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