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/*
* Copyright (C) 2019 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 "AidlLazyServiceRegistrar"
#include <binder/LazyServiceRegistrar.h>
#include <binder/IPCThreadState.h>
#include <binder/IServiceManager.h>
#include <android/os/BnClientCallback.h>
#include <android/os/IServiceManager.h>
#include <utils/Log.h>
namespace android {
namespace binder {
namespace internal {
using AidlServiceManager = android::os::IServiceManager;
class ClientCounterCallback : public ::android::os::BnClientCallback {
public:
ClientCounterCallback() : mNumConnectedServices(0) {}
bool registerService(const sp<IBinder>& service, const std::string& name,
bool allowIsolated, int dumpFlags);
protected:
Status onClients(const sp<IBinder>& service, bool clients) override;
private:
/**
* Unregisters all services that we can. If we can't unregister all, re-register other
* services.
*/
void tryShutdown();
/**
* Counter of the number of services that currently have at least one client.
*/
size_t mNumConnectedServices;
struct Service {
sp<IBinder> service;
bool allowIsolated;
int dumpFlags;
};
/**
* Map of registered names and services
*/
std::map<std::string, Service> mRegisteredServices;
};
bool ClientCounterCallback::registerService(const sp<IBinder>& service, const std::string& name,
bool allowIsolated, int dumpFlags) {
auto manager = interface_cast<AidlServiceManager>(
ProcessState::self()->getContextObject(nullptr));
bool reRegister = mRegisteredServices.count(name) > 0;
std::string regStr = (reRegister) ? "Re-registering" : "Registering";
ALOGI("%s service %s", regStr.c_str(), name.c_str());
if (!manager->addService(name.c_str(), service, allowIsolated, dumpFlags).isOk()) {
ALOGE("Failed to register service %s", name.c_str());
return false;
}
if (!manager->registerClientCallback(name, service, this).isOk()) {
ALOGE("Failed to add client callback for service %s", name.c_str());
return false;
}
if (!reRegister) {
// Only add this when a service is added for the first time, as it is not removed
mRegisteredServices[name] = {service, allowIsolated, dumpFlags};
}
return true;
}
/**
* onClients is oneway, so no need to worry about multi-threading. Note that this means multiple
* invocations could occur on different threads however.
*/
Status ClientCounterCallback::onClients(const sp<IBinder>& service, bool clients) {
if (clients) {
mNumConnectedServices++;
} else {
mNumConnectedServices--;
}
ALOGI("Process has %zu (of %zu available) client(s) in use after notification %s has clients: %d",
mNumConnectedServices, mRegisteredServices.size(),
String8(service->getInterfaceDescriptor()).string(), clients);
if (mNumConnectedServices == 0) {
tryShutdown();
}
return Status::ok();
}
void ClientCounterCallback::tryShutdown() {
ALOGI("Trying to shut down the service. No clients in use for any service in process.");
// This makes the same assumption as IServiceManager.cpp. Could dedupe if used in more places.
auto manager = interface_cast<AidlServiceManager>(
ProcessState::self()->getContextObject(nullptr));
auto unRegisterIt = mRegisteredServices.begin();
for (; unRegisterIt != mRegisteredServices.end(); ++unRegisterIt) {
auto& entry = (*unRegisterIt);
bool success = manager->tryUnregisterService(entry.first, entry.second.service).isOk();
if (!success) {
ALOGI("Failed to unregister service %s", entry.first.c_str());
break;
}
}
if (unRegisterIt == mRegisteredServices.end()) {
ALOGI("Unregistered all clients and exiting");
exit(EXIT_SUCCESS);
}
for (auto reRegisterIt = mRegisteredServices.begin(); reRegisterIt != unRegisterIt;
reRegisterIt++) {
auto& entry = (*reRegisterIt);
// re-register entry
if (!registerService(entry.second.service, entry.first, entry.second.allowIsolated,
entry.second.dumpFlags)) {
// Must restart. Otherwise, clients will never be able to get a hold of this service.
ALOGE("Bad state: could not re-register services");
}
}
}
} // namespace internal
LazyServiceRegistrar::LazyServiceRegistrar() {
mClientCC = std::make_shared<internal::ClientCounterCallback>();
}
LazyServiceRegistrar& LazyServiceRegistrar::getInstance() {
static auto registrarInstance = new LazyServiceRegistrar();
return *registrarInstance;
}
status_t LazyServiceRegistrar::registerService(const sp<IBinder>& service, const std::string& name,
bool allowIsolated, int dumpFlags) {
if (!mClientCC->registerService(service, name, allowIsolated, dumpFlags)) {
return UNKNOWN_ERROR;
}
return OK;
}
} // namespace hardware
} // namespace android
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