transport/ServiceManagement.cpp - platform/system/libhidl - Git at Google

 /*
  * Copyright (C) 2016 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 "ServiceManagement"

 #include <android/dlext.h>
 #include <condition_variable>
 #include <dlfcn.h>
 #include <dirent.h>
 #include <fstream>
 #include <pthread.h>
 #include <unistd.h>

 #include <mutex>
 #include <regex>
 #include <set>

 #include <hidl/HidlBinderSupport.h>
 #include <hidl/ServiceManagement.h>
 #include <hidl/Status.h>

 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <hwbinder/IPCThreadState.h>
 #include <hwbinder/Parcel.h>
 #include <vndksupport/linker.h>

 #include <android/hidl/manager/1.1/IServiceManager.h>
 #include <android/hidl/manager/1.1/BpHwServiceManager.h>
 #include <android/hidl/manager/1.1/BnHwServiceManager.h>

 #define RE_COMPONENT    "[a-zA-Z_][a-zA-Z_0-9]*"
 #define RE_PATH         RE_COMPONENT "(?:[.]" RE_COMPONENT ")*"
 static const std::regex gLibraryFileNamePattern("(" RE_PATH "@[0-9]+[.][0-9]+)-impl(.*?).so");

 using android::base::WaitForProperty;

 using IServiceManager1_0 = android::hidl::manager::V1_0::IServiceManager;
 using IServiceManager1_1 = android::hidl::manager::V1_1::IServiceManager;
 using android::hidl::manager::V1_0::IServiceNotification;
 using android::hidl::manager::V1_1::BpHwServiceManager;
 using android::hidl::manager::V1_1::BnHwServiceManager;

 namespace android {
 namespace hardware {

 namespace details {
 extern Mutex gDefaultServiceManagerLock;
 extern sp<android::hidl::manager::V1_1::IServiceManager> gDefaultServiceManager;
 }  // namespace details

 static const char* kHwServicemanagerReadyProperty = "hwservicemanager.ready";

 void waitForHwServiceManager() {
     using std::literals::chrono_literals::operator""s;

     while (!WaitForProperty(kHwServicemanagerReadyProperty, "true", 1s)) {
         LOG(WARNING) << "Waited for hwservicemanager.ready for a second, waiting another...";
     }
 }

 bool endsWith(const std::string &in, const std::string &suffix) {
     return in.size() >= suffix.size() &&
            in.substr(in.size() - suffix.size()) == suffix;
 }

 bool startsWith(const std::string &in, const std::string &prefix) {
     return in.size() >= prefix.size() &&
            in.substr(0, prefix.size()) == prefix;
 }

 std::string binaryName() {
     std::ifstream ifs("/proc/self/cmdline");
     std::string cmdline;
     if (!ifs.is_open()) {
         return "";
     }
     ifs >> cmdline;

     size_t idx = cmdline.rfind("/");
     if (idx != std::string::npos) {
         cmdline = cmdline.substr(idx + 1);
     }

     return cmdline;
 }

 void tryShortenProcessName(const std::string &packageName) {
     std::string processName = binaryName();

     if (!startsWith(processName, packageName)) {
         return;
     }

     // e.x. android.hardware.module.foo@1.0 -> foo@1.0
     size_t lastDot = packageName.rfind('.');
     size_t secondDot = packageName.rfind('.', lastDot - 1);

     if (secondDot == std::string::npos) {
         return;
     }

     std::string newName = processName.substr(secondDot + 1,
             16 /* TASK_COMM_LEN */ - 1);
     ALOGI("Removing namespace from process name %s to %s.",
             processName.c_str(), newName.c_str());

     int rc = pthread_setname_np(pthread_self(), newName.c_str());
     ALOGI_IF(rc != 0, "Removing namespace from process name %s failed.",
             processName.c_str());
 }

 namespace details {

 void onRegistration(const std::string &packageName,
                     const std::string& /* interfaceName */,
                     const std::string& /* instanceName */) {
     tryShortenProcessName(packageName);
 }

 }  // details

 sp<IServiceManager1_0> defaultServiceManager() {
     return defaultServiceManager1_1();
 }
 sp<IServiceManager1_1> defaultServiceManager1_1() {
     {
         AutoMutex _l(details::gDefaultServiceManagerLock);
         if (details::gDefaultServiceManager != NULL) {
             return details::gDefaultServiceManager;
         }

         if (access("/dev/hwbinder", F_OK|R_OK|W_OK) != 0) {
             // HwBinder not available on this device or not accessible to
             // this process.
             return nullptr;
         }

         waitForHwServiceManager();

         while (details::gDefaultServiceManager == NULL) {
             details::gDefaultServiceManager =
                     fromBinder<IServiceManager1_1, BpHwServiceManager, BnHwServiceManager>(
                         ProcessState::self()->getContextObject(NULL));
             if (details::gDefaultServiceManager == NULL) {
                 LOG(ERROR) << "Waited for hwservicemanager, but got nullptr.";
                 sleep(1);
             }
         }
     }

     return details::gDefaultServiceManager;
 }

 std::vector<std::string> search(const std::string &path,
                               const std::string &prefix,
                               const std::string &suffix) {
     std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(path.c_str()), closedir);
     if (!dir) return {};

     std::vector<std::string> results{};

     dirent* dp;
     while ((dp = readdir(dir.get())) != nullptr) {
         std::string name = dp->d_name;

         if (startsWith(name, prefix) &&
                 endsWith(name, suffix)) {
             results.push_back(name);
         }
     }

     return results;
 }

 bool matchPackageName(const std::string& lib, std::string* matchedName, std::string* implName) {
     std::smatch match;
     if (std::regex_match(lib, match, gLibraryFileNamePattern)) {
         *matchedName = match.str(1) + "::I*";
         *implName = match.str(2);
         return true;
     }
     return false;
 }

 static void registerReference(const hidl_string &interfaceName, const hidl_string &instanceName) {
     sp<IServiceManager1_0> binderizedManager = defaultServiceManager();
     if (binderizedManager == nullptr) {
         LOG(WARNING) << "Could not registerReference for "
                      << interfaceName << "/" << instanceName
                      << ": null binderized manager.";
         return;
     }
     auto ret = binderizedManager->registerPassthroughClient(interfaceName, instanceName);
     if (!ret.isOk()) {
         LOG(WARNING) << "Could not registerReference for "
                      << interfaceName << "/" << instanceName
                      << ": " << ret.description();
         return;
     }
     LOG(VERBOSE) << "Successfully registerReference for "
                  << interfaceName << "/" << instanceName;
 }

 using InstanceDebugInfo = hidl::manager::V1_0::IServiceManager::InstanceDebugInfo;
 static inline void fetchPidsForPassthroughLibraries(
     std::map<std::string, InstanceDebugInfo>* infos) {
     static const std::string proc = "/proc/";

     std::map<std::string, std::set<pid_t>> pids;
     std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(proc.c_str()), closedir);
     if (!dir) return;
     dirent* dp;
     while ((dp = readdir(dir.get())) != nullptr) {
         pid_t pid = strtoll(dp->d_name, NULL, 0);
         if (pid == 0) continue;
         std::string mapsPath = proc + dp->d_name + "/maps";
         std::ifstream ifs{mapsPath};
         if (!ifs.is_open()) continue;

         for (std::string line; std::getline(ifs, line);) {
             // The last token of line should look like
             // vendor/lib64/hw/android.hardware.foo@1.0-impl-extra.so
             // Use some simple filters to ignore bad lines before extracting libFileName
             // and checking the key in info to make parsing faster.
             if (line.back() != 'o') continue;
             if (line.rfind('@') == std::string::npos) continue;

             auto spacePos = line.rfind(' ');
             if (spacePos == std::string::npos) continue;
             auto libFileName = line.substr(spacePos + 1);
             auto it = infos->find(libFileName);
             if (it == infos->end()) continue;
             pids[libFileName].insert(pid);
         }
     }
     for (auto& pair : *infos) {
         pair.second.clientPids =
             std::vector<pid_t>{pids[pair.first].begin(), pids[pair.first].end()};
     }
 }

 struct PassthroughServiceManager : IServiceManager1_1 {
     static void openLibs(const std::string& fqName,
             std::function<bool /* continue */(void* /* handle */,
                 const std::string& /* lib */, const std::string& /* sym */)> eachLib) {
         //fqName looks like android.hardware.foo@1.0::IFoo
         size_t idx = fqName.find("::");

         if (idx == std::string::npos ||
                 idx + strlen("::") + 1 >= fqName.size()) {
             LOG(ERROR) << "Invalid interface name passthrough lookup: " << fqName;
             return;
         }

         std::string packageAndVersion = fqName.substr(0, idx);
         std::string ifaceName = fqName.substr(idx + strlen("::"));

         const std::string prefix = packageAndVersion + "-impl";
         const std::string sym = "HIDL_FETCH_" + ifaceName;

         const int dlMode = RTLD_LAZY;
         void *handle = nullptr;

         dlerror(); // clear

         std::vector<std::string> paths = {HAL_LIBRARY_PATH_ODM, HAL_LIBRARY_PATH_VENDOR,
                                           HAL_LIBRARY_PATH_VNDK_SP, HAL_LIBRARY_PATH_SYSTEM};
 #ifdef LIBHIDL_TARGET_DEBUGGABLE
         const char* env = std::getenv("TREBLE_TESTING_OVERRIDE");
         const bool trebleTestingOverride = env && !strcmp(env, "true");
         if (trebleTestingOverride) {
             const char* vtsRootPath = std::getenv("VTS_ROOT_PATH");
             if (vtsRootPath && strlen(vtsRootPath) > 0) {
                 const std::string halLibraryPathVtsOverride =
                     std::string(vtsRootPath) + HAL_LIBRARY_PATH_SYSTEM;
                 paths.push_back(halLibraryPathVtsOverride);
             }
         }
 #endif
         for (const std::string& path : paths) {
             std::vector<std::string> libs = search(path, prefix, ".so");

             for (const std::string &lib : libs) {
                 const std::string fullPath = path + lib;

                 if (path != HAL_LIBRARY_PATH_SYSTEM) {
                     handle = android_load_sphal_library(fullPath.c_str(), dlMode);
                 } else {
                     handle = dlopen(fullPath.c_str(), dlMode);
                 }

                 if (handle == nullptr) {
                     const char* error = dlerror();
                     LOG(ERROR) << "Failed to dlopen " << lib << ": "
                                << (error == nullptr ? "unknown error" : error);
                     continue;
                 }

                 if (!eachLib(handle, lib, sym)) {
                     return;
                 }
             }
         }
     }

     Return<sp<IBase>> get(const hidl_string& fqName,
                           const hidl_string& name) override {
         sp<IBase> ret = nullptr;

         openLibs(fqName, [&](void* handle, const std::string &lib, const std::string &sym) {
             IBase* (*generator)(const char* name);
             *(void **)(&generator) = dlsym(handle, sym.c_str());
             if(!generator) {
                 const char* error = dlerror();
                 LOG(ERROR) << "Passthrough lookup opened " << lib
                            << " but could not find symbol " << sym << ": "
                            << (error == nullptr ? "unknown error" : error);
                 dlclose(handle);
                 return true;
             }

             ret = (*generator)(name.c_str());

             if (ret == nullptr) {
                 dlclose(handle);
                 return true; // this module doesn't provide this instance name
             }

             registerReference(fqName, name);
             return false;
         });

         return ret;
     }

     Return<bool> add(const hidl_string& /* name */,
                      const sp<IBase>& /* service */) override {
         LOG(FATAL) << "Cannot register services with passthrough service manager.";
         return false;
     }

     Return<Transport> getTransport(const hidl_string& /* fqName */,
                                    const hidl_string& /* name */) {
         LOG(FATAL) << "Cannot getTransport with passthrough service manager.";
         return Transport::EMPTY;
     }

     Return<void> list(list_cb /* _hidl_cb */) override {
         LOG(FATAL) << "Cannot list services with passthrough service manager.";
         return Void();
     }
     Return<void> listByInterface(const hidl_string& /* fqInstanceName */,
                                  listByInterface_cb /* _hidl_cb */) override {
         // TODO: add this functionality
         LOG(FATAL) << "Cannot list services with passthrough service manager.";
         return Void();
     }

     Return<bool> registerForNotifications(const hidl_string& /* fqName */,
                                           const hidl_string& /* name */,
                                           const sp<IServiceNotification>& /* callback */) override {
         // This makes no sense.
         LOG(FATAL) << "Cannot register for notifications with passthrough service manager.";
         return false;
     }

     Return<void> debugDump(debugDump_cb _hidl_cb) override {
         using Arch = ::android::hidl::base::V1_0::DebugInfo::Architecture;
         using std::literals::string_literals::operator""s;
         static std::vector<std::pair<Arch, std::vector<const char*>>> sAllPaths{
             {Arch::IS_64BIT,
              {HAL_LIBRARY_PATH_ODM_64BIT, HAL_LIBRARY_PATH_VENDOR_64BIT,
               HAL_LIBRARY_PATH_VNDK_SP_64BIT, HAL_LIBRARY_PATH_SYSTEM_64BIT}},
             {Arch::IS_32BIT,
              {HAL_LIBRARY_PATH_ODM_32BIT, HAL_LIBRARY_PATH_VENDOR_32BIT,
               HAL_LIBRARY_PATH_VNDK_SP_32BIT, HAL_LIBRARY_PATH_SYSTEM_32BIT}}};
         std::map<std::string, InstanceDebugInfo> map;
         for (const auto &pair : sAllPaths) {
             Arch arch = pair.first;
             for (const auto &path : pair.second) {
                 std::vector<std::string> libs = search(path, "", ".so");
                 for (const std::string &lib : libs) {
                     std::string matchedName;
                     std::string implName;
                     if (matchPackageName(lib, &matchedName, &implName)) {
                         std::string instanceName{"* ("s + path + ")"s};
                         if (!implName.empty()) instanceName += " ("s + implName + ")"s;
                         map.emplace(path + lib, InstanceDebugInfo{.interfaceName = matchedName,
                                                                   .instanceName = instanceName,
                                                                   .clientPids = {},
                                                                   .arch = arch});
                     }
                 }
             }
         }
         fetchPidsForPassthroughLibraries(&map);
         hidl_vec<InstanceDebugInfo> vec;
         vec.resize(map.size());
         size_t idx = 0;
         for (auto&& pair : map) {
             vec[idx++] = std::move(pair.second);
         }
         _hidl_cb(vec);
         return Void();
     }

     Return<void> registerPassthroughClient(const hidl_string &, const hidl_string &) override {
         // This makes no sense.
         LOG(FATAL) << "Cannot call registerPassthroughClient on passthrough service manager. "
                    << "Call it on defaultServiceManager() instead.";
         return Void();
     }

     Return<bool> unregisterForNotifications(const hidl_string& /* fqName */,
                                             const hidl_string& /* name */,
                                             const sp<IServiceNotification>& /* callback */) override {
         // This makes no sense.
         LOG(FATAL) << "Cannot unregister for notifications with passthrough service manager.";
         return false;
     }

 };

 sp<IServiceManager1_0> getPassthroughServiceManager() {
     return getPassthroughServiceManager1_1();
 }
 sp<IServiceManager1_1> getPassthroughServiceManager1_1() {
     static sp<PassthroughServiceManager> manager(new PassthroughServiceManager());
     return manager;
 }

 namespace details {

 void preloadPassthroughService(const std::string &descriptor) {
     PassthroughServiceManager::openLibs(descriptor,
         [&](void* /* handle */, const std::string& /* lib */, const std::string& /* sym */) {
             // do nothing
             return true; // open all libs
         });
 }

 struct Waiter : IServiceNotification {
     Return<void> onRegistration(const hidl_string& /* fqName */,
                                 const hidl_string& /* name */,
                                 bool /* preexisting */) override {
         std::unique_lock<std::mutex> lock(mMutex);
         if (mRegistered) {
             return Void();
         }
         mRegistered = true;
         lock.unlock();

         mCondition.notify_one();
         return Void();
     }

     void wait(const std::string &interface, const std::string &instanceName) {
         using std::literals::chrono_literals::operator""s;

         std::unique_lock<std::mutex> lock(mMutex);
         while(true) {
             mCondition.wait_for(lock, 1s, [this]{
                 return mRegistered;
             });

             if (mRegistered) {
                 break;
             }

             LOG(WARNING) << "Waited one second for "
                          << interface << "/" << instanceName
                          << ". Waiting another...";
         }
     }

 private:
     std::mutex mMutex;
     std::condition_variable mCondition;
     bool mRegistered = false;
 };

 void waitForHwService(
         const std::string &interface, const std::string &instanceName) {
     const sp<IServiceManager1_1> manager = defaultServiceManager1_1();

     if (manager == nullptr) {
         LOG(ERROR) << "Could not get default service manager.";
         return;
     }

     sp<Waiter> waiter = new Waiter();
     Return<bool> ret = manager->registerForNotifications(interface, instanceName, waiter);

     if (!ret.isOk()) {
         LOG(ERROR) << "Transport error, " << ret.description()
             << ", during notification registration for "
             << interface << "/" << instanceName << ".";
         return;
     }

     if (!ret) {
         LOG(ERROR) << "Could not register for notifications for "
             << interface << "/" << instanceName << ".";
         return;
     }

     waiter->wait(interface, instanceName);

     if (!manager->unregisterForNotifications(interface, instanceName, waiter).withDefault(false)) {
         LOG(ERROR) << "Could not unregister service notification for "
             << interface << "/" << instanceName << ".";
     }
 }

 }; // namespace details

 }; // namespace hardware
 }; // namespace android
	/*
	* Copyright (C) 2016 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 "ServiceManagement"

	#include <android/dlext.h>
	#include <condition_variable>
	#include <dlfcn.h>
	#include <dirent.h>
	#include <fstream>
	#include <pthread.h>
	#include <unistd.h>

	#include <mutex>
	#include <regex>
	#include <set>

	#include <hidl/HidlBinderSupport.h>
	#include <hidl/ServiceManagement.h>
	#include <hidl/Status.h>

	#include <android-base/logging.h>
	#include <android-base/properties.h>
	#include <hwbinder/IPCThreadState.h>
	#include <hwbinder/Parcel.h>
	#include <vndksupport/linker.h>

	#include <android/hidl/manager/1.1/IServiceManager.h>
	#include <android/hidl/manager/1.1/BpHwServiceManager.h>
	#include <android/hidl/manager/1.1/BnHwServiceManager.h>

	#define RE_COMPONENT "[a-zA-Z_][a-zA-Z_0-9]*"
	#define RE_PATH RE_COMPONENT "(?:[.]" RE_COMPONENT ")*"
	static const std::regex gLibraryFileNamePattern("(" RE_PATH "@[0-9]+[.][0-9]+)-impl(.*?).so");

	using android::base::WaitForProperty;

	using IServiceManager1_0 = android::hidl::manager::V1_0::IServiceManager;
	using IServiceManager1_1 = android::hidl::manager::V1_1::IServiceManager;
	using android::hidl::manager::V1_0::IServiceNotification;
	using android::hidl::manager::V1_1::BpHwServiceManager;
	using android::hidl::manager::V1_1::BnHwServiceManager;

	namespace android {
	namespace hardware {

	namespace details {
	extern Mutex gDefaultServiceManagerLock;
	extern sp<android::hidl::manager::V1_1::IServiceManager> gDefaultServiceManager;
	} // namespace details

	static const char* kHwServicemanagerReadyProperty = "hwservicemanager.ready";

	void waitForHwServiceManager() {
	using std::literals::chrono_literals::operator""s;

	while (!WaitForProperty(kHwServicemanagerReadyProperty, "true", 1s)) {
	LOG(WARNING) << "Waited for hwservicemanager.ready for a second, waiting another...";
	}
	}

	bool endsWith(const std::string &in, const std::string &suffix) {
	return in.size() >= suffix.size() &&
	in.substr(in.size() - suffix.size()) == suffix;
	}

	bool startsWith(const std::string &in, const std::string &prefix) {
	return in.size() >= prefix.size() &&
	in.substr(0, prefix.size()) == prefix;
	}

	std::string binaryName() {
	std::ifstream ifs("/proc/self/cmdline");
	std::string cmdline;
	if (!ifs.is_open()) {
	return "";
	}
	ifs >> cmdline;

	size_t idx = cmdline.rfind("/");
	if (idx != std::string::npos) {
	cmdline = cmdline.substr(idx + 1);
	}

	return cmdline;
	}

	void tryShortenProcessName(const std::string &packageName) {
	std::string processName = binaryName();

	if (!startsWith(processName, packageName)) {
	return;
	}

	// e.x. android.hardware.module.foo@1.0 -> foo@1.0
	size_t lastDot = packageName.rfind('.');
	size_t secondDot = packageName.rfind('.', lastDot - 1);

	if (secondDot == std::string::npos) {
	return;
	}

	std::string newName = processName.substr(secondDot + 1,
	16 /* TASK_COMM_LEN */ - 1);
	ALOGI("Removing namespace from process name %s to %s.",
	processName.c_str(), newName.c_str());

	int rc = pthread_setname_np(pthread_self(), newName.c_str());
	ALOGI_IF(rc != 0, "Removing namespace from process name %s failed.",
	processName.c_str());
	}

	namespace details {

	void onRegistration(const std::string &packageName,
	const std::string& /* interfaceName */,
	const std::string& /* instanceName */) {
	tryShortenProcessName(packageName);
	}

	} // details

	sp<IServiceManager1_0> defaultServiceManager() {
	return defaultServiceManager1_1();
	}
	sp<IServiceManager1_1> defaultServiceManager1_1() {
	{
	AutoMutex _l(details::gDefaultServiceManagerLock);
	if (details::gDefaultServiceManager != NULL) {
	return details::gDefaultServiceManager;
	}

	if (access("/dev/hwbinder", F_OK\|R_OK\|W_OK) != 0) {
	// HwBinder not available on this device or not accessible to
	// this process.
	return nullptr;
	}

	waitForHwServiceManager();

	while (details::gDefaultServiceManager == NULL) {
	details::gDefaultServiceManager =
	fromBinder<IServiceManager1_1, BpHwServiceManager, BnHwServiceManager>(
	ProcessState::self()->getContextObject(NULL));
	if (details::gDefaultServiceManager == NULL) {
	LOG(ERROR) << "Waited for hwservicemanager, but got nullptr.";
	sleep(1);
	}
	}
	}

	return details::gDefaultServiceManager;
	}

	std::vector<std::string> search(const std::string &path,
	const std::string &prefix,
	const std::string &suffix) {
	std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(path.c_str()), closedir);
	if (!dir) return {};

	std::vector<std::string> results{};

	dirent* dp;
	while ((dp = readdir(dir.get())) != nullptr) {
	std::string name = dp->d_name;

	if (startsWith(name, prefix) &&
	endsWith(name, suffix)) {
	results.push_back(name);
	}
	}

	return results;
	}

	bool matchPackageName(const std::string& lib, std::string* matchedName, std::string* implName) {
	std::smatch match;
	if (std::regex_match(lib, match, gLibraryFileNamePattern)) {
	matchedName = match.str(1) + "::I";
	*implName = match.str(2);
	return true;
	}
	return false;
	}

	static void registerReference(const hidl_string &interfaceName, const hidl_string &instanceName) {
	sp<IServiceManager1_0> binderizedManager = defaultServiceManager();
	if (binderizedManager == nullptr) {
	LOG(WARNING) << "Could not registerReference for "
	<< interfaceName << "/" << instanceName
	<< ": null binderized manager.";
	return;
	}
	auto ret = binderizedManager->registerPassthroughClient(interfaceName, instanceName);
	if (!ret.isOk()) {
	LOG(WARNING) << "Could not registerReference for "
	<< interfaceName << "/" << instanceName
	<< ": " << ret.description();
	return;
	}
	LOG(VERBOSE) << "Successfully registerReference for "
	<< interfaceName << "/" << instanceName;
	}

	using InstanceDebugInfo = hidl::manager::V1_0::IServiceManager::InstanceDebugInfo;
	static inline void fetchPidsForPassthroughLibraries(
	std::map<std::string, InstanceDebugInfo>* infos) {
	static const std::string proc = "/proc/";

	std::map<std::string, std::set<pid_t>> pids;
	std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(proc.c_str()), closedir);
	if (!dir) return;
	dirent* dp;
	while ((dp = readdir(dir.get())) != nullptr) {
	pid_t pid = strtoll(dp->d_name, NULL, 0);
	if (pid == 0) continue;
	std::string mapsPath = proc + dp->d_name + "/maps";
	std::ifstream ifs{mapsPath};
	if (!ifs.is_open()) continue;

	for (std::string line; std::getline(ifs, line);) {
	// The last token of line should look like
	// vendor/lib64/hw/android.hardware.foo@1.0-impl-extra.so
	// Use some simple filters to ignore bad lines before extracting libFileName
	// and checking the key in info to make parsing faster.
	if (line.back() != 'o') continue;
	if (line.rfind('@') == std::string::npos) continue;

	auto spacePos = line.rfind(' ');
	if (spacePos == std::string::npos) continue;
	auto libFileName = line.substr(spacePos + 1);
	auto it = infos->find(libFileName);
	if (it == infos->end()) continue;
	pids[libFileName].insert(pid);
	}
	}
	for (auto& pair : *infos) {
	pair.second.clientPids =
	std::vector<pid_t>{pids[pair.first].begin(), pids[pair.first].end()};
	}
	}

	struct PassthroughServiceManager : IServiceManager1_1 {
	static void openLibs(const std::string& fqName,
	std::function<bool /* continue /(void /* handle */,
	const std::string& /* lib /, const std::string& / sym */)> eachLib) {
	//fqName looks like android.hardware.foo@1.0::IFoo
	size_t idx = fqName.find("::");

	if (idx == std::string::npos \|\|
	idx + strlen("::") + 1 >= fqName.size()) {
	LOG(ERROR) << "Invalid interface name passthrough lookup: " << fqName;
	return;
	}

	std::string packageAndVersion = fqName.substr(0, idx);
	std::string ifaceName = fqName.substr(idx + strlen("::"));

	const std::string prefix = packageAndVersion + "-impl";
	const std::string sym = "HIDL_FETCH_" + ifaceName;

	const int dlMode = RTLD_LAZY;
	void *handle = nullptr;

	dlerror(); // clear

	std::vector<std::string> paths = {HAL_LIBRARY_PATH_ODM, HAL_LIBRARY_PATH_VENDOR,
	HAL_LIBRARY_PATH_VNDK_SP, HAL_LIBRARY_PATH_SYSTEM};
	#ifdef LIBHIDL_TARGET_DEBUGGABLE
	const char* env = std::getenv("TREBLE_TESTING_OVERRIDE");
	const bool trebleTestingOverride = env && !strcmp(env, "true");
	if (trebleTestingOverride) {
	const char* vtsRootPath = std::getenv("VTS_ROOT_PATH");
	if (vtsRootPath && strlen(vtsRootPath) > 0) {
	const std::string halLibraryPathVtsOverride =
	std::string(vtsRootPath) + HAL_LIBRARY_PATH_SYSTEM;
	paths.push_back(halLibraryPathVtsOverride);
	}
	}
	#endif
	for (const std::string& path : paths) {
	std::vector<std::string> libs = search(path, prefix, ".so");

	for (const std::string &lib : libs) {
	const std::string fullPath = path + lib;

	if (path != HAL_LIBRARY_PATH_SYSTEM) {
	handle = android_load_sphal_library(fullPath.c_str(), dlMode);
	} else {
	handle = dlopen(fullPath.c_str(), dlMode);
	}

	if (handle == nullptr) {
	const char* error = dlerror();
	LOG(ERROR) << "Failed to dlopen " << lib << ": "
	<< (error == nullptr ? "unknown error" : error);
	continue;
	}

	if (!eachLib(handle, lib, sym)) {
	return;
	}
	}
	}
	}

	Return<sp<IBase>> get(const hidl_string& fqName,
	const hidl_string& name) override {
	sp<IBase> ret = nullptr;

	openLibs(fqName, [&](void* handle, const std::string &lib, const std::string &sym) {
	IBase* (generator)(const char name);
	(void *)(&generator) = dlsym(handle, sym.c_str());
	if(!generator) {
	const char* error = dlerror();
	LOG(ERROR) << "Passthrough lookup opened " << lib
	<< " but could not find symbol " << sym << ": "
	<< (error == nullptr ? "unknown error" : error);
	dlclose(handle);
	return true;
	}

	ret = (*generator)(name.c_str());

	if (ret == nullptr) {
	dlclose(handle);
	return true; // this module doesn't provide this instance name
	}

	registerReference(fqName, name);
	return false;
	});

	return ret;
	}

	Return<bool> add(const hidl_string& /* name */,
	const sp<IBase>& /* service */) override {
	LOG(FATAL) << "Cannot register services with passthrough service manager.";
	return false;
	}

	Return<Transport> getTransport(const hidl_string& /* fqName */,
	const hidl_string& /* name */) {
	LOG(FATAL) << "Cannot getTransport with passthrough service manager.";
	return Transport::EMPTY;
	}

	Return<void> list(list_cb /* _hidl_cb */) override {
	LOG(FATAL) << "Cannot list services with passthrough service manager.";
	return Void();
	}
	Return<void> listByInterface(const hidl_string& /* fqInstanceName */,
	listByInterface_cb /* _hidl_cb */) override {
	// TODO: add this functionality
	LOG(FATAL) << "Cannot list services with passthrough service manager.";
	return Void();
	}

	Return<bool> registerForNotifications(const hidl_string& /* fqName */,
	const hidl_string& /* name */,
	const sp<IServiceNotification>& /* callback */) override {
	// This makes no sense.
	LOG(FATAL) << "Cannot register for notifications with passthrough service manager.";
	return false;
	}

	Return<void> debugDump(debugDump_cb _hidl_cb) override {
	using Arch = ::android::hidl::base::V1_0::DebugInfo::Architecture;
	using std::literals::string_literals::operator""s;
	static std::vector<std::pair<Arch, std::vector<const char*>>> sAllPaths{
	{Arch::IS_64BIT,
	{HAL_LIBRARY_PATH_ODM_64BIT, HAL_LIBRARY_PATH_VENDOR_64BIT,
	HAL_LIBRARY_PATH_VNDK_SP_64BIT, HAL_LIBRARY_PATH_SYSTEM_64BIT}},
	{Arch::IS_32BIT,
	{HAL_LIBRARY_PATH_ODM_32BIT, HAL_LIBRARY_PATH_VENDOR_32BIT,
	HAL_LIBRARY_PATH_VNDK_SP_32BIT, HAL_LIBRARY_PATH_SYSTEM_32BIT}}};
	std::map<std::string, InstanceDebugInfo> map;
	for (const auto &pair : sAllPaths) {
	Arch arch = pair.first;
	for (const auto &path : pair.second) {
	std::vector<std::string> libs = search(path, "", ".so");
	for (const std::string &lib : libs) {
	std::string matchedName;
	std::string implName;
	if (matchPackageName(lib, &matchedName, &implName)) {
	std::string instanceName{"* ("s + path + ")"s};
	if (!implName.empty()) instanceName += " ("s + implName + ")"s;
	map.emplace(path + lib, InstanceDebugInfo{.interfaceName = matchedName,
	.instanceName = instanceName,
	.clientPids = {},
	.arch = arch});
	}
	}
	}
	}
	fetchPidsForPassthroughLibraries(&map);
	hidl_vec<InstanceDebugInfo> vec;
	vec.resize(map.size());
	size_t idx = 0;
	for (auto&& pair : map) {
	vec[idx++] = std::move(pair.second);
	}
	_hidl_cb(vec);
	return Void();
	}

	Return<void> registerPassthroughClient(const hidl_string &, const hidl_string &) override {
	// This makes no sense.
	LOG(FATAL) << "Cannot call registerPassthroughClient on passthrough service manager. "
	<< "Call it on defaultServiceManager() instead.";
	return Void();
	}

	Return<bool> unregisterForNotifications(const hidl_string& /* fqName */,
	const hidl_string& /* name */,
	const sp<IServiceNotification>& /* callback */) override {
	// This makes no sense.
	LOG(FATAL) << "Cannot unregister for notifications with passthrough service manager.";
	return false;
	}

	};

	sp<IServiceManager1_0> getPassthroughServiceManager() {
	return getPassthroughServiceManager1_1();
	}
	sp<IServiceManager1_1> getPassthroughServiceManager1_1() {
	static sp<PassthroughServiceManager> manager(new PassthroughServiceManager());
	return manager;
	}

	namespace details {

	void preloadPassthroughService(const std::string &descriptor) {
	PassthroughServiceManager::openLibs(descriptor,
	[&](void* /* handle /, const std::string& / lib /, const std::string& / sym */) {
	// do nothing
	return true; // open all libs
	});
	}

	struct Waiter : IServiceNotification {
	Return<void> onRegistration(const hidl_string& /* fqName */,
	const hidl_string& /* name */,
	bool /* preexisting */) override {
	std::unique_lock<std::mutex> lock(mMutex);
	if (mRegistered) {
	return Void();
	}
	mRegistered = true;
	lock.unlock();

	mCondition.notify_one();
	return Void();
	}

	void wait(const std::string &interface, const std::string &instanceName) {
	using std::literals::chrono_literals::operator""s;

	std::unique_lock<std::mutex> lock(mMutex);
	while(true) {
	mCondition.wait_for(lock, 1s, [this]{
	return mRegistered;
	});

	if (mRegistered) {
	break;
	}

	LOG(WARNING) << "Waited one second for "
	<< interface << "/" << instanceName
	<< ". Waiting another...";
	}
	}

	private:
	std::mutex mMutex;
	std::condition_variable mCondition;
	bool mRegistered = false;
	};

	void waitForHwService(
	const std::string &interface, const std::string &instanceName) {
	const sp<IServiceManager1_1> manager = defaultServiceManager1_1();

	if (manager == nullptr) {
	LOG(ERROR) << "Could not get default service manager.";
	return;
	}

	sp<Waiter> waiter = new Waiter();
	Return<bool> ret = manager->registerForNotifications(interface, instanceName, waiter);

	if (!ret.isOk()) {
	LOG(ERROR) << "Transport error, " << ret.description()
	<< ", during notification registration for "
	<< interface << "/" << instanceName << ".";
	return;
	}

	if (!ret) {
	LOG(ERROR) << "Could not register for notifications for "
	<< interface << "/" << instanceName << ".";
	return;
	}

	waiter->wait(interface, instanceName);

	if (!manager->unregisterForNotifications(interface, instanceName, waiter).withDefault(false)) {
	LOG(ERROR) << "Could not unregister service notification for "
	<< interface << "/" << instanceName << ".";
	}
	}

	}; // namespace details

	}; // namespace hardware
	}; // namespace android