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#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <strings.h>
#include <stdio.h>
#include <fcntl.h>
int main( int args, char **argv )
{
int toindex;
int i, run = 1, filenum = 0, offset = 0, oldoffset = -1;
struct stat fstatus;
unsigned char *mappedfile;
if( args != 2 )
{ fputs( "Missing filenames.", stderr ); exit( 1 ); }
if( ( toindex = open( argv[1], O_RDONLY ) ) < 0 )
{ fprintf( stderr, "Can't open file: %s.\n", argv[1] ); exit( toindex ); }
fstat( toindex, &fstatus );
printf( "Size of file: %d\n", fstatus.st_size );
if( ( mappedfile = mmap( NULL, (size_t)fstatus.st_size, PROT_READ | PROT_WRITE, MAP_NOCORE | MAP_PRIVATE, toindex, 0) ) == MAP_FAILED )
{ fprintf( stderr, "Can't mmap file: %s.", argv[1] ); exit( 1 ); }
while( run )
{
while( ( offset < fstatus.st_size ) && (
( mappedfile[ offset + 0 ] != 0xd9 ) ||
( mappedfile[ offset + 2 ] != 0x6f ) ||
( mappedfile[ offset + 3 ] != 0x6d ) ||
( mappedfile[ offset + 4 ] != 0xaa ) ||
( mappedfile[ offset + 5 ] != 0x11 ) ||
( mappedfile[ offset + 6 ] != 0x6f )
) ) offset++;
printf( "Found an appropriate offset at: %d\n", oldoffset );
if( offset == fstatus.st_size )
run = 0;
if( oldoffset != -1 )
{
unsigned long *mf = (unsigned long*)(mappedfile + oldoffset);
unsigned char filename[20], cs = 0;
for( i=0; i<8; ++i)
mf[i]^=0x014224c2;
snprintf( filename, sizeof( filename ), "%05d.lha", filenum++ );
memcpy( ((unsigned char*)mf) + 22, filename, 5);
for( i=2; i<29; ++i)
cs += ((unsigned char*)mf)[i];
((unsigned char*)mf)[1] = cs;
i = open( filename, O_CREAT | O_TRUNC | O_WRONLY, 0644 );
write( i, mf, offset - oldoffset );
close( i );
}
oldoffset = offset;
offset++;
}
return 0;
}
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