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 #include <android-base/threads.h>
27
28 #include <backtrace/Backtrace.h>
29 #include <backtrace/BacktraceMap.h>
30
31 #include <demangle.h>
32
33 #include "BacktraceLog.h"
34 #include "UnwindStack.h"
35
36 using android::base::StringPrintf;
37
38 //-------------------------------------------------------------------------
39 // Backtrace functions.
40 //-------------------------------------------------------------------------
Backtrace(pid_t pid,pid_t tid,BacktraceMap * map)41 Backtrace::Backtrace(pid_t pid, pid_t tid, BacktraceMap* map)
42 : pid_(pid), tid_(tid), map_(map), map_shared_(true) {
43 if (map_ == nullptr) {
44 map_ = BacktraceMap::Create(pid);
45 map_shared_ = false;
46 }
47 }
48
~Backtrace()49 Backtrace::~Backtrace() {
50 if (map_ && !map_shared_) {
51 delete map_;
52 map_ = nullptr;
53 }
54 }
55
GetFunctionName(uint64_t pc,uint64_t * offset,const backtrace_map_t * map)56 std::string Backtrace::GetFunctionName(uint64_t pc, uint64_t* offset, const backtrace_map_t* map) {
57 backtrace_map_t map_value;
58 if (map == nullptr) {
59 FillInMap(pc, &map_value);
60 map = &map_value;
61 }
62 // If no map is found, or this map is backed by a device, then return nothing.
63 if (map->start == 0 || (map->flags & PROT_DEVICE_MAP)) {
64 return "";
65 }
66 return demangle(GetFunctionNameRaw(pc, offset).c_str());
67 }
68
VerifyReadWordArgs(uint64_t ptr,word_t * out_value)69 bool Backtrace::VerifyReadWordArgs(uint64_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 std::string map_name;
87 if (BacktraceMap::IsValid(frame->map)) {
88 map_name = frame->map.Name();
89 if (!frame->map.name.empty()) {
90 if (map_name[0] == '[' && map_name[map_name.size() - 1] == ']') {
91 map_name.resize(map_name.size() - 1);
92 map_name += StringPrintf(":%" PRIPTR "]", frame->map.start);
93 }
94 }
95 } else {
96 map_name = "<unknown>";
97 }
98
99 std::string line(StringPrintf("#%02zu pc %" PRIPTR " ", frame->num, frame->rel_pc));
100 line += map_name;
101 // Special handling for non-zero offset maps, we need to print that
102 // information.
103 if (frame->map.offset != 0) {
104 line += " (offset " + StringPrintf("0x%" PRIx64, frame->map.offset) + ")";
105 }
106 if (!frame->func_name.empty()) {
107 line += " (" + frame->func_name;
108 if (frame->func_offset) {
109 line += StringPrintf("+%" PRIu64, frame->func_offset);
110 }
111 line += ')';
112 }
113
114 return line;
115 }
116
FillInMap(uint64_t pc,backtrace_map_t * map)117 void Backtrace::FillInMap(uint64_t pc, backtrace_map_t* map) {
118 if (map_ != nullptr) {
119 map_->FillIn(pc, map);
120 }
121 }
122
Create(pid_t pid,pid_t tid,BacktraceMap * map)123 Backtrace* Backtrace::Create(pid_t pid, pid_t tid, BacktraceMap* map) {
124 if (pid == BACKTRACE_CURRENT_PROCESS) {
125 pid = getpid();
126 if (tid == BACKTRACE_CURRENT_THREAD) {
127 tid = android::base::GetThreadId();
128 }
129 } else if (tid == BACKTRACE_CURRENT_THREAD) {
130 tid = pid;
131 }
132
133 if (pid == getpid()) {
134 return new UnwindStackCurrent(pid, tid, map);
135 } else {
136 return new UnwindStackPtrace(pid, tid, map);
137 }
138 }
139
GetErrorString(BacktraceUnwindError error)140 std::string Backtrace::GetErrorString(BacktraceUnwindError error) {
141 switch (error.error_code) {
142 case BACKTRACE_UNWIND_NO_ERROR:
143 return "No error";
144 case BACKTRACE_UNWIND_ERROR_SETUP_FAILED:
145 return "Setup failed";
146 case BACKTRACE_UNWIND_ERROR_MAP_MISSING:
147 return "No map found";
148 case BACKTRACE_UNWIND_ERROR_INTERNAL:
149 return "Internal libbacktrace error, please submit a bugreport";
150 case BACKTRACE_UNWIND_ERROR_THREAD_DOESNT_EXIST:
151 return "Thread doesn't exist";
152 case BACKTRACE_UNWIND_ERROR_THREAD_TIMEOUT:
153 return "Thread has not responded to signal in time";
154 case BACKTRACE_UNWIND_ERROR_UNSUPPORTED_OPERATION:
155 return "Attempt to use an unsupported feature";
156 case BACKTRACE_UNWIND_ERROR_NO_CONTEXT:
157 return "Attempt to do an offline unwind without a context";
158 case BACKTRACE_UNWIND_ERROR_EXCEED_MAX_FRAMES_LIMIT:
159 return "Exceed MAX_BACKTRACE_FRAMES limit";
160 case BACKTRACE_UNWIND_ERROR_ACCESS_MEM_FAILED:
161 return android::base::StringPrintf("Failed to read memory at addr 0x%" PRIx64,
162 error.error_info.addr);
163 case BACKTRACE_UNWIND_ERROR_ACCESS_REG_FAILED:
164 return android::base::StringPrintf("Failed to read register %" PRIu64, error.error_info.regno);
165 case BACKTRACE_UNWIND_ERROR_FIND_PROC_INFO_FAILED:
166 return "Failed to find a function in debug sections";
167 case BACKTRACE_UNWIND_ERROR_EXECUTE_DWARF_INSTRUCTION_FAILED:
168 return "Failed to execute dwarf instructions in debug sections";
169 case BACKTRACE_UNWIND_ERROR_UNWIND_INFO:
170 return "Failed to unwind due to invalid unwind information";
171 case BACKTRACE_UNWIND_ERROR_REPEATED_FRAME:
172 return "Failed to unwind due to same sp/pc repeating";
173 case BACKTRACE_UNWIND_ERROR_INVALID_ELF:
174 return "Failed to unwind due to invalid elf";
175 }
176 }
177