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     unsigned int catalog_size;
  53
  54     unsigned 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, QDict *options, int flags,
  72                           Error **errp)
  73 {
  74     BDRVParallelsState *s = bs->opaque;
  75     int i;
  76     struct parallels_header ph;
  77     int ret;
  78
  79     bs->read_only = 1; // no write support yet
  80
  81     ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));
  82     if (ret < 0) {
  83         goto fail;
  84     }
  85
  86     if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
  87         (le32_to_cpu(ph.version) != HEADER_VERSION)) {
  88         error_setg(errp, "Image not in Parallels format");
  89         ret = -EINVAL;
  90         goto fail;
  91     }
  92
  93     bs->total_sectors = le32_to_cpu(ph.nb_sectors);
  94
  95     s->tracks = le32_to_cpu(ph.tracks);
  96     if (s->tracks == 0) {
  97         error_setg(errp, "Invalid image: Zero sectors per track");
  98         ret = -EINVAL;
  99         goto fail;
 100     }
 101
 102     s->catalog_size = le32_to_cpu(ph.catalog_entries);
 103     if (s->catalog_size > INT_MAX / 4) {
 104         error_setg(errp, "Catalog too large");
 105         ret = -EFBIG;
 106         goto fail;
 107     }
 108     s->catalog_bitmap = g_try_malloc(s->catalog_size * 4);
 109     if (s->catalog_size && s->catalog_bitmap == NULL) {
 110         ret = -ENOMEM;
 111         goto fail;
 112     }
 113
 114     ret = bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4);
 115     if (ret < 0) {
 116         goto fail;
 117     }
 118
 119     for (i = 0; i < s->catalog_size; i++)
 120         le32_to_cpus(&s->catalog_bitmap[i]);
 121
 122     qemu_co_mutex_init(&s->lock);
 123     return 0;
 124
 125 fail:
 126     g_free(s->catalog_bitmap);
 127     return ret;
 128 }
 129
 130 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 131 {
 132     BDRVParallelsState *s = bs->opaque;
 133     uint32_t index, offset;
 134
 135     index = sector_num / s->tracks;
 136     offset = sector_num % s->tracks;
 137
 138     /* not allocated */
 139     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 140         return -1;
 141     return (uint64_t)(s->catalog_bitmap[index] + offset) * 512;
 142 }
 143
 144 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 145                     uint8_t *buf, int nb_sectors)
 146 {
 147     while (nb_sectors > 0) {
 148         int64_t position = seek_to_sector(bs, sector_num);
 149         if (position >= 0) {
 150             if (bdrv_pread(bs->file, position, buf, 512) != 512)
 151                 return -1;
 152         } else {
 153             memset(buf, 0, 512);
 154         }
 155         nb_sectors--;
 156         sector_num++;
 157         buf += 512;
 158     }
 159     return 0;
 160 }
 161
 162 static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,
 163                                           uint8_t *buf, int nb_sectors)
 164 {
 165     int ret;
 166     BDRVParallelsState *s = bs->opaque;
 167     qemu_co_mutex_lock(&s->lock);
 168     ret = parallels_read(bs, sector_num, buf, nb_sectors);
 169     qemu_co_mutex_unlock(&s->lock);
 170     return ret;
 171 }
 172
 173 static void parallels_close(BlockDriverState *bs)
 174 {
 175     BDRVParallelsState *s = bs->opaque;
 176     g_free(s->catalog_bitmap);
 177 }
 178
 179 static BlockDriver bdrv_parallels = {
 180     .format_name        = "parallels",
 181     .instance_size      = sizeof(BDRVParallelsState),
 182     .bdrv_probe         = parallels_probe,
 183     .bdrv_open          = parallels_open,
 184     .bdrv_read          = parallels_co_read,
 185     .bdrv_close         = parallels_close,
 186 };
 187
 188 static void bdrv_parallels_init(void)
 189 {
 190     bdrv_register(&bdrv_parallels);
 191 }
 192
 193 block_init(bdrv_parallels_init);