#include?“l(fā)inux/kernel.h“
#include?“l(fā)inux/module.h“
#include?“l(fā)inux/fs.h“
#include?“l(fā)inux/init.h“
#include?“l(fā)inux/types.h“
#include?“l(fā)inux/errno.h“
#include?“l(fā)inux/uaccess.h“
#include?“l(fā)inux/kdev_t.h“
#define?MAX_SIZE?1024

static?int?my_open（struct?inode?*inode?struct?file?*file）;
static?int?my_release（struct?inode?*inode?struct?file?*file）;
static?ssize_t?my_read（struct?file?*file?char?__user?*user?size_t?t?loff_t?*f）;
static?ssize_t?my_write（struct?file?*file?const?char?__user?*user?size_t?t?loff_t?*f）;

static?char?message[MAX_SIZE]?=?“-------congratulations--------!“;
static?int?device_num?=?0;//設(shè)備號(hào)
static?int?counter?=?0;//計(jì)數(shù)用
static?int?mutex?=?0;//互斥用
static?char*?devName?=?“myDevice“;//設(shè)備名

struct?file_operations?pStruct?=
{?open:my_open?release:my_release?read:my_read?write:my_write?};

/*?注冊(cè)模塊?*/
int?init_module（）
{
	int?ret;
	/*?函數(shù)中第一個(gè)參數(shù)是告訴系統(tǒng)，新注冊(cè)的設(shè)備的主設(shè)備號(hào)由系統(tǒng)分配，
	?*?第二個(gè)參數(shù)是新設(shè)備注冊(cè)時(shí)的設(shè)備名字，
	?*?第三個(gè)參數(shù)是指向file_operations的指針，
	?*?當(dāng)用設(shè)備號(hào)為0創(chuàng)建時(shí)，系統(tǒng)一個(gè)可以用的設(shè)備號(hào)創(chuàng)建模塊?*/
	ret?=?register_chrdev（0?devName?&pStruct）;
	if?（ret?	{
		printk（“regist?failure!\n“）;
		return?-1;
	}
	else
	{
		printk（“the?device?has?been?registered!\n“）;
		device_num?=?ret;
		printk（“<1>the?virtual?device‘s?major?number?%d.\n“?device_num）;
		printk（“<1>Or?you?can?see?it?by?using\n“）;
		printk（“<1>------more?/proc/devices-------\n“）;
		printk（“<1>To?talk?to?the?drivercreate?a?dev?file?with\n“）;
		printk（“<1>------‘mknod?/dev/myDevice?c?%d?0‘-------\n“?device_num）;
		printk（“<1>Use?\“rmmode\“?to?remove?the?module\n“）;

		return?0;
	}
}
/*?注銷模塊，函數(shù)名很特殊?*/
void?cleanup_module（）
{
	unregister_chrdev（device_num?devName）;
	printk（“unregister?it?success!\n“）;
}

static?int?my_open（struct?inode?*inode?struct?file?*file）
{
????????if（mutex）
????????????????return?-EBUSY;
????????mutex?=?1;//上鎖
	printk（“<1>main??device?:?%d\n“?MAJOR（inode->i_rdev））;
	printk（“<1>slave?device?:?%d\n“?MINOR（inode->i_rdev））;
	printk（“<1>%d?times?to?call?the?device\n“?++counter）;
	try_module_get（THIS_MODULE）;
	return?0;
}
/*?每次使用完后會(huì)release?*/
static?int?my_release（struct?inode?*inode?struct?file?*file）
{
	printk（“Device?released!\n“）;
	module_put（THIS_MODULE）;
????????mutex?=?0;//開鎖
	return?0;
}

static?ssize_t?my_read（struct?file?*file?char?__user?*user?size_t?t?loff_t?*f）
{
	if（copy_to_user（usermessagesizeof（message）））
	{
		return?-EFAULT;
	}
	return?sizeof（message）;
}

static?ssize_t?my_write（struct?file?*file?const?char?__user?*user?size_t?t?loff_t?*f）
{
	if（copy_from_user（messageusersizeof（message）））
	{
		return?-EFAULT;
	}
	return?sizeof（message）;
}