Merge lp:~bratsche/indicator-session/users-service for bug #422052

9 files changed, 1517 insertions, 74 deletions

diff --git a/AUTHORS b/AUTHORS
index e69de29..a1771e3 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -0,0 +1,2 @@
+Ted Gould <ted@canonical.com>
+Cody Russell <crussell@canonical.com>
diff --git a/src/Makefile.am b/src/Makefile.am
index ae941e1..17d14e1 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -11,7 +11,8 @@ sessionlib_LTLIBRARIES = libsession.la
 libsession_la_SOURCES = \
 	indicator-session.c \
 	dbus-shared-names.h \
-	status-service-client.h
+	status-service-client.h \
+	users-service-client.h
 libsession_la_CFLAGS = $(APPLET_CFLAGS) -Wall -Werror
 libsession_la_LIBADD = $(APPLET_LIBS)
 libsession_la_LDFLAGS = -module -avoid-version
@@ -25,6 +26,10 @@ indicator_status_service_SOURCES = \
 	status-service-dbus.h \
 	status-service-dbus.c \
 	status-service-server.h \
+	users-service-dbus.h \
+	users-service-dbus.c \
+	users-service-marshal.c \
+	users-service-marshal.h \
 	status-provider.h \
 	status-provider.c \
 	status-provider-mc5.h \
@@ -42,6 +47,13 @@ indicator_status_service_SOURCES = \
 indicator_status_service_CFLAGS = $(STATUSSERVICE_CFLAGS) -Wall -Werror
 indicator_status_service_LDADD = $(STATUSSERVICE_LIBS)
 
+users-service-client.h: $(srcdir)/users-service.xml
+	dbus-binding-tool \
+		--prefix=_users_service_client \
+		--mode=glib-client \
+		--output=users-service-client.h \
+		$(srcdir)/users-service.xml
+
 status-service-client.h: $(srcdir)/status-service.xml
 	dbus-binding-tool \
 		--prefix=_status_service_client \
@@ -56,6 +68,16 @@ status-service-server.h: $(srcdir)/status-service.xml
 		--output=status-service-server.h \
 		$(srcdir)/status-service.xml
 
+users-service-marshal.h: $(srcdir)/users-service.list
+	glib-genmarshal --header \
+		--prefix=_users_service_marshal $(srcdir)/users-service.list \
+		> users-service-marshal.h
+
+users-service-marshal.c: $(srcdir)/users-service.list
+	glib-genmarshal --body \
+		--prefix=_users_service_marshal $(srcdir)/users-service.list \
+		> users-service-marshal.c
+
 status-provider-pidgin-marshal.h: $(srcdir)/status-provider-pidgin.list
 	glib-genmarshal --header \
 		--prefix=_status_provider_pidgin_marshal $(srcdir)/status-provider-pidgin.list \
@@ -90,7 +112,7 @@ status-provider-mc5-marshal.c: $(srcdir)/status-provider-mc5.list
 # Users Stuff
 ###############
 
-indicator_users_service_SOURCES = users-service.c
+indicator_users_service_SOURCES = users-service.c users-service-dbus.c users-service-marshal.c
 indicator_users_service_CFLAGS = $(USERSSERVICE_CFLAGS) -Wall -Werror
 indicator_users_service_LDADD = $(USERSSERVICE_LIBS)
 
@@ -107,10 +129,13 @@ indicator_session_service_LDADD = $(SESSIONSERVICE_LIBS) $(GCONF_LIBS)
 ###############
 
 BUILT_SOURCES = \
+	users-service-client.h \
 	status-service-client.h \
 	status-service-server.h \
 	status-provider-mc5-marshal.h \
 	status-provider-mc5-marshal.c \
+	users-service-marshal.h \
+	users-service-marshal.c \
 	status-provider-pidgin-marshal.h \
 	status-provider-pidgin-marshal.c \
 	status-provider-telepathy-marshal.h \
diff --git a/src/dbus-shared-names.h b/src/dbus-shared-names.h
index a645830..7e7d456 100644
--- a/src/dbus-shared-names.h
+++ b/src/dbus-shared-names.h
@@ -7,16 +7,16 @@ Copyright 2009 Canonical Ltd.
 Authors:
     Ted Gould <ted@canonical.com>
 
-This program is free software: you can redistribute it and/or modify it 
-under the terms of the GNU General Public License version 3, as published 
+This program is free software: you can redistribute it and/or modify it
+under the terms of the GNU General Public License version 3, as published
 by the Free Software Foundation.
 
-This program is distributed in the hope that it will be useful, but 
-WITHOUT ANY WARRANTY; without even the implied warranties of 
-MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR 
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranties of
+MERCHANTABILITY, SATISFACTORY QUALITY, 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 
+You should have received a copy of the GNU General Public License along
 with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
@@ -31,6 +31,8 @@ with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #define INDICATOR_USERS_DBUS_NAME  "org.ayatana.indicator.users"
 #define INDICATOR_USERS_DBUS_OBJECT "/org/ayatana/indicator/users/menu"
+#define INDICATOR_USERS_SERVICE_DBUS_OBJECT "/org/gnome/DisplayManager/UserManager"
+#define INDICATOR_USERS_SERVICE_DBUS_INTERFACE "org.gnome.DisplayManager.UserManager"
 
 #define INDICATOR_SESSION_DBUS_NAME  "org.ayatana.indicator.session"
 #define INDICATOR_SESSION_DBUS_OBJECT "/org/ayatana/indicator/session/menu"
diff --git a/src/status-service.c b/src/status-service.c
index d8b3631..a448ada 100644
--- a/src/status-service.c
+++ b/src/status-service.c
@@ -7,16 +7,16 @@ Copyright 2009 Canonical Ltd.
 Authors:
     Ted Gould <ted@canonical.com>
 
-This program is free software: you can redistribute it and/or modify it 
-under the terms of the GNU General Public License version 3, as published 
+This program is free software: you can redistribute it and/or modify it
+under the terms of the GNU General Public License version 3, as published
 by the Free Software Foundation.
 
-This program is distributed in the hope that it will be useful, but 
-WITHOUT ANY WARRANTY; without even the implied warranties of 
-MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR 
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranties of
+MERCHANTABILITY, SATISFACTORY QUALITY, 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 
+You should have received a copy of the GNU General Public License along
 with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
@@ -240,12 +240,12 @@ main (int argc, char ** argv)
     if (!org_freedesktop_DBus_request_name(bus_proxy, INDICATOR_STATUS_DBUS_NAME, 0, &nameret, &error)) {
         g_error("Unable to call to request name");
         return 1;
-    }   
+    }
 
     if (nameret != DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER) {
         g_error("Unable to get name");
         return 1;
-    }   
+    }
 
 	g_idle_add(build_providers, NULL);
 
diff --git a/src/users-service-dbus.c b/src/users-service-dbus.c
new file mode 100644
index 0000000..018469c
--- /dev/null
+++ b/src/users-service-dbus.c
@@ -0,0 +1,1147 @@
+/*
+ * Copyright 2009 Canonical Ltd.
+ *
+ * Authors:
+ *     Cody Russell <crussell@canonical.com>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <string.h>
+#include <errno.h>
+#include <pwd.h>
+
+#include <dbus/dbus-glib.h>
+#include <dbus/dbus-glib.h>
+#include <dbus/dbus-glib-lowlevel.h>
+
+#include "dbus-shared-names.h"
+#include "users-service-dbus.h"
+#include "users-service-client.h"
+#include "users-service-marshal.h"
+
+static void     users_service_dbus_class_init         (UsersServiceDbusClass *klass);
+static void     users_service_dbus_init               (UsersServiceDbus  *self);
+static void     users_service_dbus_dispose            (GObject           *object);
+static void     users_service_dbus_finalize           (GObject           *object);
+static void     create_gdm_proxy                       (UsersServiceDbus  *self);
+static void     create_seat_proxy                      (UsersServiceDbus  *self);
+static void     create_ck_proxy                        (UsersServiceDbus *self);
+static void     create_cksession_proxy                 (UsersServiceDbus *self);
+static gchar   *get_seat                               (UsersServiceDbus *service);
+static void     users_loaded                           (DBusGProxy        *proxy,
+                                                        gpointer           user_data);
+static void     user_added                             (DBusGProxy        *proxy,
+                                                        guint              uid,
+                                                        gpointer           user_data);
+static void     user_removed                           (DBusGProxy        *proxy,
+                                                        guint              uid,
+                                                        gpointer           user_data);
+static void     user_updated                           (DBusGProxy        *proxy,
+                                                        guint              uid,
+                                                        gpointer           user_data);
+static void     seat_proxy_session_added               (DBusGProxy        *seat_proxy,
+                                                        const gchar       *session_id,
+                                                        UsersServiceDbus  *service);
+static void     seat_proxy_session_removed             (DBusGProxy        *seat_proxy,
+                                                        const gchar       *session_id,
+                                                        UsersServiceDbus  *service);
+static gboolean do_add_session                         (UsersServiceDbus  *service,
+                                                        UserData          *user,
+                                                        const gchar       *ssid);
+static gchar *  get_seat_internal                      (UsersServiceDbus  *self);
+
+/* Private */
+typedef struct _UsersServiceDbusPrivate UsersServiceDbusPrivate;
+
+struct _UsersServiceDbusPrivate
+{
+  GHashTable *users;
+  gint        count;
+  gchar      *seat;
+  gchar      *ssid;
+
+  DBusGConnection *system_bus;
+
+  DBusGProxy *gdm_proxy;
+  DBusGProxy *ck_proxy;
+  DBusGProxy *seat_proxy;
+  DBusGProxy *session_proxy;
+
+  GHashTable *exclusions;
+  GHashTable *sessions;
+};
+
+#define USERS_SERVICE_DBUS_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), USERS_SERVICE_DBUS_TYPE, UsersServiceDbusPrivate))
+
+/* Signals */
+enum {
+  USERS_LOADED,
+  USER_ADDED,
+  USER_REMOVED,
+  USER_UPDATED,
+  LAST_SIGNAL
+};
+
+static guint signals[LAST_SIGNAL] = { 0 };
+
+/* GObject Boilerplate */
+G_DEFINE_TYPE (UsersServiceDbus, users_service_dbus, G_TYPE_OBJECT);
+
+static void
+users_service_dbus_class_init (UsersServiceDbusClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  g_type_class_add_private (object_class, sizeof (UsersServiceDbusPrivate));
+
+  object_class->dispose = users_service_dbus_dispose;
+  object_class->finalize = users_service_dbus_finalize;
+
+  signals[USERS_LOADED] = g_signal_new ("users-loaded",
+                                        G_TYPE_FROM_CLASS (klass),
+                                        G_SIGNAL_RUN_LAST,
+                                        G_STRUCT_OFFSET (UsersServiceDbusClass, users_loaded),
+                                        NULL, NULL,
+                                        g_cclosure_marshal_VOID__VOID,
+                                        G_TYPE_NONE, 0);
+
+  signals[USER_ADDED] = g_signal_new ("user-added",
+                                      G_TYPE_FROM_CLASS (klass),
+                                      G_SIGNAL_RUN_LAST,
+                                      G_STRUCT_OFFSET (UsersServiceDbusClass, user_added),
+                                      NULL, NULL,
+                                      _users_service_marshal_VOID__INT64,
+                                      G_TYPE_NONE, 1, G_TYPE_INT64);
+
+  signals[USER_REMOVED] = g_signal_new ("user-removed",
+                                        G_TYPE_FROM_CLASS (klass),
+                                        G_SIGNAL_RUN_LAST,
+                                        G_STRUCT_OFFSET (UsersServiceDbusClass, user_removed),
+                                        NULL, NULL,
+                                        _users_service_marshal_VOID__INT64,
+                                        G_TYPE_NONE, 1, G_TYPE_INT64);
+
+  signals[USER_UPDATED] = g_signal_new ("user-updated",
+                                        G_TYPE_FROM_CLASS (klass),
+                                        G_SIGNAL_RUN_LAST,
+                                        G_STRUCT_OFFSET (UsersServiceDbusClass, user_updated),
+                                        NULL, NULL,
+                                        _users_service_marshal_VOID__INT64,
+                                        G_TYPE_NONE, 1, G_TYPE_INT64);
+}
+
+static void
+users_service_dbus_init (UsersServiceDbus *self)
+{
+  GError *error = NULL;
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+
+  priv->users = NULL;
+  priv->count = 0;
+
+  /* Get the system bus */
+  priv->system_bus = dbus_g_bus_get (DBUS_BUS_SYSTEM, &error);
+  if (error != NULL)
+    {
+      g_error ("Unable to get system bus: %s", error->message);
+      g_error_free(error);
+
+      return;
+    }
+
+  priv->sessions = g_hash_table_new_full (g_str_hash,
+                                          g_str_equal,
+                                          g_free,
+                                          g_free);
+
+  priv->users = g_hash_table_new_full (g_str_hash,
+                                       g_str_equal,
+                                       g_free,
+                                       NULL);
+
+  dbus_g_object_register_marshaller (_users_service_marshal_VOID__INT64,
+                                     G_TYPE_NONE,
+                                     G_TYPE_INT64,
+                                     G_TYPE_INVALID);
+
+  create_gdm_proxy (self);
+  create_ck_proxy (self);
+  create_seat_proxy (self);
+
+  users_loaded (priv->gdm_proxy, self);
+}
+
+static void
+users_service_dbus_dispose (GObject *object)
+{
+  G_OBJECT_CLASS (users_service_dbus_parent_class)->dispose (object);
+}
+
+static void
+users_service_dbus_finalize (GObject *object)
+{
+  G_OBJECT_CLASS (users_service_dbus_parent_class)->finalize (object);
+}
+
+static void
+create_gdm_proxy (UsersServiceDbus *self)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  GError *error = NULL;
+
+  priv->gdm_proxy = dbus_g_proxy_new_for_name_owner (priv->system_bus,
+                                                     "org.gnome.DisplayManager",
+                                                     "/org/gnome/DisplayManager/UserManager",
+                                                     "org.gnome.DisplayManager.UserManager",
+                                                     &error);
+
+  if (!priv->gdm_proxy)
+    {
+      if (error != NULL)
+        {
+          g_error ("Unable to get DisplayManager proxy on system bus: %s", error->message);
+          g_error_free (error);
+        }
+
+      return;
+    }
+
+  dbus_g_proxy_add_signal (priv->gdm_proxy,
+                           "UsersLoaded",
+                           G_TYPE_INVALID);
+
+  dbus_g_proxy_add_signal (priv->gdm_proxy,
+                           "UserAdded",
+                           G_TYPE_INT64,
+                           G_TYPE_INVALID);
+
+  dbus_g_proxy_add_signal (priv->gdm_proxy,
+                           "UserRemoved",
+                           G_TYPE_INT64,
+                           G_TYPE_INVALID);
+
+  dbus_g_proxy_add_signal (priv->gdm_proxy,
+                           "UserUpdated",
+                           G_TYPE_INT64,
+                           G_TYPE_INVALID);
+
+  dbus_g_proxy_connect_signal (priv->gdm_proxy,
+                               "UsersLoaded",
+                               G_CALLBACK (users_loaded),
+                               self,
+                               NULL);
+
+  dbus_g_proxy_connect_signal (priv->gdm_proxy,
+                               "UserAdded",
+                               G_CALLBACK (user_added),
+                               self,
+                               NULL);
+
+  dbus_g_proxy_connect_signal (priv->gdm_proxy,
+                               "UserRemoved",
+                               G_CALLBACK (user_removed),
+                               self,
+                               NULL);
+
+  dbus_g_proxy_connect_signal (priv->gdm_proxy,
+                               "UserUpdated",
+                               G_CALLBACK (user_updated),
+                               self,
+                               NULL);
+}
+
+static void
+create_ck_proxy (UsersServiceDbus *self)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+
+  priv->ck_proxy = dbus_g_proxy_new_for_name (priv->system_bus,
+                                              "org.freedesktop.ConsoleKit",
+                                              "/org/freedesktop/ConsoleKit/Manager",
+                                              "org.freedesktop.ConsoleKit.Manager");
+
+  if (!priv->ck_proxy)
+    {
+      g_warning ("Failed to get ConsoleKit proxy.");
+      return;
+    }
+}
+
+static void
+create_seat_proxy (UsersServiceDbus *self)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  GError *error = NULL;
+
+  priv->seat = get_seat (self);
+  if (priv->seat == NULL)
+    {
+      return;
+    }
+
+  priv->seat_proxy = dbus_g_proxy_new_for_name_owner (priv->system_bus,
+                                                      "org.freedesktop.ConsoleKit",
+                                                      priv->seat,
+                                                      "org.freedesktop.ConsoleKit.Seat",
+                                                      &error);
+
+  if (!priv->seat_proxy)
+    {
+      if (error != NULL)
+        {
+          g_warning ("Failed to connect to the ConsoleKit seat: %s", error->message);
+          g_error_free (error);
+        }
+
+      return;
+    }
+
+  dbus_g_proxy_add_signal (priv->seat_proxy,
+                           "SessionAdded",
+                           DBUS_TYPE_G_OBJECT_PATH,
+                           G_TYPE_INVALID);
+  dbus_g_proxy_add_signal (priv->seat_proxy,
+                           "SessionRemoved",
+                           DBUS_TYPE_G_OBJECT_PATH,
+                           G_TYPE_INVALID);
+
+  dbus_g_proxy_connect_signal (priv->seat_proxy,
+                               "SessionAdded",
+                               G_CALLBACK (seat_proxy_session_added),
+                               self,
+                               NULL);
+  dbus_g_proxy_connect_signal (priv->seat_proxy,
+                               "SessionRemoved",
+                               G_CALLBACK (seat_proxy_session_removed),
+                               self,
+                               NULL);
+}
+
+static void
+create_cksession_proxy (UsersServiceDbus *service)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+
+  priv->session_proxy = dbus_g_proxy_new_for_name (priv->system_bus,
+                                                   "org.freedesktop.ConsoleKit",
+                                                   priv->ssid,
+                                                   "org.freedesktop.ConsoleKit.Session");
+
+  if (!priv->session_proxy)
+    {
+      g_warning ("Failed to get ConsoleKit session proxy");
+      return;
+    }
+}
+
+static gchar *
+get_seat (UsersServiceDbus *service)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+  GError     *error = NULL;
+  gchar      *ssid = NULL;
+  gchar      *seat;
+
+  if (!dbus_g_proxy_call (priv->ck_proxy,
+                          "GetCurrentSession",
+                          &error,
+                          G_TYPE_INVALID,
+                          DBUS_TYPE_G_OBJECT_PATH,
+                          &ssid,
+                          G_TYPE_INVALID))
+    {
+      if (error)
+        {
+          g_debug ("Failed to call GetCurrentSession: %s", error->message);
+          g_error_free (error);
+        }
+
+      if (ssid)
+        g_free (ssid);
+
+      return NULL;
+    }
+
+  priv->ssid = ssid;
+  create_cksession_proxy (service);
+
+  seat = get_seat_internal (service);
+
+  return seat;
+}
+
+static gchar *
+get_seat_internal (UsersServiceDbus *self)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  GError *error = NULL;
+  gchar *seat = NULL;
+
+  if (!dbus_g_proxy_call (priv->session_proxy,
+                          "GetSeatId",
+                          &error,
+                          G_TYPE_INVALID,
+                          DBUS_TYPE_G_OBJECT_PATH, &seat,
+                          G_TYPE_INVALID))
+    {
+      if (error)
+        {
+          g_debug ("Failed to call GetSeatId: %s", error->message);
+
+          return NULL;
+        }
+    }
+
+  return seat;
+}
+
+static gboolean
+get_unix_user (UsersServiceDbus *service,
+               const gchar      *session_id,
+               uid_t            *uidp)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+  GError     *error = NULL;
+  guint       uid;
+
+  if (dbus_g_proxy_call (priv->session_proxy,
+                         "GetUnixUser",
+                         &error,
+                         G_TYPE_INVALID,
+                         G_TYPE_UINT, &uid,
+                         G_TYPE_INVALID))
+    {
+      if (error)
+        {
+          g_warning ("Failed to call GetUnixUser: %s", error->message);
+          g_error_free (error);
+        }
+
+      return FALSE;
+    }
+
+  if (uidp != NULL)
+    {
+      *uidp = (uid_t)uid;
+    }
+
+  return TRUE;
+}
+
+static gchar *
+get_session_for_user (UsersServiceDbus *service,
+                      UserData         *user)
+{
+  GList *l;
+
+  if (!users_service_dbus_can_activate_session (service))
+    {
+      return NULL;
+    }
+
+  if (!user->sessions || g_list_length (user->sessions) == 0)
+    {
+      return NULL;
+    }
+
+  for (l = user->sessions; l != NULL; l = l->next)
+    {
+      const char *ssid;
+
+      ssid = l->data;
+
+      if (ssid)
+        {
+          return g_strdup (ssid);
+        }
+    }
+
+  return NULL;
+}
+
+static gboolean
+do_add_session (UsersServiceDbus *service,
+                UserData         *user,
+                const gchar      *ssid)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+  GError *error = NULL;
+  gchar *seat = NULL;
+  gchar *xdisplay = NULL;
+  GList *l;
+
+  seat = get_seat_internal (service);
+
+  if (!seat || !priv->seat || strcmp (seat, priv->seat) != 0)
+    return FALSE;
+
+   if (!dbus_g_proxy_call (priv->session_proxy,
+                          "GetX11Display",
+                          &error,
+                          G_TYPE_INVALID,
+                          G_TYPE_STRING, &xdisplay,
+                          G_TYPE_INVALID))
+    {
+      if (error)
+        {
+          g_debug ("Failed to call GetX11Display: %s", error->message);
+          g_error_free (error);
+        }
+
+      return FALSE;
+    }
+
+  if (!xdisplay || xdisplay[0] == '\0')
+    return FALSE;
+
+  g_hash_table_insert (priv->sessions,
+                       g_strdup (ssid),
+                       g_strdup (user->user_name));
+
+  l = g_list_find_custom (user->sessions, ssid, (GCompareFunc)g_strcmp0);
+  if (l == NULL)
+    {
+      g_debug ("Adding session %s", ssid);
+
+      user->sessions = g_list_prepend (user->sessions, g_strdup (ssid));
+    }
+  else
+    {
+      g_debug ("User %s already has session %s", user->user_name, ssid);
+    }
+
+  return TRUE;
+}
+
+static void
+add_sessions_for_user (UsersServiceDbus *self,
+                       UserData         *user)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  GError          *error;
+  GPtrArray       *sessions;
+  int              i;
+
+  error = NULL;
+  if (!dbus_g_proxy_call (priv->ck_proxy,
+                          "GetSessionsForUnixUser",
+                          &error,
+                          G_TYPE_UINT, user->uid,
+                          G_TYPE_INVALID,
+                          dbus_g_type_get_collection ("GPtrArray", DBUS_TYPE_G_OBJECT_PATH),
+                          &sessions,
+                          G_TYPE_INVALID))
+    {
+      g_debug ("Failed to call GetSessionsForUnixUser: %s", error->message);
+      g_error_free (error);
+
+      return;
+    }
+
+  for (i = 0; i < sessions->len; i++)
+    {
+      char *ssid;
+
+      ssid = g_ptr_array_index (sessions, i);
+      do_add_session (self, user, ssid);
+    }
+
+  g_ptr_array_foreach (sessions, (GFunc)g_free, NULL);
+  g_ptr_array_free (sessions, TRUE);
+}
+
+
+static void
+seat_proxy_session_added (DBusGProxy       *seat_proxy,
+                          const gchar      *session_id,
+                          UsersServiceDbus *service)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+  uid_t          uid;
+  gboolean       res;
+  struct passwd *pwent;
+  UserData      *user;
+
+  if (!get_unix_user (service, session_id, &uid))
+    {
+      g_warning ("Failed to lookup user for session");
+      return;
+    }
+
+  errno = 0;
+  pwent = getpwuid (uid);
+  if (!pwent)
+    {
+      g_warning ("Failed to lookup user id %d: %s", (int)uid, g_strerror (errno));
+      return;
+    }
+
+  user = g_hash_table_lookup (priv->users, pwent->pw_name);
+  if (!user)
+    {
+      return;
+    }
+
+  res = do_add_session (service, user, session_id);
+}
+
+static void
+seat_proxy_session_removed (DBusGProxy       *seat_proxy,
+                            const gchar      *session_id,
+                            UsersServiceDbus *service)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+  UserData *user;
+  gchar    *username;
+  GList    *l;
+
+  username = g_hash_table_lookup (priv->sessions, session_id);
+  if (!username)
+    return;
+
+  user = g_hash_table_lookup (priv->users, username);
+  if (!user)
+    return;
+
+  l = g_list_find_custom (user->sessions,
+                          session_id,
+                          (GCompareFunc)g_strcmp0);
+  if (l)
+    {
+      g_debug ("Removing session %s", session_id);
+
+      g_free (l->data);
+      user->sessions = g_list_delete_link (user->sessions, l);
+    }
+  else
+    {
+      g_debug ("Session not found: %s", session_id);
+    }
+}
+
+static void
+sync_users (UsersServiceDbus *self)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+
+  if (g_hash_table_size (priv->users) > 0)
+    {
+      return;
+    }
+
+  if (priv->count > MINIMUM_USERS && priv->count < MAXIMUM_USERS)
+    {
+      GArray *uids = NULL;
+      GPtrArray *users_info = NULL;
+      GError *error = NULL;
+      gint i;
+
+      uids = g_array_new (FALSE, FALSE, sizeof (gint64));
+
+      if (!org_gnome_DisplayManager_UserManager_get_user_list (priv->gdm_proxy,
+                                                               &uids,
+                                                               &error))
+        {
+          g_warning ("failed to retrieve user list: %s", error->message);
+          g_error_free (error);
+
+          return;
+        }
+
+      users_info = g_ptr_array_new ();
+
+      if (!org_gnome_DisplayManager_UserManager_get_users_info (priv->gdm_proxy,
+                                                                uids,
+                                                                &users_info,
+                                                                &error))
+        {
+          g_warning ("failed to retrieve user info: %s", error->message);
+          g_error_free (error);
+
+          return;
+        }
+
+      for (i = 0; i < users_info->len; i++)
+        {
+          GValueArray *values;
+          UserData *user;
+
+          values = g_ptr_array_index (users_info, i);
+
+          user = g_new0 (UserData, 1);
+
+          user->uid         = g_value_get_int64  (g_value_array_get_nth (values, 0));
+          user->user_name   = g_strdup (g_value_get_string (g_value_array_get_nth (values, 1)));
+          user->real_name   = g_strdup (g_value_get_string (g_value_array_get_nth (values, 2)));
+          user->shell       = g_strdup (g_value_get_string (g_value_array_get_nth (values, 3)));
+          user->login_count = g_value_get_int    (g_value_array_get_nth (values, 4));
+          user->icon_url    = g_strdup (g_value_get_string (g_value_array_get_nth (values, 5)));
+
+          g_hash_table_insert (priv->users,
+                               g_strdup (user->user_name),
+                               user);
+
+          add_sessions_for_user (self, user);
+        }
+    }
+}
+
+static void
+users_loaded (DBusGProxy *proxy,
+              gpointer    user_data)
+{
+  UsersServiceDbus        *service;
+  UsersServiceDbusPrivate *priv;
+  GError                  *error = NULL;
+  gint                     count;
+
+  service = (UsersServiceDbus *)user_data;
+  priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+
+  if (!org_gnome_DisplayManager_UserManager_count_users (proxy,
+                                                         &count,
+                                                         &error))
+    {
+      g_warning ("failed to retrieve user count: %s", error->message);
+      g_error_free (error);
+
+      return;
+    }
+
+  priv->count = count;
+
+  sync_users (service);
+}
+
+static gboolean
+session_is_login_window (UsersServiceDbus *self,
+                         const char       *ssid)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  DBusGProxy *proxy = NULL;
+  GError     *error = NULL;
+  char       *type = NULL;
+
+  if (!(proxy = dbus_g_proxy_new_for_name (priv->system_bus,
+                                           "org.freedesktop.ConsoleKit",
+                                           ssid,
+                                           "org.freedesktop.ConsoleKit.Session")))
+    {
+      g_warning ("Failed to get ConsoleKit proxy");
+
+      return FALSE;
+    }
+
+  if (!dbus_g_proxy_call (proxy,
+                          "GetSessionType",
+                          &error,
+                          G_TYPE_INVALID,
+                          G_TYPE_STRING, &type,
+                          G_TYPE_INVALID))
+    {
+      g_warning ("Can't call GetSessionType: %s", error->message);
+      g_error_free (error);
+
+      if (proxy)
+        g_object_unref (proxy);
+
+      return FALSE;
+    }
+
+  if (proxy)
+    g_object_unref (proxy);
+
+  return (type && type[0] != '\0' && strcmp (type, "LoginWindow") == 0);
+}
+
+static char *
+get_login_session (UsersServiceDbus *self)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  gboolean    can_activate;
+  GError     *error = NULL;
+  GPtrArray  *sessions = NULL;
+  char       *ssid = NULL;
+  int         i;
+
+  if (!priv->seat || priv->seat[0] == '\0')
+    {
+      return NULL;
+    }
+
+  if (!dbus_g_proxy_call (priv->seat_proxy,
+                          "CanActivateSessions",
+                          &error,
+                          G_TYPE_INVALID,
+                          G_TYPE_BOOLEAN, &can_activate,
+                          G_TYPE_INVALID))
+    {
+      g_warning ("Failed to call CanActivateSessions: %s", error->message);
+      g_error_free (error);
+
+      return NULL;
+    }
+
+  if (!can_activate)
+    {
+      return NULL;
+    }
+
+  error = NULL;
+  if (!dbus_g_proxy_call (priv->seat_proxy,
+                          "GetSessions",
+                          &error,
+                          G_TYPE_INVALID,
+                          dbus_g_type_get_collection ("GPtrArray", DBUS_TYPE_G_OBJECT_PATH), &sessions,
+                          G_TYPE_INVALID))
+    {
+      g_warning ("Failed to call GetSessions: %s", error->message);
+      g_error_free (error);
+
+      return NULL;
+  }
+
+  for (i = 0; i < sessions->len; i++)
+    {
+      char *s = g_ptr_array_index (sessions, i);
+
+      if (session_is_login_window (self, s))
+        {
+          ssid = g_strdup (s);
+          break;
+        }
+    }
+
+  g_ptr_array_foreach (sessions, (GFunc)g_free, NULL);
+  g_ptr_array_free (sessions, TRUE);
+
+  return ssid;
+}
+
+static gboolean
+activate_user_session (UsersServiceDbus *self,
+                       const char       *seat,
+                       const char       *ssid)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  DBusMessage *message = NULL;
+  DBusMessage *reply   = NULL;
+  DBusError    error;
+
+  if (!(message = dbus_message_new_method_call ("org.freedesktop.ConsoleKit",
+                                                seat,
+                                                "org.freedesktop.ConsoleKit.Seat",
+                                                "ActivateSession")))
+    {
+      return FALSE;
+    }
+
+  if (!dbus_message_append_args (message,
+                                 DBUS_TYPE_OBJECT_PATH, &ssid,
+                                 DBUS_TYPE_INVALID))
+    {
+      return FALSE;
+    }
+
+  dbus_error_init (&error);
+  if (!(reply = dbus_connection_send_with_reply_and_block (dbus_g_connection_get_connection (priv->system_bus),
+                                                           message,
+                                                           -1,
+                                                           &error)))
+    {
+      if (dbus_error_is_set (&error))
+        {
+          g_warning ("Can't activate session: %s", error.message);
+          dbus_error_free (&error);
+
+          return FALSE;
+        }
+    }
+
+  if (message)
+    {
+      dbus_message_unref (message);
+    }
+
+  if (reply)
+    {
+      dbus_message_unref (reply);
+    }
+
+  return TRUE;
+}
+
+gboolean
+start_new_user_session (UsersServiceDbus *self,
+                        UserData         *user)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  GError   *error = NULL;
+  char     *ssid;
+
+  ssid = get_login_session (self);
+  if (ssid)
+    {
+      if (!activate_user_session (self, priv->seat, ssid))
+        {
+          return FALSE;
+        }
+    }
+
+  if (!g_spawn_command_line_async ("gdmflexiserver -s", &error))
+    {
+      g_warning ("Failed to start new login session: %s", error->message);
+      g_error_free (error);
+
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
+static void
+user_added (DBusGProxy *proxy,
+            guint       uid,
+            gpointer    user_data)
+{
+  UsersServiceDbus *service = (UsersServiceDbus *)user_data;
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+  UserData *user = g_new0 (UserData, 1);
+  GError *error = NULL;
+
+  priv->count++;
+
+  if (priv->count < MAXIMUM_USERS)
+    {
+      if ((priv->count - g_hash_table_size (priv->users)) > 1)
+        {
+          sync_users (service);
+        }
+      else
+        {
+          if (!org_gnome_DisplayManager_UserManager_get_user_info (proxy,
+                                                                   uid,
+                                                                   &user->user_name,
+                                                                   &user->real_name,
+                                                                   &user->shell,
+                                                                   &user->login_count,
+                                                                   &user->icon_url,
+                                                                   &error))
+            {
+              g_warning ("unable to retrieve user info: %s", error->message);
+              g_error_free (error);
+
+              g_free (user);
+
+              return;
+            }
+
+          user->uid = uid;
+
+          g_hash_table_insert (priv->users,
+                               g_strdup (user->user_name),
+                               user);
+
+          g_signal_emit (G_OBJECT (service), signals[USER_ADDED], 0, user, TRUE);
+        }
+    }
+}
+
+static gboolean
+compare_users_by_uid (gpointer key,
+                      gpointer value,
+                      gpointer user_data)
+{
+  return (GPOINTER_TO_UINT (value) == GPOINTER_TO_UINT (user_data));
+}
+
+static void
+user_removed (DBusGProxy *proxy,
+              guint       uid,
+              gpointer    user_data)
+{
+  UsersServiceDbus *service = (UsersServiceDbus *)user_data;
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+  UserData *user;
+  gint size;
+
+  size = g_hash_table_size (priv->users);
+
+  priv->count--;
+
+  if (size == 0 || (size - priv->count) > 1)
+    {
+      sync_users (service);
+    }
+  else
+    {
+      user = g_hash_table_find (priv->users,
+                                compare_users_by_uid,
+                                GUINT_TO_POINTER (uid));
+
+      if (user != NULL)
+        {
+          g_hash_table_remove (priv->users,
+                               user->user_name);
+        }
+    }
+}
+
+static void
+user_updated (DBusGProxy *proxy,
+              guint       uid,
+              gpointer    user_data)
+{
+#if 0
+  // XXX - TODO
+  UsersServiceDbus *service = (UsersServiceDbus *)user_data;
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (service);
+  UserData *user;
+
+  user = g_hash_table_find (priv->users,
+                            compare_users_by_uid,
+                            GUINT_TO_POINTER (uid));
+#endif
+}
+
+gint
+users_service_dbus_get_user_count (UsersServiceDbus *self)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+
+  return priv->count;
+}
+
+GList *
+users_service_dbus_get_user_list (UsersServiceDbus *self)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+
+  return g_hash_table_get_values (priv->users);
+}
+
+/*
+ * XXX - TODO: Right now we switch to a session that another user
+ *             already has open, but if there are no open sessions
+ *             for this user we go to the login screen and the
+ *             user at the seat must select a user and enter a
+ *             password.  This kind of defeats the purpose of
+ *             actually selecting a username, since selecting any
+ *             user will do the same thing here.  We need to change
+ *             it so you only need to enter a password for the
+ *             specified user.
+ */
+gboolean
+users_service_dbus_activate_user_session (UsersServiceDbus *self,
+                                          UserData         *user)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  DBusMessage *message = NULL;
+  DBusMessage *reply = NULL;
+  DBusError error;
+  gchar *ssid;
+
+  dbus_error_init (&error);
+
+  if (!priv->seat)
+    priv->seat = get_seat (self);
+
+  ssid = get_session_for_user (self, user);
+
+  if (!ssid)
+    {
+      return start_new_user_session (self, user);
+    }
+
+  if (!(message = dbus_message_new_method_call ("org.freedesktop.ConsoleKit",
+                                                priv->seat,
+                                                "org.freedesktop.ConsoleKit.Seat",
+                                                "ActivateSession")))
+    {
+      g_warning ("failed to create new message");
+      return FALSE;
+    }
+
+  if (!dbus_message_append_args (message,
+                                 DBUS_TYPE_OBJECT_PATH,
+                                 &ssid,
+                                 DBUS_TYPE_INVALID))
+    {
+      g_warning ("failed to append args");
+      return FALSE;
+    }
+
+  if (!(reply = dbus_connection_send_with_reply_and_block (dbus_g_connection_get_connection (priv->system_bus),
+                                                           message,
+                                                           -1,
+                                                           &error)))
+    {
+      if (dbus_error_is_set (&error))
+        {
+          g_warning ("Failed to send message: %s", error.message);
+          dbus_error_free (&error);
+
+          return FALSE;
+        }
+    }
+
+  if (message)
+    {
+      dbus_message_unref (message);
+    }
+
+  if (reply)
+    {
+      dbus_message_unref (reply);
+    }
+
+  return TRUE;
+}
+
+gboolean
+users_service_dbus_can_activate_session (UsersServiceDbus *self)
+{
+  UsersServiceDbusPrivate *priv = USERS_SERVICE_DBUS_GET_PRIVATE (self);
+  gboolean can_activate = FALSE;
+  GError *error = NULL;
+
+  if (!priv->seat_proxy)
+    {
+      create_seat_proxy (self);
+    }
+
+  if (!priv->seat || priv->seat[0] == '\0')
+    {
+      return FALSE;
+    }
+
+  if (!dbus_g_proxy_call (priv->seat_proxy,
+                          "CanActivateSessions",
+                          &error,
+                          G_TYPE_INVALID,
+                          G_TYPE_BOOLEAN, &can_activate,
+                          G_TYPE_INVALID))
+    {
+      g_warning ("Failed to determine if seat can activate sessions: %s", error->message);
+      g_error_free (error);
+
+      return FALSE;
+    }
+
+  return can_activate;
+}
diff --git a/src/users-service-dbus.h b/src/users-service-dbus.h
new file mode 100644
index 0000000..fc14beb
--- /dev/null
+++ b/src/users-service-dbus.h
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2009 Canonical Ltd.
+ *
+ * Authors:
+ *     Cody Russell <crussell@canonical.com>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __USERS_SERVICE_DBUS_H__
+#define __USERS_SERVICE_DBUS_H__
+
+#include <glib.h>
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define USERS_SERVICE_DBUS_TYPE         (users_service_dbus_get_type ())
+#define USERS_SERVICE_DBUS(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), USERS_SERVICE_DBUS_TYPE, UsersServiceDbus))
+#define USERS_SERVICE_DBUS_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), USERS_SERVICE_DBUS_TYPE, UsersServiceDbusClass))
+#define IS_USERS_SERVICE_DBUS(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), USERS_SERVICE_DBUS_TYPE))
+#define IS_USERS_SERVICE_DBUS_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), USERS_SERVICE_DBUS_TYPE))
+#define USERS_SERVICE_DBUS_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), USERS_SERVICE_DBUS_TYPE, UsersServiceDbusClass))
+
+typedef struct _UsersServiceDbus      UsersServiceDbus;
+typedef struct _UsersServiceDbusClass UsersServiceDbusClass;
+typedef struct _UserData              UserData;
+
+struct _UserData
+{
+  gint64   uid;
+  gchar   *user_name;
+  gchar   *real_name;
+  gchar   *shell;
+  gint     login_count;
+  gchar   *icon_url;
+
+  GList   *sessions;
+
+  UsersServiceDbus *service;
+};
+
+#define MINIMUM_USERS           1
+#define MAXIMUM_USERS           7
+
+struct _UsersServiceDbus {
+  GObject parent;
+};
+
+struct _UsersServiceDbusClass {
+  GObjectClass parent_class;
+
+  /* Signals */
+  void     (* users_loaded)       (UsersServiceDbus *self, gpointer user_data);
+
+  void     (* user_added)         (UsersServiceDbus *self, gint64 uid, gpointer user_data);
+  void     (* user_removed)       (UsersServiceDbus *self, gint64 uid, gpointer user_data);
+  void     (* user_updated)       (UsersServiceDbus *self, gint64 uid, gpointer user_data);
+};
+
+GType users_service_dbus_get_type  (void) G_GNUC_CONST;
+
+gint      users_service_dbus_get_user_count        (UsersServiceDbus *self);
+GList    *users_service_dbus_get_user_list         (UsersServiceDbus *self);
+gboolean  users_service_dbus_can_activate_session  (UsersServiceDbus *self);
+gboolean  users_service_dbus_activate_user_session (UsersServiceDbus *self,
+                                                    UserData         *user);
+
+G_END_DECLS
+
+#endif
diff --git a/src/users-service.c b/src/users-service.c
index 7ad1732..9ebf5f5 100644
--- a/src/users-service.c
+++ b/src/users-service.c
@@ -1,24 +1,25 @@
 /*
-A small wrapper utility to load indicators and put them as menu items
-into the gnome-panel using it's applet interface.
-
-Copyright 2009 Canonical Ltd.
-
-Authors:
-    Ted Gould <ted@canonical.com>
-
-This program is free software: you can redistribute it and/or modify it 
-under the terms of the GNU General Public License version 3, as published 
-by the Free Software Foundation.
-
-This program is distributed in the hope that it will be useful, but 
-WITHOUT ANY WARRANTY; without even the implied warranties of 
-MERCHANTABILITY, SATISFACTORY QUALITY, 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 this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
+ * A small wrapper utility to load indicators and put them as menu items
+ * into the gnome-panel using it's applet interface.
+ *
+ * Copyright 2009 Canonical Ltd.
+ *
+ * Authors:
+ *    Ted Gould <ted@canonical.com>
+ *    Cody Russell <crussell@canonical.com>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
 
 #include <config.h>
 
@@ -33,15 +34,27 @@ with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <libdbusmenu-glib/menuitem.h>
 
 #include "dbus-shared-names.h"
+#include "users-service-dbus.h"
 
 #define GUEST_SESSION_LAUNCHER  "/usr/share/gdm/guest-session/guest-session-launch"
 
-static DBusGConnection * session_bus = NULL;
-static DBusGConnection * system_bus = NULL;
-static DBusGProxy * bus_proxy = NULL;
-static DBusGProxy * gdm_proxy = NULL;
-static DbusmenuMenuitem * root_menuitem = NULL;
-static GMainLoop * mainloop = NULL;
+typedef struct _ActivateData ActivateData;
+struct _ActivateData
+{
+  UsersServiceDbus *service;
+  UserData *user;
+};
+
+static DBusGConnection   *session_bus = NULL;
+static DBusGConnection   *system_bus = NULL;
+static DBusGProxy        *bus_proxy = NULL;
+static DBusGProxy        *gdm_proxy = NULL;
+static DbusmenuMenuitem  *root_menuitem = NULL;
+static GMainLoop         *mainloop = NULL;
+static UsersServiceDbus  *dbus_interface = NULL;
+
+static gint   count;
+static GList *users;
 
 static gboolean
 check_guest_session (void)
@@ -137,29 +150,134 @@ lock_screen (DbusmenuMenuitem * mi, gpointer data)
 }
 
 static void
-create_items (DbusmenuMenuitem * root) {
-	DbusmenuMenuitem * mi = NULL;
-
-	mi = dbusmenu_menuitem_new();
-	dbusmenu_menuitem_property_set(mi, DBUSMENU_MENUITEM_PROP_LABEL, _("Lock Screen"));
-	g_signal_connect(G_OBJECT(mi), DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED, G_CALLBACK(lock_screen), NULL);
-	dbusmenu_menuitem_child_append(root, mi);
-
-	if (check_guest_session()) {
-		mi = dbusmenu_menuitem_new();
-		dbusmenu_menuitem_property_set(mi, DBUSMENU_MENUITEM_PROP_LABEL, _("Guest Session"));
-		dbusmenu_menuitem_child_append(root, mi);
-		g_signal_connect(G_OBJECT(mi), DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED, G_CALLBACK(activate_guest_session), NULL);
-	}
+activate_user_session (DbusmenuMenuitem *mi, gpointer user_data)
+{
+  UserData *user = (UserData *)user_data;
+  UsersServiceDbus *service = user->service;
 
-	if (check_new_session()) {
-		mi = dbusmenu_menuitem_new();
-		dbusmenu_menuitem_property_set(mi, DBUSMENU_MENUITEM_PROP_LABEL, _("Switch User..."));
-		dbusmenu_menuitem_child_append(root, mi);
-		g_signal_connect(G_OBJECT(mi), DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED, G_CALLBACK(activate_new_session), NULL);
-	}
+  users_service_dbus_activate_user_session (service, user);
+}
 
-	return;
+static void
+remove_menu_item (DbusmenuMenuitem *root, gpointer user_data)
+{
+  DbusmenuMenuitem *child = (DbusmenuMenuitem *)user_data;
+
+  dbusmenu_menuitem_child_delete (root, child);
+}
+
+static gint
+compare_users_by_username (const gchar *a,
+                           const gchar *b)
+{
+  UserData *user1 = (UserData *)a;
+  UserData *user2 = (UserData *)b;
+
+  return g_strcmp0 (user1->user_name, user2->user_name);
+}
+
+static void
+rebuild_items (DbusmenuMenuitem *root,
+               UsersServiceDbus *service)
+{
+  DbusmenuMenuitem *mi = NULL;
+  GList *u;
+  UserData *user;
+  gboolean can_activate;
+
+  can_activate = users_service_dbus_can_activate_session (service);
+
+  dbusmenu_menuitem_foreach (root, remove_menu_item, NULL);
+
+  mi = dbusmenu_menuitem_new();
+  dbusmenu_menuitem_property_set(mi, DBUSMENU_MENUITEM_PROP_LABEL, _("Lock Screen"));
+  g_signal_connect(G_OBJECT(mi), DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED, G_CALLBACK(lock_screen), NULL);
+  dbusmenu_menuitem_child_append(root, mi);
+
+  if (can_activate == TRUE)
+    {
+      if (check_guest_session ())
+        {
+          mi = dbusmenu_menuitem_new ();
+          dbusmenu_menuitem_property_set (mi, DBUSMENU_MENUITEM_PROP_LABEL, _("Guest Session"));
+          dbusmenu_menuitem_child_append (root, mi);
+          g_signal_connect (G_OBJECT (mi), DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED, G_CALLBACK (activate_guest_session), NULL);
+        }
+
+      if (count > MINIMUM_USERS && count < MAXIMUM_USERS)
+        {
+          if (users != NULL)
+            {
+              GList *l = NULL;
+
+              for (l = users; l != NULL; l = l->next)
+                {
+                  users = g_list_delete_link (users, l);
+                }
+
+              users = NULL;
+            }
+
+          users = users_service_dbus_get_user_list (service);
+
+          users = g_list_sort (users, (GCompareFunc)compare_users_by_username);
+
+          for (u = users; u != NULL; u = g_list_next (u))
+            {
+              user = u->data;
+
+              user->service = service;
+
+              mi = dbusmenu_menuitem_new ();
+              dbusmenu_menuitem_property_set (mi, DBUSMENU_MENUITEM_PROP_LABEL, user->real_name);
+              dbusmenu_menuitem_child_append (root, mi);
+              g_signal_connect (G_OBJECT (mi), DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED, G_CALLBACK (activate_user_session), user);
+            }
+        }
+
+      if (check_new_session ())
+        {
+          mi = dbusmenu_menuitem_new ();
+          dbusmenu_menuitem_property_set (mi, DBUSMENU_MENUITEM_PROP_LABEL, _("New Session..."));
+          dbusmenu_menuitem_child_append (root, mi);
+          g_signal_connect (G_OBJECT (mi), DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED, G_CALLBACK (activate_new_session), NULL);
+        }
+    }
+}
+
+static void
+user_added (UsersServiceDbus *service,
+            UserData         *user,
+            gpointer          user_data)
+{
+  DbusmenuMenuitem *root = (DbusmenuMenuitem *)user_data;
+
+  count++;
+
+  rebuild_items (root, service);
+}
+
+static void
+user_removed (UsersServiceDbus *service,
+              UserData         *user,
+              gpointer          user_data)
+{
+  DbusmenuMenuitem *root = (DbusmenuMenuitem *)user_data;
+
+  count--;
+
+  rebuild_items (root, service);
+}
+
+static void
+create_items (DbusmenuMenuitem *root,
+              UsersServiceDbus *service)
+{
+  g_return_if_fail (IS_USERS_SERVICE_DBUS (service));
+
+  count = users_service_dbus_get_user_count (service);
+
+  rebuild_items (root, service);
 }
 
 int
@@ -167,35 +285,46 @@ main (int argc, char ** argv)
 {
     g_type_init();
 
-	/* Setting up i18n and gettext.  Apparently, we need
-	   all of these. */
-	setlocale (LC_ALL, "");
-	bindtextdomain (GETTEXT_PACKAGE, GNOMELOCALEDIR);
-	textdomain (GETTEXT_PACKAGE);
+    /* Setting up i18n and gettext.  Apparently, we need
+       all of these. */
+    setlocale (LC_ALL, "");
+    bindtextdomain (GETTEXT_PACKAGE, GNOMELOCALEDIR);
+    textdomain (GETTEXT_PACKAGE);
 
     session_bus = dbus_g_bus_get(DBUS_BUS_SESSION, NULL);
-    bus_proxy = dbus_g_proxy_new_for_name(session_bus, DBUS_SERVICE_DBUS, DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS);
+    bus_proxy = dbus_g_proxy_new_for_name (session_bus, DBUS_SERVICE_DBUS, DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS);
     GError * error = NULL;
     guint nameret = 0;
 
     if (!org_freedesktop_DBus_request_name(bus_proxy, INDICATOR_USERS_DBUS_NAME, 0, &nameret, &error)) {
         g_error("Unable to call to request name");
         return 1;
-    }   
+    }
 
     if (nameret != DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER) {
         g_error("Unable to get name");
         return 1;
-    }   
+    }
 
-    root_menuitem = dbusmenu_menuitem_new();
-	g_debug("Root ID: %d", dbusmenu_menuitem_get_id(root_menuitem));
+    dbus_interface = g_object_new (USERS_SERVICE_DBUS_TYPE, NULL);
 
-	create_items(root_menuitem);
+    root_menuitem = dbusmenu_menuitem_new ();
+    g_debug ("Root ID: %d", dbusmenu_menuitem_get_id (root_menuitem));
+
+    create_items (root_menuitem, dbus_interface);
 
     DbusmenuServer * server = dbusmenu_server_new(INDICATOR_USERS_DBUS_OBJECT);
     dbusmenu_server_set_root(server, root_menuitem);
 
+    g_signal_connect (G_OBJECT (dbus_interface),
+                      "user-added",
+                      G_CALLBACK (user_added),
+                      root_menuitem);
+    g_signal_connect (G_OBJECT (dbus_interface),
+                      "user-removed",
+                      G_CALLBACK (user_removed),
+                      root_menuitem);
+
     mainloop = g_main_loop_new(NULL, FALSE);
     g_main_loop_run(mainloop);
 
diff --git a/src/users-service.list b/src/users-service.list
new file mode 100644
index 0000000..36f34ba
--- /dev/null
+++ b/src/users-service.list
@@ -0,0 +1 @@
+VOID:INT64
diff --git a/src/users-service.xml b/src/users-service.xml
new file mode 100644
index 0000000..c90f1e8
--- /dev/null
+++ b/src/users-service.xml
@@ -0,0 +1,56 @@
+<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN" "http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
+<node name="/org/gnome/DisplayManager/UserManager">
+  <interface name="org.gnome.DisplayManager.UserManager">
+
+    <!-- Get the number of known users -->
+    <method name="CountUsers">
+      <arg name="user_count" direction="out" type="i"/>
+    </method>
+
+    <!-- Get the list of known UIDs -->
+    <method name="GetUserList">
+      <arg name="uids" direction="out" type="ax"/>
+    </method>
+
+    <!-- Get user info for a user -->
+    <method name="GetUserInfo">
+      <arg name="uid" direction="in" type="x"/>
+      <arg name="user_name" direction="out" type="s"/>
+      <arg name="real_name" direction="out" type="s"/>
+      <arg name="shell" direction="out" type="s"/>
+      <arg name="login_count" direction="out" type="i"/>
+      <arg name="icon_url" direction="out" type="s"/>
+    </method>
+
+    <!-- Get user info for a list of users -->
+    <method name="GetUsersInfo">
+      <arg name="uid" direction="in" type="ax"/>
+      <!-- (uid, user_name, real_name, shell, icon_url) -->
+      <arg name="user_info" direction="out" type="a(xsssis)"/>
+    </method>
+
+    <!-- Query if the initial user list is loaded -->
+    <method name="GetUsersLoaded">
+      <arg name="is_loaded" direction="out" type="b"/>
+    </method>
+
+    <!-- Triggered when the initial user list is loaded -->
+    <signal name="UsersLoaded"></signal>
+
+    <!-- Triggered when a users are added to/removed from the system.
+         Clients should monitor these signals as soon as they connect to
+         this object -->
+    <signal name="UserAdded">
+      <arg name="uid" type="x"/>
+    </signal>
+    <signal name="UserRemoved">
+      <arg name="uid" type="x"/>
+    </signal>
+
+    <!-- Triggered when a user has updated information -->
+    <signal name="UserUpdated">
+      <arg name="uid" type="x"/>
+    </signal>
+
+  </interface>
+</node>