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 "qemu-common.h"
25#include "block_int.h"
26#include "module.h"
27#include <zlib.h>
28
29typedef struct BDRVCloopState {
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, int flags)
54{
55    BDRVCloopState *s = bs->opaque;
56    uint32_t offsets_size,max_compressed_block_size=1,i;
57
58    bs->read_only = 1;
59
60    /* read header */
61    if (bdrv_pread(bs->file, 128, &s->block_size, 4) < 4) {
62        goto cloop_close;
63    }
64    s->block_size = be32_to_cpu(s->block_size);
65
66    if (bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4) < 4) {
67        goto cloop_close;
68    }
69    s->n_blocks = be32_to_cpu(s->n_blocks);
70
71    /* read offsets */
72    offsets_size = s->n_blocks * sizeof(uint64_t);
73    s->offsets = qemu_malloc(offsets_size);
74    if (bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size) <
75            offsets_size) {
76	goto cloop_close;
77    }
78    for(i=0;i<s->n_blocks;i++) {
79	s->offsets[i]=be64_to_cpu(s->offsets[i]);
80	if(i>0) {
81	    uint32_t size=s->offsets[i]-s->offsets[i-1];
82	    if(size>max_compressed_block_size)
83		max_compressed_block_size=size;
84	}
85    }
86
87    /* initialize zlib engine */
88    s->compressed_block = qemu_malloc(max_compressed_block_size+1);
89    s->uncompressed_block = qemu_malloc(s->block_size);
90    if(inflateInit(&s->zstream) != Z_OK)
91	goto cloop_close;
92    s->current_block=s->n_blocks;
93
94    s->sectors_per_block = s->block_size/512;
95    bs->total_sectors = s->n_blocks*s->sectors_per_block;
96    return 0;
97
98cloop_close:
99    return -1;
100}
101
102static inline int cloop_read_block(BlockDriverState *bs, int block_num)
103{
104    BDRVCloopState *s = bs->opaque;
105
106    if(s->current_block != block_num) {
107	int ret;
108        uint32_t bytes = s->offsets[block_num+1]-s->offsets[block_num];
109
110        ret = bdrv_pread(bs->file, s->offsets[block_num], s->compressed_block,
111                         bytes);
112        if (ret != bytes)
113            return -1;
114
115	s->zstream.next_in = s->compressed_block;
116	s->zstream.avail_in = bytes;
117	s->zstream.next_out = s->uncompressed_block;
118	s->zstream.avail_out = s->block_size;
119	ret = inflateReset(&s->zstream);
120	if(ret != Z_OK)
121	    return -1;
122	ret = inflate(&s->zstream, Z_FINISH);
123	if(ret != Z_STREAM_END || s->zstream.total_out != s->block_size)
124	    return -1;
125
126	s->current_block = block_num;
127    }
128    return 0;
129}
130
131static int cloop_read(BlockDriverState *bs, int64_t sector_num,
132                    uint8_t *buf, int nb_sectors)
133{
134    BDRVCloopState *s = bs->opaque;
135    int i;
136
137    for(i=0;i<nb_sectors;i++) {
138	uint32_t sector_offset_in_block=((sector_num+i)%s->sectors_per_block),
139	    block_num=(sector_num+i)/s->sectors_per_block;
140	if(cloop_read_block(bs, block_num) != 0)
141	    return -1;
142	memcpy(buf+i*512,s->uncompressed_block+sector_offset_in_block*512,512);
143    }
144    return 0;
145}
146
147static void cloop_close(BlockDriverState *bs)
148{
149    BDRVCloopState *s = bs->opaque;
150    if(s->n_blocks>0)
151	free(s->offsets);
152    free(s->compressed_block);
153    free(s->uncompressed_block);
154    inflateEnd(&s->zstream);
155}
156
157static BlockDriver bdrv_cloop = {
158    .format_name	= "cloop",
159    .instance_size	= sizeof(BDRVCloopState),
160    .bdrv_probe		= cloop_probe,
161    .bdrv_open		= cloop_open,
162    .bdrv_read		= cloop_read,
163    .bdrv_close		= cloop_close,
164};
165
166static void bdrv_cloop_init(void)
167{
168    bdrv_register(&bdrv_cloop);
169}
170
171block_init(bdrv_cloop_init);
172