nixos/xserver: add option to install custom xkb layouts (#47764)

nixos/xserver: add option to install custom xkb layouts
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Silvan Mosberger 2019-07-26 20:43:37 +02:00 committed by GitHub
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4 changed files with 379 additions and 2 deletions

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@ -125,10 +125,12 @@
You will need to reboot after enabling this driver to prevent a clash with
other kernel modules.
</para>
<note>
<para>
Note: for recent AMD GPUs you most likely want to keep either the defaults
For recent AMD GPUs you most likely want to keep either the defaults
or <literal>"amdgpu"</literal> (both free).
</para>
</note>
</simplesect>
<simplesect xml:id="sec-x11-touchpads">
<title>Touchpads</title>
@ -157,4 +159,134 @@
versions.
</para>
</simplesect>
<simplesect xml:id="custom-xkb-layouts">
<title>Custom XKB layouts</title>
<para>
It is possible to install custom
<link xlink:href="https://en.wikipedia.org/wiki/X_keyboard_extension">
XKB
</link>
keyboard layouts using the option
<option>
<link linkend="opt-services.xserver.extraLayouts">
services.xserver.extraLayouts
</link>
</option>.
As a first example, we are going to create a layout based on the basic US
layout, with an additional layer to type some greek symbols by pressing the
right-alt key.
</para>
<para>
To do this we are going to create a <literal>us-greek</literal> file
with a <literal>xkb_symbols</literal> section.
</para>
<programlisting>
xkb_symbols &quot;us-greek&quot;
{
include &quot;us(basic)&quot; // includes the base US keys
include &quot;level3(ralt_switch)&quot; // configures right alt as a third level switch
key &lt;LatA&gt; { [ a, A, Greek_alpha ] };
key &lt;LatB&gt; { [ b, B, Greek_beta ] };
key &lt;LatG&gt; { [ g, G, Greek_gamma ] };
key &lt;LatD&gt; { [ d, D, Greek_delta ] };
key &lt;LatZ&gt; { [ z, Z, Greek_zeta ] };
};
</programlisting>
<para>
To install the layout, the filepath, a description and the list of
languages must be given:
</para>
<programlisting>
<xref linkend="opt-services.xserver.extraLayouts"/>.us-greek = {
description = "US layout with alt-gr greek";
languages = [ "eng" ];
symbolsFile = /path/to/us-greek;
}
</programlisting>
<note>
<para>
The name should match the one given to the
<literal>xkb_symbols</literal> block.
</para>
</note>
<para>
The layout should now be installed and ready to use: try it by
running <literal>setxkbmap us-greek</literal> and type
<literal>&lt;alt&gt;+a</literal>. To change the default the usual
<option>
<link linkend="opt-services.xserver.layout">
services.xserver.layout
</link>
</option>
option can still be used.
</para>
<para>
A layout can have several other components besides
<literal>xkb_symbols</literal>, for example we will define new
keycodes for some multimedia key and bind these to some symbol.
</para>
<para>
Use the <emphasis>xev</emphasis> utility from
<literal>pkgs.xorg.xev</literal> to find the codes of the keys of
interest, then create a <literal>media-key</literal> file to hold
the keycodes definitions
</para>
<programlisting>
xkb_keycodes &quot;media&quot;
{
&lt;volUp&gt; = 123;
&lt;volDown&gt; = 456;
}
</programlisting>
<para>
Now use the newly define keycodes in <literal>media-sym</literal>:
</para>
<programlisting>
xkb_symbols &quot;media&quot;
{
key.type = &quot;ONE_LEVEL&quot;;
key &lt;volUp&gt; { [ XF86AudioLowerVolume ] };
key &lt;volDown&gt; { [ XF86AudioRaiseVolume ] };
}
</programlisting>
<para>
As before, to install the layout do
</para>
<programlisting>
<xref linkend="opt-services.xserver.extraLayouts"/>.media = {
description = "Multimedia keys remapping";
languages = [ "eng" ];
symbolsFile = /path/to/media-key;
keycodesFile = /path/to/media-sym;
};
</programlisting>
<note>
<para>
The function <literal>pkgs.writeText &lt;filename&gt; &lt;content&gt;
</literal> can be useful if you prefer to keep the layout definitions
inside the NixOS configuration.
</para>
</note>
<para>
Unfortunately, the Xorg server does not (currently) support setting a
keymap directly but relies instead on XKB rules to select the matching
components (keycodes, types, ...) of a layout. This means that components
other than symbols won't be loaded by default. As a workaround, you
can set the keymap using <literal>setxkbmap</literal> at the start of the
session with:
</para>
<programlisting>
<xref linkend="opt-services.xserver.displayManager.sessionCommands"/> = "setxkbmap -keycodes media";
</programlisting>
<para>
To learn how to write layouts take a look at the XKB
<link xlink:href="https://www.x.org/releases/current/doc/xorg-docs/input/XKB-Enhancing.html#Defining_New_Layouts">
documentation
</link>. More example layouts can also be found
<link xlink:href="https://wiki.archlinux.org/index.php/X_KeyBoard_extension#Basic_examples">
here
</link>.
</para>
</simplesect>
</chapter>

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@ -815,6 +815,7 @@
./services/web-servers/uwsgi.nix
./services/web-servers/varnish/default.nix
./services/web-servers/zope2.nix
./services/x11/extra-layouts.nix
./services/x11/colord.nix
./services/x11/compton.nix
./services/x11/unclutter.nix

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@ -0,0 +1,165 @@
{ config, lib, pkgs, ... }:
with lib;
let
layouts = config.services.xserver.extraLayouts;
layoutOpts = {
options = {
description = mkOption {
type = types.str;
description = "A short description of the layout.";
};
languages = mkOption {
type = types.listOf types.str;
description =
''
A list of languages provided by the layout.
(Use ISO 639-2 codes, for example: "eng" for english)
'';
};
compatFile = mkOption {
type = types.nullOr types.path;
default = null;
description = ''
The path to the xkb compat file.
This file sets the compatibility state, used to preserve
compatibility with xkb-unaware programs.
It must contain a <literal>xkb_compat "name" { ... }</literal> block.
'';
};
geometryFile = mkOption {
type = types.nullOr types.path;
default = null;
description = ''
The path to the xkb geometry file.
This (completely optional) file describes the physical layout of
keyboard, which maybe be used by programs to depict it.
It must contain a <literal>xkb_geometry "name" { ... }</literal> block.
'';
};
keycodesFile = mkOption {
type = types.nullOr types.path;
default = null;
description = ''
The path to the xkb keycodes file.
This file specifies the range and the interpretation of the raw
keycodes sent by the keyboard.
It must contain a <literal>xkb_keycodes "name" { ... }</literal> block.
'';
};
symbolsFile = mkOption {
type = types.nullOr types.path;
default = null;
description = ''
The path to the xkb symbols file.
This is the most important file: it defines which symbol or action
maps to each key and must contain a
<literal>xkb_symbols "name" { ... }</literal> block.
'';
};
typesFile = mkOption {
type = types.nullOr types.path;
default = null;
description = ''
The path to the xkb types file.
This file specifies the key types that can be associated with
the various keyboard keys.
It must contain a <literal>xkb_types "name" { ... }</literal> block.
'';
};
};
};
in
{
###### interface
options.services.xserver = {
extraLayouts = mkOption {
type = types.attrsOf (types.submodule layoutOpts);
default = {};
example = literalExample
''
{
mine = {
description = "My custom xkb layout.";
languages = [ "eng" ];
symbolsFile = /path/to/my/layout;
};
}
'';
description = ''
Extra custom layouts that will be included in the xkb configuration.
Information on how to create a new layout can be found here:
<link xlink:href="https://www.x.org/releases/current/doc/xorg-docs/input/XKB-Enhancing.html#Defining_New_Layouts"></link>.
For more examples see
<link xlink:href="https://wiki.archlinux.org/index.php/X_KeyBoard_extension#Basic_examples"></link>
'';
};
};
###### implementation
config = mkIf (layouts != { }) {
# We don't override xkeyboard_config directly to
# reduce the amount of packages to be recompiled.
# Only the following packages are necessary to set
# a custom layout anyway:
nixpkgs.overlays = lib.singleton (self: super: {
xkb_patched = self.xorg.xkeyboardconfig_custom {
layouts = config.services.xserver.extraLayouts;
};
xorg = super.xorg // {
xorgserver = super.xorg.xorgserver.overrideAttrs (old: {
configureFlags = old.configureFlags ++ [
"--with-xkb-bin-directory=${self.xorg.xkbcomp}/bin"
"--with-xkb-path=${self.xkb_patched}/share/X11/xkb"
];
});
setxkbmap = super.xorg.setxkbmap.overrideAttrs (old: {
postInstall =
''
mkdir -p $out/share
ln -sfn ${self.xkb_patched}/etc/X11 $out/share/X11
'';
});
xkbcomp = super.xorg.xkbcomp.overrideAttrs (old: {
configureFlags = "--with-xkb-config-root=${self.xkb_patched}/share/X11/xkb";
});
};
ckbcomp = super.ckbcomp.override {
xkeyboard_config = self.xkb_patched;
};
xkbvalidate = super.xkbvalidate.override {
libxkbcommon = self.libxkbcommon.override {
xkeyboard_config = self.xkb_patched;
};
};
});
services.xserver.xkbDir = "${pkgs.xkb_patched}/etc/X11/xkb";
};
}

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@ -1,7 +1,7 @@
{ abiCompat ? null,
stdenv, makeWrapper, fetchurl, fetchpatch, buildPackages,
automake, autoconf, gettext, libiconv, libtool, intltool,
freetype, tradcpp, fontconfig, meson, ninja,
freetype, tradcpp, fontconfig, meson, ninja, ed,
libGL, spice-protocol, zlib, libGLU, dbus, libunwind, libdrm,
mesa, udev, bootstrap_cmds, bison, flex, clangStdenv, autoreconfHook,
mcpp, epoxy, openssl, pkgconfig, llvm_6,
@ -423,6 +423,85 @@ self: super:
'';
});
# xkeyboardconfig variant extensible with custom layouts.
# See nixos/modules/services/x11/extra-layouts.nix
xkeyboardconfig_custom = { layouts ? { } }:
let
patchIn = name: layout:
with layout;
with lib;
''
# install layout files
${optionalString (compatFile != null) "cp '${compatFile}' 'compat/${name}'"}
${optionalString (geometryFile != null) "cp '${geometryFile}' 'geometry/${name}'"}
${optionalString (keycodesFile != null) "cp '${keycodesFile}' 'keycodes/${name}'"}
${optionalString (symbolsFile != null) "cp '${symbolsFile}' 'symbols/${name}'"}
${optionalString (typesFile != null) "cp '${typesFile}' 'types/${name}'"}
# patch makefiles
for type in compat geometry keycodes symbols types; do
if ! test -f "$type/${name}"; then
continue
fi
test "$type" = geometry && type_name=geom || type_name=$type
${ed}/bin/ed -v $type/Makefile.am <<EOF
/''${type_name}_DATA =
a
${name} \\
.
w
EOF
${ed}/bin/ed -v $type/Makefile.in <<EOF
/''${type_name}_DATA =
a
${name} \\
.
w
EOF
done
# add model description
${ed}/bin/ed -v rules/base.xml <<EOF
/<\/modelList>
-
a
<model>
<configItem>
<name>${name}</name>
<_description>${layout.description}</_description>
<vendor>${layout.description}</vendor>
</configItem>
</model>
.
w
EOF
# add layout description
${ed}/bin/ed -v rules/base.xml <<EOF
/<\/layoutList>
-
a
<layout>
<configItem>
<name>${name}</name>
<_shortDescription>${name}</_shortDescription>
<_description>${layout.description}</_description>
<languageList>
${concatMapStrings (lang: "<iso639Id>${lang}</iso639Id>\n") layout.languages}
</languageList>
</configItem>
<variantList/>
</layout>
.
w
EOF
'';
in
self.xkeyboardconfig.overrideAttrs (old: {
buildInputs = old.buildInputs ++ [ automake ];
postPatch = with lib; concatStrings (mapAttrsToList patchIn layouts);
});
xload = super.xload.overrideAttrs (attrs: {
nativeBuildInputs = attrs.nativeBuildInputs ++ [ gettext ];
});