plugin-loader: Optionally use RTLD_NOW with dlopen()

This can be useful when writing custom plugins as typos or missing
linker flags that result in unresolved symbols in the shared object
could otherwise cause late crashes.  In particular, if such a symbol
is used in a code path that is rarely executed.  During development
and testing using RTLD_NOW instead of RTLD_LAZY will prevent the
plugin from getting loaded and makes the error visible immediately.

1 files changed, 11 insertions, 6 deletions

diff --git a/src/libstrongswan/plugins/plugin_loader.c b/src/libstrongswan/plugins/plugin_loader.c
index f7ac347d2..01d0495be 100644
--- a/src/libstrongswan/plugins/plugin_loader.c
+++ b/src/libstrongswan/plugins/plugin_loader.c
@@ -356,6 +356,7 @@ static plugin_entry_t *load_plugin(private_plugin_loader_t *this, char *name,
 {
 	plugin_entry_t *entry;
 	void *handle;
+	int flag = RTLD_LAZY;
 
 	switch (create_plugin(this, RTLD_DEFAULT, name, FALSE, critical, &entry))
 	{
@@ -380,15 +381,19 @@ static plugin_entry_t *load_plugin(private_plugin_loader_t *this, char *name,
 			return NULL;
 		}
 	}
-	handle = dlopen(file, RTLD_LAZY
+	if (lib->settings->get_bool(lib->settings, "%s.dlopen_use_rtld_now",
+								lib->ns, FALSE))
+	{
+		flag = RTLD_NOW;
+	}
 #ifdef RTLD_NODELETE
-	/* if supported, do not unload library when unloading a plugin. It really
-	 * doesn't matter in productive systems, but causes many (dependency)
-	 * library reloads during unit tests. Some libraries can't handle that,
+	/* If supported, do not unload the library when unloading a plugin. It
+	 * really doesn't matter in productive systems, but causes many (dependency)
+	 * library reloads during unit tests. Some libraries can't handle that, e.g.
 	 * GnuTLS leaks file descriptors in its library load/unload functions. */
-					| RTLD_NODELETE
+	flag |= RTLD_NODELETE;
 #endif
-					);
+	handle = dlopen(file, flag);
 	if (handle == NULL)
 	{
 		DBG1(DBG_LIB, "plugin '%s' failed to load: %s", name, dlerror());