/*

    File: file_ext2_fs.c

    Copyright (C) 1998-2005,2007 Christophe GRENIER <grenier@cgsecurity.org>
  
    This software is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
  
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
  
    You should have received a copy of the GNU General Public License along
    with this program; if not, write the Free Software Foundation, Inc., 51
    Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_ext2_fs)
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "types.h"
#include "common.h"
#include "ext2_common.h"
#include "filegen.h"

/*@ requires valid_register_header_check(file_stat); */
static void register_header_check_ext2_fs(file_stat_t *file_stat);

const file_hint_t file_hint_ext2_fs= {
  .extension="ext2",
  .description="ext2/ext3/ext4 Filesystem",
  .max_filesize=0,
  .recover=1,
  .enable_by_default=0,
  .register_header_check=&register_header_check_ext2_fs
};

/*@
  @ requires buffer_size >= sizeof(struct ext2_super_block);
  @ requires separation: \separated(&file_hint_ext2_fs, buffer+(..), file_recovery, file_recovery_new);
  @ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new);
  @ ensures  valid_header_check_result(\result, file_recovery_new);
  @*/
static int header_check_ext2_fs(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
{
  const struct ext2_super_block *sb=(const struct ext2_super_block *)&buffer[0x400];
  if(test_EXT2(sb, NULL)!=0)
    return 0;
  /*@ assert le32(sb->s_log_block_size) <= 6; */
  if(le16(sb->s_block_group_nr)!=0)
    return 0;
  if(file_recovery->file_stat!=NULL &&
       file_recovery->file_stat->file_hint==&file_hint_ext2_fs &&
       file_recovery->calculated_file_size==(uint64_t)le32(sb->s_blocks_count)*(EXT2_MIN_BLOCK_SIZE<<le32(sb->s_log_block_size)))
  {
    if(header_ignored_adv(file_recovery, file_recovery_new)==0)
      return 0;
  }
  reset_file_recovery(file_recovery_new);
  file_recovery_new->extension=file_hint_ext2_fs.extension;
  file_recovery_new->calculated_file_size=(uint64_t)le32(sb->s_blocks_count)*(EXT2_MIN_BLOCK_SIZE<<le32(sb->s_log_block_size));
  file_recovery_new->data_check=&data_check_size;
  file_recovery_new->file_check=&file_check_size;
  return 1;
}

static void register_header_check_ext2_fs(file_stat_t *file_stat)
{
  static const unsigned char ext2_fs_header[2]= {0x53, 0xEF};
  register_header_check(0x438, ext2_fs_header,sizeof(ext2_fs_header), &header_check_ext2_fs, file_stat);
}
#endif
