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;
  55
  56     if (!filename) {
  57         return 0;
  58     }
  59
  60     len = strlen(filename);
  61     if (len > 4 && !strcmp(filename + len - 4, ".dmg")) {
  62         return 2;
  63     }
  64     return 0;
  65 }
  66
  67 static int read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result)
  68 {
  69     uint64_t buffer;
  70     int ret;
  71
  72     ret = bdrv_pread(bs->file, offset, &buffer, 8);
  73     if (ret < 0) {
  74         return ret;
  75     }
  76
  77     *result = be64_to_cpu(buffer);
  78     return 0;
  79 }
  80
  81 static int read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result)
  82 {
  83     uint32_t buffer;
  84     int ret;
  85
  86     ret = bdrv_pread(bs->file, offset, &buffer, 4);
  87     if (ret < 0) {
  88         return ret;
  89     }
  90
  91     *result = be32_to_cpu(buffer);
  92     return 0;
  93 }
  94
  95 static int dmg_open(BlockDriverState *bs, QDict *options, int flags)
  96 {
  97     BDRVDMGState *s = bs->opaque;
  98     uint64_t info_begin,info_end,last_in_offset,last_out_offset;
  99     uint32_t count, tmp;
 100     uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
 101     int64_t offset;
 102     int ret;
 103
 104     bs->read_only = 1;
 105     s->n_chunks = 0;
 106     s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
 107
 108     /* read offset of info blocks */
 109     offset = bdrv_getlength(bs->file);
 110     if (offset < 0) {
 111         ret = offset;
 112         goto fail;
 113     }
 114     offset -= 0x1d8;
 115
 116     ret = read_uint64(bs, offset, &info_begin);
 117     if (ret < 0) {
 118         goto fail;
 119     } else if (info_begin == 0) {
 120         ret = -EINVAL;
 121         goto fail;
 122     }
 123
 124     ret = read_uint32(bs, info_begin, &tmp);
 125     if (ret < 0) {
 126         goto fail;
 127     } else if (tmp != 0x100) {
 128         ret = -EINVAL;
 129         goto fail;
 130     }
 131
 132     ret = read_uint32(bs, info_begin + 4, &count);
 133     if (ret < 0) {
 134         goto fail;
 135     } else if (count == 0) {
 136         ret = -EINVAL;
 137         goto fail;
 138     }
 139     info_end = info_begin + count;
 140
 141     offset = info_begin + 0x100;
 142
 143     /* read offsets */
 144     last_in_offset = last_out_offset = 0;
 145     while (offset < info_end) {
 146         uint32_t type;
 147
 148         ret = read_uint32(bs, offset, &count);
 149         if (ret < 0) {
 150             goto fail;
 151         } else if (count == 0) {
 152             ret = -EINVAL;
 153             goto fail;
 154         }
 155         offset += 4;
 156
 157         ret = read_uint32(bs, offset, &type);
 158         if (ret < 0) {
 159             goto fail;
 160         }
 161
 162         if (type == 0x6d697368 && count >= 244) {
 163             int new_size, chunk_count;
 164
 165             offset += 4;
 166             offset += 200;
 167
 168             chunk_count = (count-204)/40;
 169             new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
 170             s->types = g_realloc(s->types, new_size/2);
 171             s->offsets = g_realloc(s->offsets, new_size);
 172             s->lengths = g_realloc(s->lengths, new_size);
 173             s->sectors = g_realloc(s->sectors, new_size);
 174             s->sectorcounts = g_realloc(s->sectorcounts, new_size);
 175
 176             for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) {
 177                 ret = read_uint32(bs, offset, &s->types[i]);
 178                 if (ret < 0) {
 179                     goto fail;
 180                 }
 181                 offset += 4;
 182                 if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
 183                     if(s->types[i]==0xffffffff) {
 184                         last_in_offset = s->offsets[i-1]+s->lengths[i-1];
 185                         last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1];
 186                     }
 187                     chunk_count--;
 188                     i--;
 189                     offset += 36;
 190                     continue;
 191                 }
 192                 offset += 4;
 193
 194                 ret = read_uint64(bs, offset, &s->sectors[i]);
 195                 if (ret < 0) {
 196                     goto fail;
 197                 }
 198                 s->sectors[i] += last_out_offset;
 199                 offset += 8;
 200
 201                 ret = read_uint64(bs, offset, &s->sectorcounts[i]);
 202                 if (ret < 0) {
 203                     goto fail;
 204                 }
 205                 offset += 8;
 206
 207                 ret = read_uint64(bs, offset, &s->offsets[i]);
 208                 if (ret < 0) {
 209                     goto fail;
 210                 }
 211                 s->offsets[i] += last_in_offset;
 212                 offset += 8;
 213
 214                 ret = read_uint64(bs, offset, &s->lengths[i]);
 215                 if (ret < 0) {
 216                     goto fail;
 217                 }
 218                 offset += 8;
 219
 220                 if(s->lengths[i]>max_compressed_size)
 221                     max_compressed_size = s->lengths[i];
 222                 if(s->sectorcounts[i]>max_sectors_per_chunk)
 223                     max_sectors_per_chunk = s->sectorcounts[i];
 224             }
 225             s->n_chunks+=chunk_count;
 226         }
 227     }
 228
 229     /* initialize zlib engine */
 230     s->compressed_chunk = g_malloc(max_compressed_size+1);
 231     s->uncompressed_chunk = g_malloc(512*max_sectors_per_chunk);
 232     if(inflateInit(&s->zstream) != Z_OK) {
 233         ret = -EINVAL;
 234         goto fail;
 235     }
 236
 237     s->current_chunk = s->n_chunks;
 238
 239     qemu_co_mutex_init(&s->lock);
 240     return 0;
 241
 242 fail:
 243     g_free(s->types);
 244     g_free(s->offsets);
 245     g_free(s->lengths);
 246     g_free(s->sectors);
 247     g_free(s->sectorcounts);
 248     g_free(s->compressed_chunk);
 249     g_free(s->uncompressed_chunk);
 250     return ret;
 251 }
 252
 253 static inline int is_sector_in_chunk(BDRVDMGState* s,
 254                 uint32_t chunk_num,int sector_num)
 255 {
 256     if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num ||
 257             s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num)
 258         return 0;
 259     else
 260         return -1;
 261 }
 262
 263 static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
 264 {
 265     /* binary search */
 266     uint32_t chunk1=0,chunk2=s->n_chunks,chunk3;
 267     while(chunk1!=chunk2) {
 268         chunk3 = (chunk1+chunk2)/2;
 269         if(s->sectors[chunk3]>sector_num)
 270             chunk2 = chunk3;
 271         else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num)
 272             return chunk3;
 273         else
 274             chunk1 = chunk3;
 275     }
 276     return s->n_chunks; /* error */
 277 }
 278
 279 static inline int dmg_read_chunk(BlockDriverState *bs, int sector_num)
 280 {
 281     BDRVDMGState *s = bs->opaque;
 282
 283     if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
 284         int ret;
 285         uint32_t chunk = search_chunk(s,sector_num);
 286
 287         if(chunk>=s->n_chunks)
 288             return -1;
 289
 290         s->current_chunk = s->n_chunks;
 291         switch(s->types[chunk]) {
 292         case 0x80000005: { /* zlib compressed */
 293             int i;
 294
 295             /* we need to buffer, because only the chunk as whole can be
 296              * inflated. */
 297             i=0;
 298             do {
 299                 ret = bdrv_pread(bs->file, s->offsets[chunk] + i,
 300                                  s->compressed_chunk+i, s->lengths[chunk]-i);
 301                 if(ret<0 && errno==EINTR)
 302                     ret=0;
 303                 i+=ret;
 304             } while(ret>=0 && ret+i<s->lengths[chunk]);
 305
 306             if (ret != s->lengths[chunk])
 307                 return -1;
 308
 309             s->zstream.next_in = s->compressed_chunk;
 310             s->zstream.avail_in = s->lengths[chunk];
 311             s->zstream.next_out = s->uncompressed_chunk;
 312             s->zstream.avail_out = 512*s->sectorcounts[chunk];
 313             ret = inflateReset(&s->zstream);
 314             if(ret != Z_OK)
 315                 return -1;
 316             ret = inflate(&s->zstream, Z_FINISH);
 317             if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk])
 318                 return -1;
 319             break; }
 320         case 1: /* copy */
 321             ret = bdrv_pread(bs->file, s->offsets[chunk],
 322                              s->uncompressed_chunk, s->lengths[chunk]);
 323             if (ret != s->lengths[chunk])
 324                 return -1;
 325             break;
 326         case 2: /* zero */
 327             memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]);
 328             break;
 329         }
 330         s->current_chunk = chunk;
 331     }
 332     return 0;
 333 }
 334
 335 static int dmg_read(BlockDriverState *bs, int64_t sector_num,
 336                     uint8_t *buf, int nb_sectors)
 337 {
 338     BDRVDMGState *s = bs->opaque;
 339     int i;
 340
 341     for(i=0;i<nb_sectors;i++) {
 342         uint32_t sector_offset_in_chunk;
 343         if(dmg_read_chunk(bs, sector_num+i) != 0)
 344             return -1;
 345         sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
 346         memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
 347     }
 348     return 0;
 349 }
 350
 351 static coroutine_fn int dmg_co_read(BlockDriverState *bs, int64_t sector_num,
 352                                     uint8_t *buf, int nb_sectors)
 353 {
 354     int ret;
 355     BDRVDMGState *s = bs->opaque;
 356     qemu_co_mutex_lock(&s->lock);
 357     ret = dmg_read(bs, sector_num, buf, nb_sectors);
 358     qemu_co_mutex_unlock(&s->lock);
 359     return ret;
 360 }
 361
 362 static void dmg_close(BlockDriverState *bs)
 363 {
 364     BDRVDMGState *s = bs->opaque;
 365
 366     g_free(s->types);
 367     g_free(s->offsets);
 368     g_free(s->lengths);
 369     g_free(s->sectors);
 370     g_free(s->sectorcounts);
 371     g_free(s->compressed_chunk);
 372     g_free(s->uncompressed_chunk);
 373
 374     inflateEnd(&s->zstream);
 375 }
 376
 377 static BlockDriver bdrv_dmg = {
 378     .format_name        = "dmg",
 379     .instance_size      = sizeof(BDRVDMGState),
 380     .bdrv_probe         = dmg_probe,
 381     .bdrv_open          = dmg_open,
 382     .bdrv_read          = dmg_co_read,
 383     .bdrv_close         = dmg_close,
 384 };
 385
 386 static void bdrv_dmg_init(void)
 387 {
 388     bdrv_register(&bdrv_dmg);
 389 }
 390
 391 block_init(bdrv_dmg_init);