123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140 |
- // Copyright 2017 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef COMPONENTS_ZUCCHINI_RELOC_WIN32_H_
- #define COMPONENTS_ZUCCHINI_RELOC_WIN32_H_
- #include <stddef.h>
- #include <stdint.h>
- #include <vector>
- #include "components/zucchini/address_translator.h"
- #include "components/zucchini/buffer_source.h"
- #include "components/zucchini/buffer_view.h"
- #include "components/zucchini/image_utils.h"
- #include "third_party/abseil-cpp/absl/types/optional.h"
- namespace zucchini {
- // Win32 PE relocation table stores a list of (type, RVA) pairs. The table is
- // organized into "blocks" for RVAs with common high-order bits (12-31). Each
- // block consists of a list (even length) of 2-byte "units". Each unit stores
- // type (in bits 12-15) and low-order bits (0-11) of an RVA (in bits 0-11). In
- // pseudo-struct:
- // struct Block {
- // uint32_t rva_hi;
- // uint32_t block_size_in_bytes; // 8 + multiple of 4.
- // struct {
- // uint16_t rva_lo:12, type:4; // Little-endian.
- // } units[(block_size_in_bytes - 8) / 2]; // Size must be even.
- // } reloc_table[num_blocks]; // May have padding (type = 0).
- // Extracted Win32 reloc Unit data.
- struct RelocUnitWin32 {
- RelocUnitWin32();
- RelocUnitWin32(uint8_t type_in, offset_t location_in, rva_t target_rva_in);
- friend bool operator==(const RelocUnitWin32& a, const RelocUnitWin32& b);
- uint8_t type;
- offset_t location;
- rva_t target_rva;
- };
- // A reader that parses Win32 PE relocation data and emits RelocUnitWin32 for
- // each reloc unit that lies strictly inside |[lo, hi)|.
- class RelocRvaReaderWin32 {
- public:
- enum : ptrdiff_t { kRelocUnitSize = sizeof(uint16_t) };
- // Parses |image| at |reloc_region| to find beginning offsets of each reloc
- // block. On success, writes the result to |reloc_block_offsets| and returns
- // true. Otherwise leaves |reloc_block_offsets| in an undetermined state, and
- // returns false.
- static bool FindRelocBlocks(ConstBufferView image,
- BufferRegion reloc_region,
- std::vector<offset_t>* reloc_block_offsets);
- // |reloc_block_offsets| should be precomputed from FindRelBlocks().
- RelocRvaReaderWin32(ConstBufferView image,
- BufferRegion reloc_region,
- const std::vector<offset_t>& reloc_block_offsets,
- offset_t lo,
- offset_t hi);
- RelocRvaReaderWin32(RelocRvaReaderWin32&&);
- ~RelocRvaReaderWin32();
- // Successively visits and returns data for each reloc unit, or absl::nullopt
- // when all reloc units are found. Encapsulates block transition details.
- absl::optional<RelocUnitWin32> GetNext();
- private:
- // Assuming that |block_begin| points to the beginning of a reloc block, loads
- // |rva_hi_bits_| and assigns |cur_reloc_units_| as the region containing the
- // associated units, potentially truncated by |end_it_|. Returns true if reloc
- // data are available for read, and false otherwise.
- bool LoadRelocBlock(ConstBufferView::const_iterator block_begin);
- const ConstBufferView image_;
- // End iterator.
- ConstBufferView::const_iterator end_it_;
- // Unit data of the current reloc block.
- BufferSource cur_reloc_units_;
- // High-order bits (12-31) for all relocs of the current reloc block.
- rva_t rva_hi_bits_;
- };
- // A reader for Win32 reloc References, implemented as a filtering and
- // translation adaptor of RelocRvaReaderWin32.
- class RelocReaderWin32 : public ReferenceReader {
- public:
- // Takes ownership of |reloc_rva_reader|. |offset_bound| specifies the
- // exclusive upper bound of reloc target offsets, taking account of widths of
- // targets (which are abs32 References).
- RelocReaderWin32(RelocRvaReaderWin32&& reloc_rva_reader,
- uint16_t reloc_type,
- offset_t offset_bound,
- const AddressTranslator& translator);
- ~RelocReaderWin32() override;
- // ReferenceReader:
- absl::optional<Reference> GetNext() override;
- private:
- RelocRvaReaderWin32 reloc_rva_reader_;
- const uint16_t reloc_type_; // uint16_t to simplify shifting (<< 12).
- const offset_t offset_bound_;
- AddressTranslator::RvaToOffsetCache entry_rva_to_offset_;
- };
- // A writer for Win32 reloc References. This is simpler than the reader since:
- // - No iteration is required.
- // - High-order bits of reloc target RVAs are assumed to be handled elsewhere,
- // so only low-order bits need to be written.
- class RelocWriterWin32 : public ReferenceWriter {
- public:
- RelocWriterWin32(uint16_t reloc_type,
- MutableBufferView image,
- BufferRegion reloc_region,
- const std::vector<offset_t>& reloc_block_offsets,
- const AddressTranslator& translator);
- ~RelocWriterWin32() override;
- // ReferenceWriter:
- void PutNext(Reference ref) override;
- private:
- const uint16_t reloc_type_;
- MutableBufferView image_;
- BufferRegion reloc_region_;
- const std::vector<offset_t>& reloc_block_offsets_;
- AddressTranslator::OffsetToRvaCache target_offset_to_rva_;
- };
- } // namespace zucchini
- #endif // COMPONENTS_ZUCCHINI_RELOC_WIN32_H_
|