commit f439b5a3186ca0fef1092f45770abc716da9d87a
author Dmitriy Ivanov <dimitry@google.com> Sat May 30 13:04:39 2015 -0700
committer Dmitriy Ivanov <dimitry@google.com> Mon Jun 01 14:33:43 2015 -0700
tree d85508ffcefb14495e90d6e0669440558f753367
parent d70891687d742414d457e41a998726e5eb0a09bd

Fix dlsym(handle_of_main_executable, ...)

  According to man dlopen(3) and posix docs in the case when si is handle
  of the main executable we need to search not only in the executable and its
  dependencies but also in all libraries loaded with RTLD_GLOBAL.

  see also: http://pubs.opengroup.org/onlinepubs/9699919799/functions/dlopen.html

Bug: http://b/21528224
Bug: http://b/17512583
Bug: https://code.google.com/p/android/issues/detail?id=173822
Change-Id: Ib2801367ba48b6f3704da89a6d9f5e6911430013

tests/dlfcn_test.cpp

diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index a5abda7..3c9b8e3 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -145,13 +145,28 @@
   dlclose(preload);
 }
 
+TEST(dlfcn, dlsym_handle_global_sym) {
+  // check that we do not look into global group
+  // when looking up symbol by handle
+  void* handle = dlopen("libtest_empty.so", RTLD_NOW);
+  dlopen("libtest_with_dependency.so", RTLD_NOW | RTLD_GLOBAL);
+  void* sym = dlsym(handle, "getRandomNumber");
+  ASSERT_TRUE(sym == nullptr);
+  ASSERT_SUBSTR("undefined symbol: getRandomNumber", dlerror());
+
+  sym = dlsym(handle, "DlSymTestFunction");
+  ASSERT_TRUE(sym == nullptr);
+  ASSERT_SUBSTR("undefined symbol: DlSymTestFunction", dlerror());
+  dlclose(handle);
+}
+
 TEST(dlfcn, dlsym_with_dependencies) {
   void* handle = dlopen("libtest_with_dependency.so", RTLD_NOW);
-  ASSERT_TRUE(handle != NULL);
+  ASSERT_TRUE(handle != nullptr);
   dlerror();
   // This symbol is in DT_NEEDED library.
   void* sym = dlsym(handle, "getRandomNumber");
-  ASSERT_TRUE(sym != NULL);
+  ASSERT_TRUE(sym != nullptr) << dlerror();
   int (*fn)(void);
   fn = reinterpret_cast<int (*)(void)>(sym);
   EXPECT_EQ(4, fn());
@@ -583,6 +598,15 @@
   // RTLD_GLOBAL implies RTLD_NODELETE, let's check that
   void* sym_after_dlclose = dlsym(RTLD_DEFAULT, "dlopen_testlib_simple_func");
   ASSERT_EQ(sym, sym_after_dlclose);
+
+  // Check if dlsym() for main program's handle searches RTLD_GLOBAL
+  // shared libraries after symbol was not found in the main executable
+  // and dependent libraries.
+  void* handle_for_main_executable = dlopen(nullptr, RTLD_NOW);
+  sym = dlsym(handle_for_main_executable, "dlopen_testlib_simple_func");
+  ASSERT_TRUE(sym != nullptr) << dlerror();
+
+  dlclose(handle_for_main_executable);
 }
 
 // libtest_with_dependency_loop.so -> libtest_with_dependency_loop_a.so ->