| /* |
| * 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. |
| */ |
| |
| #define LOG_TAG "nativebridge" |
| |
| #include "nativebridge/native_bridge.h" |
| |
| #include <dlfcn.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <stdio.h> |
| #include <sys/mount.h> |
| #include <sys/stat.h> |
| #include <unistd.h> |
| |
| #include <cstring> |
| |
| #include <android-base/macros.h> |
| #include <log/log.h> |
| |
| namespace android { |
| |
| #ifdef __APPLE__ |
| template <typename T> |
| void UNUSED(const T&) {} |
| #endif |
| |
| extern "C" { |
| |
| // Environment values required by the apps running with native bridge. |
| struct NativeBridgeRuntimeValues { |
| const char* os_arch; |
| const char* cpu_abi; |
| const char* cpu_abi2; |
| const char* *supported_abis; |
| int32_t abi_count; |
| }; |
| |
| // The symbol name exposed by native-bridge with the type of NativeBridgeCallbacks. |
| static constexpr const char* kNativeBridgeInterfaceSymbol = "NativeBridgeItf"; |
| |
| enum class NativeBridgeState { |
| kNotSetup, // Initial state. |
| kOpened, // After successful dlopen. |
| kPreInitialized, // After successful pre-initialization. |
| kInitialized, // After successful initialization. |
| kClosed // Closed or errors. |
| }; |
| |
| static constexpr const char* kNotSetupString = "kNotSetup"; |
| static constexpr const char* kOpenedString = "kOpened"; |
| static constexpr const char* kPreInitializedString = "kPreInitialized"; |
| static constexpr const char* kInitializedString = "kInitialized"; |
| static constexpr const char* kClosedString = "kClosed"; |
| |
| static const char* GetNativeBridgeStateString(NativeBridgeState state) { |
| switch (state) { |
| case NativeBridgeState::kNotSetup: |
| return kNotSetupString; |
| |
| case NativeBridgeState::kOpened: |
| return kOpenedString; |
| |
| case NativeBridgeState::kPreInitialized: |
| return kPreInitializedString; |
| |
| case NativeBridgeState::kInitialized: |
| return kInitializedString; |
| |
| case NativeBridgeState::kClosed: |
| return kClosedString; |
| } |
| } |
| |
| // Current state of the native bridge. |
| static NativeBridgeState state = NativeBridgeState::kNotSetup; |
| |
| // The version of NativeBridge implementation. |
| // Different Nativebridge interface needs the service of different version of |
| // Nativebridge implementation. |
| // Used by isCompatibleWith() which is introduced in v2. |
| enum NativeBridgeImplementationVersion { |
| // first version, not used. |
| DEFAULT_VERSION = 1, |
| // The version which signal semantic is introduced. |
| SIGNAL_VERSION = 2, |
| // The version which namespace semantic is introduced. |
| NAMESPACE_VERSION = 3, |
| // The version with vendor namespaces |
| VENDOR_NAMESPACE_VERSION = 4, |
| }; |
| |
| // Whether we had an error at some point. |
| static bool had_error = false; |
| |
| // Handle of the loaded library. |
| static void* native_bridge_handle = nullptr; |
| // Pointer to the callbacks. Available as soon as LoadNativeBridge succeeds, but only initialized |
| // later. |
| static const NativeBridgeCallbacks* callbacks = nullptr; |
| // Callbacks provided by the environment to the bridge. Passed to LoadNativeBridge. |
| static const NativeBridgeRuntimeCallbacks* runtime_callbacks = nullptr; |
| |
| // The app's code cache directory. |
| static char* app_code_cache_dir = nullptr; |
| |
| // Code cache directory (relative to the application private directory) |
| // Ideally we'd like to call into framework to retrieve this name. However that's considered an |
| // implementation detail and will require either hacks or consistent refactorings. We compromise |
| // and hard code the directory name again here. |
| static constexpr const char* kCodeCacheDir = "code_cache"; |
| |
| // Characters allowed in a native bridge filename. The first character must |
| // be in [a-zA-Z] (expected 'l' for "libx"). The rest must be in [a-zA-Z0-9._-]. |
| static bool CharacterAllowed(char c, bool first) { |
| if (first) { |
| return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z'); |
| } else { |
| return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || ('0' <= c && c <= '9') || |
| (c == '.') || (c == '_') || (c == '-'); |
| } |
| } |
| |
| static void ReleaseAppCodeCacheDir() { |
| if (app_code_cache_dir != nullptr) { |
| delete[] app_code_cache_dir; |
| app_code_cache_dir = nullptr; |
| } |
| } |
| |
| // We only allow simple names for the library. It is supposed to be a file in |
| // /system/lib or /vendor/lib. Only allow a small range of characters, that is |
| // names consisting of [a-zA-Z0-9._-] and starting with [a-zA-Z]. |
| bool NativeBridgeNameAcceptable(const char* nb_library_filename) { |
| const char* ptr = nb_library_filename; |
| if (*ptr == 0) { |
| // Emptry string. Allowed, means no native bridge. |
| return true; |
| } else { |
| // First character must be [a-zA-Z]. |
| if (!CharacterAllowed(*ptr, true)) { |
| // Found an invalid fist character, don't accept. |
| ALOGE("Native bridge library %s has been rejected for first character %c", |
| nb_library_filename, |
| *ptr); |
| return false; |
| } else { |
| // For the rest, be more liberal. |
| ptr++; |
| while (*ptr != 0) { |
| if (!CharacterAllowed(*ptr, false)) { |
| // Found an invalid character, don't accept. |
| ALOGE("Native bridge library %s has been rejected for %c", nb_library_filename, *ptr); |
| return false; |
| } |
| ptr++; |
| } |
| } |
| return true; |
| } |
| } |
| |
| // The policy of invoking Nativebridge changed in v3 with/without namespace. |
| // Suggest Nativebridge implementation not maintain backward-compatible. |
| static bool isCompatibleWith(const uint32_t version) { |
| // Libnativebridge is now designed to be forward-compatible. So only "0" is an unsupported |
| // version. |
| if (callbacks == nullptr || callbacks->version == 0 || version == 0) { |
| return false; |
| } |
| |
| // If this is a v2+ bridge, it may not be forwards- or backwards-compatible. Check. |
| if (callbacks->version >= SIGNAL_VERSION) { |
| return callbacks->isCompatibleWith(version); |
| } |
| |
| return true; |
| } |
| |
| static void CloseNativeBridge(bool with_error) { |
| state = NativeBridgeState::kClosed; |
| had_error |= with_error; |
| ReleaseAppCodeCacheDir(); |
| } |
| |
| bool LoadNativeBridge(const char* nb_library_filename, |
| const NativeBridgeRuntimeCallbacks* runtime_cbs) { |
| // We expect only one place that calls LoadNativeBridge: Runtime::Init. At that point we are not |
| // multi-threaded, so we do not need locking here. |
| |
| if (state != NativeBridgeState::kNotSetup) { |
| // Setup has been called before. Ignore this call. |
| if (nb_library_filename != nullptr) { // Avoids some log-spam for dalvikvm. |
| ALOGW("Called LoadNativeBridge for an already set up native bridge. State is %s.", |
| GetNativeBridgeStateString(state)); |
| } |
| // Note: counts as an error, even though the bridge may be functional. |
| had_error = true; |
| return false; |
| } |
| |
| if (nb_library_filename == nullptr || *nb_library_filename == 0) { |
| CloseNativeBridge(false); |
| return false; |
| } else { |
| if (!NativeBridgeNameAcceptable(nb_library_filename)) { |
| CloseNativeBridge(true); |
| } else { |
| // Try to open the library. |
| void* handle = dlopen(nb_library_filename, RTLD_LAZY); |
| if (handle != nullptr) { |
| callbacks = reinterpret_cast<NativeBridgeCallbacks*>(dlsym(handle, |
| kNativeBridgeInterfaceSymbol)); |
| if (callbacks != nullptr) { |
| if (isCompatibleWith(NAMESPACE_VERSION)) { |
| // Store the handle for later. |
| native_bridge_handle = handle; |
| } else { |
| callbacks = nullptr; |
| dlclose(handle); |
| ALOGW("Unsupported native bridge interface."); |
| } |
| } else { |
| dlclose(handle); |
| } |
| } |
| |
| // Two failure conditions: could not find library (dlopen failed), or could not find native |
| // bridge interface (dlsym failed). Both are an error and close the native bridge. |
| if (callbacks == nullptr) { |
| CloseNativeBridge(true); |
| } else { |
| runtime_callbacks = runtime_cbs; |
| state = NativeBridgeState::kOpened; |
| } |
| } |
| return state == NativeBridgeState::kOpened; |
| } |
| } |
| |
| bool NeedsNativeBridge(const char* instruction_set) { |
| if (instruction_set == nullptr) { |
| ALOGE("Null instruction set in NeedsNativeBridge."); |
| return false; |
| } |
| return strncmp(instruction_set, ABI_STRING, strlen(ABI_STRING) + 1) != 0; |
| } |
| |
| bool PreInitializeNativeBridge(const char* app_data_dir_in, const char* instruction_set) { |
| if (state != NativeBridgeState::kOpened) { |
| ALOGE("Invalid state: native bridge is expected to be opened."); |
| CloseNativeBridge(true); |
| return false; |
| } |
| |
| if (app_data_dir_in == nullptr) { |
| ALOGE("Application private directory cannot be null."); |
| CloseNativeBridge(true); |
| return false; |
| } |
| |
| // Create the path to the application code cache directory. |
| // The memory will be release after Initialization or when the native bridge is closed. |
| const size_t len = strlen(app_data_dir_in) + strlen(kCodeCacheDir) + 2; // '\0' + '/' |
| app_code_cache_dir = new char[len]; |
| snprintf(app_code_cache_dir, len, "%s/%s", app_data_dir_in, kCodeCacheDir); |
| |
| // Bind-mount /system/lib{,64}/<isa>/cpuinfo to /proc/cpuinfo. |
| // Failure is not fatal and will keep the native bridge in kPreInitialized. |
| state = NativeBridgeState::kPreInitialized; |
| |
| #ifndef __APPLE__ |
| if (instruction_set == nullptr) { |
| return true; |
| } |
| size_t isa_len = strlen(instruction_set); |
| if (isa_len > 10) { |
| // 10 is a loose upper bound on the currently known instruction sets (a tight bound is 7 for |
| // x86_64 [including the trailing \0]). This is so we don't have to change here if there will |
| // be another instruction set in the future. |
| ALOGW("Instruction set %s is malformed, must be less than or equal to 10 characters.", |
| instruction_set); |
| return true; |
| } |
| |
| // If the file does not exist, the mount command will fail, |
| // so we save the extra file existence check. |
| char cpuinfo_path[1024]; |
| |
| #if defined(__ANDROID__) |
| snprintf(cpuinfo_path, sizeof(cpuinfo_path), "/system/lib" |
| #ifdef __LP64__ |
| "64" |
| #endif // __LP64__ |
| "/%s/cpuinfo", instruction_set); |
| #else // !__ANDROID__ |
| // To be able to test on the host, we hardwire a relative path. |
| snprintf(cpuinfo_path, sizeof(cpuinfo_path), "./cpuinfo"); |
| #endif |
| |
| // Bind-mount. |
| if (TEMP_FAILURE_RETRY(mount(cpuinfo_path, // Source. |
| "/proc/cpuinfo", // Target. |
| nullptr, // FS type. |
| MS_BIND, // Mount flags: bind mount. |
| nullptr)) == -1) { // "Data." |
| ALOGW("Failed to bind-mount %s as /proc/cpuinfo: %s", cpuinfo_path, strerror(errno)); |
| } |
| #else // __APPLE__ |
| UNUSED(instruction_set); |
| ALOGW("Mac OS does not support bind-mounting. Host simulation of native bridge impossible."); |
| #endif |
| |
| return true; |
| } |
| |
| static void SetCpuAbi(JNIEnv* env, jclass build_class, const char* field, const char* value) { |
| if (value != nullptr) { |
| jfieldID field_id = env->GetStaticFieldID(build_class, field, "Ljava/lang/String;"); |
| if (field_id == nullptr) { |
| env->ExceptionClear(); |
| ALOGW("Could not find %s field.", field); |
| return; |
| } |
| |
| jstring str = env->NewStringUTF(value); |
| if (str == nullptr) { |
| env->ExceptionClear(); |
| ALOGW("Could not create string %s.", value); |
| return; |
| } |
| |
| env->SetStaticObjectField(build_class, field_id, str); |
| } |
| } |
| |
| // Set up the environment for the bridged app. |
| static void SetupEnvironment(const NativeBridgeCallbacks* callbacks, JNIEnv* env, const char* isa) { |
| // Need a JNIEnv* to do anything. |
| if (env == nullptr) { |
| ALOGW("No JNIEnv* to set up app environment."); |
| return; |
| } |
| |
| // Query the bridge for environment values. |
| const struct NativeBridgeRuntimeValues* env_values = callbacks->getAppEnv(isa); |
| if (env_values == nullptr) { |
| return; |
| } |
| |
| // Keep the JNIEnv clean. |
| jint success = env->PushLocalFrame(16); // That should be small and large enough. |
| if (success < 0) { |
| // Out of memory, really borked. |
| ALOGW("Out of memory while setting up app environment."); |
| env->ExceptionClear(); |
| return; |
| } |
| |
| // Reset CPU_ABI & CPU_ABI2 to values required by the apps running with native bridge. |
| if (env_values->cpu_abi != nullptr || env_values->cpu_abi2 != nullptr || |
| env_values->abi_count >= 0) { |
| jclass bclass_id = env->FindClass("android/os/Build"); |
| if (bclass_id != nullptr) { |
| SetCpuAbi(env, bclass_id, "CPU_ABI", env_values->cpu_abi); |
| SetCpuAbi(env, bclass_id, "CPU_ABI2", env_values->cpu_abi2); |
| } else { |
| // For example in a host test environment. |
| env->ExceptionClear(); |
| ALOGW("Could not find Build class."); |
| } |
| } |
| |
| if (env_values->os_arch != nullptr) { |
| jclass sclass_id = env->FindClass("java/lang/System"); |
| if (sclass_id != nullptr) { |
| jmethodID set_prop_id = env->GetStaticMethodID(sclass_id, "setUnchangeableSystemProperty", |
| "(Ljava/lang/String;Ljava/lang/String;)V"); |
| if (set_prop_id != nullptr) { |
| // Init os.arch to the value reqired by the apps running with native bridge. |
| env->CallStaticVoidMethod(sclass_id, set_prop_id, env->NewStringUTF("os.arch"), |
| env->NewStringUTF(env_values->os_arch)); |
| } else { |
| env->ExceptionClear(); |
| ALOGW("Could not find System#setUnchangeableSystemProperty."); |
| } |
| } else { |
| env->ExceptionClear(); |
| ALOGW("Could not find System class."); |
| } |
| } |
| |
| // Make it pristine again. |
| env->PopLocalFrame(nullptr); |
| } |
| |
| bool InitializeNativeBridge(JNIEnv* env, const char* instruction_set) { |
| // We expect only one place that calls InitializeNativeBridge: Runtime::DidForkFromZygote. At that |
| // point we are not multi-threaded, so we do not need locking here. |
| |
| if (state == NativeBridgeState::kPreInitialized) { |
| // Check for code cache: if it doesn't exist try to create it. |
| struct stat st; |
| if (stat(app_code_cache_dir, &st) == -1) { |
| if (errno == ENOENT) { |
| if (mkdir(app_code_cache_dir, S_IRWXU | S_IRWXG | S_IXOTH) == -1) { |
| ALOGW("Cannot create code cache directory %s: %s.", app_code_cache_dir, strerror(errno)); |
| ReleaseAppCodeCacheDir(); |
| } |
| } else { |
| ALOGW("Cannot stat code cache directory %s: %s.", app_code_cache_dir, strerror(errno)); |
| ReleaseAppCodeCacheDir(); |
| } |
| } else if (!S_ISDIR(st.st_mode)) { |
| ALOGW("Code cache is not a directory %s.", app_code_cache_dir); |
| ReleaseAppCodeCacheDir(); |
| } |
| |
| // If we're still PreInitialized (dind't fail the code cache checks) try to initialize. |
| if (state == NativeBridgeState::kPreInitialized) { |
| if (callbacks->initialize(runtime_callbacks, app_code_cache_dir, instruction_set)) { |
| SetupEnvironment(callbacks, env, instruction_set); |
| state = NativeBridgeState::kInitialized; |
| // We no longer need the code cache path, release the memory. |
| ReleaseAppCodeCacheDir(); |
| } else { |
| // Unload the library. |
| dlclose(native_bridge_handle); |
| CloseNativeBridge(true); |
| } |
| } |
| } else { |
| CloseNativeBridge(true); |
| } |
| |
| return state == NativeBridgeState::kInitialized; |
| } |
| |
| void UnloadNativeBridge() { |
| // We expect only one place that calls UnloadNativeBridge: Runtime::DidForkFromZygote. At that |
| // point we are not multi-threaded, so we do not need locking here. |
| |
| switch(state) { |
| case NativeBridgeState::kOpened: |
| case NativeBridgeState::kPreInitialized: |
| case NativeBridgeState::kInitialized: |
| // Unload. |
| dlclose(native_bridge_handle); |
| CloseNativeBridge(false); |
| break; |
| |
| case NativeBridgeState::kNotSetup: |
| // Not even set up. Error. |
| CloseNativeBridge(true); |
| break; |
| |
| case NativeBridgeState::kClosed: |
| // Ignore. |
| break; |
| } |
| } |
| |
| bool NativeBridgeError() { |
| return had_error; |
| } |
| |
| bool NativeBridgeAvailable() { |
| return state == NativeBridgeState::kOpened |
| || state == NativeBridgeState::kPreInitialized |
| || state == NativeBridgeState::kInitialized; |
| } |
| |
| bool NativeBridgeInitialized() { |
| // Calls of this are supposed to happen in a state where the native bridge is stable, i.e., after |
| // Runtime::DidForkFromZygote. In that case we do not need a lock. |
| return state == NativeBridgeState::kInitialized; |
| } |
| |
| void* NativeBridgeLoadLibrary(const char* libpath, int flag) { |
| if (NativeBridgeInitialized()) { |
| return callbacks->loadLibrary(libpath, flag); |
| } |
| return nullptr; |
| } |
| |
| void* NativeBridgeGetTrampoline(void* handle, const char* name, const char* shorty, |
| uint32_t len) { |
| if (NativeBridgeInitialized()) { |
| return callbacks->getTrampoline(handle, name, shorty, len); |
| } |
| return nullptr; |
| } |
| |
| bool NativeBridgeIsSupported(const char* libpath) { |
| if (NativeBridgeInitialized()) { |
| return callbacks->isSupported(libpath); |
| } |
| return false; |
| } |
| |
| uint32_t NativeBridgeGetVersion() { |
| if (NativeBridgeAvailable()) { |
| return callbacks->version; |
| } |
| return 0; |
| } |
| |
| NativeBridgeSignalHandlerFn NativeBridgeGetSignalHandler(int signal) { |
| if (NativeBridgeInitialized()) { |
| if (isCompatibleWith(SIGNAL_VERSION)) { |
| return callbacks->getSignalHandler(signal); |
| } else { |
| ALOGE("not compatible with version %d, cannot get signal handler", SIGNAL_VERSION); |
| } |
| } |
| return nullptr; |
| } |
| |
| int NativeBridgeUnloadLibrary(void* handle) { |
| if (NativeBridgeInitialized()) { |
| if (isCompatibleWith(NAMESPACE_VERSION)) { |
| return callbacks->unloadLibrary(handle); |
| } else { |
| ALOGE("not compatible with version %d, cannot unload library", NAMESPACE_VERSION); |
| } |
| } |
| return -1; |
| } |
| |
| const char* NativeBridgeGetError() { |
| if (NativeBridgeInitialized()) { |
| if (isCompatibleWith(NAMESPACE_VERSION)) { |
| return callbacks->getError(); |
| } else { |
| return "native bridge implementation is not compatible with version 3, cannot get message"; |
| } |
| } |
| return "native bridge is not initialized"; |
| } |
| |
| bool NativeBridgeIsPathSupported(const char* path) { |
| if (NativeBridgeInitialized()) { |
| if (isCompatibleWith(NAMESPACE_VERSION)) { |
| return callbacks->isPathSupported(path); |
| } else { |
| ALOGE("not compatible with version %d, cannot check via library path", NAMESPACE_VERSION); |
| } |
| } |
| return false; |
| } |
| |
| bool NativeBridgeInitAnonymousNamespace(const char* public_ns_sonames, |
| const char* anon_ns_library_path) { |
| if (NativeBridgeInitialized()) { |
| if (isCompatibleWith(NAMESPACE_VERSION)) { |
| return callbacks->initAnonymousNamespace(public_ns_sonames, anon_ns_library_path); |
| } else { |
| ALOGE("not compatible with version %d, cannot init namespace", NAMESPACE_VERSION); |
| } |
| } |
| |
| return false; |
| } |
| |
| native_bridge_namespace_t* NativeBridgeCreateNamespace(const char* name, |
| const char* ld_library_path, |
| const char* default_library_path, |
| uint64_t type, |
| const char* permitted_when_isolated_path, |
| native_bridge_namespace_t* parent_ns) { |
| if (NativeBridgeInitialized()) { |
| if (isCompatibleWith(NAMESPACE_VERSION)) { |
| return callbacks->createNamespace(name, |
| ld_library_path, |
| default_library_path, |
| type, |
| permitted_when_isolated_path, |
| parent_ns); |
| } else { |
| ALOGE("not compatible with version %d, cannot create namespace %s", NAMESPACE_VERSION, name); |
| } |
| } |
| |
| return nullptr; |
| } |
| |
| bool NativeBridgeLinkNamespaces(native_bridge_namespace_t* from, native_bridge_namespace_t* to, |
| const char* shared_libs_sonames) { |
| if (NativeBridgeInitialized()) { |
| if (isCompatibleWith(NAMESPACE_VERSION)) { |
| return callbacks->linkNamespaces(from, to, shared_libs_sonames); |
| } else { |
| ALOGE("not compatible with version %d, cannot init namespace", NAMESPACE_VERSION); |
| } |
| } |
| |
| return false; |
| } |
| |
| native_bridge_namespace_t* NativeBridgeGetVendorNamespace() { |
| if (!NativeBridgeInitialized() || !isCompatibleWith(VENDOR_NAMESPACE_VERSION)) { |
| return nullptr; |
| } |
| |
| return callbacks->getVendorNamespace(); |
| } |
| |
| void* NativeBridgeLoadLibraryExt(const char* libpath, int flag, native_bridge_namespace_t* ns) { |
| if (NativeBridgeInitialized()) { |
| if (isCompatibleWith(NAMESPACE_VERSION)) { |
| return callbacks->loadLibraryExt(libpath, flag, ns); |
| } else { |
| ALOGE("not compatible with version %d, cannot load library in namespace", NAMESPACE_VERSION); |
| } |
| } |
| return nullptr; |
| } |
| |
| } // extern "C" |
| |
| } // namespace android |