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_int.h"
  28
  29 /**************************************************************/
  30
  31 #define HEADER_MAGIC "WithoutFreeSpace"
  32 #define HEADER_VERSION 2
  33 #define HEADER_SIZE 64
  34
  35 // always little-endian
  36 struct parallels_header {
  37     char magic[16]; // "WithoutFreeSpace"
  38     uint32_t version;
  39     uint32_t heads;
  40     uint32_t cylinders;
  41     uint32_t tracks;
  42     uint32_t catalog_entries;
  43     uint32_t nb_sectors;
  44     char padding[24];
  45 } __attribute__((packed));
  46
  47 typedef struct BDRVParallelsState {
  48     int fd;
  49
  50     uint32_t *catalog_bitmap;
  51     int catalog_size;
  52
  53     int tracks;
  54 } BDRVParallelsState;
  55
  56 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
  57 {
  58     const struct parallels_header *ph = (const void *)buf;
  59
  60     if (buf_size < HEADER_SIZE)
  61         return 0;
  62
  63     if (!memcmp(ph->magic, HEADER_MAGIC, 16) &&
  64         (le32_to_cpu(ph->version) == HEADER_VERSION))
  65         return 100;
  66
  67     return 0;
  68 }
  69
  70 static int parallels_open(BlockDriverState *bs, const char *filename, int flags)
  71 {
  72     BDRVParallelsState *s = bs->opaque;
  73     int fd, i;
  74     struct parallels_header ph;
  75
  76     fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
  77     if (fd < 0) {
  78         fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
  79         if (fd < 0)
  80             return -1;
  81     }
  82
  83     bs->read_only = 1; // no write support yet
  84
  85     s->fd = fd;
  86
  87     if (read(fd, &ph, sizeof(ph)) != sizeof(ph))
  88         goto fail;
  89
  90     if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
  91         (le32_to_cpu(ph.version) != HEADER_VERSION)) {
  92         goto fail;
  93     }
  94
  95     bs->total_sectors = le32_to_cpu(ph.nb_sectors);
  96
  97     if (lseek(s->fd, 64, SEEK_SET) != 64)
  98         goto fail;
  99
 100     s->tracks = le32_to_cpu(ph.tracks);
 101
 102     s->catalog_size = le32_to_cpu(ph.catalog_entries);
 103     s->catalog_bitmap = qemu_malloc(s->catalog_size * 4);
 104     if (!s->catalog_bitmap)
 105         goto fail;
 106     if (read(s->fd, s->catalog_bitmap, s->catalog_size * 4) !=
 107         s->catalog_size * 4)
 108         goto fail;
 109     for (i = 0; i < s->catalog_size; i++)
 110         le32_to_cpus(&s->catalog_bitmap[i]);
 111
 112     return 0;
 113 fail:
 114     if (s->catalog_bitmap)
 115         qemu_free(s->catalog_bitmap);
 116     close(fd);
 117     return -1;
 118 }
 119
 120 static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 121 {
 122     BDRVParallelsState *s = bs->opaque;
 123     uint32_t index, offset, position;
 124
 125     index = sector_num / s->tracks;
 126     offset = sector_num % s->tracks;
 127
 128     // not allocated
 129     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 130         return -1;
 131
 132     position = (s->catalog_bitmap[index] + offset) * 512;
 133
 134 //    fprintf(stderr, "sector: %llx index=%x offset=%x pointer=%x position=%x\n",
 135 //      sector_num, index, offset, s->catalog_bitmap[index], position);
 136
 137     if (lseek(s->fd, position, SEEK_SET) != position)
 138         return -1;
 139
 140     return 0;
 141 }
 142
 143 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 144                     uint8_t *buf, int nb_sectors)
 145 {
 146     BDRVParallelsState *s = bs->opaque;
 147
 148     while (nb_sectors > 0) {
 149         if (!seek_to_sector(bs, sector_num)) {
 150             if (read(s->fd, buf, 512) != 512)
 151                 return -1;
 152         } else
 153             memset(buf, 0, 512);
 154         nb_sectors--;
 155         sector_num++;
 156         buf += 512;
 157     }
 158     return 0;
 159 }
 160
 161 static void parallels_close(BlockDriverState *bs)
 162 {
 163     BDRVParallelsState *s = bs->opaque;
 164     qemu_free(s->catalog_bitmap);
 165     close(s->fd);
 166 }
 167
 168 BlockDriver bdrv_parallels = {
 169     "parallels",
 170     sizeof(BDRVParallelsState),
 171     parallels_probe,
 172     parallels_open,
 173     parallels_read,
 174     NULL,
 175     parallels_close,
 176 };