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// 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.
#include <stddef.h>
#include <stdint.h>
#include <vector>
#include "base/macros.h"
#include "base/optional.h"
#include "components/zucchini/address_translator.h"
#include "components/zucchini/buffer_view.h"
#include "components/zucchini/image_utils.h"
namespace zucchini {
// A class to represent an abs32 address (32-bit or 64-bit). Accessors are
// provided to translate from / to RVA, and to read / write the represented
// abs32 address from / to an image.
class AbsoluteAddress {
AbsoluteAddress(Bitness bitness, uint64_t image_base);
// Attempts to translate |rva| to an abs32 address. On success, assigns
// |value_| to the result and returns true. On failure (invalid |rva| or
// overflow), returns false.
bool FromRva(rva_t rva);
// Returns the RVA for |value_|, or |kInvalidRva| if the represented value
// address does not correspond to a valid RVA.
rva_t ToRva() const;
// Attempts to read the abs32 address at |image[offset]| into |value_|. On
// success, updates |value_| and returns true. On failure (invalid |offset|),
// returns false.
bool Read(offset_t offset, const ConstBufferView& image);
// Attempts to write |value_| to to |(*image)[offset]|. On success, performs
// the write and returns true. On failure (invalid |offset|), returns false.
bool Write(offset_t offset, MutableBufferView* image);
uint32_t width() const { return WidthOf(bitness_); }
// Exposing |value_| for testing.
uint64_t* mutable_value() { return &value_; }
const Bitness bitness_;
const uint64_t image_base_; // Accommodates 32-bit and 64-bit.
uint64_t value_; // Accommodates 32-bit and 64-bit.
// A class to extract Win32 abs32 references from |abs32_locations| within
// |image_| bounded by |[lo, hi)|. GetNext() is used to successively return
// data as Units, which are locations and (potentially out-of-bound) RVAs.
// |addr| determines the bitness of abs32 values stored, and mediates all reads.
class Abs32RvaExtractorWin32 {
struct Unit {
offset_t location;
rva_t target_rva;
// Requires |lo| <= |hi|, and they must not straddle a reference body (with
// length |addr.width()|) in |abs32_locations|.
Abs32RvaExtractorWin32(ConstBufferView image,
AbsoluteAddress&& addr,
const std::vector<offset_t>& abs32_locations,
offset_t lo,
offset_t hi);
// Visits given abs32 locations, rejects invalid locations and non-existent
// RVAs, and returns reference as Unit, or base::nullopt on completion.
base::Optional<Unit> GetNext();
ConstBufferView image_;
AbsoluteAddress addr_;
std::vector<offset_t>::const_iterator cur_abs32_;
std::vector<offset_t>::const_iterator end_abs32_;
// A reader for Win32 abs32 references that filters and translates results from
// |abs32_rva_extractor_|.
class Abs32ReaderWin32 : public ReferenceReader {
Abs32ReaderWin32(Abs32RvaExtractorWin32&& abs32_rva_extractor,
const AddressTranslator& translator);
~Abs32ReaderWin32() override;
// ReferenceReader:
base::Optional<Reference> GetNext() override;
Abs32RvaExtractorWin32 abs32_rva_extractor_;
AddressTranslator::RvaToOffsetCache target_rva_to_offset_;
// A writer for Win32 abs32 references. |addr| determines the bitness of the
// abs32 values stored, and mediates all writes.
class Abs32WriterWin32 : public ReferenceWriter {
Abs32WriterWin32(MutableBufferView image,
AbsoluteAddress&& addr,
const AddressTranslator& translator);
~Abs32WriterWin32() override;
// ReferenceWriter:
void PutNext(Reference ref) override;
MutableBufferView image_;
AbsoluteAddress addr_;
AddressTranslator::OffsetToRvaCache target_offset_to_rva_;
// Given a list of abs32 |locations|, removes all elements whose targets cannot
// be translated. Returns the number of elements removed.
size_t RemoveUntranslatableAbs32(ConstBufferView image,
AbsoluteAddress&& addr,
const AddressTranslator& translator,
std::vector<offset_t>* locations);
// Given a sorted list of abs32 |locations|, removes all elements whose body
// (with |width| given) overlaps with the body of a previous element.
size_t RemoveOverlappingAbs32Locations(uint32_t width,
std::vector<offset_t>* locations);
} // namespace zucchini