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     int ret;
  77
  78     bs->read_only = 1; // no write support yet
  79
  80     ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));
  81     if (ret < 0) {
  82         goto fail;
  83     }
  84
  85     if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
  86         (le32_to_cpu(ph.version) != HEADER_VERSION)) {
  87         ret = -EMEDIUMTYPE;
  88         goto fail;
  89     }
  90
  91     bs->total_sectors = le32_to_cpu(ph.nb_sectors);
  92
  93     s->tracks = le32_to_cpu(ph.tracks);
  94
  95     s->catalog_size = le32_to_cpu(ph.catalog_entries);
  96     s->catalog_bitmap = g_malloc(s->catalog_size * 4);
  97
  98     ret = bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4);
  99     if (ret < 0) {
 100         goto fail;
 101     }
 102
 103     for (i = 0; i < s->catalog_size; i++)
 104         le32_to_cpus(&s->catalog_bitmap[i]);
 105
 106     qemu_co_mutex_init(&s->lock);
 107     return 0;
 108
 109 fail:
 110     g_free(s->catalog_bitmap);
 111     return ret;
 112 }
 113
 114 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 115 {
 116     BDRVParallelsState *s = bs->opaque;
 117     uint32_t index, offset;
 118
 119     index = sector_num / s->tracks;
 120     offset = sector_num % s->tracks;
 121
 122     /* not allocated */
 123     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 124         return -1;
 125     return (uint64_t)(s->catalog_bitmap[index] + offset) * 512;
 126 }
 127
 128 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 129                     uint8_t *buf, int nb_sectors)
 130 {
 131     while (nb_sectors > 0) {
 132         int64_t position = seek_to_sector(bs, sector_num);
 133         if (position >= 0) {
 134             if (bdrv_pread(bs->file, position, buf, 512) != 512)
 135                 return -1;
 136         } else {
 137             memset(buf, 0, 512);
 138         }
 139         nb_sectors--;
 140         sector_num++;
 141         buf += 512;
 142     }
 143     return 0;
 144 }
 145
 146 static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,
 147                                           uint8_t *buf, int nb_sectors)
 148 {
 149     int ret;
 150     BDRVParallelsState *s = bs->opaque;
 151     qemu_co_mutex_lock(&s->lock);
 152     ret = parallels_read(bs, sector_num, buf, nb_sectors);
 153     qemu_co_mutex_unlock(&s->lock);
 154     return ret;
 155 }
 156
 157 static void parallels_close(BlockDriverState *bs)
 158 {
 159     BDRVParallelsState *s = bs->opaque;
 160     g_free(s->catalog_bitmap);
 161 }
 162
 163 static BlockDriver bdrv_parallels = {
 164     .format_name        = "parallels",
 165     .instance_size      = sizeof(BDRVParallelsState),
 166     .bdrv_probe         = parallels_probe,
 167     .bdrv_open          = parallels_open,
 168     .bdrv_read          = parallels_co_read,
 169     .bdrv_close         = parallels_close,
 170 };
 171
 172 static void bdrv_parallels_init(void)
 173 {
 174     bdrv_register(&bdrv_parallels);
 175 }
 176
 177 block_init(bdrv_parallels_init);