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