Statistics
| Branch: | Revision:

root / block-dmg.c @ 83f64091

History | View | Annotate | Download (8.1 kB)

1
/*
2
 * QEMU Block driver for DMG 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 "bswap.h"
27
#include <zlib.h>
28

    
29
typedef struct BDRVDMGState {
30
    int fd;
31
    
32
    /* each chunk contains a certain number of sectors,
33
     * offsets[i] is the offset in the .dmg file,
34
     * lengths[i] is the length of the compressed chunk,
35
     * sectors[i] is the sector beginning at offsets[i],
36
     * sectorcounts[i] is the number of sectors in that chunk,
37
     * the sectors array is ordered
38
     * 0<=i<n_chunks */
39

    
40
    uint32_t n_chunks;
41
    uint32_t* types;
42
    uint64_t* offsets;
43
    uint64_t* lengths;
44
    uint64_t* sectors;
45
    uint64_t* sectorcounts;
46
    uint32_t current_chunk;
47
    uint8_t *compressed_chunk;
48
    uint8_t *uncompressed_chunk;
49
    z_stream zstream;
50
} BDRVDMGState;
51

    
52
static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
53
{
54
    int len=strlen(filename);
55
    if(len>4 && !strcmp(filename+len-4,".dmg"))
56
        return 2;
57
    return 0;
58
}
59

    
60
static off_t read_off(int fd)
61
{
62
        uint64_t buffer;
63
        if(read(fd,&buffer,8)<8)
64
                return 0;
65
        return be64_to_cpu(buffer);
66
}
67

    
68
static off_t read_uint32(int fd)
69
{
70
        uint32_t buffer;
71
        if(read(fd,&buffer,4)<4)
72
                return 0;
73
        return be32_to_cpu(buffer);
74
}
75

    
76
static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
77
{
78
    BDRVDMGState *s = bs->opaque;
79
    off_t info_begin,info_end,last_in_offset,last_out_offset;
80
    uint32_t count;
81
    uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
82

    
83
    s->fd = open(filename, O_RDONLY | O_BINARY);
84
    if (s->fd < 0)
85
        return -errno;
86
    bs->read_only = 1;
87
    s->n_chunks = 0;
88
    s->offsets = s->lengths = s->sectors = s->sectorcounts = 0;
89
    
90
    /* read offset of info blocks */
91
    if(lseek(s->fd,-0x1d8,SEEK_END)<0) {
92
dmg_close:
93
        close(s->fd);
94
        /* open raw instead */
95
        bs->drv=&bdrv_raw;
96
        return bs->drv->bdrv_open(bs, filename, flags);
97
    }
98
    info_begin=read_off(s->fd);
99
    if(info_begin==0)
100
        goto dmg_close;
101
    if(lseek(s->fd,info_begin,SEEK_SET)<0)
102
        goto dmg_close;
103
    if(read_uint32(s->fd)!=0x100)
104
        goto dmg_close;
105
    if((count = read_uint32(s->fd))==0)
106
        goto dmg_close;
107
    info_end = info_begin+count;
108
    if(lseek(s->fd,0xf8,SEEK_CUR)<0)
109
        goto dmg_close;
110

    
111
    /* read offsets */
112
    last_in_offset = last_out_offset = 0;
113
    while(lseek(s->fd,0,SEEK_CUR)<info_end) {
114
        uint32_t type;
115

    
116
        count = read_uint32(s->fd);
117
        if(count==0)
118
            goto dmg_close;
119
        type = read_uint32(s->fd);
120
        if(type!=0x6d697368 || count<244)
121
            lseek(s->fd,count-4,SEEK_CUR);
122
        else {
123
            int new_size, chunk_count;
124
            if(lseek(s->fd,200,SEEK_CUR)<0)
125
                goto dmg_close;
126
            chunk_count = (count-204)/40;
127
            new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
128
            s->types = realloc(s->types, new_size/2);
129
            s->offsets = realloc(s->offsets, new_size);
130
            s->lengths = realloc(s->lengths, new_size);
131
            s->sectors = realloc(s->sectors, new_size);
132
            s->sectorcounts = realloc(s->sectorcounts, new_size);
133

    
134
            for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) {
135
                s->types[i] = read_uint32(s->fd);
136
                if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
137
                    if(s->types[i]==0xffffffff) {
138
                        last_in_offset = s->offsets[i-1]+s->lengths[i-1];
139
                        last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1];
140
                    }
141
                    chunk_count--;
142
                    i--;
143
                    if(lseek(s->fd,36,SEEK_CUR)<0)
144
                        goto dmg_close;
145
                    continue;
146
                }
147
                read_uint32(s->fd);
148
                s->sectors[i] = last_out_offset+read_off(s->fd);
149
                s->sectorcounts[i] = read_off(s->fd);
150
                s->offsets[i] = last_in_offset+read_off(s->fd);
151
                s->lengths[i] = read_off(s->fd);
152
                if(s->lengths[i]>max_compressed_size)
153
                    max_compressed_size = s->lengths[i];
154
                if(s->sectorcounts[i]>max_sectors_per_chunk)
155
                    max_sectors_per_chunk = s->sectorcounts[i];
156
            }
157
            s->n_chunks+=chunk_count;
158
        }
159
    }
160

    
161
    /* initialize zlib engine */
162
    if(!(s->compressed_chunk = malloc(max_compressed_size+1)))
163
        goto dmg_close;
164
    if(!(s->uncompressed_chunk = malloc(512*max_sectors_per_chunk)))
165
        goto dmg_close;
166
    if(inflateInit(&s->zstream) != Z_OK)
167
        goto dmg_close;
168

    
169
    s->current_chunk = s->n_chunks;
170
    
171
    return 0;
172
}
173

    
174
static inline int is_sector_in_chunk(BDRVDMGState* s,
175
                uint32_t chunk_num,int sector_num)
176
{
177
    if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num ||
178
            s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num)
179
        return 0;
180
    else
181
        return -1;
182
}
183

    
184
static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
185
{
186
    /* binary search */
187
    uint32_t chunk1=0,chunk2=s->n_chunks,chunk3;
188
    while(chunk1!=chunk2) {
189
        chunk3 = (chunk1+chunk2)/2;
190
        if(s->sectors[chunk3]>sector_num)
191
            chunk2 = chunk3;
192
        else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num)
193
            return chunk3;
194
        else
195
            chunk1 = chunk3;
196
    }
197
    return s->n_chunks; /* error */
198
}
199

    
200
static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
201
{
202
    if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
203
        int ret;
204
        uint32_t chunk = search_chunk(s,sector_num);
205

    
206
        if(chunk>=s->n_chunks)
207
            return -1;
208

    
209
        s->current_chunk = s->n_chunks;
210
        switch(s->types[chunk]) {
211
        case 0x80000005: { /* zlib compressed */
212
            int i;
213

    
214
            ret = lseek(s->fd, s->offsets[chunk], SEEK_SET);
215
            if(ret<0)
216
                return -1;
217

    
218
            /* we need to buffer, because only the chunk as whole can be
219
             * inflated. */
220
            i=0;
221
            do {
222
                ret = read(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i);
223
                if(ret<0 && errno==EINTR)
224
                    ret=0;
225
                i+=ret;
226
            } while(ret>=0 && ret+i<s->lengths[chunk]);
227

    
228
            if (ret != s->lengths[chunk])
229
                return -1;
230
        
231
            s->zstream.next_in = s->compressed_chunk;
232
            s->zstream.avail_in = s->lengths[chunk];
233
            s->zstream.next_out = s->uncompressed_chunk;
234
            s->zstream.avail_out = 512*s->sectorcounts[chunk];
235
            ret = inflateReset(&s->zstream);
236
            if(ret != Z_OK)
237
                return -1;
238
            ret = inflate(&s->zstream, Z_FINISH);
239
            if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk])
240
                return -1;
241
            break; }
242
        case 1: /* copy */
243
            ret = read(s->fd, s->uncompressed_chunk, s->lengths[chunk]);
244
            if (ret != s->lengths[chunk])
245
                return -1;
246
            break;
247
        case 2: /* zero */
248
            memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]);
249
            break;
250
        }
251
        s->current_chunk = chunk;
252
    }
253
    return 0;
254
}
255

    
256
static int dmg_read(BlockDriverState *bs, int64_t sector_num, 
257
                    uint8_t *buf, int nb_sectors)
258
{
259
    BDRVDMGState *s = bs->opaque;
260
    int i;
261

    
262
    for(i=0;i<nb_sectors;i++) {
263
        uint32_t sector_offset_in_chunk;
264
        if(dmg_read_chunk(s, sector_num+i) != 0)
265
            return -1;
266
        sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
267
        memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
268
    }
269
    return 0;
270
}
271

    
272
static void dmg_close(BlockDriverState *bs)
273
{
274
    BDRVDMGState *s = bs->opaque;
275
    close(s->fd);
276
    if(s->n_chunks>0) {
277
        free(s->types);
278
        free(s->offsets);
279
        free(s->lengths);
280
        free(s->sectors);
281
        free(s->sectorcounts);
282
    }
283
    free(s->compressed_chunk);
284
    free(s->uncompressed_chunk);
285
    inflateEnd(&s->zstream);
286
}
287

    
288
BlockDriver bdrv_dmg = {
289
    "dmg",
290
    sizeof(BDRVDMGState),
291
    dmg_probe,
292
    dmg_open,
293
    dmg_read,
294
    NULL,
295
    dmg_close,
296
};
297