/* YOUR FILE-HEADER COMMENT HERE */

/*
 * This file uses kernel-doc style comments, which is similar to
 * Javadoc and Doxygen-style comments.  See
 * ~/linux/Documentation/kernel-doc-nano-HOWTO.txt for details.
 */

/*
 * Getting compilation warnings?  The Linux kernel is written against
 * C89, which means:
 *  - No // comments, and
 *  - All variables must be declared at the top of functions.
 * Read ~/linux/Documentation/CodingStyle to ensure your project
 * compiles without warnings.
 */

#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <asm/uaccess.h>

#define PREFIX "SCRUBBER: "

/*
 * Read xt_filter.c to learn how to use these two functions.
 */
#define FILTER_IRQ 6
extern void filter_enable(void);
extern void filter_disable(void);
extern void filter_resume(void);
extern char *filter_get_payload(size_t *);

/**
 * scrubber_open() - callback invoked when a process tries to open
 * /dev/scrubber
 * @inode: inode of character device (ignored)
 * @filp: process's file object (ignored)
 *
 * Return: always 0
 */
static int scrubber_open(struct inode *inode, struct file *filp)
{
	return 0;
}

/**
 * scrubber_write() - callback invoked when a process writes to
 * /dev/scrubber
 * @filp: process's file object (ignored)
 * @ubuf: source buffer
 * @count: number of bytes in @ubuf
 * @ppos: file offset (ignored)
 *
 * Copy from @ubuf into a local buffer, the lesser of @count or 80
 * bytes. Tokenize the buffer, splitting on the newline ('\n')
 * character. For each token, add it to an internal list of "dirty
 * words".
 *
 * WARNING: @ubuf is not null-terminated.
 *
 * HINT: strsep() and kstrdup() are useful here.
 *
 * Return: @count on success, negative on error
 */
static ssize_t scrubber_write(struct file *filp, const char __user * ubuf,
			      size_t count, loff_t * ppos)
{
	/* YOUR CODE HERE */
	return count;
}

static const struct file_operations scrubber_fops = {
	.owner = THIS_MODULE,
	.open = scrubber_open,
	.write = scrubber_write
};

static struct miscdevice scrubber_dev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "scrubber",
	.fops = &scrubber_fops,
	.mode = 0222,
};

/**
 * scrubber_init() - entry point into the scubber kernel module
 * Return: 0 on successful initialization, negative on error
 */
static int __init scrubber_init(void)
{
	int retval;

	retval = misc_register(&scrubber_dev);
	if (retval) {
		pr_err(PREFIX "Could not register device\n");
		return -ENODEV;
	}

	filter_enable();
	return 0;
}

/**
 * scrubber_exit() - called by kernel to clean up resources
 */
static void __exit scrubber_exit(void)
{
	filter_disable();
	misc_deregister(&scrubber_dev);
}

module_init(scrubber_init);
module_exit(scrubber_exit);

MODULE_DESCRIPTION("CS421 scrubber driver");
MODULE_LICENSE("GPL");