1    :  // Copyright 2012 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    :  #include "syzygy/pe/transforms/add_metadata_transform.h"
  16    :  
  17    :  #include "syzygy/block_graph/typed_block.h"
  18    :  #include "syzygy/common/defs.h"
  19    :  #include "syzygy/pe/metadata.h"
  20    :  #include "syzygy/pe/pe_file.h"
  21    :  #include "syzygy/pe/pe_utils.h"
  22    :  
  23    :  namespace pe {
  24    :  namespace transforms {
  25    :  
  26    :  const char AddMetadataTransform::kTransformName[] =
  27    :      "AddMetadataTransform";
  28    :  
  29    :  AddMetadataTransform::AddMetadataTransform(const base::FilePath& module_path)
  30  E :      : module_path_(module_path) {
  31  E :  }
  32    :  
  33    :  bool AddMetadataTransform::TransformBlockGraph(
  34    :      const TransformPolicyInterface* policy,
  35    :      BlockGraph* block_graph,
  36  E :      BlockGraph::Block* /*dos_header_block*/) {
  37  E :    DCHECK(policy != NULL);
  38  E :    DCHECK(block_graph != NULL);
  39    :  
  40  E :    metadata_block_ = NULL;
  41    :  
  42  E :    pe::PEFile pe_file;
  43  E :    if (!pe_file.Init(module_path_)) {
  44  i :      LOG(ERROR) << "Unable to initialize PEFile for module \""
  45    :                 << module_path_.value() << "\".";
  46  i :      return false;
  47    :    }
  48    :  
  49  E :    pe::PEFile::Signature pe_signature;
  50  E :    pe_file.GetSignature(&pe_signature);
  51    :  
  52  E :    pe::Metadata metadata;
  53  E :    if (!metadata.Init(pe_signature)) {
  54  i :      LOG(ERROR) << "Unable to initialize metadata.";
  55  i :      return false;
  56    :    }
  57    :  
  58  E :    const BlockGraph::Section* section = NULL;
  59  E :    BlockGraph::Block* block = NULL;
  60    :  
  61    :    // Look for the section.
  62  E :    section = block_graph->FindSection(common::kSyzygyMetadataSectionName);
  63    :  
  64    :    // If we found the section then look for the block.
  65  E :    if (section != NULL) {
  66    :      BlockGraph::BlockMap::iterator block_it =
  67  E :          block_graph->blocks_mutable().begin();
  68  E :      for (; block_it != block_graph->blocks_mutable().end(); ++block_it) {
  69  E :        if (block_it->second.section() == section->id()) {
  70    :          // We reuse the first metadata block we find, but we shouldn't find
  71    :          // any others.
  72  E :          if (block != NULL) {
  73  E :            LOG(ERROR) << "Found multiple metadata blocks.";
  74  E :            return false;
  75    :          }
  76  E :          block = &block_it->second;
  77    :        }
  78  E :      }
  79    :    } else {
  80    :      // Otherwise, create the section.
  81    :      section = block_graph->AddSection(common::kSyzygyMetadataSectionName,
  82  E :                                        kReadOnlyDataCharacteristics);
  83  E :      DCHECK(section != NULL);
  84    :    }
  85    :  
  86    :    // If no block was found, create one.
  87  E :    if (block == NULL) {
  88  E :      block = block_graph->AddBlock(BlockGraph::DATA_BLOCK, 0, "Metadata");
  89  E :      block->set_section(section->id());
  90    :    }
  91  E :    DCHECK(block != NULL);
  92    :  
  93    :    // Fill in the metadata block.
  94  E :    if (!metadata.SaveToBlock(block)) {
  95  i :      LOG(ERROR) << "Unable to create metadata block.";
  96  i :      return false;
  97    :    }
  98    :  
  99  E :    metadata_block_ = block;
 100    :  
 101  E :    return true;
 102  E :  }
 103    :  
 104    :  }  // namespace transforms
 105    :  }  // namespace pe