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 typedef struct ParallelsHeader {
  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 ParallelsHeader;
  50
  51 typedef struct BDRVParallelsState {
  52     /** Locking is conservative, the lock protects
  53      *   - image file extending (truncate, fallocate)
  54      *   - any access to block allocation table
  55      */
  56     CoMutex lock;
  57
  58     uint32_t *catalog_bitmap;
  59     unsigned int catalog_size;
  60
  61     unsigned int tracks;
  62
  63     unsigned int off_multiplier;
  64 } BDRVParallelsState;
  65
  66 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
  67 {
  68     const ParallelsHeader *ph = (const void *)buf;
  69
  70     if (buf_size < HEADER_SIZE)
  71         return 0;
  72
  73     if ((!memcmp(ph->magic, HEADER_MAGIC, 16) ||
  74         !memcmp(ph->magic, HEADER_MAGIC2, 16)) &&
  75         (le32_to_cpu(ph->version) == HEADER_VERSION))
  76         return 100;
  77
  78     return 0;
  79 }
  80
  81 static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
  82                           Error **errp)
  83 {
  84     BDRVParallelsState *s = bs->opaque;
  85     int i;
  86     ParallelsHeader ph;
  87     int ret;
  88
  89     bs->read_only = 1; // no write support yet
  90
  91     ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));
  92     if (ret < 0) {
  93         goto fail;
  94     }
  95
  96     bs->total_sectors = le64_to_cpu(ph.nb_sectors);
  97
  98     if (le32_to_cpu(ph.version) != HEADER_VERSION) {
  99         goto fail_format;
 100     }
 101     if (!memcmp(ph.magic, HEADER_MAGIC, 16)) {
 102         s->off_multiplier = 1;
 103         bs->total_sectors = 0xffffffff & bs->total_sectors;
 104     } else if (!memcmp(ph.magic, HEADER_MAGIC2, 16)) {
 105         s->off_multiplier = le32_to_cpu(ph.tracks);
 106     } else {
 107         goto fail_format;
 108     }
 109
 110     s->tracks = le32_to_cpu(ph.tracks);
 111     if (s->tracks == 0) {
 112         error_setg(errp, "Invalid image: Zero sectors per track");
 113         ret = -EINVAL;
 114         goto fail;
 115     }
 116     if (s->tracks > INT32_MAX/513) {
 117         error_setg(errp, "Invalid image: Too big cluster");
 118         ret = -EFBIG;
 119         goto fail;
 120     }
 121
 122     s->catalog_size = le32_to_cpu(ph.catalog_entries);
 123     if (s->catalog_size > INT_MAX / 4) {
 124         error_setg(errp, "Catalog too large");
 125         ret = -EFBIG;
 126         goto fail;
 127     }
 128     s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
 129     if (s->catalog_size && s->catalog_bitmap == NULL) {
 130         ret = -ENOMEM;
 131         goto fail;
 132     }
 133
 134     ret = bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4);
 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_co_readv  = parallels_co_readv,
 249 };
 250
 251 static void bdrv_parallels_init(void)
 252 {
 253     bdrv_register(&bdrv_parallels);
 254 }
 255
 256 block_init(bdrv_parallels_init);