1    :  // Copyright 2015 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    :  // The main class of the hot patching Asan runtime library.
  16    :  //
  17    :  // A single instance of this class is created by the DllMain of module of
  18    :  // the hot patching Asan runtime library and can be accessed from anywhere
  19    :  // via |HotPatchingAsanRuntime::runtime()|.
  20    :  
  21    :  #ifndef SYZYGY_AGENT_ASAN_HOT_PATCHING_ASAN_RUNTIME_H_
  22    :  #define SYZYGY_AGENT_ASAN_HOT_PATCHING_ASAN_RUNTIME_H_
  23    :  
  24    :  #include <windows.h>
  25    :  #include <string>
  26    :  #include <unordered_set>
  27    :  
  28    :  #include "base/logging.h"
  29    :  #include "base/memory/scoped_ptr.h"
  30    :  #include "base/memory/singleton.h"
  31    :  #include "syzygy/agent/common/entry_frame.h"
  32    :  
  33    :  namespace agent {
  34    :  namespace asan {
  35    :  
  36    :  class AsanLogger;
  37    :  
  38    :  class HotPatchingAsanRuntime {
  39    :   public:
  40    :    // Hot patching Asan transform instruments the entry point of the modules so
  41    :    // that this function is called before each DllMain call of the instrumented
  42    :    // modules. At this point the code of the hot patching runtime module is
  43    :    // already loaded so, this is a good place to do hot patching.
  44    :    // @param entry_frame A frame containing the return address and the parameters
  45    :    //     of the original DllMain function.
  46    :    static void WINAPI DllMainEntryHook(agent::EntryFrame* entry_frame,
  47    :                                        FuncAddr function);
  48    :  
  49    :    // Access to the singleton class.
  50    :    // @returns the hot patching Asan runtime.
  51    :    static HotPatchingAsanRuntime* GetInstance() {
  52    :      return base::Singleton<HotPatchingAsanRuntime>::get();
  53    :    }
  54    :  
  55    :    // Activates the hot patching Asan mode on a given module.
  56    :    // @param instance The handle to the module.
  57    :    // NOTE: The current implementation of this function is not thread-safe. This
  58    :    //     is not a problem for now, because we call this function under the
  59    :    //     loader lock.
  60    :    bool HotPatch(HINSTANCE instance);
  61    :  
  62    :    // Sets up the hot patching Asan runtime.
  63    :    void SetUp();
  64    :  
  65    :    // Gets the set of modules that have already been hot patched.
  66    :    // @returns a set containing the handles of the hot patched modules.
  67  E :    const std::unordered_set<HMODULE>& hot_patched_modules() {
  68  E :      return hot_patched_modules_;
  69  E :    }
  70    :  
  71    :    // Gets a logger.
  72    :    AsanLogger* logger() {
  73    :      DCHECK_NE(static_cast<AsanLogger*>(nullptr), logger_.get());
  74    :      return logger_.get();
  75    :    }
  76    :  
  77    :   protected:
  78    :    void SetUpLogger();
  79    :  
  80    :    // The shared logger instance that will be used to report errors and runtime
  81    :    // information.
  82    :    scoped_ptr<AsanLogger> logger_;
  83    :  
  84    :    // Set of modules that have already been hot patched. We don't want to hot
  85    :    // patch the same module twice.
  86    :    std::unordered_set<HMODULE> hot_patched_modules_;
  87    :  
  88    :   private:
  89    :    friend struct base::DefaultSingletonTraits<HotPatchingAsanRuntime>;
  90    :    friend class HotPatchingAsanRuntimeTest;
  91    :  
  92    :    HotPatchingAsanRuntime();
  93    :    ~HotPatchingAsanRuntime();
  94    :  
  95    :    DISALLOW_COPY_AND_ASSIGN(HotPatchingAsanRuntime);
  96    :  };
  97    :  
  98    :  }  // namespace asan
  99    :  }  // namespace agent
 100    :  
 101    :  extern "C" {
 102    :  
 103    :  // Exposes the hot patching Asan runtime to the unittests.
 104    :  // @returns the runtime instance.
 105    :  agent::asan::HotPatchingAsanRuntime* hp_asan_GetActiveHotPatchingAsanRuntime();
 106    :  
 107    :  }
 108    :  
 109    :  #endif  // SYZYGY_AGENT_ASAN_HOT_PATCHING_ASAN_RUNTIME_H_