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+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.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 dbus)
+ #:use-module (gnu services)
+ #:use-module (gnu services dmd)
+ #:use-module (gnu system shadow)
+ #:use-module (gnu packages glib)
+ #:use-module (gnu packages admin)
+ #:use-module (guix gexp)
+ #:use-module (guix records)
+ #:use-module (srfi srfi-1)
+ #:use-module (ice-9 match)
+ #:export (dbus-root-service-type
+ dbus-service))
+
+;;;
+;;; D-Bus.
+;;;
+
+(define-record-type* <dbus-configuration>
+ dbus-configuration make-dbus-configuration
+ dbus-configuration?
+ (dbus dbus-configuration-dbus ;<package>
+ (default dbus))
+ (services dbus-configuration-services ;list of <package>
+ (default '())))
+
+(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"))
+ (servicedir ;likewise, for auto-activation
+ ,(string-append
+ dir
+ "/share/dbus-1/system-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)))))
+
+ (computed-file "dbus-configuration" build))
+
+(define %dbus-accounts
+ ;; Accounts used by the system bus.
+ (list (user-group (name "messagebus") (system? #t))
+ (user-account
+ (name "messagebus")
+ (group "messagebus")
+ (system? #t)
+ (comment "D-Bus system bus user")
+ (home-directory "/var/run/dbus")
+ (shell #~(string-append #$shadow "/sbin/nologin")))))
+
+(define (dbus-activation config)
+ "Return an activation gexp for D-Bus using @var{config}."
+ #~(begin
+ (use-modules (guix build utils))
+
+ (mkdir-p "/var/run/dbus")
+
+ (let ((user (getpwnam "messagebus")))
+ (chown "/var/run/dbus"
+ (passwd:uid user) (passwd:gid user)))
+
+ (unless (file-exists? "/etc/machine-id")
+ (format #t "creating /etc/machine-id...~%")
+ (let ((prog (string-append #$(dbus-configuration-dbus config)
+ "/bin/dbus-uuidgen")))
+ ;; XXX: We can't use 'system' because the initrd's
+ ;; guile system(3) only works when 'sh' is in $PATH.
+ (let ((pid (primitive-fork)))
+ (if (zero? pid)
+ (call-with-output-file "/etc/machine-id"
+ (lambda (port)
+ (close-fdes 1)
+ (dup2 (port->fdes port) 1)
+ (execl prog)))
+ (waitpid pid)))))))
+
+(define dbus-dmd-service
+ (match-lambda
+ (($ <dbus-configuration> dbus services)
+ (let ((conf (dbus-configuration-directory dbus services)))
+ (list (dmd-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))))))))
+
+(define dbus-root-service-type
+ (service-type (name 'dbus)
+ (extensions
+ (list (service-extension dmd-root-service-type
+ dbus-dmd-service)
+ (service-extension activation-service-type
+ dbus-activation)
+ (service-extension account-service-type
+ (const %dbus-accounts))))
+
+ ;; Extensions consist of lists of packages (representing D-Bus
+ ;; services) that we just concatenate.
+ ;;
+ ;; FIXME: We need 'dbus-daemon-launch-helper' to be
+ ;; setuid-root for auto-activation to work.
+ (compose concatenate)
+
+ ;; The service's parameters field is extended by augmenting
+ ;; its <dbus-configuration> 'services' field.
+ (extend (lambda (config services)
+ (dbus-configuration
+ (inherit config)
+ (services
+ (append (dbus-configuration-services config)
+ services)))))))
+
+(define* (dbus-service #:key (dbus dbus) (services '()))
+ "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)}."
+ (service dbus-root-service-type
+ (dbus-configuration (dbus dbus)
+ (services services))))
+
+;;; dbus.scm ends here