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 <sys/types.h>
18 #include <ucontext.h>
19
20 #include <backtrace/Backtrace.h>
21 #include <backtrace/BacktraceMap.h>
22
23 #define UNW_LOCAL_ONLY
24 #include <libunwind.h>
25
26 #include "BacktraceLog.h"
27 #include "BacktraceThread.h"
28 #include "UnwindCurrent.h"
29 #include "UnwindMap.h"
30
31 //-------------------------------------------------------------------------
32 // UnwindCurrent functions.
33 //-------------------------------------------------------------------------
UnwindCurrent()34 UnwindCurrent::UnwindCurrent() {
35 }
36
~UnwindCurrent()37 UnwindCurrent::~UnwindCurrent() {
38 }
39
Unwind(size_t num_ignore_frames,ucontext_t * ucontext)40 bool UnwindCurrent::Unwind(size_t num_ignore_frames, ucontext_t* ucontext) {
41 if (!ucontext) {
42 int ret = unw_getcontext(&context_);
43 if (ret < 0) {
44 BACK_LOGW("unw_getcontext failed %d", ret);
45 return false;
46 }
47 }
48 else {
49 GetUnwContextFromUcontext(ucontext);
50 }
51 return UnwindFromContext(num_ignore_frames, false);
52 }
53
GetUnwContextFromUcontext(const ucontext_t * ucontext)54 void UnwindCurrent::GetUnwContextFromUcontext(const ucontext_t* ucontext) {
55 unw_tdep_context_t* unw_context = reinterpret_cast<unw_tdep_context_t*>(&context_);
56
57 #if defined(__arm__)
58 unw_context->regs[0] = ucontext->uc_mcontext.arm_r0;
59 unw_context->regs[1] = ucontext->uc_mcontext.arm_r1;
60 unw_context->regs[2] = ucontext->uc_mcontext.arm_r2;
61 unw_context->regs[3] = ucontext->uc_mcontext.arm_r3;
62 unw_context->regs[4] = ucontext->uc_mcontext.arm_r4;
63 unw_context->regs[5] = ucontext->uc_mcontext.arm_r5;
64 unw_context->regs[6] = ucontext->uc_mcontext.arm_r6;
65 unw_context->regs[7] = ucontext->uc_mcontext.arm_r7;
66 unw_context->regs[8] = ucontext->uc_mcontext.arm_r8;
67 unw_context->regs[9] = ucontext->uc_mcontext.arm_r9;
68 unw_context->regs[10] = ucontext->uc_mcontext.arm_r10;
69 unw_context->regs[11] = ucontext->uc_mcontext.arm_fp;
70 unw_context->regs[12] = ucontext->uc_mcontext.arm_ip;
71 unw_context->regs[13] = ucontext->uc_mcontext.arm_sp;
72 unw_context->regs[14] = ucontext->uc_mcontext.arm_lr;
73 unw_context->regs[15] = ucontext->uc_mcontext.arm_pc;
74 #else
75 unw_context->uc_mcontext = ucontext->uc_mcontext;
76 #endif
77 }
78
GetFunctionNameRaw(uintptr_t pc,uintptr_t * offset)79 std::string UnwindCurrent::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) {
80 *offset = 0;
81 char buf[512];
82 unw_word_t value;
83 if (unw_get_proc_name_by_ip(unw_local_addr_space, pc, buf, sizeof(buf),
84 &value, &context_) >= 0 && buf[0] != '\0') {
85 *offset = static_cast<uintptr_t>(value);
86 return buf;
87 }
88 return "";
89 }
90
UnwindFromContext(size_t num_ignore_frames,bool within_handler)91 bool UnwindCurrent::UnwindFromContext(size_t num_ignore_frames, bool within_handler) {
92 // The cursor structure is pretty large, do not put it on the stack.
93 unw_cursor_t* cursor = new unw_cursor_t;
94 int ret = unw_init_local(cursor, &context_);
95 if (ret < 0) {
96 if (!within_handler) {
97 BACK_LOGW("unw_init_local failed %d", ret);
98 }
99 delete cursor;
100 return false;
101 }
102
103 std::vector<backtrace_frame_data_t>* frames = GetFrames();
104 frames->reserve(MAX_BACKTRACE_FRAMES);
105 size_t num_frames = 0;
106 do {
107 unw_word_t pc;
108 ret = unw_get_reg(cursor, UNW_REG_IP, &pc);
109 if (ret < 0) {
110 if (!within_handler) {
111 BACK_LOGW("Failed to read IP %d", ret);
112 }
113 break;
114 }
115 unw_word_t sp;
116 ret = unw_get_reg(cursor, UNW_REG_SP, &sp);
117 if (ret < 0) {
118 if (!within_handler) {
119 BACK_LOGW("Failed to read SP %d", ret);
120 }
121 break;
122 }
123
124 if (num_ignore_frames == 0) {
125 frames->resize(num_frames+1);
126 backtrace_frame_data_t* frame = &frames->at(num_frames);
127 frame->num = num_frames;
128 frame->pc = static_cast<uintptr_t>(pc);
129 frame->sp = static_cast<uintptr_t>(sp);
130 frame->stack_size = 0;
131
132 if (num_frames > 0) {
133 // Set the stack size for the previous frame.
134 backtrace_frame_data_t* prev = &frames->at(num_frames-1);
135 prev->stack_size = frame->sp - prev->sp;
136 }
137
138 if (!within_handler) {
139 frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);
140 frame->map = FindMap(frame->pc);
141 } else {
142 frame->map = NULL;
143 frame->func_offset = 0;
144 }
145 num_frames++;
146 } else {
147 num_ignore_frames--;
148 }
149 ret = unw_step (cursor);
150 } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
151
152 delete cursor;
153 return true;
154 }
155
156 //-------------------------------------------------------------------------
157 // C++ object creation function.
158 //-------------------------------------------------------------------------
CreateCurrentObj(BacktraceMap * map)159 Backtrace* CreateCurrentObj(BacktraceMap* map) {
160 return new BacktraceCurrent(new UnwindCurrent(), map);
161 }
162
CreateThreadObj(pid_t tid,BacktraceMap * map)163 Backtrace* CreateThreadObj(pid_t tid, BacktraceMap* map) {
164 return new BacktraceThread(new UnwindCurrent(), tid, map);
165 }
166