root / block / cloop.c @ 9b036055
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/*
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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 "module.h" |
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#include <zlib.h> |
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typedef struct BDRVCloopState { |
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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, 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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bs->read_only = 1;
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/* read header */
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if (bdrv_pread(bs->file, 128, &s->block_size, 4) < 4) { |
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goto cloop_close;
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} |
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s->block_size = be32_to_cpu(s->block_size); |
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if (bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4) < 4) { |
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goto cloop_close;
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} |
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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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s->offsets = qemu_malloc(offsets_size); |
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if (bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size) < |
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offsets_size) { |
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goto cloop_close;
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} |
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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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s->compressed_block = qemu_malloc(max_compressed_block_size+1);
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s->uncompressed_block = qemu_malloc(s->block_size); |
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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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cloop_close:
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return -1; |
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} |
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static inline int cloop_read_block(BlockDriverState *bs, int block_num) |
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{ |
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BDRVCloopState *s = bs->opaque; |
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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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ret = bdrv_pread(bs->file, s->offsets[block_num], s->compressed_block, |
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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(bs, 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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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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static BlockDriver bdrv_cloop = {
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.format_name = "cloop",
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.instance_size = sizeof(BDRVCloopState),
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.bdrv_probe = cloop_probe, |
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.bdrv_open = cloop_open, |
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.bdrv_read = cloop_read, |
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.bdrv_close = cloop_close, |
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}; |
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static void bdrv_cloop_init(void) |
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{ |
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bdrv_register(&bdrv_cloop); |
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} |
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block_init(bdrv_cloop_init); |