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/block_int.h"
  28 #include "qemu/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 } QEMU_PACKED;
  47
  48 typedef struct BDRVParallelsState {
  49     CoMutex lock;
  50
  51     uint32_t *catalog_bitmap;
  52     int catalog_size;
  53
  54     int tracks;
  55 } BDRVParallelsState;
  56
  57 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
  58 {
  59     const struct parallels_header *ph = (const void *)buf;
  60
  61     if (buf_size < HEADER_SIZE)
  62         return 0;
  63
  64     if (!memcmp(ph->magic, HEADER_MAGIC, 16) &&
  65         (le32_to_cpu(ph->version) == HEADER_VERSION))
  66         return 100;
  67
  68     return 0;
  69 }
  70
  71 static int parallels_open(BlockDriverState *bs, int flags)
  72 {
  73     BDRVParallelsState *s = bs->opaque;
  74     int i;
  75     struct parallels_header ph;
  76
  77     bs->read_only = 1; // no write support yet
  78
  79     if (bdrv_pread(bs->file, 0, &ph, sizeof(ph)) != sizeof(ph))
  80         goto fail;
  81
  82     if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
  83         (le32_to_cpu(ph.version) != HEADER_VERSION)) {
  84         goto fail;
  85     }
  86
  87     bs->total_sectors = le32_to_cpu(ph.nb_sectors);
  88
  89     s->tracks = le32_to_cpu(ph.tracks);
  90
  91     s->catalog_size = le32_to_cpu(ph.catalog_entries);
  92     s->catalog_bitmap = g_malloc(s->catalog_size * 4);
  93     if (bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4) !=
  94         s->catalog_size * 4)
  95         goto fail;
  96     for (i = 0; i < s->catalog_size; i++)
  97         le32_to_cpus(&s->catalog_bitmap[i]);
  98
  99     qemu_co_mutex_init(&s->lock);
 100     return 0;
 101 fail:
 102     if (s->catalog_bitmap)
 103         g_free(s->catalog_bitmap);
 104     return -1;
 105 }
 106
 107 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 108 {
 109     BDRVParallelsState *s = bs->opaque;
 110     uint32_t index, offset;
 111
 112     index = sector_num / s->tracks;
 113     offset = sector_num % s->tracks;
 114
 115     /* not allocated */
 116     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 117         return -1;
 118     return (uint64_t)(s->catalog_bitmap[index] + offset) * 512;
 119 }
 120
 121 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 122                     uint8_t *buf, int nb_sectors)
 123 {
 124     while (nb_sectors > 0) {
 125         int64_t position = seek_to_sector(bs, sector_num);
 126         if (position >= 0) {
 127             if (bdrv_pread(bs->file, position, buf, 512) != 512)
 128                 return -1;
 129         } else {
 130             memset(buf, 0, 512);
 131         }
 132         nb_sectors--;
 133         sector_num++;
 134         buf += 512;
 135     }
 136     return 0;
 137 }
 138
 139 static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,
 140                                           uint8_t *buf, int nb_sectors)
 141 {
 142     int ret;
 143     BDRVParallelsState *s = bs->opaque;
 144     qemu_co_mutex_lock(&s->lock);
 145     ret = parallels_read(bs, sector_num, buf, nb_sectors);
 146     qemu_co_mutex_unlock(&s->lock);
 147     return ret;
 148 }
 149
 150 static void parallels_close(BlockDriverState *bs)
 151 {
 152     BDRVParallelsState *s = bs->opaque;
 153     g_free(s->catalog_bitmap);
 154 }
 155
 156 static BlockDriver bdrv_parallels = {
 157     .format_name        = "parallels",
 158     .instance_size      = sizeof(BDRVParallelsState),
 159     .bdrv_probe         = parallels_probe,
 160     .bdrv_open          = parallels_open,
 161     .bdrv_read          = parallels_co_read,
 162     .bdrv_close         = parallels_close,
 163 };
 164
 165 static void bdrv_parallels_init(void)
 166 {
 167     bdrv_register(&bdrv_parallels);
 168 }
 169
 170 block_init(bdrv_parallels_init);