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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_CURRENT_H
     18 #define _LIBBACKTRACE_BACKTRACE_CURRENT_H
     19 
     20 #include <stdint.h>
     21 #include <sys/types.h>
     22 
     23 #include <backtrace/Backtrace.h>
     24 
     25 // The signal used to cause a thread to dump the stack.
     26 #if defined(__GLIBC__)
     27 // In order to run the backtrace_tests on the host, we can't use
     28 // the internal real time signals used by GLIBC. To avoid this,
     29 // use SIGRTMIN for the signal to dump the stack.
     30 #define THREAD_SIGNAL SIGRTMIN
     31 #else
     32 #define THREAD_SIGNAL (__SIGRTMIN+1)
     33 #endif
     34 
     35 class BacktraceMap;
     36 
     37 class BacktraceCurrent : public Backtrace {
     38  public:
     39   BacktraceCurrent(pid_t pid, pid_t tid, BacktraceMap* map) : Backtrace(pid, tid, map) {}
     40   virtual ~BacktraceCurrent() {}
     41 
     42   size_t Read(uint64_t addr, uint8_t* buffer, size_t bytes) override;
     43 
     44   bool ReadWord(uint64_t ptr, word_t* out_value) override;
     45 
     46   bool Unwind(size_t num_ignore_frames, void* ucontext) override;
     47 
     48  protected:
     49   bool DiscardFrame(const backtrace_frame_data_t& frame);
     50 
     51  private:
     52   bool UnwindThread(size_t num_ignore_frames);
     53 
     54   virtual bool UnwindFromContext(size_t num_ignore_frames, void* ucontext) = 0;
     55 };
     56 
     57 #endif // _LIBBACKTRACE_BACKTRACE_CURRENT_H
     58