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 #include "module.h"
  29
  30 /**************************************************************/
  31
  32 #define HEADER_MAGIC "WithoutFreeSpace"
  33 #define HEADER_VERSION 2
  34 #define HEADER_SIZE 64
  35
  36 // always little-endian
  37 struct parallels_header {
  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     uint32_t nb_sectors;
  45     char padding[24];
  46 } __attribute__((packed));
  47
  48 typedef struct BDRVParallelsState {
  49     int fd;
  50
  51     uint32_t *catalog_bitmap;
  52     int catalog_size;
  53
  54     int tracks;
  55 } BDRVParallelsState;
  56
  57 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
  58 {
  59     const struct parallels_header *ph = (const void *)buf;
  60
  61     if (buf_size < HEADER_SIZE)
  62         return 0;
  63
  64     if (!memcmp(ph->magic, HEADER_MAGIC, 16) &&
  65         (le32_to_cpu(ph->version) == HEADER_VERSION))
  66         return 100;
  67
  68     return 0;
  69 }
  70
  71 static int parallels_open(BlockDriverState *bs, const char *filename, int flags)
  72 {
  73     BDRVParallelsState *s = bs->opaque;
  74     int fd, i;
  75     struct parallels_header ph;
  76
  77     fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
  78     if (fd < 0) {
  79         fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
  80         if (fd < 0)
  81             return -1;
  82     }
  83
  84     bs->read_only = 1; // no write support yet
  85
  86     s->fd = fd;
  87
  88     if (read(fd, &ph, sizeof(ph)) != sizeof(ph))
  89         goto fail;
  90
  91     if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
  92         (le32_to_cpu(ph.version) != HEADER_VERSION)) {
  93         goto fail;
  94     }
  95
  96     bs->total_sectors = le32_to_cpu(ph.nb_sectors);
  97
  98     if (lseek(s->fd, 64, SEEK_SET) != 64)
  99         goto fail;
 100
 101     s->tracks = le32_to_cpu(ph.tracks);
 102
 103     s->catalog_size = le32_to_cpu(ph.catalog_entries);
 104     s->catalog_bitmap = qemu_malloc(s->catalog_size * 4);
 105     if (read(s->fd, s->catalog_bitmap, s->catalog_size * 4) !=
 106         s->catalog_size * 4)
 107         goto fail;
 108     for (i = 0; i < s->catalog_size; i++)
 109         le32_to_cpus(&s->catalog_bitmap[i]);
 110
 111     return 0;
 112 fail:
 113     if (s->catalog_bitmap)
 114         qemu_free(s->catalog_bitmap);
 115     close(fd);
 116     return -1;
 117 }
 118
 119 static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 120 {
 121     BDRVParallelsState *s = bs->opaque;
 122     uint32_t index, offset, position;
 123
 124     index = sector_num / s->tracks;
 125     offset = sector_num % s->tracks;
 126
 127     // not allocated
 128     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 129         return -1;
 130
 131     position = (s->catalog_bitmap[index] + offset) * 512;
 132
 133 //    fprintf(stderr, "sector: %llx index=%x offset=%x pointer=%x position=%x\n",
 134 //      sector_num, index, offset, s->catalog_bitmap[index], position);
 135
 136     if (lseek(s->fd, position, SEEK_SET) != position)
 137         return -1;
 138
 139     return 0;
 140 }
 141
 142 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 143                     uint8_t *buf, int nb_sectors)
 144 {
 145     BDRVParallelsState *s = bs->opaque;
 146
 147     while (nb_sectors > 0) {
 148         if (!seek_to_sector(bs, sector_num)) {
 149             if (read(s->fd, buf, 512) != 512)
 150                 return -1;
 151         } else
 152             memset(buf, 0, 512);
 153         nb_sectors--;
 154         sector_num++;
 155         buf += 512;
 156     }
 157     return 0;
 158 }
 159
 160 static void parallels_close(BlockDriverState *bs)
 161 {
 162     BDRVParallelsState *s = bs->opaque;
 163     qemu_free(s->catalog_bitmap);
 164     close(s->fd);
 165 }
 166
 167 static BlockDriver bdrv_parallels = {
 168     .format_name        = "parallels",
 169     .instance_size      = sizeof(BDRVParallelsState),
 170     .bdrv_probe         = parallels_probe,
 171     .bdrv_open          = parallels_open,
 172     .bdrv_read          = parallels_read,
 173     .bdrv_close         = parallels_close,
 174 };
 175
 176 static void bdrv_parallels_init(void)
 177 {
 178     bdrv_register(&bdrv_parallels);
 179 }
 180
 181 block_init(bdrv_parallels_init);