| //===-- Decompressor.cpp --------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Object/Decompressor.h" |
| #include "llvm/BinaryFormat/ELF.h" |
| #include "llvm/Object/ObjectFile.h" |
| #include "llvm/Support/Compression.h" |
| #include "llvm/Support/DataExtractor.h" |
| #include "llvm/Support/Endian.h" |
| |
| using namespace llvm; |
| using namespace llvm::support::endian; |
| using namespace object; |
| |
| Expected<Decompressor> Decompressor::create(StringRef Name, StringRef Data, |
| bool IsLE, bool Is64Bit) { |
| if (!compression::zlib::isAvailable()) |
| return createError("zlib is not available"); |
| |
| Decompressor D(Data); |
| if (Error Err = D.consumeCompressedZLibHeader(Is64Bit, IsLE)) |
| return std::move(Err); |
| return D; |
| } |
| |
| Decompressor::Decompressor(StringRef Data) |
| : SectionData(Data), DecompressedSize(0) {} |
| |
| Error Decompressor::consumeCompressedZLibHeader(bool Is64Bit, |
| bool IsLittleEndian) { |
| using namespace ELF; |
| uint64_t HdrSize = Is64Bit ? sizeof(Elf64_Chdr) : sizeof(Elf32_Chdr); |
| if (SectionData.size() < HdrSize) |
| return createError("corrupted compressed section header"); |
| |
| DataExtractor Extractor(SectionData, IsLittleEndian, 0); |
| uint64_t Offset = 0; |
| if (Extractor.getUnsigned(&Offset, Is64Bit ? sizeof(Elf64_Word) |
| : sizeof(Elf32_Word)) != |
| ELFCOMPRESS_ZLIB) |
| return createError("unsupported compression type"); |
| |
| // Skip Elf64_Chdr::ch_reserved field. |
| if (Is64Bit) |
| Offset += sizeof(Elf64_Word); |
| |
| DecompressedSize = Extractor.getUnsigned( |
| &Offset, Is64Bit ? sizeof(Elf64_Xword) : sizeof(Elf32_Word)); |
| SectionData = SectionData.substr(HdrSize); |
| return Error::success(); |
| } |
| |
| Error Decompressor::decompress(MutableArrayRef<uint8_t> Buffer) { |
| size_t Size = Buffer.size(); |
| return compression::zlib::uncompress(arrayRefFromStringRef(SectionData), |
| Buffer.data(), Size); |
| } |