linux内核异步通知用户空间fasync

#include <linux/module.h> #include <linux/types.h> #include <linux/fs.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/sched.h> #include <linux/init.h> #include <linux/cdev.h> #include <linux/device.h> #include <linux/poll.h> #include <linux/timer.h> #include <asm/io.h> #include <asm/system.h> #include <asm/uaccess.h> #include <asm/atomic.h> struct fasync_device { struct cdev cdev; struct timer_list timer; struct fasync_struct *fasync_queue; }; struct fasync_device fasync_dev; #define FASYNC_MAJOR 250 static int fasync_major = FASYNC_MAJOR; static int fasync_open(struct inode *inode, struct file *file) { printk(KERN_DEBUG "%s\n", __FUNCTION__); return 0; } static int fasync_fun(int fd, struct file *filp, int on) { u32 ret; ret = fasync_helper(fd, filp, on, &fasync_dev.fasync_queue); if (ret < 0) { printk(KERN_ERR "register fasync_helper failed\n"); return ret; } printk(KERN_DEBUG "%s\n", __FUNCTION__); return 0; } static int fasync_release(struct inode *inode, struct file *file) { printk(KERN_DEBUG "%s\n", __FUNCTION__); unregister_chrdev_region(MKDEV(fasync_major, 0), 1); fasync_fun(-1, file, 0); return 0; } static const struct file_operations fasync_ops = { .owner = THIS_MODULE, .open = fasync_open, .release = fasync_release, .fasync = fasync_fun, }; static void timer_function(unsigned long para) { if (&fasync_dev.fasync_queue) { kill_fasync(&fasync_dev.fasync_queue, SIGIO, POLL_IN); printk(KERN_DEBUG "kernel send fasync\n"); } mod_timer(&fasync_dev.timer, jiffies + 2 * HZ); } static int __init fasync_dev_init(void) { u32 ret; dev_t devno = MKDEV(fasync_major, 0); printk(KERN_DEBUG "%s\n", __FUNCTION__); ret = register_chrdev_region(devno, 1, "fasync_dev"); if (ret < 0) { printk(KERN_ERR "register fasync_dev dev resion failed\n"); return ret; } cdev_init(&fasync_dev.cdev, &fasync_ops); fasync_dev.cdev.owner = THIS_MODULE; fasync_dev.cdev.ops = &fasync_ops; ret = cdev_add(&fasync_dev.cdev, devno, 1); if (ret < 0) { printk(KERN_ERR "add fasync_dev failed\n"); goto err0; } printk(KERN_DEBUG "register fasync_dev ok!\n"); init_timer(&fasync_dev.timer); fasync_dev.timer.expires = jiffies + 2 * HZ; fasync_dev.timer.function = timer_function; add_timer(&fasync_dev.timer); printk(KERN_DEBUG "add timer ok!\n"); return 0; err0: unregister_chrdev_region(devno, 1); return -1; } module_init(fasync_dev_init); static void __exit fasync_dev_exit(void) { cdev_del(&fasync_dev.cdev); unregister_chrdev_region(MKDEV(fasync_major, 0), 1); del_timer(&fasync_dev.timer); } module_exit(fasync_dev_exit); MODULE_AUTHOR("lei_wang"); MODULE_LICENSE("GPL");