Operating System Concept Ninth Edition Programming Project: Linux Kernel Module

The source code is at the end

Experiment title:

Source code package download
Link: Click here to download Password: i2ev

(The first part of the experiment is the operation on the virtual machine, and the second part is the operation on the real machine)
1. Create a kernel module

Compile module

2, loading and unloading kernel module
is loaded

Delete kernel module

the second part

Functions of several main kernel functions
1, brithday_init(): register the entry point of the module to the kernel
2, list_for_each_entry(ptr, &birthday_list, list): a for loop, using the passed in pos as the loop variable, starting from the header &birthday _list , Move ptr backward one by one, and traverse the list sub-items of each ptr until it returns to &birthday_list
3, birthday_exit(): register the exit point of the module with the kernel
1, compile the module, and generate the brithday.ko file
Command line: make

2. Call the kernel function and view the log.
Command line 1: sudo insmod brithday.ko
command line 2: dmesg

Exit the kernel function call and view the log, and finally clear the kernel log.
Command line 1: sudo rmmod brithday Command line 2: dmesg Command line 3: sudo dmesg -c

Code one
Code name:birthday.c

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/init.h>
//声明一个list_head对象
 static LIST_HEAD(brithday_list);
//定义插入链表的结构
struct brithday {
    
    
    int day;
   int month;
   int year;
   struct list_head list;
};
//brithday()将实例添加到链表中，(通过list_add_tail()函数)，通过引用函数避免代码重复
void brithday(int day, int month, int year, struct brithday *person)
{
    
    
   person->day=day;
   person->month=month;
   person->year=year;
   INIT_LIST_HEAD(&person->list);
   list_add_tail(&person->list, &brithday_list);
}
//内核模块入口函数
int brithday_init(void){
    
    
//创建并初始化struct brithday的实例
   struct brithday *person;
   struct brithday *ptr;
 char n[5]={
    
    'a','b','c','d','e'};
   int i=0;
//设置五个人的名字，便于区分
  
   person = kmalloc(sizeof(*person)*5, GFP_KERNEL);
   brithday(1,10,2020,person);
   person=person+1;
   brithday(2,9,2021,person);
   person=person+1;
   brithday(3,8,2022,person);
   person=person+1;
   brithday(4,7,2023,person);
   person=person+1;
   brithday(5,6,2024,person);
   //遍历链表并循环输出五个人的出生日期到缓冲区
   list_for_each_entry(ptr, &brithday_list, list) {
    
    
      printk(KERN_INFO "%c 的出生日期是： %d 年 %d月 %d 日.\n",n[i],ptr->year,ptr->month,ptr->day);
      i=i+1;
   }
printk(KERN_INFO "Loading Module\n");

   return 0;
}
//内核注册模块的退出函数
void brithday_exit(void)
{
    
    
   struct brithday *ptr, *next;
   list_for_each_entry_safe(ptr, next, &brithday_list, list){
    
    
      list_del(&ptr->list);
      kfree(ptr);
   }
   printk(KERN_INFO "Removing Moudle\n");
}
module_init(brithday_init);
module_exit(brithday_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Birthday Module");
MODULE_AUTHOR("SGG");

Code Two
File name: makefile

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