//-------------------------------------------------------------------
//	dumptcb.cpp
//
//	This program shows the contects of its own 'task_struct' in
//	hexadecimal format (if executed with sufficient privilege). 
//	It presumes our 'tcb.o' module is in the current directory.
//
//	programmer: ALLAN CRUSE
//	written on: 18 SEP 2004
//-------------------------------------------------------------------

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

char filename[] = "/proc/tcb";

int main( int argc, char **argv )
{
	// install module that creates the pseudo-file
	int	retval = system( "/sbin/insmod tcb.o" );
       	if ( retval < 0 ) { perror( "system" ); exit(1); }
	
	// open the file
	int	fd = open( filename, O_RDONLY );
	if ( fd < 0 ) { perror( filename ); exit(1); }

	// get file's length (then reposition file's pointer)
	int	filesize = lseek( fd, 0, SEEK_END );
	lseek( fd, 0, SEEK_SET );	// rewind the file
	
	// allocate storage for the file's contents
	char	*buffer = (char*)malloc( filesize );
	if ( buffer == NULL ) { perror( "malloc" ); exit(1); }
	
	// read the current contents of the pseudo-file
	int	nbytes = read( fd, buffer, filesize );
	printf( "\nread %d bytes from \'%s\' \n", nbytes, filename );
	
	// display the 'task_struct' in hexadecimal format
	unsigned long	*lp = (unsigned long*)buffer;
	for (int i = 0; i < nbytes/4; i++)
		{
		if ( ( i % 8 ) == 0 ) printf( "\n%03X: ", i<<2 );
		printf( "%08X ", lp[i] );
		}
	printf( "\n\n" );

	// release storage, close file, and remove the module
	free( buffer );
	close( fd );
	system( "/sbin/rmmod tcb");
}