courgette/patcher_x86_32.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 // This is the transformation for Windows X86 executables.
   6
   7 #ifndef COURGETTE_WIN32_X86_PATCHER_H_
   8 #define COURGETTE_WIN32_X86_PATCHER_H_
   9
  10 #include "courgette/ensemble.h"
  11
  12 namespace courgette {
  13
  14 // Courgette32X86Patcher is a TransformationPatcher for Windows 32-bit
  15 // executables.
  16 //
  17 class PatcherX86_32 : public TransformationPatcher {
  18  public:
  19   explicit PatcherX86_32(const Region& region)
  20       : ensemble_region_(region) {
  21   }
  22
  23   Status Init(SourceStream* parameter_stream) {
  24     if (!parameter_stream->ReadVarint32(&base_offset_))
  25       return C_BAD_TRANSFORM;
  26     if (!parameter_stream->ReadVarint32(&base_length_))
  27       return C_BAD_TRANSFORM;
  28
  29     if (base_offset_ > ensemble_region_.length())
  30       return C_BAD_TRANSFORM;
  31     if (base_length_ > ensemble_region_.length() - base_offset_)
  32       return C_BAD_TRANSFORM;
  33
  34     return C_OK;
  35   }
  36
  37   Status PredictTransformParameters(SinkStreamSet* predicted_parameters) {
  38     // No code needed to write an 'empty' predicted parameter set.
  39     return C_OK;
  40   }
  41
  42   Status Transform(SourceStreamSet* corrected_parameters,
  43                    SinkStreamSet* transformed_element) {
  44     Status status;
  45     if (!corrected_parameters->Empty())
  46       return C_GENERAL_ERROR;   // Don't expect any corrected parameters.
  47
  48     AssemblyProgram* program = NULL;
  49     status = ParseDetectedExecutable(ensemble_region_.start() + base_offset_,
  50                                      base_length_,
  51                                      &program);
  52     if (status != C_OK)
  53       return status;
  54
  55     EncodedProgram* encoded = NULL;
  56     status = Encode(program, &encoded);
  57     DeleteAssemblyProgram(program);
  58     if (status != C_OK)
  59       return status;
  60
  61     status = WriteEncodedProgram(encoded, transformed_element);
  62     DeleteEncodedProgram(encoded);
  63
  64     return status;
  65   }
  66
  67   Status Reform(SourceStreamSet* transformed_element,
  68                 SinkStream* reformed_element) {
  69     Status status;
  70     EncodedProgram* encoded_program = NULL;
  71     status = ReadEncodedProgram(transformed_element, &encoded_program);
  72     if (status != C_OK)
  73       return status;
  74
  75     status = Assemble(encoded_program, reformed_element);
  76     DeleteEncodedProgram(encoded_program);
  77     if (status != C_OK)
  78       return status;
  79
  80     return C_OK;
  81   }
  82
  83  private:
  84   Region ensemble_region_;
  85
  86   uint32 base_offset_;
  87   uint32 base_length_;
  88
  89   DISALLOW_COPY_AND_ASSIGN(PatcherX86_32);
  90 };
  91
  92 }  // namespace
  93 #endif  // COURGETTE_WIN32_X86_PATCHER_H_