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#include <inttypes.h>
18#include <stdint.h>
19#include <stdlib.h>
20#include <sys/types.h>
21#include <ucontext.h>
22
23#include <string>
24
25#include <base/stringprintf.h>
26
27#include <backtrace/Backtrace.h>
28#include <backtrace/BacktraceMap.h>
29
30#include <cutils/threads.h>
31
32#include "BacktraceLog.h"
33#include "thread_utils.h"
34#include "UnwindCurrent.h"
35#include "UnwindPtrace.h"
36
37using android::base::StringPrintf;
38
39//-------------------------------------------------------------------------
40// Backtrace functions.
41//-------------------------------------------------------------------------
42Backtrace::Backtrace(pid_t pid, pid_t tid, BacktraceMap* map)
43    : pid_(pid), tid_(tid), map_(map), map_shared_(true) {
44  if (map_ == nullptr) {
45    map_ = BacktraceMap::Create(pid);
46    map_shared_ = false;
47  }
48}
49
50Backtrace::~Backtrace() {
51  if (map_ && !map_shared_) {
52    delete map_;
53    map_ = nullptr;
54  }
55}
56
57extern "C" char* __cxa_demangle(const char* mangled, char* buf, size_t* len,
58                                int* status);
59
60std::string Backtrace::GetFunctionName(uintptr_t pc, uintptr_t* offset) {
61  std::string func_name = GetFunctionNameRaw(pc, offset);
62  if (!func_name.empty()) {
63#if defined(__APPLE__)
64    // Mac OS' __cxa_demangle demangles "f" as "float"; last tested on 10.7.
65    if (func_name[0] != '_') {
66      return func_name;
67    }
68#endif
69    char* name = __cxa_demangle(func_name.c_str(), 0, 0, 0);
70    if (name) {
71      func_name = name;
72      free(name);
73    }
74  }
75  return func_name;
76}
77
78bool Backtrace::VerifyReadWordArgs(uintptr_t ptr, word_t* out_value) {
79  if (ptr & (sizeof(word_t)-1)) {
80    BACK_LOGW("invalid pointer %p", reinterpret_cast<void*>(ptr));
81    *out_value = static_cast<word_t>(-1);
82    return false;
83  }
84  return true;
85}
86
87std::string Backtrace::FormatFrameData(size_t frame_num) {
88  if (frame_num >= frames_.size()) {
89    return "";
90  }
91  return FormatFrameData(&frames_[frame_num]);
92}
93
94std::string Backtrace::FormatFrameData(const backtrace_frame_data_t* frame) {
95  const char* map_name;
96  if (BacktraceMap::IsValid(frame->map) && !frame->map.name.empty()) {
97    map_name = frame->map.name.c_str();
98  } else {
99    map_name = "<unknown>";
100  }
101
102  uintptr_t relative_pc = BacktraceMap::GetRelativePc(frame->map, frame->pc);
103
104  std::string line(StringPrintf("#%02zu pc %" PRIPTR "  %s", frame->num, relative_pc, map_name));
105  // Special handling for non-zero offset maps, we need to print that
106  // information.
107  if (frame->map.offset != 0) {
108    line += " (offset " + StringPrintf("0x%" PRIxPTR, frame->map.offset) + ")";
109  }
110  if (!frame->func_name.empty()) {
111    line += " (" + frame->func_name;
112    if (frame->func_offset) {
113      line += StringPrintf("+%" PRIuPTR, frame->func_offset);
114    }
115    line += ')';
116  }
117
118  return line;
119}
120
121void Backtrace::FillInMap(uintptr_t pc, backtrace_map_t* map) {
122  if (map_ != nullptr) {
123    map_->FillIn(pc, map);
124  }
125}
126
127Backtrace* Backtrace::Create(pid_t pid, pid_t tid, BacktraceMap* map) {
128  if (pid == BACKTRACE_CURRENT_PROCESS) {
129    pid = getpid();
130    if (tid == BACKTRACE_CURRENT_THREAD) {
131      tid = gettid();
132    }
133  } else if (tid == BACKTRACE_CURRENT_THREAD) {
134    tid = pid;
135  }
136
137  if (pid == getpid()) {
138    return new UnwindCurrent(pid, tid, map);
139  } else {
140    return new UnwindPtrace(pid, tid, map);
141  }
142}
143