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 <android-base/stringprintf.h>
26
27#include <backtrace/Backtrace.h>
28#include <backtrace/BacktraceMap.h>
29
30#include <demangle.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
57std::string Backtrace::GetFunctionName(uintptr_t pc, uintptr_t* offset, const backtrace_map_t* map) {
58  backtrace_map_t map_value;
59  if (map == nullptr) {
60    FillInMap(pc, &map_value);
61    map = &map_value;
62  }
63  // If no map is found, or this map is backed by a device, then return nothing.
64  if (map->start == 0 || (map->flags & PROT_DEVICE_MAP)) {
65    return "";
66  }
67  return demangle(GetFunctionNameRaw(pc, offset).c_str());
68}
69
70bool Backtrace::VerifyReadWordArgs(uintptr_t ptr, word_t* out_value) {
71  if (ptr & (sizeof(word_t)-1)) {
72    BACK_LOGW("invalid pointer %p", reinterpret_cast<void*>(ptr));
73    *out_value = static_cast<word_t>(-1);
74    return false;
75  }
76  return true;
77}
78
79std::string Backtrace::FormatFrameData(size_t frame_num) {
80  if (frame_num >= frames_.size()) {
81    return "";
82  }
83  return FormatFrameData(&frames_[frame_num]);
84}
85
86std::string Backtrace::FormatFrameData(const backtrace_frame_data_t* frame) {
87  std::string map_name;
88  if (BacktraceMap::IsValid(frame->map)) {
89    if (!frame->map.name.empty()) {
90      map_name = frame->map.name.c_str();
91      if (map_name[0] == '[' && map_name[map_name.size() - 1] == ']') {
92        map_name.resize(map_name.size() - 1);
93        map_name += StringPrintf(":%" PRIPTR "]", frame->map.start);
94      }
95    } else {
96      map_name = StringPrintf("<anonymous:%" PRIPTR ">", frame->map.start);
97    }
98  } else {
99    map_name = "<unknown>";
100  }
101
102  std::string line(StringPrintf("#%02zu pc %" PRIPTR "  ", frame->num, frame->rel_pc));
103  line += map_name;
104  // Special handling for non-zero offset maps, we need to print that
105  // information.
106  if (frame->map.offset != 0) {
107    line += " (offset " + StringPrintf("0x%" PRIxPTR, frame->map.offset) + ")";
108  }
109  if (!frame->func_name.empty()) {
110    line += " (" + frame->func_name;
111    if (frame->func_offset) {
112      line += StringPrintf("+%" PRIuPTR, frame->func_offset);
113    }
114    line += ')';
115  }
116
117  return line;
118}
119
120void Backtrace::FillInMap(uintptr_t pc, backtrace_map_t* map) {
121  if (map_ != nullptr) {
122    map_->FillIn(pc, map);
123  }
124}
125
126Backtrace* Backtrace::Create(pid_t pid, pid_t tid, BacktraceMap* map) {
127  if (pid == BACKTRACE_CURRENT_PROCESS) {
128    pid = getpid();
129    if (tid == BACKTRACE_CURRENT_THREAD) {
130      tid = gettid();
131    }
132  } else if (tid == BACKTRACE_CURRENT_THREAD) {
133    tid = pid;
134  }
135
136  if (pid == getpid()) {
137    return new UnwindCurrent(pid, tid, map);
138  } else {
139    return new UnwindPtrace(pid, tid, map);
140  }
141}
142
143std::string Backtrace::GetErrorString(BacktraceUnwindError error) {
144  switch (error) {
145  case BACKTRACE_UNWIND_NO_ERROR:
146    return "No error";
147  case BACKTRACE_UNWIND_ERROR_SETUP_FAILED:
148    return "Setup failed";
149  case BACKTRACE_UNWIND_ERROR_MAP_MISSING:
150    return "No map found";
151  case BACKTRACE_UNWIND_ERROR_INTERNAL:
152    return "Internal libbacktrace error, please submit a bugreport";
153  case BACKTRACE_UNWIND_ERROR_THREAD_DOESNT_EXIST:
154    return "Thread doesn't exist";
155  case BACKTRACE_UNWIND_ERROR_THREAD_TIMEOUT:
156    return "Thread has not responded to signal in time";
157  case BACKTRACE_UNWIND_ERROR_UNSUPPORTED_OPERATION:
158    return "Attempt to use an unsupported feature";
159  case BACKTRACE_UNWIND_ERROR_NO_CONTEXT:
160    return "Attempt to do an offline unwind without a context";
161  }
162}
163