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      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 _LIBBACKTRACE_BACKTRACE_THREAD_H
     18 #define _LIBBACKTRACE_BACKTRACE_THREAD_H
     19 
     20 #include <inttypes.h>
     21 #include <pthread.h>
     22 #include <signal.h>
     23 #include <string.h>
     24 #include <sys/types.h>
     25 #include <ucontext.h>
     26 
     27 #include "BacktraceImpl.h"
     28 
     29 // The signal used to cause a thread to dump the stack.
     30 #if defined(__GLIBC__)
     31 // GLIBC reserves __SIGRTMIN signals, so use SIGRTMIN to avoid errors.
     32 #define THREAD_SIGNAL SIGRTMIN
     33 #else
     34 #define THREAD_SIGNAL (__SIGRTMIN+1)
     35 #endif
     36 
     37 class ThreadEntry {
     38 public:
     39   static ThreadEntry* Get(pid_t pid, pid_t tid, bool create = true);
     40 
     41   static void Remove(ThreadEntry* entry);
     42 
     43   void Wake();
     44 
     45   void Wait(int);
     46 
     47   void CopyUcontextFromSigcontext(void*);
     48 
     49   inline void Lock() {
     50     pthread_mutex_lock(&mutex_);
     51     // Reset the futex value in case of multiple unwinds of the same thread.
     52     futex_ = 0;
     53   }
     54 
     55   inline void Unlock() {
     56     pthread_mutex_unlock(&mutex_);
     57   }
     58 
     59   inline ucontext_t* GetUcontext() { return &ucontext_; }
     60 
     61 private:
     62   ThreadEntry(pid_t pid, pid_t tid);
     63   ~ThreadEntry();
     64 
     65   bool Match(pid_t chk_pid, pid_t chk_tid) { return (chk_pid == pid_ && chk_tid == tid_); }
     66 
     67   pid_t pid_;
     68   pid_t tid_;
     69   int futex_;
     70   int ref_count_;
     71   pthread_mutex_t mutex_;
     72   ThreadEntry* next_;
     73   ThreadEntry* prev_;
     74   ucontext_t ucontext_;
     75 
     76   static ThreadEntry* list_;
     77   static pthread_mutex_t list_mutex_;
     78 };
     79 
     80 class BacktraceThread : public BacktraceCurrent {
     81 public:
     82   BacktraceThread(BacktraceImpl* impl, pid_t tid, BacktraceMap* map);
     83   virtual ~BacktraceThread();
     84 
     85   virtual bool Unwind(size_t num_ignore_frames, ucontext_t* ucontext);
     86 };
     87 
     88 #endif // _LIBBACKTRACE_BACKTRACE_THREAD_H
     89