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/* Tarlz - Archiver with multimember lzip compression
Copyright (C) 2013-2019 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 <cctype>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <stdint.h>
#include "tarlz.h"
namespace {
unsigned decimal_digits( unsigned long long value )
{
unsigned digits = 1;
while( value >= 10 ) { value /= 10; ++digits; }
return digits;
}
int record_size( const unsigned keyword_size, const unsigned long value_size )
{
// size = ' ' + keyword + '=' + value + '\n'
unsigned long long size = 1 + keyword_size + 1 + value_size + 1;
const unsigned d1 = decimal_digits( size );
size += decimal_digits( d1 + size );
if( size >= INT_MAX ) size = 0; // overflows snprintf size
return size;
}
unsigned long long parse_decimal( const char * const ptr,
const char ** const tailp,
const unsigned long long size )
{
unsigned long long result = 0;
unsigned long long i = 0;
while( i < size && std::isspace( ptr[i] ) ) ++i;
if( !std::isdigit( (unsigned char)ptr[i] ) )
{ if( tailp ) *tailp = ptr; return 0; }
for( ; i < size && std::isdigit( (unsigned char)ptr[i] ); ++i )
{
const unsigned long long prev = result;
result *= 10; result += ptr[i] - '0';
if( result < prev || result > LLONG_MAX ) // overflow
{ if( tailp ) *tailp = ptr; return 0; }
}
if( tailp ) *tailp = ptr + i;
return result;
}
uint32_t parse_record_crc( const char * const ptr )
{
uint32_t crc = 0;
for( int i = 0; i < 8; ++i )
{
crc <<= 4;
if( ptr[i] >= '0' && ptr[i] <= '9' ) crc += ptr[i] - '0';
else if( ptr[i] >= 'A' && ptr[i] <= 'F' ) crc += ptr[i] + 10 - 'A';
else if( ptr[i] >= 'a' && ptr[i] <= 'f' ) crc += ptr[i] + 10 - 'a';
else { crc = 0; break; } // invalid digit in crc string
}
return crc;
}
} // end namespace
const std::string Extended::crc_record( "22 GNU.crc32=00000000\n" );
int Extended::recsize_linkpath() const
{
if( recsize_linkpath_ < 0 ) recsize_linkpath_ =
linkpath_.size() ? record_size( 8, linkpath_.size() ) : 0;
return recsize_linkpath_;
}
int Extended::recsize_path() const
{
if( recsize_path_ < 0 )
recsize_path_ = path_.size() ? record_size( 4, path_.size() ) : 0;
return recsize_path_;
}
int Extended::recsize_file_size() const
{
if( recsize_file_size_ < 0 ) recsize_file_size_ =
( file_size_ > 0 ) ? record_size( 4, file_size_ ) : 0;
return recsize_file_size_;
}
bool Extended::parse( const char * const buf, const unsigned long long edsize,
const bool permissive )
{
reset();
for( unsigned long long pos = 0; pos < edsize; ) // parse records
{
const char * tail;
const unsigned long long rsize =
parse_decimal( buf + pos, &tail, edsize - pos );
if( rsize == 0 || rsize > edsize - pos || tail[0] != ' ' ||
buf[pos+rsize-1] != '\n' ) return false;
++tail; // point to keyword
// rest = length of (keyword + '=' + value) without the final newline
const unsigned long long rest = ( buf + ( pos + rsize - 1 ) ) - tail;
if( rest > 5 && std::memcmp( tail, "path=", 5 ) == 0 )
{ if( path_.size() && !permissive ) return false;
path_.assign( tail + 5, rest - 5 ); }
else if( rest > 9 && std::memcmp( tail, "linkpath=", 9 ) == 0 )
{ if( linkpath_.size() && !permissive ) return false;
linkpath_.assign( tail + 9, rest - 9 ); }
else if( rest > 5 && std::memcmp( tail, "size=", 5 ) == 0 )
{
if( file_size_ != 0 && !permissive ) return false;
file_size_ = parse_decimal( tail + 5, &tail, rest - 5 );
// parse error or size fits in ustar header
if( file_size_ < 1ULL << 33 || tail != buf + ( pos + rsize - 1 ) )
return false;
}
else if( rest > 10 && std::memcmp( tail, "GNU.crc32=", 10 ) == 0 )
{
if( crc_present_ && !permissive ) return false;
if( rsize != crc_record.size() ) return false;
const uint32_t stored_crc = parse_record_crc( tail + 10 );
const uint32_t computed_crc =
crc32c.windowed_crc( (const uint8_t *)buf, pos + rsize - 9, edsize );
crc_present_ = true;
if( stored_crc != computed_crc ) return false;
}
pos += rsize;
}
full_size_ = header_size + round_up( edsize );
return true;
}
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