Using kmsgrab and triggerhappy for full-screen screenshots

[roslof]

Referring to an older thread

In the past we could use raspi2png for screengrabs, but the tech is obsolete for modern OSes. Would like to combine a modern capture tool with triggerhappy for keyboard-triggered screen captures using the method in the thread linked above.

In 2025, it seems that kmsgrab might be a good alternative with Bookworm, but it needs sudo/root access, which may prohibit it from running in a script. Wondering if there is a way to run kmsgrab in this fashion, or if a different tool would be required.

I've already configured a triggerhappy conf file and it tries to run kmsgrab with a filename param, but it definitely needs sudo, which I think is a non-starter.

Is there a clever way to make this work?

Cheers!
-Ros

EDIT: I'm realizing that this may be a Pi 5 / Bookworm issue and thus is probably not ready for this forum.

[Lolonois]

You may succeed with giving the kmsgrab system admin capabilities, it does no longer require explicit sudo then.

sudo setcap cap_sys_admin+ep /path/to/kmsgrab

https://linux.die.net/man/8/setcap
https://linux.die.net/man/3/cap_from_text
https://man7.org/linux/man-pages/man7/capabilities.7.html

I did not debug to the end, but I strongly assume at some point DRM hits this method, which bails out with -EACCES ("Operation not permitted") when privileges are not met.