aboutsummaryrefslogtreecommitdiff
path: root/block/dmg.c
blob: d5e9b1ff0163fb80b4830f5c724b11335ce29149 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
/*
 * QEMU Block driver for DMG images
 *
 * Copyright (c) 2004 Johannes E. Schindelin
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "qemu-common.h"
#include "block/block_int.h"
#include "qemu/bswap.h"
#include "qemu/module.h"
#include <zlib.h>

typedef struct BDRVDMGState {
    CoMutex lock;
    /* each chunk contains a certain number of sectors,
     * offsets[i] is the offset in the .dmg file,
     * lengths[i] is the length of the compressed chunk,
     * sectors[i] is the sector beginning at offsets[i],
     * sectorcounts[i] is the number of sectors in that chunk,
     * the sectors array is ordered
     * 0<=i<n_chunks */

    uint32_t n_chunks;
    uint32_t* types;
    uint64_t* offsets;
    uint64_t* lengths;
    uint64_t* sectors;
    uint64_t* sectorcounts;
    uint32_t current_chunk;
    uint8_t *compressed_chunk;
    uint8_t *uncompressed_chunk;
    z_stream zstream;
} BDRVDMGState;

static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
{
    int len;

    if (!filename) {
        return 0;
    }

    len = strlen(filename);
    if (len > 4 && !strcmp(filename + len - 4, ".dmg")) {
        return 2;
    }
    return 0;
}

static int read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result)
{
    uint64_t buffer;
    int ret;

    ret = bdrv_pread(bs->file, offset, &buffer, 8);
    if (ret < 0) {
        return ret;
    }

    *result = be64_to_cpu(buffer);
    return 0;
}

static int read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result)
{
    uint32_t buffer;
    int ret;

    ret = bdrv_pread(bs->file, offset, &buffer, 4);
    if (ret < 0) {
        return ret;
    }

    *result = be32_to_cpu(buffer);
    return 0;
}

static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
                    Error **errp)
{
    BDRVDMGState *s = bs->opaque;
    uint64_t info_begin,info_end,last_in_offset,last_out_offset;
    uint32_t count, tmp;
    uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
    int64_t offset;
    int ret;

    bs->read_only = 1;
    s->n_chunks = 0;
    s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;

    /* read offset of info blocks */
    offset = bdrv_getlength(bs->file);
    if (offset < 0) {
        ret = offset;
        goto fail;
    }
    offset -= 0x1d8;

    ret = read_uint64(bs, offset, &info_begin);
    if (ret < 0) {
        goto fail;
    } else if (info_begin == 0) {
        ret = -EINVAL;
        goto fail;
    }

    ret = read_uint32(bs, info_begin, &tmp);
    if (ret < 0) {
        goto fail;
    } else if (tmp != 0x100) {
        ret = -EINVAL;
        goto fail;
    }

    ret = read_uint32(bs, info_begin + 4, &count);
    if (ret < 0) {
        goto fail;
    } else if (count == 0) {
        ret = -EINVAL;
        goto fail;
    }
    info_end = info_begin + count;

    offset = info_begin + 0x100;

    /* read offsets */
    last_in_offset = last_out_offset = 0;
    while (offset < info_end) {
        uint32_t type;

        ret = read_uint32(bs, offset, &count);
        if (ret < 0) {
            goto fail;
        } else if (count == 0) {
            ret = -EINVAL;
            goto fail;
        }
        offset += 4;

        ret = read_uint32(bs, offset, &type);
        if (ret < 0) {
            goto fail;
        }

	if (type == 0x6d697368 && count >= 244) {
	    int new_size, chunk_count;

            offset += 4;
            offset += 200;

	    chunk_count = (count-204)/40;
	    new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
	    s->types = g_realloc(s->types, new_size/2);
	    s->offsets = g_realloc(s->offsets, new_size);
	    s->lengths = g_realloc(s->lengths, new_size);
	    s->sectors = g_realloc(s->sectors, new_size);
	    s->sectorcounts = g_realloc(s->sectorcounts, new_size);

            for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) {
                ret = read_uint32(bs, offset, &s->types[i]);
                if (ret < 0) {
                    goto fail;
                }
		offset += 4;
		if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
		    if(s->types[i]==0xffffffff) {
			last_in_offset = s->offsets[i-1]+s->lengths[i-1];
			last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1];
		    }
		    chunk_count--;
		    i--;
		    offset += 36;
		    continue;
		}
		offset += 4;

                ret = read_uint64(bs, offset, &s->sectors[i]);
                if (ret < 0) {
                    goto fail;
                }
                s->sectors[i] += last_out_offset;
                offset += 8;

                ret = read_uint64(bs, offset, &s->sectorcounts[i]);
                if (ret < 0) {
                    goto fail;
                }
                offset += 8;

                ret = read_uint64(bs, offset, &s->offsets[i]);
                if (ret < 0) {
                    goto fail;
                }
                s->offsets[i] += last_in_offset;
                offset += 8;

                ret = read_uint64(bs, offset, &s->lengths[i]);
                if (ret < 0) {
                    goto fail;
                }
                offset += 8;

		if(s->lengths[i]>max_compressed_size)
		    max_compressed_size = s->lengths[i];
		if(s->sectorcounts[i]>max_sectors_per_chunk)
		    max_sectors_per_chunk = s->sectorcounts[i];
	    }
	    s->n_chunks+=chunk_count;
	}
    }

    /* initialize zlib engine */
    s->compressed_chunk = g_malloc(max_compressed_size+1);
    s->uncompressed_chunk = g_malloc(512*max_sectors_per_chunk);
    if(inflateInit(&s->zstream) != Z_OK) {
        ret = -EINVAL;
        goto fail;
    }

    s->current_chunk = s->n_chunks;

    qemu_co_mutex_init(&s->lock);
    return 0;

fail:
    g_free(s->types);
    g_free(s->offsets);
    g_free(s->lengths);
    g_free(s->sectors);
    g_free(s->sectorcounts);
    g_free(s->compressed_chunk);
    g_free(s->uncompressed_chunk);
    return ret;
}

static inline int is_sector_in_chunk(BDRVDMGState* s,
		uint32_t chunk_num,int sector_num)
{
    if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num ||
	    s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num)
	return 0;
    else
	return -1;
}

static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
{
    /* binary search */
    uint32_t chunk1=0,chunk2=s->n_chunks,chunk3;
    while(chunk1!=chunk2) {
	chunk3 = (chunk1+chunk2)/2;
	if(s->sectors[chunk3]>sector_num)
	    chunk2 = chunk3;
	else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num)
	    return chunk3;
	else
	    chunk1 = chunk3;
    }
    return s->n_chunks; /* error */
}

static inline int dmg_read_chunk(BlockDriverState *bs, int sector_num)
{
    BDRVDMGState *s = bs->opaque;

    if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
	int ret;
	uint32_t chunk = search_chunk(s,sector_num);

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

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

	    /* we need to buffer, because only the chunk as whole can be
	     * inflated. */
	    i=0;
	    do {
                ret = bdrv_pread(bs->file, s->offsets[chunk] + i,
                                 s->compressed_chunk+i, s->lengths[chunk]-i);
		if(ret<0 && errno==EINTR)
		    ret=0;
		i+=ret;
	    } while(ret>=0 && ret+i<s->lengths[chunk]);

	    if (ret != s->lengths[chunk])
		return -1;

	    s->zstream.next_in = s->compressed_chunk;
	    s->zstream.avail_in = s->lengths[chunk];
	    s->zstream.next_out = s->uncompressed_chunk;
	    s->zstream.avail_out = 512*s->sectorcounts[chunk];
	    ret = inflateReset(&s->zstream);
	    if(ret != Z_OK)
		return -1;
	    ret = inflate(&s->zstream, Z_FINISH);
	    if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk])
		return -1;
	    break; }
	case 1: /* copy */
	    ret = bdrv_pread(bs->file, s->offsets[chunk],
                             s->uncompressed_chunk, s->lengths[chunk]);
	    if (ret != s->lengths[chunk])
		return -1;
	    break;
	case 2: /* zero */
	    memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]);
	    break;
	}
	s->current_chunk = chunk;
    }
    return 0;
}

static int dmg_read(BlockDriverState *bs, int64_t sector_num,
                    uint8_t *buf, int nb_sectors)
{
    BDRVDMGState *s = bs->opaque;
    int i;

    for(i=0;i<nb_sectors;i++) {
	uint32_t sector_offset_in_chunk;
	if(dmg_read_chunk(bs, sector_num+i) != 0)
	    return -1;
	sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
	memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
    }
    return 0;
}

static coroutine_fn int dmg_co_read(BlockDriverState *bs, int64_t sector_num,
                                    uint8_t *buf, int nb_sectors)
{
    int ret;
    BDRVDMGState *s = bs->opaque;
    qemu_co_mutex_lock(&s->lock);
    ret = dmg_read(bs, sector_num, buf, nb_sectors);
    qemu_co_mutex_unlock(&s->lock);
    return ret;
}

static void dmg_close(BlockDriverState *bs)
{
    BDRVDMGState *s = bs->opaque;

    g_free(s->types);
    g_free(s->offsets);
    g_free(s->lengths);
    g_free(s->sectors);
    g_free(s->sectorcounts);
    g_free(s->compressed_chunk);
    g_free(s->uncompressed_chunk);

    inflateEnd(&s->zstream);
}

static BlockDriver bdrv_dmg = {
    .format_name	= "dmg",
    .instance_size	= sizeof(BDRVDMGState),
    .bdrv_probe		= dmg_probe,
    .bdrv_open		= dmg_open,
    .bdrv_read          = dmg_co_read,
    .bdrv_close		= dmg_close,
};

static void bdrv_dmg_init(void)
{
    bdrv_register(&bdrv_dmg);
}

block_init(bdrv_dmg_init);