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
  36 // always little-endian
  37 typedef struct ParallelsHeader {
  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 ParallelsHeader;
  49
  50 typedef struct BDRVParallelsState {
  51     /** Locking is conservative, the lock protects
  52      *   - image file extending (truncate, fallocate)
  53      *   - any access to block allocation table
  54      */
  55     CoMutex lock;
  56
  57     uint32_t *catalog_bitmap;
  58     unsigned int catalog_size;
  59
  60     unsigned int tracks;
  61
  62     unsigned int off_multiplier;
  63 } BDRVParallelsState;
  64
  65 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
  66 {
  67     const ParallelsHeader *ph = (const void *)buf;
  68
  69     if (buf_size < sizeof(ParallelsHeader))
  70         return 0;
  71
  72     if ((!memcmp(ph->magic, HEADER_MAGIC, 16) ||
  73         !memcmp(ph->magic, HEADER_MAGIC2, 16)) &&
  74         (le32_to_cpu(ph->version) == HEADER_VERSION))
  75         return 100;
  76
  77     return 0;
  78 }
  79
  80 static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
  81                           Error **errp)
  82 {
  83     BDRVParallelsState *s = bs->opaque;
  84     int i;
  85     ParallelsHeader ph;
  86     int ret;
  87
  88     bs->read_only = 1; // no write support yet
  89
  90     ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));
  91     if (ret < 0) {
  92         goto fail;
  93     }
  94
  95     bs->total_sectors = le64_to_cpu(ph.nb_sectors);
  96
  97     if (le32_to_cpu(ph.version) != HEADER_VERSION) {
  98         goto fail_format;
  99     }
 100     if (!memcmp(ph.magic, HEADER_MAGIC, 16)) {
 101         s->off_multiplier = 1;
 102         bs->total_sectors = 0xffffffff & bs->total_sectors;
 103     } else if (!memcmp(ph.magic, HEADER_MAGIC2, 16)) {
 104         s->off_multiplier = le32_to_cpu(ph.tracks);
 105     } else {
 106         goto fail_format;
 107     }
 108
 109     s->tracks = le32_to_cpu(ph.tracks);
 110     if (s->tracks == 0) {
 111         error_setg(errp, "Invalid image: Zero sectors per track");
 112         ret = -EINVAL;
 113         goto fail;
 114     }
 115     if (s->tracks > INT32_MAX/513) {
 116         error_setg(errp, "Invalid image: Too big cluster");
 117         ret = -EFBIG;
 118         goto fail;
 119     }
 120
 121     s->catalog_size = le32_to_cpu(ph.catalog_entries);
 122     if (s->catalog_size > INT_MAX / sizeof(uint32_t)) {
 123         error_setg(errp, "Catalog too large");
 124         ret = -EFBIG;
 125         goto fail;
 126     }
 127     s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
 128     if (s->catalog_size && s->catalog_bitmap == NULL) {
 129         ret = -ENOMEM;
 130         goto fail;
 131     }
 132
 133     ret = bdrv_pread(bs->file, sizeof(ParallelsHeader),
 134                      s->catalog_bitmap, s->catalog_size * sizeof(uint32_t));
 135     if (ret < 0) {
 136         goto fail;
 137     }
 138
 139     for (i = 0; i < s->catalog_size; i++)
 140         le32_to_cpus(&s->catalog_bitmap[i]);
 141
 142     qemu_co_mutex_init(&s->lock);
 143     return 0;
 144
 145 fail_format:
 146     error_setg(errp, "Image not in Parallels format");
 147     ret = -EINVAL;
 148 fail:
 149     g_free(s->catalog_bitmap);
 150     return ret;
 151 }
 152
 153 static int64_t seek_to_sector(BDRVParallelsState *s, int64_t sector_num)
 154 {
 155     uint32_t index, offset;
 156
 157     index = sector_num / s->tracks;
 158     offset = sector_num % s->tracks;
 159
 160     /* not allocated */
 161     if ((index >= s->catalog_size) || (s->catalog_bitmap[index] == 0))
 162         return -1;
 163     return (uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset;
 164 }
 165
 166 static int cluster_remainder(BDRVParallelsState *s, int64_t sector_num,
 167         int nb_sectors)
 168 {
 169     int ret = s->tracks - sector_num % s->tracks;
 170     return MIN(nb_sectors, ret);
 171 }
 172
 173 static int64_t coroutine_fn parallels_co_get_block_status(BlockDriverState *bs,
 174         int64_t sector_num, int nb_sectors, int *pnum)
 175 {
 176     BDRVParallelsState *s = bs->opaque;
 177     int64_t offset;
 178
 179     qemu_co_mutex_lock(&s->lock);
 180     offset = seek_to_sector(s, sector_num);
 181     qemu_co_mutex_unlock(&s->lock);
 182
 183     *pnum = cluster_remainder(s, sector_num, nb_sectors);
 184
 185     if (offset < 0) {
 186         return 0;
 187     }
 188
 189     return (offset << BDRV_SECTOR_BITS) |
 190         BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
 191 }
 192
 193 static coroutine_fn int parallels_co_readv(BlockDriverState *bs,
 194         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
 195 {
 196     BDRVParallelsState *s = bs->opaque;
 197     uint64_t bytes_done = 0;
 198     QEMUIOVector hd_qiov;
 199     int ret = 0;
 200
 201     qemu_iovec_init(&hd_qiov, qiov->niov);
 202
 203     while (nb_sectors > 0) {
 204         int64_t position;
 205         int n, nbytes;
 206
 207         qemu_co_mutex_lock(&s->lock);
 208         position = seek_to_sector(s, sector_num);
 209         qemu_co_mutex_unlock(&s->lock);
 210
 211         n = cluster_remainder(s, sector_num, nb_sectors);
 212         nbytes = n << BDRV_SECTOR_BITS;
 213
 214         if (position < 0) {
 215             qemu_iovec_memset(qiov, bytes_done, 0, nbytes);
 216         } else {
 217             qemu_iovec_reset(&hd_qiov);
 218             qemu_iovec_concat(&hd_qiov, qiov, bytes_done, nbytes);
 219
 220             ret = bdrv_co_readv(bs->file, position, n, &hd_qiov);
 221             if (ret < 0) {
 222                 break;
 223             }
 224         }
 225
 226         nb_sectors -= n;
 227         sector_num += n;
 228         bytes_done += nbytes;
 229     }
 230
 231     qemu_iovec_destroy(&hd_qiov);
 232     return ret;
 233 }
 234
 235 static void parallels_close(BlockDriverState *bs)
 236 {
 237     BDRVParallelsState *s = bs->opaque;
 238     g_free(s->catalog_bitmap);
 239 }
 240
 241 static BlockDriver bdrv_parallels = {
 242     .format_name        = "parallels",
 243     .instance_size      = sizeof(BDRVParallelsState),
 244     .bdrv_probe         = parallels_probe,
 245     .bdrv_open          = parallels_open,
 246     .bdrv_close         = parallels_close,
 247     .bdrv_co_get_block_status = parallels_co_get_block_status,
 248     .bdrv_has_zero_init       = bdrv_has_zero_init_1,
 249     .bdrv_co_readv  = parallels_co_readv,
 250 };
 251
 252 static void bdrv_parallels_init(void)
 253 {
 254     bdrv_register(&bdrv_parallels);
 255 }
 256
 257 block_init(bdrv_parallels_init);