Fix symbol lookup order during relocation

  Relocate symbol against DF_1_GLOBAL shared libraries
  loaded before this shared library. This includes
  main executable, ld_preloads and other libraries
  that have DF_1_GLOBAL flag set.

Bug: 2643900
Bug: 15432753
Bug: 18186310

(cherry picked from commit d225a5e65223b375a63548c4b780f04d8f3d7b60)

Change-Id: I4e889cdf2dfbf8230b0790053d311ee6b0d0ee2d

1 files changed, 72 insertions, 0 deletions

diff --git a/tests/dl_test.cpp b/tests/dl_test.cpp
new file mode 100644
index 000000000..74c7b510f
--- /dev/null
+++ b/tests/dl_test.cpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include <dlfcn.h>
+#include <libgen.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#include <string>
+
+extern "C" int main_global_default_serial() {
+  return 3370318;
+}
+
+extern "C" int main_global_protected_serial() {
+  return 2716057;
+}
+
+// The following functions are defined in DT_NEEDED
+// libdl_preempt_test.so library.
+
+// This one calls main_global_default_serial
+extern "C" int main_global_default_get_serial();
+
+// This one calls main_global_protected_serial
+extern "C" int main_global_protected_get_serial();
+
+// This one calls lib_global_default_serial
+extern "C" int lib_global_default_get_serial();
+
+// This one calls lib_global_protected_serial
+extern "C" int lib_global_protected_get_serial();
+
+// This test verifies that the global default function
+// main_global_default_serial() is preempted by
+// the function defined above.
+TEST(dl, main_preempts_global_default) {
+  ASSERT_EQ(3370318, main_global_default_get_serial());
+}
+
+// This one makes sure that the global protected
+// symbols do not get preempted
+TEST(dl, main_does_not_preempt_global_protected) {
+  ASSERT_EQ(3370318, main_global_protected_get_serial());
+}
+
+// check same things for lib
+TEST(dl, lib_preempts_global_default) {
+  ASSERT_EQ(3370318, lib_global_default_get_serial());
+}
+
+TEST(dl, lib_does_not_preempt_global_protected) {
+  ASSERT_EQ(3370318, lib_global_protected_get_serial());
+}
+
+// TODO: Add tests for LD_PRELOADs