103 lines
3.4 KiB
C++
103 lines
3.4 KiB
C++
// Copyright 2018 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef COMPONENTS_ZUCCHINI_RELOC_ELF_H_
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#define COMPONENTS_ZUCCHINI_RELOC_ELF_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <vector>
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#include "base/numerics/safe_conversions.h"
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#include "components/zucchini/address_translator.h"
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#include "components/zucchini/buffer_view.h"
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#include "components/zucchini/image_utils.h"
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#include "components/zucchini/type_elf.h"
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#include "third_party/abseil-cpp/absl/types/optional.h"
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namespace zucchini {
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// Section dimensions for ELF files, to store relevant dimensions data from
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// Elf32_Shdr and Elf64_Shdr, while reducing code duplication from templates.
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struct SectionDimensionsElf {
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SectionDimensionsElf() = default;
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template <class Elf_Shdr>
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explicit SectionDimensionsElf(const Elf_Shdr& section)
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: region(BufferRegion{base::checked_cast<size_t>(section.sh_offset),
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base::checked_cast<size_t>(section.sh_size)}),
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entry_size(base::checked_cast<offset_t>(section.sh_entsize)) {}
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friend bool operator<(const SectionDimensionsElf& a,
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const SectionDimensionsElf& b) {
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return a.region.offset < b.region.offset;
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}
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friend bool operator<(offset_t offset, const SectionDimensionsElf& section) {
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return offset < section.region.offset;
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}
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BufferRegion region;
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offset_t entry_size; // Varies across REL / RELA sections.
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};
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// A Generator to visit all reloc structs located in [|lo|, |hi|) (excluding
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// truncated strct at |lo| but inlcuding truncated struct at |hi|), and emit
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// valid References with |rel_type|. This implements a nested loop unrolled into
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// a generator: the outer loop has |cur_section_dimensions_| visiting
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// |reloc_section_dims| (sorted by |region.offset|), and the inner loop has
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// |cursor_| visiting successive reloc structs within |cur_section_dimensions_|.
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class RelocReaderElf : public ReferenceReader {
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public:
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RelocReaderElf(
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ConstBufferView image,
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Bitness bitness,
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const std::vector<SectionDimensionsElf>& reloc_section_dimensions,
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uint32_t rel_type,
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offset_t lo,
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offset_t hi,
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const AddressTranslator& translator);
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~RelocReaderElf() override;
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// If |rel| contains |r_offset| for |rel_type_|, return the RVA. Otherwise
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// return |kInvalidRva|. These also handle Elf*_Rela, by using the fact that
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// Elf*_Rel is a prefix of Elf*_Rela.
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rva_t GetRelocationTarget(elf::Elf32_Rel rel) const;
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rva_t GetRelocationTarget(elf::Elf64_Rel rel) const;
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// ReferenceReader:
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absl::optional<Reference> GetNext() override;
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private:
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const ConstBufferView image_;
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const Bitness bitness_;
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const uint32_t rel_type_;
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const std::vector<SectionDimensionsElf>& reloc_section_dimensions_;
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std::vector<SectionDimensionsElf>::const_iterator cur_section_dimensions_;
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offset_t hi_;
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offset_t cursor_;
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AddressTranslator::RvaToOffsetCache target_rva_to_offset_;
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};
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class RelocWriterElf : public ReferenceWriter {
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public:
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RelocWriterElf(MutableBufferView image,
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Bitness bitness,
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const AddressTranslator& translator);
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~RelocWriterElf() override;
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// ReferenceWriter:
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void PutNext(Reference ref) override;
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private:
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MutableBufferView image_;
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const Bitness bitness_;
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AddressTranslator::OffsetToRvaCache target_offset_to_rva_;
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};
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} // namespace zucchini
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#endif // COMPONENTS_ZUCCHINI_RELOC_ELF_H_
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