1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <dlfcn.h> 18 19 static const char* g_local_string = "This string is local to root library"; 20 extern "C" const char* g_private_extern_string; 21 extern "C" const char* g_public_extern_string; 22 23 // This is resolved only if public library is in the same namespace as 24 // the root one. It should remain unresolved if looking up for public library 25 // crosses namespace boundary. 26 // 27 // Defined in libnstest_public_internal.so on which libnstest_public.so 28 // depends on 29 extern "C" const char* __attribute__((weak)) internal_extern_string(); 30 31 bool g_dlopened = false; 32 33 extern "C" const char* ns_get_local_string() { 34 return g_local_string; 35 } 36 37 extern "C" const char* ns_get_private_extern_string() { 38 return g_private_extern_string; 39 } 40 41 extern "C" const char* ns_get_public_extern_string() { 42 return g_public_extern_string; 43 } 44 45 extern "C" const char* ns_get_internal_extern_string() { 46 if (internal_extern_string != nullptr) { 47 return internal_extern_string(); 48 } else { 49 return nullptr; 50 } 51 } 52 53 extern "C" const char* ns_get_dlopened_string() { 54 void* handle = dlopen("libnstest_dlopened.so", RTLD_NOW | RTLD_GLOBAL); 55 if (handle == nullptr) { 56 return nullptr; 57 } 58 59 const char** result = static_cast<const char**>(dlsym(handle, "g_private_dlopened_string")); 60 if (result == nullptr) { 61 return nullptr; 62 } else { 63 g_dlopened = true; 64 } 65 66 return *result; 67 } 68
