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_MAGIC2 "WithouFreSpacExt"
  34 #define HEADER_VERSION 2
  35 #define HEADER_SIZE 64
  36
  37 // always little-endian
  38 struct parallels_header {
  39     char magic[16]; // "WithoutFreeSpace"
  40     uint32_t version;
  41     uint32_t heads;
  42     uint32_t cylinders;
  43     uint32_t tracks;
  44     uint32_t catalog_entries;
  45     uint64_t nb_sectors;
  46     uint32_t inuse;
  47     uint32_t data_off;
  48     char padding[12];
  49 } QEMU_PACKED;
  50
  51 typedef struct BDRVParallelsState {
  52     CoMutex lock;
  53
  54     uint32_t *catalog_bitmap;
  55     unsigned int catalog_size;
  56
  57     unsigned int tracks;
  58
  59     unsigned int off_multiplier;
  60 } BDRVParallelsState;
  61
  62 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
  63 {
  64     const struct parallels_header *ph = (const void *)buf;
  65
  66     if (buf_size < HEADER_SIZE)
  67         return 0;
  68
  69     if ((!memcmp(ph->magic, HEADER_MAGIC, 16) ||
  70         !memcmp(ph->magic, HEADER_MAGIC2, 16)) &&
  71         (le32_to_cpu(ph->version) == HEADER_VERSION))
  72         return 100;
  73
  74     return 0;
  75 }
  76
  77 static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
  78                           Error **errp)
  79 {
  80     BDRVParallelsState *s = bs->opaque;
  81     int i;
  82     struct parallels_header ph;
  83     int ret;
  84
  85     bs->read_only = 1; // no write support yet
  86
  87     ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));
  88     if (ret < 0) {
  89         goto fail;
  90     }
  91
  92     bs->total_sectors = le64_to_cpu(ph.nb_sectors);
  93
  94     if (le32_to_cpu(ph.version) != HEADER_VERSION) {
  95         goto fail_format;
  96     }
  97     if (!memcmp(ph.magic, HEADER_MAGIC, 16)) {
  98         s->off_multiplier = 1;
  99         bs->total_sectors = 0xffffffff & bs->total_sectors;
 100     } else if (!memcmp(ph.magic, HEADER_MAGIC2, 16)) {
 101         s->off_multiplier = le32_to_cpu(ph.tracks);
 102     } else {
 103         goto fail_format;
 104     }
 105
 106     s->tracks = le32_to_cpu(ph.tracks);
 107     if (s->tracks == 0) {
 108         error_setg(errp, "Invalid image: Zero sectors per track");
 109         ret = -EINVAL;
 110         goto fail;
 111     }
 112     if (s->tracks > INT32_MAX/513) {
 113         error_setg(errp, "Invalid image: Too big cluster");
 114         ret = -EFBIG;
 115         goto fail;
 116     }
 117
 118     s->catalog_size = le32_to_cpu(ph.catalog_entries);
 119     if (s->catalog_size > INT_MAX / 4) {
 120         error_setg(errp, "Catalog too large");
 121         ret = -EFBIG;
 122         goto fail;
 123     }
 124     s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
 125     if (s->catalog_size && s->catalog_bitmap == NULL) {
 126         ret = -ENOMEM;
 127         goto fail;
 128     }
 129
 130     ret = bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4);
 131     if (ret < 0) {
 132         goto fail;
 133     }
 134
 135     for (i = 0; i < s->catalog_size; i++)
 136         le32_to_cpus(&s->catalog_bitmap[i]);
 137
 138     qemu_co_mutex_init(&s->lock);
 139     return 0;
 140
 141 fail_format:
 142     error_setg(errp, "Image not in Parallels format");
 143     ret = -EINVAL;
 144 fail:
 145     g_free(s->catalog_bitmap);
 146     return ret;
 147 }
 148
 149 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 150 {
 151     BDRVParallelsState *s = bs->opaque;
 152     uint32_t index, offset;
 153
 154     index = sector_num / s->tracks;
 155     offset = sector_num % s->tracks;
 156
 157     /* not allocated */
 158     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 159         return -1;
 160     return
 161         ((uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset) * 512;
 162 }
 163
 164 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 165                     uint8_t *buf, int nb_sectors)
 166 {
 167     while (nb_sectors > 0) {
 168         int64_t position = seek_to_sector(bs, sector_num);
 169         if (position >= 0) {
 170             if (bdrv_pread(bs->file, position, buf, 512) != 512)
 171                 return -1;
 172         } else {
 173             memset(buf, 0, 512);
 174         }
 175         nb_sectors--;
 176         sector_num++;
 177         buf += 512;
 178     }
 179     return 0;
 180 }
 181
 182 static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,
 183                                           uint8_t *buf, int nb_sectors)
 184 {
 185     int ret;
 186     BDRVParallelsState *s = bs->opaque;
 187     qemu_co_mutex_lock(&s->lock);
 188     ret = parallels_read(bs, sector_num, buf, nb_sectors);
 189     qemu_co_mutex_unlock(&s->lock);
 190     return ret;
 191 }
 192
 193 static void parallels_close(BlockDriverState *bs)
 194 {
 195     BDRVParallelsState *s = bs->opaque;
 196     g_free(s->catalog_bitmap);
 197 }
 198
 199 static BlockDriver bdrv_parallels = {
 200     .format_name        = "parallels",
 201     .instance_size      = sizeof(BDRVParallelsState),
 202     .bdrv_probe         = parallels_probe,
 203     .bdrv_open          = parallels_open,
 204     .bdrv_read          = parallels_co_read,
 205     .bdrv_close         = parallels_close,
 206 };
 207
 208 static void bdrv_parallels_init(void)
 209 {
 210     bdrv_register(&bdrv_parallels);
 211 }
 212
 213 block_init(bdrv_parallels_init);