Proc内核通信方式示例

1、内核模块实现创建Proc下的目录和文件以及读写操作

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/utsname.h>
#include <linux/fs.h>
#include <asm/uaccess.h>
#include <linux/seq_file.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("SIR ZHANG");
MODULE_DESCRIPTION("test hello word");

static struct proc_dir_entry* des;
static struct proc_dir_entry* parent;



static ssize_t procfile_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
    int len;
    static char my_buffer[20];
    if(*offset > 0)
        return 0;
    len = sprintf(my_buffer,"hello word\n");
    copy_to_user(buf,my_buffer,len);
    
    printk("read helloword\n");
    return len;
}

int procfile_open(struct inode *inode,struct file *file)
{
    printk("open proc helloword\n");
    return 0;
}

static ssize_t procfile_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
{
    printk("write helloword\n");
    return 0;
}

static struct file_operations f_ops = {
    .owner = THIS_MODULE,
    .read = procfile_read,
    .open = procfile_open,
    .write = procfile_write,
};

int init_module()
{
    parent = proc_mkdir("hello",NULL);
    //des = create_proc_entry("word",0777,parent);
    des = proc_create("word",0777,parent,&f_ops);
    //des->proc_fops = &f_ops;
    //des->read = 
    printk("module load success\n");
    
    return 0;
}

void cleanup_module()
{
    //remove_proc_entry("word",parent);
    proc_remove(des);
    proc_remove(parent);
    printk("unload success\n");
}

//module_init(init_module);
//module_exit(cleanup_module);

2、内核模块的编译Makefile

ifneq ($(KERNELRELEASE),)

obj-m :=     helloword.o
module-objs := helloword.o

else

KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)

default:
    $(MAKE) -C $(KERNELDIR) M=$(PWD) modules
clean:
    rm -f *.o *~core .depend *.mod.c Module.marker *.order *.ko

endif