summaryrefslogtreecommitdiffstats
path: root/file_index.cc
blob: b4f54201ada7aef80ff5c757e61eed4b2c7cb711 (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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
/*  Lziprecover - Data recovery tool for lzip files
    Copyright (C) 2009, 2010, 2011, 2012, 2013, 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 3 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/>.
*/

#include <algorithm>
#include <cerrno>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <stdint.h>
#include <unistd.h>

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


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


Block Block::split( const long long pos )
  {
  if( pos > pos_ && pos < end() )
    {
    const Block b( pos_, pos - pos_ );
    pos_ = pos; size_ -= b.size_;
    return b;
    }
  return Block( 0, 0 );
  }


void File_index::set_errno_error( const char * const msg )
  {
  error_ = msg; error_ += std::strerror( errno ); error_ += '.';
  retval_ = 1;
  }

void File_index::set_num_error( const char * const msg1, unsigned long long num,
                                const char * const msg2 )
  {
  char buf[80];
  snprintf( buf, sizeof buf, "%s%llu%s", msg1, num, msg2 );
  error_ = buf;
  retval_ = 2;
  }


File_index::File_index( const int infd )
  : isize( lseek( infd, 0, SEEK_END ) ), retval_( 0 )
  {
  if( isize < 0 )
    { set_errno_error( "Input file is not seekable :" ); return; }
  if( isize < min_member_size )
    { error_ = "Input file is too short."; retval_ = 2; return; }
  if( isize > INT64_MAX )
    { error_ = "Input file is too long (2^63 bytes or more).";
      retval_ = 2; return; }

  File_header header;
  if( seek_read( infd, header.data, File_header::size, 0 ) != File_header::size )
    { set_errno_error( "Error reading member header :" ); return; }
  if( !header.verify_magic() )
    { error_ = "Bad magic number (file not in lzip format).";
      retval_ = 2; return; }
  if( !header.verify_version() )
    { set_num_error( "Version ", header.version(),
                     " member format not supported." ); return; }

  long long pos = isize;		// always points to a header or to EOF
  while( pos >= min_member_size )
    {
    File_trailer trailer;
    if( seek_read( infd, trailer.data, File_trailer::size,
                   pos - File_trailer::size ) != File_trailer::size )
      { set_errno_error( "Error reading member trailer :" ); break; }
    const long long member_size = trailer.member_size();
    if( member_size < min_member_size || member_size > pos )
      {
      if( member_vector.empty() )		// maybe trailing garbage
        { --pos; continue; }
      set_num_error( "Member size in trailer is corrupt at pos ", pos - 8 );
      break;
      }
    if( seek_read( infd, header.data, File_header::size,
                   pos - member_size ) != File_header::size )
      { set_errno_error( "Error reading member header :" ); break; }
    if( !header.verify_magic() || !header.verify_version() )
      {
      if( member_vector.empty() )		// maybe trailing garbage
        { --pos; continue; }
      set_num_error( "Bad header at pos ", pos - member_size );
      break;
      }
    if( member_vector.empty() && isize - pos > File_header::size &&
        seek_read( infd, header.data, File_header::size, pos ) == File_header::size &&
        header.verify_magic() && header.verify_version() )
      {
      error_ = "Last member in input file is truncated or corrupt.";
      retval_ = 2; break;
      }
    pos -= member_size;
    member_vector.push_back( Member( 0, trailer.data_size(),
                                     pos, member_size ) );
    }
  if( pos != 0 || member_vector.empty() )
    {
    member_vector.clear();
    if( retval_ == 0 ) { error_ = "Can't create file index."; retval_ = 2; }
    return;
    }
  std::reverse( member_vector.begin(), member_vector.end() );
  for( unsigned long i = 0; i < member_vector.size() - 1; ++i )
    {
    const long long end = member_vector[i].dblock.end();
    if( end < 0 || end > INT64_MAX )
      {
      member_vector.clear();
      error_ = "Data in input file is too long (2^63 bytes or more).";
      retval_ = 2; return;
      }
    member_vector[i+1].dblock.pos( end );
    }
  }


// All files in 'infd_vector' must be at least 'fsize' bytes long.
File_index::File_index( const std::vector< int > & infd_vector,
                        const long long fsize )
  : isize( fsize ), retval_( 0 )
  {
  if( isize < 0 )
    { set_errno_error( "Input file is not seekable :" ); return; }
  if( isize < min_member_size )
    { error_ = "Input file is too short."; retval_ = 2; return; }
  if( isize > INT64_MAX )
    { error_ = "Input file is too long (2^63 bytes or more).";
      retval_ = 2; return; }

  const int files = infd_vector.size();
  File_header header;
  bool done = false;
  for( int i = 0; i < files && !done; ++i )
    {
    const int infd = infd_vector[i];
    if( seek_read( infd, header.data, File_header::size, 0 ) != File_header::size )
      { set_errno_error( "Error reading member header :" ); return; }
    if( header.verify_magic() && header.verify_version() ) done = true;
    }
  if( !done )
    { error_ = "Bad magic number (file not in lzip format).";
      retval_ = 2; return; }

  long long pos = isize;		// always points to a header or to EOF
  while( pos >= min_member_size )
    {
    long long member_size;
    File_trailer trailer;
    done = false;
    for( int it = 0; it < files && !done; ++it )
      {
      const int tfd = infd_vector[it];
      if( seek_read( tfd, trailer.data, File_trailer::size,
                     pos - File_trailer::size ) != File_trailer::size )
        { set_errno_error( "Error reading member trailer :" ); goto error; }
      member_size = trailer.member_size();
      if( member_size >= min_member_size && member_size <= pos )
        for( int ih = 0; ih < files && !done; ++ih )
          {
          const int hfd = infd_vector[ih];
          if( seek_read( hfd, header.data, File_header::size,
                         pos - member_size ) != File_header::size )
            { set_errno_error( "Error reading member header :" ); goto error; }
          if( header.verify_magic() && header.verify_version() ) done = true;
          }
      }
    if( !done )
      {
      if( member_vector.empty() )		// maybe trailing garbage
        { --pos; continue; }
      set_num_error( "Member size in trailer may be corrupt at pos ", pos - 8 );
      break;
      }
    if( member_vector.empty() && isize - pos > File_header::size )
      for( int i = 0; i < files; ++i )
        {
        const int infd = infd_vector[i];
        if( seek_read( infd, header.data, File_header::size, pos ) == File_header::size &&
            header.verify_magic() && header.verify_version() )
          {
          error_ = "Last member in input file is truncated or corrupt.";
          retval_ = 2; goto error;
          }
        }
    pos -= member_size;
    member_vector.push_back( Member( 0, trailer.data_size(),
                                     pos, member_size ) );
    }
error:
  if( pos != 0 || member_vector.empty() )
    {
    member_vector.clear();
    if( retval_ == 0 ) { error_ = "Can't create file index."; retval_ = 2; }
    return;
    }
  std::reverse( member_vector.begin(), member_vector.end() );
  for( unsigned long i = 0; i < member_vector.size() - 1; ++i )
    {
    const long long end = member_vector[i].dblock.end();
    if( end < 0 || end > INT64_MAX )
      {
      member_vector.clear();
      error_ = "Data in input file is too long (2^63 bytes or more).";
      retval_ = 2; return;
      }
    member_vector[i+1].dblock.pos( end );
    }
  }