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/*
* Copyright (C) 2018 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <pthread.h>
#include <stdint.h>
#include <memory>
#include <string>
#include <vector>
#include <unwindstack/Elf.h>
#include <unwindstack/LocalUnwinder.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/Maps.h>
#include <unwindstack/Memory.h>
#include <unwindstack/Regs.h>
#include <unwindstack/RegsGetLocal.h>
namespace unwindstack {
bool LocalUnwinder::Init() {
pthread_rwlock_init(&maps_rwlock_, nullptr);
// Create the maps.
maps_.reset(new unwindstack::LocalUpdatableMaps());
if (!maps_->Parse()) {
maps_.reset();
return false;
}
process_memory_ = unwindstack::Memory::CreateProcessMemory(getpid());
return true;
}
bool LocalUnwinder::ShouldSkipLibrary(const std::string& map_name) {
for (const std::string& skip_library : skip_libraries_) {
if (skip_library == map_name) {
return true;
}
}
return false;
}
MapInfo* LocalUnwinder::GetMapInfo(uint64_t pc) {
pthread_rwlock_rdlock(&maps_rwlock_);
MapInfo* map_info = maps_->Find(pc);
pthread_rwlock_unlock(&maps_rwlock_);
if (map_info == nullptr) {
pthread_rwlock_wrlock(&maps_rwlock_);
// This is guaranteed not to invalidate any previous MapInfo objects so
// we don't need to worry about any MapInfo* values already in use.
if (maps_->Reparse()) {
map_info = maps_->Find(pc);
}
pthread_rwlock_unlock(&maps_rwlock_);
}
return map_info;
}
bool LocalUnwinder::Unwind(std::vector<LocalFrameData>* frame_info, size_t max_frames) {
std::unique_ptr<unwindstack::Regs> regs(unwindstack::Regs::CreateFromLocal());
unwindstack::RegsGetLocal(regs.get());
size_t num_frames = 0;
bool adjust_pc = false;
while (true) {
uint64_t cur_pc = regs->pc();
uint64_t cur_sp = regs->sp();
MapInfo* map_info = GetMapInfo(cur_pc);
if (map_info == nullptr) {
break;
}
Elf* elf = map_info->GetElf(process_memory_, true);
uint64_t rel_pc = elf->GetRelPc(cur_pc, map_info);
uint64_t step_pc = rel_pc;
uint64_t pc_adjustment;
if (adjust_pc) {
pc_adjustment = regs->GetPcAdjustment(rel_pc, elf);
} else {
pc_adjustment = 0;
}
step_pc -= pc_adjustment;
// Skip any locations that are within this library.
if (num_frames != 0 || !ShouldSkipLibrary(map_info->name)) {
// Add frame information.
std::string func_name;
uint64_t func_offset;
if (elf->GetFunctionName(rel_pc, &func_name, &func_offset)) {
frame_info->emplace_back(map_info, cur_pc - pc_adjustment, rel_pc - pc_adjustment,
func_name, func_offset);
} else {
frame_info->emplace_back(map_info, cur_pc - pc_adjustment, rel_pc - pc_adjustment, "", 0);
}
num_frames++;
}
if (!elf->valid()) {
break;
}
if (frame_info->size() == max_frames) {
break;
}
adjust_pc = true;
bool finished;
if (!elf->Step(rel_pc, step_pc, regs.get(), process_memory_.get(), &finished) || finished) {
break;
}
// pc and sp are the same, terminate the unwind.
if (cur_pc == regs->pc() && cur_sp == regs->sp()) {
break;
}
}
return num_frames != 0;
}
} // namespace unwindstack