ldso: shared-object lock and ctor test

This has to be used during shared object creation and destruction because global
lists are manipulated. We cannot use the 'Elf_object::lock' here because there
may be jump-slot relocations during object initialization.

Fixes #1350

repos/base/src/lib/ldso/main.cc

@@ -1100,6 +1100,17 @@ static Root_object *to_root(void *h)
 }
 
 
+/**
+ * Needed during shared object creation and destruction, since global lists are
+ * manipulated
+ */
+static Genode::Lock & shared_object_lock()
+{
+	static Genode::Lock _lock;
+	return _lock;
+}
+
+
 Genode::Shared_object::Shared_object(char const *file, unsigned flags)
 {
 	using namespace Linker;
@@ -1108,7 +1119,7 @@ Genode::Shared_object::Shared_object(char const *file, unsigned flags)
 		PDBG("open '%s'", file ? file : "binary");
 
 	try {
-		Genode::Lock::Guard guard(Elf_object::lock());
+		Genode::Lock::Guard guard(shared_object_lock());
 
 		/* update bind now variable */
 		bind_now = (flags & Shared_object::NOW) ? true : false;
@@ -1150,7 +1161,7 @@ Genode::Shared_object::~Shared_object()
 	if (verbose_shared)
 		PDBG("close");
 
-	Genode::Lock::Guard guard(Elf_object::lock());
+	Genode::Lock::Guard guard(shared_object_lock());
 	destroy(Genode::env()->heap(), to_root(_handle));
 }
 

repos/libports/run/ldso.run

@@ -120,6 +120,10 @@ compare_output_to {
 [init -> test-ldso] ------------
 [init -> test-ldso] 'Object' called: good
 [init -> test-ldso] 
+[init -> test-ldso] Shared-object API
+[init -> test-ldso] -----------------
+[init -> test-ldso] Global object constructed
+[init -> test-ldso] 
 [init -> test-ldso] Destruction
 [init -> test-ldso] -----------
 [init -> test-ldso] ~Lib_2_local 55667785

repos/libports/src/test/ldso/lib_dl.cc

@@ -1,6 +1,43 @@
+/*
+ * \brief  Test for the use of 'Shared_object' API
+ * \author Sebastian Sumpf
+ * \author Norman Feske
+ * \date   2014-05-20
+ */
+
+/*
+ * Copyright (C) 2014-2015 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+/* Genode includes */
 #include <base/printf.h>
+
+/* test-local includes */
 #include "test-ldso.h"
 
+using namespace Genode;
+
+struct Global_object
+{
+	Global_object()
+	{
+		Genode::printf("Global object constructed\n");
+	}
+};
+
+/*
+ * The 'global_object' is expected to be construced at the load time of the
+ * shared object.
+ */
+Global_object global_object;
+
+
+/*
+ * XXX currently untested
+ */
 extern "C" void lib_dl_symbol()
 {
 	Genode::printf("called (from '%s')\n", __func__);

repos/libports/src/test/ldso/main.cc

@@ -14,6 +14,8 @@
 #include <base/printf.h>
 #include <rom_session/connection.h>
 #include <base/env.h>
+#include <base/shared_object.h>
+
 using namespace Genode;
 
 /* shared-lib includes */
@@ -160,6 +162,23 @@ static void test_dynamic_cast()
 }
 
 
+/***********************
+ ** Shared-object API **
+ ***********************/
+
+static void test_shared_object_api()
+{
+	/*
+	 * When loading the shared object, we expect the global constructor
+	 * that is present in the library to print a message.
+	 *
+	 * 'lib_dl_so' is a local variable such that its destructor is called
+	 * when leaving the scope of the function.
+	 */
+	Shared_object lib_dl_so("test-ldso_lib_dl.lib.so");
+}
+
+
 /**
  * Main function of LDSO test
  */
@@ -229,6 +248,10 @@ int main(int argc, char **argv)
 	test_dynamic_cast();
 	printf("\n");
 
+	printf("Shared-object API\n");
+	printf("-----------------\n");
+	test_shared_object_api();
+	printf("\n");
 
 	printf("Destruction\n");
 	printf("-----------\n");