block/dmg.c

   1 /*
   2  * QEMU Block driver for DMG images
   3  *
   4  * Copyright (c) 2004 Johannes E. Schindelin
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu/osdep.h"
  25 #include "qapi/error.h"
  26 #include "block/block-io.h"
  27 #include "block/block_int.h"
  28 #include "qemu/bswap.h"
  29 #include "qemu/error-report.h"
  30 #include "qemu/module.h"
  31 #include "qemu/memalign.h"
  32 #include "dmg.h"
  33
  34 BdrvDmgUncompressFunc *dmg_uncompress_bz2;
  35 BdrvDmgUncompressFunc *dmg_uncompress_lzfse;
  36
  37 enum {
  38     /* Limit chunk sizes to prevent unreasonable amounts of memory being used
  39      * or truncating when converting to 32-bit types
  40      */
  41     DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */
  42     DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512,
  43 };
  44
  45 enum {
  46     /* DMG Block Type */
  47     UDZE = 0, /* Zeroes */
  48     UDRW,     /* RAW type */
  49     UDIG,     /* Ignore */
  50     UDCO = 0x80000004,
  51     UDZO,
  52     UDBZ,
  53     ULFO,
  54     UDCM = 0x7ffffffe, /* Comments */
  55     UDLE = 0xffffffff  /* Last Entry */
  56 };
  57
  58 static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
  59 {
  60     int len;
  61
  62     if (!filename) {
  63         return 0;
  64     }
  65
  66     len = strlen(filename);
  67     if (len > 4 && !strcmp(filename + len - 4, ".dmg")) {
  68         return 2;
  69     }
  70     return 0;
  71 }
  72
  73 static int GRAPH_RDLOCK
  74 read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result)
  75 {
  76     uint64_t buffer;
  77     int ret;
  78
  79     ret = bdrv_pread(bs->file, offset, 8, &buffer, 0);
  80     if (ret < 0) {
  81         return ret;
  82     }
  83
  84     *result = be64_to_cpu(buffer);
  85     return 0;
  86 }
  87
  88 static int GRAPH_RDLOCK
  89 read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result)
  90 {
  91     uint32_t buffer;
  92     int ret;
  93
  94     ret = bdrv_pread(bs->file, offset, 4, &buffer, 0);
  95     if (ret < 0) {
  96         return ret;
  97     }
  98
  99     *result = be32_to_cpu(buffer);
 100     return 0;
 101 }
 102
 103 static inline uint64_t buff_read_uint64(const uint8_t *buffer, int64_t offset)
 104 {
 105     return be64_to_cpu(*(uint64_t *)&buffer[offset]);
 106 }
 107
 108 static inline uint32_t buff_read_uint32(const uint8_t *buffer, int64_t offset)
 109 {
 110     return be32_to_cpu(*(uint32_t *)&buffer[offset]);
 111 }
 112
 113 /* Increase max chunk sizes, if necessary.  This function is used to calculate
 114  * the buffer sizes needed for compressed/uncompressed chunk I/O.
 115  */
 116 static void update_max_chunk_size(BDRVDMGState *s, uint32_t chunk,
 117                                   uint32_t *max_compressed_size,
 118                                   uint32_t *max_sectors_per_chunk)
 119 {
 120     uint32_t compressed_size = 0;
 121     uint32_t uncompressed_sectors = 0;
 122
 123     switch (s->types[chunk]) {
 124     case UDZO: /* zlib compressed */
 125     case UDBZ: /* bzip2 compressed */
 126     case ULFO: /* lzfse compressed */
 127         compressed_size = s->lengths[chunk];
 128         uncompressed_sectors = s->sectorcounts[chunk];
 129         break;
 130     case UDRW: /* copy */
 131         uncompressed_sectors = DIV_ROUND_UP(s->lengths[chunk], 512);
 132         break;
 133     case UDZE: /* zero */
 134     case UDIG: /* ignore */
 135         /* as the all-zeroes block may be large, it is treated specially: the
 136          * sector is not copied from a large buffer, a simple memset is used
 137          * instead. Therefore uncompressed_sectors does not need to be set. */
 138         break;
 139     }
 140
 141     if (compressed_size > *max_compressed_size) {
 142         *max_compressed_size = compressed_size;
 143     }
 144     if (uncompressed_sectors > *max_sectors_per_chunk) {
 145         *max_sectors_per_chunk = uncompressed_sectors;
 146     }
 147 }
 148
 149 static int64_t dmg_find_koly_offset(BdrvChild *file, Error **errp)
 150 {
 151     BlockDriverState *file_bs = file->bs;
 152     int64_t length;
 153     int64_t offset = 0;
 154     uint8_t buffer[515];
 155     int i, ret;
 156
 157     /* bdrv_getlength returns a multiple of block size (512), rounded up. Since
 158      * dmg images can have odd sizes, try to look for the "koly" magic which
 159      * marks the begin of the UDIF trailer (512 bytes). This magic can be found
 160      * in the last 511 bytes of the second-last sector or the first 4 bytes of
 161      * the last sector (search space: 515 bytes) */
 162     length = bdrv_getlength(file_bs);
 163     if (length < 0) {
 164         error_setg_errno(errp, -length,
 165             "Failed to get file size while reading UDIF trailer");
 166         return length;
 167     } else if (length < 512) {
 168         error_setg(errp, "dmg file must be at least 512 bytes long");
 169         return -EINVAL;
 170     }
 171     if (length > 511 + 512) {
 172         offset = length - 511 - 512;
 173     }
 174     length = length < 515 ? length : 515;
 175     ret = bdrv_pread(file, offset, length, buffer, 0);
 176     if (ret < 0) {
 177         error_setg_errno(errp, -ret, "Failed while reading UDIF trailer");
 178         return ret;
 179     }
 180     for (i = 0; i < length - 3; i++) {
 181         if (buffer[i] == 'k' && buffer[i+1] == 'o' &&
 182             buffer[i+2] == 'l' && buffer[i+3] == 'y') {
 183             return offset + i;
 184         }
 185     }
 186     error_setg(errp, "Could not locate UDIF trailer in dmg file");
 187     return -EINVAL;
 188 }
 189
 190 /* used when building the sector table */
 191 typedef struct DmgHeaderState {
 192     /* used internally by dmg_read_mish_block to remember offsets of blocks
 193      * across calls */
 194     uint64_t data_fork_offset;
 195     /* exported for dmg_open */
 196     uint32_t max_compressed_size;
 197     uint32_t max_sectors_per_chunk;
 198 } DmgHeaderState;
 199
 200 static bool dmg_is_known_block_type(uint32_t entry_type)
 201 {
 202     switch (entry_type) {
 203     case UDZE:    /* zeros */
 204     case UDRW:    /* uncompressed */
 205     case UDIG:    /* ignore */
 206     case UDZO:    /* zlib */
 207         return true;
 208     case UDBZ:    /* bzip2 */
 209         return !!dmg_uncompress_bz2;
 210     case ULFO:    /* lzfse */
 211         return !!dmg_uncompress_lzfse;
 212     default:
 213         return false;
 214     }
 215 }
 216
 217 static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds,
 218                                uint8_t *buffer, uint32_t count)
 219 {
 220     uint32_t type, i;
 221     int ret;
 222     size_t new_size;
 223     uint32_t chunk_count;
 224     int64_t offset = 0;
 225     uint64_t data_offset;
 226     uint64_t in_offset = ds->data_fork_offset;
 227     uint64_t out_offset;
 228
 229     type = buff_read_uint32(buffer, offset);
 230     /* skip data that is not a valid MISH block (invalid magic or too small) */
 231     if (type != 0x6d697368 || count < 244) {
 232         /* assume success for now */
 233         return 0;
 234     }
 235
 236     /* chunk offsets are relative to this sector number */
 237     out_offset = buff_read_uint64(buffer, offset + 8);
 238
 239     /* location in data fork for (compressed) blob (in bytes) */
 240     data_offset = buff_read_uint64(buffer, offset + 0x18);
 241     in_offset += data_offset;
 242
 243     /* move to begin of chunk entries */
 244     offset += 204;
 245
 246     chunk_count = (count - 204) / 40;
 247     new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
 248     s->types = g_realloc(s->types, new_size / 2);
 249     s->offsets = g_realloc(s->offsets, new_size);
 250     s->lengths = g_realloc(s->lengths, new_size);
 251     s->sectors = g_realloc(s->sectors, new_size);
 252     s->sectorcounts = g_realloc(s->sectorcounts, new_size);
 253
 254     for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) {
 255         s->types[i] = buff_read_uint32(buffer, offset);
 256         if (!dmg_is_known_block_type(s->types[i])) {
 257             switch (s->types[i]) {
 258             case UDBZ:
 259                 warn_report_once("dmg-bzip2 module is missing, accessing bzip2 "
 260                                  "compressed blocks will result in I/O errors");
 261                 break;
 262             case ULFO:
 263                 warn_report_once("dmg-lzfse module is missing, accessing lzfse "
 264                                  "compressed blocks will result in I/O errors");
 265                 break;
 266             case UDCM:
 267             case UDLE:
 268                 /* Comments and last entry can be ignored without problems */
 269                 break;
 270             default:
 271                 warn_report_once("Image contains chunks of unknown type %x, "
 272                                  "accessing them will result in I/O errors",
 273                                  s->types[i]);
 274                 break;
 275             }
 276             chunk_count--;
 277             i--;
 278             offset += 40;
 279             continue;
 280         }
 281
 282         /* sector number */
 283         s->sectors[i] = buff_read_uint64(buffer, offset + 8);
 284         s->sectors[i] += out_offset;
 285
 286         /* sector count */
 287         s->sectorcounts[i] = buff_read_uint64(buffer, offset + 0x10);
 288
 289         /* all-zeroes sector (type UDZE and UDIG) does not need to be
 290          * "uncompressed" and can therefore be unbounded. */
 291         if (s->types[i] != UDZE && s->types[i] != UDIG
 292             && s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) {
 293             error_report("sector count %" PRIu64 " for chunk %" PRIu32
 294                          " is larger than max (%u)",
 295                          s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX);
 296             ret = -EINVAL;
 297             goto fail;
 298         }
 299
 300         /* offset in (compressed) data fork */
 301         s->offsets[i] = buff_read_uint64(buffer, offset + 0x18);
 302         s->offsets[i] += in_offset;
 303
 304         /* length in (compressed) data fork */
 305         s->lengths[i] = buff_read_uint64(buffer, offset + 0x20);
 306
 307         if (s->lengths[i] > DMG_LENGTHS_MAX) {
 308             error_report("length %" PRIu64 " for chunk %" PRIu32
 309                          " is larger than max (%u)",
 310                          s->lengths[i], i, DMG_LENGTHS_MAX);
 311             ret = -EINVAL;
 312             goto fail;
 313         }
 314
 315         update_max_chunk_size(s, i, &ds->max_compressed_size,
 316                               &ds->max_sectors_per_chunk);
 317         offset += 40;
 318     }
 319     s->n_chunks += chunk_count;
 320     return 0;
 321
 322 fail:
 323     return ret;
 324 }
 325
 326 static int GRAPH_RDLOCK
 327 dmg_read_resource_fork(BlockDriverState *bs, DmgHeaderState *ds,
 328                        uint64_t info_begin, uint64_t info_length)
 329 {
 330     BDRVDMGState *s = bs->opaque;
 331     int ret;
 332     uint32_t count, rsrc_data_offset;
 333     uint8_t *buffer = NULL;
 334     uint64_t info_end;
 335     uint64_t offset;
 336
 337     /* read offset from begin of resource fork (info_begin) to resource data */
 338     ret = read_uint32(bs, info_begin, &rsrc_data_offset);
 339     if (ret < 0) {
 340         goto fail;
 341     } else if (rsrc_data_offset > info_length) {
 342         ret = -EINVAL;
 343         goto fail;
 344     }
 345
 346     /* read length of resource data */
 347     ret = read_uint32(bs, info_begin + 8, &count);
 348     if (ret < 0) {
 349         goto fail;
 350     } else if (count == 0 || rsrc_data_offset + count > info_length) {
 351         ret = -EINVAL;
 352         goto fail;
 353     }
 354
 355     /* begin of resource data (consisting of one or more resources) */
 356     offset = info_begin + rsrc_data_offset;
 357
 358     /* end of resource data (there is possibly a following resource map
 359      * which will be ignored). */
 360     info_end = offset + count;
 361
 362     /* read offsets (mish blocks) from one or more resources in resource data */
 363     while (offset < info_end) {
 364         /* size of following resource */
 365         ret = read_uint32(bs, offset, &count);
 366         if (ret < 0) {
 367             goto fail;
 368         } else if (count == 0 || count > info_end - offset) {
 369             ret = -EINVAL;
 370             goto fail;
 371         }
 372         offset += 4;
 373
 374         buffer = g_realloc(buffer, count);
 375         ret = bdrv_pread(bs->file, offset, count, buffer, 0);
 376         if (ret < 0) {
 377             goto fail;
 378         }
 379
 380         ret = dmg_read_mish_block(s, ds, buffer, count);
 381         if (ret < 0) {
 382             goto fail;
 383         }
 384         /* advance offset by size of resource */
 385         offset += count;
 386     }
 387     ret = 0;
 388
 389 fail:
 390     g_free(buffer);
 391     return ret;
 392 }
 393
 394 static int GRAPH_RDLOCK
 395 dmg_read_plist_xml(BlockDriverState *bs, DmgHeaderState *ds,
 396                    uint64_t info_begin, uint64_t info_length)
 397 {
 398     BDRVDMGState *s = bs->opaque;
 399     int ret;
 400     uint8_t *buffer = NULL;
 401     char *data_begin, *data_end;
 402
 403     /* Have at least some length to avoid NULL for g_malloc. Attempt to set a
 404      * safe upper cap on the data length. A test sample had a XML length of
 405      * about 1 MiB. */
 406     if (info_length == 0 || info_length > 16 * 1024 * 1024) {
 407         ret = -EINVAL;
 408         goto fail;
 409     }
 410
 411     buffer = g_malloc(info_length + 1);
 412     buffer[info_length] = '\0';
 413     ret = bdrv_pread(bs->file, info_begin, info_length, buffer, 0);
 414     if (ret < 0) {
 415         ret = -EINVAL;
 416         goto fail;
 417     }
 418
 419     /* look for <data>...</data>. The data is 284 (0x11c) bytes after base64
 420      * decode. The actual data element has 431 (0x1af) bytes which includes tabs
 421      * and line feeds. */
 422     data_end = (char *)buffer;
 423     while ((data_begin = strstr(data_end, "<data>")) != NULL) {
 424         guchar *mish;
 425         gsize out_len = 0;
 426
 427         data_begin += 6;
 428         data_end = strstr(data_begin, "</data>");
 429         /* malformed XML? */
 430         if (data_end == NULL) {
 431             ret = -EINVAL;
 432             goto fail;
 433         }
 434         *data_end++ = '\0';
 435         mish = g_base64_decode(data_begin, &out_len);
 436         ret = dmg_read_mish_block(s, ds, mish, (uint32_t)out_len);
 437         g_free(mish);
 438         if (ret < 0) {
 439             goto fail;
 440         }
 441     }
 442     ret = 0;
 443
 444 fail:
 445     g_free(buffer);
 446     return ret;
 447 }
 448
 449 static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
 450                     Error **errp)
 451 {
 452     BDRVDMGState *s = bs->opaque;
 453     DmgHeaderState ds;
 454     uint64_t rsrc_fork_offset, rsrc_fork_length;
 455     uint64_t plist_xml_offset, plist_xml_length;
 456     int64_t offset;
 457     int ret;
 458
 459     GLOBAL_STATE_CODE();
 460
 461     bdrv_graph_rdlock_main_loop();
 462     ret = bdrv_apply_auto_read_only(bs, NULL, errp);
 463     bdrv_graph_rdunlock_main_loop();
 464     if (ret < 0) {
 465         return ret;
 466     }
 467
 468     ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
 469     if (ret < 0) {
 470         return ret;
 471     }
 472
 473     GRAPH_RDLOCK_GUARD_MAINLOOP();
 474
 475     /*
 476      * NB: if uncompress submodules are absent,
 477      * ie block_module_load return value == 0, the function pointers
 478      * dmg_uncompress_bz2 and dmg_uncompress_lzfse will be NULL.
 479      */
 480     if (block_module_load("dmg-bz2", errp) < 0) {
 481         return -EINVAL;
 482     }
 483     if (block_module_load("dmg-lzfse", errp) < 0) {
 484         return -EINVAL;
 485     }
 486
 487     s->n_chunks = 0;
 488     s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
 489     /* used by dmg_read_mish_block to keep track of the current I/O position */
 490     ds.data_fork_offset = 0;
 491     ds.max_compressed_size = 1;
 492     ds.max_sectors_per_chunk = 1;
 493
 494     /* locate the UDIF trailer */
 495     offset = dmg_find_koly_offset(bs->file, errp);
 496     if (offset < 0) {
 497         ret = offset;
 498         goto fail;
 499     }
 500
 501     /* offset of data fork (DataForkOffset) */
 502     ret = read_uint64(bs, offset + 0x18, &ds.data_fork_offset);
 503     if (ret < 0) {
 504         goto fail;
 505     } else if (ds.data_fork_offset > offset) {
 506         ret = -EINVAL;
 507         goto fail;
 508     }
 509
 510     /* offset of resource fork (RsrcForkOffset) */
 511     ret = read_uint64(bs, offset + 0x28, &rsrc_fork_offset);
 512     if (ret < 0) {
 513         goto fail;
 514     }
 515     ret = read_uint64(bs, offset + 0x30, &rsrc_fork_length);
 516     if (ret < 0) {
 517         goto fail;
 518     }
 519     if (rsrc_fork_offset >= offset ||
 520         rsrc_fork_length > offset - rsrc_fork_offset) {
 521         ret = -EINVAL;
 522         goto fail;
 523     }
 524     /* offset of property list (XMLOffset) */
 525     ret = read_uint64(bs, offset + 0xd8, &plist_xml_offset);
 526     if (ret < 0) {
 527         goto fail;
 528     }
 529     ret = read_uint64(bs, offset + 0xe0, &plist_xml_length);
 530     if (ret < 0) {
 531         goto fail;
 532     }
 533     if (plist_xml_offset >= offset ||
 534         plist_xml_length > offset - plist_xml_offset) {
 535         ret = -EINVAL;
 536         goto fail;
 537     }
 538     ret = read_uint64(bs, offset + 0x1ec, (uint64_t *)&bs->total_sectors);
 539     if (ret < 0) {
 540         goto fail;
 541     }
 542     if (bs->total_sectors < 0) {
 543         ret = -EINVAL;
 544         goto fail;
 545     }
 546     if (rsrc_fork_length != 0) {
 547         ret = dmg_read_resource_fork(bs, &ds,
 548                                      rsrc_fork_offset, rsrc_fork_length);
 549         if (ret < 0) {
 550             goto fail;
 551         }
 552     } else if (plist_xml_length != 0) {
 553         ret = dmg_read_plist_xml(bs, &ds, plist_xml_offset, plist_xml_length);
 554         if (ret < 0) {
 555             goto fail;
 556         }
 557     } else {
 558         ret = -EINVAL;
 559         goto fail;
 560     }
 561
 562     /* initialize zlib engine */
 563     s->compressed_chunk = qemu_try_blockalign(bs->file->bs,
 564                                               ds.max_compressed_size + 1);
 565     s->uncompressed_chunk = qemu_try_blockalign(bs->file->bs,
 566                                                 512 * ds.max_sectors_per_chunk);
 567     if (s->compressed_chunk == NULL || s->uncompressed_chunk == NULL) {
 568         ret = -ENOMEM;
 569         goto fail;
 570     }
 571
 572     if (inflateInit(&s->zstream) != Z_OK) {
 573         ret = -EINVAL;
 574         goto fail;
 575     }
 576
 577     s->current_chunk = s->n_chunks;
 578
 579     qemu_co_mutex_init(&s->lock);
 580     return 0;
 581
 582 fail:
 583     g_free(s->types);
 584     g_free(s->offsets);
 585     g_free(s->lengths);
 586     g_free(s->sectors);
 587     g_free(s->sectorcounts);
 588     qemu_vfree(s->compressed_chunk);
 589     qemu_vfree(s->uncompressed_chunk);
 590     return ret;
 591 }
 592
 593 static void dmg_refresh_limits(BlockDriverState *bs, Error **errp)
 594 {
 595     bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
 596 }
 597
 598 static inline int is_sector_in_chunk(BDRVDMGState *s,
 599                 uint32_t chunk_num, uint64_t sector_num)
 600 {
 601     if (chunk_num >= s->n_chunks || s->sectors[chunk_num] > sector_num ||
 602             s->sectors[chunk_num] + s->sectorcounts[chunk_num] <= sector_num) {
 603         return 0;
 604     } else {
 605         return -1;
 606     }
 607 }
 608
 609 static inline uint32_t search_chunk(BDRVDMGState *s, uint64_t sector_num)
 610 {
 611     /* binary search */
 612     uint32_t chunk1 = 0, chunk2 = s->n_chunks, chunk3;
 613     while (chunk1 <= chunk2) {
 614         chunk3 = (chunk1 + chunk2) / 2;
 615         if (s->sectors[chunk3] > sector_num) {
 616             if (chunk3 == 0) {
 617                 goto err;
 618             }
 619             chunk2 = chunk3 - 1;
 620         } else if (s->sectors[chunk3] + s->sectorcounts[chunk3] > sector_num) {
 621             return chunk3;
 622         } else {
 623             chunk1 = chunk3 + 1;
 624         }
 625     }
 626 err:
 627     return s->n_chunks; /* error */
 628 }
 629
 630 static int coroutine_fn GRAPH_RDLOCK
 631 dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num)
 632 {
 633     BDRVDMGState *s = bs->opaque;
 634
 635     if (!is_sector_in_chunk(s, s->current_chunk, sector_num)) {
 636         int ret;
 637         uint32_t chunk = search_chunk(s, sector_num);
 638
 639         if (chunk >= s->n_chunks) {
 640             return -1;
 641         }
 642
 643         s->current_chunk = s->n_chunks;
 644         switch (s->types[chunk]) { /* block entry type */
 645         case UDZO: { /* zlib compressed */
 646             /* we need to buffer, because only the chunk as whole can be
 647              * inflated. */
 648             ret = bdrv_co_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
 649                                 s->compressed_chunk, 0);
 650             if (ret < 0) {
 651                 return -1;
 652             }
 653
 654             s->zstream.next_in = s->compressed_chunk;
 655             s->zstream.avail_in = s->lengths[chunk];
 656             s->zstream.next_out = s->uncompressed_chunk;
 657             s->zstream.avail_out = 512 * s->sectorcounts[chunk];
 658             ret = inflateReset(&s->zstream);
 659             if (ret != Z_OK) {
 660                 return -1;
 661             }
 662             ret = inflate(&s->zstream, Z_FINISH);
 663             if (ret != Z_STREAM_END ||
 664                 s->zstream.total_out != 512 * s->sectorcounts[chunk]) {
 665                 return -1;
 666             }
 667             break; }
 668         case UDBZ: /* bzip2 compressed */
 669             if (!dmg_uncompress_bz2) {
 670                 break;
 671             }
 672             /* we need to buffer, because only the chunk as whole can be
 673              * inflated. */
 674             ret = bdrv_co_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
 675                                 s->compressed_chunk, 0);
 676             if (ret < 0) {
 677                 return -1;
 678             }
 679
 680             ret = dmg_uncompress_bz2((char *)s->compressed_chunk,
 681                                      (unsigned int) s->lengths[chunk],
 682                                      (char *)s->uncompressed_chunk,
 683                                      (unsigned int)
 684                                          (512 * s->sectorcounts[chunk]));
 685             if (ret < 0) {
 686                 return ret;
 687             }
 688             break;
 689         case ULFO:
 690             if (!dmg_uncompress_lzfse) {
 691                 break;
 692             }
 693             /* we need to buffer, because only the chunk as whole can be
 694              * inflated. */
 695             ret = bdrv_co_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
 696                                 s->compressed_chunk, 0);
 697             if (ret < 0) {
 698                 return -1;
 699             }
 700
 701             ret = dmg_uncompress_lzfse((char *)s->compressed_chunk,
 702                                        (unsigned int) s->lengths[chunk],
 703                                        (char *)s->uncompressed_chunk,
 704                                        (unsigned int)
 705                                            (512 * s->sectorcounts[chunk]));
 706             if (ret < 0) {
 707                 return ret;
 708             }
 709             break;
 710         case UDRW: /* copy */
 711             ret = bdrv_co_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
 712                                 s->uncompressed_chunk, 0);
 713             if (ret < 0) {
 714                 return -1;
 715             }
 716             break;
 717         case UDZE: /* zeros */
 718         case UDIG: /* ignore */
 719             /* see dmg_read, it is treated specially. No buffer needs to be
 720              * pre-filled, the zeroes can be set directly. */
 721             break;
 722         }
 723         s->current_chunk = chunk;
 724     }
 725     return 0;
 726 }
 727
 728 static int coroutine_fn GRAPH_RDLOCK
 729 dmg_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
 730               QEMUIOVector *qiov, BdrvRequestFlags flags)
 731 {
 732     BDRVDMGState *s = bs->opaque;
 733     uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
 734     int nb_sectors = bytes >> BDRV_SECTOR_BITS;
 735     int ret, i;
 736
 737     assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
 738     assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
 739
 740     qemu_co_mutex_lock(&s->lock);
 741
 742     for (i = 0; i < nb_sectors; i++) {
 743         uint32_t sector_offset_in_chunk;
 744         void *data;
 745
 746         if (dmg_read_chunk(bs, sector_num + i) != 0) {
 747             ret = -EIO;
 748             goto fail;
 749         }
 750         /* Special case: current chunk is all zeroes. Do not perform a memcpy as
 751          * s->uncompressed_chunk may be too small to cover the large all-zeroes
 752          * section. dmg_read_chunk is called to find s->current_chunk */
 753         if (s->types[s->current_chunk] == UDZE
 754             || s->types[s->current_chunk] == UDIG) { /* all zeroes block entry */
 755             qemu_iovec_memset(qiov, i * 512, 0, 512);
 756             continue;
 757         }
 758         sector_offset_in_chunk = sector_num + i - s->sectors[s->current_chunk];
 759         data = s->uncompressed_chunk + sector_offset_in_chunk * 512;
 760         qemu_iovec_from_buf(qiov, i * 512, data, 512);
 761     }
 762
 763     ret = 0;
 764 fail:
 765     qemu_co_mutex_unlock(&s->lock);
 766     return ret;
 767 }
 768
 769 static void dmg_close(BlockDriverState *bs)
 770 {
 771     BDRVDMGState *s = bs->opaque;
 772
 773     g_free(s->types);
 774     g_free(s->offsets);
 775     g_free(s->lengths);
 776     g_free(s->sectors);
 777     g_free(s->sectorcounts);
 778     qemu_vfree(s->compressed_chunk);
 779     qemu_vfree(s->uncompressed_chunk);
 780
 781     inflateEnd(&s->zstream);
 782 }
 783
 784 static BlockDriver bdrv_dmg = {
 785     .format_name    = "dmg",
 786     .instance_size  = sizeof(BDRVDMGState),
 787     .bdrv_probe     = dmg_probe,
 788     .bdrv_open      = dmg_open,
 789     .bdrv_refresh_limits = dmg_refresh_limits,
 790     .bdrv_child_perm     = bdrv_default_perms,
 791     .bdrv_co_preadv = dmg_co_preadv,
 792     .bdrv_close     = dmg_close,
 793     .is_format      = true,
 794 };
 795
 796 static void bdrv_dmg_init(void)
 797 {
 798     bdrv_register(&bdrv_dmg);
 799 }
 800
 801 block_init(bdrv_dmg_init);