/* Lziprecover - Data recovery tool for the lzip format
Copyright (C) 2009-2019 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 <algorithm>
#include <cerrno>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <stdint.h>
#include <unistd.h>
#include "lzip.h"
#include "lzip_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;
}
void Lzip_index::set_errno_error( const char * const msg )
{
error_ = msg; error_ += std::strerror( errno );
retval_ = 1;
}
void Lzip_index::set_num_error( const char * const msg, unsigned long long num )
{
char buf[80];
snprintf( buf, sizeof buf, "%s%llu", msg, num );
error_ = buf;
retval_ = 2;
}
/* Skip backwards the gap or trailing data ending at pos.
'ignore_gaps' also ignores format errors and a truncated last member.
If successful, push member preceding gap and set pos to member header. */
bool Lzip_index::skip_gap( const int fd, long long & pos,
const bool ignore_trailing, const bool loose_trailing,
const bool ignore_bad_ds, const bool ignore_gaps )
{
enum { block_size = 16384,
buffer_size = block_size + Lzip_trailer::size - 1 + Lzip_header::size };
uint8_t buffer[buffer_size];
if( pos < min_member_size )
{
if( pos >= 0 && ignore_gaps && !member_vector.empty() )
{ pos = 0; return true; }
return false;
}
int bsize = pos % block_size; // total bytes in buffer
if( bsize <= buffer_size - block_size ) bsize += block_size;
int search_size = bsize; // bytes to search for trailer
int rd_size = bsize; // bytes to read from file
unsigned long long ipos = pos - rd_size; // aligned to block_size
while( true )
{
if( seek_read( fd, buffer, rd_size, ipos ) != rd_size )
{ set_errno_error( "Error seeking member trailer: " ); return false; }
const uint8_t max_msb = ( ipos + search_size ) >> 56;
for( int i = search_size; i >= Lzip_trailer::size; --i )
if( buffer[i-1] <= max_msb ) // most significant byte of member_size
{
const Lzip_trailer & trailer =
*(const Lzip_trailer *)( buffer + i - Lzip_trailer::size );
const unsigned long long member_size = trailer.member_size();
if( member_size == 0 ) // skip trailing zeros
{ while( i > Lzip_trailer::size && buffer[i-9] == 0 ) --i; continue; }
if( member_size > ipos + i || !trailer.verify_consistency() )
continue;
Lzip_header header;
if( seek_read( fd, header.data, Lzip_header::size,
ipos + i - member_size ) != Lzip_header::size )
{ set_errno_error( "Error reading member header: " ); return false; }
const unsigned dictionary_size = header.dictionary_size();
if( !header.verify_magic() || !header.verify_version() ||
( !ignore_bad_ds && !isvalid_ds( dictionary_size ) ) ) continue;
if( member_vector.empty() ) // trailing data or truncated member
{
const Lzip_header & last_header = *(const Lzip_header *)( buffer + i );
if( last_header.verify_prefix( bsize - i ) )
{
if( !ignore_gaps )
{ error_ = "Last member in input file is truncated or corrupt.";
retval_ = 2; return false; }
const unsigned dictionary_size =
( bsize - i >= Lzip_header::size ) ?
last_header.dictionary_size() : 0;
const unsigned long long member_size = pos - ( ipos + i );
pos = ipos + i;
member_vector.push_back( Member( 0, 0, pos,
member_size, dictionary_size ) );
return true;
}
}
if( !ignore_gaps && member_vector.empty() )
{
if( !loose_trailing && bsize - i >= Lzip_header::size &&
(*(const Lzip_header *)( buffer + i )).verify_corrupt() )
{ error_ = corrupt_mm_msg; retval_ = 2; return false; }
if( !ignore_trailing )
{ error_ = trailing_msg; retval_ = 2; return false; }
}
pos = ipos + i - member_size;
member_vector.push_back( Member( 0, trailer.data_size(), pos,
member_size, dictionary_size ) );
return true;
}
if( ipos <= 0 )
{ if( ignore_gaps && !member_vector.empty() ) { pos = 0; return true; }
set_num_error( "Bad trailer at pos ", pos - Lzip_trailer::size );
return false; }
bsize = buffer_size;
search_size = bsize - Lzip_header::size;
rd_size = block_size;
ipos -= rd_size;
std::memcpy( buffer + rd_size, buffer, buffer_size - rd_size );
}
}
Lzip_index::Lzip_index( const int infd, const bool ignore_trailing,
const bool loose_trailing, const bool ignore_bad_ds,
const bool ignore_gaps, const long long max_pos )
: insize( lseek( infd, 0, SEEK_END ) ), retval_( 0 )
{
if( insize < 0 )
{ set_errno_error( "Input file is not seekable: " ); return; }
if( insize < min_member_size )
{ error_ = "Input file is too short."; retval_ = 2; return; }
if( insize > INT64_MAX )
{ error_ = "Input file is too long (2^63 bytes or more).";
retval_ = 2; return; }
Lzip_header header;
if( seek_read( infd, header.data, Lzip_header::size, 0 ) != Lzip_header::size )
{ set_errno_error( "Error reading member header: " ); return; }
if( !header.verify_magic() )
{ error_ = bad_magic_msg; retval_ = 2; return; }
if( !header.verify_version() )
{ error_ = bad_version( header.version() ); retval_ = 2; return; }
if( !ignore_bad_ds && !isvalid_ds( header.dictionary_size() ) )
{ error_ = bad_dict_msg; retval_ = 2; return; }
// pos always points to a header or to ( EOF || max_pos )
long long pos = ( max_pos > 0 ) ? max_pos : insize;
while( pos >= min_member_size )
{
Lzip_trailer trailer;
if( seek_read( infd, trailer.data, Lzip_trailer::size,
pos - Lzip_trailer::size ) != Lzip_trailer::size )
{ set_errno_error( "Error reading member trailer: " ); break; }
const unsigned long long member_size = trailer.member_size();
if( member_size > (unsigned long long)pos || !trailer.verify_consistency() )
{
if( ignore_gaps || member_vector.empty() )
{ if( skip_gap( infd, pos, ignore_trailing, loose_trailing,
ignore_bad_ds, ignore_gaps ) ) continue; else return; }
set_num_error( "Bad trailer at pos ", pos - Lzip_trailer::size );
break;
}
if( seek_read( infd, header.data, Lzip_header::size,
pos - member_size ) != Lzip_header::size )
{ set_errno_error( "Error reading member header: " ); break; }
const unsigned dictionary_size = header.dictionary_size();
if( !header.verify_magic() || !header.verify_version() ||
( !ignore_bad_ds && !isvalid_ds( dictionary_size ) ) )
{
if( ignore_gaps || member_vector.empty() )
{ if( skip_gap( infd, pos, ignore_trailing, loose_trailing,
ignore_bad_ds, ignore_gaps ) ) continue; else return; }
set_num_error( "Bad header at pos ", pos - member_size );
break;
}
pos -= member_size;
member_vector.push_back( Member( 0, trailer.data_size(), pos,
member_size, dictionary_size ) );
}
if( pos < 0 || pos >= min_member_size || ( pos != 0 && !ignore_gaps ) ||
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 )
{
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;
}
if( i + 1 >= member_vector.size() ) break;
member_vector[i+1].dblock.pos( end );
}
}
// All files in 'infd_vector' must be at least 'fsize' bytes long.
Lzip_index::Lzip_index( const std::vector< int > & infd_vector,
const long long fsize )
: insize( fsize ), retval_( 0 )
{
if( insize < 0 )
{ set_errno_error( "Input file is not seekable: " ); return; }
if( insize < min_member_size )
{ error_ = "Input file is too short."; retval_ = 2; return; }
if( insize > INT64_MAX )
{ error_ = "Input file is too long (2^63 bytes or more).";
retval_ = 2; return; }
const int files = infd_vector.size();
Lzip_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, Lzip_header::size, 0 ) != Lzip_header::size )
{ set_errno_error( "Error reading member header: " ); return; }
if( header.verify_magic() && header.verify_version() ) done = true;
}
if( !done )
{ error_ = bad_magic_msg; retval_ = 2; return; }
long long pos = insize; // always points to a header or to EOF
while( pos >= min_member_size )
{
unsigned long long member_size;
Lzip_trailer trailer;
done = false;
for( int it = 0; it < files && !done; ++it )
{
const int tfd = infd_vector[it];
if( seek_read( tfd, trailer.data, Lzip_trailer::size,
pos - Lzip_trailer::size ) != Lzip_trailer::size )
{ set_errno_error( "Error reading member trailer: " ); goto error; }
member_size = trailer.member_size();
if( member_size <= (unsigned long long)pos && trailer.verify_consistency() )
for( int ih = 0; ih < files && !done; ++ih )
{
const int hfd = infd_vector[ih];
if( seek_read( hfd, header.data, Lzip_header::size,
pos - member_size ) != Lzip_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() ) { --pos; continue; } // maybe trailing data
set_num_error( "Member size in trailer may be corrupt at pos ", pos - 8 );
break;
}
if( member_vector.empty() && insize > pos )
{
const int size = std::min( (long long)Lzip_header::size, insize - pos );
for( int i = 0; i < files; ++i )
{
const int infd = infd_vector[i];
if( seek_read( infd, header.data, size, pos ) == size &&
header.verify_prefix( size ) )
{
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, 0 ) );
}
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 )
{
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;
}
if( i + 1 >= member_vector.size() ) break;
member_vector[i+1].dblock.pos( end );
}
}
// Returns members + gaps [+ trailing data].
long Lzip_index::blocks( const bool count_tdata ) const
{
long n = member_vector.size() + ( count_tdata && cdata_size() < file_size() );
if( member_vector.size() && member_vector[0].mblock.pos() > 0 ) ++n;
for( unsigned long i = 1; i < member_vector.size(); ++i )
if( member_vector[i].mblock.pos() > member_vector[i-1].mblock.end() ) ++n;
return n;
}