Submitted By:            Bruce Dubbs <bdubbs at linuxfromscratch dot org>
Date:                    2026-09-18
Initial Package Version: 51.0
Upstream Status:         Not yet submitted
Origin:                  Self with the help of claude
Description:             Fixes the application hanging on start due to
                         a missing selinux library (which has never been in BLFS).

Fix load_selinux() to always call g_once_init_leave_pointer()

load_selinux() in src/selinux/gsm-selinux.c calls
g_once_init_enter_pointer(&module) and then, on failure to open
libselinux.so.1 or resolve any of the required symbols, returns
FALSE directly from inside the guarded block without ever calling
g_once_init_leave_pointer().

g_once_init_enter_pointer()/g_once_init_leave_pointer() are a
strict pair: once enter_pointer() returns TRUE for a thread, that
thread MUST call leave_pointer() on every exit path. Skipping it
leaves the static guard permanently stuck in its "initialization
in progress" state, so every future call to load_selinux() from
any thread (including the main thread building the process table)
blocks forever in g_once_init_enter_pointer()'s wait loop. This
means gnome-system-monitor hangs indefinitely on startup, with no
window ever presented, on any system where libselinux.so.1 is not
installed (e.g. a system with no SELinux support built, such as a
default LFS/BLFS build).

The fix collects the g_module_open()/g_module_symbol() failure
handling into a single block that always finishes with exactly one
g_once_init_leave_pointer(&module, selinux) call, with selinux left
NULL on any failure so subsequent calls short-circuit instantly via
"return module != NULL;" instead of hanging or retrying.

diff -Naur src/selinux.orig/gsm-selinux.c src/selinux/gsm-selinux.c
--- a/src/selinux.orig/gsm-selinux.c	2026-09-11 10:59:37.000000000 -0500
+++ b/src/selinux/gsm-selinux.c	2026-09-18 18:15:11.540709606 -0500
@@ -17,40 +17,38 @@
 static gboolean
 load_selinux (void)
 {
+  static gsize initialized = 0;   // FALSE
   static GModule *module = NULL;
 
-  if (g_once_init_enter_pointer (&module)) {
+  if (g_once_init_enter (&initialized)) {
     GModule *selinux = g_module_open ("libselinux.so.1",
-                                      G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL);
-
-    if (!g_module_symbol (selinux, "getpidcon", (gpointer *) &getpidcon)) {
-      g_debug ("Could not load getpidcon from libselinux.so.0");
-      return FALSE;
-    } else {
-      g_debug ("Loaded getpidcon from libselinux.so.0");
-    }
-
-    if (!g_module_symbol (selinux, "freecon", (gpointer *) &freecon)) {
-      g_debug ("Could not load freecon from libselinux.so.0");
-      return FALSE;
-    } else {
-      g_debug ("Loaded freecon from libselinux.so.0");
+                                       G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL);
+    if (selinux != NULL) {
+      if (!g_module_symbol (selinux, "getpidcon", (gpointer *) &getpidcon)) {
+        g_debug ("Could not load getpidcon from libselinux.so.1");
+        g_module_close (selinux);
+        selinux = NULL;
+      } else if (!g_module_symbol (selinux, "freecon", (gpointer *) &freecon)) {
+        g_debug ("Could not load freecon from libselinux.so.1");
+        g_module_close (selinux);
+        selinux = NULL;
+      } else if (!g_module_symbol (selinux,
+                                    "is_selinux_enabled",
+                                    (gpointer *) &is_selinux_enabled)) {
+        g_debug ("Could not load is_selinux_enabled from libselinux.so.1");
+        g_module_close (selinux);
+        selinux = NULL;
+      } else {
+        g_debug ("Loaded getpidcon, freecon, is_selinux_enabled from libselinux.so.1");
+        g_module_make_resident (selinux);
+      }
     }
 
-    if (!g_module_symbol (selinux,
-                          "is_selinux_enabled",
-                          (gpointer *) &is_selinux_enabled)) {
-      g_debug ("Could not load is_selinux_enabled from libselinux.so.0");
-      return FALSE;
-    } else {
-      g_debug ("Loaded is_selinux_enabled from libselinux.so.0");
-    }
-
-    g_module_make_resident (selinux);
-
-    g_once_init_leave_pointer (&module, g_steal_pointer (&selinux));
+    module = selinux;
+    g_once_init_leave (&initialized, 1); // Set initialized FALSE
   }
 
+
   return module != NULL;
 }