//-------------------------------------------------------------------
//	kthreads.c		     
//
//	This module creates a pseudo-file (named '/proc/kthreads') 
//	which shows the name and process-ID of each kernel thread.
//	(It is one possible solution to question 5 on Midterm II.)
//
//	programmer: ALLAN CRUSE
//	written on: 14 NOV 2004
//-------------------------------------------------------------------

#include <linux/module.h>	// for init_module() 
#include <linux/proc_fs.h>	// for create_proc_info_entry() 

static char modname[] = "kthreads";

static int my_get_info( char *buf, char **start, off_t off, int count )
{
	struct task_struct	*tsk = &init_task;
	unsigned long		kthreads = 0;
	int			len;
	
	len = 0;
	len += sprintf( buf+len, "\nList of kernel threads\n" );

	do	{
		if ( tsk->mm == 0 ) 	// task is a kernel thread?
			{
			++kthreads;
			len += sprintf( buf+len, "#%-2d ", kthreads );
			len += sprintf( buf+len, "%15s ", tsk->comm );
			len += sprintf( buf+len, "pid=%-5d \n", tsk->pid );
			}
		tsk = tsk->next_task;
		}
	while ( tsk != &init_task );
		
	len += sprintf( buf+len, "\n" );
	return	len;
}


int init_module( void )
{
	printk( "<1>\nInstalling \'%s\' module\n", modname );
	create_proc_info_entry( modname, 0, NULL, my_get_info );
	return	0;  //SUCCESS
}


void cleanup_module( void )
{
	remove_proc_entry( modname, NULL );
	printk( "<1>Removing \'%s\' module\n", modname );
}

MODULE_LICENSE("GPL");