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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.
*/
#include "ServiceManager.h"
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <binder/BpBinder.h>
#include <binder/IPCThreadState.h>
#include <binder/ProcessState.h>
#include <binder/Stability.h>
#include <cutils/android_filesystem_config.h>
#include <cutils/multiuser.h>
#include <thread>
#ifndef VENDORSERVICEMANAGER
#include <vintf/VintfObject.h>
#include <vintf/constants.h>
#endif // !VENDORSERVICEMANAGER
using ::android::binder::Status;
using ::android::internal::Stability;
namespace android {
#ifndef VENDORSERVICEMANAGER
struct ManifestWithDescription {
std::shared_ptr<const vintf::HalManifest> manifest;
const char* description;
};
// func true -> stop search and forEachManifest will return true
static bool forEachManifest(const std::function<bool(const ManifestWithDescription&)>& func) {
for (const ManifestWithDescription& mwd : {
ManifestWithDescription{ vintf::VintfObject::GetDeviceHalManifest(), "device" },
ManifestWithDescription{ vintf::VintfObject::GetFrameworkHalManifest(), "framework" },
}) {
if (mwd.manifest == nullptr) {
LOG(ERROR) << "NULL VINTF MANIFEST!: " << mwd.description;
// note, we explicitly do not retry here, so that we can detect VINTF
// or other bugs (b/151696835)
continue;
}
if (func(mwd)) return true;
}
return false;
}
struct AidlName {
std::string package;
std::string iface;
std::string instance;
static bool fill(const std::string& name, AidlName* aname) {
size_t firstSlash = name.find('/');
size_t lastDot = name.rfind('.', firstSlash);
if (firstSlash == std::string::npos || lastDot == std::string::npos) {
LOG(ERROR) << "VINTF HALs require names in the format type/instance (e.g. "
<< "some.package.foo.IFoo/default) but got: " << name;
return false;
}
aname->package = name.substr(0, lastDot);
aname->iface = name.substr(lastDot + 1, firstSlash - lastDot - 1);
aname->instance = name.substr(firstSlash + 1);
return true;
}
};
static bool isVintfDeclared(const std::string& name) {
AidlName aname;
if (!AidlName::fill(name, &aname)) return false;
bool found = forEachManifest([&](const ManifestWithDescription& mwd) {
if (mwd.manifest->hasAidlInstance(aname.package, aname.iface, aname.instance)) {
LOG(INFO) << "Found " << name << " in " << mwd.description << " VINTF manifest.";
return true; // break
}
return false; // continue
});
if (!found) {
// Although it is tested, explicitly rebuilding qualified name, in case it
// becomes something unexpected.
LOG(ERROR) << "Could not find " << aname.package << "." << aname.iface << "/"
<< aname.instance << " in the VINTF manifest.";
}
return found;
}
static std::optional<std::string> getVintfUpdatableApex(const std::string& name) {
AidlName aname;
if (!AidlName::fill(name, &aname)) return std::nullopt;
std::optional<std::string> updatableViaApex;
forEachManifest([&](const ManifestWithDescription& mwd) {
mwd.manifest->forEachInstance([&](const auto& manifestInstance) {
if (manifestInstance.format() != vintf::HalFormat::AIDL) return true;
if (manifestInstance.package() != aname.package) return true;
if (manifestInstance.interface() != aname.iface) return true;
if (manifestInstance.instance() != aname.instance) return true;
updatableViaApex = manifestInstance.updatableViaApex();
return false; // break (libvintf uses opposite convention)
});
return false; // continue
});
return updatableViaApex;
}
static std::vector<std::string> getVintfInstances(const std::string& interface) {
size_t lastDot = interface.rfind('.');
if (lastDot == std::string::npos) {
LOG(ERROR) << "VINTF interfaces require names in Java package format (e.g. some.package.foo.IFoo) but got: " << interface;
return {};
}
const std::string package = interface.substr(0, lastDot);
const std::string iface = interface.substr(lastDot+1);
std::vector<std::string> ret;
(void)forEachManifest([&](const ManifestWithDescription& mwd) {
auto instances = mwd.manifest->getAidlInstances(package, iface);
ret.insert(ret.end(), instances.begin(), instances.end());
return false; // continue
});
return ret;
}
static bool meetsDeclarationRequirements(const sp<IBinder>& binder, const std::string& name) {
if (!Stability::requiresVintfDeclaration(binder)) {
return true;
}
return isVintfDeclared(name);
}
#endif // !VENDORSERVICEMANAGER
ServiceManager::ServiceManager(std::unique_ptr<Access>&& access) : mAccess(std::move(access)) {
// TODO(b/151696835): reenable performance hack when we solve bug, since with
// this hack and other fixes, it is unlikely we will see even an ephemeral
// failure when the manifest parse fails. The goal is that the manifest will
// be read incorrectly and cause the process trying to register a HAL to
// fail. If this is in fact an early boot kernel contention issue, then we
// will get no failure, and by its absence, be signalled to invest more
// effort in re-adding this performance hack.
// #ifndef VENDORSERVICEMANAGER
// // can process these at any times, don't want to delay first VINTF client
// std::thread([] {
// vintf::VintfObject::GetDeviceHalManifest();
// vintf::VintfObject::GetFrameworkHalManifest();
// }).detach();
// #endif // !VENDORSERVICEMANAGER
}
ServiceManager::~ServiceManager() {
// this should only happen in tests
for (const auto& [name, callbacks] : mNameToRegistrationCallback) {
CHECK(!callbacks.empty()) << name;
for (const auto& callback : callbacks) {
CHECK(callback != nullptr) << name;
}
}
for (const auto& [name, service] : mNameToService) {
CHECK(service.binder != nullptr) << name;
}
}
Status ServiceManager::getService(const std::string& name, sp<IBinder>* outBinder) {
*outBinder = tryGetService(name, true);
// returns ok regardless of result for legacy reasons
return Status::ok();
}
Status ServiceManager::checkService(const std::string& name, sp<IBinder>* outBinder) {
*outBinder = tryGetService(name, false);
// returns ok regardless of result for legacy reasons
return Status::ok();
}
sp<IBinder> ServiceManager::tryGetService(const std::string& name, bool startIfNotFound) {
auto ctx = mAccess->getCallingContext();
sp<IBinder> out;
Service* service = nullptr;
if (auto it = mNameToService.find(name); it != mNameToService.end()) {
service = &(it->second);
if (!service->allowIsolated) {
uid_t appid = multiuser_get_app_id(ctx.uid);
bool isIsolated = appid >= AID_ISOLATED_START && appid <= AID_ISOLATED_END;
if (isIsolated) {
return nullptr;
}
}
out = service->binder;
}
if (!mAccess->canFind(ctx, name)) {
return nullptr;
}
if (!out && startIfNotFound) {
tryStartService(name);
}
if (out) {
// Setting this guarantee each time we hand out a binder ensures that the client-checking
// loop knows about the event even if the client immediately drops the service
service->guaranteeClient = true;
}
return out;
}
bool isValidServiceName(const std::string& name) {
if (name.size() == 0) return false;
if (name.size() > 127) return false;
for (char c : name) {
if (c == '_' || c == '-' || c == '.' || c == '/') continue;
if (c >= 'a' && c <= 'z') continue;
if (c >= 'A' && c <= 'Z') continue;
if (c >= '0' && c <= '9') continue;
return false;
}
return true;
}
Status ServiceManager::addService(const std::string& name, const sp<IBinder>& binder, bool allowIsolated, int32_t dumpPriority) {
auto ctx = mAccess->getCallingContext();
// apps cannot add services
if (multiuser_get_app_id(ctx.uid) >= AID_APP) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
if (!mAccess->canAdd(ctx, name)) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
if (binder == nullptr) {
return Status::fromExceptionCode(Status::EX_ILLEGAL_ARGUMENT);
}
if (!isValidServiceName(name)) {
LOG(ERROR) << "Invalid service name: " << name;
return Status::fromExceptionCode(Status::EX_ILLEGAL_ARGUMENT);
}
#ifndef VENDORSERVICEMANAGER
if (!meetsDeclarationRequirements(binder, name)) {
// already logged
return Status::fromExceptionCode(Status::EX_ILLEGAL_ARGUMENT);
}
#endif // !VENDORSERVICEMANAGER
// implicitly unlinked when the binder is removed
if (binder->remoteBinder() != nullptr &&
binder->linkToDeath(sp<ServiceManager>::fromExisting(this)) != OK) {
LOG(ERROR) << "Could not linkToDeath when adding " << name;
return Status::fromExceptionCode(Status::EX_ILLEGAL_STATE);
}
// Overwrite the old service if it exists
mNameToService[name] = Service {
.binder = binder,
.allowIsolated = allowIsolated,
.dumpPriority = dumpPriority,
.debugPid = ctx.debugPid,
};
auto it = mNameToRegistrationCallback.find(name);
if (it != mNameToRegistrationCallback.end()) {
for (const sp<IServiceCallback>& cb : it->second) {
mNameToService[name].guaranteeClient = true;
// permission checked in registerForNotifications
cb->onRegistration(name, binder);
}
}
return Status::ok();
}
Status ServiceManager::listServices(int32_t dumpPriority, std::vector<std::string>* outList) {
if (!mAccess->canList(mAccess->getCallingContext())) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
size_t toReserve = 0;
for (auto const& [name, service] : mNameToService) {
(void) name;
if (service.dumpPriority & dumpPriority) ++toReserve;
}
CHECK(outList->empty());
outList->reserve(toReserve);
for (auto const& [name, service] : mNameToService) {
(void) service;
if (service.dumpPriority & dumpPriority) {
outList->push_back(name);
}
}
return Status::ok();
}
Status ServiceManager::registerForNotifications(
const std::string& name, const sp<IServiceCallback>& callback) {
auto ctx = mAccess->getCallingContext();
if (!mAccess->canFind(ctx, name)) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
if (!isValidServiceName(name)) {
LOG(ERROR) << "Invalid service name: " << name;
return Status::fromExceptionCode(Status::EX_ILLEGAL_ARGUMENT);
}
if (callback == nullptr) {
return Status::fromExceptionCode(Status::EX_NULL_POINTER);
}
if (OK !=
IInterface::asBinder(callback)->linkToDeath(
sp<ServiceManager>::fromExisting(this))) {
LOG(ERROR) << "Could not linkToDeath when adding " << name;
return Status::fromExceptionCode(Status::EX_ILLEGAL_STATE);
}
mNameToRegistrationCallback[name].push_back(callback);
if (auto it = mNameToService.find(name); it != mNameToService.end()) {
const sp<IBinder>& binder = it->second.binder;
// never null if an entry exists
CHECK(binder != nullptr) << name;
callback->onRegistration(name, binder);
}
return Status::ok();
}
Status ServiceManager::unregisterForNotifications(
const std::string& name, const sp<IServiceCallback>& callback) {
auto ctx = mAccess->getCallingContext();
if (!mAccess->canFind(ctx, name)) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
bool found = false;
auto it = mNameToRegistrationCallback.find(name);
if (it != mNameToRegistrationCallback.end()) {
removeRegistrationCallback(IInterface::asBinder(callback), &it, &found);
}
if (!found) {
LOG(ERROR) << "Trying to unregister callback, but none exists " << name;
return Status::fromExceptionCode(Status::EX_ILLEGAL_STATE);
}
return Status::ok();
}
Status ServiceManager::isDeclared(const std::string& name, bool* outReturn) {
auto ctx = mAccess->getCallingContext();
if (!mAccess->canFind(ctx, name)) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
*outReturn = false;
#ifndef VENDORSERVICEMANAGER
*outReturn = isVintfDeclared(name);
#endif
return Status::ok();
}
binder::Status ServiceManager::getDeclaredInstances(const std::string& interface, std::vector<std::string>* outReturn) {
auto ctx = mAccess->getCallingContext();
std::vector<std::string> allInstances;
#ifndef VENDORSERVICEMANAGER
allInstances = getVintfInstances(interface);
#endif
outReturn->clear();
for (const std::string& instance : allInstances) {
if (mAccess->canFind(ctx, interface + "/" + instance)) {
outReturn->push_back(instance);
}
}
if (outReturn->size() == 0 && allInstances.size() != 0) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
return Status::ok();
}
Status ServiceManager::updatableViaApex(const std::string& name,
std::optional<std::string>* outReturn) {
auto ctx = mAccess->getCallingContext();
if (!mAccess->canFind(ctx, name)) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
*outReturn = std::nullopt;
#ifndef VENDORSERVICEMANAGER
*outReturn = getVintfUpdatableApex(name);
#endif
return Status::ok();
}
void ServiceManager::removeRegistrationCallback(const wp<IBinder>& who,
ServiceCallbackMap::iterator* it,
bool* found) {
std::vector<sp<IServiceCallback>>& listeners = (*it)->second;
for (auto lit = listeners.begin(); lit != listeners.end();) {
if (IInterface::asBinder(*lit) == who) {
if(found) *found = true;
lit = listeners.erase(lit);
} else {
++lit;
}
}
if (listeners.empty()) {
*it = mNameToRegistrationCallback.erase(*it);
} else {
(*it)++;
}
}
void ServiceManager::binderDied(const wp<IBinder>& who) {
for (auto it = mNameToService.begin(); it != mNameToService.end();) {
if (who == it->second.binder) {
it = mNameToService.erase(it);
} else {
++it;
}
}
for (auto it = mNameToRegistrationCallback.begin(); it != mNameToRegistrationCallback.end();) {
removeRegistrationCallback(who, &it, nullptr /*found*/);
}
for (auto it = mNameToClientCallback.begin(); it != mNameToClientCallback.end();) {
removeClientCallback(who, &it);
}
}
void ServiceManager::tryStartService(const std::string& name) {
ALOGI("Since '%s' could not be found, trying to start it as a lazy AIDL service",
name.c_str());
std::thread([=] {
if (!base::SetProperty("ctl.interface_start", "aidl/" + name)) {
LOG(INFO) << "Tried to start aidl service " << name
<< " as a lazy service, but was unable to. Usually this happens when a "
"service is not installed, but if the service is intended to be used as a "
"lazy service, then it may be configured incorrectly.";
}
}).detach();
}
Status ServiceManager::registerClientCallback(const std::string& name, const sp<IBinder>& service,
const sp<IClientCallback>& cb) {
if (cb == nullptr) {
return Status::fromExceptionCode(Status::EX_NULL_POINTER);
}
auto ctx = mAccess->getCallingContext();
if (!mAccess->canAdd(ctx, name)) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
auto serviceIt = mNameToService.find(name);
if (serviceIt == mNameToService.end()) {
LOG(ERROR) << "Could not add callback for nonexistent service: " << name;
return Status::fromExceptionCode(Status::EX_ILLEGAL_ARGUMENT);
}
if (serviceIt->second.debugPid != IPCThreadState::self()->getCallingPid()) {
LOG(WARNING) << "Only a server can register for client callbacks (for " << name << ")";
return Status::fromExceptionCode(Status::EX_UNSUPPORTED_OPERATION);
}
if (serviceIt->second.binder != service) {
LOG(WARNING) << "Tried to register client callback for " << name
<< " but a different service is registered under this name.";
return Status::fromExceptionCode(Status::EX_ILLEGAL_ARGUMENT);
}
if (OK !=
IInterface::asBinder(cb)->linkToDeath(sp<ServiceManager>::fromExisting(this))) {
LOG(ERROR) << "Could not linkToDeath when adding client callback for " << name;
return Status::fromExceptionCode(Status::EX_ILLEGAL_STATE);
}
mNameToClientCallback[name].push_back(cb);
return Status::ok();
}
void ServiceManager::removeClientCallback(const wp<IBinder>& who,
ClientCallbackMap::iterator* it) {
std::vector<sp<IClientCallback>>& listeners = (*it)->second;
for (auto lit = listeners.begin(); lit != listeners.end();) {
if (IInterface::asBinder(*lit) == who) {
lit = listeners.erase(lit);
} else {
++lit;
}
}
if (listeners.empty()) {
*it = mNameToClientCallback.erase(*it);
} else {
(*it)++;
}
}
ssize_t ServiceManager::Service::getNodeStrongRefCount() {
sp<BpBinder> bpBinder = sp<BpBinder>::fromExisting(binder->remoteBinder());
if (bpBinder == nullptr) return -1;
return ProcessState::self()->getStrongRefCountForNode(bpBinder);
}
void ServiceManager::handleClientCallbacks() {
for (const auto& [name, service] : mNameToService) {
handleServiceClientCallback(name, true);
}
}
ssize_t ServiceManager::handleServiceClientCallback(const std::string& serviceName,
bool isCalledOnInterval) {
auto serviceIt = mNameToService.find(serviceName);
if (serviceIt == mNameToService.end() || mNameToClientCallback.count(serviceName) < 1) {
return -1;
}
Service& service = serviceIt->second;
ssize_t count = service.getNodeStrongRefCount();
// binder driver doesn't support this feature
if (count == -1) return count;
bool hasClients = count > 1; // this process holds a strong count
if (service.guaranteeClient) {
// we have no record of this client
if (!service.hasClients && !hasClients) {
sendClientCallbackNotifications(serviceName, true);
}
// guarantee is temporary
service.guaranteeClient = false;
}
// only send notifications if this was called via the interval checking workflow
if (isCalledOnInterval) {
if (hasClients && !service.hasClients) {
// client was retrieved in some other way
sendClientCallbackNotifications(serviceName, true);
}
// there are no more clients, but the callback has not been called yet
if (!hasClients && service.hasClients) {
sendClientCallbackNotifications(serviceName, false);
}
}
return count;
}
void ServiceManager::sendClientCallbackNotifications(const std::string& serviceName, bool hasClients) {
auto serviceIt = mNameToService.find(serviceName);
if (serviceIt == mNameToService.end()) {
LOG(WARNING) << "sendClientCallbackNotifications could not find service " << serviceName;
return;
}
Service& service = serviceIt->second;
CHECK(hasClients != service.hasClients) << "Record shows: " << service.hasClients
<< " so we can't tell clients again that we have client: " << hasClients;
LOG(INFO) << "Notifying " << serviceName << " they have clients: " << hasClients;
auto ccIt = mNameToClientCallback.find(serviceName);
CHECK(ccIt != mNameToClientCallback.end())
<< "sendClientCallbackNotifications could not find callbacks for service ";
for (const auto& callback : ccIt->second) {
callback->onClients(service.binder, hasClients);
}
service.hasClients = hasClients;
}
Status ServiceManager::tryUnregisterService(const std::string& name, const sp<IBinder>& binder) {
if (binder == nullptr) {
return Status::fromExceptionCode(Status::EX_NULL_POINTER);
}
auto ctx = mAccess->getCallingContext();
if (!mAccess->canAdd(ctx, name)) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
auto serviceIt = mNameToService.find(name);
if (serviceIt == mNameToService.end()) {
LOG(WARNING) << "Tried to unregister " << name
<< ", but that service wasn't registered to begin with.";
return Status::fromExceptionCode(Status::EX_ILLEGAL_STATE);
}
if (serviceIt->second.debugPid != IPCThreadState::self()->getCallingPid()) {
LOG(WARNING) << "Only a server can unregister itself (for " << name << ")";
return Status::fromExceptionCode(Status::EX_UNSUPPORTED_OPERATION);
}
sp<IBinder> storedBinder = serviceIt->second.binder;
if (binder != storedBinder) {
LOG(WARNING) << "Tried to unregister " << name
<< ", but a different service is registered under this name.";
return Status::fromExceptionCode(Status::EX_ILLEGAL_STATE);
}
if (serviceIt->second.guaranteeClient) {
LOG(INFO) << "Tried to unregister " << name << ", but there is about to be a client.";
return Status::fromExceptionCode(Status::EX_ILLEGAL_STATE);
}
int clients = handleServiceClientCallback(name, false);
// clients < 0: feature not implemented or other error. Assume clients.
// Otherwise:
// - kernel driver will hold onto one refcount (during this transaction)
// - servicemanager has a refcount (guaranteed by this transaction)
// So, if clients > 2, then at least one other service on the system must hold a refcount.
if (clients < 0 || clients > 2) {
// client callbacks are either disabled or there are other clients
LOG(INFO) << "Tried to unregister " << name << ", but there are clients: " << clients;
// Set this flag to ensure the clients are acknowledged in the next callback
serviceIt->second.guaranteeClient = true;
return Status::fromExceptionCode(Status::EX_ILLEGAL_STATE);
}
mNameToService.erase(name);
return Status::ok();
}
Status ServiceManager::getServiceDebugInfo(std::vector<ServiceDebugInfo>* outReturn) {
if (!mAccess->canList(mAccess->getCallingContext())) {
return Status::fromExceptionCode(Status::EX_SECURITY);
}
outReturn->reserve(mNameToService.size());
for (auto const& [name, service] : mNameToService) {
ServiceDebugInfo info;
info.name = name;
info.debugPid = service.debugPid;
outReturn->push_back(std::move(info));
}
return Status::ok();
}
} // namespace android