;;; 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 desktop)
  #:use-module (gnu services)
  #:use-module (gnu services base)
  #:use-module (gnu services avahi)
  #:use-module (gnu services xorg)
  #:use-module (gnu services networking)
  #:use-module (gnu system shadow)
  #:use-module (gnu packages glib)
  #:use-module (gnu packages admin)
  #:use-module (gnu packages gnome)
  #:use-module (gnu packages avahi)
  #:use-module (gnu packages wicd)
  #:use-module (guix monads)
  #:use-module (guix store)
  #:use-module (guix gexp)
  #:use-module (ice-9 match)
  #:export (dbus-service
            upower-service
            colord-service
            geoclue-application
            %standard-geoclue-applications
            geoclue-service
            %desktop-services))

;;; Commentary:
;;;
;;; This module contains service definitions for a "desktop" environment.
;;;
;;; Code:


;;;
;;; Helpers.
;;;

(define (bool value)
  (if value "true\n" "false\n"))


;;;
;;; D-Bus.
;;;

(define (dbus-configuration-directory dbus services)
  "Return a configuration directory for @var{dbus} that includes the
@code{etc/dbus-1/system.d} directories of each package listed in
@var{services}."
  (define build
    #~(begin
        (use-modules (sxml simple)
                     (srfi srfi-1))

        (define (services->sxml services)
          ;; Return the SXML 'includedir' clauses for DIRS.
          `(busconfig
            ,@(append-map (lambda (dir)
                            `((includedir
                               ,(string-append dir "/etc/dbus-1/system.d"))
                              (servicedir         ;for '.service' files
                               ,(string-append dir "/share/dbus-1/services"))))
                          services)))

        (mkdir #$output)
        (copy-file (string-append #$dbus "/etc/dbus-1/system.conf")
                   (string-append #$output "/system.conf"))

        ;; The default 'system.conf' has an <includedir> clause for
        ;; 'system.d', so create it.
        (mkdir (string-append #$output "/system.d"))

        ;; 'system-local.conf' is automatically included by the default
        ;; 'system.conf', so this is where we stuff our own things.
        (call-with-output-file (string-append #$output "/system-local.conf")
          (lambda (port)
            (sxml->xml (services->sxml (list #$@services))
                       port)))))

  (gexp->derivation "dbus-configuration" build))

(define* (dbus-service services #:key (dbus dbus))
  "Return a service that runs the \"system bus\", using @var{dbus}, with
support for @var{services}.

@uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
facility.  Its system bus is used to allow system services to communicate and
be notified of system-wide events.

@var{services} must be a list of packages that provide an
@file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
and policy files.  For example, to allow avahi-daemon to use the system bus,
@var{services} must be equal to @code{(list avahi)}."
  (mlet %store-monad ((conf (dbus-configuration-directory dbus services)))
    (return
     (service
      (documentation "Run the D-Bus system daemon.")
      (provision '(dbus-system))
      (requirement '(user-processes))
      (start #~(make-forkexec-constructor
                (list (string-append #$dbus "/bin/dbus-daemon")
                      "--nofork"
                      (string-append "--config-file=" #$conf "/system.conf"))))
      (stop #~(make-kill-destructor))
      (user-groups (list (user-group
                          (name "messagebus")
                          (system? #t))))
      (user-accounts (list (user-account
                            (name "messagebus")
                            (group "messagebus")
                            (system? #t)
                            (comment "D-Bus system bus user")
                            (home-directory "/var/run/dbus")
                            (shell
                             #~(string-append #$shadow "/sbin/nologin")))))
      (activate #~(begin
                    (use-modules (guix build utils))

                    (mkdir-p "/var/run/dbus")

                    (let ((user (getpwnam "messagebus")))
                      (chown "/var/run/dbus"
                             (passwd:uid user) (passwd:gid user)))

                    (unless (file-exists? "/etc/machine-id")
                      (format #t "creating /etc/machine-id...~%")
                      (let ((prog (string-append #$dbus "/bin/dbus-uuidgen")))
                        ;; XXX: We can't use 'system' because the initrd's
                        ;; guile system(3) only works when 'sh' is in $PATH.
                        (let ((pid (primitive-fork)))
                          (if (zero? pid)
                              (call-with-output-file "/etc/machine-id"
                                (lambda (port)
                                  (close-fdes 1)
                                  (dup2 (port->fdes port) 1)
                                  (execl prog)))
                              (waitpid pid)))))))))))


;;;
;;; Upower D-Bus service.
;;;

(define* (upower-configuration-file #:key watts-up-pro? poll-batteries?
                                    ignore-lid? use-percentage-for-policy?
                                    percentage-low percentage-critical
                                    percentage-action time-low
                                    time-critical time-action
                                    critical-power-action)
  "Return an upower-daemon configuration file."
  (text-file "UPower.conf"
             (string-append
              "[UPower]\n"
              "EnableWattsUpPro=" (bool watts-up-pro?)
              "NoPollBatteries=" (bool (not poll-batteries?))
              "IgnoreLid=" (bool ignore-lid?)
              "UsePercentageForPolicy=" (bool use-percentage-for-policy?)
              "PercentageLow=" (number->string percentage-low) "\n"
              "PercentageCritical=" (number->string percentage-critical) "\n"
              "PercentageAction=" (number->string percentage-action) "\n"
              "TimeLow=" (number->string time-low) "\n"
              "TimeCritical=" (number->string time-critical) "\n"
              "TimeAction=" (number->string time-action) "\n"
              "CriticalPowerAction=" (match critical-power-action
                                       ('hybrid-sleep "HybridSleep")
                                       ('hibernate "Hibernate")
                                       ('power-off "PowerOff"))
              "\n")))

(define* (upower-service #:key (upower upower)
                         (watts-up-pro? #f)
                         (poll-batteries? #t)
                         (ignore-lid? #f)
                         (use-percentage-for-policy? #f)
                         (percentage-low 10)
                         (percentage-critical 3)
                         (percentage-action 2)
                         (time-low 1200)
                         (time-critical 300)
                         (time-action 120)
                         (critical-power-action 'hybrid-sleep))
  "Return a service that runs @uref{http://upower.freedesktop.org/,
@command{upowerd}}, a system-wide monitor for power consumption and battery
levels, with the given configuration settings.  It implements the
@code{org.freedesktop.UPower} D-Bus interface, and is notably used by GNOME."
  (mlet %store-monad ((config (upower-configuration-file
                               #:watts-up-pro? watts-up-pro?
                               #:poll-batteries? poll-batteries?
                               #:ignore-lid? ignore-lid?
                               #:use-percentage-for-policy? use-percentage-for-policy?
                               #:percentage-low percentage-low
                               #:percentage-critical percentage-critical
                               #:percentage-action percentage-action
                               #:time-low time-low
                               #:time-critical time-critical
                               #:time-action time-action
                               #:critical-power-action critical-power-action)))
    (return
     (service
      (documentation "Run the UPower power and battery monitor.")
      (provision '(upower-daemon))
      (requirement '(dbus-system udev))

      (start #~(make-forkexec-constructor
                (list (string-append #$upower "/libexec/upowerd"))
                #:environment-variables
                (list (string-append "UPOWER_CONF_FILE_NAME=" #$config))))
      (stop #~(make-kill-destructor))
      (activate #~(begin
                    (use-modules (guix build utils))
                    (mkdir-p "/var/lib/upower")
                    (let ((user (getpwnam "upower")))
                      (chown "/var/lib/upower"
                             (passwd:uid user) (passwd:gid user)))))

      (user-groups (list (user-group
                          (name "upower")
                          (system? #t))))
      (user-accounts (list (user-account
                            (name "upower")
                            (group "upower")
                            (system? #t)
                            (comment "UPower daemon user")
                            (home-directory "/var/empty")
                            (shell
                             #~(string-append #$shadow "/sbin/nologin")))))))))


;;;
;;; Colord D-Bus service.
;;;

(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
                             #~(string-append #$shadow "/sbin/nologin")))))))))


;;;
;;; GeoClue D-Bus service.
;;;

(define* (geoclue-application name #:key (allowed? #t) system? (users '()))
  "Configure default GeoClue access permissions for an application.  NAME is
the Desktop ID of the application, without the .desktop part.  If ALLOWED? is
true, the application will have access to location information by default.
The boolean SYSTEM? value indicates that an application is a system component
or not.  Finally USERS is a list of UIDs of all users for which this
application is allowed location info access.  An empty users list means all
users are allowed."
  (string-append
   "[" name "]\n"
   "allowed=" (bool allowed?)
   "system=" (bool system?)
   "users=" (string-join users ";") "\n"))

(define %standard-geoclue-applications
  (list (geoclue-application "gnome-datetime-panel" #:system? #t)
        (geoclue-application "epiphany" #:system? #f)
        (geoclue-application "firefox" #:system? #f)))

(define* (geoclue-configuration-file #:key whitelist wifi-geolocation-url
                                     submit-data?
                                     wifi-submission-url submission-nick
                                     applications)
  "Return a geoclue configuration file."
  (text-file "geoclue.conf"
             (string-append
              "[agent]\n"
              "whitelist=" (string-join whitelist ";") "\n"
              "[wifi]\n"
              "url=" wifi-geolocation-url "\n"
              "submit-data=" (bool submit-data?)
              "submission-url=" wifi-submission-url "\n"
              "submission-nick=" submission-nick "\n"
              (string-join applications "\n"))))

(define* (geoclue-service #:key (geoclue geoclue)
                          (whitelist '())
                          (wifi-geolocation-url
                           ;; Mozilla geolocation service:
                           "https://location.services.mozilla.com/v1/geolocate?key=geoclue")
                          (submit-data? #f)
                          (wifi-submission-url
                           "https://location.services.mozilla.com/v1/submit?key=geoclue")
                          (submission-nick "geoclue")
                          (applications %standard-geoclue-applications))
  "Return a service that runs the @command{geoclue} location service.  This
service provides a D-Bus interface to allow applications to request access to
a user's physical location, and optionally to add information to online
location databases.  By default, only the GNOME date-time panel and the Icecat
and Epiphany web browsers are able to ask for the user's location, and in the
case of Icecat and Epiphany, both will ask the user for permission first.  See
@uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the geoclue web
site} for more information."
  (mlet %store-monad ((config (geoclue-configuration-file
                               #:whitelist whitelist
                               #:wifi-geolocation-url wifi-geolocation-url
                               #:submit-data? submit-data?
                               #:wifi-submission-url wifi-submission-url
                               #:submission-nick submission-nick
                               #:applications applications)))
    (return
     (service
      (documentation "Run the GeoClue location service.")
      (provision '(geoclue-daemon))
      (requirement '(dbus-system))

      (start #~(make-forkexec-constructor
                (list (string-append #$geoclue "/libexec/geoclue"))
                #:user "geoclue"
                #:environment-variables
                (list (string-append "GEOCLUE_CONFIG_FILE=" #$config))))
      (stop #~(make-kill-destructor))

      (user-groups (list (user-group
                          (name "geoclue")
                          (system? #t))))
      (user-accounts (list (user-account
                            (name "geoclue")
                            (group "geoclue")
                            (system? #t)
                            (comment "GeoClue daemon user")
                            (home-directory "/var/empty")
                            (shell
                             "/run/current-system/profile/sbin/nologin"))))))))


;;;
;;; The default set of desktop services.
;;;
(define %desktop-services
  ;; List of services typically useful for a "desktop" use case.
  (cons* (slim-service)

         (avahi-service)
         (wicd-service)
         (upower-service)
         ;; FIXME: The colord and geoclue services could all be bus-activated
         ;; by default, so they don't run at program startup.  However, user
         ;; creation and /var/lib.colord creation happen at service activation
         ;; time, so we currently add them to the set of default services.
         (colord-service)
         (geoclue-service)
         (dbus-service (list avahi wicd upower colord geoclue))

         (ntp-service)

         (map (lambda (mservice)
                ;; Provide an nscd ready to use nss-mdns.
                (mlet %store-monad ((service mservice))
                  (if (memq 'nscd (service-provision service))
                      (nscd-service (nscd-configuration)
                                    #:name-services (list nss-mdns))
                      mservice)))
              %base-services)))

;;; desktop.scm ends here
