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 static 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 EIO;
  75
  76         /*No buffering at file.*/
  77         setbuf(dev_file, 0);
  78
  79         if(fseek(dev_file, 0, SEEK_END))
  80                 return EFAULT;
  81
  82         _filedev.ph_bcnt = ftell(dev_file) / _filedev.ph_bsize;
  83
  84         return EOK;
  85 }
  86
  87 /******************************************************************************/
  88
  89 static int filedev_bread(struct  ext4_blockdev *bdev, void *buf, uint64_t blk_id,
  90                 uint32_t blk_cnt)
  91 {
  92         if(fseek(dev_file, blk_id * bdev->ph_bsize, SEEK_SET))
  93                 return EIO;
  94
  95         if(!fread(buf, bdev->ph_bsize * blk_cnt, 1, dev_file))
  96                 return EIO;
  97
  98         return EOK;
  99 }
 100
 101 /******************************************************************************/
 102 static int filedev_bwrite(struct ext4_blockdev *bdev, const void *buf,
 103                 uint64_t blk_id, uint32_t blk_cnt)
 104 {
 105         if(fseek(dev_file, blk_id * bdev->ph_bsize, SEEK_SET))
 106                 return EIO;
 107
 108         if(!fwrite(buf, bdev->ph_bsize * blk_cnt, 1, dev_file))
 109                 return EIO;
 110         return EOK;
 111 }
 112
 113 /******************************************************************************/
 114 static int filedev_close(struct  ext4_blockdev *bdev)
 115 {
 116         fclose(dev_file);
 117         return EOK;
 118 }
 119
 120
 121 /******************************************************************************/
 122
 123 struct  ext4_bcache* ext4_filecache_get(void)
 124 {
 125         return &__cache;
 126 }
 127 /******************************************************************************/
 128 struct  ext4_blockdev* ext4_filedev_get(void)
 129 {
 130         return &_filedev;
 131 }
 132 /******************************************************************************/
 133 void ext4_filedev_filename(const char *n)
 134 {
 135         fname = n;
 136 }
 137
 138 /******************************************************************************/