blockdev/filedev/ext4_filedev.c

   1 /*
   2  * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28 #include <ext4_config.h>
  29 #include <ext4_blockdev.h>
  30 #include <ext4_errno.h>
  31 #include <stdio.h>
  32 #include <stdbool.h>
  33 #include <string.h>
  34
  35 /**@brief       Default filename.*/
  36 const char *fname = "ext2";
  37
  38 /**@brief       Image block size.*/
  39 #define EXT4_FILEDEV_BSIZE              512
  40
  41 /**@brief       Image file descriptor.*/
  42 static FILE     *dev_file;
  43
  44
  45 /**********************BLOCKDEV INTERFACE**************************************/
  46 static int filedev_open(struct ext4_blockdev *bdev);
  47 static int filedev_bread(struct ext4_blockdev *bdev, void *buf, uint64_t blk_id,
  48                 uint32_t blk_cnt);
  49 static int filedev_bwrite(struct ext4_blockdev *bdev, const void *buf,
  50                 uint64_t blk_id, uint32_t blk_cnt);
  51 static int filedev_close(struct  ext4_blockdev *bdev);
  52
  53
  54 /******************************************************************************/
  55 EXT4_BLOCKDEV_STATIC_INSTANCE(
  56                 _filedev,
  57                 EXT4_FILEDEV_BSIZE,
  58                 0,
  59                 filedev_open,
  60                 filedev_bread,
  61                 filedev_bwrite,
  62                 filedev_close
  63 );
  64
  65 /******************************************************************************/
  66 EXT4_BCACHE_STATIC_INSTANCE(__cache, 8, 1024);
  67
  68 /******************************************************************************/
  69 static int filedev_open(struct ext4_blockdev *bdev)
  70 {
  71         dev_file = fopen(fname, "r+b");
  72
  73         if(!dev_file)
  74                 return ENOENT;
  75
  76         if(fseek(dev_file, 0, SEEK_END))
  77                 return EFAULT;
  78
  79         _filedev.ph_bcnt = ftell(dev_file) / _filedev.ph_bsize;
  80
  81         return EOK;
  82 }
  83
  84 /******************************************************************************/
  85
  86 static int filedev_bread(struct  ext4_blockdev *bdev, void *buf, uint64_t blk_id,
  87                 uint32_t blk_cnt)
  88 {
  89         if(fseek(dev_file, blk_id * bdev->ph_bsize, SEEK_SET))
  90                 return EIO;
  91
  92         if(!fread(buf, bdev->ph_bsize * blk_cnt, 1, dev_file))
  93                 return EIO;
  94
  95         return EOK;
  96 }
  97
  98 /******************************************************************************/
  99 static int filedev_bwrite(struct ext4_blockdev *bdev, const void *buf,
 100                 uint64_t blk_id, uint32_t blk_cnt)
 101 {
 102         if(fseek(dev_file, blk_id * bdev->ph_bsize, SEEK_SET))
 103                 return EIO;
 104
 105         if(!fwrite(buf, bdev->ph_bsize * blk_cnt, 1, dev_file))
 106                 return EIO;
 107         return EOK;
 108 }
 109
 110 /******************************************************************************/
 111 static int filedev_close(struct  ext4_blockdev *bdev)
 112 {
 113         fclose(dev_file);
 114         return EOK;
 115 }
 116
 117
 118 /******************************************************************************/
 119
 120 struct  ext4_bcache* ext4_filecache_get(void)
 121 {
 122         return &__cache;
 123 }
 124 /******************************************************************************/
 125 struct  ext4_blockdev* ext4_filedev_get(void)
 126 {
 127         return &_filedev;
 128 }
 129 /******************************************************************************/
 130 void ext4_filedev_filename(const char *n)
 131 {
 132         fname = n;
 133 }
 134
 135 /******************************************************************************/