block/parallels.c

   1 /*
   2  * Block driver for Parallels disk image format
   3  *
   4  * Copyright (c) 2007 Alex Beregszaszi
   5  *
   6  * This code is based on comparing different disk images created by Parallels.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24  * THE SOFTWARE.
  25  */
  26 #include "qemu-common.h"
  27 #include "block_int.h"
  28 #include "module.h"
  29
  30 /**************************************************************/
  31
  32 #define HEADER_MAGIC "WithoutFreeSpace"
  33 #define HEADER_VERSION 2
  34 #define HEADER_SIZE 64
  35
  36 // always little-endian
  37 struct parallels_header {
  38     char magic[16]; // "WithoutFreeSpace"
  39     uint32_t version;
  40     uint32_t heads;
  41     uint32_t cylinders;
  42     uint32_t tracks;
  43     uint32_t catalog_entries;
  44     uint32_t nb_sectors;
  45     char padding[24];
  46 } __attribute__((packed));
  47
  48 typedef struct BDRVParallelsState {
  49
  50     uint32_t *catalog_bitmap;
  51     int catalog_size;
  52
  53     int tracks;
  54 } BDRVParallelsState;
  55
  56 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
  57 {
  58     const struct parallels_header *ph = (const void *)buf;
  59
  60     if (buf_size < HEADER_SIZE)
  61         return 0;
  62
  63     if (!memcmp(ph->magic, HEADER_MAGIC, 16) &&
  64         (le32_to_cpu(ph->version) == HEADER_VERSION))
  65         return 100;
  66
  67     return 0;
  68 }
  69
  70 static int parallels_open(BlockDriverState *bs, int flags)
  71 {
  72     BDRVParallelsState *s = bs->opaque;
  73     int i;
  74     struct parallels_header ph;
  75
  76     bs->read_only = 1; // no write support yet
  77
  78     if (bdrv_pread(bs->file, 0, &ph, sizeof(ph)) != sizeof(ph))
  79         goto fail;
  80
  81     if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
  82         (le32_to_cpu(ph.version) != HEADER_VERSION)) {
  83         goto fail;
  84     }
  85
  86     bs->total_sectors = le32_to_cpu(ph.nb_sectors);
  87
  88     s->tracks = le32_to_cpu(ph.tracks);
  89
  90     s->catalog_size = le32_to_cpu(ph.catalog_entries);
  91     s->catalog_bitmap = g_malloc(s->catalog_size * 4);
  92     if (bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4) !=
  93         s->catalog_size * 4)
  94         goto fail;
  95     for (i = 0; i < s->catalog_size; i++)
  96         le32_to_cpus(&s->catalog_bitmap[i]);
  97
  98     return 0;
  99 fail:
 100     if (s->catalog_bitmap)
 101         g_free(s->catalog_bitmap);
 102     return -1;
 103 }
 104
 105 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 106 {
 107     BDRVParallelsState *s = bs->opaque;
 108     uint32_t index, offset;
 109
 110     index = sector_num / s->tracks;
 111     offset = sector_num % s->tracks;
 112
 113     /* not allocated */
 114     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 115         return -1;
 116     return (uint64_t)(s->catalog_bitmap[index] + offset) * 512;
 117 }
 118
 119 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 120                     uint8_t *buf, int nb_sectors)
 121 {
 122     while (nb_sectors > 0) {
 123         int64_t position = seek_to_sector(bs, sector_num);
 124         if (position >= 0) {
 125             if (bdrv_pread(bs->file, position, buf, 512) != 512)
 126                 return -1;
 127         } else {
 128             memset(buf, 0, 512);
 129         }
 130         nb_sectors--;
 131         sector_num++;
 132         buf += 512;
 133     }
 134     return 0;
 135 }
 136
 137 static void parallels_close(BlockDriverState *bs)
 138 {
 139     BDRVParallelsState *s = bs->opaque;
 140     g_free(s->catalog_bitmap);
 141 }
 142
 143 static BlockDriver bdrv_parallels = {
 144     .format_name        = "parallels",
 145     .instance_size      = sizeof(BDRVParallelsState),
 146     .bdrv_probe         = parallels_probe,
 147     .bdrv_open          = parallels_open,
 148     .bdrv_read          = parallels_read,
 149     .bdrv_close         = parallels_close,
 150 };
 151
 152 static void bdrv_parallels_init(void)
 153 {
 154     bdrv_register(&bdrv_parallels);
 155 }
 156
 157 block_init(bdrv_parallels_init);