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_malloc(s->catalog_size * 4);
 109
 110     ret = bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4);
 111     if (ret < 0) {
 112         goto fail;
 113     }
 114
 115     for (i = 0; i < s->catalog_size; i++)
 116         le32_to_cpus(&s->catalog_bitmap[i]);
 117
 118     qemu_co_mutex_init(&s->lock);
 119     return 0;
 120
 121 fail:
 122     g_free(s->catalog_bitmap);
 123     return ret;
 124 }
 125
 126 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 127 {
 128     BDRVParallelsState *s = bs->opaque;
 129     uint32_t index, offset;
 130
 131     index = sector_num / s->tracks;
 132     offset = sector_num % s->tracks;
 133
 134     /* not allocated */
 135     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 136         return -1;
 137     return (uint64_t)(s->catalog_bitmap[index] + offset) * 512;
 138 }
 139
 140 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 141                     uint8_t *buf, int nb_sectors)
 142 {
 143     while (nb_sectors > 0) {
 144         int64_t position = seek_to_sector(bs, sector_num);
 145         if (position >= 0) {
 146             if (bdrv_pread(bs->file, position, buf, 512) != 512)
 147                 return -1;
 148         } else {
 149             memset(buf, 0, 512);
 150         }
 151         nb_sectors--;
 152         sector_num++;
 153         buf += 512;
 154     }
 155     return 0;
 156 }
 157
 158 static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,
 159                                           uint8_t *buf, int nb_sectors)
 160 {
 161     int ret;
 162     BDRVParallelsState *s = bs->opaque;
 163     qemu_co_mutex_lock(&s->lock);
 164     ret = parallels_read(bs, sector_num, buf, nb_sectors);
 165     qemu_co_mutex_unlock(&s->lock);
 166     return ret;
 167 }
 168
 169 static void parallels_close(BlockDriverState *bs)
 170 {
 171     BDRVParallelsState *s = bs->opaque;
 172     g_free(s->catalog_bitmap);
 173 }
 174
 175 static BlockDriver bdrv_parallels = {
 176     .format_name        = "parallels",
 177     .instance_size      = sizeof(BDRVParallelsState),
 178     .bdrv_probe         = parallels_probe,
 179     .bdrv_open          = parallels_open,
 180     .bdrv_read          = parallels_co_read,
 181     .bdrv_close         = parallels_close,
 182 };
 183
 184 static void bdrv_parallels_init(void)
 185 {
 186     bdrv_register(&bdrv_parallels);
 187 }
 188
 189 block_init(bdrv_parallels_init);