1    :  // Copyright 2013 Google Inc. All Rights Reserved.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  //
  15    :  // COFF relinker. Relinking can be seen as decomposing an input image,
  16    :  // applying a sequence of block graph transforms (some applied implicitly,
  17    :  // and others provided by the user), followed by a sequence of orderers
  18    :  // (again, some implicit, some provided by the user), laying out, and
  19    :  // writing a new image. CoffRelinker encapsulates this workflow.
  20    :  //
  21    :  // It is intended to be used as follows:
  22    :  //
  23    :  //   CoffRelinker relinker;
  24    :  //   relinker.set_input_path(...);  // Required.
  25    :  //   relinker.set_output_path(...);  // Required.
  26    :  //   relinker.Init();  // Check the return value!
  27    :  //
  28    :  //   // At this point, the following accessors are valid:
  29    :  //   relinker.input_image_file();
  30    :  //   relinker.input_image_layout();
  31    :  //   relinker.block_graph();
  32    :  //   relinker.headers_block();
  33    :  //
  34    :  //   relinker.AppendTransform(...);  // May be called repeatedly.
  35    :  //   relinker.AppendOrderer(...);  // May be called repeatedly.
  36    :  //
  37    :  //   relinker.Relink();  // Check the return value!
  38    :  
  39    :  #ifndef SYZYGY_PE_COFF_RELINKER_H_
  40    :  #define SYZYGY_PE_COFF_RELINKER_H_
  41    :  
  42    :  #include "syzygy/pe/coff_file.h"
  43    :  #include "syzygy/pe/coff_transform_policy.h"
  44    :  #include "syzygy/pe/pe_coff_relinker.h"
  45    :  
  46    :  namespace pe {
  47    :  
  48    :  // A transformation on a COFF image, decomposing an original image, applying
  49    :  // some transforms to it, generating the layout, and writing the new image
  50    :  // to disk.
  51    :  //
  52    :  // Creating a CoffRelinker and not changing its default configuration yields
  53    :  // an identity relinker that will produce a semantically identical image.
  54    :  //
  55    :  // The workflow is as follows:
  56    :  //
  57    :  // 1. The image is read and decomposed.
  58    :  // 2. The image is transformed:
  59    :  //    a) Transforms provided by the user are applied.
  60    :  //    d) CoffPrepareHeadersTransform is applied.
  61    :  // 3. The image is ordered by the user-specified orderers, or else by
  62    :  //    OriginalOrderer if none is given.
  63    :  // 4. CoffImageLayoutBuilder is used to convert the OrderedBlockGraph to an
  64    :  //    ImageLayout.
  65    :  // 5. The new image file is written.
  66    :  class CoffRelinker : public PECoffRelinker {
  67    :   public:
  68    :    // Construct a default CoffRelinker. Initialize properties to default
  69    :    // values.
  70    :    // @param transform_policy The policy that dictates how to apply transforms.
  71    :    explicit CoffRelinker(const CoffTransformPolicy* transform_policy);
  72    :  
  73    :    // @see RelinkerInterface::image_format()
  74  E :    virtual ImageFormat image_format() const override {
  75  E :      return BlockGraph::COFF_IMAGE;
  76  E :    }
  77    :  
  78    :    // Read and decompose the main input image, treated as a COFF file.
  79    :    //
  80    :    // @returns true on success, false otherwise.
  81    :    virtual bool Init() override;
  82    :  
  83    :    // After a successful call to Init(), apply transforms, followed by
  84    :    // orderers, then the resulting COFF file is written to the main output
  85    :    // path.
  86    :    //
  87    :    // @returns true on success, false otherwise.
  88    :    virtual bool Relink() override;
  89    :  
  90    :    // After a successful call to Init(), retrieve the original unmodified
  91    :    // COFF file reader.
  92    :    //
  93    :    // @returns the original COFF file reader.
  94  E :    const CoffFile& input_image_file() const { return input_image_file_; }
  95    :  
  96    :   private:
  97    :    // Check paths for existence and overwriting validity.
  98    :    //
  99    :    // @returns true on success, or false on failure.
 100    :    bool CheckPaths();
 101    :  
 102    :    // The original COFF file reader.
 103    :    CoffFile input_image_file_;
 104    :  
 105    :    DISALLOW_COPY_AND_ASSIGN(CoffRelinker);
 106    :  };
 107    :  
 108    :  }  // namespace pe
 109    :  
 110    :  #endif  // SYZYGY_PE_COFF_RELINKER_H_