前提
- 実行後にログを出力するだけのデバイスドライバ
- register_chrdevを使用（カーネル2.6系以降は推奨されないらしい）
- Ubuntu 16.04、Windows/VMWare
- Linux ubuntu 4.4.0-91-generic #114-Ubuntu SMP Tue Aug 8 11:56:56 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
- エラーハンドリングは無し
メモ
コード
simple_kernelmodule.c
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#define NODE_NAME "kuredev"
#define SUCCESS 0
MODULE_LICENSE("Dual BSD/GPL");
static int major_num = 0;
static int kure_open(struct inode *inode, struct file *file){
printk("kure_open\n");
return SUCCESS;
}
static int kure_release(struct inode *inode, struct file *file){
printk("kure_release\n");
return SUCCESS;
}
static ssize_t kure_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos){
printk("kure_read\n");
return count;
}
static ssize_t kure_write(struct file *file, char __user *buf, size_t count,loff_t *f_pos){
printk("kure_write\n");
return count;
}
struct file_operations kure_fops = {
.owner = THIS_MODULE,
.read = kure_read,
.write = kure_write,
.open = kure_open,
.release = kure_release
};
static int kure_init(void){
major_num = register_chrdev(major_num, NODE_NAME, &kure_fops);
printk("kure_init\n");
return SUCCESS;
}
static void kure_exit(void){
unregister_chrdev(major_num, NODE_NAME);
printk("kure_exit\n");
}
module_init(kure_init);
module_exit(kure_exit);
Makefile
KERNEL_DIR = /lib/modules/$(shell uname -r)/build
BUILD_DIR := $(shell pwd)
VERBOSE := 0
obj-m := simple_kernelmodule.o
all:
make -C $(KERNEL_DIR) SUBDIRS=$(BUILD_DIR) KBUILD_VERBOSE=$(VERBOSE) modules
clean:
rm -rf *.o *.ko *.mod.c *.symvers *.order .tmp_versions .helloworld.*
実行結果
# make
# insmod simple_kernelmodule.ko
# cat /proc/devices | grep kure
246 kuredev
# mknod -m 666 /dev/kuredev c 246 0
# echo 0 > /dev/kuredev
# rmmod simple_kernelmodule
実行結果（syslog）
Aug 13 05:14:01 ubuntu kernel: [ 9907.393185] kure_init ★insmod
Aug 13 05:15:11 ubuntu kernel: [ 9978.162543] kure_open ★echo
Aug 13 05:15:11 ubuntu kernel: [ 9978.162552] kure_write
Aug 13 05:15:11 ubuntu kernel: [ 9978.162554] kure_release
Aug 13 05:15:35 ubuntu kernel: [10002.117217] kure_exit ★rmmod
参考
