1 /*
2 * Copyright (C) 2018 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <pthread.h>
30 #include <stdint.h>
31
32 #include <memory>
33 #include <string>
34 #include <vector>
35
36 #include <unwindstack/Elf.h>
37 #include <unwindstack/LocalUnwinder.h>
38 #include <unwindstack/MapInfo.h>
39 #include <unwindstack/Maps.h>
40 #include <unwindstack/Memory.h>
41 #include <unwindstack/Regs.h>
42 #include <unwindstack/RegsGetLocal.h>
43
44 namespace unwindstack {
45
Init()46 bool LocalUnwinder::Init() {
47 pthread_rwlock_init(&maps_rwlock_, nullptr);
48
49 // Create the maps.
50 maps_.reset(new unwindstack::LocalUpdatableMaps());
51 if (!maps_->Parse()) {
52 maps_.reset();
53 return false;
54 }
55
56 process_memory_ = unwindstack::Memory::CreateProcessMemory(getpid());
57
58 return true;
59 }
60
ShouldSkipLibrary(const std::string & map_name)61 bool LocalUnwinder::ShouldSkipLibrary(const std::string& map_name) {
62 for (const std::string& skip_library : skip_libraries_) {
63 if (skip_library == map_name) {
64 return true;
65 }
66 }
67 return false;
68 }
69
GetMapInfo(uint64_t pc)70 MapInfo* LocalUnwinder::GetMapInfo(uint64_t pc) {
71 pthread_rwlock_rdlock(&maps_rwlock_);
72 MapInfo* map_info = maps_->Find(pc);
73 pthread_rwlock_unlock(&maps_rwlock_);
74
75 if (map_info == nullptr) {
76 pthread_rwlock_wrlock(&maps_rwlock_);
77 // This is guaranteed not to invalidate any previous MapInfo objects so
78 // we don't need to worry about any MapInfo* values already in use.
79 if (maps_->Reparse()) {
80 map_info = maps_->Find(pc);
81 }
82 pthread_rwlock_unlock(&maps_rwlock_);
83 }
84
85 return map_info;
86 }
87
Unwind(std::vector<LocalFrameData> * frame_info,size_t max_frames)88 bool LocalUnwinder::Unwind(std::vector<LocalFrameData>* frame_info, size_t max_frames) {
89 std::unique_ptr<unwindstack::Regs> regs(unwindstack::Regs::CreateFromLocal());
90 unwindstack::RegsGetLocal(regs.get());
91 ArchEnum arch = regs->Arch();
92
93 size_t num_frames = 0;
94 bool adjust_pc = false;
95 while (true) {
96 uint64_t cur_pc = regs->pc();
97 uint64_t cur_sp = regs->sp();
98
99 MapInfo* map_info = GetMapInfo(cur_pc);
100 if (map_info == nullptr) {
101 break;
102 }
103
104 Elf* elf = map_info->GetElf(process_memory_, arch);
105 uint64_t rel_pc = elf->GetRelPc(cur_pc, map_info);
106 uint64_t step_pc = rel_pc;
107 uint64_t pc_adjustment;
108 if (adjust_pc) {
109 pc_adjustment = GetPcAdjustment(rel_pc, elf, arch);
110 } else {
111 pc_adjustment = 0;
112 }
113 step_pc -= pc_adjustment;
114
115 bool finished = false;
116 if (elf->StepIfSignalHandler(rel_pc, regs.get(), process_memory_.get())) {
117 step_pc = rel_pc;
118 } else if (!elf->Step(step_pc, regs.get(), process_memory_.get(), &finished)) {
119 finished = true;
120 }
121
122 // Skip any locations that are within this library.
123 if (num_frames != 0 || !ShouldSkipLibrary(map_info->name)) {
124 // Add frame information.
125 std::string func_name;
126 uint64_t func_offset;
127 if (elf->GetFunctionName(rel_pc, &func_name, &func_offset)) {
128 frame_info->emplace_back(map_info, cur_pc - pc_adjustment, rel_pc - pc_adjustment,
129 func_name, func_offset);
130 } else {
131 frame_info->emplace_back(map_info, cur_pc - pc_adjustment, rel_pc - pc_adjustment, "", 0);
132 }
133 num_frames++;
134 }
135
136 if (finished || frame_info->size() == max_frames ||
137 (cur_pc == regs->pc() && cur_sp == regs->sp())) {
138 break;
139 }
140 adjust_pc = true;
141 }
142 return num_frames != 0;
143 }
144
145 } // namespace unwindstack
146