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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 "vl.h"
#include "block_int.h"
#include "bswap.h"
#include <zlib.h>
typedef struct BDRVDMGState {
int fd;
/* 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;
char* compressed_chunk;
char* 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(int fd)
{
uint64_t buffer;
if(read(fd,&buffer,8)<8)
return 0;
return be64_to_cpu(buffer);
}
static off_t read_uint32(int fd)
{
uint32_t buffer;
if(read(fd,&buffer,4)<4)
return 0;
return be32_to_cpu(buffer);
}
static int dmg_open(BlockDriverState *bs, const char *filename)
{
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;
s->fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
if (s->fd < 0)
return -1;
bs->read_only = 1;
s->n_chunks = 0;
s->offsets = s->lengths = s->sectors = s->sectorcounts = 0;
/* read offset of info blocks */
if(lseek(s->fd,-0x1d8,SEEK_END)<0) {
dmg_close:
close(s->fd);
return -1;
}
info_begin=read_off(s->fd);
if(info_begin==0)
goto dmg_close;
if(lseek(s->fd,info_begin,SEEK_SET)<0)
goto dmg_close;
if(read_uint32(s->fd)!=0x100)
goto dmg_close;
if((count = read_uint32(s->fd))==0)
goto dmg_close;
info_end = info_begin+count;
if(lseek(s->fd,0xf8,SEEK_CUR)<0)
goto dmg_close;
/* read offsets */
last_in_offset = last_out_offset = 0;
while(lseek(s->fd,0,SEEK_CUR)<info_end) {
uint32_t type;
count = read_uint32(s->fd);
if(count==0)
goto dmg_close;
type = read_uint32(s->fd);
if(type!=0x6d697368 || count<244)
lseek(s->fd,count-4,SEEK_CUR);
else {
int new_size, chunk_count;
if(lseek(s->fd,200,SEEK_CUR)<0)
goto dmg_close;
chunk_count = (count-204)/40;
new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
s->types = realloc(s->types, new_size/2);
s->offsets = realloc(s->offsets, new_size);
s->lengths = realloc(s->lengths, new_size);
s->sectors = realloc(s->sectors, new_size);
s->sectorcounts = realloc(s->sectorcounts, new_size);
for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) {
s->types[i] = read_uint32(s->fd);
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--;
if(lseek(s->fd,36,SEEK_CUR)<0)
goto dmg_close;
continue;
}
read_uint32(s->fd);
s->sectors[i] = last_out_offset+read_off(s->fd);
s->sectorcounts[i] = read_off(s->fd);
s->offsets[i] = last_in_offset+read_off(s->fd);
s->lengths[i] = read_off(s->fd);
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 */
if(!(s->compressed_chunk=(char*)malloc(max_compressed_size+1)))
goto dmg_close;
if(!(s->uncompressed_chunk=(char*)malloc(512*max_sectors_per_chunk)))
goto dmg_close;
if(inflateInit(&s->zstream) != Z_OK)
goto dmg_close;
s->current_chunk = s->n_chunks;
return 0;
}
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(BDRVDMGState *s,int sector_num)
{
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;
ret = lseek(s->fd, s->offsets[chunk], SEEK_SET);
if(ret<0)
return -1;
/* we need to buffer, because only the chunk as whole can be
* inflated. */
i=0;
do {
ret = read(s->fd, 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 = read(s->fd, 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(s, 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;
close(s->fd);
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);
}
BlockDriver bdrv_dmg = {
"dmg",
sizeof(BDRVDMGState),
dmg_probe,
dmg_open,
dmg_read,
NULL,
dmg_close,
};
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