diff options
Diffstat (limited to 'block/cloop.c')
| -rw-r--r-- | block/cloop.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/block/cloop.c b/block/cloop.c new file mode 100644 index 0000000000..06c687e690 --- /dev/null +++ b/block/cloop.c @@ -0,0 +1,171 @@ +/* + * QEMU Block driver for CLOOP 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 "module.h" +#include <zlib.h> + +typedef struct BDRVCloopState { + int fd; + uint32_t block_size; + uint32_t n_blocks; + uint64_t* offsets; + uint32_t sectors_per_block; + uint32_t current_block; + uint8_t *compressed_block; + uint8_t *uncompressed_block; + z_stream zstream; +} BDRVCloopState; + +static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename) +{ + const char* magic_version_2_0="#!/bin/sh\n" + "#V2.0 Format\n" + "modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n"; + int length=strlen(magic_version_2_0); + if(length>buf_size) + length=buf_size; + if(!memcmp(magic_version_2_0,buf,length)) + return 2; + return 0; +} + +static int cloop_open(BlockDriverState *bs, const char *filename, int flags) +{ + BDRVCloopState *s = bs->opaque; + uint32_t offsets_size,max_compressed_block_size=1,i; + + s->fd = open(filename, O_RDONLY | O_BINARY); + if (s->fd < 0) + return -errno; + bs->read_only = 1; + + /* read header */ + if(lseek(s->fd,128,SEEK_SET)<0) { +cloop_close: + close(s->fd); + return -1; + } + if(read(s->fd,&s->block_size,4)<4) + goto cloop_close; + s->block_size=be32_to_cpu(s->block_size); + if(read(s->fd,&s->n_blocks,4)<4) + goto cloop_close; + s->n_blocks=be32_to_cpu(s->n_blocks); + + /* read offsets */ + offsets_size=s->n_blocks*sizeof(uint64_t); + s->offsets=(uint64_t*)qemu_malloc(offsets_size); + if(read(s->fd,s->offsets,offsets_size)<offsets_size) + goto cloop_close; + for(i=0;i<s->n_blocks;i++) { + s->offsets[i]=be64_to_cpu(s->offsets[i]); + if(i>0) { + uint32_t size=s->offsets[i]-s->offsets[i-1]; + if(size>max_compressed_block_size) + max_compressed_block_size=size; + } + } + + /* initialize zlib engine */ + s->compressed_block = qemu_malloc(max_compressed_block_size+1); + s->uncompressed_block = qemu_malloc(s->block_size); + if(inflateInit(&s->zstream) != Z_OK) + goto cloop_close; + s->current_block=s->n_blocks; + + s->sectors_per_block = s->block_size/512; + bs->total_sectors = s->n_blocks*s->sectors_per_block; + return 0; +} + +static inline int cloop_read_block(BDRVCloopState *s,int block_num) +{ + if(s->current_block != block_num) { + int ret; + uint32_t bytes = s->offsets[block_num+1]-s->offsets[block_num]; + + lseek(s->fd, s->offsets[block_num], SEEK_SET); + ret = read(s->fd, s->compressed_block, bytes); + if (ret != bytes) + return -1; + + s->zstream.next_in = s->compressed_block; + s->zstream.avail_in = bytes; + s->zstream.next_out = s->uncompressed_block; + s->zstream.avail_out = s->block_size; + 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 != s->block_size) + return -1; + + s->current_block = block_num; + } + return 0; +} + +static int cloop_read(BlockDriverState *bs, int64_t sector_num, + uint8_t *buf, int nb_sectors) +{ + BDRVCloopState *s = bs->opaque; + int i; + + for(i=0;i<nb_sectors;i++) { + uint32_t sector_offset_in_block=((sector_num+i)%s->sectors_per_block), + block_num=(sector_num+i)/s->sectors_per_block; + if(cloop_read_block(s, block_num) != 0) + return -1; + memcpy(buf+i*512,s->uncompressed_block+sector_offset_in_block*512,512); + } + return 0; +} + +static void cloop_close(BlockDriverState *bs) +{ + BDRVCloopState *s = bs->opaque; + close(s->fd); + if(s->n_blocks>0) + free(s->offsets); + free(s->compressed_block); + free(s->uncompressed_block); + inflateEnd(&s->zstream); +} + +static BlockDriver bdrv_cloop = { + .format_name = "cloop", + .instance_size = sizeof(BDRVCloopState), + .bdrv_probe = cloop_probe, + .bdrv_open = cloop_open, + .bdrv_read = cloop_read, + .bdrv_close = cloop_close, +}; + +static void bdrv_cloop_init(void) +{ + bdrv_register(&bdrv_cloop); +} + +block_init(bdrv_cloop_init); |