services: kmscon: Add keyboard-layout fields.

* gnu/services/base.scm (<kmscon-configuration>): Add keyboard-layout fields.
* doc/guix.texi (Base Services): Document them.

Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>

doc/guix.texi

@@ -93,6 +93,7 @@ Copyright @copyright{} 2021 B. Wilson@*
 Copyright @copyright{} 2021 Xinglu Chen@*
 Copyright @copyright{} 2021 Raghav Gururajan@*
 Copyright @copyright{} 2021 Domagoj Stolfa@*
+Copyright @copyright{} 2021 Hui Lu@*
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -15282,6 +15283,14 @@ Font engine used in Kmscon.
 @item @code{font-size} (default: @code{12})
 Font size used in Kmscon.
 
+@item @code{keyboard-layout} (default: @code{#f})
+If this is @code{#f}, Kmscon uses the default keyboard layout---usually US
+English (``qwerty'') for a 105-key PC keyboard.
+
+Otherwise this must be a @code{keyboard-layout} object specifying the
+keyboard layout.  @xref{Keyboard Layout}, for more information on how to
+specify the keyboard layout.
+
 @item @code{kmscon} (default: @var{kmscon})
 The Kmscon package to use.
 

gnu/services/base.scm

@@ -14,6 +14,7 @@
 ;;; Copyright © 2020 Florian Pelz <pelzflorian@pelzflorian.de>
 ;;; Copyright © 2020 Brice Waegeneire <brice@waegenei.re>
 ;;; Copyright © 2021 qblade <qblade@protonmail.com>
+;;; Copyright © 2021 Hui Lu <luhuins@163.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -41,6 +42,7 @@ (define-module (gnu services base)
   #:use-module (gnu system shadow)                ; 'user-account', etc.
   #:use-module (gnu system uuid)
   #:use-module (gnu system file-systems)          ; 'file-system', etc.
+  #:use-module (gnu system keyboard)
   #:use-module (gnu system mapped-devices)
   #:use-module ((gnu system linux-initrd)
                 #:select (file-system-packages))
@@ -2267,7 +2269,9 @@ (define-record-type* <kmscon-configuration>
   (font-engine             kmscon-configuration-font-engine
                            (default "pango"))
   (font-size               kmscon-configuration-font-size
-                           (default 12)))
+                           (default 12))
+  (keyboard-layout         kmscon-configuration-keyboard-layout
+                           (default #f))) ; #f | <keyboard-layout>
 
 (define kmscon-service-type
   (shepherd-service-type
@@ -2280,7 +2284,8 @@ (define kmscon-service-type
            (auto-login (kmscon-configuration-auto-login config))
            (hardware-acceleration? (kmscon-configuration-hardware-acceleration? config))
            (font-engine (kmscon-configuration-font-engine config))
-           (font-size (kmscon-configuration-font-size config)))
+           (font-size (kmscon-configuration-font-size config))
+           (keyboard-layout (kmscon-configuration-keyboard-layout config)))
 
        (define kmscon-command
          #~(list
@@ -2289,6 +2294,18 @@ (define kmscon-command
             "--no-switchvt" ;Prevent a switch to the virtual terminal.
             "--font-engine" #$font-engine
             "--font-size" #$(number->string font-size)
+            #$@(if keyboard-layout
+                   (let* ((layout (keyboard-layout-name keyboard-layout))
+                          (variant (keyboard-layout-variant keyboard-layout))
+                          (model (keyboard-layout-model keyboard-layout))
+                          (options (keyboard-layout-options keyboard-layout)))
+                     `("--xkb-layout" ,layout
+                       ,@(if variant `("--xkb-variant" ,variant) '())
+                       ,@(if model `("--xkb-model" ,model) '())
+                       ,@(if (null? options)
+                             '()
+                             `("--xkb-options" ,(string-join options ",")))))
+                   '())
             #$@(if hardware-acceleration? '("--hwaccel") '())
             "--login" "--"
             #$login-program #$@login-arguments