courgette/win32_x86_patcher.h

   1 // Copyright (c) 2009 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 // CourgetteWin32X86Patcher is a TransformationPatcher for Windows 32-bit
  15 // executables.
  16 //
  17 class CourgetteWin32X86Patcher : public TransformationPatcher {
  18  public:
  19   explicit CourgetteWin32X86Patcher(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 = ParseWin32X86PE(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     if (status != C_OK)
  64       return status;
  65
  66     return status;
  67   }
  68
  69   Status Reform(SourceStreamSet* transformed_element,
  70                 SinkStream* reformed_element) {
  71     Status status;
  72     EncodedProgram* encoded_program = NULL;
  73     status = ReadEncodedProgram(transformed_element, &encoded_program);
  74     if (status != C_OK)
  75       return status;
  76
  77     status = Assemble(encoded_program, reformed_element);
  78     DeleteEncodedProgram(encoded_program);
  79     if (status != C_OK)
  80       return status;
  81
  82     return C_OK;
  83   }
  84
  85  private:
  86   Region ensemble_region_;
  87
  88   uint32 base_offset_;
  89   uint32 base_length_;
  90
  91   DISALLOW_COPY_AND_ASSIGN(CourgetteWin32X86Patcher);
  92 };
  93
  94 }  // namespace
  95 #endif  // COURGETTE_WIN32_X86_PATCHER_H_