9b8f545920
Mark a CIE with a S in its augmentation string as signal frame.
This allows the code to properly handle signal frame data if none
of the signal frame pattern matchers work.
For a signal frame, DwarfSectionImpl<AddressType>::Eval needs to
continue the unwinding even if PC is zero. A zero PC means that the
program has crashed, and we should try to recover the real PC using the
return address on the stack or LR. This behavior is tested by
UnwindOffline.signal_{x86,x86_64}, which modify the libc.so files
so that the signal frame pattern matcher fails and the CIE/FDE
data is used instead.
Test: libunwindstack_test
Change-Id: I4655b070028fd984345311a5e743796f8c30ed36
75 lines
2 KiB
C++
75 lines
2 KiB
C++
/*
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* Copyright (C) 2017 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 <stdint.h>
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#include <deque>
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#include <string>
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#include <unwindstack/Elf.h>
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#include <unwindstack/ElfInterface.h>
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#include <unwindstack/Memory.h>
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#include <unwindstack/Regs.h>
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#include "ElfFake.h"
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#include "RegsFake.h"
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namespace unwindstack {
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std::deque<FunctionData> ElfInterfaceFake::functions_;
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std::deque<StepData> ElfInterfaceFake::steps_;
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bool ElfInterfaceFake::GetFunctionName(uint64_t, std::string* name, uint64_t* offset) {
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if (functions_.empty()) {
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return false;
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}
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auto entry = functions_.front();
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functions_.pop_front();
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*name = entry.name;
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*offset = entry.offset;
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return true;
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}
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bool ElfInterfaceFake::GetGlobalVariable(const std::string& global, uint64_t* offset) {
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auto entry = globals_.find(global);
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if (entry == globals_.end()) {
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return false;
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}
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*offset = entry->second;
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return true;
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}
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bool ElfInterfaceFake::Step(uint64_t, Regs* regs, Memory*, bool* finished, bool* is_signal_frame) {
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if (steps_.empty()) {
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return false;
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}
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auto entry = steps_.front();
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steps_.pop_front();
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if (entry.pc == 0 && entry.sp == 0 && !entry.finished) {
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// Pretend as though there is no frame.
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return false;
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}
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RegsFake* fake_regs = reinterpret_cast<RegsFake*>(regs);
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fake_regs->set_pc(entry.pc);
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fake_regs->set_sp(entry.sp);
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*finished = entry.finished;
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*is_signal_frame = false;
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return true;
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}
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} // namespace unwindstack
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