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     uint64_t nb_sectors;
  45     uint32_t inuse;
  46     uint32_t data_off;
  47     char padding[12];
  48 } QEMU_PACKED;
  49
  50 typedef struct BDRVParallelsState {
  51     CoMutex lock;
  52
  53     uint32_t *catalog_bitmap;
  54     unsigned int catalog_size;
  55
  56     unsigned int tracks;
  57 } BDRVParallelsState;
  58
  59 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
  60 {
  61     const struct parallels_header *ph = (const void *)buf;
  62
  63     if (buf_size < HEADER_SIZE)
  64         return 0;
  65
  66     if (!memcmp(ph->magic, HEADER_MAGIC, 16) &&
  67         (le32_to_cpu(ph->version) == HEADER_VERSION))
  68         return 100;
  69
  70     return 0;
  71 }
  72
  73 static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
  74                           Error **errp)
  75 {
  76     BDRVParallelsState *s = bs->opaque;
  77     int i;
  78     struct parallels_header ph;
  79     int ret;
  80
  81     bs->read_only = 1; // no write support yet
  82
  83     ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));
  84     if (ret < 0) {
  85         goto fail;
  86     }
  87
  88     if (le32_to_cpu(ph.version) != HEADER_VERSION) {
  89         goto fail_format;
  90     }
  91     if (memcmp(ph.magic, HEADER_MAGIC, 16)) {
  92         goto fail_format;
  93     }
  94
  95     bs->total_sectors = 0xffffffff & le64_to_cpu(ph.nb_sectors);
  96
  97     s->tracks = le32_to_cpu(ph.tracks);
  98     if (s->tracks == 0) {
  99         error_setg(errp, "Invalid image: Zero sectors per track");
 100         ret = -EINVAL;
 101         goto fail;
 102     }
 103
 104     s->catalog_size = le32_to_cpu(ph.catalog_entries);
 105     if (s->catalog_size > INT_MAX / 4) {
 106         error_setg(errp, "Catalog too large");
 107         ret = -EFBIG;
 108         goto fail;
 109     }
 110     s->catalog_bitmap = g_try_malloc(s->catalog_size * 4);
 111     if (s->catalog_size && s->catalog_bitmap == NULL) {
 112         ret = -ENOMEM;
 113         goto fail;
 114     }
 115
 116     ret = bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4);
 117     if (ret < 0) {
 118         goto fail;
 119     }
 120
 121     for (i = 0; i < s->catalog_size; i++)
 122         le32_to_cpus(&s->catalog_bitmap[i]);
 123
 124     qemu_co_mutex_init(&s->lock);
 125     return 0;
 126
 127 fail_format:
 128     error_setg(errp, "Image not in Parallels format");
 129     ret = -EINVAL;
 130 fail:
 131     g_free(s->catalog_bitmap);
 132     return ret;
 133 }
 134
 135 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 136 {
 137     BDRVParallelsState *s = bs->opaque;
 138     uint32_t index, offset;
 139
 140     index = sector_num / s->tracks;
 141     offset = sector_num % s->tracks;
 142
 143     /* not allocated */
 144     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 145         return -1;
 146     return (uint64_t)(s->catalog_bitmap[index] + offset) * 512;
 147 }
 148
 149 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 150                     uint8_t *buf, int nb_sectors)
 151 {
 152     while (nb_sectors > 0) {
 153         int64_t position = seek_to_sector(bs, sector_num);
 154         if (position >= 0) {
 155             if (bdrv_pread(bs->file, position, buf, 512) != 512)
 156                 return -1;
 157         } else {
 158             memset(buf, 0, 512);
 159         }
 160         nb_sectors--;
 161         sector_num++;
 162         buf += 512;
 163     }
 164     return 0;
 165 }
 166
 167 static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,
 168                                           uint8_t *buf, int nb_sectors)
 169 {
 170     int ret;
 171     BDRVParallelsState *s = bs->opaque;
 172     qemu_co_mutex_lock(&s->lock);
 173     ret = parallels_read(bs, sector_num, buf, nb_sectors);
 174     qemu_co_mutex_unlock(&s->lock);
 175     return ret;
 176 }
 177
 178 static void parallels_close(BlockDriverState *bs)
 179 {
 180     BDRVParallelsState *s = bs->opaque;
 181     g_free(s->catalog_bitmap);
 182 }
 183
 184 static BlockDriver bdrv_parallels = {
 185     .format_name        = "parallels",
 186     .instance_size      = sizeof(BDRVParallelsState),
 187     .bdrv_probe         = parallels_probe,
 188     .bdrv_open          = parallels_open,
 189     .bdrv_read          = parallels_co_read,
 190     .bdrv_close         = parallels_close,
 191 };
 192
 193 static void bdrv_parallels_init(void)
 194 {
 195     bdrv_register(&bdrv_parallels);
 196 }
 197
 198 block_init(bdrv_parallels_init);