//-------------------------------------------------------------------
//	maccall.c
//
//	This is one possible solution for Final Exam Question 6.
//
//	programmer: ALLAN CRUSE
//	date begun: 15 MAY 2005
//-------------------------------------------------------------------

#include <linux/module.h>	// for init_module() 
#include <linux/pci.h>		// for pci_find_device()
#include <asm/uaccess.h>	// for copy_to_user()
#include <asm/unistd.h>		// for __NR_break

#define VENDOR_ID	0x10EC
#define DEVICE_ID	0x8139

char modname[] = "maccall";
extern unsigned long *sys_call_table;
unsigned long original_entry;
unsigned char mac[6];

asmlinkage long my_syscall( unsigned char __user * buf )
{
	struct pci_dev	*devp = NULL;
	int	i, iobase;

	devp = pci_find_device( VENDOR_ID, DEVICE_ID, devp );
	if ( !devp ) return -ENODEV;

	iobase = pci_resource_start( devp, 0 );
	for (i = 0; i < 6; i++) mac[i] = inb( iobase + i );

	if ( copy_to_user( buf, mac, 6 ) ) return -EFAULT;	
	return	0;
}


int init_module( void )
{
	printk( "<1>\nInstalling \'%s\' module\n", modname );

	original_entry = sys_call_table[ __NR_break ]; 
	sys_call_table[ __NR_break ] = my_syscall;
	return	0;  // SUCCESS
}


void cleanup_module( void )
{
	sys_call_table[ __NR_break ] = original_entry;
	printk( "<1>Removing \'%s\' module\n", modname );
}

MODULE_LICENSE("GPL");