Linux 5.5 Finally Doing Away With The SYSCTL System Call

[F.Ultra]

I'll just ask the obvious question: why prefer /proc/sys/ over sysctl()?

Is the issue just that one is implemented in terms of the other, and they want to remove the glue code? I guess the function call requires one or more enums that essentially encode the nodes in the /proc/sys/ path string, and folks don't want to maintain both those enums and the actual path strings?

https://linux.die.net/man/2/sysctl

Looking at the original announcement from 2010 Eric Biederman states these reasons:

*Binary sysctls are a long standing source of subtle kernel bugs and security issues.

*The man page for sysctl(2) documents it as unusable for user space programs.

*sysctl(2) is not generally ABI compatible to a 32bit user space application on a 64bit and a 32bit kernel.

[drjohnnyfever]

I find it interesting that Linux and FreeBSD went in opposite directions on this. FreeBSD deprecated the procfs interface (which as far as I know is implemented with sysctl(2) on FreeBSD) and Linux deprecated sysctl in favor of procfs.

[xen0n]

Is "sysctl" conneted via REISUB commands - it's still very useful for me with buggy graphic drivers/compositors/etc ?
Also does "sysctl" enable some reading/writing from motherboard ?

What you're referring to is "magic SysRq", which is a totally different beast and is not affected at all.

[gsedej]

Is "sysctl" conneted via REISUB commands - it's still very useful for me with buggy graphic drivers/compositors/etc ?
Also does "sysctl" enable some reading/writing from motherboard ?

[coder]

I'll just ask the obvious question: why prefer /proc/sys/ over sysctl()?

Is the issue just that one is implemented in terms of the other, and they want to remove the glue code? I guess the function call requires one or more enums that essentially encode the nodes in the /proc/sys/ path string, and folks don't want to maintain both those enums and the actual path strings?

https://linux.die.net/man/2/sysctl

[phoronix]

Phoronix: Linux 5.5 Finally Doing Away With The SYSCTL System Call

The Linux 5.5 kernel is set to finally eliminate the code backing the sysctl system call, which has been deprecated for about a decade and should have no impact on modern systems of any architecture...

http://www.phoronix.com/scan.php?page=news_item&px=Linux-5.5-Kills-SYSCTL-SYSCALL