UnwindCurrent.cpp revision 17e91d44edf5e6476a477a200bcd89d4327358a3 
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#define LOG_TAG "libbacktrace"
18
19#include <sys/types.h>
20
21#include <cutils/log.h>
22
23#include <backtrace/backtrace.h>
24
25#define UNW_LOCAL_ONLY
26#include <libunwind.h>
27
28#include "UnwindCurrent.h"
29
30#if defined(__arm__)
31  #if !defined(__BIONIC_HAVE_UCONTEXT_T)
32  // The Current version of the Android <signal.h> doesn't define ucontext_t.
33  #include <asm/sigcontext.h> // Ensure 'struct sigcontext' is defined.
34
35  // Machine context at the time a signal was raised.
36  typedef struct ucontext {
37    uint32_t uc_flags;
38    struct ucontext* uc_link;
39    stack_t uc_stack;
40    struct sigcontext uc_mcontext;
41    uint32_t uc_sigmask;
42  } ucontext_t;
43  #endif // !__BIONIC_HAVE_UCONTEXT_T
44#endif // defined(__arm__)
45
46//-------------------------------------------------------------------------
47// UnwindCurrent functions.
48//-------------------------------------------------------------------------
49UnwindCurrent::UnwindCurrent() {
50}
51
52UnwindCurrent::~UnwindCurrent() {
53}
54
55bool UnwindCurrent::Unwind(size_t num_ignore_frames) {
56  int ret = unw_getcontext(&context_);
57  if (ret < 0) {
58    ALOGW("UnwindCurrent::Unwind: unw_getcontext failed %d\n", ret);
59    return false;
60  }
61  return UnwindFromContext(num_ignore_frames, true);
62}
63
64std::string UnwindCurrent::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) {
65  *offset = 0;
66  char buf[512];
67  unw_word_t value;
68  if (unw_get_proc_name_by_ip(unw_local_addr_space, pc, buf, sizeof(buf),
69                              &value, &context_) >= 0 && buf[0] != '\0') {
70    *offset = static_cast<uintptr_t>(value);
71    return buf;
72  }
73  return "";
74}
75
76bool UnwindCurrent::UnwindFromContext(size_t num_ignore_frames, bool resolve) {
77  backtrace_t* backtrace = GetBacktraceData();
78  backtrace->num_frames = 0;
79
80  // The cursor structure is pretty large, do not put it on the stack.
81  unw_cursor_t* cursor = new unw_cursor_t;
82  int ret = unw_init_local(cursor, &context_);
83  if (ret < 0) {
84    ALOGW("UnwindCurrent::UnwindWithContext: unw_init_local failed %d\n", ret);
85    return false;
86  }
87
88  do {
89    unw_word_t pc;
90    ret = unw_get_reg(cursor, UNW_REG_IP, &pc);
91    if (ret < 0) {
92      ALOGW("UnwindCurrent::UnwindWithContext: Failed to read IP %d\n", ret);
93      break;
94    }
95    unw_word_t sp;
96    ret = unw_get_reg(cursor, UNW_REG_SP, &sp);
97    if (ret < 0) {
98      ALOGW("UnwindCurrent::UnwindWithContext: Failed to read SP %d\n", ret);
99      break;
100    }
101
102    if (num_ignore_frames == 0) {
103      size_t num_frames = backtrace->num_frames;
104      backtrace_frame_data_t* frame = &backtrace->frames[num_frames];
105      frame->pc = static_cast<uintptr_t>(pc);
106      frame->sp = static_cast<uintptr_t>(sp);
107      frame->stack_size = 0;
108      frame->map_name = NULL;
109      frame->map_offset = 0;
110      frame->func_name = NULL;
111      frame->func_offset = 0;
112
113      if (num_frames > 0) {
114        // Set the stack size for the previous frame.
115        backtrace_frame_data_t* prev = &backtrace->frames[num_frames-1];
116        prev->stack_size = frame->sp - prev->sp;
117      }
118
119      if (resolve) {
120        std::string func_name = backtrace_obj_->GetFunctionName(frame->pc, &frame->func_offset);
121        if (!func_name.empty()) {
122          frame->func_name = strdup(func_name.c_str());
123        }
124
125        uintptr_t map_start;
126        frame->map_name = backtrace_obj_->GetMapName(frame->pc, &map_start);
127        if (frame->map_name) {
128          frame->map_offset = frame->pc - map_start;
129        }
130      }
131
132      backtrace->num_frames++;
133    } else {
134      num_ignore_frames--;
135    }
136    ret = unw_step (cursor);
137  } while (ret > 0 && backtrace->num_frames < MAX_BACKTRACE_FRAMES);
138
139  delete cursor;
140  return true;
141}
142
143void UnwindCurrent::ExtractContext(void* sigcontext) {
144  unw_tdep_context_t* context = reinterpret_cast<unw_tdep_context_t*>(&context_);
145
146#if defined(__arm__)
147  const ucontext_t* uc = reinterpret_cast<const ucontext_t*>(sigcontext);
148
149  context->regs[0] = uc->uc_mcontext.arm_r0;
150  context->regs[1] = uc->uc_mcontext.arm_r1;
151  context->regs[2] = uc->uc_mcontext.arm_r2;
152  context->regs[3] = uc->uc_mcontext.arm_r3;
153  context->regs[4] = uc->uc_mcontext.arm_r4;
154  context->regs[5] = uc->uc_mcontext.arm_r5;
155  context->regs[6] = uc->uc_mcontext.arm_r6;
156  context->regs[7] = uc->uc_mcontext.arm_r7;
157  context->regs[8] = uc->uc_mcontext.arm_r8;
158  context->regs[9] = uc->uc_mcontext.arm_r9;
159  context->regs[10] = uc->uc_mcontext.arm_r10;
160  context->regs[11] = uc->uc_mcontext.arm_fp;
161  context->regs[12] = uc->uc_mcontext.arm_ip;
162  context->regs[13] = uc->uc_mcontext.arm_sp;
163  context->regs[14] = uc->uc_mcontext.arm_lr;
164  context->regs[15] = uc->uc_mcontext.arm_pc;
165
166#elif defined(__mips__)
167
168  typedef struct ucontext {
169    uint32_t sp;
170    uint32_t ra;
171    uint32_t pc;
172  } ucontext_t;
173
174  const ucontext_t* uc = (const ucontext_t*)sigcontext;
175
176  context->uc_mcontext.sp = uc->sp;
177  context->uc_mcontext.pc = uc->pc;
178  context->uc_mcontext.ra = uc->ra;
179#elif defined(__x86__)
180
181  #include <asm/sigcontext.h>
182  #include <asm/ucontext.h>
183  typedef struct ucontext ucontext_t;
184
185  const ucontext_t* uc = (const ucontext_t*)sigcontext;
186
187  context->uc_mcontext.gregs[REG_EBP] = uc->uc_mcontext.gregs[REG_EBP];
188  context->uc_mcontext.gregs[REG_ESP] = uc->uc_mcontext.gregs[REG_ESP];
189  context->uc_mcontext.gregs[REG_EIP] = uc->uc_mcontext.gregs[REG_EIP];
190#endif
191}
192
193//-------------------------------------------------------------------------
194// UnwindThread functions.
195//-------------------------------------------------------------------------
196UnwindThread::UnwindThread() {
197}
198
199UnwindThread::~UnwindThread() {
200}
201
202bool UnwindThread::Init() {
203  return true;
204}
205
206void UnwindThread::ThreadUnwind(
207    siginfo_t* /*siginfo*/, void* sigcontext, size_t num_ignore_frames) {
208  ExtractContext(sigcontext);
209  UnwindFromContext(num_ignore_frames, false);
210}
211
212//-------------------------------------------------------------------------
213// C++ object creation function.
214//-------------------------------------------------------------------------
215Backtrace* CreateCurrentObj() {
216  return new BacktraceCurrent(new UnwindCurrent());
217}
218
219Backtrace* CreateThreadObj(pid_t tid) {
220  UnwindThread* thread_obj = new UnwindThread();
221  return new BacktraceThread(thread_obj, thread_obj, tid);
222}
223