courgette/encoded_program.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COURGETTE_ENCODED_PROGRAM_H_
   6 #define COURGETTE_ENCODED_PROGRAM_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "courgette/disassembler.h"
  12 #include "courgette/memory_allocator.h"
  13
  14 namespace courgette {
  15
  16 class SinkStream;
  17 class SinkStreamSet;
  18 class SourceStreamSet;
  19
  20 // An EncodedProgram is a set of tables that contain a simple 'binary assembly
  21 // language' that can be assembled to produce a sequence of bytes, for example,
  22 // a Windows 32-bit executable.
  23 //
  24 class EncodedProgram {
  25  public:
  26   EncodedProgram();
  27   ~EncodedProgram();
  28
  29   // Generating an EncodedProgram:
  30   //
  31   // (1) The image base can be specified at any time.
  32   void set_image_base(uint64 base) { image_base_ = base; }
  33
  34   // (2) Address tables and indexes defined first.
  35   CheckBool DefineRel32Label(int index, RVA address) WARN_UNUSED_RESULT;
  36   CheckBool DefineAbs32Label(int index, RVA address) WARN_UNUSED_RESULT;
  37   void EndLabels();
  38
  39   // (3) Add instructions in the order needed to generate bytes of file.
  40   // NOTE: If any of these methods ever fail, the EncodedProgram instance
  41   // has failed and should be discarded.
  42   CheckBool AddOrigin(RVA rva) WARN_UNUSED_RESULT;
  43   CheckBool AddCopy(uint32 count, const void* bytes) WARN_UNUSED_RESULT;
  44   CheckBool AddRel32(int label_index) WARN_UNUSED_RESULT;
  45   CheckBool AddAbs32(int label_index) WARN_UNUSED_RESULT;
  46   CheckBool AddPeMakeRelocs() WARN_UNUSED_RESULT;
  47   CheckBool AddElfMakeRelocs() WARN_UNUSED_RESULT;
  48
  49   // (3) Serialize binary assembly language tables to a set of streams.
  50   CheckBool WriteTo(SinkStreamSet* streams) WARN_UNUSED_RESULT;
  51
  52   // Using an EncodedProgram to generate a byte stream:
  53   //
  54   // (4) Deserializes a fresh EncodedProgram from a set of streams.
  55   bool ReadFrom(SourceStreamSet* streams);
  56
  57   // (5) Assembles the 'binary assembly language' into final file.
  58   CheckBool AssembleTo(SinkStream* buffer) WARN_UNUSED_RESULT;
  59
  60  private:
  61   // Binary assembly language operations.
  62   // These are part of the patch format. Reusing an existing value will
  63   // break backwards compatibility.
  64   enum OP {
  65     ORIGIN = 0,    // ORIGIN <rva> - set address for subsequent assembly.
  66     COPY = 1,      // COPY <count> <bytes> - copy bytes to output.
  67     COPY1 = 2,     // COPY1 <byte> - same as COPY 1 <byte>.
  68     REL32 = 3,     // REL32 <index> - emit rel32 encoded reference to address at
  69                    // address table offset <index>
  70     ABS32 = 4,     // ABS32 <index> - emit abs32 encoded reference to address at
  71                    // address table offset <index>
  72     MAKE_PE_RELOCATION_TABLE = 5,  // Emit PE base relocation table blocks.
  73     MAKE_ELF_RELOCATION_TABLE = 6, // Emit Elf relocation table.
  74   };
  75
  76   typedef NoThrowBuffer<RVA> RvaVector;
  77   typedef NoThrowBuffer<uint32> UInt32Vector;
  78   typedef NoThrowBuffer<uint8> UInt8Vector;
  79   typedef NoThrowBuffer<OP> OPVector;
  80
  81   void DebuggingSummary();
  82   CheckBool GeneratePeRelocations(SinkStream *buffer) WARN_UNUSED_RESULT;
  83   CheckBool GenerateElfRelocations(SinkStream *buffer) WARN_UNUSED_RESULT;
  84   CheckBool DefineLabelCommon(RvaVector*, int, RVA) WARN_UNUSED_RESULT;
  85   void FinishLabelsCommon(RvaVector* addresses);
  86
  87   // Binary assembly language tables.
  88   uint64 image_base_;
  89   RvaVector rel32_rva_;
  90   RvaVector abs32_rva_;
  91   OPVector ops_;
  92   RvaVector origins_;
  93   UInt32Vector copy_counts_;
  94   UInt8Vector copy_bytes_;
  95   UInt32Vector rel32_ix_;
  96   UInt32Vector abs32_ix_;
  97
  98   // Table of the addresses containing abs32 relocations; computed during
  99   // assembly, used to generate base relocation table.
 100   UInt32Vector abs32_relocs_;
 101
 102   DISALLOW_COPY_AND_ASSIGN(EncodedProgram);
 103 };
 104
 105 }  // namespace courgette
 106 #endif  // COURGETTE_ENCODED_PROGRAM_H_