Replacement for kqueue within kernel mode

[Trejavathi]

In FreeBSD version 14.0, it appears that the kqueue and kevent calls are not supported within kernel modules. Could you please provide information about the alternative or replacement calls that can be used under kernel mode?

 

[SirDice]

In FreeBSD version 14.0,

They are library calls, they've never been allowed within the kernel. You cannot call userspace libraries.

 

[Trejavathi]

Kqueue and kevent are not library calls; they are system calls. However, they are typically used in user space. These functions are declared in the event.h header file under the else part of "#ifdef _KERNEL" section. I would like to know what function should be used for kqueues within a kernel module; should I be using knote and knlist?

 

[SirDice]

Kqueue and kevent are not library calls; they are system calls.

kqueue(2):

NAME
     kqueue, kevent – kernel event notification mechanism

LIBRARY
     Standard C Library (libc, -lc)

 

[Trejavathi]

You are correct. I apologize. Do we have facility similar to kqueue which can be used under kernel space?

 

[covacat]

man 9 kqueue
nm /usr/obj/usr/src/arm64.aarch64/sys/GENERIC/kern_event.o |grep " T "

 

[Kai Burghardt]

[…] kqueue(2): […]

Ahem, may I remind you of the meaning of man(1) page section numbers, intro(2) – “introduction to system calls […]”. Yes, there are libc wrappers for almost all system calls.​