//-------------------------------------------------------------------
//	smiload.cpp
//
//	This program loads copies of a SMI interrupt service routine
//	into prescribed locations in the System Management Memory on
//	our classroom workstations, relying on functions provided by
//	our 'smram.c' device-driver which must already be installed.
//	The name of the file containing the ISR in binary executable 
//	format is supplied as a command-line argument.  Students may
//	then use our 'issuesmi.cpp' application-program to trigger a
//	System Management Interrupt, and thereby execute those ISRs.
//
//		to compile:  $ g++ smiload.cpp -o smiload
//		to execute:  $ ./smiload <filename>
//
//
//	NOTE: The system manufacturer's SMI handlers get overwritten
//	by this action, and thus they cease to function until a user
//	reboots the machine.  Students should not neglect to perform
//	a 'cold' reboot when they have finished any experiments they
//	undertake using this application.  (This code is specific to 
//	the system configuration of our classroom's workstations for
//	Fall 2008, and must NOT be executed on any outside machines;
//	it is created solely for our CS 630 "in-class" experiments.)
//
//	NOTE: The four SMI entry-points (hardcoded below) were found
//	by using our 'smlayout.cpp' development utility.  
//
//	programmer: ALLAN CRUSE
//	written on: 09 DEC 2008
//-------------------------------------------------------------------

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

#define MAX_INPUT	4096

#define SMIENTRY0	0x000F8000
#define SMIENTRY1	0x000E8000
#define SMIENTRY2	0x000D8000
#define SMIENTRY3	0x000C8000

char devname[] = "/dev/smram";

int main( int argc, char **argv )
{
	// check for the required command-line argument
	if ( argc == 1 ) 
		{ fprintf( stderr, "No input-file\n" ); exit(1); }
	
	// open the specified input-file for reading
	int	fi = open( argv[1], O_RDONLY );
	if ( fi < 0 ) { perror( argv[1] ); exit(1); }

	// obtain the input-file's size 
	int	filesize = lseek( fi, 0, SEEK_END );
	printf( "\n\'%s\': filesize = 0x%X \n", argv[1], filesize ); 
	if ( filesize > MAX_INPUT )
		{ fprintf( stderr, "input-file too large\n" ); exit(1); } 
	
	// read the contents of the input-file
	char	inbuff[ MAX_INPUT ] = {0};
	lseek( fi, 0, SEEK_SET );
	if ( read( fi, inbuff, sizeof( inbuff ) ) < 0 )
		{ perror( "read" ); exit(1); }

	// open the device-file for reading and writing
	int	fo = open( devname, O_RDWR );
	if ( fo < 0 ) { perror( devname ); exit(1); }

	//---------------------------------------------
	// install copies of the SMI interrupt-handler 
	//---------------------------------------------
	
	lseek( fo, SMIENTRY0, SEEK_SET );
	if ( write( fo, inbuff, filesize ) < 0 )
		{ perror( "write" ); exit(1); }

	lseek( fo, SMIENTRY1, SEEK_SET );
	if ( write( fo, inbuff, filesize ) < 0 )
		{ perror( "write" ); exit(1); }

	lseek( fo, SMIENTRY2, SEEK_SET );
	if ( write( fo, inbuff, filesize ) < 0 )
		{ perror( "write" ); exit(1); }

	lseek( fo, SMIENTRY3, SEEK_SET );
	if ( write( fo, inbuff, filesize ) < 0 )
		{ perror( "write" ); exit(1); }

	close( fo );
}