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
  64     bool has_truncate;
  65 } BDRVParallelsState;
  66
  67 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
  68 {
  69     const ParallelsHeader *ph = (const void *)buf;
  70
  71     if (buf_size < sizeof(ParallelsHeader))
  72         return 0;
  73
  74     if ((!memcmp(ph->magic, HEADER_MAGIC, 16) ||
  75         !memcmp(ph->magic, HEADER_MAGIC2, 16)) &&
  76         (le32_to_cpu(ph->version) == HEADER_VERSION))
  77         return 100;
  78
  79     return 0;
  80 }
  81
  82 static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
  83                           Error **errp)
  84 {
  85     BDRVParallelsState *s = bs->opaque;
  86     int i;
  87     ParallelsHeader ph;
  88     int ret;
  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     s->has_truncate = bdrv_has_zero_init(bs->file) &&
 143                       bdrv_truncate(bs->file, bdrv_getlength(bs->file)) == 0;
 144
 145     qemu_co_mutex_init(&s->lock);
 146     return 0;
 147
 148 fail_format:
 149     error_setg(errp, "Image not in Parallels format");
 150     ret = -EINVAL;
 151 fail:
 152     g_free(s->catalog_bitmap);
 153     return ret;
 154 }
 155
 156 static int64_t seek_to_sector(BDRVParallelsState *s, int64_t sector_num)
 157 {
 158     uint32_t index, offset;
 159
 160     index = sector_num / s->tracks;
 161     offset = sector_num % s->tracks;
 162
 163     /* not allocated */
 164     if ((index >= s->catalog_size) || (s->catalog_bitmap[index] == 0))
 165         return -1;
 166     return (uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset;
 167 }
 168
 169 static int cluster_remainder(BDRVParallelsState *s, int64_t sector_num,
 170         int nb_sectors)
 171 {
 172     int ret = s->tracks - sector_num % s->tracks;
 173     return MIN(nb_sectors, ret);
 174 }
 175
 176 static int64_t allocate_cluster(BlockDriverState *bs, int64_t sector_num)
 177 {
 178     BDRVParallelsState *s = bs->opaque;
 179     uint32_t idx, offset, tmp;
 180     int64_t pos;
 181     int ret;
 182
 183     idx = sector_num / s->tracks;
 184     offset = sector_num % s->tracks;
 185
 186     if (idx >= s->catalog_size) {
 187         return -EINVAL;
 188     }
 189     if (s->catalog_bitmap[idx] != 0) {
 190         return (uint64_t)s->catalog_bitmap[idx] * s->off_multiplier + offset;
 191     }
 192
 193     pos = bdrv_getlength(bs->file) >> BDRV_SECTOR_BITS;
 194     if (s->has_truncate) {
 195         ret = bdrv_truncate(bs->file, (pos + s->tracks) << BDRV_SECTOR_BITS);
 196     } else {
 197         ret = bdrv_write_zeroes(bs->file, pos, s->tracks, 0);
 198     }
 199     if (ret < 0) {
 200         return ret;
 201     }
 202
 203     s->catalog_bitmap[idx] = pos / s->off_multiplier;
 204
 205     tmp = cpu_to_le32(s->catalog_bitmap[idx]);
 206
 207     ret = bdrv_pwrite(bs->file,
 208             sizeof(ParallelsHeader) + idx * sizeof(tmp), &tmp, sizeof(tmp));
 209     if (ret < 0) {
 210         s->catalog_bitmap[idx] = 0;
 211         return ret;
 212     }
 213     return (uint64_t)s->catalog_bitmap[idx] * s->off_multiplier + offset;
 214 }
 215
 216 static int64_t coroutine_fn parallels_co_get_block_status(BlockDriverState *bs,
 217         int64_t sector_num, int nb_sectors, int *pnum)
 218 {
 219     BDRVParallelsState *s = bs->opaque;
 220     int64_t offset;
 221
 222     qemu_co_mutex_lock(&s->lock);
 223     offset = seek_to_sector(s, sector_num);
 224     qemu_co_mutex_unlock(&s->lock);
 225
 226     *pnum = cluster_remainder(s, sector_num, nb_sectors);
 227
 228     if (offset < 0) {
 229         return 0;
 230     }
 231
 232     return (offset << BDRV_SECTOR_BITS) |
 233         BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
 234 }
 235
 236 static coroutine_fn int parallels_co_writev(BlockDriverState *bs,
 237         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
 238 {
 239     BDRVParallelsState *s = bs->opaque;
 240     uint64_t bytes_done = 0;
 241     QEMUIOVector hd_qiov;
 242     int ret = 0;
 243
 244     qemu_iovec_init(&hd_qiov, qiov->niov);
 245
 246     while (nb_sectors > 0) {
 247         int64_t position;
 248         int n, nbytes;
 249
 250         qemu_co_mutex_lock(&s->lock);
 251         position = allocate_cluster(bs, sector_num);
 252         qemu_co_mutex_unlock(&s->lock);
 253         if (position < 0) {
 254             ret = (int)position;
 255             break;
 256         }
 257
 258         n = cluster_remainder(s, sector_num, nb_sectors);
 259         nbytes = n << BDRV_SECTOR_BITS;
 260
 261         qemu_iovec_reset(&hd_qiov);
 262         qemu_iovec_concat(&hd_qiov, qiov, bytes_done, nbytes);
 263
 264         ret = bdrv_co_writev(bs->file, position, n, &hd_qiov);
 265         if (ret < 0) {
 266             break;
 267         }
 268
 269         nb_sectors -= n;
 270         sector_num += n;
 271         bytes_done += nbytes;
 272     }
 273
 274     qemu_iovec_destroy(&hd_qiov);
 275     return ret;
 276 }
 277
 278 static coroutine_fn int parallels_co_readv(BlockDriverState *bs,
 279         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
 280 {
 281     BDRVParallelsState *s = bs->opaque;
 282     uint64_t bytes_done = 0;
 283     QEMUIOVector hd_qiov;
 284     int ret = 0;
 285
 286     qemu_iovec_init(&hd_qiov, qiov->niov);
 287
 288     while (nb_sectors > 0) {
 289         int64_t position;
 290         int n, nbytes;
 291
 292         qemu_co_mutex_lock(&s->lock);
 293         position = seek_to_sector(s, sector_num);
 294         qemu_co_mutex_unlock(&s->lock);
 295
 296         n = cluster_remainder(s, sector_num, nb_sectors);
 297         nbytes = n << BDRV_SECTOR_BITS;
 298
 299         if (position < 0) {
 300             qemu_iovec_memset(qiov, bytes_done, 0, nbytes);
 301         } else {
 302             qemu_iovec_reset(&hd_qiov);
 303             qemu_iovec_concat(&hd_qiov, qiov, bytes_done, nbytes);
 304
 305             ret = bdrv_co_readv(bs->file, position, n, &hd_qiov);
 306             if (ret < 0) {
 307                 break;
 308             }
 309         }
 310
 311         nb_sectors -= n;
 312         sector_num += n;
 313         bytes_done += nbytes;
 314     }
 315
 316     qemu_iovec_destroy(&hd_qiov);
 317     return ret;
 318 }
 319
 320 static void parallels_close(BlockDriverState *bs)
 321 {
 322     BDRVParallelsState *s = bs->opaque;
 323     g_free(s->catalog_bitmap);
 324 }
 325
 326 static BlockDriver bdrv_parallels = {
 327     .format_name        = "parallels",
 328     .instance_size      = sizeof(BDRVParallelsState),
 329     .bdrv_probe         = parallels_probe,
 330     .bdrv_open          = parallels_open,
 331     .bdrv_close         = parallels_close,
 332     .bdrv_co_get_block_status = parallels_co_get_block_status,
 333     .bdrv_has_zero_init       = bdrv_has_zero_init_1,
 334     .bdrv_co_readv  = parallels_co_readv,
 335     .bdrv_co_writev = parallels_co_writev,
 336 };
 337
 338 static void bdrv_parallels_init(void)
 339 {
 340     bdrv_register(&bdrv_parallels);
 341 }
 342
 343 block_init(bdrv_parallels_init);