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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 #include <ucontext.h>
     23 
     24 #include <backtrace/Backtrace.h>
     25 
     26 // The signal used to cause a thread to dump the stack.
     27 #if defined(__GLIBC__)
     28 // In order to run the backtrace_tests on the host, we can't use
     29 // the internal real time signals used by GLIBC. To avoid this,
     30 // use SIGRTMIN for the signal to dump the stack.
     31 #define THREAD_SIGNAL SIGRTMIN
     32 #else
     33 #define THREAD_SIGNAL (__SIGRTMIN+1)
     34 #endif
     35 
     36 class BacktraceMap;
     37 
     38 class BacktraceCurrent : public Backtrace {
     39  public:
     40   BacktraceCurrent(pid_t pid, pid_t tid, BacktraceMap* map) : Backtrace(pid, tid, map) {}
     41   virtual ~BacktraceCurrent() {}
     42 
     43   size_t Read(uintptr_t addr, uint8_t* buffer, size_t bytes) override;
     44 
     45   bool ReadWord(uintptr_t ptr, word_t* out_value) override;
     46 
     47   bool Unwind(size_t num_ignore_frames, ucontext_t* ucontext) override;
     48 
     49  protected:
     50   bool DiscardFrame(const backtrace_frame_data_t& frame);
     51 
     52  private:
     53   bool UnwindThread(size_t num_ignore_frames);
     54 
     55   virtual bool UnwindFromContext(size_t num_ignore_frames, ucontext_t* ucontext) = 0;
     56 };
     57 
     58 #endif // _LIBBACKTRACE_BACKTRACE_CURRENT_H
     59