From b68f65007f50175a68cd174ad7c1036cf622556d Mon Sep 17 00:00:00 2001
From: Ludovic Courtès <ludo@gnu.org>
Date: Tue, 2 Apr 2019 21:36:26 +0200
Subject: services: dbus: Add 'wrapped-dbus-service'.

* gnu/services/desktop.scm (wrapped-dbus-service): Move to...
* gnu/services/dbus.scm (wrapped-dbus-service): ... here.  New
procedure.
---
 gnu/services/dbus.scm | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

(limited to 'gnu/services/dbus.scm')

diff --git a/gnu/services/dbus.scm b/gnu/services/dbus.scm
index 606ee0c2f5..3d2dbb903c 100644
--- a/gnu/services/dbus.scm
+++ b/gnu/services/dbus.scm
@@ -26,6 +26,7 @@
   #:use-module (gnu packages polkit)
   #:use-module (gnu packages admin)
   #:use-module (guix gexp)
+  #:use-module ((guix packages) #:select (package-name))
   #:use-module (guix records)
   #:use-module (srfi srfi-1)
   #:use-module (ice-9 match)
@@ -33,6 +34,7 @@
             dbus-configuration?
             dbus-root-service-type
             dbus-service
+            wrapped-dbus-service
 
             polkit-service-type
             polkit-service))
@@ -229,6 +231,46 @@ and policy files.  For example, to allow avahi-daemon to use the system bus,
            (dbus-configuration (dbus dbus)
                                (services services))))
 
+(define (wrapped-dbus-service service program variable value)
+  "Return a wrapper for @var{service}, a package containing a D-Bus service,
+where @var{program} is wrapped such that environment variable @var{variable}
+is set to @var{value} when the bus daemon launches it."
+  (define wrapper
+    (program-file (string-append (package-name service) "-program-wrapper")
+                  #~(begin
+                      (setenv #$variable #$value)
+                      (apply execl (string-append #$service "/" #$program)
+                             (string-append #$service "/" #$program)
+                             (cdr (command-line))))))
+
+  (define build
+    (with-imported-modules '((guix build utils))
+      #~(begin
+          (use-modules (guix build utils))
+
+          (define service-directory
+            "/share/dbus-1/system-services")
+
+          (mkdir-p (dirname (string-append #$output
+                                           service-directory)))
+          (copy-recursively (string-append #$service
+                                           service-directory)
+                            (string-append #$output
+                                           service-directory))
+          (symlink (string-append #$service "/etc") ;for etc/dbus-1
+                   (string-append #$output "/etc"))
+
+          (for-each (lambda (file)
+                      (substitute* file
+                        (("Exec[[:blank:]]*=[[:blank:]]*([[:graph:]]+)(.*)$"
+                          _ original-program arguments)
+                         (string-append "Exec=" #$wrapper arguments
+                                        "\n"))))
+                    (find-files #$output "\\.service$")))))
+
+  (computed-file (string-append (package-name service) "-wrapper")
+                 build))
+
 
 ;;;
 ;;; Polkit privilege management service.
-- 
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