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qemu/block/dmg.c

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/*
* 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_int.h"
#include "bswap.h"
#include "module.h"
#include <zlib.h>
typedef struct BDRVDMGState {
/* 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;
} BDRVDMGState;
static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
{
int len=strlen(filename);
if(len>4 && !strcmp(filename+len-4,".dmg"))
return 2;
return 0;
}
static off_t read_off(BlockDriverState *bs, int64_t offset)
{
uint64_t buffer;
if (bdrv_pread(bs->file, offset, &buffer, 8) < 8)
return 0;
return be64_to_cpu(buffer);
}
static off_t read_uint32(BlockDriverState *bs, int64_t offset)
{
uint32_t buffer;
if (bdrv_pread(bs->file, offset, &buffer, 4) < 4)
return 0;
return be32_to_cpu(buffer);
}
static int dmg_open(BlockDriverState *bs, int flags)
{
BDRVDMGState *s = bs->opaque;
off_t info_begin,info_end,last_in_offset,last_out_offset;
uint32_t count;
uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
int64_t offset;
bs->read_only = 1;
s->n_chunks = 0;
s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
/* read offset of info blocks */
offset = bdrv_getlength(bs->file);
if (offset < 0) {
goto fail;
}
offset -= 0x1d8;
info_begin = read_off(bs, offset);
if (info_begin == 0) {
goto fail;
}
if (read_uint32(bs, info_begin) != 0x100) {
goto fail;
}
count = read_uint32(bs, info_begin + 4);
if (count == 0) {
goto fail;
}
info_end = info_begin + count;
offset = info_begin + 0x100;
/* read offsets */
last_in_offset = last_out_offset = 0;
while (offset < info_end) {
uint32_t type;
count = read_uint32(bs, offset);
if(count==0)
goto fail;
offset += 4;
type = read_uint32(bs, offset);
if (type == 0x6d697368 && count >= 244) {
int new_size, chunk_count;
offset += 4;
offset += 200;
chunk_count = (count-204)/40;
new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
s->types = qemu_realloc(s->types, new_size/2);
s->offsets = qemu_realloc(s->offsets, new_size);
s->lengths = qemu_realloc(s->lengths, new_size);
s->sectors = qemu_realloc(s->sectors, new_size);
s->sectorcounts = qemu_realloc(s->sectorcounts, new_size);
for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) {
s->types[i] = read_uint32(bs, offset);
offset += 4;
if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
if(s->types[i]==0xffffffff) {
last_in_offset = s->offsets[i-1]+s->lengths[i-1];
last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1];
}
chunk_count--;
i--;
offset += 36;
continue;
}
offset += 4;
s->sectors[i] = last_out_offset+read_off(bs, offset);
offset += 8;
s->sectorcounts[i] = read_off(bs, offset);
offset += 8;
s->offsets[i] = last_in_offset+read_off(bs, offset);
offset += 8;
s->lengths[i] = read_off(bs, offset);
offset += 8;
if(s->lengths[i]>max_compressed_size)
max_compressed_size = s->lengths[i];
if(s->sectorcounts[i]>max_sectors_per_chunk)
max_sectors_per_chunk = s->sectorcounts[i];
}
s->n_chunks+=chunk_count;
}
}
/* initialize zlib engine */
s->compressed_chunk = qemu_malloc(max_compressed_size+1);
s->uncompressed_chunk = qemu_malloc(512*max_sectors_per_chunk);
if(inflateInit(&s->zstream) != Z_OK)
goto fail;
s->current_chunk = s->n_chunks;
return 0;
fail:
return -1;
}
static inline int is_sector_in_chunk(BDRVDMGState* s,
uint32_t chunk_num,int 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,int 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, int 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);
if(chunk>=s->n_chunks)
return -1;
s->current_chunk = s->n_chunks;
switch(s->types[chunk]) {
case 0x80000005: { /* zlib compressed */
int i;
/* we need to buffer, because only the chunk as whole can be
* inflated. */
i=0;
do {
ret = bdrv_pread(bs->file, s->offsets[chunk] + i,
s->compressed_chunk+i, s->lengths[chunk]-i);
if(ret<0 && errno==EINTR)
ret=0;
i+=ret;
} while(ret>=0 && ret+i<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; }
case 1: /* copy */
ret = bdrv_pread(bs->file, s->offsets[chunk],
s->uncompressed_chunk, s->lengths[chunk]);
if (ret != s->lengths[chunk])
return -1;
break;
case 2: /* zero */
memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]);
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;
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 void dmg_close(BlockDriverState *bs)
{
BDRVDMGState *s = bs->opaque;
if(s->n_chunks>0) {
free(s->types);
free(s->offsets);
free(s->lengths);
free(s->sectors);
free(s->sectorcounts);
}
free(s->compressed_chunk);
free(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_read,
.bdrv_close = dmg_close,
};
static void bdrv_dmg_init(void)
{
bdrv_register(&bdrv_dmg);
}
block_init(bdrv_dmg_init);
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