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
29 typedef 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
cloop_probe(const uint8_t * buf,int buf_size,const char * filename)40 static 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
cloop_open(BlockDriverState * bs,int flags)53 static 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
98 cloop_close:
99 return -1;
100 }
101
cloop_read_block(BlockDriverState * bs,int block_num)102 static 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
cloop_read(BlockDriverState * bs,int64_t sector_num,uint8_t * buf,int nb_sectors)131 static 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
cloop_close(BlockDriverState * bs)147 static 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
157 static 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
bdrv_cloop_init(void)166 static void bdrv_cloop_init(void)
167 {
168 bdrv_register(&bdrv_cloop);
169 }
170
171 block_init(bdrv_cloop_init);
172