block/dmg.c

   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/block_int.h"
  26 #include "qemu/bswap.h"
  27 #include "qemu/module.h"
  28 #include <zlib.h>
  29
  30 typedef struct BDRVDMGState {
  31     CoMutex lock;
  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 int read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result)
  61 {
  62     uint64_t buffer;
  63     int ret;
  64
  65     ret = bdrv_pread(bs->file, offset, &buffer, 8);
  66     if (ret < 0) {
  67         return ret;
  68     }
  69
  70     *result = be64_to_cpu(buffer);
  71     return 0;
  72 }
  73
  74 static int read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result)
  75 {
  76     uint32_t buffer;
  77     int ret;
  78
  79     ret = bdrv_pread(bs->file, offset, &buffer, 4);
  80     if (ret < 0) {
  81         return ret;
  82     }
  83
  84     *result = be32_to_cpu(buffer);
  85     return 0;
  86 }
  87
  88 static int dmg_open(BlockDriverState *bs, int flags)
  89 {
  90     BDRVDMGState *s = bs->opaque;
  91     uint64_t info_begin,info_end,last_in_offset,last_out_offset;
  92     uint32_t count, tmp;
  93     uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
  94     int64_t offset;
  95     int ret;
  96
  97     bs->read_only = 1;
  98     s->n_chunks = 0;
  99     s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
 100
 101     /* read offset of info blocks */
 102     offset = bdrv_getlength(bs->file);
 103     if (offset < 0) {
 104         ret = offset;
 105         goto fail;
 106     }
 107     offset -= 0x1d8;
 108
 109     ret = read_uint64(bs, offset, &info_begin);
 110     if (ret < 0) {
 111         goto fail;
 112     } else if (info_begin == 0) {
 113         ret = -EINVAL;
 114         goto fail;
 115     }
 116
 117     ret = read_uint32(bs, info_begin, &tmp);
 118     if (ret < 0) {
 119         goto fail;
 120     } else if (tmp != 0x100) {
 121         ret = -EINVAL;
 122         goto fail;
 123     }
 124
 125     ret = read_uint32(bs, info_begin + 4, &count);
 126     if (ret < 0) {
 127         goto fail;
 128     } else if (count == 0) {
 129         ret = -EINVAL;
 130         goto fail;
 131     }
 132     info_end = info_begin + count;
 133
 134     offset = info_begin + 0x100;
 135
 136     /* read offsets */
 137     last_in_offset = last_out_offset = 0;
 138     while (offset < info_end) {
 139         uint32_t type;
 140
 141         ret = read_uint32(bs, offset, &count);
 142         if (ret < 0) {
 143             goto fail;
 144         } else if (count == 0) {
 145             ret = -EINVAL;
 146             goto fail;
 147         }
 148         offset += 4;
 149
 150         ret = read_uint32(bs, offset, &type);
 151         if (ret < 0) {
 152             goto fail;
 153         }
 154
 155         if (type == 0x6d697368 && count >= 244) {
 156             int new_size, chunk_count;
 157
 158             offset += 4;
 159             offset += 200;
 160
 161             chunk_count = (count-204)/40;
 162             new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
 163             s->types = g_realloc(s->types, new_size/2);
 164             s->offsets = g_realloc(s->offsets, new_size);
 165             s->lengths = g_realloc(s->lengths, new_size);
 166             s->sectors = g_realloc(s->sectors, new_size);
 167             s->sectorcounts = g_realloc(s->sectorcounts, new_size);
 168
 169             for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) {
 170                 ret = read_uint32(bs, offset, &s->types[i]);
 171                 if (ret < 0) {
 172                     goto fail;
 173                 }
 174                 offset += 4;
 175                 if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
 176                     if(s->types[i]==0xffffffff) {
 177                         last_in_offset = s->offsets[i-1]+s->lengths[i-1];
 178                         last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1];
 179                     }
 180                     chunk_count--;
 181                     i--;
 182                     offset += 36;
 183                     continue;
 184                 }
 185                 offset += 4;
 186
 187                 ret = read_uint64(bs, offset, &s->sectors[i]);
 188                 if (ret < 0) {
 189                     goto fail;
 190                 }
 191                 s->sectors[i] += last_out_offset;
 192                 offset += 8;
 193
 194                 ret = read_uint64(bs, offset, &s->sectorcounts[i]);
 195                 if (ret < 0) {
 196                     goto fail;
 197                 }
 198                 offset += 8;
 199
 200                 ret = read_uint64(bs, offset, &s->offsets[i]);
 201                 if (ret < 0) {
 202                     goto fail;
 203                 }
 204                 s->offsets[i] += last_in_offset;
 205                 offset += 8;
 206
 207                 ret = read_uint64(bs, offset, &s->lengths[i]);
 208                 if (ret < 0) {
 209                     goto fail;
 210                 }
 211                 offset += 8;
 212
 213                 if(s->lengths[i]>max_compressed_size)
 214                     max_compressed_size = s->lengths[i];
 215                 if(s->sectorcounts[i]>max_sectors_per_chunk)
 216                     max_sectors_per_chunk = s->sectorcounts[i];
 217             }
 218             s->n_chunks+=chunk_count;
 219         }
 220     }
 221
 222     /* initialize zlib engine */
 223     s->compressed_chunk = g_malloc(max_compressed_size+1);
 224     s->uncompressed_chunk = g_malloc(512*max_sectors_per_chunk);
 225     if(inflateInit(&s->zstream) != Z_OK) {
 226         ret = -EINVAL;
 227         goto fail;
 228     }
 229
 230     s->current_chunk = s->n_chunks;
 231
 232     qemu_co_mutex_init(&s->lock);
 233     return 0;
 234
 235 fail:
 236     g_free(s->types);
 237     g_free(s->offsets);
 238     g_free(s->lengths);
 239     g_free(s->sectors);
 240     g_free(s->sectorcounts);
 241     g_free(s->compressed_chunk);
 242     g_free(s->uncompressed_chunk);
 243     return ret;
 244 }
 245
 246 static inline int is_sector_in_chunk(BDRVDMGState* s,
 247                 uint32_t chunk_num,int sector_num)
 248 {
 249     if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num ||
 250             s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num)
 251         return 0;
 252     else
 253         return -1;
 254 }
 255
 256 static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
 257 {
 258     /* binary search */
 259     uint32_t chunk1=0,chunk2=s->n_chunks,chunk3;
 260     while(chunk1!=chunk2) {
 261         chunk3 = (chunk1+chunk2)/2;
 262         if(s->sectors[chunk3]>sector_num)
 263             chunk2 = chunk3;
 264         else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num)
 265             return chunk3;
 266         else
 267             chunk1 = chunk3;
 268     }
 269     return s->n_chunks; /* error */
 270 }
 271
 272 static inline int dmg_read_chunk(BlockDriverState *bs, int sector_num)
 273 {
 274     BDRVDMGState *s = bs->opaque;
 275
 276     if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
 277         int ret;
 278         uint32_t chunk = search_chunk(s,sector_num);
 279
 280         if(chunk>=s->n_chunks)
 281             return -1;
 282
 283         s->current_chunk = s->n_chunks;
 284         switch(s->types[chunk]) {
 285         case 0x80000005: { /* zlib compressed */
 286             int i;
 287
 288             /* we need to buffer, because only the chunk as whole can be
 289              * inflated. */
 290             i=0;
 291             do {
 292                 ret = bdrv_pread(bs->file, s->offsets[chunk] + i,
 293                                  s->compressed_chunk+i, s->lengths[chunk]-i);
 294                 if(ret<0 && errno==EINTR)
 295                     ret=0;
 296                 i+=ret;
 297             } while(ret>=0 && ret+i<s->lengths[chunk]);
 298
 299             if (ret != s->lengths[chunk])
 300                 return -1;
 301
 302             s->zstream.next_in = s->compressed_chunk;
 303             s->zstream.avail_in = s->lengths[chunk];
 304             s->zstream.next_out = s->uncompressed_chunk;
 305             s->zstream.avail_out = 512*s->sectorcounts[chunk];
 306             ret = inflateReset(&s->zstream);
 307             if(ret != Z_OK)
 308                 return -1;
 309             ret = inflate(&s->zstream, Z_FINISH);
 310             if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk])
 311                 return -1;
 312             break; }
 313         case 1: /* copy */
 314             ret = bdrv_pread(bs->file, s->offsets[chunk],
 315                              s->uncompressed_chunk, s->lengths[chunk]);
 316             if (ret != s->lengths[chunk])
 317                 return -1;
 318             break;
 319         case 2: /* zero */
 320             memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]);
 321             break;
 322         }
 323         s->current_chunk = chunk;
 324     }
 325     return 0;
 326 }
 327
 328 static int dmg_read(BlockDriverState *bs, int64_t sector_num,
 329                     uint8_t *buf, int nb_sectors)
 330 {
 331     BDRVDMGState *s = bs->opaque;
 332     int i;
 333
 334     for(i=0;i<nb_sectors;i++) {
 335         uint32_t sector_offset_in_chunk;
 336         if(dmg_read_chunk(bs, sector_num+i) != 0)
 337             return -1;
 338         sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
 339         memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
 340     }
 341     return 0;
 342 }
 343
 344 static coroutine_fn int dmg_co_read(BlockDriverState *bs, int64_t sector_num,
 345                                     uint8_t *buf, int nb_sectors)
 346 {
 347     int ret;
 348     BDRVDMGState *s = bs->opaque;
 349     qemu_co_mutex_lock(&s->lock);
 350     ret = dmg_read(bs, sector_num, buf, nb_sectors);
 351     qemu_co_mutex_unlock(&s->lock);
 352     return ret;
 353 }
 354
 355 static void dmg_close(BlockDriverState *bs)
 356 {
 357     BDRVDMGState *s = bs->opaque;
 358
 359     g_free(s->types);
 360     g_free(s->offsets);
 361     g_free(s->lengths);
 362     g_free(s->sectors);
 363     g_free(s->sectorcounts);
 364     g_free(s->compressed_chunk);
 365     g_free(s->uncompressed_chunk);
 366
 367     inflateEnd(&s->zstream);
 368 }
 369
 370 static BlockDriver bdrv_dmg = {
 371     .format_name        = "dmg",
 372     .instance_size      = sizeof(BDRVDMGState),
 373     .bdrv_probe         = dmg_probe,
 374     .bdrv_open          = dmg_open,
 375     .bdrv_read          = dmg_co_read,
 376     .bdrv_close         = dmg_close,
 377 };
 378
 379 static void bdrv_dmg_init(void)
 380 {
 381     bdrv_register(&bdrv_dmg);
 382 }
 383
 384 block_init(bdrv_dmg_init);