Disable user switching if logind says it isn't supported

This should work now that seat_local_get_active_session returns the
proper value for non-seat0 seats.

Note: systemd-logind v245 and older erroneously report
CanMultiSession=no on non-seat0 seats even when it is supported.  This
change will break those users.  See
<https://github.com/systemd/systemd/pull/15337>.

5 files changed, 97 insertions, 6 deletions

diff --git a/src/lightdm.c b/src/lightdm.c
index 0ccfcd78..7fd77ed9 100644
--- a/src/lightdm.c
+++ b/src/lightdm.c
@@ -423,12 +423,10 @@ add_login1_seat (Login1Seat *login1_seat)
     {
         set_seat_properties (seat, seat_name);
 
-        if (!login1_seat_get_can_multi_session (login1_seat))
-        {
+        gboolean can_multi_session = login1_seat_get_can_multi_session (login1_seat);
+        if (!can_multi_session)
             g_debug ("Seat %s has property CanMultiSession=no", seat_name);
-            /* XXX: uncomment this line after bug #1371250 is closed.
-            seat_set_property (seat, "allow-user-switching", "false"); */
-        }
+        seat_set_supports_multi_session (seat, can_multi_session);
 
         if (is_seat0)
             seat_set_property (seat, "exit-on-failure", "true");
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 734f6482..98a3acce 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -241,6 +241,7 @@ TESTS = \
 	test-multi-seat-autologin-seat1 \
 	test-multi-seat-seat0-non-graphical \
 	test-multi-seat-seat0-non-graphical-disabled \
+	test-multi-seat-no-multi-session \
 	test-multi-seat-non-graphical \
 	test-multi-seat-non-graphical-disabled \
 	test-multi-seat-change-graphical \
@@ -476,6 +477,7 @@ EXTRA_DIST = \
 	scripts/multi-seat-change-graphical.conf \
 	scripts/multi-seat-change-graphical-disabled.conf \
 	scripts/multi-seat-login.conf \
+	scripts/multi-seat-no-multi-session \
 	scripts/multi-seat-non-graphical.conf \
 	scripts/multi-seat-non-graphical-disabled.conf \
 	scripts/multi-seat-seat0-non-graphical.conf \
diff --git a/tests/scripts/multi-seat-no-multi-session.conf b/tests/scripts/multi-seat-no-multi-session.conf
new file mode 100644
index 00000000..672b0e4a
--- /dev/null
+++ b/tests/scripts/multi-seat-no-multi-session.conf
@@ -0,0 +1,86 @@
+#
+# Check that logging out from a CanMultiSession=false seat activates greeter on
+# that seat.
+#
+
+[Seat:*]
+user-session=default
+
+#?*START-DAEMON
+#?RUNNER DAEMON-START
+
+# seat0 starts
+#?XSERVER-0 START VT=7 SEAT=seat0
+#?*XSERVER-0 INDICATE-READY
+#?XSERVER-0 INDICATE-READY
+#?XSERVER-0 ACCEPT-CONNECT
+#?GREETER-X-0 START XDG_SEAT=seat0 XDG_VTNR=7 XDG_SESSION_CLASS=greeter
+#?LOGIN1 ACTIVATE-SESSION SESSION=c0
+#?XSERVER-0 ACCEPT-CONNECT
+#?GREETER-X-0 CONNECT-XSERVER
+#?GREETER-X-0 CONNECT-TO-DAEMON
+#?GREETER-X-0 CONNECTED-TO-DAEMON
+
+# Add seat1
+#?*ADD-SEAT ID=seat1 CAN-MULTI-SESSION=FALSE
+#?XSERVER-1 START SEAT=seat1
+#?*SEAT-CAN-SWITCH PATH=/org/freedesktop/DisplayManager/Seat1
+#?RUNNER SEAT-CAN-SWITCH PATH=/org/freedesktop/DisplayManager/Seat1 CAN-SWITCH=FALSE
+#?*XSERVER-1 INDICATE-READY
+#?XSERVER-1 INDICATE-READY
+#?XSERVER-1 ACCEPT-CONNECT
+#?GREETER-X-1 START XDG_SEAT=seat1 XDG_SESSION_CLASS=greeter
+#?LOGIN1 ACTIVATE-SESSION SESSION=c1
+#?XSERVER-1 ACCEPT-CONNECT
+#?GREETER-X-1 CONNECT-XSERVER
+#?GREETER-X-1 CONNECT-TO-DAEMON
+#?GREETER-X-1 CONNECTED-TO-DAEMON
+
+# Log in seat0 so that its active session is not a greeter (in case there is a
+# cross-seat bug).
+#?*GREETER-X-0 AUTHENTICATE USERNAME=no-password1
+#?GREETER-X-0 AUTHENTICATION-COMPLETE USERNAME=no-password1 AUTHENTICATED=TRUE
+#?*GREETER-X-0 START-SESSION
+#?GREETER-X-0 TERMINATE SIGNAL=15
+#?SESSION-X-0 START XDG_SEAT=seat0 XDG_VTNR=7 XDG_GREETER_DATA_DIR=.*/no-password1 XDG_SESSION_TYPE=x11 XDG_SESSION_DESKTOP=default USER=no-password1
+#?LOGIN1 ACTIVATE-SESSION SESSION=c2
+#?XSERVER-0 ACCEPT-CONNECT
+#?SESSION-X-0 CONNECT-XSERVER
+
+# Log in seat1
+#?*GREETER-X-1 AUTHENTICATE USERNAME=no-password2
+#?GREETER-X-1 AUTHENTICATION-COMPLETE USERNAME=no-password2 AUTHENTICATED=TRUE
+#?*GREETER-X-1 START-SESSION
+#?GREETER-X-1 TERMINATE SIGNAL=15
+#?SESSION-X-1 START XDG_SEAT=seat1 XDG_GREETER_DATA_DIR=.*/no-password2 XDG_SESSION_TYPE=x11 XDG_SESSION_DESKTOP=default USER=no-password2
+#?LOGIN1 ACTIVATE-SESSION SESSION=c3
+#?XSERVER-1 ACCEPT-CONNECT
+#?SESSION-X-1 CONNECT-XSERVER
+
+# Logout seat1
+#?*SESSION-X-1 LOGOUT
+#?XSERVER-1 TERMINATE SIGNAL=15
+
+# Ensure that the X server and greeter for seat1 are not restarted until after
+# the user logs out.  WAIT is not needed here because XSERVER-1 cannot terminate
+# and start concurrently.
+#?*FENCE
+
+#?XSERVER-1 START SEAT=seat1
+#?*XSERVER-1 INDICATE-READY
+#?XSERVER-1 INDICATE-READY
+#?XSERVER-1 ACCEPT-CONNECT
+#?GREETER-X-1 START XDG_SEAT=seat1 XDG_SESSION_CLASS=greeter
+#?LOGIN1 ACTIVATE-SESSION SESSION=c4
+#?XSERVER-1 ACCEPT-CONNECT
+#?GREETER-X-1 CONNECT-XSERVER
+#?GREETER-X-1 CONNECT-TO-DAEMON
+#?GREETER-X-1 CONNECTED-TO-DAEMON
+
+# Cleanup
+#?*STOP-DAEMON
+#?SESSION-X-0 TERMINATE SIGNAL=15
+#?XSERVER-0 TERMINATE SIGNAL=15
+#?GREETER-X-1 TERMINATE SIGNAL=15
+#?XSERVER-1 TERMINATE SIGNAL=15
+#?RUNNER DAEMON-EXIT STATUS=0
diff --git a/tests/src/test-runner.c b/tests/src/test-runner.c
index 118c786f..7de9694c 100644
--- a/tests/src/test-runner.c
+++ b/tests/src/test-runner.c
@@ -697,10 +697,11 @@ handle_command (const gchar *command)
     }
     else if (strcmp (name, "SEAT-CAN-SWITCH") == 0)
     {
+        const gchar *path = g_hash_table_lookup (params, "PATH");
         g_autoptr(GError) error = NULL;
         g_autoptr(GVariant) result = g_dbus_connection_call_sync (dbus_conn,
                                                                   "org.freedesktop.DisplayManager",
-                                                                  "/org/freedesktop/DisplayManager/Seat0",
+                                                                  path ? path : "/org/freedesktop/DisplayManager/Seat0",
                                                                   "org.freedesktop.DBus.Properties",
                                                                   "Get",
                                                                   g_variant_new ("(ss)", "org.freedesktop.DisplayManager.Seat", "CanSwitch"),
@@ -711,6 +712,8 @@ handle_command (const gchar *command)
                                                                   &error);
 
         g_autoptr(GString) status = g_string_new ("RUNNER SEAT-CAN-SWITCH");
+        if (path)
+            g_string_append_printf (status, " PATH=%s", path);
         if (result)
         {
             g_autoptr(GVariant) value = NULL;
diff --git a/tests/test-multi-seat-no-multi-session b/tests/test-multi-seat-no-multi-session
new file mode 100755
index 00000000..6ddd1034
--- /dev/null
+++ b/tests/test-multi-seat-no-multi-session
@@ -0,0 +1,2 @@
+#!/bin/sh
+./src/dbus-env ./src/test-runner multi-seat-no-multi-session test-gobject-greeter