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1 /*
2  * Copyright (C) 2018 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #define LOG_TAG "IPCThreadStateBase"
18 
19 #include <binderthreadstate/IPCThreadStateBase.h>
20 #include <android-base/macros.h>
21 
22 #include <utils/Log.h>
23 
24 #include <errno.h>
25 #include <inttypes.h>
26 #include <pthread.h>
27 
28 namespace android {
29 
30 static pthread_mutex_t gTLSMutex = PTHREAD_MUTEX_INITIALIZER;
31 static bool gHaveTLS = false;
32 static pthread_key_t gTLS = 0;
33 
IPCThreadStateBase()34 IPCThreadStateBase::IPCThreadStateBase() {
35     pthread_setspecific(gTLS, this);
36 }
37 
self()38 IPCThreadStateBase* IPCThreadStateBase::self()
39 {
40     if (gHaveTLS) {
41 restart:
42         const pthread_key_t k = gTLS;
43         IPCThreadStateBase* st = (IPCThreadStateBase*)pthread_getspecific(k);
44         if (st) return st;
45         return new IPCThreadStateBase;
46     }
47 
48     pthread_mutex_lock(&gTLSMutex);
49     if (!gHaveTLS) {
50         int key_create_value = pthread_key_create(&gTLS, threadDestructor);
51         if (key_create_value != 0) {
52             pthread_mutex_unlock(&gTLSMutex);
53             ALOGW("IPCThreadStateBase::self() unable to create TLS key, expect a crash: %s\n",
54                     strerror(key_create_value));
55             return nullptr;
56         }
57         gHaveTLS = true;
58     }
59     pthread_mutex_unlock(&gTLSMutex);
60     goto restart;
61 }
62 
pushCurrentState(CallState callState)63 void IPCThreadStateBase::pushCurrentState(CallState callState) {
64     mCallStateStack.emplace(callState);
65 }
66 
popCurrentState()67 IPCThreadStateBase::CallState IPCThreadStateBase::popCurrentState() {
68     ALOG_ASSERT(mCallStateStack.size > 0);
69     CallState val = mCallStateStack.top();
70     mCallStateStack.pop();
71     return val;
72 }
73 
getCurrentBinderCallState()74 IPCThreadStateBase::CallState IPCThreadStateBase::getCurrentBinderCallState() {
75     if (mCallStateStack.size() > 0) {
76         return mCallStateStack.top();
77     }
78     return CallState::NONE;
79 }
80 
threadDestructor(void * st)81 void IPCThreadStateBase::threadDestructor(void *st)
82 {
83     IPCThreadStateBase* const self = static_cast<IPCThreadStateBase*>(st);
84     if (self) {
85         delete self;
86     }
87 }
88 
89 }; // namespace android
90