//----------------------------------------------------------------
//	showpagedir.cpp
//
//	This program opens the pseudo-file created by the 'gpd.c'
//	module, reads the current Global Page Directory, and then
//	displays its directory-entries using hexadecimal format.  
//
//	NOTE: written and tested with Linux kernel version 2.4.20.
//
//	programmer: ALLAN CRUSE
//	written on: 20 FEB 2003
//----------------------------------------------------------------


#include <stdio.h>	// for printf(), perror()
#include <fcntl.h>	// for open(), O_RDONLY
#include <unistd.h>	// for read(), close()
#include <stdlib.h>	// for exit()

#define FILENAME "/proc/gpd"

int main( void )
{
	int	fd = open( FILENAME, O_RDONLY );
	if ( fd < 0 ) { perror( "open" ); exit(1); }

	unsigned long	pgdir[ 4096 ] = {0};
	int	nbytes = read( fd, pgdir, 4096 );
	if ( nbytes < 4096 ) { perror( "read" ); exit(1); }

	printf( "\n\nThe current Global Page Directory appears below:\n" );
	for (int i = 0; i < 1024; i++)
		{
		if ( ( i % 256 ) == 0 ) printf( "\n" );
		if ( ( i % 8 ) == 0 ) printf( "\n%03X: ", i << 2 );
		printf( "%08X ", pgdir[ i ] );
		}	
	printf( "\n\n" );
	close( fd );
}