Merge branch 'lsan-dynamic-loading' into 'main'

glib-private: Check for LSAN support at runtime when controlling it

See merge request GNOME/glib!3672

glib/glib-private.h

@@ -37,14 +37,51 @@
 /*
  * %_GLIB_ADDRESS_SANITIZER:
  *
- * Private macro defined if the AddressSanitizer is in use.
+ * Private macro defined if the AddressSanitizer is in use by GLib itself.
  */
 #define _GLIB_ADDRESS_SANITIZER
 
 #include <sanitizer/lsan_interface.h>
 
+/* If GLib itself is not compiled with ASAN sanitizer we may still want to
+ * control it in case it's linked by the loading application, so we need to
+ * do this check dynamically.
+ * However MinGW doesn't support weak attribute properly (even if it advertises
+ * it), so we ignore it in such case since it's not convenient to go through
+ * dlsym().
+ * Under MSVC we could use alternatename, but it doesn't seem to be as reliable
+ * as we'd like: https://stackoverflow.com/a/11529277/210151 and
+ * https://devblogs.microsoft.com/oldnewthing/20200731-00/?p=104024
+ */
+#elif defined (G_OS_UNIX) && g_macro__has_attribute (weak)
+
+#define HAS_DYNAMIC_ASAN_LOADING
+
+void __lsan_enable (void) __attribute__ ((weak));
+void __lsan_disable (void) __attribute__ ((weak));
+void __lsan_ignore_object (const void *p) __attribute__ ((weak));
+
 #endif
 
+/*
+ * g_leak_sanitizer_is_supported:
+ *
+ * Checks at runtime if LeakSanitizer is currently supported by the running
+ * binary. This may imply that GLib itself is not compiled with sanitizer
+ * but that the loading program is.
+ */
+static inline gboolean
+g_leak_sanitizer_is_supported (void)
+{
+#if defined (_GLIB_ADDRESS_SANITIZER)
+  return TRUE;
+#elif defined (HAS_DYNAMIC_ASAN_LOADING)
+  return __lsan_enable != NULL && __lsan_ignore_object != NULL;
+#else
+  return FALSE;
+#endif
+}
+
 /*
  * g_ignore_leak:
  * @p: any pointer
@@ -57,9 +94,12 @@
 static inline void
 g_ignore_leak (gconstpointer p)
 {
-#ifdef _GLIB_ADDRESS_SANITIZER
+#if defined (_GLIB_ADDRESS_SANITIZER)
   if (p != NULL)
     __lsan_ignore_object (p);
+#elif defined (HAS_DYNAMIC_ASAN_LOADING)
+  if (p != NULL && __lsan_ignore_object != NULL)
+    __lsan_ignore_object (p);
 #endif
 }
 
@@ -73,9 +113,11 @@ g_ignore_leak (gconstpointer p)
 static inline void
 g_ignore_strv_leak (GStrv strv)
 {
-#ifdef _GLIB_ADDRESS_SANITIZER
   gchar **item;
 
+  if (!g_leak_sanitizer_is_supported ())
+    return;
+
   if (strv)
     {
       g_ignore_leak (strv);
@@ -83,7 +125,6 @@ g_ignore_strv_leak (GStrv strv)
       for (item = strv; *item != NULL; item++)
         g_ignore_leak (*item);
     }
-#endif
 }
 
 /*
@@ -98,8 +139,11 @@ g_ignore_strv_leak (GStrv strv)
 static inline void
 g_begin_ignore_leaks (void)
 {
-#ifdef _GLIB_ADDRESS_SANITIZER
+#if defined (_GLIB_ADDRESS_SANITIZER)
   __lsan_disable ();
+#elif defined (HAS_DYNAMIC_ASAN_LOADING)
+  if (__lsan_disable != NULL)
+    __lsan_disable ();
 #endif
 }
 
@@ -112,11 +156,16 @@ g_begin_ignore_leaks (void)
 static inline void
 g_end_ignore_leaks (void)
 {
-#ifdef _GLIB_ADDRESS_SANITIZER
+#if defined (_GLIB_ADDRESS_SANITIZER)
   __lsan_enable ();
+#elif defined (HAS_DYNAMIC_ASAN_LOADING)
+  if (__lsan_enable != NULL)
+    __lsan_enable ();
 #endif
 }
 
+#undef HAS_DYNAMIC_ASAN_LOADING
+
 GMainContext *          g_get_worker_context            (void);
 gboolean                g_check_setuid                  (void);
 GMainContext *          g_main_context_new_with_next_id (guint next_id);

glib/gmacros.h

@@ -185,6 +185,7 @@
 #define g_macro__has_attribute___pure__ G_GNUC_CHECK_VERSION (2, 96)
 #define g_macro__has_attribute___sentinel__ G_GNUC_CHECK_VERSION (4, 0)
 #define g_macro__has_attribute___unused__ G_GNUC_CHECK_VERSION (2, 4)
+#define g_macro__has_attribute___weak__ G_GNUC_CHECK_VERSION (2, 8)
 #define g_macro__has_attribute_cleanup G_GNUC_CHECK_VERSION (3, 3)
 #define g_macro__has_attribute_fallthrough G_GNUC_CHECK_VERSION (6, 0)
 #define g_macro__has_attribute_may_alias G_GNUC_CHECK_VERSION (3, 3)