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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
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