如何从内核空间读取/写入linux/proc文件? [英] How to read/write from/to a linux /proc file from kernel space?

问题描述

我正在编写一个由用户程序和内核模块组成的程序.内核模块需要收集数据，然后将其发送"到用户程序.这必须通过/proc文件来完成.现在，我创建了文件，一切都很好，花了很长时间阅读互联网以寻找答案，但仍然找不到.如何从内核空间 读/写/proc文件?提供给procfile的write_proc和read_proc用于从USER空间读取和写入数据，而我需要模块能够写入/proc文件本身.

I am writing a program consisting of user program and a kernel module. The kernel module needs to gather data that it will then "send" to the user program. This has to be done via a /proc file. Now, I create the file, everything is fine, and spent ages reading the internet for answer and still cannot find one. How do you read/write a /proc file from the kernel space ? The write_proc and read_proc supplied to the procfile are used to read and write data from USER space, whereas I need the module to be able to write the /proc file itself.

推荐答案

那不是它的工作原理.当用户空间程序打开文件时，它们是根据具体情况即时生成的.它们大多数是只读的，并且是通过通用机制生成的:

That's not how it works. When a userspace program opens the files, they are generated on the fly on a case-by-case basis. Most of them are readonly and generated by a common mechanism:

• 使用create_proc_read_entry注册条目
• 提供一个回调函数(按惯例称为read_proc)，该函数在读取文件时被调用
• 此回调函数应填充提供的缓冲区，并(通常)调用proc_calc_metrics以更新提供给用户空间的文件指针等.

(从内核)您没有写"到procfs文件，而是在用户空间请求它们时动态提供结果.

You (from the kernel) do not "write" to procfs files, you supply the results dynamically when userspace requests them.

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