source: trunk/packages/xen-3.1/xen-3.1/tools/ioemu/block-cloop.c @ 34

Last change on this file since 34 was 34, checked in by hartmans, 18 years ago

Add xen and xen-common

File size: 4.8 KB
Line 
1/*
2 * QEMU Block driver for CLOOP images
3 *
4 * Copyright (c) 2004 Johannes E. Schindelin
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24#include "vl.h"
25#include "block_int.h"
26#include <zlib.h>
27
28typedef struct BDRVCloopState {
29    int fd;
30    uint32_t block_size;
31    uint32_t n_blocks;
32    uint64_t* offsets;
33    uint32_t sectors_per_block;
34    uint32_t current_block;
35    uint8_t *compressed_block;
36    uint8_t *uncompressed_block;
37    z_stream zstream;
38} BDRVCloopState;
39
40static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename)
41{
42    const char* magic_version_2_0="#!/bin/sh\n"
43        "#V2.0 Format\n"
44        "modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n";
45    int length=strlen(magic_version_2_0);
46    if(length>buf_size)
47        length=buf_size;
48    if(!memcmp(magic_version_2_0,buf,length))
49        return 2;
50    return 0;
51}
52
53static int cloop_open(BlockDriverState *bs, const char *filename)
54{
55    BDRVCloopState *s = bs->opaque;
56    uint32_t offsets_size,max_compressed_block_size=1,i;
57
58    s->fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
59    if (s->fd < 0)
60        return -1;
61    bs->read_only = 1;
62
63    /* read header */
64    if(lseek(s->fd,128,SEEK_SET)<0) {
65cloop_close:
66        close(s->fd);
67        return -1;
68    }
69    if(read(s->fd,&s->block_size,4)<4)
70        goto cloop_close;
71    s->block_size=be32_to_cpu(s->block_size);
72    if(read(s->fd,&s->n_blocks,4)<4)
73        goto cloop_close;
74    s->n_blocks=be32_to_cpu(s->n_blocks);
75
76    /* read offsets */
77    offsets_size=s->n_blocks*sizeof(uint64_t);
78    if(!(s->offsets=(uint64_t*)malloc(offsets_size)))
79        goto cloop_close;
80    if(read(s->fd,s->offsets,offsets_size)<offsets_size)
81        goto cloop_close;
82    for(i=0;i<s->n_blocks;i++) {
83        s->offsets[i]=be64_to_cpu(s->offsets[i]);
84        if(i>0) {
85            uint32_t size=s->offsets[i]-s->offsets[i-1];
86            if(size>max_compressed_block_size)
87                max_compressed_block_size=size;
88        }
89    }
90
91    /* initialize zlib engine */
92    if(!(s->compressed_block = malloc(max_compressed_block_size+1)))
93        goto cloop_close;
94    if(!(s->uncompressed_block = malloc(s->block_size)))
95        goto cloop_close;
96    if(inflateInit(&s->zstream) != Z_OK)
97        goto cloop_close;
98    s->current_block=s->n_blocks;
99   
100    s->sectors_per_block = s->block_size/512;
101    bs->total_sectors = s->n_blocks*s->sectors_per_block;
102    return 0;
103}
104
105static inline int cloop_read_block(BDRVCloopState *s,int block_num)
106{
107    if(s->current_block != block_num) {
108        int ret;
109        uint32_t bytes = s->offsets[block_num+1]-s->offsets[block_num];
110           
111        lseek(s->fd, s->offsets[block_num], SEEK_SET);
112        ret = read(s->fd, s->compressed_block, bytes);
113        if (ret != bytes) 
114            return -1;
115       
116        s->zstream.next_in = s->compressed_block;
117        s->zstream.avail_in = bytes;
118        s->zstream.next_out = s->uncompressed_block;
119        s->zstream.avail_out = s->block_size;
120        ret = inflateReset(&s->zstream);
121        if(ret != Z_OK)
122            return -1;
123        ret = inflate(&s->zstream, Z_FINISH);
124        if(ret != Z_STREAM_END || s->zstream.total_out != s->block_size)
125            return -1;
126       
127        s->current_block = block_num;
128    }
129    return 0;
130}
131
132static int cloop_read(BlockDriverState *bs, int64_t sector_num, 
133                    uint8_t *buf, int nb_sectors)
134{
135    BDRVCloopState *s = bs->opaque;
136    int i;
137
138    for(i=0;i<nb_sectors;i++) {
139        uint32_t sector_offset_in_block=((sector_num+i)%s->sectors_per_block),
140            block_num=(sector_num+i)/s->sectors_per_block;
141        if(cloop_read_block(s, block_num) != 0)
142            return -1;
143        memcpy(buf+i*512,s->uncompressed_block+sector_offset_in_block*512,512);
144    }
145    return 0;
146}
147
148static void cloop_close(BlockDriverState *bs)
149{
150    BDRVCloopState *s = bs->opaque;
151    close(s->fd);
152    if(s->n_blocks>0)
153        free(s->offsets);
154    free(s->compressed_block);
155    free(s->uncompressed_block);
156    inflateEnd(&s->zstream);
157}
158
159BlockDriver bdrv_cloop = {
160    "cloop",
161    sizeof(BDRVCloopState),
162    cloop_probe,
163    cloop_open,
164    cloop_read,
165    NULL,
166    cloop_close,
167};
168
169
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