1 /*
2  * Copyright (C) 2013 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 #ifndef _LIBUNWINDSTACK_THREAD_ENTRY_H
18 #define _LIBUNWINDSTACK_THREAD_ENTRY_H
19 
20 #include <pthread.h>
21 #include <sys/types.h>
22 #include <ucontext.h>
23 
24 #include <condition_variable>
25 #include <map>
26 #include <mutex>
27 
28 namespace unwindstack {
29 
30 enum WaitType : int {
31   WAIT_FOR_UCONTEXT = 1,
32   WAIT_FOR_UNWIND_TO_COMPLETE,
33   WAIT_FOR_THREAD_TO_RESTART,
34 };
35 
36 class ThreadEntry {
37  public:
38   static ThreadEntry* Get(pid_t tid, bool create = true);
39 
40   static void Remove(ThreadEntry* entry);
41 
42   void Wake();
43 
44   bool Wait(WaitType type);
45 
46   void CopyUcontextFromSigcontext(void* sigcontext);
47 
Lock()48   inline void Lock() {
49     mutex_.lock();
50 
51     // Always reset the wait value since this could be the first or nth
52     // time this entry is locked.
53     wait_value_ = 0;
54   }
55 
Unlock()56   inline void Unlock() { mutex_.unlock(); }
57 
GetUcontext()58   inline ucontext_t* GetUcontext() { return &ucontext_; }
59 
60  private:
61   ThreadEntry(pid_t tid);
62   ~ThreadEntry();
63 
64   pid_t tid_;
65   int ref_count_;
66   std::mutex mutex_;
67   std::mutex wait_mutex_;
68   std::condition_variable wait_cond_;
69   int wait_value_;
70   ucontext_t ucontext_;
71 
72   static std::mutex entries_mutex_;
73   static std::map<pid_t, ThreadEntry*> entries_;
74 };
75 
76 }  // namespace unwindstack
77 
78 #endif  // _LIBUNWINDSTACK_THREAD_ENTRY_H
79