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