//-------------------------------------------------------------------
//	sleep.c
//
//	This module creates a pseudo-file (named '/proc/sleep') that
//	an application can read in order to see the current value of 
//	the 'sleep_time' field in each task's task_struct.
//
//	programmer: ALLAN CRUSE
//	written on: 14 SEP 2004
//-------------------------------------------------------------------

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

#define	SUCCESS	0

static char modname[] = "sleep";

static int my_proc_read( char *buf, char **start, off_t off,
			int count, int *eof, void *data )
{
	struct task_struct	*tsk = &init_task;
	int	item, len;
	char	state[ 40 ];
	
	len = item = 0; 
	do 	{
		++item;
		len += sprintf( buf+len, "%5d ", tsk->pid );
		len += sprintf( buf+len, "%10lu ", tsk->sleep_time );
		len += sprintf( buf+len, "%-16s ", tsk->comm );

		switch( tsk->state )
			{
			case TASK_RUNNING: 
				strcpy( state, "TASK_RUNNING" ); 
				break;
			case TASK_INTERRUPTIBLE: 
				strcpy( state, "TASK_INTERRUPTIBLE" ); 
				break;
			case TASK_UNINTERRUPTIBLE: 
				strcpy( state, "TASK_UNINTERRUPTIBLE" ); 
				break;
			case TASK_STOPPED: 
				strcpy( state, "TASK_STOPPED" ); 
				break;
			case TASK_ZOMBIE: 
				strcpy( state, "TASK_ZOMBIE" ); 
				break;
			default: 
				strcpy( state, "(other)" ); 
				break;
			}	 
		len += sprintf( buf+len, "%s ", state );
		
		len += sprintf( buf+len, "\n" );
		tsk = tsk->next_task;
		}
	while ( tsk != &init_task );

	len += sprintf( buf+len, "\njiffies=%lu ", jiffies );
	len += sprintf( buf+len, " number of tasks = %d ", item );	
	len += sprintf( buf+len, "\n" );
	return	len;
}


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


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

MODULE_LICENSE("GPL");