1/*
2 * Copyright (C) 2014 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_MAP_H
18#define _BACKTRACE_BACKTRACE_MAP_H
19
20#include <stdint.h>
21#include <sys/types.h>
22#ifdef _WIN32
23// MINGW does not define these constants.
24#define PROT_NONE 0
25#define PROT_READ 0x1
26#define PROT_WRITE 0x2
27#define PROT_EXEC 0x4
28#else
29#include <sys/mman.h>
30#endif
31
32#include <deque>
33#include <string>
34#include <vector>
35
36// Special flag to indicate a map is in /dev/. However, a map in
37// /dev/ashmem/... does not set this flag.
38static constexpr int PROT_DEVICE_MAP = 0x8000;
39
40struct backtrace_map_t {
41  uintptr_t start = 0;
42  uintptr_t end = 0;
43  uintptr_t offset = 0;
44  uintptr_t load_bias = 0;
45  int flags = 0;
46  std::string name;
47};
48
49class BacktraceMap {
50public:
51  // If uncached is true, then parse the current process map as of the call.
52  // Passing a map created with uncached set to true to Backtrace::Create()
53  // is unsupported.
54  static BacktraceMap* Create(pid_t pid, bool uncached = false);
55
56  static BacktraceMap* Create(pid_t pid, const std::vector<backtrace_map_t>& maps);
57
58  virtual ~BacktraceMap();
59
60  // Fill in the map data structure for the given address.
61  virtual void FillIn(uintptr_t addr, backtrace_map_t* map);
62
63  // The flags returned are the same flags as used by the mmap call.
64  // The values are PROT_*.
65  int GetFlags(uintptr_t pc) {
66    backtrace_map_t map;
67    FillIn(pc, &map);
68    if (IsValid(map)) {
69      return map.flags;
70    }
71    return PROT_NONE;
72  }
73
74  bool IsReadable(uintptr_t pc) { return GetFlags(pc) & PROT_READ; }
75  bool IsWritable(uintptr_t pc) { return GetFlags(pc) & PROT_WRITE; }
76  bool IsExecutable(uintptr_t pc) { return GetFlags(pc) & PROT_EXEC; }
77
78  // In order to use the iterators on this object, a caller must
79  // call the LockIterator and UnlockIterator function to guarantee
80  // that the data does not change while it's being used.
81  virtual void LockIterator() {}
82  virtual void UnlockIterator() {}
83
84  typedef std::deque<backtrace_map_t>::iterator iterator;
85  iterator begin() { return maps_.begin(); }
86  iterator end() { return maps_.end(); }
87
88  typedef std::deque<backtrace_map_t>::const_iterator const_iterator;
89  const_iterator begin() const { return maps_.begin(); }
90  const_iterator end() const { return maps_.end(); }
91
92  size_t size() const { return maps_.size(); }
93
94  virtual bool Build();
95
96  static inline bool IsValid(const backtrace_map_t& map) {
97    return map.end > 0;
98  }
99
100protected:
101  BacktraceMap(pid_t pid);
102
103  virtual bool ParseLine(const char* line, backtrace_map_t* map);
104
105  std::deque<backtrace_map_t> maps_;
106  pid_t pid_;
107};
108
109class ScopedBacktraceMapIteratorLock {
110public:
111  explicit ScopedBacktraceMapIteratorLock(BacktraceMap* map) : map_(map) {
112    map->LockIterator();
113  }
114
115  ~ScopedBacktraceMapIteratorLock() {
116    map_->UnlockIterator();
117  }
118
119private:
120  BacktraceMap* map_;
121};
122
123#endif // _BACKTRACE_BACKTRACE_MAP_H
124