在内核中创建一个简单的只写proc条目

本文介绍了在内核中创建一个简单的只写proc条目的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 #include <linux/module.h> #include <linux/kernel.h> #include <linux/proc_fs.h> #include<linux/sched.h> #include <asm/uaccess.h> #include <linux/slab.h> char *msg; ssize_t write_proc(struct file *filp,const char *buf,size_t count,loff_t *offp) { copy_from_user(msg,buf,count); printk(KERN_INFO "%s",msg); return count; } struct file_operations proc_fops = { write: write_proc }; int proc_init (void) { proc_create("write",0,NULL,&proc_fops); return 0; } void proc_cleanup(void) { remove_proc_entry("write",NULL); } MODULE_LICENSE("GPL"); module_init(proc_init); module_exit(proc_cleanup);

当我使用命令 echo'hello'>/proc/write 在终端上什么也没有显示.您能帮我发现代码中的错误吗?我在上面写的字符串应该已经显示在终端上.

When I used the command echo 'hello' > /proc/write Nothing show up on terminal . Can you help me to find mistakes in the code ? The string that I writed on it should have show up on terminal.

示例:

$ echo'hello'>/proc/write

$ echo 'hello' > /proc/write

你好

推荐答案

以下是对代码的一些简单修改:

Here are some simple modifications on your code:

#define MSG_SIZE (512) static char *msg; #define ourmin(a,b) (((a)<(b)) ? (a) : (b)) ssize_t write_proc(struct file *filp,const char *buf,size_t count,loff_t *offp) { unsigned long actual_len = ourmin(count, MSG_SIZE-1); memset(msg, 0, MSG_SIZE); copy_from_user(msg, buf, actual_len); printk(KERN_DEBUG "Got: %s",msg); return count; } int proc_init (void) { // Allocate space for msg if ((msg = kmalloc(MSG_SIZE, GFP_KERNEL)) == NULL) return -ENOMEM; // Should check the output of this too proc_create("write",0,NULL,&proc_fops); return 0; } void proc_cleanup(void) { remove_proc_entry("write",NULL); kfree(msg); }

我可以在内核日志(例如 dmesg )中检索输出.

I could retrieve the output in the kernel log (dmesg for instance).