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https://gitlab.com/qemu-project/qemu
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![ths](/assets/img/avatar_default.png)
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3173 c046a42c-6fe2-441c-8c8c-71466251a162
298 lines
8.1 KiB
C
298 lines
8.1 KiB
C
/*
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* QEMU Block driver for DMG images
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*
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* Copyright (c) 2004 Johannes E. Schindelin
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "vl.h"
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#include "block_int.h"
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#include "bswap.h"
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#include <zlib.h>
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typedef struct BDRVDMGState {
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int fd;
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/* each chunk contains a certain number of sectors,
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* offsets[i] is the offset in the .dmg file,
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* lengths[i] is the length of the compressed chunk,
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* sectors[i] is the sector beginning at offsets[i],
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* sectorcounts[i] is the number of sectors in that chunk,
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* the sectors array is ordered
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* 0<=i<n_chunks */
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uint32_t n_chunks;
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uint32_t* types;
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uint64_t* offsets;
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uint64_t* lengths;
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uint64_t* sectors;
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uint64_t* sectorcounts;
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uint32_t current_chunk;
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uint8_t *compressed_chunk;
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uint8_t *uncompressed_chunk;
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z_stream zstream;
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} BDRVDMGState;
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static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
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{
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int len=strlen(filename);
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if(len>4 && !strcmp(filename+len-4,".dmg"))
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return 2;
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return 0;
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}
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static off_t read_off(int fd)
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{
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uint64_t buffer;
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if(read(fd,&buffer,8)<8)
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return 0;
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return be64_to_cpu(buffer);
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}
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static off_t read_uint32(int fd)
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{
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uint32_t buffer;
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if(read(fd,&buffer,4)<4)
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return 0;
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return be32_to_cpu(buffer);
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}
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static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
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{
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BDRVDMGState *s = bs->opaque;
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off_t info_begin,info_end,last_in_offset,last_out_offset;
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uint32_t count;
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uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
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s->fd = open(filename, O_RDONLY | O_BINARY);
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if (s->fd < 0)
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return -errno;
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bs->read_only = 1;
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s->n_chunks = 0;
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s->offsets = s->lengths = s->sectors = s->sectorcounts = 0;
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/* read offset of info blocks */
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if(lseek(s->fd,-0x1d8,SEEK_END)<0) {
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dmg_close:
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close(s->fd);
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/* open raw instead */
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bs->drv=&bdrv_raw;
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return bs->drv->bdrv_open(bs, filename, flags);
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}
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info_begin=read_off(s->fd);
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if(info_begin==0)
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goto dmg_close;
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if(lseek(s->fd,info_begin,SEEK_SET)<0)
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goto dmg_close;
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if(read_uint32(s->fd)!=0x100)
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goto dmg_close;
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if((count = read_uint32(s->fd))==0)
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goto dmg_close;
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info_end = info_begin+count;
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if(lseek(s->fd,0xf8,SEEK_CUR)<0)
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goto dmg_close;
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/* read offsets */
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last_in_offset = last_out_offset = 0;
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while(lseek(s->fd,0,SEEK_CUR)<info_end) {
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uint32_t type;
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count = read_uint32(s->fd);
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if(count==0)
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goto dmg_close;
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type = read_uint32(s->fd);
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if(type!=0x6d697368 || count<244)
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lseek(s->fd,count-4,SEEK_CUR);
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else {
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int new_size, chunk_count;
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if(lseek(s->fd,200,SEEK_CUR)<0)
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goto dmg_close;
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chunk_count = (count-204)/40;
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new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
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s->types = realloc(s->types, new_size/2);
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s->offsets = realloc(s->offsets, new_size);
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s->lengths = realloc(s->lengths, new_size);
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s->sectors = realloc(s->sectors, new_size);
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s->sectorcounts = realloc(s->sectorcounts, new_size);
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for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) {
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s->types[i] = read_uint32(s->fd);
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if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
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if(s->types[i]==0xffffffff) {
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last_in_offset = s->offsets[i-1]+s->lengths[i-1];
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last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1];
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}
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chunk_count--;
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i--;
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if(lseek(s->fd,36,SEEK_CUR)<0)
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goto dmg_close;
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continue;
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}
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read_uint32(s->fd);
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s->sectors[i] = last_out_offset+read_off(s->fd);
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s->sectorcounts[i] = read_off(s->fd);
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s->offsets[i] = last_in_offset+read_off(s->fd);
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s->lengths[i] = read_off(s->fd);
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if(s->lengths[i]>max_compressed_size)
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max_compressed_size = s->lengths[i];
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if(s->sectorcounts[i]>max_sectors_per_chunk)
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max_sectors_per_chunk = s->sectorcounts[i];
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}
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s->n_chunks+=chunk_count;
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}
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}
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/* initialize zlib engine */
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if(!(s->compressed_chunk = malloc(max_compressed_size+1)))
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goto dmg_close;
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if(!(s->uncompressed_chunk = malloc(512*max_sectors_per_chunk)))
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goto dmg_close;
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if(inflateInit(&s->zstream) != Z_OK)
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goto dmg_close;
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s->current_chunk = s->n_chunks;
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return 0;
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}
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static inline int is_sector_in_chunk(BDRVDMGState* s,
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uint32_t chunk_num,int sector_num)
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{
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if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num ||
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s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num)
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return 0;
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else
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return -1;
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}
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static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
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{
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/* binary search */
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uint32_t chunk1=0,chunk2=s->n_chunks,chunk3;
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while(chunk1!=chunk2) {
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chunk3 = (chunk1+chunk2)/2;
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if(s->sectors[chunk3]>sector_num)
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chunk2 = chunk3;
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else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num)
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return chunk3;
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else
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chunk1 = chunk3;
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}
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return s->n_chunks; /* error */
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}
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static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
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{
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if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
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int ret;
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uint32_t chunk = search_chunk(s,sector_num);
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if(chunk>=s->n_chunks)
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return -1;
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s->current_chunk = s->n_chunks;
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switch(s->types[chunk]) {
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case 0x80000005: { /* zlib compressed */
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int i;
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ret = lseek(s->fd, s->offsets[chunk], SEEK_SET);
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if(ret<0)
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return -1;
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/* we need to buffer, because only the chunk as whole can be
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* inflated. */
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i=0;
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do {
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ret = read(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i);
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if(ret<0 && errno==EINTR)
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ret=0;
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i+=ret;
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} while(ret>=0 && ret+i<s->lengths[chunk]);
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if (ret != s->lengths[chunk])
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return -1;
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s->zstream.next_in = s->compressed_chunk;
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s->zstream.avail_in = s->lengths[chunk];
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s->zstream.next_out = s->uncompressed_chunk;
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s->zstream.avail_out = 512*s->sectorcounts[chunk];
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ret = inflateReset(&s->zstream);
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if(ret != Z_OK)
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return -1;
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ret = inflate(&s->zstream, Z_FINISH);
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if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk])
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return -1;
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break; }
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case 1: /* copy */
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ret = read(s->fd, s->uncompressed_chunk, s->lengths[chunk]);
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if (ret != s->lengths[chunk])
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return -1;
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break;
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case 2: /* zero */
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memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]);
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break;
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}
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s->current_chunk = chunk;
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}
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return 0;
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}
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static int dmg_read(BlockDriverState *bs, int64_t sector_num,
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uint8_t *buf, int nb_sectors)
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{
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BDRVDMGState *s = bs->opaque;
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int i;
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for(i=0;i<nb_sectors;i++) {
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uint32_t sector_offset_in_chunk;
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if(dmg_read_chunk(s, sector_num+i) != 0)
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return -1;
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sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
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memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
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}
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return 0;
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}
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static void dmg_close(BlockDriverState *bs)
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{
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BDRVDMGState *s = bs->opaque;
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close(s->fd);
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if(s->n_chunks>0) {
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free(s->types);
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free(s->offsets);
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free(s->lengths);
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free(s->sectors);
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free(s->sectorcounts);
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}
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free(s->compressed_chunk);
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free(s->uncompressed_chunk);
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inflateEnd(&s->zstream);
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}
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BlockDriver bdrv_dmg = {
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"dmg",
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sizeof(BDRVDMGState),
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dmg_probe,
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dmg_open,
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dmg_read,
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NULL,
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dmg_close,
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};
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