summaryrefslogtreecommitdiff
path: root/libbacktrace/include/backtrace/Backtrace.h
blob: 4f73a658ce3b2f925c7f6ea86d5a7f59432dda01 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _BACKTRACE_BACKTRACE_H
#define _BACKTRACE_BACKTRACE_H

#include <inttypes.h>
#include <stdint.h>

#include <string>
#include <vector>

#include <backtrace/backtrace_constants.h>
#include <backtrace/BacktraceMap.h>

#if __LP64__
#define PRIPTR "016" PRIxPTR
typedef uint64_t word_t;
#else
#define PRIPTR "08" PRIxPTR
typedef uint32_t word_t;
#endif

enum BacktraceUnwindError : uint32_t {
  BACKTRACE_UNWIND_NO_ERROR,
  // Something failed while trying to perform the setup to begin the unwind.
  BACKTRACE_UNWIND_ERROR_SETUP_FAILED,
  // There is no map information to use with the unwind.
  BACKTRACE_UNWIND_ERROR_MAP_MISSING,
  // An error occurred that indicates a programming error.
  BACKTRACE_UNWIND_ERROR_INTERNAL,
  // The thread to unwind has disappeared before the unwind can begin.
  BACKTRACE_UNWIND_ERROR_THREAD_DOESNT_EXIST,
  // The thread to unwind has not responded to a signal in a timely manner.
  BACKTRACE_UNWIND_ERROR_THREAD_TIMEOUT,
  // Attempt to do an unsupported operation.
  BACKTRACE_UNWIND_ERROR_UNSUPPORTED_OPERATION,
  // Attempt to do an offline unwind without a context.
  BACKTRACE_UNWIND_ERROR_NO_CONTEXT,
};

struct backtrace_frame_data_t {
  size_t num;             // The current fame number.
  uintptr_t pc;           // The absolute pc.
  uintptr_t sp;           // The top of the stack.
  size_t stack_size;      // The size of the stack, zero indicate an unknown stack size.
  backtrace_map_t map;    // The map associated with the given pc.
  std::string func_name;  // The function name associated with this pc, NULL if not found.
  uintptr_t func_offset;  // pc relative to the start of the function, only valid if func_name is not NULL.
};

#if defined(__APPLE__)
struct __darwin_ucontext;
typedef __darwin_ucontext ucontext_t;
#else
struct ucontext;
typedef ucontext ucontext_t;
#endif

struct backtrace_stackinfo_t {
  uint64_t start;
  uint64_t end;
  const uint8_t* data;
};

class Backtrace {
public:
  // Create the correct Backtrace object based on what is to be unwound.
  // If pid < 0 or equals the current pid, then the Backtrace object
  // corresponds to the current process.
  // If pid < 0 or equals the current pid and tid >= 0, then the Backtrace
  // object corresponds to a thread in the current process.
  // If pid >= 0 and tid < 0, then the Backtrace object corresponds to a
  // different process.
  // Tracing a thread in a different process is not supported.
  // If map is NULL, then create the map and manage it internally.
  // If map is not NULL, the map is still owned by the caller.
  static Backtrace* Create(pid_t pid, pid_t tid, BacktraceMap* map = NULL);

  // Create an offline Backtrace object that can be used to do an unwind without a process
  // that is still running. If cache_file is set to true, then elf information will be cached
  // for this call. The cached information survives until the calling process ends. This means
  // that subsequent calls to create offline Backtrace objects will continue to use the same
  // cache. It also assumes that the elf files used for each offline unwind are the same.
  static Backtrace* CreateOffline(pid_t pid, pid_t tid, BacktraceMap* map,
                                  const backtrace_stackinfo_t& stack, bool cache_file = false);

  virtual ~Backtrace();

  // Get the current stack trace and store in the backtrace_ structure.
  virtual bool Unwind(size_t num_ignore_frames, ucontext_t* context = NULL) = 0;

  // Get the function name and offset into the function given the pc.
  // If the string is empty, then no valid function name was found,
  // or the pc is not in any valid map.
  virtual std::string GetFunctionName(uintptr_t pc, uintptr_t* offset,
                                      const backtrace_map_t* map = NULL);

  // Fill in the map data associated with the given pc.
  virtual void FillInMap(uintptr_t pc, backtrace_map_t* map);

  // Read the data at a specific address.
  virtual bool ReadWord(uintptr_t ptr, word_t* out_value) = 0;

  // Read arbitrary data from a specific address. If a read request would
  // span from one map to another, this call only reads up until the end
  // of the current map.
  // Returns the total number of bytes actually read.
  virtual size_t Read(uintptr_t addr, uint8_t* buffer, size_t bytes) = 0;

  // Create a string representing the formatted line of backtrace information
  // for a single frame.
  virtual std::string FormatFrameData(size_t frame_num);
  virtual std::string FormatFrameData(const backtrace_frame_data_t* frame);

  pid_t Pid() const { return pid_; }
  pid_t Tid() const { return tid_; }
  size_t NumFrames() const { return frames_.size(); }

  const backtrace_frame_data_t* GetFrame(size_t frame_num) {
    if (frame_num >= frames_.size()) {
      return NULL;
    }
    return &frames_[frame_num];
  }

  typedef std::vector<backtrace_frame_data_t>::iterator iterator;
  iterator begin() { return frames_.begin(); }
  iterator end() { return frames_.end(); }

  typedef std::vector<backtrace_frame_data_t>::const_iterator const_iterator;
  const_iterator begin() const { return frames_.begin(); }
  const_iterator end() const { return frames_.end(); }

  BacktraceMap* GetMap() { return map_; }

  BacktraceUnwindError GetError() { return error_; }

  std::string GetErrorString(BacktraceUnwindError error);

protected:
  Backtrace(pid_t pid, pid_t tid, BacktraceMap* map);

  // The name returned is not demangled, GetFunctionName() takes care of
  // demangling the name.
  virtual std::string GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) = 0;

  virtual bool VerifyReadWordArgs(uintptr_t ptr, word_t* out_value);

  bool BuildMap();

  pid_t pid_;
  pid_t tid_;

  BacktraceMap* map_;
  bool map_shared_;

  std::vector<backtrace_frame_data_t> frames_;

  BacktraceUnwindError error_;
};

#endif // _BACKTRACE_BACKTRACE_H