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/module.h"
  33 #include "qemu/option.h"
  34 #include "qemu/memalign.h"
  35
  36 typedef struct BDRVRawState {
  37     uint64_t offset;
  38     uint64_t size;
  39     bool has_size;
  40 } BDRVRawState;
  41
  42 static const char *const mutable_opts[] = { "offset", "size", NULL };
  43
  44 static QemuOptsList raw_runtime_opts = {
  45     .name = "raw",
  46     .head = QTAILQ_HEAD_INITIALIZER(raw_runtime_opts.head),
  47     .desc = {
  48         {
  49             .name = "offset",
  50             .type = QEMU_OPT_SIZE,
  51             .help = "offset in the disk where the image starts",
  52         },
  53         {
  54             .name = "size",
  55             .type = QEMU_OPT_SIZE,
  56             .help = "virtual disk size",
  57         },
  58         { /* end of list */ }
  59     },
  60 };
  61
  62 static QemuOptsList raw_create_opts = {
  63     .name = "raw-create-opts",
  64     .head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
  65     .desc = {
  66         {
  67             .name = BLOCK_OPT_SIZE,
  68             .type = QEMU_OPT_SIZE,
  69             .help = "Virtual disk size"
  70         },
  71         { /* end of list */ }
  72     }
  73 };
  74
  75 static int raw_read_options(QDict *options, uint64_t *offset, bool *has_size,
  76                             uint64_t *size, Error **errp)
  77 {
  78     QemuOpts *opts = NULL;
  79     int ret;
  80
  81     opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort);
  82     if (!qemu_opts_absorb_qdict(opts, options, errp)) {
  83         ret = -EINVAL;
  84         goto end;
  85     }
  86
  87     *offset = qemu_opt_get_size(opts, "offset", 0);
  88     *has_size = qemu_opt_find(opts, "size");
  89     *size = qemu_opt_get_size(opts, "size", 0);
  90
  91     ret = 0;
  92 end:
  93     qemu_opts_del(opts);
  94     return ret;
  95 }
  96
  97 static int raw_apply_options(BlockDriverState *bs, BDRVRawState *s,
  98                              uint64_t offset, bool has_size, uint64_t size,
  99                              Error **errp)
 100 {
 101     int64_t real_size = 0;
 102
 103     real_size = bdrv_getlength(bs->file->bs);
 104     if (real_size < 0) {
 105         error_setg_errno(errp, -real_size, "Could not get image size");
 106         return real_size;
 107     }
 108
 109     /* Check size and offset */
 110     if (offset > real_size) {
 111         error_setg(errp, "Offset (%" PRIu64 ") cannot be greater than "
 112                    "size of the containing file (%" PRId64 ")",
 113                    s->offset, real_size);
 114         return -EINVAL;
 115     }
 116
 117     if (has_size && (real_size - offset) < size) {
 118         error_setg(errp, "The sum of offset (%" PRIu64 ") and size "
 119                    "(%" PRIu64 ") has to be smaller or equal to the "
 120                    " actual size of the containing file (%" PRId64 ")",
 121                    s->offset, s->size, real_size);
 122         return -EINVAL;
 123     }
 124
 125     /* Make sure size is multiple of BDRV_SECTOR_SIZE to prevent rounding
 126      * up and leaking out of the specified area. */
 127     if (has_size && !QEMU_IS_ALIGNED(size, BDRV_SECTOR_SIZE)) {
 128         error_setg(errp, "Specified size is not multiple of %llu",
 129                    BDRV_SECTOR_SIZE);
 130         return -EINVAL;
 131     }
 132
 133     s->offset = offset;
 134     s->has_size = has_size;
 135     s->size = has_size ? size : real_size - offset;
 136
 137     return 0;
 138 }
 139
 140 static int raw_reopen_prepare(BDRVReopenState *reopen_state,
 141                               BlockReopenQueue *queue, Error **errp)
 142 {
 143     bool has_size;
 144     uint64_t offset, size;
 145     int ret;
 146
 147     assert(reopen_state != NULL);
 148     assert(reopen_state->bs != NULL);
 149
 150     reopen_state->opaque = g_new0(BDRVRawState, 1);
 151
 152     ret = raw_read_options(reopen_state->options, &offset, &has_size, &size,
 153                            errp);
 154     if (ret < 0) {
 155         return ret;
 156     }
 157
 158     ret = raw_apply_options(reopen_state->bs, reopen_state->opaque,
 159                             offset, has_size, size, errp);
 160     if (ret < 0) {
 161         return ret;
 162     }
 163
 164     return 0;
 165 }
 166
 167 static void raw_reopen_commit(BDRVReopenState *state)
 168 {
 169     BDRVRawState *new_s = state->opaque;
 170     BDRVRawState *s = state->bs->opaque;
 171
 172     memcpy(s, new_s, sizeof(BDRVRawState));
 173
 174     g_free(state->opaque);
 175     state->opaque = NULL;
 176 }
 177
 178 static void raw_reopen_abort(BDRVReopenState *state)
 179 {
 180     g_free(state->opaque);
 181     state->opaque = NULL;
 182 }
 183
 184 /* Check and adjust the offset, against 'offset' and 'size' options. */
 185 static inline int raw_adjust_offset(BlockDriverState *bs, int64_t *offset,
 186                                     int64_t bytes, bool is_write)
 187 {
 188     BDRVRawState *s = bs->opaque;
 189
 190     if (s->has_size && (*offset > s->size || bytes > (s->size - *offset))) {
 191         /* There's not enough space for the write, or the read request is
 192          * out-of-range. Don't read/write anything to prevent leaking out of
 193          * the size specified in options. */
 194         return is_write ? -ENOSPC : -EINVAL;
 195     }
 196
 197     if (*offset > INT64_MAX - s->offset) {
 198         return -EINVAL;
 199     }
 200     *offset += s->offset;
 201
 202     return 0;
 203 }
 204
 205 static int coroutine_fn raw_co_preadv(BlockDriverState *bs, int64_t offset,
 206                                       int64_t bytes, QEMUIOVector *qiov,
 207                                       BdrvRequestFlags flags)
 208 {
 209     int ret;
 210
 211     ret = raw_adjust_offset(bs, &offset, bytes, false);
 212     if (ret) {
 213         return ret;
 214     }
 215
 216     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 217     return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
 218 }
 219
 220 static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, int64_t offset,
 221                                        int64_t bytes, QEMUIOVector *qiov,
 222                                        BdrvRequestFlags flags)
 223 {
 224     void *buf = NULL;
 225     BlockDriver *drv;
 226     QEMUIOVector local_qiov;
 227     int ret;
 228
 229     if (bs->probed && offset < BLOCK_PROBE_BUF_SIZE && bytes) {
 230         /* Handling partial writes would be a pain - so we just
 231          * require that guests have 512-byte request alignment if
 232          * probing occurred */
 233         QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
 234         QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
 235         assert(offset == 0 && bytes >= BLOCK_PROBE_BUF_SIZE);
 236
 237         buf = qemu_try_blockalign(bs->file->bs, 512);
 238         if (!buf) {
 239             ret = -ENOMEM;
 240             goto fail;
 241         }
 242
 243         ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
 244         if (ret != 512) {
 245             ret = -EINVAL;
 246             goto fail;
 247         }
 248
 249         drv = bdrv_probe_all(buf, 512, NULL);
 250         if (drv != bs->drv) {
 251             ret = -EPERM;
 252             goto fail;
 253         }
 254
 255         /* Use the checked buffer, a malicious guest might be overwriting its
 256          * original buffer in the background. */
 257         qemu_iovec_init(&local_qiov, qiov->niov + 1);
 258         qemu_iovec_add(&local_qiov, buf, 512);
 259         qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
 260         qiov = &local_qiov;
 261     }
 262
 263     ret = raw_adjust_offset(bs, &offset, bytes, true);
 264     if (ret) {
 265         goto fail;
 266     }
 267
 268     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 269     ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
 270
 271 fail:
 272     if (qiov == &local_qiov) {
 273         qemu_iovec_destroy(&local_qiov);
 274     }
 275     qemu_vfree(buf);
 276     return ret;
 277 }
 278
 279 static int coroutine_fn raw_co_block_status(BlockDriverState *bs,
 280                                             bool want_zero, int64_t offset,
 281                                             int64_t bytes, int64_t *pnum,
 282                                             int64_t *map,
 283                                             BlockDriverState **file)
 284 {
 285     BDRVRawState *s = bs->opaque;
 286     *pnum = bytes;
 287     *file = bs->file->bs;
 288     *map = offset + s->offset;
 289     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID;
 290 }
 291
 292 static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
 293                                              int64_t offset, int64_t bytes,
 294                                              BdrvRequestFlags flags)
 295 {
 296     int ret;
 297
 298     ret = raw_adjust_offset(bs, &offset, bytes, true);
 299     if (ret) {
 300         return ret;
 301     }
 302     return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
 303 }
 304
 305 static int coroutine_fn raw_co_pdiscard(BlockDriverState *bs,
 306                                         int64_t offset, int64_t bytes)
 307 {
 308     int ret;
 309
 310     ret = raw_adjust_offset(bs, &offset, bytes, true);
 311     if (ret) {
 312         return ret;
 313     }
 314     return bdrv_co_pdiscard(bs->file, offset, bytes);
 315 }
 316
 317 static int64_t raw_getlength(BlockDriverState *bs)
 318 {
 319     int64_t len;
 320     BDRVRawState *s = bs->opaque;
 321
 322     /* Update size. It should not change unless the file was externally
 323      * modified. */
 324     len = bdrv_getlength(bs->file->bs);
 325     if (len < 0) {
 326         return len;
 327     }
 328
 329     if (len < s->offset) {
 330         s->size = 0;
 331     } else {
 332         if (s->has_size) {
 333             /* Try to honour the size */
 334             s->size = MIN(s->size, len - s->offset);
 335         } else {
 336             s->size = len - s->offset;
 337         }
 338     }
 339
 340     return s->size;
 341 }
 342
 343 static BlockMeasureInfo *raw_measure(QemuOpts *opts, BlockDriverState *in_bs,
 344                                      Error **errp)
 345 {
 346     BlockMeasureInfo *info;
 347     int64_t required;
 348
 349     if (in_bs) {
 350         required = bdrv_getlength(in_bs);
 351         if (required < 0) {
 352             error_setg_errno(errp, -required, "Unable to get image size");
 353             return NULL;
 354         }
 355     } else {
 356         required = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 357                             BDRV_SECTOR_SIZE);
 358     }
 359
 360     info = g_new0(BlockMeasureInfo, 1);
 361     info->required = required;
 362
 363     /* Unallocated sectors count towards the file size in raw images */
 364     info->fully_allocated = info->required;
 365     return info;
 366 }
 367
 368 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 369 {
 370     return bdrv_get_info(bs->file->bs, bdi);
 371 }
 372
 373 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 374 {
 375     if (bs->probed) {
 376         /* To make it easier to protect the first sector, any probed
 377          * image is restricted to read-modify-write on sub-sector
 378          * operations. */
 379         bs->bl.request_alignment = BDRV_SECTOR_SIZE;
 380     }
 381 }
 382
 383 static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
 384                                         bool exact, PreallocMode prealloc,
 385                                         BdrvRequestFlags flags, Error **errp)
 386 {
 387     BDRVRawState *s = bs->opaque;
 388
 389     if (s->has_size) {
 390         error_setg(errp, "Cannot resize fixed-size raw disks");
 391         return -ENOTSUP;
 392     }
 393
 394     if (INT64_MAX - offset < s->offset) {
 395         error_setg(errp, "Disk size too large for the chosen offset");
 396         return -EINVAL;
 397     }
 398
 399     s->size = offset;
 400     offset += s->offset;
 401     return bdrv_co_truncate(bs->file, offset, exact, prealloc, flags, errp);
 402 }
 403
 404 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 405 {
 406     bdrv_eject(bs->file->bs, eject_flag);
 407 }
 408
 409 static void raw_lock_medium(BlockDriverState *bs, bool locked)
 410 {
 411     bdrv_lock_medium(bs->file->bs, locked);
 412 }
 413
 414 static int raw_co_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
 415 {
 416     BDRVRawState *s = bs->opaque;
 417     if (s->offset || s->has_size) {
 418         return -ENOTSUP;
 419     }
 420     return bdrv_co_ioctl(bs->file->bs, req, buf);
 421 }
 422
 423 static int raw_has_zero_init(BlockDriverState *bs)
 424 {
 425     return bdrv_has_zero_init(bs->file->bs);
 426 }
 427
 428 static int coroutine_fn raw_co_create_opts(BlockDriver *drv,
 429                                            const char *filename,
 430                                            QemuOpts *opts,
 431                                            Error **errp)
 432 {
 433     return bdrv_create_file(filename, opts, errp);
 434 }
 435
 436 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 437                     Error **errp)
 438 {
 439     BDRVRawState *s = bs->opaque;
 440     bool has_size;
 441     uint64_t offset, size;
 442     BdrvChildRole file_role;
 443     int ret;
 444
 445     ret = raw_read_options(options, &offset, &has_size, &size, errp);
 446     if (ret < 0) {
 447         return ret;
 448     }
 449
 450     /*
 451      * Without offset and a size limit, this driver behaves very much
 452      * like a filter.  With any such limit, it does not.
 453      */
 454     if (offset || has_size) {
 455         file_role = BDRV_CHILD_DATA | BDRV_CHILD_PRIMARY;
 456     } else {
 457         file_role = BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY;
 458     }
 459
 460     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
 461                                file_role, false, errp);
 462     if (!bs->file) {
 463         return -EINVAL;
 464     }
 465
 466     bs->sg = bs->file->bs->sg;
 467     bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
 468         (BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
 469     bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
 470         ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
 471             bs->file->bs->supported_zero_flags);
 472     bs->supported_truncate_flags = bs->file->bs->supported_truncate_flags &
 473                                    BDRV_REQ_ZERO_WRITE;
 474
 475     if (bs->probed && !bdrv_is_read_only(bs)) {
 476         bdrv_refresh_filename(bs->file->bs);
 477         fprintf(stderr,
 478                 "WARNING: Image format was not specified for '%s' and probing "
 479                 "guessed raw.\n"
 480                 "         Automatically detecting the format is dangerous for "
 481                 "raw images, write operations on block 0 will be restricted.\n"
 482                 "         Specify the 'raw' format explicitly to remove the "
 483                 "restrictions.\n",
 484                 bs->file->bs->filename);
 485     }
 486
 487     ret = raw_apply_options(bs, s, offset, has_size, size, errp);
 488     if (ret < 0) {
 489         return ret;
 490     }
 491
 492     if (bs->sg && (s->offset || s->has_size)) {
 493         error_setg(errp, "Cannot use offset/size with SCSI generic devices");
 494         return -EINVAL;
 495     }
 496
 497     return 0;
 498 }
 499
 500 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 501 {
 502     /* smallest possible positive score so that raw is used if and only if no
 503      * other block driver works
 504      */
 505     return 1;
 506 }
 507
 508 static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
 509 {
 510     BDRVRawState *s = bs->opaque;
 511     int ret;
 512
 513     ret = bdrv_probe_blocksizes(bs->file->bs, bsz);
 514     if (ret < 0) {
 515         return ret;
 516     }
 517
 518     if (!QEMU_IS_ALIGNED(s->offset, MAX(bsz->log, bsz->phys))) {
 519         return -ENOTSUP;
 520     }
 521
 522     return 0;
 523 }
 524
 525 static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
 526 {
 527     BDRVRawState *s = bs->opaque;
 528     if (s->offset || s->has_size) {
 529         return -ENOTSUP;
 530     }
 531     return bdrv_probe_geometry(bs->file->bs, geo);
 532 }
 533
 534 static int coroutine_fn raw_co_copy_range_from(BlockDriverState *bs,
 535                                                BdrvChild *src,
 536                                                int64_t src_offset,
 537                                                BdrvChild *dst,
 538                                                int64_t dst_offset,
 539                                                int64_t bytes,
 540                                                BdrvRequestFlags read_flags,
 541                                                BdrvRequestFlags write_flags)
 542 {
 543     int ret;
 544
 545     ret = raw_adjust_offset(bs, &src_offset, bytes, false);
 546     if (ret) {
 547         return ret;
 548     }
 549     return bdrv_co_copy_range_from(bs->file, src_offset, dst, dst_offset,
 550                                    bytes, read_flags, write_flags);
 551 }
 552
 553 static int coroutine_fn raw_co_copy_range_to(BlockDriverState *bs,
 554                                              BdrvChild *src,
 555                                              int64_t src_offset,
 556                                              BdrvChild *dst,
 557                                              int64_t dst_offset,
 558                                              int64_t bytes,
 559                                              BdrvRequestFlags read_flags,
 560                                              BdrvRequestFlags write_flags)
 561 {
 562     int ret;
 563
 564     ret = raw_adjust_offset(bs, &dst_offset, bytes, true);
 565     if (ret) {
 566         return ret;
 567     }
 568     return bdrv_co_copy_range_to(src, src_offset, bs->file, dst_offset, bytes,
 569                                  read_flags, write_flags);
 570 }
 571
 572 static const char *const raw_strong_runtime_opts[] = {
 573     "offset",
 574     "size",
 575
 576     NULL
 577 };
 578
 579 static void raw_cancel_in_flight(BlockDriverState *bs)
 580 {
 581     bdrv_cancel_in_flight(bs->file->bs);
 582 }
 583
 584 static void raw_child_perm(BlockDriverState *bs, BdrvChild *c,
 585                            BdrvChildRole role,
 586                            BlockReopenQueue *reopen_queue,
 587                            uint64_t parent_perm, uint64_t parent_shared,
 588                            uint64_t *nperm, uint64_t *nshared)
 589 {
 590     bdrv_default_perms(bs, c, role, reopen_queue, parent_perm,
 591                        parent_shared, nperm, nshared);
 592
 593     /*
 594      * bdrv_default_perms() may add WRITE and/or RESIZE (see comment in
 595      * bdrv_default_perms_for_storage() for an explanation) but we only need
 596      * them if they are in parent_perm. Drop WRITE and RESIZE whenever possible
 597      * to avoid permission conflicts.
 598      */
 599     *nperm &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
 600     *nperm |= parent_perm & (BLK_PERM_WRITE | BLK_PERM_RESIZE);
 601 }
 602
 603 BlockDriver bdrv_raw = {
 604     .format_name          = "raw",
 605     .instance_size        = sizeof(BDRVRawState),
 606     .bdrv_probe           = &raw_probe,
 607     .bdrv_reopen_prepare  = &raw_reopen_prepare,
 608     .bdrv_reopen_commit   = &raw_reopen_commit,
 609     .bdrv_reopen_abort    = &raw_reopen_abort,
 610     .bdrv_open            = &raw_open,
 611     .bdrv_child_perm      = raw_child_perm,
 612     .bdrv_co_create_opts  = &raw_co_create_opts,
 613     .bdrv_co_preadv       = &raw_co_preadv,
 614     .bdrv_co_pwritev      = &raw_co_pwritev,
 615     .bdrv_co_pwrite_zeroes = &raw_co_pwrite_zeroes,
 616     .bdrv_co_pdiscard     = &raw_co_pdiscard,
 617     .bdrv_co_block_status = &raw_co_block_status,
 618     .bdrv_co_copy_range_from = &raw_co_copy_range_from,
 619     .bdrv_co_copy_range_to  = &raw_co_copy_range_to,
 620     .bdrv_co_truncate     = &raw_co_truncate,
 621     .bdrv_getlength       = &raw_getlength,
 622     .is_format            = true,
 623     .has_variable_length  = true,
 624     .bdrv_measure         = &raw_measure,
 625     .bdrv_get_info        = &raw_get_info,
 626     .bdrv_refresh_limits  = &raw_refresh_limits,
 627     .bdrv_probe_blocksizes = &raw_probe_blocksizes,
 628     .bdrv_probe_geometry  = &raw_probe_geometry,
 629     .bdrv_eject           = &raw_eject,
 630     .bdrv_lock_medium     = &raw_lock_medium,
 631     .bdrv_co_ioctl        = &raw_co_ioctl,
 632     .create_opts          = &raw_create_opts,
 633     .bdrv_has_zero_init   = &raw_has_zero_init,
 634     .strong_runtime_opts  = raw_strong_runtime_opts,
 635     .mutable_opts         = mutable_opts,
 636     .bdrv_cancel_in_flight = raw_cancel_in_flight,
 637 };
 638
 639 static void bdrv_raw_init(void)
 640 {
 641     bdrv_register(&bdrv_raw);
 642 }
 643
 644 block_init(bdrv_raw_init);