Add support for protected local symbol lookup.

Bug: http://code.google.com/p/android/issues/detail?id=66048
Change-Id: Ib334223df27adad9477fb241ab099c5e26df4a7d

5 files changed, 121 insertions, 0 deletions

diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index 8b89183..18963cf 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -50,6 +50,20 @@ TEST(dlfcn, dlsym_in_self) {
   ASSERT_EQ(0, dlclose(self));
 }
 
+TEST(dlfcn, dlsym_local_symbol) {
+  void* handle = dlopen("libtest_local_symbol.so", RTLD_NOW);
+  ASSERT_TRUE(handle != NULL);
+  dlerror();
+  void* sym = dlsym(handle, "private_taxicab_number");
+  ASSERT_TRUE(sym == NULL);
+  ASSERT_STREQ("undefined symbol: private_taxicab_number", dlerror());
+
+  uint32_t (*f)(void);
+  f = reinterpret_cast<uint32_t (*)(void)>(dlsym(handle, "dlsym_local_symbol_get_taxicab_number_using_dlsym"));
+  ASSERT_TRUE(f != NULL);
+  ASSERT_EQ(1729, f());
+}
+
 TEST(dlfcn, dlopen_noload) {
   void* handle = dlopen("libtest_simple.so", RTLD_NOW | RTLD_NOLOAD);
   ASSERT_TRUE(handle == NULL);
diff --git a/tests/libs/Android.mk b/tests/libs/Android.mk
index 67ea562..efce5b5 100644
--- a/tests/libs/Android.mk
+++ b/tests/libs/Android.mk
@@ -88,6 +88,20 @@ build_type := target
 build_target := SHARED_LIBRARY
 include $(TEST_PATH)/Android.build.mk
 
+# -----------------------------------------------------------------------------
+# Library used to test local symbol lookup
+# -----------------------------------------------------------------------------
+libtest_local_symbol_src_files := \
+    dlsym_local_symbol_private.cpp \
+    dlsym_local_symbol_public.cpp
+
+module := libtest_local_symbol
+build_target := SHARED_LIBRARY
+libtest_local_symbol_ldflags := -Wl,--version-script=$(LOCAL_PATH)/dlsym_local_symbol.map
+libtest_local_symbol_cppflags := -std=gnu++11
+libtest_local_symbol_shared_libraries_target := libdl
+build_type := target
+include $(TEST_PATH)/Android.build.mk
 
 # -----------------------------------------------------------------------------
 # Library used by atexit tests
diff --git a/tests/libs/dlsym_local_symbol.map b/tests/libs/dlsym_local_symbol.map
new file mode 100644
index 0000000..58a2299
--- /dev/null
+++ b/tests/libs/dlsym_local_symbol.map
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2014 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.
+ */
+LIBTEST_LOCAL_SYMBOL_1.0 {
+  global:
+    dlsym_local_symbol_get_taxicab_number;
+    dlsym_local_symbol_get_taxicab_number_using_dlsym;
+  local:
+    *;
+};
diff --git a/tests/libs/dlsym_local_symbol_private.cpp b/tests/libs/dlsym_local_symbol_private.cpp
new file mode 100644
index 0000000..2587508
--- /dev/null
+++ b/tests/libs/dlsym_local_symbol_private.cpp
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2014 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 <stdlib.h>
+#include <dlfcn.h>
+#include <stdio.h>
+
+// This symbol is declared local in
+// the linker version map: libdlsym_local_symbol.map.
+// It should not be visible from the outside.
+extern "C" const uint32_t __attribute__ ((visibility ("protected"))) private_taxicab_number = 1729;
diff --git a/tests/libs/dlsym_local_symbol_public.cpp b/tests/libs/dlsym_local_symbol_public.cpp
new file mode 100644
index 0000000..d9da32a
--- /dev/null
+++ b/tests/libs/dlsym_local_symbol_public.cpp
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2014 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 <stdlib.h>
+#include <dlfcn.h>
+#include <stdio.h>
+
+extern const uint32_t private_taxicab_number;
+
+extern "C" {
+uint32_t dlsym_local_symbol_get_taxicab_number();
+uint32_t dlsym_local_symbol_get_taxicab_number_using_dlsym();
+}
+
+uint32_t dlsym_local_symbol_get_taxicab_number() {
+  return private_taxicab_number;
+}
+
+// Let's make sure that dlsym works correctly for local symbol
+uint32_t dlsym_local_symbol_get_taxicab_number_using_dlsym() {
+  dlerror();
+  uint32_t* ptr = reinterpret_cast<uint32_t*>(dlsym(RTLD_DEFAULT, "private_taxicab_number"));
+  if (ptr == nullptr) {
+    const char* dlerr = dlerror();
+    if (dlerr != nullptr) {
+      fprintf(stderr, "dlsym error: %s\n", dlerr);
+    } else {
+      fprintf(stderr, "dlsym returned NULL with no dlerror.\n");
+    }
+    return 0;
+  }
+
+  return *ptr;
+}