#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/slab.h>
-#include <asm/uaccess.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
MODULE_LICENSE("GPL");
-#define MAXLEN 4000
static dev_t devnum;
static struct cdev *dev;
-static const char default_greeting[] = "Hello, World!\n";
+static const char def_greeting[] = "Hello, World!\n";
-struct hello_buffer {
- size_t len;
- char buffer[0];
-};
-struct hello_buffer *hello;
+static DEFINE_SPINLOCK(hello_lock);
static int hello_open(struct inode *ino, struct file *fp)
{
return 0;
}
+static void hello_world(unsigned long greeting)
+{
+ printk(KERN_INFO "%s", (char *) greeting);
+}
+
+static DEFINE_TIMER(hello_timer, hello_world, 0, def_greeting);
+
static ssize_t hello_read(struct file *fp, char __user *buf, size_t sz,
loff_t *pos)
{
- int r;
- if (sz + *pos > hello->len)
- sz = hello->len - *pos;
- r = copy_to_user(buf, hello->buffer + *pos, sz);
- if (r)
- return -EFAULT;
- *pos += sz;
- return sz;
+ printk(KERN_INFO "Adding timer...\n");
+ hello_timer.expires = jiffies + 5 * HZ;
+ add_timer(&hello_timer);
+ return 0;
}
static ssize_t hello_write(struct file *fp, const char __user *buf, size_t sz,
loff_t *pos)
{
- int r;
- if (sz + *pos > MAXLEN)
- sz = MAXLEN - *pos;
- r = copy_from_user(hello->buffer + *pos, buf, sz);
- if (r)
- return -EFAULT;
- *pos += sz;
- if (hello->len < *pos)
- hello->len = *pos;
- return sz;
+ return 0;
}
static int hello_release(struct inode *ino, struct file *fp)
static int __init ch_init(void)
{
int r = 0;
- hello = kzalloc(sizeof(*hello) + MAXLEN, GFP_KERNEL);
- if (!hello) {
- r = -ENOMEM;
- goto out;
- }
- memcpy(hello->buffer, default_greeting, sizeof(default_greeting));
- hello->len = sizeof(default_greeting);
r = alloc_chrdev_region(&devnum, 0, 256, "hello");
if (r)
goto reg_out;
cdev_out:
unregister_chrdev_region(devnum, 256);
reg_out:
- kfree(hello);
-out:
return r;
}
static void __exit ch_exit(void)
{
+ del_timer_sync(&hello_timer);
cdev_del(dev);
unregister_chrdev_region(devnum, 256);
- kfree(hello);
}
module_init(ch_init);