Enable loading native libraries with RTLD_DEEPBIND

base/native_library_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/files/file_path.h"
 #include "base/native_library.h"
+#include "base/path_service.h"
+#include "build/build_config.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_WIN)
+#define EXPORT __declspec(dllexport)
+#else
+#define EXPORT __attribute__((visibility("default")))
+#endif
+
+// This symbol name must match the exported symbol in
+// native_library_test_library.cc.
+int EXPORT g_native_library_test_symbol = 0;
+
 namespace base {
 
 const FilePath::CharType kDummyLibraryPath[] =
     FILE_PATH_LITERAL("dummy_library");
 
 TEST(NativeLibraryTest, LoadFailure) {
   NativeLibraryLoadError error;
   EXPECT_FALSE(LoadNativeLibrary(FilePath(kDummyLibraryPath), &error));
   EXPECT_FALSE(error.ToString().empty());
 }
@@ skipping 10 matching lines @@
 #elif defined(OS_MACOSX)
       "libmylib.dylib";
 #elif defined(OS_POSIX)
       "libmylib.so";
 #elif defined(OS_WIN)
       "mylib.dll";
 #endif
   EXPECT_EQ(kExpectedName, GetNativeLibraryName("mylib"));
 }
 
+#if !defined(OS_IOS)
+
+const char kTestLibraryName[] =
+#if defined(OS_MACOSX)
+    "libnative_library_test_library.dylib";
+#elif defined(OS_ANDROID)
+    "libnative_library_test_library.cr.so";

[Primiano Tucci (use gerrit), 2016/08/24 22:14:09]

.cr.so should be only for component builds.
Also looks liek you don't support android, why bothering about this test on non
supported platforms?

[Ken Rockot(use gerrit already), 2016/08/24 23:23:57]

I suppose we don't need to support it now, but I wouldn't rule out Android
support in the future. Doesn't seem like it should be much effort to ensure this
behavior just works on Android anyway?

+#elif defined(OS_POSIX)
+    "libnative_library_test_library.so";
+#elif defined(OS_WIN)
+    "native_library_test_library.dll";
+#endif
+
+class TestLibrary {
+ public:
+  explicit TestLibrary(
+      const NativeLibraryOptions& options = NativeLibraryOptions())
+      : library_(nullptr) {
+    base::FilePath exe_path;
+    CHECK(base::PathService::Get(base::DIR_EXE, &exe_path));
+
+    library_ = LoadNativeLibraryWithOptions(
+        exe_path.AppendASCII(kTestLibraryName), options, nullptr);
+    CHECK(library_);
+  }
+
+  ~TestLibrary() {
+    UnloadNativeLibrary(library_);
+  }
+
+  int GetTestValue() {
+    return GetFunction<int(*)()>("GetTestValue")();
+  }
+
+  bool IsSameTestSymbolAddress(int* address) {
+    return GetFunction<bool(*)(int*)>("IsSameTestSymbolAddress")(address);
+  }
+
+ private:
+  template <typename FuncType>
+  FuncType GetFunction(const char* name) {
+    FuncType func = reinterpret_cast<FuncType>(
+        GetFunctionPointerFromNativeLibrary(library_, name));
+    CHECK(func);
+    return func;
+  }
+
+  NativeLibrary library_;
+};
+
+// Verifies that we can load a native library and resolve its exported symbols.
+TEST(NativeLibraryTest, LoadLibrary) {
+  TestLibrary library;
+  EXPECT_EQ(42, library.GetTestValue());
+}
+
+// Verifies that if we load a native library which exports some symbol also
+// exported by the main binary, the native library resolves the symbol to its
+// own local definition. Note that on some POSIX builds this may not be the
+// default behavior, so the |prefer_own_symbols| option must be used to opt in.
+TEST(NativeLibraryTest, LoadLibraryPreferOwnSymbols) {

[Primiano Tucci (use gerrit), 2016/08/24 22:14:09]

I think it's just clear if this is #ifdef OS_LINUX, not sure
EXPECT_GLOBAL_RTLD_BEHAVIOR makes it easier to read.

[Ken Rockot(use gerrit already), 2016/08/24 23:23:57]

see comment in BUILD.gn

+#if defined(EXPECT_GLOBAL_RTLD_BEHAVIOR)
+  // NOTE: This is only defined on non-Android POSIX builds which use gold for
+  // linking. Otherwise we don't expect this behavior.
+  {
+    TestLibrary library;
+    EXPECT_TRUE(library.IsSameTestSymbolAddress(&g_native_library_test_symbol));
+  }
+#endif  // defined(EXPECT_GLOBAL_RTLD_BEHAVIOR)
+
+  NativeLibraryOptions options;
+  options.prefer_own_symbols = true;
+  TestLibrary library(options);
+  EXPECT_FALSE(library.IsSameTestSymbolAddress(&g_native_library_test_symbol));
+}
+
+#endif  // !defined(OS_IOS)
+
 }  // namespace base