services: dnsmasq: Install dbus config.

While DBUS service is enabled in dnsmasq, it does not work without installing
a config file to the system.

* gnu/packages/dns.scm (dnsmasq): Install dbus config.
* gnu/services/dns.scm (dnsmasq): Extend dbus-root-service-type.

Change-Id: I5187f65e1f2892eb10fb95e6f51955559f64dbef
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/dns.scm

@@ -310,7 +310,13 @@ prompt the user with the option to go with insecure DNS only.")
      (list dbus))
     (arguments
      `(#:phases
-       (modify-phases %standard-phases (delete 'configure))
+       (modify-phases %standard-phases
+         (delete 'configure)
+         (add-after 'install 'install-dbus
+           (lambda _
+             (install-file "dbus/dnsmasq.conf"
+                           (string-append %output "/etc/dbus-1/system.d")))))
+
        #:make-flags (list (string-append "PREFIX=" (assoc-ref %outputs "out"))
                           (string-append "CC=" ,(cc-for-target))
                           (string-append "PKG_CONFIG=" ,(pkg-config-for-target))

gnu/services/dns.scm

@@ -23,6 +23,7 @@
 (define-module (gnu services dns)
   #:use-module (gnu services)
   #:use-module (gnu services configuration)
+  #:use-module (gnu services dbus)
   #:use-module (gnu services shepherd)
   #:use-module (gnu system shadow)
   #:use-module (gnu packages admin)
@@ -993,6 +994,8 @@ log.")
    (extensions
     (list (service-extension shepherd-root-service-type
                              (compose list dnsmasq-shepherd-service))
+          (service-extension dbus-root-service-type
+                             (compose list dnsmasq-configuration-package))
           (service-extension activation-service-type
                              dnsmasq-activation)))
    (default-value (dnsmasq-configuration))