1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
/*
* 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), mForcePersist(false) {}
bool registerService(const sp<IBinder>& service, const std::string& name,
bool allowIsolated, int dumpFlags);
/**
* Set a flag to prevent services from automatically shutting down
*/
void forcePersist(bool persist);
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 mForcePersist;
};
bool ClientCounterCallback::registerService(const sp<IBinder>& service, const std::string& name,
bool allowIsolated, int dumpFlags) {
auto manager = interface_cast<AidlServiceManager>(asBinder(defaultServiceManager()));
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 (!reRegister) {
if (!manager->registerClientCallback(name, service, this).isOk()) {
ALOGE("Failed to add client callback for service %s", name.c_str());
return false;
}
// Only add this when a service is added for the first time, as it is not removed
mRegisteredServices[name] = {service, allowIsolated, dumpFlags};
}
return true;
}
void ClientCounterCallback::forcePersist(bool persist) {
mForcePersist = persist;
if(!mForcePersist) {
// Attempt a shutdown in case the number of clients hit 0 while the flag was on
tryShutdown();
}
}
/**
* 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);
tryShutdown();
return Status::ok();
}
void ClientCounterCallback::tryShutdown() {
if(mNumConnectedServices > 0) {
// Should only shut down if there are no clients
return;
}
if(mForcePersist) {
ALOGI("Shutdown prevented by forcePersist override flag.");
return;
}
ALOGI("Trying to shut down the service. No clients in use for any service in process.");
auto manager = interface_cast<AidlServiceManager>(asBinder(defaultServiceManager()));
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;
}
void LazyServiceRegistrar::forcePersist(bool persist) {
mClientCC->forcePersist(persist);
}
} // namespace hardware
} // namespace android
|
