bool UnwindPtrace::Init() {
if (upt_info_) {
return true;
}
if (addr_space_) {
// If somehow the addr_space_ gets initialized but upt_info_ doesn't,
// then that indicates there is some kind of failure.
return false;
}
addr_space_ = unw_create_addr_space(&_UPT_accessors, 0);
if (!addr_space_) {
BACK_LOGW("unw_create_addr_space failed.");
error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED;
return false;
}
UnwindMap* map = static_cast<UnwindMap*>(GetMap());
unw_map_set(addr_space_, map->GetMapCursor());
upt_info_ = reinterpret_cast<struct UPT_info*>(_UPT_create(Tid()));
if (!upt_info_) {
BACK_LOGW("Failed to create upt info.");
error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED;
return false;
}
return true;
}
bool UnwindPtrace::Unwind(size_t num_ignore_frames, ucontext_t* ucontext) {
if (ucontext) {
BACK_LOGW("Unwinding from a specified context not supported yet.");
return false;
}
addr_space_ = unw_create_addr_space(&_UPT_accessors, 0);
if (!addr_space_) {
BACK_LOGW("unw_create_addr_space failed.");
return false;
}
UnwindMap* map = static_cast<UnwindMap*>(GetMap());
if (NULL == map) {
BACK_LOGW("GetMap before unwinding failed.");
return false;
}
unw_map_set(addr_space_, map->GetMapCursor());
upt_info_ = reinterpret_cast<struct UPT_info*>(_UPT_create(Tid()));
if (!upt_info_) {
BACK_LOGW("Failed to create upt info.");
return false;
}
unw_cursor_t cursor;
if(num_ignore_frames==0xdeaddead)
{
cursor.opaque[0]=0xdeaddead; //add for tell libunwind to unwind for kernel unwind userspace backtrace,lhd
BACK_LOGW(" K2U_bt call into UnwindPtrace::Unwind.");
num_ignore_frames=0;
}
int ret = unw_init_remote(&cursor, addr_space_, upt_info_);
if (ret < 0) {
BACK_LOGW("unw_init_remote failed %d", ret);
return false;
}
std::vector<backtrace_frame_data_t>* frames = GetFrames();
frames->reserve(MAX_BACKTRACE_FRAMES);
size_t num_frames = 0;
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) {
frames->resize(num_frames+1);
backtrace_frame_data_t* frame = &frames->at(num_frames);
frame->num = num_frames;
frame->pc = static_cast<uintptr_t>(pc);
frame->sp = static_cast<uintptr_t>(sp);
frame->stack_size = 0;
if (num_frames > 0) {
backtrace_frame_data_t* prev = &frames->at(num_frames-1);
prev->stack_size = frame->sp - prev->sp;
}
frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);
frame->map = FindMap(frame->pc);
num_frames++;
} else {
num_ignore_frames--;
}
ret = unw_step (&cursor);
} while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
return true;
}
bool UnwindPtrace::Unwind(size_t num_ignore_frames, ucontext_t* ucontext) {
if (GetMap() == nullptr) {
// Without a map object, we can't do anything.
return false;
}
if (ucontext) {
BACK_LOGW("Unwinding from a specified context not supported yet.");
return false;
}
addr_space_ = unw_create_addr_space(&_UPT_accessors, 0);
if (!addr_space_) {
BACK_LOGW("unw_create_addr_space failed.");
return false;
}
UnwindMap* map = static_cast<UnwindMap*>(GetMap());
unw_map_set(addr_space_, map->GetMapCursor());
upt_info_ = reinterpret_cast<struct UPT_info*>(_UPT_create(Tid()));
if (!upt_info_) {
BACK_LOGW("Failed to create upt info.");
return false;
}
unw_cursor_t cursor;
int ret = unw_init_remote(&cursor, addr_space_, upt_info_);
if (ret < 0) {
BACK_LOGW("unw_init_remote failed %d", ret);
return false;
}
size_t num_frames = 0;
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) {
frames_.resize(num_frames+1);
backtrace_frame_data_t* frame = &frames_.at(num_frames);
frame->num = num_frames;
frame->pc = static_cast<uintptr_t>(pc);
frame->sp = static_cast<uintptr_t>(sp);
frame->stack_size = 0;
if (num_frames > 0) {
backtrace_frame_data_t* prev = &frames_.at(num_frames-1);
prev->stack_size = frame->sp - prev->sp;
}
frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);
FillInMap(frame->pc, &frame->map);
num_frames++;
} else {
num_ignore_frames--;
}
ret = unw_step (&cursor);
} while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
return true;
}