (ret) {
 510         return ret;
 511     }
 512     return bdrv_co_copy_range_from(bs->file, src_offset, dst, dst_offset,
 513                                    bytes, read_flags, write_flags);
 514 }
 515
 516 static int coroutine_fn raw_co_copy_range_to(BlockDriverState *bs,
 517                                              BdrvChild *src,
 518                                              uint64_t src_offset,
 519                                              BdrvChild *dst,
 520                                              uint64_t dst_offset,
 521                                              uint64_t bytes,
 522                                              BdrvRequestFlags read_flags,
 523                                              BdrvRequestFlags write_flags)
 524 {
 525     int ret;
 526
 527     ret = raw_adjust_offset(bs, &dst_offset, bytes, true);
 528     if (ret) {
 529         return ret;
 530     }
 531     return bdrv_co_copy_range_to(src, src_offset, bs->file, dst_offset, bytes,
 532                                  read_flags, write_flags);
 533 }
 534
 535 static const char *const raw_strong_runtime_opts[] = {
 536     "offset",
 537     "size",
 538
 539     NULL
 540 };
 541
 542 BlockDriver bdrv_raw = {
 543     .format_name          = "raw",
 544     .instance_size        = sizeof(BDRVRawState),
 545     .bdrv_probe           = &raw_probe,
 546     .bdrv_reopen_prepare  = &raw_reopen_prepare,
 547     .bdrv_reopen_commit   = &raw_reopen_commit,
 548     .bdrv_reopen_abort    = &raw_reopen_abort,
 549     .bdrv_open            = &raw_open,
 550     .bdrv_child_perm      = bdrv_filter_default_perms,
 551     .bdrv_co_create_opts  = &raw_co_create_opts,
 552     .bdrv_co_preadv       = &raw_co_preadv,
 553     .bdrv_co_pwritev      = &raw_co_pwritev,
 554     .bdrv_co_pwrite_zeroes = &raw_co_pwrite_zeroes,
 555     .bdrv_co_pdiscard     = &raw_co_pdiscard,
 556     .bdrv_co_block_status = &raw_co_block_status,
 557     .bdrv_co_copy_range_from = &raw_co_copy_range_from,
 558     .bdrv_co_copy_range_to  = &raw_co_copy_range_to,
 559     .bdrv_co_truncate     = &raw_co_truncate,
 560     .bdrv_getlength       = &raw_getlength,
 561     .has_variable_length  = true,
 562     .bdrv_measure         = &raw_measure,
 563     .bdrv_get_info        = &raw_get_info,
 564     .bdrv_refresh_limits  = &raw_refresh_limits,
 565     .bdrv_probe_blocksizes = &raw_probe_blocksizes,
 566     .bdrv_probe_geometry  = &raw_probe_geometry,
 567     .bdrv_eject           = &raw_eject,
 568     .bdrv_lock_medium     = &raw_lock_medium,
 569     .bdrv_co_ioctl        = &raw_co_ioctl,
 570     .create_opts          = &raw_create_opts,
 571     .bdrv_has_zero_init   = &raw_has_zero_init,
 572     .strong_runtime_opts  = raw_strong_runtime_opts,
 573 };
 574
 575 static void bdrv_raw_init(void)
 576 {
 577     bdrv_register(&bdrv_raw);
 578 }
 579
 580 block_init(bdrv_raw_init);