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::CreateProcessMemoryThreadCached(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
Unwind(std::vector<LocalFrameData> * frame_info,size_t max_frames)70 bool LocalUnwinder::Unwind(std::vector<LocalFrameData>* frame_info, size_t max_frames) {
71 std::unique_ptr<unwindstack::Regs> regs(unwindstack::Regs::CreateFromLocal());
72 unwindstack::RegsGetLocal(regs.get());
73 ArchEnum arch = regs->Arch();
74
75 // Clear any cached data from previous unwinds.
76 process_memory_->Clear();
77
78 size_t num_frames = 0;
79 bool adjust_pc = false;
80 while (true) {
81 uint64_t cur_pc = regs->pc();
82 uint64_t cur_sp = regs->sp();
83
84 MapInfo* map_info = maps_->Find(cur_pc);
85 if (map_info == nullptr) {
86 break;
87 }
88
89 Elf* elf = map_info->GetElf(process_memory_, arch);
90 uint64_t rel_pc = elf->GetRelPc(cur_pc, map_info);
91 uint64_t step_pc = rel_pc;
92 uint64_t pc_adjustment;
93 if (adjust_pc) {
94 pc_adjustment = GetPcAdjustment(rel_pc, elf, arch);
95 } else {
96 pc_adjustment = 0;
97 }
98 step_pc -= pc_adjustment;
99
100 bool finished = false;
101 bool is_signal_frame = false;
102 if (elf->StepIfSignalHandler(rel_pc, regs.get(), process_memory_.get())) {
103 step_pc = rel_pc;
104 } else if (!elf->Step(step_pc, regs.get(), process_memory_.get(), &finished,
105 &is_signal_frame)) {
106 finished = true;
107 }
108
109 // Skip any locations that are within this library.
110 if (num_frames != 0 || !ShouldSkipLibrary(map_info->name())) {
111 // Add frame information.
112 SharedString func_name;
113 uint64_t func_offset;
114 if (elf->GetFunctionName(rel_pc, &func_name, &func_offset)) {
115 frame_info->emplace_back(map_info, cur_pc - pc_adjustment, rel_pc - pc_adjustment,
116 func_name, func_offset);
117 } else {
118 frame_info->emplace_back(map_info, cur_pc - pc_adjustment, rel_pc - pc_adjustment, "", 0);
119 }
120 num_frames++;
121 }
122
123 if (finished || frame_info->size() == max_frames ||
124 (cur_pc == regs->pc() && cur_sp == regs->sp())) {
125 break;
126 }
127 adjust_pc = true;
128 }
129 return num_frames != 0;
130 }
131
132 } // namespace unwindstack
133