a2efd3ac7a
This new version doesn't require any specialized thread implementation, it uses the Current implementation to do its job. In addition, it runs much faster when multiple threads are trying to unwind at the same time since the global signal lock is held for only a small amount of time. Even running through the threads one at a time should be faster since it no longer requires two passes through the unwound stacks. The new code now allows multiple simultaneous unwinds of the same thread. Finally, add the ability to unwind from a ucontext_t passed in. This functionality doesn't work for remote unwinds yet. Change-Id: I4d181d7ca5ffd2acfd1686e668e6d21e36b425cb
137 lines
3.8 KiB
C++
137 lines
3.8 KiB
C++
/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <backtrace/Backtrace.h>
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#include <backtrace/BacktraceMap.h>
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#include <sys/types.h>
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#include <string.h>
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#include <libunwind.h>
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#include <libunwind-ptrace.h>
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#include "BacktraceLog.h"
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#include "UnwindMap.h"
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#include "UnwindPtrace.h"
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UnwindPtrace::UnwindPtrace() : addr_space_(NULL), upt_info_(NULL) {
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}
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UnwindPtrace::~UnwindPtrace() {
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if (upt_info_) {
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_UPT_destroy(upt_info_);
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upt_info_ = NULL;
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}
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if (addr_space_) {
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// Remove the map from the address space before destroying it.
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// It will be freed in the UnwindMap destructor.
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unw_map_set(addr_space_, NULL);
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unw_destroy_addr_space(addr_space_);
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addr_space_ = NULL;
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}
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}
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bool UnwindPtrace::Unwind(size_t num_ignore_frames, ucontext_t* ucontext) {
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if (ucontext) {
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BACK_LOGW("Unwinding from a specified context not supported yet.");
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return false;
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}
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addr_space_ = unw_create_addr_space(&_UPT_accessors, 0);
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if (!addr_space_) {
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BACK_LOGW("unw_create_addr_space failed.");
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return false;
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}
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UnwindMap* map = static_cast<UnwindMap*>(GetMap());
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unw_map_set(addr_space_, map->GetMapCursor());
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upt_info_ = reinterpret_cast<struct UPT_info*>(_UPT_create(Tid()));
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if (!upt_info_) {
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BACK_LOGW("Failed to create upt info.");
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return false;
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}
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unw_cursor_t cursor;
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int ret = unw_init_remote(&cursor, addr_space_, upt_info_);
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if (ret < 0) {
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BACK_LOGW("unw_init_remote failed %d", ret);
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return false;
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}
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std::vector<backtrace_frame_data_t>* frames = GetFrames();
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frames->reserve(MAX_BACKTRACE_FRAMES);
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size_t num_frames = 0;
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do {
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unw_word_t pc;
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ret = unw_get_reg(&cursor, UNW_REG_IP, &pc);
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if (ret < 0) {
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BACK_LOGW("Failed to read IP %d", ret);
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break;
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}
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unw_word_t sp;
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ret = unw_get_reg(&cursor, UNW_REG_SP, &sp);
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if (ret < 0) {
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BACK_LOGW("Failed to read SP %d", ret);
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break;
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}
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if (num_ignore_frames == 0) {
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frames->resize(num_frames+1);
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backtrace_frame_data_t* frame = &frames->at(num_frames);
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frame->num = num_frames;
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frame->pc = static_cast<uintptr_t>(pc);
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frame->sp = static_cast<uintptr_t>(sp);
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frame->stack_size = 0;
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if (num_frames > 0) {
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backtrace_frame_data_t* prev = &frames->at(num_frames-1);
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prev->stack_size = frame->sp - prev->sp;
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}
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frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);
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frame->map = FindMap(frame->pc);
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num_frames++;
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} else {
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num_ignore_frames--;
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}
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ret = unw_step (&cursor);
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} while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
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return true;
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}
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std::string UnwindPtrace::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) {
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*offset = 0;
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char buf[512];
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unw_word_t value;
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if (unw_get_proc_name_by_ip(addr_space_, pc, buf, sizeof(buf), &value,
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upt_info_) >= 0 && buf[0] != '\0') {
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*offset = static_cast<uintptr_t>(value);
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return buf;
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}
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return "";
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}
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//-------------------------------------------------------------------------
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// C++ object creation function.
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//-------------------------------------------------------------------------
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Backtrace* CreatePtraceObj(pid_t pid, pid_t tid, BacktraceMap* map) {
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return new BacktracePtrace(new UnwindPtrace(), pid, tid, map);
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}
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