170 lines
4.8 KiB
C
170 lines
4.8 KiB
C
/*
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* QEMU Block driver for CLOOP 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 "qemu-common.h"
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#include "block_int.h"
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#include <zlib.h>
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typedef struct BDRVCloopState {
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int fd;
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uint32_t block_size;
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uint32_t n_blocks;
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uint64_t* offsets;
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uint32_t sectors_per_block;
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uint32_t current_block;
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uint8_t *compressed_block;
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uint8_t *uncompressed_block;
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z_stream zstream;
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} BDRVCloopState;
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static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename)
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{
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const char* magic_version_2_0="#!/bin/sh\n"
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"#V2.0 Format\n"
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"modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n";
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int length=strlen(magic_version_2_0);
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if(length>buf_size)
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length=buf_size;
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if(!memcmp(magic_version_2_0,buf,length))
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return 2;
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return 0;
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}
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static int cloop_open(BlockDriverState *bs, const char *filename, int flags)
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{
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BDRVCloopState *s = bs->opaque;
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uint32_t offsets_size,max_compressed_block_size=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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/* read header */
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if(lseek(s->fd,128,SEEK_SET)<0) {
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cloop_close:
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close(s->fd);
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return -1;
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}
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if(read(s->fd,&s->block_size,4)<4)
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goto cloop_close;
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s->block_size=be32_to_cpu(s->block_size);
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if(read(s->fd,&s->n_blocks,4)<4)
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goto cloop_close;
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s->n_blocks=be32_to_cpu(s->n_blocks);
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/* read offsets */
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offsets_size=s->n_blocks*sizeof(uint64_t);
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if(!(s->offsets=(uint64_t*)malloc(offsets_size)))
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goto cloop_close;
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if(read(s->fd,s->offsets,offsets_size)<offsets_size)
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goto cloop_close;
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for(i=0;i<s->n_blocks;i++) {
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s->offsets[i]=be64_to_cpu(s->offsets[i]);
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if(i>0) {
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uint32_t size=s->offsets[i]-s->offsets[i-1];
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if(size>max_compressed_block_size)
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max_compressed_block_size=size;
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}
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}
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/* initialize zlib engine */
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if(!(s->compressed_block = malloc(max_compressed_block_size+1)))
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goto cloop_close;
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if(!(s->uncompressed_block = malloc(s->block_size)))
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goto cloop_close;
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if(inflateInit(&s->zstream) != Z_OK)
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goto cloop_close;
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s->current_block=s->n_blocks;
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s->sectors_per_block = s->block_size/512;
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bs->total_sectors = s->n_blocks*s->sectors_per_block;
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return 0;
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}
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static inline int cloop_read_block(BDRVCloopState *s,int block_num)
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{
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if(s->current_block != block_num) {
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int ret;
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uint32_t bytes = s->offsets[block_num+1]-s->offsets[block_num];
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lseek(s->fd, s->offsets[block_num], SEEK_SET);
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ret = read(s->fd, s->compressed_block, bytes);
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if (ret != bytes)
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return -1;
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s->zstream.next_in = s->compressed_block;
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s->zstream.avail_in = bytes;
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s->zstream.next_out = s->uncompressed_block;
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s->zstream.avail_out = s->block_size;
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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 != s->block_size)
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return -1;
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s->current_block = block_num;
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}
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return 0;
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}
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static int cloop_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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BDRVCloopState *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_block=((sector_num+i)%s->sectors_per_block),
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block_num=(sector_num+i)/s->sectors_per_block;
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if(cloop_read_block(s, block_num) != 0)
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return -1;
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memcpy(buf+i*512,s->uncompressed_block+sector_offset_in_block*512,512);
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}
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return 0;
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}
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static void cloop_close(BlockDriverState *bs)
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{
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BDRVCloopState *s = bs->opaque;
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close(s->fd);
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if(s->n_blocks>0)
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free(s->offsets);
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free(s->compressed_block);
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free(s->uncompressed_block);
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inflateEnd(&s->zstream);
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}
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BlockDriver bdrv_cloop = {
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"cloop",
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sizeof(BDRVCloopState),
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cloop_probe,
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cloop_open,
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cloop_read,
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NULL,
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cloop_close,
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};
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