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 "BacktraceLog.h"
31 #include "thread_utils.h"
32 #include "UnwindCurrent.h"
33 #include "UnwindPtrace.h"
34
35 using android::base::StringPrintf;
36
37 //-------------------------------------------------------------------------
38 // Backtrace functions.
39 //-------------------------------------------------------------------------
Backtrace(pid_t pid,pid_t tid,BacktraceMap * map)40 Backtrace::Backtrace(pid_t pid, pid_t tid, BacktraceMap* map)
41 : pid_(pid), tid_(tid), map_(map), map_shared_(true) {
42 if (map_ == nullptr) {
43 map_ = BacktraceMap::Create(pid);
44 map_shared_ = false;
45 }
46 }
47
~Backtrace()48 Backtrace::~Backtrace() {
49 if (map_ && !map_shared_) {
50 delete map_;
51 map_ = nullptr;
52 }
53 }
54
GetFunctionName(uintptr_t pc,uintptr_t * offset,const backtrace_map_t * map)55 std::string Backtrace::GetFunctionName(uintptr_t pc, uintptr_t* offset, const backtrace_map_t* map) {
56 backtrace_map_t map_value;
57 if (map == nullptr) {
58 FillInMap(pc, &map_value);
59 map = &map_value;
60 }
61 // If no map is found, or this map is backed by a device, then return nothing.
62 if (map->start == 0 || (map->flags & PROT_DEVICE_MAP)) {
63 return "";
64 }
65 std::string func_name = GetFunctionNameRaw(pc, offset);
66 return func_name;
67 }
68
VerifyReadWordArgs(uintptr_t ptr,word_t * out_value)69 bool Backtrace::VerifyReadWordArgs(uintptr_t ptr, word_t* out_value) {
70 if (ptr & (sizeof(word_t)-1)) {
71 BACK_LOGW("invalid pointer %p", reinterpret_cast<void*>(ptr));
72 *out_value = static_cast<word_t>(-1);
73 return false;
74 }
75 return true;
76 }
77
FormatFrameData(size_t frame_num)78 std::string Backtrace::FormatFrameData(size_t frame_num) {
79 if (frame_num >= frames_.size()) {
80 return "";
81 }
82 return FormatFrameData(&frames_[frame_num]);
83 }
84
FormatFrameData(const backtrace_frame_data_t * frame)85 std::string Backtrace::FormatFrameData(const backtrace_frame_data_t* frame) {
86 uintptr_t relative_pc;
87 std::string map_name;
88 if (BacktraceMap::IsValid(frame->map)) {
89 relative_pc = BacktraceMap::GetRelativePc(frame->map, frame->pc);
90 if (!frame->map.name.empty()) {
91 map_name = frame->map.name.c_str();
92 if (map_name[0] == '[' && map_name[map_name.size() - 1] == ']') {
93 map_name.resize(map_name.size() - 1);
94 map_name += StringPrintf(":%" PRIPTR "]", frame->map.start);
95 }
96 } else {
97 map_name = StringPrintf("<anonymous:%" PRIPTR ">", frame->map.start);
98 }
99 } else {
100 map_name = "<unknown>";
101 relative_pc = frame->pc;
102 }
103
104 std::string line(StringPrintf("#%02zu pc %" PRIPTR " ", frame->num, relative_pc));
105 line += map_name;
106 // Special handling for non-zero offset maps, we need to print that
107 // information.
108 if (frame->map.offset != 0) {
109 line += " (offset " + StringPrintf("0x%" PRIxPTR, frame->map.offset) + ")";
110 }
111 if (!frame->func_name.empty()) {
112 line += " (" + frame->func_name;
113 if (frame->func_offset) {
114 line += StringPrintf("+%" PRIuPTR, frame->func_offset);
115 }
116 line += ')';
117 }
118
119 return line;
120 }
121
FillInMap(uintptr_t pc,backtrace_map_t * map)122 void Backtrace::FillInMap(uintptr_t pc, backtrace_map_t* map) {
123 if (map_ != nullptr) {
124 map_->FillIn(pc, map);
125 }
126 }
127
Create(pid_t pid,pid_t tid,BacktraceMap * map)128 Backtrace* Backtrace::Create(pid_t pid, pid_t tid, BacktraceMap* map) {
129 if (pid == BACKTRACE_CURRENT_PROCESS) {
130 pid = getpid();
131 if (tid == BACKTRACE_CURRENT_THREAD) {
132 tid = gettid();
133 }
134 } else if (tid == BACKTRACE_CURRENT_THREAD) {
135 tid = pid;
136 }
137
138 if (pid == getpid()) {
139 return new UnwindCurrent(pid, tid, map);
140 } else {
141 return new UnwindPtrace(pid, tid, map);
142 }
143 }
144
GetErrorString(BacktraceUnwindError error)145 std::string Backtrace::GetErrorString(BacktraceUnwindError error) {
146 switch (error) {
147 case BACKTRACE_UNWIND_NO_ERROR:
148 return "No error";
149 case BACKTRACE_UNWIND_ERROR_SETUP_FAILED:
150 return "Setup failed";
151 case BACKTRACE_UNWIND_ERROR_MAP_MISSING:
152 return "No map found";
153 case BACKTRACE_UNWIND_ERROR_INTERNAL:
154 return "Internal libbacktrace error, please submit a bugreport";
155 case BACKTRACE_UNWIND_ERROR_THREAD_DOESNT_EXIST:
156 return "Thread doesn't exist";
157 case BACKTRACE_UNWIND_ERROR_THREAD_TIMEOUT:
158 return "Thread has not responded to signal in time";
159 case BACKTRACE_UNWIND_ERROR_UNSUPPORTED_OPERATION:
160 return "Attempt to use an unsupported feature";
161 case BACKTRACE_UNWIND_ERROR_NO_CONTEXT:
162 return "Attempt to do an offline unwind without a context";
163 }
164 }
165