CODEWITHSUNDEEP
clinuxlinux-kernelkernel
Sajad Bahmani
Sajad Bahmani

Reputation: 17459

Kernel module for /proc

How to write a kernel module that creates a directory in /proc named mymod and a file in it name is mymodfile. This file should accept a number ranged from 1 to 3 when written into it and return the following messages when read based on the number already written into it:

• 1: Current system time (in microseconds precision)
• 2: System uptime
• 3: Number of processes currently in the system

“The Output”

root@Paradise# echo 1 > /proc/mymod/mymodfile
root@Paradise# cat /proc/mymod/mymodfile
08:30:24 342us
root@Paradise# echo 2 > /proc/mymod/mymodfile
root@Paradise# cat /proc/mymod/mymodfile
up 1 day, 8 min 
root@Paradise# echo 3 > /proc/mymod/mymodfile
root@Paradise# cat /proc/mymod/mymodfile
process count: 48

please give me some hint how to write a kernel modules and how to compile and install it .

Upvotes: 2

Views: 4503

Answers (3)

Eric Seppanen
Eric Seppanen

Reputation: 6081

This might be easier to do using sysfs. Sysfs was designed with these sorts of operations in mind, and has simple functions for creating directories and virtual files and callbacks for read and write operations to those files.

Upvotes: -1

Aif
Aif

Reputation: 11220

There is an article about this in a french magazine called "Gnu/Linux magazine" this month.

I don't have my bookmarks here, but theses links look ok:

http://www.linuxhq.com/lkprogram.html

http://tldp.org/HOWTO/Module-HOWTO/x839.html

http://tldp.org/LDP/lkmpg/2.6/html/lkmpg.html

Upvotes: 1

Nick Bastin
Nick Bastin

Reputation: 31299

What you're looking for is the Linux Kernel Module Programming Guide, specifically the section on the /proc filesystem, which has well documented examples of how to add new entries.

Upvotes: 7

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