kernelHow to read/write files within kernel module?

Posted by Methos on Stack Overflow See other posts from Stack Overflow or by Methos
Published on 2009-07-26T10:59:12Z Indexed on 2010/04/23 20:53 UTC
Read the original article Hit count: 451

Filed under:

linux-kernel

|

file-io

|

kernel-module

I know all the discussions about why one should not read/write files from kernel, instead how to use /proc or netlink to do that. I want to read/write anyway. I have also read http://www.linuxjournal.com/article/8110

However, problem is 2.6.30 does not export sys_read(). Rather its wrapped in SYSCALL_DEFINE3. So if I use that in my module, I get following warnings: WARNING: "sys_read" [xxx.ko] undefined! WARNING: "sys_open" [xxx.ko] undefined!

Obviously insmod cannot load the module because linking does not happen correctly.

Questions:

How to read/write within kernel after 2.6.22 (where sys_read()/sys_open() are not exported)?
In general, how to use system calls wrapped in macro SYSCALL_DEFINEn() from within the kernel?

© Stack Overflow or respective owner

Related posts about linux-kernel

Out of disk space - /boot at 100%

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
My /boot is at 100%. When I run aptitude search ~ilinux-image I'm getting loads of unused images. When I try to delete one of them (after checking which one is currently in use by doing uname -r), e.g apt-get autoremove linux-image-3.2.0-44-generic I get: Reading package lists... Done Building dependency… >>> More
Linux Kernel Threads - scheduler

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi People, Is Linux Kernel scheduler a part of init process? My understanding is that it is part of Kernel threads managed internally not visible to user by either top or ps. Please correct my understanding. Is it possible to view standard kernel threads through any kernel debugger to see how standard… >>> More
Linux kernel scheduling

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I wish to know how Old Linux scheduling algorithm SJF (shortest job first) calculates the process runtime ? >>> More
The newbie's guide to hacking the Linux kernel

as seen on Internet.com - Search for 'Internet.com'
<b>TuxRadar: </b>"We asked prolific kernel hacker (and Linux Format reader!) Greg Kroah-Hartman to tell us what it takes for newbies to patch the Linux kernel - here's what he had to say." >>> More
Google open source guru says Android code will be in Linux kernel in time

as seen on Internet.com - Search for 'Internet.com'
<b>ZDNet:</b> "Google’s Android code will assume its rightful place in the Linux kernel — in good time, the company’s top open source guru says." >>> More

Related posts about file-io

File io error Python

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a program that monitors a folder with word documents for any modifications made on the files. The error -Windows Error[2] The system cannot find the file specified- comes when I run the program, open a .doc within the folder make some changes and save it. Any suggestions on how to fix this… >>> More
Problem with File IO and splitting strings with Environment.NewLine in VB.Net

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I was experimenting with basic VB.Net file read/write and encountered this problem. I don't know whether it has something to do with the File IO or the String splitting. I am writing text to a file like so Dim sWriter As New StreamWriter("Data.txt") sWriter.WriteLine("FirstItem") sWriter.WriteLine("SecondItem") sWriter… >>> More
C# Multithreading File IO (Reading)

as seen on Stack Overflow - Search for 'Stack Overflow'
We have a situation where our application needs to process a series of files and rather than perform this function synchronously, we would like to employ multi-threading to have the workload split amongst different threads. Each item of work is: 1. Open a file for read only 2. Process the data in… >>> More
ASP.Net Application Trust Medium File IO Outside Virtual Directory

as seen on Stack Overflow - Search for 'Stack Overflow'
I am trying to determine how suicidal this is... I have a hosting environment where a custom ASP.Net CMS application needs to access the files in the root folder of a website even though it is in a virtual folder so it can be shared accross many sites. I can modify the Medium trust on the server… >>> More
On MacOSX, in a C++ program, what guarantees can I have on file IO

as seen on Stack Overflow - Search for 'Stack Overflow'
I am on MacOSX. I am writing a multi threaded program. One thread does logging. The non-logging threads may crash at any time. What conventions should I adopt in the logger / what guarantees can I have? I would prefer a solution where even if I crash during part of a write, previous writes still… >>> More