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_RDONLY | O_BINARY | O_LARGEFILE);
  78     if (fd < 0) {
  79         return -1;
  80     }
  81
  82     bs->read_only = 1; // no write support yet
  83
  84     s->fd = fd;
  85
  86     if (read(fd, &ph, sizeof(ph)) != sizeof(ph))
  87         goto fail;
  88
  89     if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
  90         (le32_to_cpu(ph.version) != HEADER_VERSION)) {
  91         goto fail;
  92     }
  93
  94     bs->total_sectors = le32_to_cpu(ph.nb_sectors);
  95
  96     if (lseek(s->fd, 64, SEEK_SET) != 64)
  97         goto fail;
  98
  99     s->tracks = le32_to_cpu(ph.tracks);
 100
 101     s->catalog_size = le32_to_cpu(ph.catalog_entries);
 102     s->catalog_bitmap = qemu_malloc(s->catalog_size * 4);
 103     if (read(s->fd, s->catalog_bitmap, s->catalog_size * 4) !=
 104         s->catalog_size * 4)
 105         goto fail;
 106     for (i = 0; i < s->catalog_size; i++)
 107         le32_to_cpus(&s->catalog_bitmap[i]);
 108
 109     return 0;
 110 fail:
 111     if (s->catalog_bitmap)
 112         qemu_free(s->catalog_bitmap);
 113     close(fd);
 114     return -1;
 115 }
 116
 117 static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 118 {
 119     BDRVParallelsState *s = bs->opaque;
 120     uint32_t index, offset;
 121     uint64_t position;
 122
 123     index = sector_num / s->tracks;
 124     offset = sector_num % s->tracks;
 125
 126     // not allocated
 127     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
 128         return -1;
 129
 130     position = (uint64_t)(s->catalog_bitmap[index] + offset) * 512;
 131
 132 //    fprintf(stderr, "sector: %llx index=%x offset=%x pointer=%x position=%x\n",
 133 //      sector_num, index, offset, s->catalog_bitmap[index], position);
 134
 135     if (lseek(s->fd, position, SEEK_SET) != position)
 136         return -1;
 137
 138     return 0;
 139 }
 140
 141 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
 142                     uint8_t *buf, int nb_sectors)
 143 {
 144     BDRVParallelsState *s = bs->opaque;
 145
 146     while (nb_sectors > 0) {
 147         if (!seek_to_sector(bs, sector_num)) {
 148             if (read(s->fd, buf, 512) != 512)
 149                 return -1;
 150         } else
 151             memset(buf, 0, 512);
 152         nb_sectors--;
 153         sector_num++;
 154         buf += 512;
 155     }
 156     return 0;
 157 }
 158
 159 static void parallels_close(BlockDriverState *bs)
 160 {
 161     BDRVParallelsState *s = bs->opaque;
 162     qemu_free(s->catalog_bitmap);
 163     close(s->fd);
 164 }
 165
 166 static BlockDriver bdrv_parallels = {
 167     .format_name        = "parallels",
 168     .instance_size      = sizeof(BDRVParallelsState),
 169     .bdrv_probe         = parallels_probe,
 170     .bdrv_open          = parallels_open,
 171     .bdrv_read          = parallels_read,
 172     .bdrv_close         = parallels_close,
 173 };
 174
 175 static void bdrv_parallels_init(void)
 176 {
 177     bdrv_register(&bdrv_parallels);
 178 }
 179
 180 block_init(bdrv_parallels_init);