nixpkgs/pkgs/tools/X11/xkbvalidate/default.nix
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 #23709.

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 (#25526).

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 (NixOS/nix#1426).

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: #27597
2017-07-28 12:39:55 +02:00

15 lines
424 B
Nix

{ lib, runCommandCC, libxkbcommon }:
runCommandCC "xkbvalidate" {
buildInputs = [ libxkbcommon ];
meta = {
description = "NixOS tool to validate X keyboard configuration";
license = lib.licenses.mit;
platforms = lib.platforms.linux;
maintainers = [ lib.maintainers.aszlig ];
};
} ''
mkdir -p "$out/bin"
gcc -std=gnu11 -Wall -pedantic -lxkbcommon ${./xkbvalidate.c} \
-o "$out/bin/validate"
''