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394 lines
12 KiB
394 lines
12 KiB
/* |
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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 <7zCrc.h> |
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#include <Xz.h> |
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#include <XzCrc64.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/Memory.h> |
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#include <unwindstack/Regs.h> |
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#include "DwarfDebugFrame.h" |
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#include "DwarfEhFrame.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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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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std::vector<uint8_t> src(gnu_debugdata_size_); |
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if (!memory_->Read(gnu_debugdata_offset_, src.data(), gnu_debugdata_size_)) { |
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gnu_debugdata_offset_ = 0; |
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gnu_debugdata_size_ = static_cast<uint64_t>(-1); |
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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 = [](void*, size_t size) { return malloc(size); }; |
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alloc.Free = [](void*, void* ptr) { return free(ptr); }; |
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XzUnpacker_Construct(&state, &alloc); |
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std::unique_ptr<MemoryBuffer> dst(new MemoryBuffer); |
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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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dst->Resize(5 * gnu_debugdata_size_); |
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do { |
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size_t src_remaining = src.size() - src_offset; |
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size_t dst_remaining = dst->Size() - dst_offset; |
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if (dst_remaining < 2 * gnu_debugdata_size_) { |
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dst->Resize(dst->Size() + 2 * gnu_debugdata_size_); |
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dst_remaining += 2 * gnu_debugdata_size_; |
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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, 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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gnu_debugdata_offset_ = 0; |
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gnu_debugdata_size_ = static_cast<uint64_t>(-1); |
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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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dst->Resize(dst_offset); |
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return dst.release(); |
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} |
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template <typename AddressType> |
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void ElfInterface::InitHeadersWithTemplate() { |
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if (eh_frame_offset_ != 0) { |
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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_)) { |
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eh_frame_.reset(nullptr); |
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eh_frame_offset_ = 0; |
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eh_frame_size_ = static_cast<uint64_t>(-1); |
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} |
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} |
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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_)) { |
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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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} |
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template <typename EhdrType, typename PhdrType, typename ShdrType> |
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bool ElfInterface::ReadAllHeaders() { |
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EhdrType ehdr; |
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if (!memory_->Read(0, &ehdr, sizeof(ehdr))) { |
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return false; |
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} |
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if (!ReadProgramHeaders<EhdrType, PhdrType>(ehdr)) { |
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return false; |
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} |
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// We could still potentially unwind without the section header |
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// information, so ignore any errors. |
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if (!ReadSectionHeaders<EhdrType, ShdrType>(ehdr)) { |
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log(0, "Malformed section header found, ignoring..."); |
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} |
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return true; |
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} |
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template <typename EhdrType, typename PhdrType> |
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bool ElfInterface::ReadProgramHeaders(const EhdrType& ehdr) { |
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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_->ReadField(offset, &phdr, &phdr.p_type, sizeof(phdr.p_type))) { |
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return false; |
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} |
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if (HandleType(offset, phdr.p_type)) { |
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continue; |
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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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// Get the flags first, if this isn't an executable header, ignore it. |
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if (!memory_->ReadField(offset, &phdr, &phdr.p_flags, sizeof(phdr.p_flags))) { |
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return false; |
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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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if (!memory_->ReadField(offset, &phdr, &phdr.p_vaddr, sizeof(phdr.p_vaddr))) { |
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return false; |
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} |
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if (!memory_->ReadField(offset, &phdr, &phdr.p_offset, sizeof(phdr.p_offset))) { |
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return false; |
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} |
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if (!memory_->ReadField(offset, &phdr, &phdr.p_memsz, sizeof(phdr.p_memsz))) { |
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return false; |
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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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if (phdr.p_offset == 0) { |
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load_bias_ = phdr.p_vaddr; |
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} |
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break; |
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} |
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case PT_GNU_EH_FRAME: |
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if (!memory_->ReadField(offset, &phdr, &phdr.p_offset, sizeof(phdr.p_offset))) { |
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return false; |
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} |
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eh_frame_offset_ = phdr.p_offset; |
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if (!memory_->ReadField(offset, &phdr, &phdr.p_memsz, sizeof(phdr.p_memsz))) { |
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return false; |
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} |
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eh_frame_size_ = phdr.p_memsz; |
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break; |
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case PT_DYNAMIC: |
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if (!memory_->ReadField(offset, &phdr, &phdr.p_offset, sizeof(phdr.p_offset))) { |
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return false; |
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} |
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dynamic_offset_ = phdr.p_offset; |
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if (!memory_->ReadField(offset, &phdr, &phdr.p_memsz, sizeof(phdr.p_memsz))) { |
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return false; |
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} |
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dynamic_size_ = phdr.p_memsz; |
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break; |
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} |
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} |
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return true; |
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} |
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template <typename EhdrType, typename ShdrType> |
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bool ElfInterface::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_->ReadField(sh_offset, &shdr, &shdr.sh_offset, sizeof(shdr.sh_offset)) && |
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memory_->ReadField(sh_offset, &shdr, &shdr.sh_size, sizeof(shdr.sh_size))) { |
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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_->ReadField(offset, &shdr, &shdr.sh_type, sizeof(shdr.sh_type))) { |
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return false; |
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} |
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if (shdr.sh_type == SHT_SYMTAB || shdr.sh_type == SHT_DYNSYM) { |
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if (!memory_->Read(offset, &shdr, sizeof(shdr))) { |
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return false; |
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} |
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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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return false; |
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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_->ReadField(str_offset, &str_shdr, &str_shdr.sh_type, sizeof(str_shdr.sh_type))) { |
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return false; |
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} |
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if (str_shdr.sh_type != SHT_STRTAB) { |
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return false; |
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} |
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if (!memory_->ReadField(str_offset, &str_shdr, &str_shdr.sh_offset, |
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sizeof(str_shdr.sh_offset))) { |
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return false; |
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} |
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if (!memory_->ReadField(str_offset, &str_shdr, &str_shdr.sh_size, sizeof(str_shdr.sh_size))) { |
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return false; |
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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 (!memory_->ReadField(offset, &shdr, &shdr.sh_name, sizeof(shdr.sh_name))) { |
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return false; |
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} |
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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)) { |
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uint64_t* offset_ptr = nullptr; |
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uint64_t* size_ptr = nullptr; |
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if (name == ".debug_frame") { |
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offset_ptr = &debug_frame_offset_; |
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size_ptr = &debug_frame_size_; |
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} else if (name == ".gnu_debugdata") { |
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offset_ptr = &gnu_debugdata_offset_; |
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size_ptr = &gnu_debugdata_size_; |
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} |
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if (offset_ptr != nullptr && |
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memory_->ReadField(offset, &shdr, &shdr.sh_offset, sizeof(shdr.sh_offset)) && |
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memory_->ReadField(offset, &shdr, &shdr.sh_size, sizeof(shdr.sh_size))) { |
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*offset_ptr = shdr.sh_offset; |
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*size_ptr = 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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return true; |
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} |
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template <typename DynType> |
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bool ElfInterface::GetSonameWithTemplate(std::string* soname) { |
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if (soname_type_ == SONAME_INVALID) { |
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return false; |
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} |
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if (soname_type_ == SONAME_VALID) { |
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*soname = soname_; |
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return true; |
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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_offset = 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_size_; |
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for (uint64_t offset = dynamic_offset_; offset < max_offset; offset += sizeof(DynType)) { |
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if (!memory_->Read(offset, &dyn, sizeof(dyn))) { |
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return false; |
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} |
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if (dyn.d_tag == DT_STRTAB) { |
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strtab_offset = 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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soname_offset += strtab_offset; |
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if (soname_offset >= strtab_offset + strtab_size) { |
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return false; |
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} |
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if (!memory_->ReadString(soname_offset, &soname_)) { |
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return false; |
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} |
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soname_type_ = SONAME_VALID; |
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*soname = soname_; |
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return true; |
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} |
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template <typename SymType> |
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bool ElfInterface::GetFunctionNameWithTemplate(uint64_t addr, std::string* name, |
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uint64_t* func_offset) { |
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if (symbols_.empty()) { |
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return false; |
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} |
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for (const auto symbol : symbols_) { |
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if (symbol->GetName<SymType>(addr, load_bias_, memory_, name, func_offset)) { |
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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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bool ElfInterface::Step(uint64_t pc, Regs* regs, Memory* process_memory) { |
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// Need to subtract off the load_bias to get the correct pc. |
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if (pc < load_bias_) { |
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return false; |
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} |
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pc -= load_bias_; |
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// Try the eh_frame first. |
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DwarfSection* eh_frame = eh_frame_.get(); |
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if (eh_frame != nullptr && eh_frame->Step(pc, regs, process_memory)) { |
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return true; |
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} |
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// Try the debug_frame next. |
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DwarfSection* debug_frame = debug_frame_.get(); |
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if (debug_frame != nullptr && debug_frame->Step(pc, regs, process_memory)) { |
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return true; |
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} |
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return false; |
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} |
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// Instantiate all of the needed template functions. |
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template void ElfInterface::InitHeadersWithTemplate<uint32_t>(); |
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template void ElfInterface::InitHeadersWithTemplate<uint64_t>(); |
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template bool ElfInterface::ReadAllHeaders<Elf32_Ehdr, Elf32_Phdr, Elf32_Shdr>(); |
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template bool ElfInterface::ReadAllHeaders<Elf64_Ehdr, Elf64_Phdr, Elf64_Shdr>(); |
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template bool ElfInterface::ReadProgramHeaders<Elf32_Ehdr, Elf32_Phdr>(const Elf32_Ehdr&); |
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template bool ElfInterface::ReadProgramHeaders<Elf64_Ehdr, Elf64_Phdr>(const Elf64_Ehdr&); |
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template bool ElfInterface::ReadSectionHeaders<Elf32_Ehdr, Elf32_Shdr>(const Elf32_Ehdr&); |
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template bool ElfInterface::ReadSectionHeaders<Elf64_Ehdr, Elf64_Shdr>(const Elf64_Ehdr&); |
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template bool ElfInterface::GetSonameWithTemplate<Elf32_Dyn>(std::string*); |
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template bool ElfInterface::GetSonameWithTemplate<Elf64_Dyn>(std::string*); |
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template bool ElfInterface::GetFunctionNameWithTemplate<Elf32_Sym>(uint64_t, std::string*, |
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uint64_t*); |
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template bool ElfInterface::GetFunctionNameWithTemplate<Elf64_Sym>(uint64_t, std::string*, |
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uint64_t*); |
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} // namespace unwindstack
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