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/*

    File: file_e01.c

    Copyright (C) 2009 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_e01)
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "types.h"
#include "filegen.h"
#include "common.h"

/*@ requires \valid(file_stat); */
static void register_header_check_e01(file_stat_t *file_stat);

static char ext[10];

const file_hint_t file_hint_e01= {
  .extension="e01",
  .description="Encase",
  .max_filesize=PHOTOREC_MAX_FILE_SIZE,
  .recover=1,
  .enable_by_default=1,
  .register_header_check=&register_header_check_e01
};

struct ewf_file_header
{
        /* The EWF file signature (magic header)
         * consists of 8 bytes containing
         * EVF 0x09 0x0d 0x0a 0xff 0x00
         */
        uint8_t signature[ 8 ];
        /* The fields start
         * consists of 1 byte (8 bit) containing
         * 0x01
         */
        uint8_t fields_start;
        /* The fields segment number
         * consists of 2 bytes (16 bits) containing
         */
        uint16_t fields_segment;
        /* The fields end
         * consists of 2 bytes (16 bits) containing
         * 0x00 0x00
         */
        uint16_t fields_end;
} __attribute__ ((gcc_struct, __packed__));

/*@
  @ requires valid_file_recovery(file_recovery);
  @ requires \valid(file_recovery->handle);
  @ requires \separated(file_recovery, file_recovery->handle, file_recovery->extension, &errno, &Frama_C_entropy_source);
  @ requires file_recovery->file_check == &file_check_e01;
  @ assigns *file_recovery->handle, errno, file_recovery->file_size;
  @ assigns Frama_C_entropy_source;
  @ ensures \valid(file_recovery->handle);
  @*/
static void file_check_e01(file_recovery_t *file_recovery)
{
  const uint64_t tmp=file_recovery->file_size;
  const unsigned char sig_done[16]={
    'd', 'o', 'n', 'e', 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
    };
  const unsigned char sig_next[16]={
    'n', 'e', 'x', 't', 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
    };
  file_search_footer(file_recovery, sig_next, sizeof(sig_next), 60);
  if(file_recovery->file_size!=0)
    return ;
  file_recovery->file_size=tmp;
  file_search_footer(file_recovery, sig_done, sizeof(sig_done), 60);
}

/*@
  @ requires buffer_size >= sizeof(struct ewf_file_header);
  @ requires \valid_read(buffer+(0..buffer_size-1));
  @ requires valid_file_recovery(file_recovery);
  @ requires \valid(file_recovery_new);
  @ requires file_recovery_new->blocksize > 0;
  @ requires separation: \separated(&file_hint_e01, buffer+(..), file_recovery, file_recovery_new);
  @ assigns  *file_recovery_new, *(ext + (0 .. sizeof(ext)-1));
  @ ensures \result == 0 || \result == 1;
  @ ensures  \result!=0 ==> valid_file_recovery(file_recovery_new);
  @*/
static int header_check_e01(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 ewf_file_header *ewf=(const struct ewf_file_header *)buffer;
  uint16_t fields_segment=le16(ewf->fields_segment);
  reset_file_recovery(file_recovery_new);
  if(fields_segment > ('Z'-'E') * 100 + 99)
  {
    ext[0]='E';
    ext[1]='0';
    ext[2]='1';
    ext[3]='_';
    ext[4]='0'+(fields_segment/10000)%10;
    ext[5]='0'+(fields_segment/1000)%10;
    ext[6]='0'+(fields_segment/100)%10;
    ext[7]='0'+(fields_segment/10)%10;
    ext[8]='0'+fields_segment%10;
    ext[9]='\0';
  }
  else
  {
    ext[0]='E'+fields_segment/100;
    ext[1]='0'+(fields_segment/10)%10;
    ext[2]='0'+(fields_segment%10);
    ext[3]='\0';
  }
  file_recovery_new->extension=(const char*)&ext;
  file_recovery_new->file_check=&file_check_e01;
  return 1;
}

static void register_header_check_e01(file_stat_t *file_stat)
{
  static const unsigned char e01_header[9]=  {
    'E' , 'V' , 'F' , 0x09, 0x0d, 0x0a, 0xff, 0x00,
    0x01
  };
  register_header_check(0, e01_header, sizeof(e01_header), &header_check_e01, file_stat);
}
#endif