Add HIDL token passing mechanism.
Test: Mirroring, Camera, Photos, YouTube and Play Movies apps.
Bug: 35442034
Change-Id: I7216f853ad42f115fd00ed9031793d8d1e7d1a03
diff --git a/include/binder/HalToken.h b/include/binder/HalToken.h
new file mode 100644
index 0000000..7ef4f96
--- /dev/null
+++ b/include/binder/HalToken.h
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#ifndef ANDROID_HALTOKEN_H
+#define ANDROID_HALTOKEN_H
+
+#include <binder/Parcel.h>
+#include <hidl/HidlSupport.h>
+
+/**
+ * It is possible to pass a hidl interface via as a binder interface by
+ * providing an appropriate "wrapper" class.
+ *
+ * Terminology:
+ * - `HalToken`: The type for a "token" of a hidl interface. This is defined to
+ * be compatible with `ITokenManager.hal`.
+ * - `HInterface`: The base type for a hidl interface. Currently, it is defined
+ * as `::android::hidl::base::V1_0::IBase`.
+ * - `HALINTERFACE`: The hidl interface that will be sent through binders.
+ * - `INTERFACE`: The binder interface that will be the wrapper of
+ * `HALINTERFACE`. `INTERFACE` is supposed to be similar to `HALINTERFACE`.
+ *
+ * To demonstrate how this is done, here is an example. Suppose `INTERFACE` is
+ * `IFoo` and `HALINTERFACE` is `HFoo`. The required steps are:
+ * 1. Use DECLARE_HYBRID_META_INTERFACE instead of DECLARE_META_INTERFACE in the
+ * definition of `IFoo`. The usage is
+ * DECLARE_HYBRID_META_INTERFACE(IFoo, HFoo)
+ * inside the body of `IFoo`.
+ * 2. Create a converter class that derives from
+ * `H2BConverter<HFoo, IFoo, BnFoo>`. Let us call this `H2BFoo`.
+ * 3. Add the following constructors in `H2BFoo` that call the corresponding
+ * constructors in `H2BConverter`:
+ * H2BFoo(const sp<HalInterface>& base) : CBase(base) {}
+ * Note: `CBase = H2BConverter<HFoo, IFoo, BnFoo>` and `HalInterface = HFoo`
+ * are member typedefs of `CBase`, so the above line can be copied verbatim
+ * into `H2BFoo`.
+ * 4. Add conversion functions inside `H2BFoo`. `H2BConverter` provides a
+ * protected `mBase` of type `sp<HFoo>` that can be used to access the HFoo
+ * instance. (There is also a public function named `getHalInterface()` that
+ * returns `mBase`.)
+ * 5. Create a hardware proxy class that derives from
+ * `HpInterface<BpFoo, H2BFoo>`. Name this class `HpFoo`. (This name cannot
+ * deviate. See step 8 below.)
+ * 6. Add the following constructor to `HpFoo`:
+ * HpFoo(const sp<IBinder>& base): PBase(base) {}
+ * Note: `PBase` a member typedef of `HpInterface<BpFoo, H2BFoo>` that is
+ * equal to `HpInterface<BpFoo, H2BFoo>` itself, so the above line can be
+ * copied verbatim into `HpFoo`.
+ * 7. Delegate all functions in `HpFoo` that come from `IFoo` except
+ * `getHalToken` and `getHalInterface` to the protected member `mBase`,
+ * which is defined in `HpInterface<BpFoo, H2BFoo>` (hence in `HpFoo`) with
+ * type `IFoo`. (There is also a public function named `getBaseInterface()`
+ * that returns `mBase`.)
+ * 8. Replace the existing `IMPLEMENT_META_INTERFACE` for INTERFACE by
+ * `IMPLEMENT_HYBRID_META_INTERFACE`. Note that this macro relies on the
+ * exact naming of `HpFoo`, where `Foo` comes from the interface name `IFoo`.
+ * An example usage is
+ * IMPLEMENT_HYBRID_META_INTERFACE(IFoo, HFoo, "example.interface.foo");
+ *
+ * `GETTOKEN` Template Argument
+ * ============================
+ *
+ * Following the instructions above, `H2BConverter` and `HpInterface` would use
+ * `transact()` to send over tokens, with `code` (the first argument of
+ * `transact()`) equal to a 4-byte value of '_GTK'. If this value clashes with
+ * other values already in use in the `Bp` class, it can be changed by supplying
+ * the last optional template argument to `H2BConverter` and `HpInterface`.
+ *
+ */
+
+namespace android {
+
+typedef uint64_t HalToken;
+typedef ::android::hidl::base::V1_0::IBase HInterface;
+
+sp<HInterface> retrieveHalInterface(const HalToken& token);
+bool createHalToken(const sp<HInterface>& interface, HalToken* token);
+bool deleteHalToken(const HalToken& token);
+
+template <
+ typename HINTERFACE,
+ typename INTERFACE,
+ typename BNINTERFACE,
+ uint32_t GETTOKEN = '_GTK'>
+class H2BConverter : public BNINTERFACE {
+public:
+ typedef H2BConverter<HINTERFACE, INTERFACE, BNINTERFACE, GETTOKEN> CBase;
+ typedef INTERFACE BaseInterface;
+ typedef HINTERFACE HalInterface;
+ static constexpr uint32_t GET_HAL_TOKEN = GETTOKEN;
+
+ H2BConverter(const sp<HalInterface>& base) : mBase(base) {}
+ virtual status_t onTransact(uint32_t code,
+ const Parcel& data, Parcel* reply, uint32_t flags = 0);
+ sp<HalInterface> getHalInterface() override { return mBase; }
+ HalInterface* getBaseInterface() { return mBase.get(); }
+
+protected:
+ sp<HalInterface> mBase;
+};
+
+template <typename BPINTERFACE, typename CONVERTER, uint32_t GETTOKEN = '_GTK'>
+class HpInterface : public BPINTERFACE {
+public:
+ typedef HpInterface<BPINTERFACE, CONVERTER, GETTOKEN> PBase; // Proxy Base
+ typedef typename CONVERTER::BaseInterface BaseInterface;
+ typedef typename CONVERTER::HalInterface HalInterface;
+ static constexpr uint32_t GET_HAL_TOKEN = GETTOKEN;
+
+ explicit HpInterface(const sp<IBinder>& impl);
+ sp<HalInterface> getHalInterface() override { return mHal; }
+ BaseInterface* getBaseInterface() { return mBase.get(); }
+
+protected:
+ sp<BaseInterface> mBase;
+ sp<HalInterface> mHal;
+};
+
+// ----------------------------------------------------------------------
+
+#define DECLARE_HYBRID_META_INTERFACE(INTERFACE, HAL) \
+ static const ::android::String16 descriptor; \
+ static ::android::sp<I##INTERFACE> asInterface( \
+ const ::android::sp<::android::IBinder>& obj); \
+ virtual const ::android::String16& getInterfaceDescriptor() const; \
+ I##INTERFACE(); \
+ virtual ~I##INTERFACE(); \
+ virtual sp<HAL> getHalInterface(); \
+
+
+#define IMPLEMENT_HYBRID_META_INTERFACE(INTERFACE, HAL, NAME) \
+ const ::android::String16 I##INTERFACE::descriptor(NAME); \
+ const ::android::String16& \
+ I##INTERFACE::getInterfaceDescriptor() const { \
+ return I##INTERFACE::descriptor; \
+ } \
+ ::android::sp<I##INTERFACE> I##INTERFACE::asInterface( \
+ const ::android::sp<::android::IBinder>& obj) \
+ { \
+ ::android::sp<I##INTERFACE> intr; \
+ if (obj != NULL) { \
+ intr = static_cast<I##INTERFACE*>( \
+ obj->queryLocalInterface( \
+ I##INTERFACE::descriptor).get()); \
+ if (intr == NULL) { \
+ intr = new Hp##INTERFACE(obj); \
+ } \
+ } \
+ return intr; \
+ } \
+ I##INTERFACE::I##INTERFACE() { } \
+ I##INTERFACE::~I##INTERFACE() { } \
+ sp<HAL> I##INTERFACE::getHalInterface() { return nullptr; } \
+
+// ----------------------------------------------------------------------
+
+template <
+ typename HINTERFACE,
+ typename INTERFACE,
+ typename BNINTERFACE,
+ uint32_t GETTOKEN>
+status_t H2BConverter<HINTERFACE, INTERFACE, BNINTERFACE, GETTOKEN>::
+ onTransact(
+ uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags) {
+ if (code == GET_HAL_TOKEN) {
+ HalToken token;
+ bool result;
+ result = createHalToken(mBase, &token);
+ if (!result) {
+ ALOGE("H2BConverter: Failed to create HAL token.");
+ }
+ reply->writeBool(result);
+ reply->writeUint64(token);
+ return NO_ERROR;
+ }
+ return BNINTERFACE::onTransact(code, data, reply, flags);
+}
+
+template <typename BPINTERFACE, typename CONVERTER, uint32_t GETTOKEN>
+HpInterface<BPINTERFACE, CONVERTER, GETTOKEN>::HpInterface(
+ const sp<IBinder>& impl):
+ BPINTERFACE(impl),
+ mBase(nullptr) {
+
+ Parcel data, reply;
+ data.writeInterfaceToken(BaseInterface::getInterfaceDescriptor());
+ if (this->remote()->transact(GET_HAL_TOKEN, data, &reply) == NO_ERROR) {
+ bool tokenCreated = reply.readBool();
+ HalToken token = reply.readUint64();
+ if (!tokenCreated) {
+ ALOGE("HpInterface: Sender failed to create HAL token.");
+ mBase = this;
+ } else {
+ sp<HInterface> hInterface = retrieveHalInterface(token);
+ deleteHalToken(token);
+ if (hInterface != nullptr) {
+ mHal = static_cast<HalInterface*>(hInterface.get());
+ mBase = new CONVERTER(mHal);
+ } else {
+ ALOGE("HpInterface: Cannot retrieve HAL interface from token.");
+ mBase = this;
+ }
+ }
+ } else {
+ mBase = this;
+ }
+}
+
+// ----------------------------------------------------------------------
+
+}; // namespace android
+
+#endif // ANDROID_HALTOKEN_H
diff --git a/libs/binder/Android.bp b/libs/binder/Android.bp
index 93b8684..2cb44eb 100644
--- a/libs/binder/Android.bp
+++ b/libs/binder/Android.bp
@@ -34,6 +34,7 @@
"IResultReceiver.cpp",
"IServiceManager.cpp",
"IShellCallback.cpp",
+ "HalToken.cpp",
"MemoryBase.cpp",
"MemoryDealer.cpp",
"MemoryHeapBase.cpp",
@@ -65,6 +66,8 @@
"liblog",
"libcutils",
"libutils",
+ "libhidlbase",
+ "android.hidl.token@1.0",
],
export_shared_lib_headers: [
"libbase",
diff --git a/libs/binder/HalToken.cpp b/libs/binder/HalToken.cpp
new file mode 100644
index 0000000..6e71a52
--- /dev/null
+++ b/libs/binder/HalToken.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2005 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 "HalToken"
+
+#include <utils/Log.h>
+#include <binder/HalToken.h>
+
+#include <android/hidl/token/1.0/ITokenManager.h>
+
+namespace android {
+
+using ::android::hidl::token::V1_0::ITokenManager;
+
+sp<ITokenManager> gTokenManager = nullptr;
+
+ITokenManager* getTokenManager() {
+ if (gTokenManager != nullptr) {
+ return gTokenManager.get();
+ }
+ gTokenManager = ITokenManager::getService();
+ if (gTokenManager == nullptr) {
+ ALOGE("Cannot retrieve TokenManager.");
+ }
+ return gTokenManager.get();
+}
+
+sp<HInterface> retrieveHalInterface(const HalToken& token) {
+ auto transaction = getTokenManager()->get(token);
+ if (!transaction.isOk()) {
+ ALOGE("getHalInterface: Cannot obtain interface from token.");
+ return nullptr;
+ }
+ return static_cast<sp<HInterface> >(transaction);
+}
+
+bool createHalToken(const sp<HInterface>& interface, HalToken* token) {
+ auto transaction = getTokenManager()->createToken(interface);
+ if (!transaction.isOk()) {
+ ALOGE("createHalToken: Cannot create token from interface.");
+ return false;
+ }
+ *token = static_cast<HalToken>(transaction);
+ return true;
+}
+
+bool deleteHalToken(const HalToken& token) {
+ auto transaction = getTokenManager()->unregister(token);
+ if (!transaction.isOk()) {
+ ALOGE("deleteHalToken: Cannot unregister hal token.");
+ return false;
+ }
+ return true;
+}
+
+}; // namespace android
+