286 lines
10 KiB
C++
286 lines
10 KiB
C++
/* Lziprecover - Data recovery tool for the lzip format
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Copyright (C) 2009-2017 Antonio Diaz Diaz.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#define _FILE_OFFSET_BITS 64
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#include <algorithm>
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#include <cerrno>
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#include <cstdio>
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#include <cstring>
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#include <string>
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#include <vector>
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#include <stdint.h>
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#include <unistd.h>
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#include "lzip.h"
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#include "block.h"
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#include "file_index.h"
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int seek_read( const int fd, uint8_t * const buf, const int size,
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const long long pos )
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{
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if( lseek( fd, pos, SEEK_SET ) == pos )
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return readblock( fd, buf, size );
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return 0;
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}
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void File_index::set_errno_error( const char * const msg )
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{
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error_ = msg; error_ += std::strerror( errno );
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retval_ = 1;
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}
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void File_index::set_num_error( const char * const msg, unsigned long long num )
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{
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char buf[80];
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snprintf( buf, sizeof buf, "%s%llu", msg, num );
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error_ = buf;
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retval_ = 2;
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}
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// If successful, push last member and set pos to member header.
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bool File_index::skip_trailing_data( const int fd, const bool ignore_bad_ds,
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long long & pos )
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{
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enum { block_size = 16384,
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buffer_size = block_size + File_trailer::size - 1 + File_header::size };
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uint8_t buffer[buffer_size];
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if( pos < min_member_size ) return false;
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int bsize = pos % block_size; // total bytes in buffer
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if( bsize <= buffer_size - block_size ) bsize += block_size;
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int search_size = bsize; // bytes to search for trailer
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int rd_size = bsize; // bytes to read from file
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unsigned long long ipos = pos - rd_size; // aligned to block_size
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while( true )
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{
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if( seek_read( fd, buffer, rd_size, ipos ) != rd_size )
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{ set_errno_error( "Error seeking member trailer: " ); return false; }
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const uint8_t max_msb = ( ipos + search_size ) >> 56;
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for( int i = search_size; i >= File_trailer::size; --i )
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if( buffer[i-1] <= max_msb ) // most significant byte of member_size
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{
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File_trailer & trailer =
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*(File_trailer *)( buffer + i - File_trailer::size );
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const unsigned long long member_size = trailer.member_size();
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if( member_size == 0 )
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{ while( i > File_trailer::size && buffer[i-9] == 0 ) --i; continue; }
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if( member_size < min_member_size || member_size > ipos + i )
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continue;
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File_header header;
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if( seek_read( fd, header.data, File_header::size,
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ipos + i - member_size ) != File_header::size )
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{ set_errno_error( "Error reading member header: " ); return false; }
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const unsigned dictionary_size = header.dictionary_size();
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if( !header.verify_magic() || !header.verify_version() ||
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( !ignore_bad_ds && !isvalid_ds( dictionary_size ) ) ) continue;
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if( (*(File_header *)( buffer + i )).verify_prefix( bsize - i ) )
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{
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error_ = "Last member in input file is truncated or corrupt.";
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retval_ = 2; return false;
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}
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pos = ipos + i - member_size;
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member_vector.push_back( Member( 0, trailer.data_size(), pos,
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member_size, dictionary_size ) );
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return true;
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}
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if( ipos <= 0 )
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{ set_num_error( "Member size in trailer is corrupt at pos ", pos - 8 );
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return false; }
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bsize = buffer_size;
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search_size = bsize - File_header::size;
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rd_size = block_size;
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ipos -= rd_size;
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std::memcpy( buffer + rd_size, buffer, buffer_size - rd_size );
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}
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}
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File_index::File_index( const int infd, const bool ignore_bad_ds,
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const bool ignore_trailing )
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: isize( lseek( infd, 0, SEEK_END ) ), retval_( 0 )
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{
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if( isize < 0 )
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{ set_errno_error( "Input file is not seekable: " ); return; }
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if( isize < min_member_size )
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{ error_ = "Input file is too short."; retval_ = 2; return; }
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if( isize > INT64_MAX )
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{ error_ = "Input file is too long (2^63 bytes or more).";
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retval_ = 2; return; }
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File_header header;
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if( seek_read( infd, header.data, File_header::size, 0 ) != File_header::size )
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{ set_errno_error( "Error reading member header: " ); return; }
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if( !header.verify_magic() )
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{ error_ = bad_magic_msg; retval_ = 2; return; }
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if( !header.verify_version() )
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{ error_ = bad_version( header.version() ); retval_ = 2; return; }
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if( !ignore_bad_ds && !isvalid_ds( header.dictionary_size() ) )
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{ error_ = bad_dict_msg; retval_ = 2; return; }
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long long pos = isize; // always points to a header or to EOF
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while( pos >= min_member_size )
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{
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File_trailer trailer;
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if( seek_read( infd, trailer.data, File_trailer::size,
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pos - File_trailer::size ) != File_trailer::size )
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{ set_errno_error( "Error reading member trailer: " ); break; }
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const unsigned long long member_size = trailer.member_size();
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if( member_size < min_member_size || member_size > (unsigned long long)pos )
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{
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if( !member_vector.empty() )
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set_num_error( "Member size in trailer is corrupt at pos ", pos - 8 );
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else if( skip_trailing_data( infd, ignore_bad_ds, pos ) )
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{ if( ignore_trailing ) continue;
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error_ = trailing_msg; retval_ = 2; return; }
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break;
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}
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if( seek_read( infd, header.data, File_header::size,
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pos - member_size ) != File_header::size )
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{ set_errno_error( "Error reading member header: " ); break; }
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const unsigned dictionary_size = header.dictionary_size();
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if( !header.verify_magic() || !header.verify_version() ||
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( !ignore_bad_ds && !isvalid_ds( dictionary_size ) ) )
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{
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if( !member_vector.empty() )
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set_num_error( "Bad header at pos ", pos - member_size );
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else if( skip_trailing_data( infd, ignore_bad_ds, pos ) )
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{ if( ignore_trailing ) continue;
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error_ = trailing_msg; retval_ = 2; return; }
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break;
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}
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pos -= member_size;
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member_vector.push_back( Member( 0, trailer.data_size(), pos,
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member_size, dictionary_size ) );
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}
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if( pos != 0 || member_vector.empty() )
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{
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member_vector.clear();
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if( retval_ == 0 ) { error_ = "Can't create file index."; retval_ = 2; }
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return;
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}
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std::reverse( member_vector.begin(), member_vector.end() );
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for( unsigned long i = 0; i < member_vector.size() - 1; ++i )
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{
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const long long end = member_vector[i].dblock.end();
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if( end < 0 || end > INT64_MAX )
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{
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member_vector.clear();
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error_ = "Data in input file is too long (2^63 bytes or more).";
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retval_ = 2; return;
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}
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member_vector[i+1].dblock.pos( end );
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}
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}
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// All files in 'infd_vector' must be at least 'fsize' bytes long.
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File_index::File_index( const std::vector< int > & infd_vector,
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const long long fsize )
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: isize( fsize ), retval_( 0 )
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{
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if( isize < 0 )
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{ set_errno_error( "Input file is not seekable: " ); return; }
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if( isize < min_member_size )
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{ error_ = "Input file is too short."; retval_ = 2; return; }
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if( isize > INT64_MAX )
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{ error_ = "Input file is too long (2^63 bytes or more).";
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retval_ = 2; return; }
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const int files = infd_vector.size();
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File_header header;
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bool done = false;
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for( int i = 0; i < files && !done; ++i )
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{
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const int infd = infd_vector[i];
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if( seek_read( infd, header.data, File_header::size, 0 ) != File_header::size )
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{ set_errno_error( "Error reading member header: " ); return; }
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if( header.verify_magic() && header.verify_version() ) done = true;
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}
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if( !done )
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{ error_ = bad_magic_msg; retval_ = 2; return; }
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long long pos = isize; // always points to a header or to EOF
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while( pos >= min_member_size )
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{
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unsigned long long member_size;
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File_trailer trailer;
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done = false;
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for( int it = 0; it < files && !done; ++it )
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{
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const int tfd = infd_vector[it];
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if( seek_read( tfd, trailer.data, File_trailer::size,
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pos - File_trailer::size ) != File_trailer::size )
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{ set_errno_error( "Error reading member trailer: " ); goto error; }
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member_size = trailer.member_size();
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if( member_size >= min_member_size && member_size <= (unsigned long long)pos )
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for( int ih = 0; ih < files && !done; ++ih )
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{
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const int hfd = infd_vector[ih];
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if( seek_read( hfd, header.data, File_header::size,
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pos - member_size ) != File_header::size )
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{ set_errno_error( "Error reading member header: " ); goto error; }
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if( header.verify_magic() && header.verify_version() ) done = true;
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}
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}
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if( !done )
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{
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if( member_vector.empty() ) { --pos; continue; } // maybe trailing data
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set_num_error( "Member size in trailer may be corrupt at pos ", pos - 8 );
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break;
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}
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if( member_vector.empty() && isize > pos )
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{
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const int size = std::min( (long long)File_header::size, isize - pos );
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for( int i = 0; i < files; ++i )
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{
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const int infd = infd_vector[i];
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if( seek_read( infd, header.data, size, pos ) == size &&
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header.verify_prefix( size ) )
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{
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error_ = "Last member in input file is truncated or corrupt.";
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retval_ = 2; goto error;
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}
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}
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}
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pos -= member_size;
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member_vector.push_back( Member( 0, trailer.data_size(),
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pos, member_size, 0 ) );
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}
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error:
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if( pos != 0 || member_vector.empty() )
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{
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member_vector.clear();
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if( retval_ == 0 ) { error_ = "Can't create file index."; retval_ = 2; }
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return;
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}
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std::reverse( member_vector.begin(), member_vector.end() );
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for( unsigned long i = 0; i < member_vector.size() - 1; ++i )
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{
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const long long end = member_vector[i].dblock.end();
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if( end < 0 || end > INT64_MAX )
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{
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member_vector.clear();
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error_ = "Data in input file is too long (2^63 bytes or more).";
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retval_ = 2; return;
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}
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member_vector[i+1].dblock.pos( end );
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}
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}
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