daemon: Support X servers built with -Dlisten_tcp=true

Xorg since version 1.17 doesn't listen to tcp sockets by default
unless it's explicitly built with -Dlisten_tcp=true.

GDM currently assumes X servers 1.17 and later are always built
without specifying -Dlisten_tcp=true and doesn't work properly
otherwise.

This commit enhances GDM to better handle these non-standard builds by
always passing '-nolisten tcp' on the command line when tcp should
be disabled, and likewise always passing '-listen tcp' on the command
line, assuming the X server is new enough to support it, when tcp
should be enabled.

Related #704

1 files changed, 11 insertions, 10 deletions

diff --git a/daemon/gdm-server.c b/daemon/gdm-server.c
index 1ba00d45..e5d23521 100644
--- a/daemon/gdm-server.c
+++ b/daemon/gdm-server.c
@@ -317,18 +317,19 @@ gdm_server_resolve_command_line (GdmServer  *server,
          * by default anymore. In older versions we need to pass
          * -nolisten tcp to disable listening on tcp sockets.
          */
-#ifdef HAVE_XSERVER_THAT_DEFAULTS_TO_LOCAL_ONLY
-        if (!server->disable_tcp && ! query_in_arglist) {
-                argv[len++] = g_strdup ("-listen");
-                argv[len++] = g_strdup ("tcp");
-        }
-#else
-        if (server->disable_tcp && ! query_in_arglist) {
-                argv[len++] = g_strdup ("-nolisten");
-                argv[len++] = g_strdup ("tcp");
-        }
+        if (!query_in_arglist) {
+                if (server->disable_tcp) {
+                        argv[len++] = g_strdup ("-nolisten");
+                        argv[len++] = g_strdup ("tcp");
+                }
 
+#ifdef HAVE_XSERVER_WITH_LISTEN
+                if (!server->disable_tcp) {
+                        argv[len++] = g_strdup ("-listen");
+                        argv[len++] = g_strdup ("tcp");
+                }
 #endif
+        }
 
         if (vtarg != NULL && ! gotvtarg) {
                 argv[len++] = g_strdup (vtarg);