Fix issue where loaded global modules aren't freed

Globally loaded modules would previously call LoadLibrary on Windows, but never FreeLibrary. This would result in said library keeping an internal reference counter of 1 until the application exited its entry-point, resulting in possible shutdown issues.

This commit makes sure that we correctly free modules (and unload them in the platform-specific APIs) whenever Mono itself is shutting down, ensuring the expected result of Mono-loaded libraries being correctly freed.

diff --git a/mono/metadata/loader.c b/mono/metadata/loader.c
index 85b5639384b1e70c1ac590fc5dd5d3108ea336d0..b41742ab7372d825a37a3cde7dd83d3b2cbfc2a0 100644 (file)
--- a/mono/metadata/loader.c
+++ b/mono/metadata/loader.c
@@ -74,6 +74,7 @@ static gint32 signatures_size;
 MonoNativeTlsKey loader_lock_nest_id;
 
 static void dllmap_cleanup (void);
+static void cached_module_cleanup(void);
 
 static void
 global_loader_data_lock (void)
@@ -117,6 +118,7 @@ void
 mono_loader_cleanup (void)
 {
        dllmap_cleanup ();
+       cached_module_cleanup ();
 
        mono_native_tls_free (loader_lock_nest_id);
 
@@ -1137,6 +1139,21 @@ mono_loader_register_module (const char *name, MonoDl *module)
        g_hash_table_insert (global_module_map, g_strdup (name), module);
 }
 
+static void
+remove_cached_module(gpointer key, gpointer value, gpointer user_data)
+{
+       mono_dl_close((MonoDl*)value);
+}
+
+static void
+cached_module_cleanup(void)
+{
+       g_hash_table_foreach(global_module_map, remove_cached_module, NULL);
+
+       g_hash_table_destroy(global_module_map);
+       global_module_map = NULL;
+}
+
 static MonoDl *internal_module;
 
 static gboolean