Linux Device Driver ---A Hello World Module

A simple Hello Wrold Module

 

Source Code:

#include <linux/init.h>
#include <linux/module.h>
MODULE_LICENSE("GPL"); /*这行用于告诉内核该模块拥有free license,在2.6中这是必须的*/
/*执行真正的初始化工作*/
static int hello_init(void)
{
     printk(KERN_ALERT "Hello, world\n");
      return 0;
}
/*执行真正的析构工作*/
static void hello_exit(void) {
   printk(KERN_ALERT "Goodbye, cruel world\n");
}
/*该函数注册模块的构造函数*/
module_init(hello_init);
/*该函数注册模块的析构函数*/
module_exit(hello_exit);

Makefile:

obj-m += hello.o
KERNEL_VERSION = /lib/modules/$(shell uname -r)/build/
#PWD := $(shell pwd)
all:
        make -C $(KERNEL_VERSION) M=$(PWD) modules
clean:
        make -C $(KERNEL_VERSION) M=$(PWD) clean

Directory

/"your_dir"/helloworld/hello.c

/"your_dir"/helloworld/Makefile

 

Command

install module:

insmod hello.ko

cat /var/log/message

 

rmmod hello.ko

cat /var/log/message

 

finished.