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 int fd;
31 uint32_t block_size;
32 uint32_t n_blocks;
33 uint64_t* offsets;
34 uint32_t sectors_per_block;
35 uint32_t current_block;
36 uint8_t *compressed_block;
37 uint8_t *uncompressed_block;
38 z_stream zstream;
39 } BDRVCloopState;
40
cloop_probe(const uint8_t * buf,int buf_size,const char * filename)41 static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename)
42 {
43 const char* magic_version_2_0="#!/bin/sh\n"
44 "#V2.0 Format\n"
45 "modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n";
46 int length=strlen(magic_version_2_0);
47 if(length>buf_size)
48 length=buf_size;
49 if(!memcmp(magic_version_2_0,buf,length))
50 return 2;
51 return 0;
52 }
53
cloop_open(BlockDriverState * bs,const char * filename,int flags)54 static int cloop_open(BlockDriverState *bs, const char *filename, int flags)
55 {
56 BDRVCloopState *s = bs->opaque;
57 uint32_t offsets_size,max_compressed_block_size=1,i;
58
59 s->fd = open(filename, O_RDONLY | O_BINARY);
60 if (s->fd < 0)
61 return -errno;
62 bs->read_only = 1;
63
64 /* read header */
65 if(lseek(s->fd,128,SEEK_SET)<0) {
66 cloop_close:
67 close(s->fd);
68 return -1;
69 }
70 if(read(s->fd,&s->block_size,4)<4)
71 goto cloop_close;
72 s->block_size=be32_to_cpu(s->block_size);
73 if(read(s->fd,&s->n_blocks,4)<4)
74 goto cloop_close;
75 s->n_blocks=be32_to_cpu(s->n_blocks);
76
77 /* read offsets */
78 offsets_size=s->n_blocks*sizeof(uint64_t);
79 s->offsets=(uint64_t*)qemu_malloc(offsets_size);
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 s->compressed_block = qemu_malloc(max_compressed_block_size+1);
93 s->uncompressed_block = qemu_malloc(s->block_size);
94 if(inflateInit(&s->zstream) != Z_OK)
95 goto cloop_close;
96 s->current_block=s->n_blocks;
97
98 s->sectors_per_block = s->block_size/512;
99 bs->total_sectors = s->n_blocks*s->sectors_per_block;
100 return 0;
101 }
102
cloop_read_block(BDRVCloopState * s,int block_num)103 static inline int cloop_read_block(BDRVCloopState *s,int block_num)
104 {
105 if(s->current_block != block_num) {
106 int ret;
107 uint32_t bytes = s->offsets[block_num+1]-s->offsets[block_num];
108
109 lseek(s->fd, s->offsets[block_num], SEEK_SET);
110 ret = read(s->fd, s->compressed_block, bytes);
111 if (ret != bytes)
112 return -1;
113
114 s->zstream.next_in = s->compressed_block;
115 s->zstream.avail_in = bytes;
116 s->zstream.next_out = s->uncompressed_block;
117 s->zstream.avail_out = s->block_size;
118 ret = inflateReset(&s->zstream);
119 if(ret != Z_OK)
120 return -1;
121 ret = inflate(&s->zstream, Z_FINISH);
122 if(ret != Z_STREAM_END || s->zstream.total_out != s->block_size)
123 return -1;
124
125 s->current_block = block_num;
126 }
127 return 0;
128 }
129
cloop_read(BlockDriverState * bs,int64_t sector_num,uint8_t * buf,int nb_sectors)130 static int cloop_read(BlockDriverState *bs, int64_t sector_num,
131 uint8_t *buf, int nb_sectors)
132 {
133 BDRVCloopState *s = bs->opaque;
134 int i;
135
136 for(i=0;i<nb_sectors;i++) {
137 uint32_t sector_offset_in_block=((sector_num+i)%s->sectors_per_block),
138 block_num=(sector_num+i)/s->sectors_per_block;
139 if(cloop_read_block(s, block_num) != 0)
140 return -1;
141 memcpy(buf+i*512,s->uncompressed_block+sector_offset_in_block*512,512);
142 }
143 return 0;
144 }
145
cloop_close(BlockDriverState * bs)146 static void cloop_close(BlockDriverState *bs)
147 {
148 BDRVCloopState *s = bs->opaque;
149 close(s->fd);
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