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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 _BACKTRACE_BACKTRACE_H
     18 #define _BACKTRACE_BACKTRACE_H
     19 
     20 #include <inttypes.h>
     21 #include <stdint.h>
     22 
     23 #include <string>
     24 #include <vector>
     25 
     26 #include <backtrace/backtrace_constants.h>
     27 #include <backtrace/BacktraceMap.h>
     28 
     29 #if __LP64__
     30 #define PRIPTR "016" PRIxPTR
     31 typedef uint64_t word_t;
     32 #else
     33 #define PRIPTR "08" PRIxPTR
     34 typedef uint32_t word_t;
     35 #endif
     36 
     37 struct backtrace_frame_data_t {
     38   size_t num;             // The current fame number.
     39   uintptr_t pc;           // The absolute pc.
     40   uintptr_t sp;           // The top of the stack.
     41   size_t stack_size;      // The size of the stack, zero indicate an unknown stack size.
     42   const backtrace_map_t* map;   // The map associated with the given pc.
     43   std::string func_name;  // The function name associated with this pc, NULL if not found.
     44   uintptr_t func_offset;  // pc relative to the start of the function, only valid if func_name is not NULL.
     45 };
     46 
     47 // Forward declarations.
     48 class BacktraceImpl;
     49 
     50 #if defined(__APPLE__)
     51 struct __darwin_ucontext;
     52 typedef __darwin_ucontext ucontext_t;
     53 #else
     54 struct ucontext;
     55 typedef ucontext ucontext_t;
     56 #endif
     57 
     58 class Backtrace {
     59 public:
     60   // Create the correct Backtrace object based on what is to be unwound.
     61   // If pid < 0 or equals the current pid, then the Backtrace object
     62   // corresponds to the current process.
     63   // If pid < 0 or equals the current pid and tid >= 0, then the Backtrace
     64   // object corresponds to a thread in the current process.
     65   // If pid >= 0 and tid < 0, then the Backtrace object corresponds to a
     66   // different process.
     67   // Tracing a thread in a different process is not supported.
     68   // If map is NULL, then create the map and manage it internally.
     69   // If map is not NULL, the map is still owned by the caller.
     70   static Backtrace* Create(pid_t pid, pid_t tid, BacktraceMap* map = NULL);
     71 
     72   virtual ~Backtrace();
     73 
     74   // Get the current stack trace and store in the backtrace_ structure.
     75   virtual bool Unwind(size_t num_ignore_frames, ucontext_t* context = NULL);
     76 
     77   // Get the function name and offset into the function given the pc.
     78   // If the string is empty, then no valid function name was found.
     79   virtual std::string GetFunctionName(uintptr_t pc, uintptr_t* offset);
     80 
     81   // Find the map associated with the given pc.
     82   virtual const backtrace_map_t* FindMap(uintptr_t pc);
     83 
     84   // Read the data at a specific address.
     85   virtual bool ReadWord(uintptr_t ptr, word_t* out_value) = 0;
     86 
     87   // Create a string representing the formatted line of backtrace information
     88   // for a single frame.
     89   virtual std::string FormatFrameData(size_t frame_num);
     90   virtual std::string FormatFrameData(const backtrace_frame_data_t* frame);
     91 
     92   pid_t Pid() { return pid_; }
     93   pid_t Tid() { return tid_; }
     94   size_t NumFrames() { return frames_.size(); }
     95 
     96   const backtrace_frame_data_t* GetFrame(size_t frame_num) {
     97     if (frame_num >= frames_.size()) {
     98       return NULL;
     99     }
    100     return &frames_[frame_num];
    101   }
    102 
    103   typedef std::vector<backtrace_frame_data_t>::iterator iterator;
    104   iterator begin() { return frames_.begin(); }
    105   iterator end() { return frames_.end(); }
    106 
    107   typedef std::vector<backtrace_frame_data_t>::const_iterator const_iterator;
    108   const_iterator begin() const { return frames_.begin(); }
    109   const_iterator end() const { return frames_.end(); }
    110 
    111   BacktraceMap* GetMap() { return map_; }
    112 
    113 protected:
    114   Backtrace(BacktraceImpl* impl, pid_t pid, BacktraceMap* map);
    115 
    116   virtual bool VerifyReadWordArgs(uintptr_t ptr, word_t* out_value);
    117 
    118   bool BuildMap();
    119 
    120   pid_t pid_;
    121   pid_t tid_;
    122 
    123   BacktraceMap* map_;
    124   bool map_shared_;
    125 
    126   std::vector<backtrace_frame_data_t> frames_;
    127 
    128   BacktraceImpl* impl_;
    129 
    130   friend class BacktraceImpl;
    131 };
    132 
    133 #endif // _BACKTRACE_BACKTRACE_H
    134