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#include <asm/uaccess.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kdev_t.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/errno.h>
static char devname[] = "pidevice";
static char modname[] = "pidevice.ko";
static dev_t mydev = 0;
static struct cdev cdev;
static int count = 1;
int pidev_open(struct inode *i, struct file *filp)
{
count = 1;
printk(KERN_ALERT "pidev_open: device (%d-%d) opened\n",
imajor(i), iminor(i));
printk(KERN_ALERT "pidev_open: mode %c%c\n", filp->f_mode & FMODE_READ ? 'R' : '-',
filp->f_mode & FMODE_WRITE ? 'W' : '-');
return 0;
}
ssize_t pidev_read(struct file *filp, char __user *buf,
size_t len, loff_t *off)
{
if (count--) {
if (copy_to_user(buf, modname, 12))
printk(KERN_ALERT "pidev_read: error reading from (__user) %p\n", buf);
return 12;
} else {
return 0;
}
}
ssize_t pidev_write(struct file *filp, const char __user *buf,
size_t len, loff_t *off)
{
char localbuf[40];
if (copy_from_user(localbuf, buf, 40))
printk(KERN_ALERT "pidev_write: error writing in (__user) %p\n", buf);
localbuf[len] = '\0';
printk(KERN_ALERT "pidev_write: received: %s", localbuf);
return -EPERM;
}
long pidev_ioctl(struct file *filp, unsigned msg, unsigned long param)
{
printk(KERN_ALERT "pidev_ioctl: received msg %d / param %ld\n", msg, param);
return 0;
}
struct file_operations fops = {
.owner = THIS_MODULE,
.open = pidev_open,
.read = pidev_read,
.write = pidev_write,
.unlocked_ioctl = pidev_ioctl,
};
static int __init pidev_init(void)
{
int err;
printk(KERN_ALERT "pidev_init: %s loaded by %s (%d)\n",
modname, current->comm, current->pid);
if ((err = alloc_chrdev_region(&mydev, 0, 1, devname)))
printk(KERN_ALERT "pidev_init: error %d in alloc_chrdev_region\n", err);
else
printk(KERN_ALERT "pidev_init: %s successfully registered with"
"%d %d numbers\n", devname, MAJOR(mydev), MINOR(mydev));
cdev_init(&cdev, &fops);
cdev.owner = THIS_MODULE;
if ((err = cdev_add(&cdev, mydev, 1)))
printk(KERN_ALERT "pidev_init: error %d in cdev_add\n", err);
return 0;
}
static void __exit pidev_exit(void)
{
unregister_chrdev_region(mydev, 1);
cdev_del(&cdev);
printk(KERN_ALERT "pidev_exit: %s unloaded\n", modname);
}
module_init(pidev_init);
module_exit(pidev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Guillermo Ramos");
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