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/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "libbacktrace"
#include <sys/types.h>
#include <cutils/log.h>
#include <backtrace/backtrace.h>
#define UNW_LOCAL_ONLY
#include <libunwind.h>
#include "UnwindCurrent.h"
// Define the ucontext_t structures needed for each supported arch.
#if defined(__arm__)
// The current version of the <signal.h> doesn't define ucontext_t.
#include <asm/sigcontext.h> // Ensure 'struct sigcontext' is defined.
// Machine context at the time a signal was raised.
typedef struct ucontext {
uint32_t uc_flags;
struct ucontext* uc_link;
stack_t uc_stack;
struct sigcontext uc_mcontext;
uint32_t uc_sigmask;
} ucontext_t;
#elif defined(__mips__)
typedef struct ucontext {
uint32_t sp;
uint32_t ra;
uint32_t pc;
} ucontext_t;
#elif defined(__i386__)
#include <asm/sigcontext.h>
#include <asm/ucontext.h>
typedef struct ucontext ucontext_t;
#else
#error Unsupported architecture.
#endif
//-------------------------------------------------------------------------
// UnwindCurrent functions.
//-------------------------------------------------------------------------
UnwindCurrent::UnwindCurrent() {
}
UnwindCurrent::~UnwindCurrent() {
}
bool UnwindCurrent::Unwind(size_t num_ignore_frames) {
int ret = unw_getcontext(&context_);
if (ret < 0) {
BACK_LOGW("unw_getcontext failed %d", ret);
return false;
}
return UnwindFromContext(num_ignore_frames, true);
}
std::string UnwindCurrent::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) {
*offset = 0;
char buf[512];
unw_word_t value;
if (unw_get_proc_name_by_ip(unw_local_addr_space, pc, buf, sizeof(buf),
&value, &context_) >= 0 && buf[0] != '\0') {
*offset = static_cast<uintptr_t>(value);
return buf;
}
return "";
}
bool UnwindCurrent::UnwindFromContext(size_t num_ignore_frames, bool resolve) {
backtrace_t* backtrace = GetBacktraceData();
backtrace->num_frames = 0;
// The cursor structure is pretty large, do not put it on the stack.
unw_cursor_t* cursor = new unw_cursor_t;
int ret = unw_init_local(cursor, &context_);
if (ret < 0) {
BACK_LOGW("unw_init_local failed %d", ret);
return false;
}
do {
unw_word_t pc;
ret = unw_get_reg(cursor, UNW_REG_IP, &pc);
if (ret < 0) {
BACK_LOGW("Failed to read IP %d", ret);
break;
}
unw_word_t sp;
ret = unw_get_reg(cursor, UNW_REG_SP, &sp);
if (ret < 0) {
BACK_LOGW("Failed to read SP %d", ret);
break;
}
if (num_ignore_frames == 0) {
size_t num_frames = backtrace->num_frames;
backtrace_frame_data_t* frame = &backtrace->frames[num_frames];
frame->pc = static_cast<uintptr_t>(pc);
frame->sp = static_cast<uintptr_t>(sp);
frame->stack_size = 0;
frame->map_name = NULL;
frame->map_offset = 0;
frame->func_name = NULL;
frame->func_offset = 0;
if (num_frames > 0) {
// Set the stack size for the previous frame.
backtrace_frame_data_t* prev = &backtrace->frames[num_frames-1];
prev->stack_size = frame->sp - prev->sp;
}
if (resolve) {
std::string func_name = backtrace_obj_->GetFunctionName(frame->pc, &frame->func_offset);
if (!func_name.empty()) {
frame->func_name = strdup(func_name.c_str());
}
uintptr_t map_start;
frame->map_name = backtrace_obj_->GetMapName(frame->pc, &map_start);
if (frame->map_name) {
frame->map_offset = frame->pc - map_start;
}
}
backtrace->num_frames++;
} else {
num_ignore_frames--;
}
ret = unw_step (cursor);
} while (ret > 0 && backtrace->num_frames < MAX_BACKTRACE_FRAMES);
delete cursor;
return true;
}
void UnwindCurrent::ExtractContext(void* sigcontext) {
unw_tdep_context_t* context = reinterpret_cast<unw_tdep_context_t*>(&context_);
const ucontext_t* uc = reinterpret_cast<const ucontext_t*>(sigcontext);
#if defined(__arm__)
context->regs[0] = uc->uc_mcontext.arm_r0;
context->regs[1] = uc->uc_mcontext.arm_r1;
context->regs[2] = uc->uc_mcontext.arm_r2;
context->regs[3] = uc->uc_mcontext.arm_r3;
context->regs[4] = uc->uc_mcontext.arm_r4;
context->regs[5] = uc->uc_mcontext.arm_r5;
context->regs[6] = uc->uc_mcontext.arm_r6;
context->regs[7] = uc->uc_mcontext.arm_r7;
context->regs[8] = uc->uc_mcontext.arm_r8;
context->regs[9] = uc->uc_mcontext.arm_r9;
context->regs[10] = uc->uc_mcontext.arm_r10;
context->regs[11] = uc->uc_mcontext.arm_fp;
context->regs[12] = uc->uc_mcontext.arm_ip;
context->regs[13] = uc->uc_mcontext.arm_sp;
context->regs[14] = uc->uc_mcontext.arm_lr;
context->regs[15] = uc->uc_mcontext.arm_pc;
#elif defined(__mips__)
context->uc_mcontext.sp = uc->sp;
context->uc_mcontext.pc = uc->pc;
context->uc_mcontext.ra = uc->ra;
#elif defined(__i386__)
context->uc_mcontext.gregs[REG_EBP] = uc->uc_mcontext.gregs[REG_EBP];
context->uc_mcontext.gregs[REG_ESP] = uc->uc_mcontext.gregs[REG_ESP];
context->uc_mcontext.gregs[REG_EIP] = uc->uc_mcontext.gregs[REG_EIP];
#endif
}
//-------------------------------------------------------------------------
// UnwindThread functions.
//-------------------------------------------------------------------------
UnwindThread::UnwindThread() {
}
UnwindThread::~UnwindThread() {
}
bool UnwindThread::Init() {
return true;
}
void UnwindThread::ThreadUnwind(
siginfo_t* /*siginfo*/, void* sigcontext, size_t num_ignore_frames) {
ExtractContext(sigcontext);
UnwindFromContext(num_ignore_frames, false);
}
//-------------------------------------------------------------------------
// C++ object creation function.
//-------------------------------------------------------------------------
Backtrace* CreateCurrentObj() {
return new BacktraceCurrent(new UnwindCurrent());
}
Backtrace* CreateThreadObj(pid_t tid) {
UnwindThread* thread_obj = new UnwindThread();
return new BacktraceThread(thread_obj, thread_obj, tid);
}
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