/*
 *  ioctl test module -- Rich West.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h> /* error codes */
#include <linux/proc_fs.h>
#include <asm/uaccess.h>
#include <linux/tty.h>
#include <linux/sched.h>

MODULE_LICENSE("GPL");

/* attribute structures */
struct ioctl_test_t {
  int field1;
  char field2;
};

#define IOCTL_TEST _IOW(0, 6, struct ioctl_test_t)

static int pseudo_device_ioctl(struct inode *inode, struct file *file,
			       unsigned int cmd, unsigned long arg);
static int pseudo_device_read(struct file *, char __user *, size_t, loff_t *);

static struct file_operations pseudo_dev_proc_operations;

static struct proc_dir_entry *proc_entry;

static int __init initialization_routine(void) {
  printk("<1> Loading module\n");

  pseudo_dev_proc_operations.ioctl = pseudo_device_ioctl;
  pseudo_dev_proc_operations.read = pseudo_device_read;

  /* Start create proc entry */
  proc_entry = create_proc_entry("ioctl_test", 0444, NULL);
  if(!proc_entry)
  {
    printk("<1> Error creating /proc entry.\n");
    return 1;
  }

  //proc_entry->owner = THIS_MODULE; <-- This is now deprecated
  proc_entry->proc_fops = &pseudo_dev_proc_operations;

  return 0;
}

/* 'printk' version that prints to active tty. */
void my_printk(char *string)
{
  struct tty_struct *my_tty;

  my_tty = current->signal->tty;

  if (my_tty != NULL) {
    (*my_tty->driver->ops->write)(my_tty, string, strlen(string));
    (*my_tty->driver->ops->write)(my_tty, "\015\012", 2);
  }
} 


static void __exit cleanup_routine(void) {

  printk("<1> Dumping module\n");
  remove_proc_entry("ioctl_test", NULL);

  return;
}


/***
 * ioctl() entry point...
 */
static int pseudo_device_ioctl(struct inode *inode, struct file *file,
				unsigned int cmd, unsigned long arg)
{
  struct ioctl_test_t ioc;
  
  switch (cmd){

  case IOCTL_TEST:
    copy_from_user(&ioc, (struct ioctl_test_t *)arg, 
		   sizeof(struct ioctl_test_t));
    printk("<1> ioctl: call to IOCTL_TEST (%d,%c)!\n", 
	   ioc.field1, ioc.field2);

    my_printk ("Got msg in kernel\n");
    break;
  
  default:
    return -EINVAL;
    break;
  }
  
  return 0;
}

/***
 * read() entry point...
 */
static int pseudo_device_read(struct file *file, char __user *buf, size_t size, loff_t *off)
{
	my_printk ("in kernel module read function\n");
	copy_to_user (buf, "hello!!!\0", 9);
	return 0;
}

module_init(initialization_routine); 
module_exit(cleanup_routine);