Allow enable/disable some keyboard combinations.

[ray]

Summary

Add sysctls to allow enable/disable some keyboard combinations.

[dumbbell]

What are these key combinations? Does it have something to do with Ctrl+Alt+Esc in syscons to break into ddb?

[emaste]

sys/dev/vt/vt_core.c

129

underscore not needed in description

131

"Enable debugger keyboard combination"?

500–528

strange whitespace?

[emaste]

What are these key combinations?

Yes, the key map converts a few combinations into halt / reboot / debugger etc. "keys" -- see halt/pdwn/debug/susp/saver/panic in kbdmap(5)

[dumbbell]

See inline comments.

Also, where are those key combinations documented? Are they configurable? If not, it may be helpful to have them in the sysctl description.

sys/dev/vt/vt_core.c

531

I know that syscons used the same call, but you may use the RB_AUTOBOOT flag instead of 0.

[emaste]

They are configurable by a keymap, meaning we'd need something like

"Enable key combination to enter debugger (typically Ctrl-Alt-Esc)"

(or "by default" etc.)

[dumbbell]

Yeah, I think that this description helps. For instance, I don't know the combinations for reboot/halt/poweroff :) I thought Ctrl-Alt-Del was handled by init(8) but I may be wrong and simply confuse with Linux.

Regarding the text, I like your second suggestion, "... (by default, Ctrl-Alt-Esc)".

[ray]

o Extend descriptions for reboot and debug.
o Use RB_AUTOBOOT.

[ray]

Guys,
how is it looks now? :)

sys/dev/vt/vt_core.c

129

Same as debug case, it is combination name. so not "power off", but something like "Power-Off"

131

I like "Enable \"Enter DDB\" keyboard combination" more. If it applicable :)

500–528

Hmmm, where is it?

[dumbbell]

sys/dev/vt/vt_core.c

129

You forgot to change power_off to power off (no underscore).

What are the combinations for the two actions above?

131

So Ctrl-Alt-Delete is really the key combination for that action?

[ray]

Lets look it from other point of view:
o Implement all special combinations that syscons(4) have.
o Point to kbdmap(5) for reference.

[ray]

btw, anybody know where to get scancodes without making experiments? :)

[dumbbell]

sys/dev/vt/vt_core.c

138

Thanks, the description is way more helpful like this.

Just a minor comment: I would move the "(typically ...)" brackets after the "See kbdmap(5)" but before the final ".":

​VT_SYSCTL_INT(kbd_reboot, 1, "Enable reboot keyboard combination. "
 "See kbdmap(5) to configure (typically Ctrl-Alt-Delete).");

And don't mix single-space and double-space after a ".".

[dumbbell]

Oh and no, I don't know an official list of scancodes :)

[ray]

Committed as r271381.
Thank you guys!

sys/dev/vt/vt_core.c

138

ok, get it. And fixed.
Will commit it (changes not so critical to wait all reviewers :) )