703 lines
22 KiB
C++
703 lines
22 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 <elf.h>
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#include <stdint.h>
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#include <memory>
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#include <string>
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#include <utility>
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#ifdef WITH_DEBUG_FRAME
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#include <7zCrc.h>
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#include <Xz.h>
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#include <XzCrc64.h>
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#endif
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#include <unwindstack/DwarfError.h>
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#include <unwindstack/DwarfSection.h>
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#include <unwindstack/ElfInterface.h>
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#include <unwindstack/Log.h>
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#include <unwindstack/Regs.h>
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#ifdef WITH_DEBUG_FRAME
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#include "DwarfDebugFrame.h"
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#endif
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#include "DwarfEhFrame.h"
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#include "DwarfEhFrameWithHdr.h"
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#include "MemoryBuffer.h"
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#include "Symbols.h"
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namespace unwindstack {
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ElfInterface::~ElfInterface() {
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for (auto symbol : symbols_) {
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delete symbol;
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}
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}
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bool ElfInterface::IsValidPc(uint64_t pc) {
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if (!pt_loads_.empty()) {
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for (auto& entry : pt_loads_) {
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uint64_t start = entry.second.table_offset;
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uint64_t end = start + entry.second.table_size;
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if (pc >= start && pc < end) {
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return true;
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}
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}
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return false;
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}
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// No PT_LOAD data, look for a fde for this pc in the section data.
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if (debug_frame_ != nullptr && debug_frame_->GetFdeFromPc(pc) != nullptr) {
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return true;
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}
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if (eh_frame_ != nullptr && eh_frame_->GetFdeFromPc(pc) != nullptr) {
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return true;
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}
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return false;
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}
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#ifdef WITH_DEBUG_FRAME
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Memory* ElfInterface::CreateGnuDebugdataMemory() {
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if (gnu_debugdata_offset_ == 0 || gnu_debugdata_size_ == 0) {
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return nullptr;
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}
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// TODO: Only call these initialization functions once.
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CrcGenerateTable();
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Crc64GenerateTable();
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// Verify the request is not larger than the max size_t value.
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if (gnu_debugdata_size_ > SIZE_MAX) {
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return nullptr;
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}
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size_t initial_buffer_size;
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if (__builtin_mul_overflow(5, gnu_debugdata_size_, &initial_buffer_size)) {
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return nullptr;
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}
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size_t buffer_increment;
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if (__builtin_mul_overflow(2, gnu_debugdata_size_, &buffer_increment)) {
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return nullptr;
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}
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std::unique_ptr<uint8_t[]> src(new (std::nothrow) uint8_t[gnu_debugdata_size_]);
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if (src.get() == nullptr) {
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return nullptr;
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}
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std::unique_ptr<MemoryBuffer> dst(new MemoryBuffer);
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if (!dst->Resize(initial_buffer_size)) {
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return nullptr;
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}
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if (!memory_->ReadFully(gnu_debugdata_offset_, src.get(), gnu_debugdata_size_)) {
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return nullptr;
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}
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ISzAlloc alloc;
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CXzUnpacker state;
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alloc.Alloc = [](ISzAllocPtr, size_t size) { return malloc(size); };
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alloc.Free = [](ISzAllocPtr, void* ptr) { return free(ptr); };
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XzUnpacker_Construct(&state, &alloc);
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int return_val;
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size_t src_offset = 0;
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size_t dst_offset = 0;
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ECoderStatus status;
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do {
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size_t src_remaining = gnu_debugdata_size_ - src_offset;
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size_t dst_remaining = dst->Size() - dst_offset;
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if (dst_remaining < buffer_increment) {
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size_t new_size;
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if (__builtin_add_overflow(dst->Size(), buffer_increment, &new_size) ||
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!dst->Resize(new_size)) {
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XzUnpacker_Free(&state);
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return nullptr;
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}
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dst_remaining += buffer_increment;
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}
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return_val = XzUnpacker_Code(&state, dst->GetPtr(dst_offset), &dst_remaining, &src[src_offset],
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&src_remaining, true, CODER_FINISH_ANY, &status);
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src_offset += src_remaining;
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dst_offset += dst_remaining;
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} while (return_val == SZ_OK && status == CODER_STATUS_NOT_FINISHED);
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XzUnpacker_Free(&state);
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if (return_val != SZ_OK || !XzUnpacker_IsStreamWasFinished(&state)) {
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return nullptr;
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}
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// Shrink back down to the exact size.
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if (!dst->Resize(dst_offset)) {
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return nullptr;
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}
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return dst.release();
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}
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#endif
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template <typename ElfTypes>
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void ElfInterfaceImpl<ElfTypes>::InitHeaders() {
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if (eh_frame_hdr_offset_ != 0) {
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DwarfEhFrameWithHdr<AddressType>* eh_frame_hdr = new DwarfEhFrameWithHdr<AddressType>(memory_);
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eh_frame_.reset(eh_frame_hdr);
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if (!eh_frame_hdr->EhFrameInit(eh_frame_offset_, eh_frame_size_, eh_frame_section_bias_) ||
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!eh_frame_->Init(eh_frame_hdr_offset_, eh_frame_hdr_size_, eh_frame_hdr_section_bias_)) {
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eh_frame_.reset(nullptr);
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}
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}
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if (eh_frame_.get() == nullptr && eh_frame_offset_ != 0) {
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// If there is an eh_frame section without an eh_frame_hdr section,
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// or using the frame hdr object failed to init.
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eh_frame_.reset(new DwarfEhFrame<AddressType>(memory_));
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if (!eh_frame_->Init(eh_frame_offset_, eh_frame_size_, eh_frame_section_bias_)) {
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eh_frame_.reset(nullptr);
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}
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}
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if (eh_frame_.get() == nullptr) {
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eh_frame_hdr_offset_ = 0;
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eh_frame_hdr_section_bias_ = 0;
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eh_frame_hdr_size_ = static_cast<uint64_t>(-1);
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eh_frame_offset_ = 0;
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eh_frame_section_bias_ = 0;
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eh_frame_size_ = static_cast<uint64_t>(-1);
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}
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#ifdef WITH_DEBUG_FRAME
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if (debug_frame_offset_ != 0) {
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debug_frame_.reset(new DwarfDebugFrame<AddressType>(memory_));
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if (!debug_frame_->Init(debug_frame_offset_, debug_frame_size_, debug_frame_section_bias_)) {
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debug_frame_.reset(nullptr);
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debug_frame_offset_ = 0;
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debug_frame_size_ = static_cast<uint64_t>(-1);
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}
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}
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#endif
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}
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template <typename ElfTypes>
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bool ElfInterfaceImpl<ElfTypes>::ReadAllHeaders(int64_t* load_bias) {
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EhdrType ehdr;
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if (!memory_->ReadFully(0, &ehdr, sizeof(ehdr))) {
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last_error_.code = ERROR_MEMORY_INVALID;
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last_error_.address = 0;
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return false;
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}
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// If we have enough information that this is an elf file, then allow
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// malformed program and section headers.
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ReadProgramHeaders(ehdr, load_bias);
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ReadSectionHeaders(ehdr);
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return true;
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}
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template <typename EhdrType, typename PhdrType>
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int64_t ElfInterface::GetLoadBias(Memory* memory) {
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EhdrType ehdr;
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if (!memory->ReadFully(0, &ehdr, sizeof(ehdr))) {
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return false;
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}
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uint64_t offset = ehdr.e_phoff;
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for (size_t i = 0; i < ehdr.e_phnum; i++, offset += ehdr.e_phentsize) {
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PhdrType phdr;
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if (!memory->ReadFully(offset, &phdr, sizeof(phdr))) {
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return 0;
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}
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// Find the first executable load when looking for the load bias.
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if (phdr.p_type == PT_LOAD && (phdr.p_flags & PF_X)) {
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return static_cast<uint64_t>(phdr.p_vaddr) - phdr.p_offset;
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}
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}
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return 0;
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}
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template <typename ElfTypes>
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void ElfInterfaceImpl<ElfTypes>::ReadProgramHeaders(const EhdrType& ehdr, int64_t* load_bias) {
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uint64_t offset = ehdr.e_phoff;
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bool first_exec_load_header = true;
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for (size_t i = 0; i < ehdr.e_phnum; i++, offset += ehdr.e_phentsize) {
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PhdrType phdr;
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if (!memory_->ReadFully(offset, &phdr, sizeof(phdr))) {
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return;
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}
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switch (phdr.p_type) {
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case PT_LOAD:
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{
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if ((phdr.p_flags & PF_X) == 0) {
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continue;
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}
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pt_loads_[phdr.p_offset] = LoadInfo{phdr.p_offset, phdr.p_vaddr,
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static_cast<size_t>(phdr.p_memsz)};
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// Only set the load bias from the first executable load header.
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if (first_exec_load_header) {
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*load_bias = static_cast<uint64_t>(phdr.p_vaddr) - phdr.p_offset;
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}
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first_exec_load_header = false;
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break;
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}
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case PT_GNU_EH_FRAME:
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// This is really the pointer to the .eh_frame_hdr section.
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eh_frame_hdr_offset_ = phdr.p_offset;
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eh_frame_hdr_section_bias_ = static_cast<uint64_t>(phdr.p_vaddr) - phdr.p_offset;
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eh_frame_hdr_size_ = phdr.p_memsz;
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break;
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case PT_DYNAMIC:
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dynamic_offset_ = phdr.p_offset;
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dynamic_vaddr_start_ = phdr.p_vaddr;
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if (__builtin_add_overflow(dynamic_vaddr_start_, phdr.p_memsz, &dynamic_vaddr_end_)) {
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dynamic_offset_ = 0;
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dynamic_vaddr_start_ = 0;
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dynamic_vaddr_end_ = 0;
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}
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break;
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default:
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HandleUnknownType(phdr.p_type, phdr.p_offset, phdr.p_filesz);
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break;
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}
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}
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}
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template <typename ElfTypes>
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std::string ElfInterfaceImpl<ElfTypes>::ReadBuildID() {
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// Ensure there is no overflow in any of the calulations below.
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uint64_t tmp;
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if (__builtin_add_overflow(gnu_build_id_offset_, gnu_build_id_size_, &tmp)) {
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return "";
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}
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uint64_t offset = 0;
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while (offset < gnu_build_id_size_) {
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if (gnu_build_id_size_ - offset < sizeof(NhdrType)) {
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return "";
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}
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NhdrType hdr;
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if (!memory_->ReadFully(gnu_build_id_offset_ + offset, &hdr, sizeof(hdr))) {
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return "";
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}
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offset += sizeof(hdr);
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if (gnu_build_id_size_ - offset < hdr.n_namesz) {
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return "";
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}
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if (hdr.n_namesz > 0) {
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std::string name(hdr.n_namesz, '\0');
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if (!memory_->ReadFully(gnu_build_id_offset_ + offset, &(name[0]), hdr.n_namesz)) {
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return "";
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}
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// Trim trailing \0 as GNU is stored as a C string in the ELF file.
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if (name.back() == '\0')
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name.resize(name.size() - 1);
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// Align hdr.n_namesz to next power multiple of 4. See man 5 elf.
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offset += (hdr.n_namesz + 3) & ~3;
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if (name == "GNU" && hdr.n_type == NT_GNU_BUILD_ID) {
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if (gnu_build_id_size_ - offset < hdr.n_descsz || hdr.n_descsz == 0) {
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return "";
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}
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std::string build_id(hdr.n_descsz, '\0');
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if (memory_->ReadFully(gnu_build_id_offset_ + offset, &build_id[0], hdr.n_descsz)) {
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return build_id;
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}
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return "";
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}
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}
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// Align hdr.n_descsz to next power multiple of 4. See man 5 elf.
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offset += (hdr.n_descsz + 3) & ~3;
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}
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return "";
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}
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template <typename ElfTypes>
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void ElfInterfaceImpl<ElfTypes>::ReadSectionHeaders(const EhdrType& ehdr) {
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uint64_t offset = ehdr.e_shoff;
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uint64_t sec_offset = 0;
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uint64_t sec_size = 0;
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// Get the location of the section header names.
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// If something is malformed in the header table data, we aren't going
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// to terminate, we'll simply ignore this part.
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ShdrType shdr;
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if (ehdr.e_shstrndx < ehdr.e_shnum) {
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uint64_t sh_offset = offset + ehdr.e_shstrndx * ehdr.e_shentsize;
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if (memory_->ReadFully(sh_offset, &shdr, sizeof(shdr))) {
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sec_offset = shdr.sh_offset;
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sec_size = shdr.sh_size;
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}
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}
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// Skip the first header, it's always going to be NULL.
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offset += ehdr.e_shentsize;
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for (size_t i = 1; i < ehdr.e_shnum; i++, offset += ehdr.e_shentsize) {
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if (!memory_->ReadFully(offset, &shdr, sizeof(shdr))) {
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return;
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}
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if (shdr.sh_type == SHT_SYMTAB || shdr.sh_type == SHT_DYNSYM) {
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// Need to go get the information about the section that contains
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// the string terminated names.
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ShdrType str_shdr;
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if (shdr.sh_link >= ehdr.e_shnum) {
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continue;
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}
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uint64_t str_offset = ehdr.e_shoff + shdr.sh_link * ehdr.e_shentsize;
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if (!memory_->ReadFully(str_offset, &str_shdr, sizeof(str_shdr))) {
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continue;
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}
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if (str_shdr.sh_type != SHT_STRTAB) {
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continue;
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}
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symbols_.push_back(new Symbols(shdr.sh_offset, shdr.sh_size, shdr.sh_entsize,
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str_shdr.sh_offset, str_shdr.sh_size));
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} else if (shdr.sh_type == SHT_PROGBITS && sec_size != 0) {
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// Look for the .debug_frame and .gnu_debugdata.
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if (shdr.sh_name < sec_size) {
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std::string name;
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if (memory_->ReadString(sec_offset + shdr.sh_name, &name, sec_size - shdr.sh_name)) {
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if (name == ".debug_frame") {
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debug_frame_offset_ = shdr.sh_offset;
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debug_frame_size_ = shdr.sh_size;
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debug_frame_section_bias_ = static_cast<uint64_t>(shdr.sh_addr) - shdr.sh_offset;
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} else if (name == ".gnu_debugdata") {
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gnu_debugdata_offset_ = shdr.sh_offset;
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gnu_debugdata_size_ = shdr.sh_size;
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} else if (name == ".eh_frame") {
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eh_frame_offset_ = shdr.sh_offset;
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eh_frame_section_bias_ = static_cast<uint64_t>(shdr.sh_addr) - shdr.sh_offset;
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eh_frame_size_ = shdr.sh_size;
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} else if (eh_frame_hdr_offset_ == 0 && name == ".eh_frame_hdr") {
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eh_frame_hdr_offset_ = shdr.sh_offset;
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eh_frame_hdr_section_bias_ = static_cast<uint64_t>(shdr.sh_addr) - shdr.sh_offset;
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eh_frame_hdr_size_ = shdr.sh_size;
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} else if (name == ".data") {
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data_offset_ = shdr.sh_offset;
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data_vaddr_start_ = shdr.sh_addr;
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if (__builtin_add_overflow(data_vaddr_start_, shdr.sh_size, &data_vaddr_end_)) {
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data_offset_ = 0;
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data_vaddr_start_ = 0;
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data_vaddr_end_ = 0;
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}
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}
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}
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}
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} else if (shdr.sh_type == SHT_STRTAB) {
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// In order to read soname, keep track of address to offset mapping.
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strtabs_.push_back(std::make_pair<uint64_t, uint64_t>(static_cast<uint64_t>(shdr.sh_addr),
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static_cast<uint64_t>(shdr.sh_offset)));
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} else if (shdr.sh_type == SHT_NOTE) {
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if (shdr.sh_name < sec_size) {
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std::string name;
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if (memory_->ReadString(sec_offset + shdr.sh_name, &name, sec_size - shdr.sh_name) &&
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name == ".note.gnu.build-id") {
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gnu_build_id_offset_ = shdr.sh_offset;
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gnu_build_id_size_ = shdr.sh_size;
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}
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}
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}
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}
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}
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template <typename ElfTypes>
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std::string ElfInterfaceImpl<ElfTypes>::GetSoname() {
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if (soname_type_ == SONAME_INVALID) {
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return "";
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}
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if (soname_type_ == SONAME_VALID) {
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return soname_;
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}
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soname_type_ = SONAME_INVALID;
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uint64_t soname_offset = 0;
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uint64_t strtab_addr = 0;
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uint64_t strtab_size = 0;
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// Find the soname location from the dynamic headers section.
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DynType dyn;
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uint64_t offset = dynamic_offset_;
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uint64_t max_offset = offset + dynamic_vaddr_end_ - dynamic_vaddr_start_;
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for (uint64_t offset = dynamic_offset_; offset < max_offset; offset += sizeof(DynType)) {
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if (!memory_->ReadFully(offset, &dyn, sizeof(dyn))) {
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last_error_.code = ERROR_MEMORY_INVALID;
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last_error_.address = offset;
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return "";
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}
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if (dyn.d_tag == DT_STRTAB) {
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strtab_addr = dyn.d_un.d_ptr;
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} else if (dyn.d_tag == DT_STRSZ) {
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strtab_size = dyn.d_un.d_val;
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} else if (dyn.d_tag == DT_SONAME) {
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soname_offset = dyn.d_un.d_val;
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} else if (dyn.d_tag == DT_NULL) {
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break;
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}
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}
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// Need to map the strtab address to the real offset.
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for (const auto& entry : strtabs_) {
|
|
if (entry.first == strtab_addr) {
|
|
soname_offset = entry.second + soname_offset;
|
|
uint64_t soname_max = entry.second + strtab_size;
|
|
if (soname_offset >= soname_max) {
|
|
return "";
|
|
}
|
|
if (!memory_->ReadString(soname_offset, &soname_, soname_max - soname_offset)) {
|
|
return "";
|
|
}
|
|
soname_type_ = SONAME_VALID;
|
|
return soname_;
|
|
}
|
|
}
|
|
return "";
|
|
}
|
|
|
|
template <typename ElfTypes>
|
|
bool ElfInterfaceImpl<ElfTypes>::GetFunctionName(uint64_t addr, std::string* name,
|
|
uint64_t* func_offset) {
|
|
if (symbols_.empty()) {
|
|
return false;
|
|
}
|
|
|
|
for (const auto symbol : symbols_) {
|
|
if (symbol->template GetName<SymType>(addr, memory_, name, func_offset)) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
template <typename ElfTypes>
|
|
bool ElfInterfaceImpl<ElfTypes>::GetGlobalVariable(const std::string& name,
|
|
uint64_t* memory_address) {
|
|
if (symbols_.empty()) {
|
|
return false;
|
|
}
|
|
|
|
for (const auto symbol : symbols_) {
|
|
if (symbol->template GetGlobal<SymType>(memory_, name, memory_address)) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool ElfInterface::Step(uint64_t pc, Regs* regs, Memory* process_memory, bool* finished,
|
|
bool* is_signal_frame) {
|
|
last_error_.code = ERROR_NONE;
|
|
last_error_.address = 0;
|
|
|
|
// Try the debug_frame first since it contains the most specific unwind
|
|
// information.
|
|
DwarfSection* debug_frame = debug_frame_.get();
|
|
if (debug_frame != nullptr &&
|
|
debug_frame->Step(pc, regs, process_memory, finished, is_signal_frame)) {
|
|
return true;
|
|
}
|
|
|
|
// Try the eh_frame next.
|
|
DwarfSection* eh_frame = eh_frame_.get();
|
|
if (eh_frame != nullptr && eh_frame->Step(pc, regs, process_memory, finished, is_signal_frame)) {
|
|
return true;
|
|
}
|
|
|
|
if (gnu_debugdata_interface_ != nullptr &&
|
|
gnu_debugdata_interface_->Step(pc, regs, process_memory, finished, is_signal_frame)) {
|
|
return true;
|
|
}
|
|
|
|
// Set the error code based on the first error encountered.
|
|
DwarfSection* section = nullptr;
|
|
if (debug_frame_ != nullptr) {
|
|
section = debug_frame_.get();
|
|
} else if (eh_frame_ != nullptr) {
|
|
section = eh_frame_.get();
|
|
} else if (gnu_debugdata_interface_ != nullptr) {
|
|
last_error_ = gnu_debugdata_interface_->last_error();
|
|
return false;
|
|
} else {
|
|
return false;
|
|
}
|
|
|
|
// Convert the DWARF ERROR to an external error.
|
|
DwarfErrorCode code = section->LastErrorCode();
|
|
switch (code) {
|
|
case DWARF_ERROR_NONE:
|
|
last_error_.code = ERROR_NONE;
|
|
break;
|
|
|
|
case DWARF_ERROR_MEMORY_INVALID:
|
|
last_error_.code = ERROR_MEMORY_INVALID;
|
|
last_error_.address = section->LastErrorAddress();
|
|
break;
|
|
|
|
case DWARF_ERROR_ILLEGAL_VALUE:
|
|
case DWARF_ERROR_ILLEGAL_STATE:
|
|
case DWARF_ERROR_STACK_INDEX_NOT_VALID:
|
|
case DWARF_ERROR_TOO_MANY_ITERATIONS:
|
|
case DWARF_ERROR_CFA_NOT_DEFINED:
|
|
case DWARF_ERROR_NO_FDES:
|
|
last_error_.code = ERROR_UNWIND_INFO;
|
|
break;
|
|
|
|
case DWARF_ERROR_NOT_IMPLEMENTED:
|
|
case DWARF_ERROR_UNSUPPORTED_VERSION:
|
|
last_error_.code = ERROR_UNSUPPORTED;
|
|
break;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// This is an estimation of the size of the elf file using the location
|
|
// of the section headers and size. This assumes that the section headers
|
|
// are at the end of the elf file. If the elf has a load bias, the size
|
|
// will be too large, but this is acceptable.
|
|
template <typename ElfTypes>
|
|
void ElfInterfaceImpl<ElfTypes>::GetMaxSize(Memory* memory, uint64_t* size) {
|
|
EhdrType ehdr;
|
|
if (!memory->ReadFully(0, &ehdr, sizeof(ehdr))) {
|
|
return;
|
|
}
|
|
if (ehdr.e_shnum == 0) {
|
|
return;
|
|
}
|
|
*size = ehdr.e_shoff + ehdr.e_shentsize * ehdr.e_shnum;
|
|
}
|
|
|
|
template <typename EhdrType, typename ShdrType>
|
|
bool GetBuildIDInfo(Memory* memory, uint64_t* build_id_offset, uint64_t* build_id_size) {
|
|
EhdrType ehdr;
|
|
if (!memory->ReadFully(0, &ehdr, sizeof(ehdr))) {
|
|
return false;
|
|
}
|
|
|
|
uint64_t offset = ehdr.e_shoff;
|
|
uint64_t sec_offset;
|
|
uint64_t sec_size;
|
|
ShdrType shdr;
|
|
if (ehdr.e_shstrndx >= ehdr.e_shnum) {
|
|
return false;
|
|
}
|
|
|
|
uint64_t sh_offset = offset + ehdr.e_shstrndx * ehdr.e_shentsize;
|
|
if (!memory->ReadFully(sh_offset, &shdr, sizeof(shdr))) {
|
|
return false;
|
|
}
|
|
sec_offset = shdr.sh_offset;
|
|
sec_size = shdr.sh_size;
|
|
|
|
// Skip the first header, it's always going to be NULL.
|
|
offset += ehdr.e_shentsize;
|
|
for (size_t i = 1; i < ehdr.e_shnum; i++, offset += ehdr.e_shentsize) {
|
|
if (!memory->ReadFully(offset, &shdr, sizeof(shdr))) {
|
|
return false;
|
|
}
|
|
std::string name;
|
|
if (shdr.sh_type == SHT_NOTE && shdr.sh_name < sec_size &&
|
|
memory->ReadString(sec_offset + shdr.sh_name, &name, sec_size - shdr.sh_name) &&
|
|
name == ".note.gnu.build-id") {
|
|
*build_id_offset = shdr.sh_offset;
|
|
*build_id_size = shdr.sh_size;
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
template <typename EhdrType, typename ShdrType, typename NhdrType>
|
|
std::string ElfInterface::ReadBuildIDFromMemory(Memory* memory) {
|
|
uint64_t note_offset;
|
|
uint64_t note_size;
|
|
if (!GetBuildIDInfo<EhdrType, ShdrType>(memory, ¬e_offset, ¬e_size)) {
|
|
return "";
|
|
}
|
|
|
|
// Ensure there is no overflow in any of the calculations below.
|
|
uint64_t tmp;
|
|
if (__builtin_add_overflow(note_offset, note_size, &tmp)) {
|
|
return "";
|
|
}
|
|
|
|
uint64_t offset = 0;
|
|
while (offset < note_size) {
|
|
if (note_size - offset < sizeof(NhdrType)) {
|
|
return "";
|
|
}
|
|
NhdrType hdr;
|
|
if (!memory->ReadFully(note_offset + offset, &hdr, sizeof(hdr))) {
|
|
return "";
|
|
}
|
|
offset += sizeof(hdr);
|
|
|
|
if (note_size - offset < hdr.n_namesz) {
|
|
return "";
|
|
}
|
|
if (hdr.n_namesz > 0) {
|
|
std::string name(hdr.n_namesz, '\0');
|
|
if (!memory->ReadFully(note_offset + offset, &(name[0]), hdr.n_namesz)) {
|
|
return "";
|
|
}
|
|
|
|
// Trim trailing \0 as GNU is stored as a C string in the ELF file.
|
|
if (name.back() == '\0') name.resize(name.size() - 1);
|
|
|
|
// Align hdr.n_namesz to next power multiple of 4. See man 5 elf.
|
|
offset += (hdr.n_namesz + 3) & ~3;
|
|
|
|
if (name == "GNU" && hdr.n_type == NT_GNU_BUILD_ID) {
|
|
if (note_size - offset < hdr.n_descsz || hdr.n_descsz == 0) {
|
|
return "";
|
|
}
|
|
std::string build_id(hdr.n_descsz, '\0');
|
|
if (memory->ReadFully(note_offset + offset, &build_id[0], hdr.n_descsz)) {
|
|
return build_id;
|
|
}
|
|
return "";
|
|
}
|
|
}
|
|
// Align hdr.n_descsz to next power multiple of 4. See man 5 elf.
|
|
offset += (hdr.n_descsz + 3) & ~3;
|
|
}
|
|
return "";
|
|
}
|
|
|
|
// Instantiate all of the needed template functions.
|
|
template class ElfInterfaceImpl<ElfTypes32>;
|
|
template class ElfInterfaceImpl<ElfTypes64>;
|
|
|
|
template int64_t ElfInterface::GetLoadBias<Elf32_Ehdr, Elf32_Phdr>(Memory*);
|
|
template int64_t ElfInterface::GetLoadBias<Elf64_Ehdr, Elf64_Phdr>(Memory*);
|
|
|
|
template std::string ElfInterface::ReadBuildIDFromMemory<Elf32_Ehdr, Elf32_Shdr, Elf32_Nhdr>(
|
|
Memory*);
|
|
template std::string ElfInterface::ReadBuildIDFromMemory<Elf64_Ehdr, Elf64_Shdr, Elf64_Nhdr>(
|
|
Memory*);
|
|
|
|
} // namespace unwindstack
|