//-------------------------------------------------------------------
//	forkfb.cpp
//
//	This program tests page-directory inheritance.
//
//	programmer: ALLAN CRUSE
//	written on: 29 APR 2003
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open() 
#include <stdlib.h>	// for exit() 
#include <unistd.h>	// for read(), write(), close() 
#include <sys/mman.h>	// for mmap(), munmap()
#include <sys/wait.h>	// for wait()

#define HRES 1280
#define VRES 1024

char filename[] = "/dev/vram";
long *vram = (long*)0x10000000;

int main( int argc, char **argv )
{
	// open the device file
	int	mm = open( filename, O_RDWR );
	if ( mm < 0 ) { perror( filename ); exit(1); }
	int	vramsize = lseek( mm, 0, SEEK_END );

	int	prot = ( PROT_READ | PROT_WRITE );
	int	flags = MAP_SHARED;
	vram = (long*)mmap( 0, vramsize, prot, flags, mm, 0 );
	printf( "\nMapped %d-MB video frame-buffer ", vramsize >> 20 );
	printf( "to user-address %08X \n", vram );

	int	pid = fork();
	if ( pid == 0 ) // child process
		{
		int	color = 0x00FF00FF;
		int	i;
		for (i = 0; i < 10*HRES; i++) vram[i] = color;
		exit(0);
		}
	
	int	status;
	wait( &status );

	int	color = 0x00777777;
	int	j = 10*HRES;
	int	i;
	for (i = 0; i < 10*HRES; i++) vram[i+j ] = color;
		
	printf( "\nChild process (pid=%d) has terminated\n", pid );
	munmap( vram, vramsize );
	close( mm );
}