libaudiohal: Dynamically load appropriate HIDL shim library
Remove static linking to libaudiohal@N.0.so libraries.
Instead, use HIDL IServiceManager to figure out the actual
version used by the device and load the appropriate library
dynamically.
Bug: 142480271
Bug: 148118201
Test: make and check audio on the device
Change-Id: I8e6eb9eeef3335da516d983d5d4f0f1b128ef0a6
diff --git a/media/libaudiohal/FactoryHalHidl.cpp b/media/libaudiohal/FactoryHalHidl.cpp
new file mode 100644
index 0000000..5985ef0
--- /dev/null
+++ b/media/libaudiohal/FactoryHalHidl.cpp
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2020 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 "FactoryHalHidl"
+
+#include <media/audiohal/FactoryHalHidl.h>
+
+#include <dlfcn.h>
+
+#include <android/hidl/manager/1.0/IServiceManager.h>
+#include <hidl/ServiceManagement.h>
+#include <hidl/Status.h>
+#include <utils/Log.h>
+
+namespace android::detail {
+
+namespace {
+/** Supported HAL versions, in order of preference.
+ */
+const char* sAudioHALVersions[] = {
+ "6.0",
+ "5.0",
+ "4.0",
+ "2.0",
+ nullptr
+};
+
+bool createHalService(const std::string& version, const std::string& interface,
+ void** rawInterface) {
+ const std::string libName = "libaudiohal@" + version + ".so";
+ const std::string factoryFunctionName = "create" + interface;
+ constexpr int dlMode = RTLD_LAZY;
+ void* handle = nullptr;
+ dlerror(); // clear
+ handle = dlopen(libName.c_str(), dlMode);
+ if (handle == nullptr) {
+ const char* error = dlerror();
+ ALOGE("Failed to dlopen %s: %s", libName.c_str(),
+ error != nullptr ? error : "unknown error");
+ return false;
+ }
+ void* (*factoryFunction)();
+ *(void **)(&factoryFunction) = dlsym(handle, factoryFunctionName.c_str());
+ if (!factoryFunction) {
+ const char* error = dlerror();
+ ALOGE("Factory function %s not found in library %s: %s",
+ factoryFunctionName.c_str(), libName.c_str(),
+ error != nullptr ? error : "unknown error");
+ dlclose(handle);
+ return false;
+ }
+ *rawInterface = (*factoryFunction)();
+ ALOGW_IF(!*rawInterface, "Factory function %s from %s returned nullptr",
+ factoryFunctionName.c_str(), libName.c_str());
+ return true;
+}
+
+bool hasHalService(const std::string& package, const std::string& version,
+ const std::string& interface) {
+ using ::android::hidl::manager::V1_0::IServiceManager;
+ sp<IServiceManager> sm = ::android::hardware::defaultServiceManager();
+ if (!sm) {
+ ALOGE("Failed to obtain HIDL ServiceManager");
+ return false;
+ }
+ // Since audio HAL doesn't support multiple clients, avoid instantiating
+ // the interface right away. Instead, query the transport type for it.
+ using ::android::hardware::Return;
+ using Transport = IServiceManager::Transport;
+ const std::string fqName = package + "@" + version + "::" + interface;
+ const std::string instance = "default";
+ Return<Transport> transport = sm->getTransport(fqName, instance);
+ if (!transport.isOk()) {
+ ALOGE("Failed to obtain transport type for %s/%s: %s",
+ fqName.c_str(), instance.c_str(), transport.description().c_str());
+ return false;
+ }
+ return transport != Transport::EMPTY;
+}
+
+} // namespace
+
+void* createPreferredImpl(const std::string& package, const std::string& interface) {
+ for (auto version = detail::sAudioHALVersions; version != nullptr; ++version) {
+ void* rawInterface = nullptr;
+ if (hasHalService(package, *version, interface)
+ && createHalService(*version, interface, &rawInterface)) {
+ return rawInterface;
+ }
+ }
+ return nullptr;
+}
+
+} // namespace android::detail