| /* |
| * Copyright (C) 2021 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 <dlfcn.h> |
| |
| #include <cstdlib> |
| #include <iostream> |
| #include <string> |
| |
| #include <android/dlext.h> |
| |
| extern "C" { |
| enum { |
| ANDROID_NAMESPACE_TYPE_REGULAR = 0, |
| ANDROID_NAMESPACE_TYPE_ISOLATED = 1, |
| ANDROID_NAMESPACE_TYPE_SHARED = 2, |
| }; |
| |
| extern struct android_namespace_t* android_create_namespace( |
| const char* name, const char* ld_library_path, const char* default_library_path, |
| uint64_t type, const char* permitted_when_isolated_path, |
| struct android_namespace_t* parent); |
| } // extern "C" |
| |
| static void* load(const std::string& libname); |
| |
| int main(int argc, char* argv[]) { |
| if (argc < 2) { |
| std::cout << "Usage:\n"; |
| std::cout << " " << argv[0] << " LIBNAME [ARGS...]\n"; |
| return EXIT_FAILURE; |
| } |
| |
| const char* libname = argv[1]; |
| void* handle = load(libname); |
| if (handle == nullptr) { |
| std::cerr << "Failed to load " << libname << ": " << dlerror() << "\n"; |
| return EXIT_FAILURE; |
| } |
| |
| int (*entry)(int argc, char* argv[]) = nullptr; |
| entry = reinterpret_cast<decltype(entry)>(dlsym(handle, "android_native_main")); |
| if (entry == nullptr) { |
| std::cerr << "Failed to find entrypoint `android_native_main`: " << dlerror() << "\n"; |
| return EXIT_FAILURE; |
| } |
| |
| return entry(argc - 1, argv + 1); |
| } |
| |
| // Create a new linker namespace whose search path is set to the directory of the library. Then |
| // load it from there. Returns the handle to the loaded library if successful. Returns nullptr |
| // if failed. |
| void* load(const std::string& libname) { |
| // Parent as nullptr means the default namespace |
| android_namespace_t* parent = nullptr; |
| // The search paths of the new namespace are inherited from the parent namespace. |
| const uint64_t type = ANDROID_NAMESPACE_TYPE_SHARED; |
| // The directory of the library is appended to the search paths |
| const std::string libdir = libname.substr(0, libname.find_last_of("/")); |
| const char* ld_library_path = libdir.c_str(); |
| const char* default_library_path = libdir.c_str(); |
| |
| android_namespace_t* new_ns = nullptr; |
| new_ns = android_create_namespace("microdroid_app", ld_library_path, default_library_path, type, |
| /* permitted_when_isolated_path */ nullptr, parent); |
| if (new_ns == nullptr) { |
| std::cerr << "Failed to create linker namespace: " << dlerror() << "\n"; |
| return nullptr; |
| } |
| |
| const android_dlextinfo info = { |
| .flags = ANDROID_DLEXT_USE_NAMESPACE, |
| .library_namespace = new_ns, |
| }; |
| return android_dlopen_ext(libname.c_str(), RTLD_NOW, &info); |
| } |