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/*
* 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
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