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/* Xlunzip - Test tool for the lzip_decompress linux module
Copyright (C) 2016-2024 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 <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "linux_lunzip.h"
#include "lzip.h"
/* Return the number of bytes really read.
If (value returned < size) and (errno == 0), means EOF was reached.
*/
static long readblock( const int fd, uint8_t * const buf, const long size )
{
long sz = 0;
errno = 0;
while( sz < size )
{
const int n = read( fd, buf + sz, min( 1L << 20, size - sz ) );
if( n > 0 ) sz += n;
else if( n == 0 ) break; /* EOF */
else if( errno != EINTR ) break;
errno = 0;
}
return sz;
}
/* Return the address of a malloc'd buffer containing the file data and
the buffer and file sizes in '*buffer_sizep' and '*file_sizep'.
In case of error, return 0 and do not modify '*sizep'.
*/
static uint8_t * read_file( const int infd, long * const buffer_sizep,
long * const file_sizep, const char * const filename )
{
long buffer_size = 1 << 20;
uint8_t * buffer = (uint8_t *)malloc( buffer_size );
if( !buffer ) { show_file_error( filename, mem_msg, 0 ); return 0; }
long file_size = readblock( infd, buffer, buffer_size );
while( file_size >= buffer_size && !errno )
{
if( buffer_size >= LONG_MAX )
{ show_file_error( filename, "Input file is too large.", 0 );
free( buffer ); return 0; }
buffer_size = ( buffer_size <= LONG_MAX / 2 ) ? 2 * buffer_size : LONG_MAX;
uint8_t * const tmp = (uint8_t *)realloc( buffer, buffer_size );
if( !tmp )
{ show_file_error( filename, mem_msg, 0 ); free( buffer ); return 0; }
buffer = tmp;
file_size += readblock( infd, buffer + file_size, buffer_size - file_size );
}
if( errno )
{ show_file_error( filename, "Error reading file", errno ); free( buffer );
return 0; }
*buffer_sizep = buffer_size;
*file_sizep = file_size;
return buffer;
}
struct File_sizes
{
unsigned long long csize; /* compressed size */
unsigned long long dsize; /* decompressed size */
unsigned long tsize; /* trailing data size */
long members;
};
static const char * set_file_sizes( struct File_sizes * const file_sizes,
const uint8_t * const buffer,
const unsigned long file_size )
{
if( file_size <= Lh_size ) return "File ends unexpectedly at member header.";
if( file_size < min_member_size ) return "Input file is too short.";
const Lzip_header * header = (const Lzip_header *)buffer;
if( !Lh_check_magic( *header ) )
return "Bad magic number (file not in lzip format).";
if( !Lh_check_version( *header ) )
return "Version of lzip member format not supported.";
file_sizes->csize = file_sizes->dsize = file_sizes->tsize = 0;
file_sizes->members = 0;
unsigned long pos = file_size; /* always points to a header or to EOF */
while( pos >= min_member_size )
{
const Lzip_trailer * const trailer =
(const Lzip_trailer *)( buffer + pos - Lt_size );
const unsigned long long member_size = Lt_get_member_size( *trailer );
if( member_size < min_member_size || member_size > pos )
{
if( file_sizes->csize == 0 ) /* maybe trailing data */
{
if( member_size == 0 ) /* skip trailing zeros */
while( pos > Lt_size && buffer[pos-8] == 0 ) --pos;
else --pos;
continue;
}
return "Member size in trailer is corrupt.";
}
header = (const Lzip_header *)( buffer + pos - member_size );
if( !Lh_check_magic( *header ) || !Lh_check_version( *header ) )
{
if( file_sizes->csize == 0 ) { --pos; continue; } /* maybe trailing data */
return "Bad member header inside file.";
}
if( file_sizes->csize == 0 && file_size - pos > 0 )
{
file_sizes->tsize = file_size - pos;
header = (const Lzip_header *)( buffer + pos );
if( file_size - pos > Lh_size &&
Lh_check_magic( *header ) && Lh_check_version( *header ) )
return "Last member in input file is truncated or corrupt.";
}
pos -= member_size;
file_sizes->csize += member_size;
file_sizes->dsize += Lt_get_data_size( *trailer );
++file_sizes->members;
}
if( pos != 0 || file_sizes->csize == 0 ) return "Can't get file sizes.";
if( file_sizes->csize + file_sizes->tsize != file_size )
return "Error getting file sizes.";
if( file_sizes->csize > LONG_MAX ) return "File is larger than LONG_MAX.";
if( file_sizes->dsize > LONG_MAX ) return "Data is larger than LONG_MAX.";
return 0;
}
static const char * global_name; /* copy of filename for 'error' */
static void error(char *x) { show_file_error( global_name, x, 0 ); }
/*
* Load the compressed file at the end of the buffer used to hold the
* decompressed data. Check that the in-place decompression does not
* overwrite the compressed data. The buffer must be large enough to contain
* after the decompressed data extra space for a marker, a trailer, the
* maximum possible data expansion, and (if multimember) N-1 empty members.
*
* |------ compressed data ------|
* V V
* |----------------|-------------------|---------|
* ^ ^ extra
* |-------- decompressed data ---------|
*/
int decompress_in_place( const int infd, struct Pretty_print * const pp,
const bool testing )
{
long buffer_size = 0, file_size = 0;
uint8_t * buffer = read_file( infd, &buffer_size, &file_size, pp->name );
if( !buffer ) return 1;
struct File_sizes file_sizes;
const char * emsg = set_file_sizes( &file_sizes, buffer, file_size );
if( emsg ) { show_file_error( pp->name, emsg, 0 ); return 2; }
const long csize = file_sizes.csize;
const long dsize = file_sizes.dsize;
/* const long extra_bytes = ( dsize >> 8 ) + 65536; wrong linux formula */
const long extra_bytes = ( csize >> 6 ) + file_sizes.members * min_member_size;
const long long target_buffer_size = max( dsize, csize ) + extra_bytes;
if( target_buffer_size > LONG_MAX )
{ show_file_error( pp->name, "Buffer is larger than LONG_MAX.", 0 );
return 1; }
if( buffer_size < target_buffer_size ) /* avoid realloc if big enough */
{
buffer = (uint8_t *)realloc( buffer, target_buffer_size );
if( !buffer ) { show_file_error( pp->name, mem_msg, 0 ); return 1; }
}
buffer_size = target_buffer_size;
const long cbegin = buffer_size - csize; /* overwrite trailing data */
if( cbegin > 0 ) memmove( buffer + cbegin, buffer, csize );
long in_pos, out_pos;
int retval;
global_name = pp->name;
retval = convert_retval( __lunzip( buffer + cbegin, csize, 0, 0, buffer,
buffer_size, &in_pos, &out_pos, error ) );
if( retval == 0 && !testing )
{
const long len = flush( buffer, out_pos );
if( len < out_pos )
{ show_file_error( pp->name, "Write error", errno ); return 1; }
}
free( buffer );
if( retval ) return retval;
show_results( pp, in_pos, out_pos, testing );
return 0;
}
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