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
37 using android::base::StringPrintf;
38
39 //-------------------------------------------------------------------------
40 // Backtrace functions.
41 //-------------------------------------------------------------------------
Backtrace(pid_t pid,pid_t tid,BacktraceMap * map)42 Backtrace::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
~Backtrace()50 Backtrace::~Backtrace() {
51 if (map_ && !map_shared_) {
52 delete map_;
53 map_ = nullptr;
54 }
55 }
56
GetFunctionName(uintptr_t pc,uintptr_t * offset,const backtrace_map_t * map)57 std::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
VerifyReadWordArgs(uintptr_t ptr,word_t * out_value)70 bool 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
FormatFrameData(size_t frame_num)79 std::string Backtrace::FormatFrameData(size_t frame_num) {
80 if (frame_num >= frames_.size()) {
81 return "";
82 }
83 return FormatFrameData(&frames_[frame_num]);
84 }
85
FormatFrameData(const backtrace_frame_data_t * frame)86 std::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
FillInMap(uintptr_t pc,backtrace_map_t * map)120 void Backtrace::FillInMap(uintptr_t pc, backtrace_map_t* map) {
121 if (map_ != nullptr) {
122 map_->FillIn(pc, map);
123 }
124 }
125
Create(pid_t pid,pid_t tid,BacktraceMap * map)126 Backtrace* 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
GetErrorString(BacktraceUnwindError error)143 std::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