UnwindCurrent.cpp revision 17224d57fbc690051fbfecdc95140ead21305ba3 
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/ucontext.h>
18#include <sys/types.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 "UnwindCurrent.h"
28#include "UnwindMap.h"
29
30//-------------------------------------------------------------------------
31// UnwindCurrent functions.
32//-------------------------------------------------------------------------
33UnwindCurrent::UnwindCurrent() {
34}
35
36UnwindCurrent::~UnwindCurrent() {
37}
38
39bool UnwindCurrent::Unwind(size_t num_ignore_frames) {
40  int ret = unw_getcontext(&context_);
41  if (ret < 0) {
42    BACK_LOGW("unw_getcontext failed %d", ret);
43    return false;
44  }
45  return UnwindFromContext(num_ignore_frames, false);
46}
47
48std::string UnwindCurrent::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) {
49  *offset = 0;
50  char buf[512];
51  unw_word_t value;
52  if (unw_get_proc_name_by_ip(unw_local_addr_space, pc, buf, sizeof(buf),
53                              &value, &context_) >= 0 && buf[0] != '\0') {
54    *offset = static_cast<uintptr_t>(value);
55    return buf;
56  }
57  return "";
58}
59
60bool UnwindCurrent::UnwindFromContext(size_t num_ignore_frames, bool within_handler) {
61  // The cursor structure is pretty large, do not put it on the stack.
62  unw_cursor_t* cursor = new unw_cursor_t;
63  int ret = unw_init_local(cursor, &context_);
64  if (ret < 0) {
65    if (!within_handler) {
66      BACK_LOGW("unw_init_local failed %d", ret);
67    }
68    delete cursor;
69    return false;
70  }
71
72  std::vector<backtrace_frame_data_t>* frames = GetFrames();
73  frames->reserve(MAX_BACKTRACE_FRAMES);
74  size_t num_frames = 0;
75  do {
76    unw_word_t pc;
77    ret = unw_get_reg(cursor, UNW_REG_IP, &pc);
78    if (ret < 0) {
79      if (!within_handler) {
80        BACK_LOGW("Failed to read IP %d", ret);
81      }
82      break;
83    }
84    unw_word_t sp;
85    ret = unw_get_reg(cursor, UNW_REG_SP, &sp);
86    if (ret < 0) {
87      if (!within_handler) {
88        BACK_LOGW("Failed to read SP %d", ret);
89      }
90      break;
91    }
92
93    if (num_ignore_frames == 0) {
94      frames->resize(num_frames+1);
95      backtrace_frame_data_t* frame = &frames->at(num_frames);
96      frame->num = num_frames;
97      frame->pc = static_cast<uintptr_t>(pc);
98      frame->sp = static_cast<uintptr_t>(sp);
99      frame->stack_size = 0;
100
101      if (num_frames > 0) {
102        // Set the stack size for the previous frame.
103        backtrace_frame_data_t* prev = &frames->at(num_frames-1);
104        prev->stack_size = frame->sp - prev->sp;
105      }
106
107      if (!within_handler) {
108        frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);
109        frame->map = FindMap(frame->pc);
110      } else {
111        frame->map = NULL;
112        frame->func_offset = 0;
113      }
114      num_frames++;
115    } else {
116      num_ignore_frames--;
117    }
118    ret = unw_step (cursor);
119  } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
120
121  delete cursor;
122  return true;
123}
124
125void UnwindCurrent::ExtractContext(void* sigcontext) {
126  unw_tdep_context_t* context = reinterpret_cast<unw_tdep_context_t*>(&context_);
127  const ucontext_t* uc = reinterpret_cast<const ucontext_t*>(sigcontext);
128
129#if defined(__arm__)
130  context->regs[0] = uc->uc_mcontext.arm_r0;
131  context->regs[1] = uc->uc_mcontext.arm_r1;
132  context->regs[2] = uc->uc_mcontext.arm_r2;
133  context->regs[3] = uc->uc_mcontext.arm_r3;
134  context->regs[4] = uc->uc_mcontext.arm_r4;
135  context->regs[5] = uc->uc_mcontext.arm_r5;
136  context->regs[6] = uc->uc_mcontext.arm_r6;
137  context->regs[7] = uc->uc_mcontext.arm_r7;
138  context->regs[8] = uc->uc_mcontext.arm_r8;
139  context->regs[9] = uc->uc_mcontext.arm_r9;
140  context->regs[10] = uc->uc_mcontext.arm_r10;
141  context->regs[11] = uc->uc_mcontext.arm_fp;
142  context->regs[12] = uc->uc_mcontext.arm_ip;
143  context->regs[13] = uc->uc_mcontext.arm_sp;
144  context->regs[14] = uc->uc_mcontext.arm_lr;
145  context->regs[15] = uc->uc_mcontext.arm_pc;
146#else
147  context->uc_mcontext = uc->uc_mcontext;
148#endif
149}
150
151//-------------------------------------------------------------------------
152// UnwindThread functions.
153//-------------------------------------------------------------------------
154UnwindThread::UnwindThread() {
155}
156
157UnwindThread::~UnwindThread() {
158}
159
160void UnwindThread::ThreadUnwind(
161    siginfo_t* /*siginfo*/, void* sigcontext, size_t num_ignore_frames) {
162  ExtractContext(sigcontext);
163  UnwindFromContext(num_ignore_frames, true);
164}
165
166//-------------------------------------------------------------------------
167// C++ object creation function.
168//-------------------------------------------------------------------------
169Backtrace* CreateCurrentObj(BacktraceMap* map) {
170  return new BacktraceCurrent(new UnwindCurrent(), map);
171}
172
173Backtrace* CreateThreadObj(pid_t tid, BacktraceMap* map) {
174  UnwindThread* thread_obj = new UnwindThread();
175  return new BacktraceThread(thread_obj, thread_obj, tid, map);
176}
177