2 * QEMU Block driver for DMG images
4 * Copyright (c) 2004 Johannes E. Schindelin
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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
24 #include "qemu-common.h"
25 #include "block_int.h"
29 typedef struct BDRVDMGState {
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
45 uint64_t* sectorcounts;
46 uint32_t current_chunk;
47 uint8_t *compressed_chunk;
48 uint8_t *uncompressed_chunk;
52 static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
54 int len=strlen(filename);
55 if(len>4 && !strcmp(filename+len-4,".dmg"))
60 static off_t read_off(int fd)
63 if(read(fd,&buffer,8)<8)
65 return be64_to_cpu(buffer);
68 static off_t read_uint32(int fd)
71 if(read(fd,&buffer,4)<4)
73 return be32_to_cpu(buffer);
76 static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
78 BDRVDMGState *s = bs->opaque;
79 off_t info_begin,info_end,last_in_offset,last_out_offset;
81 uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
83 s->fd = open(filename, O_RDONLY | O_BINARY);
88 s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
90 /* read offset of info blocks */
91 if(lseek(s->fd,-0x1d8,SEEK_END)<0) {
94 /* open raw instead */
96 return bs->drv->bdrv_open(bs, filename, flags);
98 info_begin=read_off(s->fd);
101 if(lseek(s->fd,info_begin,SEEK_SET)<0)
103 if(read_uint32(s->fd)!=0x100)
105 if((count = read_uint32(s->fd))==0)
107 info_end = info_begin+count;
108 if(lseek(s->fd,0xf8,SEEK_CUR)<0)
112 last_in_offset = last_out_offset = 0;
113 while(lseek(s->fd,0,SEEK_CUR)<info_end) {
116 count = read_uint32(s->fd);
119 type = read_uint32(s->fd);
120 if(type!=0x6d697368 || count<244)
121 lseek(s->fd,count-4,SEEK_CUR);
123 int new_size, chunk_count;
124 if(lseek(s->fd,200,SEEK_CUR)<0)
126 chunk_count = (count-204)/40;
127 new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
128 s->types = qemu_realloc(s->types, new_size/2);
129 s->offsets = qemu_realloc(s->offsets, new_size);
130 s->lengths = qemu_realloc(s->lengths, new_size);
131 s->sectors = qemu_realloc(s->sectors, new_size);
132 s->sectorcounts = qemu_realloc(s->sectorcounts, new_size);
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];
143 if(lseek(s->fd,36,SEEK_CUR)<0)
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];
157 s->n_chunks+=chunk_count;
161 /* initialize zlib engine */
162 s->compressed_chunk = qemu_malloc(max_compressed_size+1);
163 s->uncompressed_chunk = qemu_malloc(512*max_sectors_per_chunk);
164 if(inflateInit(&s->zstream) != Z_OK)
167 s->current_chunk = s->n_chunks;
172 static inline int is_sector_in_chunk(BDRVDMGState* s,
173 uint32_t chunk_num,int sector_num)
175 if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num ||
176 s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num)
182 static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
185 uint32_t chunk1=0,chunk2=s->n_chunks,chunk3;
186 while(chunk1!=chunk2) {
187 chunk3 = (chunk1+chunk2)/2;
188 if(s->sectors[chunk3]>sector_num)
190 else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num)
195 return s->n_chunks; /* error */
198 static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
200 if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
202 uint32_t chunk = search_chunk(s,sector_num);
204 if(chunk>=s->n_chunks)
207 s->current_chunk = s->n_chunks;
208 switch(s->types[chunk]) {
209 case 0x80000005: { /* zlib compressed */
212 ret = lseek(s->fd, s->offsets[chunk], SEEK_SET);
216 /* we need to buffer, because only the chunk as whole can be
220 ret = read(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i);
221 if(ret<0 && errno==EINTR)
224 } while(ret>=0 && ret+i<s->lengths[chunk]);
226 if (ret != s->lengths[chunk])
229 s->zstream.next_in = s->compressed_chunk;
230 s->zstream.avail_in = s->lengths[chunk];
231 s->zstream.next_out = s->uncompressed_chunk;
232 s->zstream.avail_out = 512*s->sectorcounts[chunk];
233 ret = inflateReset(&s->zstream);
236 ret = inflate(&s->zstream, Z_FINISH);
237 if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk])
241 ret = read(s->fd, s->uncompressed_chunk, s->lengths[chunk]);
242 if (ret != s->lengths[chunk])
246 memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]);
249 s->current_chunk = chunk;
254 static int dmg_read(BlockDriverState *bs, int64_t sector_num,
255 uint8_t *buf, int nb_sectors)
257 BDRVDMGState *s = bs->opaque;
260 for(i=0;i<nb_sectors;i++) {
261 uint32_t sector_offset_in_chunk;
262 if(dmg_read_chunk(s, sector_num+i) != 0)
264 sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
265 memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
270 static void dmg_close(BlockDriverState *bs)
272 BDRVDMGState *s = bs->opaque;
279 free(s->sectorcounts);
281 free(s->compressed_chunk);
282 free(s->uncompressed_chunk);
283 inflateEnd(&s->zstream);
286 BlockDriver bdrv_dmg = {
288 sizeof(BDRVDMGState),