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 const char *const mutable_opts[] = { "offset", "size", NULL };
  41
  42 static QemuOptsList raw_runtime_opts = {
  43     .name = "raw",
  44     .head = QTAILQ_HEAD_INITIALIZER(raw_runtime_opts.head),
  45     .desc = {
  46         {
  47             .name = "offset",
  48             .type = QEMU_OPT_SIZE,
  49             .help = "offset in the disk where the image starts",
  50         },
  51         {
  52             .name = "size",
  53             .type = QEMU_OPT_SIZE,
  54             .help = "virtual disk size",
  55         },
  56         { /* end of list */ }
  57     },
  58 };
  59
  60 static QemuOptsList raw_create_opts = {
  61     .name = "raw-create-opts",
  62     .head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
  63     .desc = {
  64         {
  65             .name = BLOCK_OPT_SIZE,
  66             .type = QEMU_OPT_SIZE,
  67             .help = "Virtual disk size"
  68         },
  69         { /* end of list */ }
  70     }
  71 };
  72
  73 static int raw_read_options(QDict *options, BlockDriverState *bs,
  74     BDRVRawState *s, Error **errp)
  75 {
  76     Error *local_err = NULL;
  77     QemuOpts *opts = NULL;
  78     int64_t real_size = 0;
  79     int ret;
  80
  81     real_size = bdrv_getlength(bs->file->bs);
  82     if (real_size < 0) {
  83         error_setg_errno(errp, -real_size, "Could not get image size");
  84         return real_size;
  85     }
  86
  87     opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort);
  88     qemu_opts_absorb_qdict(opts, options, &local_err);
  89     if (local_err) {
  90         error_propagate(errp, local_err);
  91         ret = -EINVAL;
  92         goto end;
  93     }
  94
  95     s->offset = qemu_opt_get_size(opts, "offset", 0);
  96     if (s->offset > real_size) {
  97         error_setg(errp, "Offset (%" PRIu64 ") cannot be greater than "
  98             "size of the containing file (%" PRId64 ")",
  99             s->offset, real_size);
 100         ret = -EINVAL;
 101         goto end;
 102     }
 103
 104     if (qemu_opt_find(opts, "size") != NULL) {
 105         s->size = qemu_opt_get_size(opts, "size", 0);
 106         s->has_size = true;
 107     } else {
 108         s->has_size = false;
 109         s->size = real_size - s->offset;
 110     }
 111
 112     /* Check size and offset */
 113     if ((real_size - s->offset) < s->size) {
 114         error_setg(errp, "The sum of offset (%" PRIu64 ") and size "
 115             "(%" PRIu64 ") has to be smaller or equal to the "
 116             " actual size of the containing file (%" PRId64 ")",
 117             s->offset, s->size, real_size);
 118         ret = -EINVAL;
 119         goto end;
 120     }
 121
 122     /* Make sure size is multiple of BDRV_SECTOR_SIZE to prevent rounding
 123      * up and leaking out of the specified area. */
 124     if (s->has_size && !QEMU_IS_ALIGNED(s->size, BDRV_SECTOR_SIZE)) {
 125         error_setg(errp, "Specified size is not multiple of %llu",
 126             BDRV_SECTOR_SIZE);
 127         ret = -EINVAL;
 128         goto end;
 129     }
 130
 131     ret = 0;
 132
 133 end:
 134
 135     qemu_opts_del(opts);
 136
 137     return ret;
 138 }
 139
 140 static int raw_reopen_prepare(BDRVReopenState *reopen_state,
 141                               BlockReopenQueue *queue, Error **errp)
 142 {
 143     assert(reopen_state != NULL);
 144     assert(reopen_state->bs != NULL);
 145
 146     reopen_state->opaque = g_new0(BDRVRawState, 1);
 147
 148     return raw_read_options(
 149         reopen_state->options,
 150         reopen_state->bs,
 151         reopen_state->opaque,
 152         errp);
 153 }
 154
 155 static void raw_reopen_commit(BDRVReopenState *state)
 156 {
 157     BDRVRawState *new_s = state->opaque;
 158     BDRVRawState *s = state->bs->opaque;
 159
 160     memcpy(s, new_s, sizeof(BDRVRawState));
 161
 162     g_free(state->opaque);
 163     state->opaque = NULL;
 164 }
 165
 166 static void raw_reopen_abort(BDRVReopenState *state)
 167 {
 168     g_free(state->opaque);
 169     state->opaque = NULL;
 170 }
 171
 172 /* Check and adjust the offset, against 'offset' and 'size' options. */
 173 static inline int raw_adjust_offset(BlockDriverState *bs, uint64_t *offset,
 174                                     uint64_t bytes, bool is_write)
 175 {
 176     BDRVRawState *s = bs->opaque;
 177
 178     if (s->has_size && (*offset > s->size || bytes > (s->size - *offset))) {
 179         /* There's not enough space for the write, or the read request is
 180          * out-of-range. Don't read/write anything to prevent leaking out of
 181          * the size specified in options. */
 182         return is_write ? -ENOSPC : -EINVAL;
 183     }
 184
 185     if (*offset > INT64_MAX - s->offset) {
 186         return -EINVAL;
 187     }
 188     *offset += s->offset;
 189
 190     return 0;
 191 }
 192
 193 static int coroutine_fn raw_co_preadv(BlockDriverState *bs, uint64_t offset,
 194                                       uint64_t bytes, QEMUIOVector *qiov,
 195                                       int flags)
 196 {
 197     int ret;
 198
 199     ret = raw_adjust_offset(bs, &offset, bytes, false);
 200     if (ret) {
 201         return ret;
 202     }
 203
 204     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 205     return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
 206 }
 207
 208 static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
 209                                        uint64_t bytes, QEMUIOVector *qiov,
 210                                        int flags)
 211 {
 212     void *buf = NULL;
 213     BlockDriver *drv;
 214     QEMUIOVector local_qiov;
 215     int ret;
 216
 217     if (bs->probed && offset < BLOCK_PROBE_BUF_SIZE && bytes) {
 218         /* Handling partial writes would be a pain - so we just
 219          * require that guests have 512-byte request alignment if
 220          * probing occurred */
 221         QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
 222         QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
 223         assert(offset == 0 && bytes >= BLOCK_PROBE_BUF_SIZE);
 224
 225         buf = qemu_try_blockalign(bs->file->bs, 512);
 226         if (!buf) {
 227             ret = -ENOMEM;
 228             goto fail;
 229         }
 230
 231         ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
 232         if (ret != 512) {
 233             ret = -EINVAL;
 234             goto fail;
 235         }
 236
 237         drv = bdrv_probe_all(buf, 512, NULL);
 238         if (drv != bs->drv) {
 239             ret = -EPERM;
 240             goto fail;
 241         }
 242
 243         /* Use the checked buffer, a malicious guest might be overwriting its
 244          * original buffer in the background. */
 245         qemu_iovec_init(&local_qiov, qiov->niov + 1);
 246         qemu_iovec_add(&local_qiov, buf, 512);
 247         qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
 248         qiov = &local_qiov;
 249     }
 250
 251     ret = raw_adjust_offset(bs, &offset, bytes, true);
 252     if (ret) {
 253         goto fail;
 254     }
 255
 256     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 257     ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
 258
 259 fail:
 260     if (qiov == &local_qiov) {
 261         qemu_iovec_destroy(&local_qiov);
 262     }
 263     qemu_vfree(buf);
 264     return ret;
 265 }
 266
 267 static int coroutine_fn raw_co_block_status(BlockDriverState *bs,
 268                                             bool want_zero, int64_t offset,
 269                                             int64_t bytes, int64_t *pnum,
 270                                             int64_t *map,
 271                                             BlockDriverState **file)
 272 {
 273     BDRVRawState *s = bs->opaque;
 274     *pnum = bytes;
 275     *file = bs->file->bs;
 276     *map = offset + s->offset;
 277     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID;
 278 }
 279
 280 static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
 281                                              int64_t offset, int bytes,
 282                                              BdrvRequestFlags flags)
 283 {
 284     int ret;
 285
 286     ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
 287     if (ret) {
 288         return ret;
 289     }
 290     return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
 291 }
 292
 293 static int coroutine_fn raw_co_pdiscard(BlockDriverState *bs,
 294                                         int64_t offset, int bytes)
 295 {
 296     int ret;
 297
 298     ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
 299     if (ret) {
 300         return ret;
 301     }
 302     return bdrv_co_pdiscard(bs->file, offset, bytes);
 303 }
 304
 305 static int64_t raw_getlength(BlockDriverState *bs)
 306 {
 307     int64_t len;
 308     BDRVRawState *s = bs->opaque;
 309
 310     /* Update size. It should not change unless the file was externally
 311      * modified. */
 312     len = bdrv_getlength(bs->file->bs);
 313     if (len < 0) {
 314         return len;
 315     }
 316
 317     if (len < s->offset) {
 318         s->size = 0;
 319     } else {
 320         if (s->has_size) {
 321             /* Try to honour the size */
 322             s->size = MIN(s->size, len - s->offset);
 323         } else {
 324             s->size = len - s->offset;
 325         }
 326     }
 327
 328     return s->size;
 329 }
 330
 331 static BlockMeasureInfo *raw_measure(QemuOpts *opts, BlockDriverState *in_bs,
 332                                      Error **errp)
 333 {
 334     BlockMeasureInfo *info;
 335     int64_t required;
 336
 337     if (in_bs) {
 338         required = bdrv_getlength(in_bs);
 339         if (required < 0) {
 340             error_setg_errno(errp, -required, "Unable to get image size");
 341             return NULL;
 342         }
 343     } else {
 344         required = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 345                             BDRV_SECTOR_SIZE);
 346     }
 347
 348     info = g_new(BlockMeasureInfo, 1);
 349     info->required = required;
 350
 351     /* Unallocated sectors count towards the file size in raw images */
 352     info->fully_allocated = info->required;
 353     return info;
 354 }
 355
 356 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 357 {
 358     return bdrv_get_info(bs->file->bs, bdi);
 359 }
 360
 361 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 362 {
 363     if (bs->probed) {
 364         /* To make it easier to protect the first sector, any probed
 365          * image is restricted to read-modify-write on sub-sector
 366          * operations. */
 367         bs->bl.request_alignment = BDRV_SECTOR_SIZE;
 368     }
 369 }
 370
 371 static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
 372                                         PreallocMode prealloc, Error **errp)
 373 {
 374     BDRVRawState *s = bs->opaque;
 375
 376     if (s->has_size) {
 377         error_setg(errp, "Cannot resize fixed-size raw disks");
 378         return -ENOTSUP;
 379     }
 380
 381     if (INT64_MAX - offset < s->offset) {
 382         error_setg(errp, "Disk size too large for the chosen offset");
 383         return -EINVAL;
 384     }
 385
 386     s->size = offset;
 387     offset += s->offset;
 388     return bdrv_co_truncate(bs->file, offset, prealloc, errp);
 389 }
 390
 391 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 392 {
 393     bdrv_eject(bs->file->bs, eject_flag);
 394 }
 395
 396 static void raw_lock_medium(BlockDriverState *bs, bool locked)
 397 {
 398     bdrv_lock_medium(bs->file->bs, locked);
 399 }
 400
 401 static int raw_co_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
 402 {
 403     BDRVRawState *s = bs->opaque;
 404     if (s->offset || s->has_size) {
 405         return -ENOTSUP;
 406     }
 407     return bdrv_co_ioctl(bs->file->bs, req, buf);
 408 }
 409
 410 static int raw_has_zero_init(BlockDriverState *bs)
 411 {
 412     return bdrv_has_zero_init(bs->file->bs);
 413 }
 414
 415 static int coroutine_fn raw_co_create_opts(const char *filename, QemuOpts *opts,
 416                                            Error **errp)
 417 {
 418     return bdrv_create_file(filename, opts, errp);
 419 }
 420
 421 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 422                     Error **errp)
 423 {
 424     BDRVRawState *s = bs->opaque;
 425     int ret;
 426
 427     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
 428                                false, errp);
 429     if (!bs->file) {
 430         return -EINVAL;
 431     }
 432
 433     bs->sg = bs->file->bs->sg;
 434     bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
 435         (BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
 436     bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
 437         ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
 438             bs->file->bs->supported_zero_flags);
 439
 440     if (bs->probed && !bdrv_is_read_only(bs)) {
 441         bdrv_refresh_filename(bs->file->bs);
 442         fprintf(stderr,
 443                 "WARNING: Image format was not specified for '%s' and probing "
 444                 "guessed raw.\n"
 445                 "         Automatically detecting the format is dangerous for "
 446                 "raw images, write operations on block 0 will be restricted.\n"
 447                 "         Specify the 'raw' format explicitly to remove the "
 448                 "restrictions.\n",
 449                 bs->file->bs->filename);
 450     }
 451
 452     ret = raw_read_options(options, bs, s, errp);
 453     if (ret < 0) {
 454         return ret;
 455     }
 456
 457     if (bs->sg && (s->offset || s->has_size)) {
 458         error_setg(errp, "Cannot use offset/size with SCSI generic devices");
 459         return -EINVAL;
 460     }
 461
 462     return 0;
 463 }
 464
 465 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 466 {
 467     /* smallest possible positive score so that raw is used if and only if no
 468      * other block driver works
 469      */
 470     return 1;
 471 }
 472
 473 static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
 474 {
 475     BDRVRawState *s = bs->opaque;
 476     int ret;
 477
 478     ret = bdrv_probe_blocksizes(bs->file->bs, bsz);
 479     if (ret < 0) {
 480         return ret;
 481     }
 482
 483     if (!QEMU_IS_ALIGNED(s->offset, MAX(bsz->log, bsz->phys))) {
 484         return -ENOTSUP;
 485     }
 486
 487     return 0;
 488 }
 489
 490 static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
 491 {
 492     BDRVRawState *s = bs->opaque;
 493     if (s->offset || s->has_size) {
 494         return -ENOTSUP;
 495     }
 496     return bdrv_probe_geometry(bs->file->bs, geo);
 497 }
 498
 499 static int coroutine_fn raw_co_copy_range_from(BlockDriverState *bs,
 500                                                BdrvChild *src,
 501                                                uint64_t src_offset,
 502                                                BdrvChild *dst,
 503                                                uint64_t dst_offset,
 504                                                uint64_t bytes,
 505                                                BdrvRequestFlags read_flags,
 506                                                BdrvRequestFlags write_flags)
 507 {
 508     int ret;
 509
 510     ret = raw_adjust_offset(bs, &src_offset, bytes, false);
 511     if (ret) {
 512         return ret;
 513     }
 514     return bdrv_co_copy_range_from(bs->file, src_offset, dst, dst_offset,
 515                                    bytes, read_flags, write_flags);
 516 }
 517
 518 static int coroutine_fn raw_co_copy_range_to(BlockDriverState *bs,
 519                                              BdrvChild *src,
 520                                              uint64_t src_offset,
 521                                              BdrvChild *dst,
 522                                              uint64_t dst_offset,
 523                                              uint64_t bytes,
 524                                              BdrvRequestFlags read_flags,
 525                                              BdrvRequestFlags write_flags)
 526 {
 527     int ret;
 528
 529     ret = raw_adjust_offset(bs, &dst_offset, bytes, true);
 530     if (ret) {
 531         return ret;
 532     }
 533     return bdrv_co_copy_range_to(src, src_offset, bs->file, dst_offset, bytes,
 534                                  read_flags, write_flags);
 535 }
 536
 537 static const char *const raw_strong_runtime_opts[] = {
 538     "offset",
 539     "size",
 540
 541     NULL
 542 };
 543
 544 BlockDriver bdrv_raw = {
 545     .format_name          = "raw",
 546     .instance_size        = sizeof(BDRVRawState),
 547     .bdrv_probe           = &raw_probe,
 548     .bdrv_reopen_prepare  = &raw_reopen_prepare,
 549     .bdrv_reopen_commit   = &raw_reopen_commit,
 550     .bdrv_reopen_abort    = &raw_reopen_abort,
 551     .bdrv_open            = &raw_open,
 552     .bdrv_child_perm      = bdrv_filter_default_perms,
 553     .bdrv_co_create_opts  = &raw_co_create_opts,
 554     .bdrv_co_preadv       = &raw_co_preadv,
 555     .bdrv_co_pwritev      = &raw_co_pwritev,
 556     .bdrv_co_pwrite_zeroes = &raw_co_pwrite_zeroes,
 557     .bdrv_co_pdiscard     = &raw_co_pdiscard,
 558     .bdrv_co_block_status = &raw_co_block_status,
 559     .bdrv_co_copy_range_from = &raw_co_copy_range_from,
 560     .bdrv_co_copy_range_to  = &raw_co_copy_range_to,
 561     .bdrv_co_truncate     = &raw_co_truncate,
 562     .bdrv_getlength       = &raw_getlength,
 563     .has_variable_length  = true,
 564     .bdrv_measure         = &raw_measure,
 565     .bdrv_get_info        = &raw_get_info,
 566     .bdrv_refresh_limits  = &raw_refresh_limits,
 567     .bdrv_probe_blocksizes = &raw_probe_blocksizes,
 568     .bdrv_probe_geometry  = &raw_probe_geometry,
 569     .bdrv_eject           = &raw_eject,
 570     .bdrv_lock_medium     = &raw_lock_medium,
 571     .bdrv_co_ioctl        = &raw_co_ioctl,
 572     .create_opts          = &raw_create_opts,
 573     .bdrv_has_zero_init   = &raw_has_zero_init,
 574     .strong_runtime_opts  = raw_strong_runtime_opts,
 575     .mutable_opts         = mutable_opts,
 576 };
 577
 578 static void bdrv_raw_init(void)
 579 {
 580     bdrv_register(&bdrv_raw);
 581 }
 582
 583 block_init(bdrv_raw_init);