#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include<linux/sched.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/slab.h>
#include <linux/delay.h>

#define PROC_FILE_NAME "cat_trap"

#define CAT_TRAP_DISABLED 0
#define CAT_TRAP_ANIMATED 1
#define CAT_TRAP_KERNEL 2
char status = CAT_TRAP_DISABLED;
char animation_chars[] = "-\\|/-\\|/";
int a_place = 0;
char a_backspace = 0;

ssize_t read_simple(struct file *filp, char *buf, size_t count, loff_t *offp ) 
{
	ssize_t ctu_result;
	if(status == CAT_TRAP_DISABLED)
		return 0;
	while(status == CAT_TRAP_KERNEL)
		ssleep(1);

	if(a_backspace){
		ctu_result = copy_to_user(buf, "\b", 1);
		a_backspace = 0;	
	} else {
		ctu_result = copy_to_user(buf, animation_chars + a_place, 1);
		a_place++;
		if(a_place > 8)
			a_place = 0;
		a_backspace = 1;
		msleep(100);
	}
	return 1;
}

ssize_t write_simple(struct file *filp,const char *buf,size_t count,loff_t *offp)
{
	printk("Received command:  %s", buf);
	if(!strncmp(buf, "enable_a", 8))
		status = CAT_TRAP_ANIMATED;
	if(!strncmp(buf, "enable_k", 8))
		status = CAT_TRAP_KERNEL;
	if(!strncmp(buf, "disable", 7))
		status = CAT_TRAP_DISABLED;
	return count;	
}

struct proc_ops proc_fops = {
	proc_read: read_simple,
	proc_write: write_simple
};

int proc_init (void) {
	printk("We're in the kernel!\n");
	// Second argument is a umode_t that is the file permissions
	// 0 give the default, not an actual 0
	proc_create(PROC_FILE_NAME,0666,NULL,&proc_fops);
	return 0;
}

void proc_cleanup(void) {
	remove_proc_entry(PROC_FILE_NAME,NULL);
}

MODULE_LICENSE("GPL"); 
module_init(proc_init);
module_exit(proc_cleanup);