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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 
     52     // Always reset the wait value since this could be the first or nth
     53     // time this entry is locked.
     54     wait_value_ = 0;
     55   }
     56 
     57   inline void Unlock() {
     58     pthread_mutex_unlock(&mutex_);
     59   }
     60 
     61   inline ucontext_t* GetUcontext() { return &ucontext_; }
     62 
     63 private:
     64   ThreadEntry(pid_t pid, pid_t tid);
     65   ~ThreadEntry();
     66 
     67   bool Match(pid_t chk_pid, pid_t chk_tid) { return (chk_pid == pid_ && chk_tid == tid_); }
     68 
     69   pid_t pid_;
     70   pid_t tid_;
     71   int ref_count_;
     72   pthread_mutex_t mutex_;
     73   pthread_mutex_t wait_mutex_;
     74   pthread_cond_t wait_cond_;
     75   int wait_value_;
     76   ThreadEntry* next_;
     77   ThreadEntry* prev_;
     78   ucontext_t ucontext_;
     79 
     80   static ThreadEntry* list_;
     81   static pthread_mutex_t list_mutex_;
     82 };
     83 
     84 class BacktraceThread : public BacktraceCurrent {
     85 public:
     86   BacktraceThread(BacktraceImpl* impl, pid_t tid, BacktraceMap* map);
     87   virtual ~BacktraceThread();
     88 
     89   virtual bool Unwind(size_t num_ignore_frames, ucontext_t* ucontext);
     90 };
     91 
     92 #endif // _LIBBACKTRACE_BACKTRACE_THREAD_H
     93