LibNativeBridge: Version 2 (e2452b4b) · Commits · e / os / android_system_core

include/nativebridge/native_bridge.h

+42 −0

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@
		#define NATIVE_BRIDGE_H_

		#include "jni.h"
		#include <signal.h>
		#include <stdint.h>
		#include <sys/types.h>

		@@ -26,6 +27,12 @@ namespace android {
		struct NativeBridgeRuntimeCallbacks;
		struct NativeBridgeRuntimeValues;

		// Function pointer type for sigaction. This is mostly the signature of a signal handler, except
		// for the return type. The runtime needs to know whether the signal was handled or should be given
		// to the chain.
		typedef bool (NativeBridgeSignalHandlerFn)(int, siginfo_t, void*);


		// Open the native bridge, if any. Should be called by Runtime::Init(). A null library filename
		// signals that we do not want to load a native bridge.
		bool LoadNativeBridge(const char* native_bridge_library_filename,
		@@ -63,6 +70,16 @@ void* NativeBridgeGetTrampoline(void* handle, const char* name, const char* shor
		// True if native library is valid and is for an ABI that is supported by native bridge.
		bool NativeBridgeIsSupported(const char* libpath);

		// Returns the version number of the native bridge. This information is available after a
		// successful LoadNativeBridge() and before closing it, that is, as long as NativeBridgeAvailable()
		// returns true. Returns 0 otherwise.
		uint32_t NativeBridgeGetVersion();

		// Returns a signal handler that the bridge would like to be managed. Only valid for a native
		// bridge supporting the version 2 interface. Will return null if the bridge does not support
		// version 2, or if it doesn't have a signal handler it wants to be known.
		NativeBridgeSignalHandlerFn NativeBridgeGetSignalHandler(int signal);

		// Returns whether we have seen a native bridge error. This could happen because the library
		// was not found, rejected, could not be initialized and so on.
		//
		@@ -127,6 +144,31 @@ struct NativeBridgeCallbacks {
		// NULL if not supported by native bridge.
		// Otherwise, return all environment values to be set after fork.
		const struct NativeBridgeRuntimeValues* (getAppEnv)(const char instruction_set);

		// Added callbacks in version 2.

		// Check whether the bridge is compatible with the given version. A bridge may decide not to be
		// forwards- or backwards-compatible, and libnativebridge will then stop using it.
		//
		// Parameters:
		// bridge_version [IN] the version of libnativebridge.
		// Returns:
		// true iff the native bridge supports the given version of libnativebridge.
		bool (*isCompatibleWith)(uint32_t bridge_version);

		// A callback to retrieve a native bridge's signal handler for the specified signal. The runtime
		// will ensure that the signal handler is being called after the runtime's own handler, but before
		// all chained handlers. The native bridge should not try to install the handler by itself, as
		// that will potentially lead to cycles.
		//
		// Parameters:
		// signal [IN] the signal for which the handler is asked for. Currently, only SIGSEGV is
		// supported by the runtime.
		// Returns:
		// NULL if the native bridge doesn't use a handler or doesn't want it to be managed by the
		// runtime.
		// Otherwise, a pointer to the signal handler.
		NativeBridgeSignalHandlerFn (*getSignalHandler)(int signal);
		};

		// Runtime interfaces to native bridge.

libnativebridge/native_bridge.cc

+36 −6

Original line number	Diff line number	Diff line
		@@ -83,7 +83,7 @@ static bool had_error = false;
		static void* native_bridge_handle = nullptr;
		// Pointer to the callbacks. Available as soon as LoadNativeBridge succeeds, but only initialized
		// later.
		static NativeBridgeCallbacks* callbacks = nullptr;
		static const NativeBridgeCallbacks* callbacks = nullptr;
		// Callbacks provided by the environment to the bridge. Passed to LoadNativeBridge.
		static const NativeBridgeRuntimeCallbacks* runtime_callbacks = nullptr;

		@@ -96,7 +96,7 @@ static char* app_code_cache_dir = nullptr;
		// and hard code the directory name again here.
		static constexpr const char* kCodeCacheDir = "code_cache";

		static constexpr uint32_t kNativeBridgeCallbackVersion = 1;
		static constexpr uint32_t kLibNativeBridgeVersion = 2;

		// 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._-].
		@@ -121,7 +121,9 @@ bool NativeBridgeNameAcceptable(const char* nb_library_filename) {
		// 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);
		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.
		@@ -139,8 +141,22 @@ bool NativeBridgeNameAcceptable(const char* nb_library_filename) {
		}
		}

		static bool VersionCheck(NativeBridgeCallbacks* cb) {
		return cb != nullptr && cb->version == kNativeBridgeCallbackVersion;
		static bool VersionCheck(const NativeBridgeCallbacks* cb) {
		// Libnativebridge is now designed to be forward-compatible. So only "0" is an unsupported
		// version.
		if (cb == nullptr \|\| cb->version == 0) {
		return false;
		}

		// If this is a v2+ bridge, it may not be forwards- or backwards-compatible. Check.
		if (cb->version >= 2) {
		if (!callbacks->isCompatibleWith(kLibNativeBridgeVersion)) {
		// TODO: Scan which version is supported, and fall back to handle it.
		return false;
		}
		}

		return true;
		}

		static void CloseNativeBridge(bool with_error) {
		@@ -321,7 +337,7 @@ static void SetCpuAbi(JNIEnv* env, jclass build_class, const char* field, const
		}

		// Set up the environment for the bridged app.
		static void SetupEnvironment(NativeBridgeCallbacks* callbacks, JNIEnv* env, const char* isa) {
		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.");
		@@ -485,4 +501,18 @@ bool NativeBridgeIsSupported(const char* libpath) {
		return false;
		}

		uint32_t NativeBridgeGetVersion() {
		if (NativeBridgeAvailable()) {
		return callbacks->version;
		}
		return 0;
		}

		NativeBridgeSignalHandlerFn NativeBridgeGetSignalHandler(int signal) {
		if (NativeBridgeInitialized() && callbacks->version >= 2) {
		return callbacks->getSignalHandler(signal);
		}
		return nullptr;
		}

		}; // namespace android

libnativebridge/tests/Android.mk

+2 −0

Original line number	Diff line number	Diff line
		@@ -11,6 +11,8 @@ test_src_files := \
		CodeCacheExists_test.cpp \
		CompleteFlow_test.cpp \
		InvalidCharsNativeBridge_test.cpp \
		NativeBridge2Signal_test.cpp \
		NativeBridgeVersion_test.cpp \
		NeedsNativeBridge_test.cpp \
		PreInitializeNativeBridge_test.cpp \
		PreInitializeNativeBridgeFail1_test.cpp \

libnativebridge/tests/Android.nativebridge-dummy.mk

+36 −0

Original line number	Diff line number	Diff line
		@@ -32,3 +32,39 @@ LOCAL_LDFLAGS := -ldl
		LOCAL_MULTILIB := both

		include $(BUILD_HOST_SHARED_LIBRARY)


		# v2.

		NATIVE_BRIDGE2_COMMON_SRC_FILES := \
		DummyNativeBridge2.cpp

		# Shared library for target
		# ========================================================
		include $(CLEAR_VARS)

		LOCAL_MODULE:= libnativebridge2-dummy

		LOCAL_SRC_FILES:= $(NATIVE_BRIDGE2_COMMON_SRC_FILES)
		LOCAL_CLANG := true
		LOCAL_CFLAGS += -Werror -Wall
		LOCAL_CPPFLAGS := -std=gnu++11 -fvisibility=protected
		LOCAL_LDFLAGS := -ldl
		LOCAL_MULTILIB := both

		include $(BUILD_SHARED_LIBRARY)

		# Shared library for host
		# ========================================================
		include $(CLEAR_VARS)

		LOCAL_MODULE:= libnativebridge2-dummy

		LOCAL_SRC_FILES:= $(NATIVE_BRIDGE2_COMMON_SRC_FILES)
		LOCAL_CLANG := true
		LOCAL_CFLAGS += -Werror -Wall
		LOCAL_CPPFLAGS := -std=gnu++11 -fvisibility=protected
		LOCAL_LDFLAGS := -ldl
		LOCAL_MULTILIB := both

		include $(BUILD_HOST_SHARED_LIBRARY)

libnativebridge/tests/DummyNativeBridge2.cpp

0 → 100644

+76 −0

Original line number	Diff line number	Diff line
		/*
		* 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.
		*/

		// A dummy implementation of the native-bridge interface.

		#include "nativebridge/native_bridge.h"

		#include <signal.h>

		// NativeBridgeCallbacks implementations
		extern "C" bool native_bridge2_initialize(const android::NativeBridgeRuntimeCallbacks* /* art_cbs */,
		const char* /* app_code_cache_dir */,
		const char* /* isa */) {
		return true;
		}

		extern "C" void* native_bridge2_loadLibrary(const char* /* libpath /, int / flag */) {
		return nullptr;
		}

		extern "C" void* native_bridge2_getTrampoline(void* /* handle /, const char /* name */,
		const char* /* shorty /, uint32_t / len */) {
		return nullptr;
		}

		extern "C" bool native_bridge2_isSupported(const char* /* libpath */) {
		return false;
		}

		extern "C" const struct android::NativeBridgeRuntimeValues* native_bridge2_getAppEnv(
		const char* /* abi */) {
		return nullptr;
		}

		extern "C" bool native_bridge2_is_compatible_compatible_with(uint32_t version) {
		// For testing, allow 1 and 2, but disallow 3+.
		return version <= 2;
		}

		static bool native_bridge2_dummy_signal_handler(int, siginfo_t, void) {
		// TODO: Implement something here. We'd either have to have a death test with a log here, or
		// we'd have to be able to resume after the faulting instruction...
		return true;
		}

		extern "C" android::NativeBridgeSignalHandlerFn native_bridge2_get_signal_handler(int signal) {
		if (signal == SIGSEGV) {
		return &native_bridge2_dummy_signal_handler;
		}
		return nullptr;
		}

		android::NativeBridgeCallbacks NativeBridgeItf {
		.version = 2,
		.initialize = &native_bridge2_initialize,
		.loadLibrary = &native_bridge2_loadLibrary,
		.getTrampoline = &native_bridge2_getTrampoline,
		.isSupported = &native_bridge2_isSupported,
		.getAppEnv = &native_bridge2_getAppEnv,
		.isCompatibleWith = &native_bridge2_is_compatible_compatible_with,
		.getSignalHandler = &native_bridge2_get_signal_handler
		};