diff options
Diffstat (limited to 'src/block/dmg.c')
| -rw-r--r-- | src/block/dmg.c | 725 |
1 files changed, 725 insertions, 0 deletions
diff --git a/src/block/dmg.c b/src/block/dmg.c new file mode 100644 index 0000000..546a6f5 --- /dev/null +++ b/src/block/dmg.c @@ -0,0 +1,725 @@ +/* + * QEMU Block driver for DMG images + * + * Copyright (c) 2004 Johannes E. Schindelin + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ +#include "qemu-common.h" +#include "block/block_int.h" +#include "qemu/bswap.h" +#include "qemu/error-report.h" +#include "qemu/module.h" +#include <zlib.h> +#ifdef CONFIG_BZIP2 +#include <bzlib.h> +#endif +#include <glib.h> + +enum { + /* Limit chunk sizes to prevent unreasonable amounts of memory being used + * or truncating when converting to 32-bit types + */ + DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */ + DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512, +}; + +typedef struct BDRVDMGState { + CoMutex lock; + /* each chunk contains a certain number of sectors, + * offsets[i] is the offset in the .dmg file, + * lengths[i] is the length of the compressed chunk, + * sectors[i] is the sector beginning at offsets[i], + * sectorcounts[i] is the number of sectors in that chunk, + * the sectors array is ordered + * 0<=i<n_chunks */ + + uint32_t n_chunks; + uint32_t* types; + uint64_t* offsets; + uint64_t* lengths; + uint64_t* sectors; + uint64_t* sectorcounts; + uint32_t current_chunk; + uint8_t *compressed_chunk; + uint8_t *uncompressed_chunk; + z_stream zstream; +#ifdef CONFIG_BZIP2 + bz_stream bzstream; +#endif +} BDRVDMGState; + +static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename) +{ + int len; + + if (!filename) { + return 0; + } + + len = strlen(filename); + if (len > 4 && !strcmp(filename + len - 4, ".dmg")) { + return 2; + } + return 0; +} + +static int read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result) +{ + uint64_t buffer; + int ret; + + ret = bdrv_pread(bs->file->bs, offset, &buffer, 8); + if (ret < 0) { + return ret; + } + + *result = be64_to_cpu(buffer); + return 0; +} + +static int read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result) +{ + uint32_t buffer; + int ret; + + ret = bdrv_pread(bs->file->bs, offset, &buffer, 4); + if (ret < 0) { + return ret; + } + + *result = be32_to_cpu(buffer); + return 0; +} + +static inline uint64_t buff_read_uint64(const uint8_t *buffer, int64_t offset) +{ + return be64_to_cpu(*(uint64_t *)&buffer[offset]); +} + +static inline uint32_t buff_read_uint32(const uint8_t *buffer, int64_t offset) +{ + return be32_to_cpu(*(uint32_t *)&buffer[offset]); +} + +/* Increase max chunk sizes, if necessary. This function is used to calculate + * the buffer sizes needed for compressed/uncompressed chunk I/O. + */ +static void update_max_chunk_size(BDRVDMGState *s, uint32_t chunk, + uint32_t *max_compressed_size, + uint32_t *max_sectors_per_chunk) +{ + uint32_t compressed_size = 0; + uint32_t uncompressed_sectors = 0; + + switch (s->types[chunk]) { + case 0x80000005: /* zlib compressed */ + case 0x80000006: /* bzip2 compressed */ + compressed_size = s->lengths[chunk]; + uncompressed_sectors = s->sectorcounts[chunk]; + break; + case 1: /* copy */ + uncompressed_sectors = (s->lengths[chunk] + 511) / 512; + break; + case 2: /* zero */ + /* as the all-zeroes block may be large, it is treated specially: the + * sector is not copied from a large buffer, a simple memset is used + * instead. Therefore uncompressed_sectors does not need to be set. */ + break; + } + + if (compressed_size > *max_compressed_size) { + *max_compressed_size = compressed_size; + } + if (uncompressed_sectors > *max_sectors_per_chunk) { + *max_sectors_per_chunk = uncompressed_sectors; + } +} + +static int64_t dmg_find_koly_offset(BlockDriverState *file_bs, Error **errp) +{ + int64_t length; + int64_t offset = 0; + uint8_t buffer[515]; + int i, ret; + + /* bdrv_getlength returns a multiple of block size (512), rounded up. Since + * dmg images can have odd sizes, try to look for the "koly" magic which + * marks the begin of the UDIF trailer (512 bytes). This magic can be found + * in the last 511 bytes of the second-last sector or the first 4 bytes of + * the last sector (search space: 515 bytes) */ + length = bdrv_getlength(file_bs); + if (length < 0) { + error_setg_errno(errp, -length, + "Failed to get file size while reading UDIF trailer"); + return length; + } else if (length < 512) { + error_setg(errp, "dmg file must be at least 512 bytes long"); + return -EINVAL; + } + if (length > 511 + 512) { + offset = length - 511 - 512; + } + length = length < 515 ? length : 515; + ret = bdrv_pread(file_bs, offset, buffer, length); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed while reading UDIF trailer"); + return ret; + } + for (i = 0; i < length - 3; i++) { + if (buffer[i] == 'k' && buffer[i+1] == 'o' && + buffer[i+2] == 'l' && buffer[i+3] == 'y') { + return offset + i; + } + } + error_setg(errp, "Could not locate UDIF trailer in dmg file"); + return -EINVAL; +} + +/* used when building the sector table */ +typedef struct DmgHeaderState { + /* used internally by dmg_read_mish_block to remember offsets of blocks + * across calls */ + uint64_t data_fork_offset; + /* exported for dmg_open */ + uint32_t max_compressed_size; + uint32_t max_sectors_per_chunk; +} DmgHeaderState; + +static bool dmg_is_known_block_type(uint32_t entry_type) +{ + switch (entry_type) { + case 0x00000001: /* uncompressed */ + case 0x00000002: /* zeroes */ + case 0x80000005: /* zlib */ +#ifdef CONFIG_BZIP2 + case 0x80000006: /* bzip2 */ +#endif + return true; + default: + return false; + } +} + +static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds, + uint8_t *buffer, uint32_t count) +{ + uint32_t type, i; + int ret; + size_t new_size; + uint32_t chunk_count; + int64_t offset = 0; + uint64_t data_offset; + uint64_t in_offset = ds->data_fork_offset; + uint64_t out_offset; + + type = buff_read_uint32(buffer, offset); + /* skip data that is not a valid MISH block (invalid magic or too small) */ + if (type != 0x6d697368 || count < 244) { + /* assume success for now */ + return 0; + } + + /* chunk offsets are relative to this sector number */ + out_offset = buff_read_uint64(buffer, offset + 8); + + /* location in data fork for (compressed) blob (in bytes) */ + data_offset = buff_read_uint64(buffer, offset + 0x18); + in_offset += data_offset; + + /* move to begin of chunk entries */ + offset += 204; + + chunk_count = (count - 204) / 40; + new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); + s->types = g_realloc(s->types, new_size / 2); + s->offsets = g_realloc(s->offsets, new_size); + s->lengths = g_realloc(s->lengths, new_size); + s->sectors = g_realloc(s->sectors, new_size); + s->sectorcounts = g_realloc(s->sectorcounts, new_size); + + for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) { + s->types[i] = buff_read_uint32(buffer, offset); + if (!dmg_is_known_block_type(s->types[i])) { + chunk_count--; + i--; + offset += 40; + continue; + } + + /* sector number */ + s->sectors[i] = buff_read_uint64(buffer, offset + 8); + s->sectors[i] += out_offset; + + /* sector count */ + s->sectorcounts[i] = buff_read_uint64(buffer, offset + 0x10); + + /* all-zeroes sector (type 2) does not need to be "uncompressed" and can + * therefore be unbounded. */ + if (s->types[i] != 2 && s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) { + error_report("sector count %" PRIu64 " for chunk %" PRIu32 + " is larger than max (%u)", + s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX); + ret = -EINVAL; + goto fail; + } + + /* offset in (compressed) data fork */ + s->offsets[i] = buff_read_uint64(buffer, offset + 0x18); + s->offsets[i] += in_offset; + + /* length in (compressed) data fork */ + s->lengths[i] = buff_read_uint64(buffer, offset + 0x20); + + if (s->lengths[i] > DMG_LENGTHS_MAX) { + error_report("length %" PRIu64 " for chunk %" PRIu32 + " is larger than max (%u)", + s->lengths[i], i, DMG_LENGTHS_MAX); + ret = -EINVAL; + goto fail; + } + + update_max_chunk_size(s, i, &ds->max_compressed_size, + &ds->max_sectors_per_chunk); + offset += 40; + } + s->n_chunks += chunk_count; + return 0; + +fail: + return ret; +} + +static int dmg_read_resource_fork(BlockDriverState *bs, DmgHeaderState *ds, + uint64_t info_begin, uint64_t info_length) +{ + BDRVDMGState *s = bs->opaque; + int ret; + uint32_t count, rsrc_data_offset; + uint8_t *buffer = NULL; + uint64_t info_end; + uint64_t offset; + + /* read offset from begin of resource fork (info_begin) to resource data */ + ret = read_uint32(bs, info_begin, &rsrc_data_offset); + if (ret < 0) { + goto fail; + } else if (rsrc_data_offset > info_length) { + ret = -EINVAL; + goto fail; + } + + /* read length of resource data */ + ret = read_uint32(bs, info_begin + 8, &count); + if (ret < 0) { + goto fail; + } else if (count == 0 || rsrc_data_offset + count > info_length) { + ret = -EINVAL; + goto fail; + } + + /* begin of resource data (consisting of one or more resources) */ + offset = info_begin + rsrc_data_offset; + + /* end of resource data (there is possibly a following resource map + * which will be ignored). */ + info_end = offset + count; + + /* read offsets (mish blocks) from one or more resources in resource data */ + while (offset < info_end) { + /* size of following resource */ + ret = read_uint32(bs, offset, &count); + if (ret < 0) { + goto fail; + } else if (count == 0 || count > info_end - offset) { + ret = -EINVAL; + goto fail; + } + offset += 4; + + buffer = g_realloc(buffer, count); + ret = bdrv_pread(bs->file->bs, offset, buffer, count); + if (ret < 0) { + goto fail; + } + + ret = dmg_read_mish_block(s, ds, buffer, count); + if (ret < 0) { + goto fail; + } + /* advance offset by size of resource */ + offset += count; + } + ret = 0; + +fail: + g_free(buffer); + return ret; +} + +static int dmg_read_plist_xml(BlockDriverState *bs, DmgHeaderState *ds, + uint64_t info_begin, uint64_t info_length) +{ + BDRVDMGState *s = bs->opaque; + int ret; + uint8_t *buffer = NULL; + char *data_begin, *data_end; + + /* Have at least some length to avoid NULL for g_malloc. Attempt to set a + * safe upper cap on the data length. A test sample had a XML length of + * about 1 MiB. */ + if (info_length == 0 || info_length > 16 * 1024 * 1024) { + ret = -EINVAL; + goto fail; + } + + buffer = g_malloc(info_length + 1); + buffer[info_length] = '\0'; + ret = bdrv_pread(bs->file->bs, info_begin, buffer, info_length); + if (ret != info_length) { + ret = -EINVAL; + goto fail; + } + + /* look for <data>...</data>. The data is 284 (0x11c) bytes after base64 + * decode. The actual data element has 431 (0x1af) bytes which includes tabs + * and line feeds. */ + data_end = (char *)buffer; + while ((data_begin = strstr(data_end, "<data>")) != NULL) { + guchar *mish; + gsize out_len = 0; + + data_begin += 6; + data_end = strstr(data_begin, "</data>"); + /* malformed XML? */ + if (data_end == NULL) { + ret = -EINVAL; + goto fail; + } + *data_end++ = '\0'; + mish = g_base64_decode(data_begin, &out_len); + ret = dmg_read_mish_block(s, ds, mish, (uint32_t)out_len); + g_free(mish); + if (ret < 0) { + goto fail; + } + } + ret = 0; + +fail: + g_free(buffer); + return ret; +} + +static int dmg_open(BlockDriverState *bs, QDict *options, int flags, + Error **errp) +{ + BDRVDMGState *s = bs->opaque; + DmgHeaderState ds; + uint64_t rsrc_fork_offset, rsrc_fork_length; + uint64_t plist_xml_offset, plist_xml_length; + int64_t offset; + int ret; + + bs->read_only = 1; + s->n_chunks = 0; + s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL; + /* used by dmg_read_mish_block to keep track of the current I/O position */ + ds.data_fork_offset = 0; + ds.max_compressed_size = 1; + ds.max_sectors_per_chunk = 1; + + /* locate the UDIF trailer */ + offset = dmg_find_koly_offset(bs->file->bs, errp); + if (offset < 0) { + ret = offset; + goto fail; + } + + /* offset of data fork (DataForkOffset) */ + ret = read_uint64(bs, offset + 0x18, &ds.data_fork_offset); + if (ret < 0) { + goto fail; + } else if (ds.data_fork_offset > offset) { + ret = -EINVAL; + goto fail; + } + + /* offset of resource fork (RsrcForkOffset) */ + ret = read_uint64(bs, offset + 0x28, &rsrc_fork_offset); + if (ret < 0) { + goto fail; + } + ret = read_uint64(bs, offset + 0x30, &rsrc_fork_length); + if (ret < 0) { + goto fail; + } + if (rsrc_fork_offset >= offset || + rsrc_fork_length > offset - rsrc_fork_offset) { + ret = -EINVAL; + goto fail; + } + /* offset of property list (XMLOffset) */ + ret = read_uint64(bs, offset + 0xd8, &plist_xml_offset); + if (ret < 0) { + goto fail; + } + ret = read_uint64(bs, offset + 0xe0, &plist_xml_length); + if (ret < 0) { + goto fail; + } + if (plist_xml_offset >= offset || + plist_xml_length > offset - plist_xml_offset) { + ret = -EINVAL; + goto fail; + } + ret = read_uint64(bs, offset + 0x1ec, (uint64_t *)&bs->total_sectors); + if (ret < 0) { + goto fail; + } + if (bs->total_sectors < 0) { + ret = -EINVAL; + goto fail; + } + if (rsrc_fork_length != 0) { + ret = dmg_read_resource_fork(bs, &ds, + rsrc_fork_offset, rsrc_fork_length); + if (ret < 0) { + goto fail; + } + } else if (plist_xml_length != 0) { + ret = dmg_read_plist_xml(bs, &ds, plist_xml_offset, plist_xml_length); + if (ret < 0) { + goto fail; + } + } else { + ret = -EINVAL; + goto fail; + } + + /* initialize zlib engine */ + s->compressed_chunk = qemu_try_blockalign(bs->file->bs, + ds.max_compressed_size + 1); + s->uncompressed_chunk = qemu_try_blockalign(bs->file->bs, + 512 * ds.max_sectors_per_chunk); + if (s->compressed_chunk == NULL || s->uncompressed_chunk == NULL) { + ret = -ENOMEM; + goto fail; + } + + if (inflateInit(&s->zstream) != Z_OK) { + ret = -EINVAL; + goto fail; + } + + s->current_chunk = s->n_chunks; + + qemu_co_mutex_init(&s->lock); + return 0; + +fail: + g_free(s->types); + g_free(s->offsets); + g_free(s->lengths); + g_free(s->sectors); + g_free(s->sectorcounts); + qemu_vfree(s->compressed_chunk); + qemu_vfree(s->uncompressed_chunk); + return ret; +} + +static inline int is_sector_in_chunk(BDRVDMGState* s, + uint32_t chunk_num, uint64_t sector_num) +{ + if (chunk_num >= s->n_chunks || s->sectors[chunk_num] > sector_num || + s->sectors[chunk_num] + s->sectorcounts[chunk_num] <= sector_num) { + return 0; + } else { + return -1; + } +} + +static inline uint32_t search_chunk(BDRVDMGState *s, uint64_t sector_num) +{ + /* binary search */ + uint32_t chunk1 = 0, chunk2 = s->n_chunks, chunk3; + while (chunk1 != chunk2) { + chunk3 = (chunk1 + chunk2) / 2; + if (s->sectors[chunk3] > sector_num) { + chunk2 = chunk3; + } else if (s->sectors[chunk3] + s->sectorcounts[chunk3] > sector_num) { + return chunk3; + } else { + chunk1 = chunk3; + } + } + return s->n_chunks; /* error */ +} + +static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num) +{ + BDRVDMGState *s = bs->opaque; + + if (!is_sector_in_chunk(s, s->current_chunk, sector_num)) { + int ret; + uint32_t chunk = search_chunk(s, sector_num); +#ifdef CONFIG_BZIP2 + uint64_t total_out; +#endif + + if (chunk >= s->n_chunks) { + return -1; + } + + s->current_chunk = s->n_chunks; + switch (s->types[chunk]) { /* block entry type */ + case 0x80000005: { /* zlib compressed */ + /* we need to buffer, because only the chunk as whole can be + * inflated. */ + ret = bdrv_pread(bs->file->bs, s->offsets[chunk], + s->compressed_chunk, s->lengths[chunk]); + if (ret != s->lengths[chunk]) { + return -1; + } + + s->zstream.next_in = s->compressed_chunk; + s->zstream.avail_in = s->lengths[chunk]; + s->zstream.next_out = s->uncompressed_chunk; + s->zstream.avail_out = 512 * s->sectorcounts[chunk]; + ret = inflateReset(&s->zstream); + if (ret != Z_OK) { + return -1; + } + ret = inflate(&s->zstream, Z_FINISH); + if (ret != Z_STREAM_END || + s->zstream.total_out != 512 * s->sectorcounts[chunk]) { + return -1; + } + break; } +#ifdef CONFIG_BZIP2 + case 0x80000006: /* bzip2 compressed */ + /* we need to buffer, because only the chunk as whole can be + * inflated. */ + ret = bdrv_pread(bs->file->bs, s->offsets[chunk], + s->compressed_chunk, s->lengths[chunk]); + if (ret != s->lengths[chunk]) { + return -1; + } + + ret = BZ2_bzDecompressInit(&s->bzstream, 0, 0); + if (ret != BZ_OK) { + return -1; + } + s->bzstream.next_in = (char *)s->compressed_chunk; + s->bzstream.avail_in = (unsigned int) s->lengths[chunk]; + s->bzstream.next_out = (char *)s->uncompressed_chunk; + s->bzstream.avail_out = (unsigned int) 512 * s->sectorcounts[chunk]; + ret = BZ2_bzDecompress(&s->bzstream); + total_out = ((uint64_t)s->bzstream.total_out_hi32 << 32) + + s->bzstream.total_out_lo32; + BZ2_bzDecompressEnd(&s->bzstream); + if (ret != BZ_STREAM_END || + total_out != 512 * s->sectorcounts[chunk]) { + return -1; + } + break; +#endif /* CONFIG_BZIP2 */ + case 1: /* copy */ + ret = bdrv_pread(bs->file->bs, s->offsets[chunk], + s->uncompressed_chunk, s->lengths[chunk]); + if (ret != s->lengths[chunk]) { + return -1; + } + break; + case 2: /* zero */ + /* see dmg_read, it is treated specially. No buffer needs to be + * pre-filled, the zeroes can be set directly. */ + break; + } + s->current_chunk = chunk; + } + return 0; +} + +static int dmg_read(BlockDriverState *bs, int64_t sector_num, + uint8_t *buf, int nb_sectors) +{ + BDRVDMGState *s = bs->opaque; + int i; + + for (i = 0; i < nb_sectors; i++) { + uint32_t sector_offset_in_chunk; + if (dmg_read_chunk(bs, sector_num + i) != 0) { + return -1; + } + /* Special case: current chunk is all zeroes. Do not perform a memcpy as + * s->uncompressed_chunk may be too small to cover the large all-zeroes + * section. dmg_read_chunk is called to find s->current_chunk */ + if (s->types[s->current_chunk] == 2) { /* all zeroes block entry */ + memset(buf + i * 512, 0, 512); + continue; + } + sector_offset_in_chunk = sector_num + i - s->sectors[s->current_chunk]; + memcpy(buf + i * 512, + s->uncompressed_chunk + sector_offset_in_chunk * 512, 512); + } + return 0; +} + +static coroutine_fn int dmg_co_read(BlockDriverState *bs, int64_t sector_num, + uint8_t *buf, int nb_sectors) +{ + int ret; + BDRVDMGState *s = bs->opaque; + qemu_co_mutex_lock(&s->lock); + ret = dmg_read(bs, sector_num, buf, nb_sectors); + qemu_co_mutex_unlock(&s->lock); + return ret; +} + +static void dmg_close(BlockDriverState *bs) +{ + BDRVDMGState *s = bs->opaque; + + g_free(s->types); + g_free(s->offsets); + g_free(s->lengths); + g_free(s->sectors); + g_free(s->sectorcounts); + qemu_vfree(s->compressed_chunk); + qemu_vfree(s->uncompressed_chunk); + + inflateEnd(&s->zstream); +} + +static BlockDriver bdrv_dmg = { + .format_name = "dmg", + .instance_size = sizeof(BDRVDMGState), + .bdrv_probe = dmg_probe, + .bdrv_open = dmg_open, + .bdrv_read = dmg_co_read, + .bdrv_close = dmg_close, +}; + +static void bdrv_dmg_init(void) +{ + bdrv_register(&bdrv_dmg); +} + +block_init(bdrv_dmg_init); |
