summaryrefslogtreecommitdiffstats
path: root/repair.cc
blob: 54a4d895c785612dc99ac38a21b7b48dcc05e706 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/*  Lziprecover - Data recovery tool for the lzip format
    Copyright (C) 2009-2014 Antonio Diaz Diaz.

    This program 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, see <http://www.gnu.org/licenses/>.
*/

#define _FILE_OFFSET_BITS 64

#include <cerrno>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <stdint.h>
#include <unistd.h>
#include <sys/stat.h>

#include "lzip.h"
#include "file_index.h"
#include "mtester.h"


int seek_write( const int fd, const uint8_t * const buf, const int size,
                const long long pos )
  {
  if( lseek( fd, pos, SEEK_SET ) == pos )
    return writeblock( fd, buf, size );
  return 0;
  }


int repair_file( const std::string & input_filename,
                 const std::string & output_filename, const int verbosity,
                 const bool force )
  {
  struct stat in_stats;
  const int infd = open_instream( input_filename.c_str(), &in_stats, true, true );
  if( infd < 0 ) return 1;

  Pretty_print pp( input_filename, verbosity );
  const File_index file_index( infd );
  if( file_index.retval() != 0 )
    { pp( file_index.error().c_str() ); return file_index.retval(); }

  int outfd = -1;
  for( long i = 0; i < file_index.members(); ++i )
    {
    const long long mpos = file_index.mblock( i ).pos();
    const long long msize = file_index.mblock( i ).size();
    if( !safe_seek( infd, mpos ) )
      cleanup_and_fail( output_filename, outfd, 1 );
    long long failure_pos = 0;
    if( try_decompress_member( infd, msize, &failure_pos ) ) continue;
    if( failure_pos >= msize - 8 ) failure_pos = msize - 8 - 1;
    if( failure_pos < File_header::size )
      { show_error( "Can't repair error in input file." );
        cleanup_and_fail( output_filename, outfd, 2 ); }

    if( verbosity >= 1 )		// damaged member found
      {
      std::printf( "Repairing member %ld of %ld  (failure pos = %llu)\n",
                   i + 1, (long)file_index.members(), mpos + failure_pos );
      std::fflush( stdout );
      }
    uint8_t * const mbuffer = read_member( infd, mpos, msize );
    if( !mbuffer )
      cleanup_and_fail( output_filename, outfd, 1 );
    long pos = failure_pos;
    bool done = false;
    while( pos >= File_header::size && pos > failure_pos - 40000 && !done )
      {
      const long min_pos = std::max( (long)File_header::size, pos - 1000 );
      const LZ_mtester * master = prepare_master( mbuffer, msize, min_pos - 16 );
      if( !master )
        cleanup_and_fail( output_filename, outfd, 1 );
      for( ; pos >= min_pos && !done ; --pos )
        {
        if( verbosity >= 1 )
          {
          std::printf( "Trying position %llu \r", mpos + pos );
          std::fflush( stdout );
          }
        for( int j = 0; j < 256; ++j )
          {
          ++mbuffer[pos];
          if( j == 255 ) break;
          if( test_member_rest( *master ) )
            {
            done = true;
            if( outfd < 0 )		// first damaged member repaired
              {
              if( !safe_seek( infd, 0 ) ) return 1;
              outfd = open_outstream_rw( output_filename, force );
              if( outfd < 0 ) { close( infd ); return 1; }
              if( !copy_file( infd, outfd ) )		// copy whole file
                cleanup_and_fail( output_filename, outfd, 1 );
              }
            if( seek_write( outfd, mbuffer + pos, 1, mpos + pos ) != 1 )
              { show_error( "Error writing output file", errno );
                cleanup_and_fail( output_filename, outfd, 1 ); }
            break;
            }
          }
        }
      delete master;
      }
    delete[] mbuffer;
    if( verbosity >= 1 ) std::fputs( "\n", stdout );
    if( !done )
      {
      show_error( "Can't repair input file. Error is probably larger than 1 byte." );
      cleanup_and_fail( output_filename, outfd, 2 );
      }
    }

  if( outfd < 0 )
    {
    if( verbosity >= 1 )
      std::fputs( "Input file has no errors. Recovery is not needed.\n", stdout );
    return 0;
    }
  if( close( outfd ) != 0 )
    {
    show_error( "Error closing output file", errno );
    cleanup_and_fail( output_filename, -1, 1 );
    }
  if( verbosity >= 1 )
    std::fputs( "Copy of input file repaired successfully.\n", stdout );
  return 0;
  }