Fix crash if switching to greeter and it isn't installed

Author: robert-ancell

src/seat.c

@@ -392,7 +392,11 @@ display_server_stopped_cb (DisplayServer *display_server, Seat *seat)
         if (!active_session || session_get_display_server (active_session) == display_server)
         {
             l_debug (seat, "Active display server stopped, starting greeter");
-            seat_switch_to_greeter (seat);
+            if (!seat_switch_to_greeter (seat))
+            {
+                l_debug (seat, "Stopping; failed to start a greeter");
+                seat_stop (seat);
+            }
         }
     }
 
@@ -671,7 +675,11 @@ session_stopped_cb (Session *session, Seat *seat)
     else if (!IS_GREETER (session) && session == seat_get_active_session (seat))
     {
         l_debug (seat, "Active session stopped, starting greeter");
-        seat_switch_to_greeter (seat);
+        if (!seat_switch_to_greeter (seat))
+        {
+            l_debug (seat, "Stopping; failed to start a greeter");
+            seat_stop (seat);
+        }
     }
 
     /* Stop the display server if no-longer required */
@@ -1241,6 +1249,9 @@ seat_switch_to_greeter (Seat *seat)
     }
 
     greeter_session = create_greeter_session (seat);
+    if (!greeter_session)
+        return FALSE;
+
     if (seat->priv->session_to_activate)
         g_object_unref (seat->priv->session_to_activate);
     seat->priv->session_to_activate = g_object_ref (greeter_session);

tests/Makefile.am

@@ -22,6 +22,7 @@ TESTS = \
 	test-autologin-guest-in-background \
 	test-autologin-timeout-in-background \
 	test-autologin-invalid-user \
+	test-autologin-invalid-greeter \
 	test-autologin-invalid-session \
 	test-crash-authenticate \
 	test-autologin-xserver-crash \
@@ -72,6 +73,7 @@ TESTS = \
 	test-language \
 	test-language-no-accounts-service \
 	test-login-crash-authenticate \
+	test-login-invalid-greeter \
 	test-login-gobject \
 	test-login-gobject-manual \
 	test-login-gobject-manual-previous-session \
@@ -307,6 +309,7 @@ EXTRA_DIST = \
 	scripts/autologin-guest-logout.conf \
 	scripts/autologin-guest-timeout.conf \
 	scripts/autologin-in-background.conf \
+	scripts/autologin-invalid-greeter.conf \
 	scripts/autologin-guest-in-background.conf \
 	scripts/autologin-timeout-in-background.conf \
 	scripts/autologin-invalid-session.conf \
@@ -362,6 +365,7 @@ EXTRA_DIST = \
 	scripts/login-guest-logout.conf \
 	scripts/login-guest-no-setup-script.conf \
 	scripts/login-info-prompt.conf \
+	scripts/login-invalid-greeter.conf \
 	scripts/login-invalid-session.conf \
 	scripts/login-invalid-user.conf \
 	scripts/login-logout.conf \

tests/scripts/autologin-invalid-greeter.conf

@@ -0,0 +1,30 @@
+#
+# Check quits if autologin session ends and no valid greeter
+#
+
+[SeatDefaults]
+autologin-user=have-password1
+user-session=default
+
+#?RUNNER DAEMON-START
+
+# X server starts
+#?XSERVER-0 START VT=7
+
+# Daemon connects when X server is ready
+#?*XSERVER-0 INDICATE-READY
+#?XSERVER-0 INDICATE-READY
+#?XSERVER-0 ACCEPT-CONNECT
+
+# Session starts
+#?SESSION-X-0 START XDG_SEAT=seat0 XDG_VTNR=7 DESKTOP_SESSION=default USER=have-password1
+#?XSERVER-0 ACCEPT-CONNECT
+#?SESSION-X-0 CONNECT-XSERVER
+
+# Logout session
+#?*SESSION-X-0 LOGOUT
+
+# X server stops
+#?XSERVER-0 TERMINATE SIGNAL=15
+
+#?RUNNER DAEMON-EXIT STATUS=1

tests/scripts/login-invalid-greeter.conf

@@ -0,0 +1,7 @@
+#
+# Check fails to start if invalid greeter
+#
+
+#?RUNNER DAEMON-START
+
+#?RUNNER DAEMON-EXIT STATUS=1

tests/test-autologin-invalid-greeter

@@ -0,0 +1,2 @@
+#!/bin/sh
+./src/dbus-env ./src/test-runner autologin-invalid-greeter INVALID

tests/test-login-invalid-greeter

@@ -0,0 +1,2 @@
+#!/bin/sh
+./src/dbus-env ./src/test-runner login-invalid-greeter INVALID