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 "qemu-common.h" 25 #include "block_int.h" 26 #include "bswap.h" 27 #include "module.h" 28 #include <zlib.h> 29 30 typedef struct BDRVDMGState { 31 int fd; 32 33 /* each chunk contains a certain number of sectors, 34 * offsets[i] is the offset in the .dmg file, 35 * lengths[i] is the length of the compressed chunk, 36 * sectors[i] is the sector beginning at offsets[i], 37 * sectorcounts[i] is the number of sectors in that chunk, 38 * the sectors array is ordered 39 * 0<=i<n_chunks */ 40 41 uint32_t n_chunks; 42 uint32_t* types; 43 uint64_t* offsets; 44 uint64_t* lengths; 45 uint64_t* sectors; 46 uint64_t* sectorcounts; 47 uint32_t current_chunk; 48 uint8_t *compressed_chunk; 49 uint8_t *uncompressed_chunk; 50 z_stream zstream; 51 } BDRVDMGState; 52 53 static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename) 54 { 55 int len=strlen(filename); 56 if(len>4 && !strcmp(filename+len-4,".dmg")) 57 return 2; 58 return 0; 59 } 60 61 static off_t read_off(int fd) 62 { 63 uint64_t buffer; 64 if(read(fd,&buffer,8)<8) 65 return 0; 66 return be64_to_cpu(buffer); 67 } 68 69 static off_t read_uint32(int fd) 70 { 71 uint32_t buffer; 72 if(read(fd,&buffer,4)<4) 73 return 0; 74 return be32_to_cpu(buffer); 75 } 76 77 static int dmg_open(BlockDriverState *bs, const char *filename, int flags) 78 { 79 BDRVDMGState *s = bs->opaque; 80 off_t info_begin,info_end,last_in_offset,last_out_offset; 81 uint32_t count; 82 uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i; 83 84 s->fd = open(filename, O_RDONLY | O_BINARY); 85 if (s->fd < 0) 86 return -errno; 87 bs->read_only = 1; 88 s->n_chunks = 0; 89 s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL; 90 91 /* read offset of info blocks */ 92 if(lseek(s->fd,-0x1d8,SEEK_END)<0) { 93 dmg_close: 94 close(s->fd); 95 /* open raw instead */ 96 bs->drv=bdrv_find_format("raw"); 97 return bs->drv->bdrv_open(bs, filename, flags); 98 } 99 info_begin=read_off(s->fd); 100 if(info_begin==0) 101 goto dmg_close; 102 if(lseek(s->fd,info_begin,SEEK_SET)<0) 103 goto dmg_close; 104 if(read_uint32(s->fd)!=0x100) 105 goto dmg_close; 106 if((count = read_uint32(s->fd))==0) 107 goto dmg_close; 108 info_end = info_begin+count; 109 if(lseek(s->fd,0xf8,SEEK_CUR)<0) 110 goto dmg_close; 111 112 /* read offsets */ 113 last_in_offset = last_out_offset = 0; 114 while(lseek(s->fd,0,SEEK_CUR)<info_end) { 115 uint32_t type; 116 117 count = read_uint32(s->fd); 118 if(count==0) 119 goto dmg_close; 120 type = read_uint32(s->fd); 121 if(type!=0x6d697368 || count<244) 122 lseek(s->fd,count-4,SEEK_CUR); 123 else { 124 int new_size, chunk_count; 125 if(lseek(s->fd,200,SEEK_CUR)<0) 126 goto dmg_close; 127 chunk_count = (count-204)/40; 128 new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); 129 s->types = qemu_realloc(s->types, new_size/2); 130 s->offsets = qemu_realloc(s->offsets, new_size); 131 s->lengths = qemu_realloc(s->lengths, new_size); 132 s->sectors = qemu_realloc(s->sectors, new_size); 133 s->sectorcounts = qemu_realloc(s->sectorcounts, new_size); 134 135 for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) { 136 s->types[i] = read_uint32(s->fd); 137 if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) { 138 if(s->types[i]==0xffffffff) { 139 last_in_offset = s->offsets[i-1]+s->lengths[i-1]; 140 last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1]; 141 } 142 chunk_count--; 143 i--; 144 if(lseek(s->fd,36,SEEK_CUR)<0) 145 goto dmg_close; 146 continue; 147 } 148 read_uint32(s->fd); 149 s->sectors[i] = last_out_offset+read_off(s->fd); 150 s->sectorcounts[i] = read_off(s->fd); 151 s->offsets[i] = last_in_offset+read_off(s->fd); 152 s->lengths[i] = read_off(s->fd); 153 if(s->lengths[i]>max_compressed_size) 154 max_compressed_size = s->lengths[i]; 155 if(s->sectorcounts[i]>max_sectors_per_chunk) 156 max_sectors_per_chunk = s->sectorcounts[i]; 157 } 158 s->n_chunks+=chunk_count; 159 } 160 } 161 162 /* initialize zlib engine */ 163 s->compressed_chunk = qemu_malloc(max_compressed_size+1); 164 s->uncompressed_chunk = qemu_malloc(512*max_sectors_per_chunk); 165 if(inflateInit(&s->zstream) != Z_OK) 166 goto dmg_close; 167 168 s->current_chunk = s->n_chunks; 169 170 return 0; 171 } 172 173 static inline int is_sector_in_chunk(BDRVDMGState* s, 174 uint32_t chunk_num,int sector_num) 175 { 176 if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num || 177 s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num) 178 return 0; 179 else 180 return -1; 181 } 182 183 static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num) 184 { 185 /* binary search */ 186 uint32_t chunk1=0,chunk2=s->n_chunks,chunk3; 187 while(chunk1!=chunk2) { 188 chunk3 = (chunk1+chunk2)/2; 189 if(s->sectors[chunk3]>sector_num) 190 chunk2 = chunk3; 191 else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num) 192 return chunk3; 193 else 194 chunk1 = chunk3; 195 } 196 return s->n_chunks; /* error */ 197 } 198 199 static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num) 200 { 201 if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) { 202 int ret; 203 uint32_t chunk = search_chunk(s,sector_num); 204 205 if(chunk>=s->n_chunks) 206 return -1; 207 208 s->current_chunk = s->n_chunks; 209 switch(s->types[chunk]) { 210 case 0x80000005: { /* zlib compressed */ 211 int i; 212 213 ret = lseek(s->fd, s->offsets[chunk], SEEK_SET); 214 if(ret<0) 215 return -1; 216 217 /* we need to buffer, because only the chunk as whole can be 218 * inflated. */ 219 i=0; 220 do { 221 ret = read(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i); 222 if(ret<0 && errno==EINTR) 223 ret=0; 224 i+=ret; 225 } while(ret>=0 && ret+i<s->lengths[chunk]); 226 227 if (ret != s->lengths[chunk]) 228 return -1; 229 230 s->zstream.next_in = s->compressed_chunk; 231 s->zstream.avail_in = s->lengths[chunk]; 232 s->zstream.next_out = s->uncompressed_chunk; 233 s->zstream.avail_out = 512*s->sectorcounts[chunk]; 234 ret = inflateReset(&s->zstream); 235 if(ret != Z_OK) 236 return -1; 237 ret = inflate(&s->zstream, Z_FINISH); 238 if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk]) 239 return -1; 240 break; } 241 case 1: /* copy */ 242 ret = read(s->fd, s->uncompressed_chunk, s->lengths[chunk]); 243 if (ret != s->lengths[chunk]) 244 return -1; 245 break; 246 case 2: /* zero */ 247 memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]); 248 break; 249 } 250 s->current_chunk = chunk; 251 } 252 return 0; 253 } 254 255 static int dmg_read(BlockDriverState *bs, int64_t sector_num, 256 uint8_t *buf, int nb_sectors) 257 { 258 BDRVDMGState *s = bs->opaque; 259 int i; 260 261 for(i=0;i<nb_sectors;i++) { 262 uint32_t sector_offset_in_chunk; 263 if(dmg_read_chunk(s, sector_num+i) != 0) 264 return -1; 265 sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk]; 266 memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512); 267 } 268 return 0; 269 } 270 271 static void dmg_close(BlockDriverState *bs) 272 { 273 BDRVDMGState *s = bs->opaque; 274 close(s->fd); 275 if(s->n_chunks>0) { 276 free(s->types); 277 free(s->offsets); 278 free(s->lengths); 279 free(s->sectors); 280 free(s->sectorcounts); 281 } 282 free(s->compressed_chunk); 283 free(s->uncompressed_chunk); 284 inflateEnd(&s->zstream); 285 } 286 287 static BlockDriver bdrv_dmg = { 288 .format_name = "dmg", 289 .instance_size = sizeof(BDRVDMGState), 290 .bdrv_probe = dmg_probe, 291 .bdrv_open = dmg_open, 292 .bdrv_read = dmg_read, 293 .bdrv_close = dmg_close, 294 }; 295 296 static void bdrv_dmg_init(void) 297 { 298 bdrv_register(&bdrv_dmg); 299 } 300 301 block_init(bdrv_dmg_init); 302
