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Author SHA1 Message Date
aszlig
6e5d2f8963
nixos/xserver: Properly validate XKB options
Checking the keyboard layout has been a long set of hurdles so far, with
several attempts. Originally, the checking was introduced by @lheckemann
in .

The initial implementation just was trying to check whether the symbols/
directory contained the layout name.

Unfortunately, that wasn't enough and keyboard variants weren't
recognized, so if you set layout to eg. "dvorak" it will fail with an
error ().

So my improvement on that was to use sed to filter rules/base.lst and
match the layout against that. I fucked up twice with this, first
because layout can be a comma-separated list which I didn't account for
and second because I ran into a Nix issue ().

After fixing this, it still wasn't enough (and this is btw. what
localectl also does), because we were *only* matching rules but not
symbols, so using "eu" as a layout won't work either.

I decided now it's the time to actually use libxkbcommon to try
compiling the keyboard options and see whether it succeeds. This comes
in the form of a helper tool called xkbvalidate.

IMHO this approach is a lot less error-prone and we can be sure that we
don't forget about anything because that's what the X server itself uses
to compile the keymap.

Another advantage of this is that we now validate the full set of XKB
options rather than just the layout.

Tested this against a variety of wrong and correct keyboard
configurations and against the "keymap" NixOS VM tests.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Cc: @lheckemann, @peti, @7c6f434c, @tohl, @vcunat, @lluchs
Fixes: 
2017-07-28 12:39:55 +02:00