gnu: Add colord service.

* gnu-system.am (GNU_SYSTEM_MODULES): Add gnu/services/colord.scm.
* gnu/services/colord.scm: New file.
* doc/guix.texi (Various Services): Document it.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

doc/guix.texi

@@ -4788,6 +4788,16 @@ Finally, @var{extra-options} is a list of additional command-line options
 passed to @command{lircd}.
 @end deffn
 
+@code{(gnu services colord)} provides a color management service:
+
+@deffn {Monadic Procedure} colord-service [#:colord @var{colord}]
+Return a service that runs @command{colord}, a system service with a D-Bus
+interface to manage the color profiles of input and output devices such as
+screens and scanners.  It is notably used by the GNOME Color Manager graphical
+tool.  See @uref{http://www.freedesktop.org/software/colord/, the colord web
+site} for more information.
+@end deffn
+
 @node Setuid Programs
 @subsection Setuid Programs
 

gnu-system.am

@@ -324,6 +324,7 @@ GNU_SYSTEM_MODULES =				\
   gnu/services.scm				\
   gnu/services/avahi.scm			\
   gnu/services/base.scm				\
+  gnu/services/colord.scm			\
   gnu/services/dbus.scm				\
   gnu/services/dmd.scm				\
   gnu/services/lirc.scm				\

gnu/services/colord.scm

@@ -0,0 +1,72 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014, 2015 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2015 Andy Wingo <wingo@igalia.com>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu services colord)
+  #:use-module (gnu services)
+  #:use-module (gnu system shadow)
+  #:use-module (gnu packages gnome)
+  #:use-module (ice-9 match)
+  #:use-module (guix monads)
+  #:use-module (guix store)
+  #:use-module (guix gexp)
+  #:export (colord-service))
+
+;;; Commentary:
+;;;
+;;; This module provides service definitions for the colord color management
+;;; service.
+;;;
+;;; Code:
+
+(define* (colord-service #:key (colord colord))
+  "Return a service that runs @command{colord}, a system service with a D-Bus
+interface to manage the color profiles of input and output devices such as
+screens and scanners.  It is notably used by the GNOME Color Manager graphical
+tool.  See @uref{http://www.freedesktop.org/software/colord/, the colord web
+site} for more information."
+  (with-monad %store-monad
+    (return
+     (service
+      (documentation "Run the colord color management service.")
+      (provision '(colord-daemon))
+      (requirement '(dbus-system udev))
+
+      (start #~(make-forkexec-constructor
+                (list (string-append #$colord "/libexec/colord"))))
+      (stop #~(make-kill-destructor))
+      (activate #~(begin
+                    (use-modules (guix build utils))
+                    (mkdir-p "/var/lib/colord")
+                    (let ((user (getpwnam "colord")))
+                      (chown "/var/lib/colord"
+                             (passwd:uid user) (passwd:gid user)))))
+
+      (user-groups (list (user-group
+                          (name "colord")
+                          (system? #t))))
+      (user-accounts (list (user-account
+                            (name "colord")
+                            (group "colord")
+                            (system? #t)
+                            (comment "colord daemon user")
+                            (home-directory "/var/empty")
+                            (shell
+                             "/run/current-system/profile/sbin/nologin"))))))))
+
+;;; colord.scm ends here