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// Copyright (c) 2011 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 COURGETTE_DISASSEMBLER_H_
#define COURGETTE_DISASSEMBLER_H_
#include <stddef.h>
#include <stdint.h>
#include <vector>
#include "base/macros.h"
#include "courgette/courgette.h"
#include "courgette/image_utils.h"
namespace courgette {
class AssemblyProgram;
class Disassembler : public AddressTranslator {
public:
// Visitor/adaptor to translate RVA to target RVA for abs32.
class RvaVisitor_Abs32 : public VectorRvaVisitor<RVA> {
public:
RvaVisitor_Abs32(const std::vector<RVA>& rva_locations,
const AddressTranslator& translator);
~RvaVisitor_Abs32() override { }
// VectorRvaVisitor<RVA> interfaces.
RVA Get() const override;
private:
const AddressTranslator& translator_;
DISALLOW_COPY_AND_ASSIGN(RvaVisitor_Abs32);
};
// Visitor/adaptor to translate RVA to target RVA for rel32.
class RvaVisitor_Rel32 : public VectorRvaVisitor<RVA> {
public:
RvaVisitor_Rel32(const std::vector<RVA>& rva_locations,
const AddressTranslator& translator);
~RvaVisitor_Rel32() override { }
// VectorRvaVisitor<RVA> interfaces.
RVA Get() const override;
private:
const AddressTranslator& translator_;
DISALLOW_COPY_AND_ASSIGN(RvaVisitor_Rel32);
};
virtual ~Disassembler();
// AddressTranslator interfaces.
virtual RVA FileOffsetToRVA(FileOffset file_offset) const override = 0;
virtual FileOffset RVAToFileOffset(RVA rva) const override = 0;
const uint8_t* FileOffsetToPointer(FileOffset file_offset) const override;
const uint8_t* RVAToPointer(RVA rva) const override;
RVA PointerToTargetRVA(const uint8_t* p) const = 0;
virtual ExecutableType kind() const = 0;
// Returns a caller-owned new RvaVisitor to iterate through abs32 target RVAs.
virtual RvaVisitor* CreateAbs32TargetRvaVisitor() = 0;
// Returns a caller-owned new RvaVisitor to iterate through rel32 target RVAs.
virtual RvaVisitor* CreateRel32TargetRvaVisitor() = 0;
// Removes unused rel32 locations (architecture-specific). This is needed
// because we may remove rel32 Labels along the way. As a result the matching
// matching rel32 addresses become unused. Removing them saves space.
virtual void RemoveUnusedRel32Locations(AssemblyProgram* program) = 0;
// Returns true if the buffer appears to be a valid executable of the expected
// type, and false otherwise. This needs not be called before Disassemble().
virtual bool ParseHeader() = 0;
// Disassembles the item passed to the factory method into the output
// parameter 'program'.
virtual bool Disassemble(AssemblyProgram* program) = 0;
// ok() may always be called but returns true only after ParseHeader()
// succeeds.
bool ok() const { return failure_reason_ == nullptr; }
// Returns the length of the image. May reduce after ParseHeader().
size_t length() const { return length_; }
const uint8_t* start() const { return start_; }
const uint8_t* end() const { return end_; }
protected:
Disassembler(const void* start, size_t length);
bool Good();
bool Bad(const char *reason);
// Returns true if the array lies within our memory region.
bool IsArrayInBounds(size_t offset, size_t elements, size_t element_size) {
return offset <= length() && elements <= (length() - offset) / element_size;
}
// Computes and stores all Labels before scanning program bytes.
void PrecomputeLabels(AssemblyProgram* program);
// Reduce the length of the image in memory. Does not actually free
// (or realloc) any memory. Usually only called via ParseHeader().
void ReduceLength(size_t reduced_length);
private:
const char* failure_reason_;
//
// Basic information that is always valid after construction, although
// ParseHeader() may shorten |length_| if the executable is shorter than the
// total data.
//
size_t length_; // In current memory.
const uint8_t* start_; // In current memory, base for 'file offsets'.
const uint8_t* end_; // In current memory.
DISALLOW_COPY_AND_ASSIGN(Disassembler);
};
} // namespace courgette
#endif // COURGETTE_DISASSEMBLER_H_