automount: port from CK to systemd-logind

ConsoleKit is being obsoleted by systemd. Accordingly port the CK logic
in the gnome-shell automount manager to systemd-logind APIs.

This makes use of systemd-logind's native C APIs which are much easier
to use than the D-Bus APIs in this case, and much faster too (since they
are synchronous and directly query the kernel for the information we
need). The dependency is compile time optional, and in order to be nice
to the Debian folks g-s compiled with this enabled fill automatically
fall back to CK support on systems lacking systemd.

configure.ac

@@ -141,6 +141,33 @@ PKG_CHECK_MODULES(CALENDAR_SERVER, libecal-1.2 >= $LIBECAL_MIN_VERSION libedatas
 AC_SUBST(CALENDAR_SERVER_CFLAGS)
 AC_SUBST(CALENDAR_SERVER_LIBS)
 
+AC_ARG_WITH(systemd,
+            AS_HELP_STRING([--with-systemd],
+                           [Add systemd support]),
+            [with_systemd=$withval], [with_systemd=auto])
+
+PKG_CHECK_MODULES(SYSTEMD,
+                  [libsystemd-login libsystemd-daemon],
+                  [have_systemd=yes], [have_systemd=no])
+
+if test "x$with_systemd" = "xauto" ; then
+        if test x$have_systemd = xno ; then
+                use_systemd=no
+        else
+                use_systemd=yes
+        fi
+else
+        use_systemd=$with_systemd
+fi
+
+if test "x$use_systemd" = "xyes"; then
+        if test "x$have_systemd" = "xno"; then
+                AC_MSG_ERROR([Systemd support explicitly required, but systemd not found])
+        fi
+
+        AC_DEFINE(WITH_SYSTEMD, 1, [systemd support])
+fi
+
 MUTTER_GIR_DIR=`$PKG_CONFIG --variable=girdir libmutter`
 MUTTER_TYPELIB_DIR=`$PKG_CONFIG --variable=typelibdir libmutter`
 AC_SUBST(MUTTER_GIR_DIR)

js/ui/automountManager.js

@@ -2,9 +2,11 @@
 
 const Lang = imports.lang;
 const Mainloop = imports.mainloop;
+const GLib = imports.gi.GLib;
 const Gio = imports.gi.Gio;
 const Params = imports.misc.params;
 
+const Shell = imports.gi.Shell;
 const Main = imports.ui.main;
 const ShellMountOperation = imports.ui.shellMountOperation;
 const ScreenSaver = imports.misc.screenSaver;
@@ -67,6 +69,10 @@ function ConsoleKitManager() {
     return self;
 }
 
+function haveSystemd() {
+    return GLib.access("/sys/fs/cgroup/systemd", 0) >= 0;
+}
+
 const AutomountManager = new Lang.Class({
     Name: 'AutomountManager',
 
@@ -74,7 +80,8 @@ const AutomountManager = new Lang.Class({
         this._settings = new Gio.Settings({ schema: SETTINGS_SCHEMA });
         this._volumeQueue = [];
 
-        this.ckListener = new ConsoleKitManager();
+        if (!haveSystemd())
+            this.ckListener = new ConsoleKitManager();
 
         this._ssProxy = new ScreenSaver.ScreenSaverProxy();
         this._ssProxy.connectSignal('ActiveChanged',
@@ -122,11 +129,22 @@ const AutomountManager = new Lang.Class({
         return false;
     },
 
+    _sessionActive: function() {
+        // Return whether the current session is active, using the
+        // right mechanism: either systemd if available or ConsoleKit
+        // as fallback.
+
+        if (haveSystemd())
+            return Shell.session_is_active_for_systemd();
+
+        return this.ckListener.sessionActive;
+    },
+
     _onDriveConnected: function() {
         // if we're not in the current ConsoleKit session,
         // or screensaver is active, don't play sounds
-        if (!this.ckListener.sessionActive)
-            return;        
+        if (!this._sessionActive())
+            return;
 
         if (this._ssProxy.screenSaverActive)
             return;
@@ -137,8 +155,8 @@ const AutomountManager = new Lang.Class({
     _onDriveDisconnected: function() {
         // if we're not in the current ConsoleKit session,
         // or screensaver is active, don't play sounds
-        if (!this.ckListener.sessionActive)
-            return;        
+        if (!this._sessionActive())
+            return;
 
         if (this._ssProxy.screenSaverActive)
             return;
@@ -149,7 +167,7 @@ const AutomountManager = new Lang.Class({
     _onDriveEjectButton: function(monitor, drive) {
         // TODO: this code path is not tested, as the GVfs volume monitor
         // doesn't emit this signal just yet.
-        if (!this.ckListener.sessionActive)
+        if (!this._sessionActive())
             return;
 
         // we force stop/eject in this case, so we don't have to pass a
@@ -188,7 +206,7 @@ const AutomountManager = new Lang.Class({
         if (params.checkSession) {
             // if we're not in the current ConsoleKit session,
             // don't attempt automount
-            if (!this.ckListener.sessionActive)
+            if (!this._sessionActive())
                 return;
 
             if (this._ssProxy.screenSaverActive) {

src/Makefile.am

@@ -81,6 +81,7 @@ include Makefile-hotplug-sniffer.am
 
 gnome_shell_cflags =				\
 	$(GNOME_SHELL_CFLAGS)			\
+	$(SYSTEMD_CFLAGS)                       \
 	-I$(srcdir)/tray			\
 	-DVERSION=\"$(VERSION)\"		\
 	-DLOCALEDIR=\"$(datadir)/locale\" 	\
@@ -279,6 +280,7 @@ libgnome_shell_la_LDFLAGS = -avoid-version
 libgnome_shell_la_LIBADD =		\
 	-lm			\
 	$(GNOME_SHELL_LIBS)	\
+	$(SYSTEMD_LIBS)         \
 	$(BLUETOOTH_LIBS)	\
 	libst-1.0.la       	\
 	libtray.la		\

src/shell-util.c

@@ -14,6 +14,11 @@
 #include <libxml/tree.h>
 #include <libxml/xmlmemory.h>
 
+#ifdef WITH_SYSTEMD
+#include <systemd/sd-daemon.h>
+#include <systemd/sd-login.h>
+#endif
+
 /* Some code in this file adapted under the GPLv2+ from:
  *
  * GNOME panel utils: gnome-panel/gnome-panel/panel-util.c
@@ -833,3 +838,26 @@ shell_shader_effect_set_double_uniform (ClutterShaderEffect *effect,
                                            name,
                                            &gvalue);
 }
+
+/**
+ * shell_session_is_active_for_systemd:
+ *
+ * Checks whether the session we are running in is currently active,
+ * i.e. in the foreground and ready for user input.
+ *
+ * Returns: TRUE if session is active
+ */
+gboolean
+shell_session_is_active_for_systemd (void)
+{
+  /* If this isn't systemd, let's assume the session is active. */
+
+#ifdef WITH_SYSTEMD
+  if (sd_booted () <= 0)
+    return TRUE;
+
+  return sd_session_is_active (NULL) != 0;
+#else
+  return TRUE;
+#endif
+}

src/shell-util.h

@@ -50,6 +50,8 @@ void shell_shader_effect_set_double_uniform (ClutterShaderEffect *effect,
                                              const gchar         *name,
                                              gdouble             value);
 
+gboolean shell_session_is_active_for_systemd (void);
+
 G_END_DECLS
 
 #endif /* __SHELL_UTIL_H__ */