libnativebridge/native_bridge.cc - fp2-dev/platform/system/core - Gitiles

 /*
  * 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.
  */

 #include "nativebridge/native_bridge.h"

 #include <cutils/log.h>
 #include <dlfcn.h>
 #include <stdio.h>


 namespace android {

 // 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.
   kInitialized,                     // After successful initialization.
   kClosed                           // Closed or errors.
 };

 static const char* kNotSetupString = "kNotSetup";
 static const char* kOpenedString = "kOpened";
 static const char* kInitializedString = "kInitialized";
 static const char* kClosedString = "kClosed";

 static const char* GetNativeBridgeStateString(NativeBridgeState state) {
   switch (state) {
     case NativeBridgeState::kNotSetup:
       return kNotSetupString;

     case NativeBridgeState::kOpened:
       return kOpenedString;

     case NativeBridgeState::kInitialized:
       return kInitializedString;

     case NativeBridgeState::kClosed:
       return kClosedString;
   }
 }

 // Current state of the native bridge.
 static NativeBridgeState state = NativeBridgeState::kNotSetup;

 // 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 NativeBridgeCallbacks* callbacks = nullptr;
 // Callbacks provided by the environment to the bridge. Passed to LoadNativeBridge.
 static const NativeBridgeRuntimeCallbacks* runtime_callbacks = nullptr;

 // 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 == '-');
   }
 }

 // 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;
   }
 }

 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.
     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) {
     state = NativeBridgeState::kClosed;
     return true;
   } else {
     if (!NativeBridgeNameAcceptable(nb_library_filename)) {
       state = NativeBridgeState::kClosed;
       had_error = 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) {
           // Store the handle for later.
           native_bridge_handle = handle;
         } 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) {
         had_error = true;
         state = NativeBridgeState::kClosed;
       } else {
         runtime_callbacks = runtime_cbs;
         state = NativeBridgeState::kOpened;
       }
     }
     return state == NativeBridgeState::kOpened;
   }
 }

 bool InitializeNativeBridge() {
   // 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::kOpened) {
     // Try to initialize.
     if (callbacks->initialize(runtime_callbacks)) {
       state = NativeBridgeState::kInitialized;
     } else {
       // Unload the library.
       dlclose(native_bridge_handle);
       had_error = true;
       state = NativeBridgeState::kClosed;
     }
   } else {
     had_error = true;
     state = NativeBridgeState::kClosed;
   }

   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::kInitialized:
       // Unload.
       dlclose(native_bridge_handle);
       break;

     case NativeBridgeState::kNotSetup:
       // Not even set up. Error.
       had_error = true;
       break;

     case NativeBridgeState::kClosed:
       // Ignore.
       break;
   }

   state = NativeBridgeState::kClosed;
 }

 bool NativeBridgeError() {
   return had_error;
 }

 bool NativeBridgeAvailable() {
   return state == NativeBridgeState::kOpened || 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;
 }

 };  // namespace android
	/*
	* 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.
	*/

	#include "nativebridge/native_bridge.h"

	#include <cutils/log.h>
	#include <dlfcn.h>
	#include <stdio.h>


	namespace android {

	// 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.
	kInitialized, // After successful initialization.
	kClosed // Closed or errors.
	};

	static const char* kNotSetupString = "kNotSetup";
	static const char* kOpenedString = "kOpened";
	static const char* kInitializedString = "kInitialized";
	static const char* kClosedString = "kClosed";

	static const char* GetNativeBridgeStateString(NativeBridgeState state) {
	switch (state) {
	case NativeBridgeState::kNotSetup:
	return kNotSetupString;

	case NativeBridgeState::kOpened:
	return kOpenedString;

	case NativeBridgeState::kInitialized:
	return kInitializedString;

	case NativeBridgeState::kClosed:
	return kClosedString;
	}
	}

	// Current state of the native bridge.
	static NativeBridgeState state = NativeBridgeState::kNotSetup;

	// 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 NativeBridgeCallbacks* callbacks = nullptr;
	// Callbacks provided by the environment to the bridge. Passed to LoadNativeBridge.
	static const NativeBridgeRuntimeCallbacks* runtime_callbacks = nullptr;

	// 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 == '-');
	}
	}

	// 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;
	}
	}

	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.
	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) {
	state = NativeBridgeState::kClosed;
	return true;
	} else {
	if (!NativeBridgeNameAcceptable(nb_library_filename)) {
	state = NativeBridgeState::kClosed;
	had_error = 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) {
	// Store the handle for later.
	native_bridge_handle = handle;
	} 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) {
	had_error = true;
	state = NativeBridgeState::kClosed;
	} else {
	runtime_callbacks = runtime_cbs;
	state = NativeBridgeState::kOpened;
	}
	}
	return state == NativeBridgeState::kOpened;
	}
	}

	bool InitializeNativeBridge() {
	// 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::kOpened) {
	// Try to initialize.
	if (callbacks->initialize(runtime_callbacks)) {
	state = NativeBridgeState::kInitialized;
	} else {
	// Unload the library.
	dlclose(native_bridge_handle);
	had_error = true;
	state = NativeBridgeState::kClosed;
	}
	} else {
	had_error = true;
	state = NativeBridgeState::kClosed;
	}

	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::kInitialized:
	// Unload.
	dlclose(native_bridge_handle);
	break;

	case NativeBridgeState::kNotSetup:
	// Not even set up. Error.
	had_error = true;
	break;

	case NativeBridgeState::kClosed:
	// Ignore.
	break;
	}

	state = NativeBridgeState::kClosed;
	}

	bool NativeBridgeError() {
	return had_error;
	}

	bool NativeBridgeAvailable() {
	return state == NativeBridgeState::kOpened \|\| 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;
	}

	}; // namespace android