services: Add fingerprint identification service.

* gnu/services/authentication.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* doc/guix.texi (Miscellaneous Services): Document it.

doc/guix.texi

@@ -20043,6 +20043,21 @@ The port to bind the server to.
 @node Miscellaneous Services
 @subsubsection Miscellaneous Services
 
+@cindex fingerprint
+@subsubheading Fingerprint Service
+
+The @code{(gnu services fingerprint)} module provides a DBus service to
+read and identify fingerprints via a fingerprint sensor.
+
+@defvr {Scheme Variable} fprintd-service-type
+The service type for @command{fprintd}, which provides the fingerprint
+reading capability.
+
+@example
+(service fprintd-service-type)
+@end example
+@end defvr
+
 @cindex sysctl
 @subsubheading System Control Service
 

gnu/local.mk

@@ -471,6 +471,7 @@ GNU_SYSTEM_MODULES =				\
   %D%/services/desktop.scm			\
   %D%/services/dict.scm				\
   %D%/services/dns.scm				\
+  %D%/services/authentication.scm		\
   %D%/services/games.scm			\
   %D%/services/kerberos.scm			\
   %D%/services/lirc.scm				\

gnu/services/authentication.scm

@@ -0,0 +1,41 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2018 Danny Milosavljevic <dannym@scratchpost.org>
+;;;
+;;; 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 fingerprint)
+  #:use-module (gnu services)
+  #:use-module (gnu services dbus)
+  #:use-module (gnu packages freedesktop)
+  #:use-module (guix gexp)
+  #:use-module (guix records)
+  #:export (fprintd-configuration
+            fprintd-configuration?
+            fprintd-service-type))
+
+(define-record-type* <fprintd-configuration>
+  fprintd-configuration make-fprintd-configuration
+  fprintd-configuration?
+  (ntp      fprintd-configuration-fprintd
+            (default fprintd)))
+
+(define fprintd-service-type
+  (service-type (name 'fprintd)
+                (extensions
+                 (list (service-extension dbus-root-service-type
+                                          list)))
+                (description
+                 "Run fprintd, a fingerprint management daemon.")))