1    :  // Copyright 2012 Google Inc.
   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    :  // Implements an all-static class that manages shadow memory for ASAN.
  16    :  #ifndef SYZYGY_AGENT_ASAN_ASAN_SHADOW_H_
  17    :  #define SYZYGY_AGENT_ASAN_ASAN_SHADOW_H_
  18    :  
  19    :  #include "base/basictypes.h"
  20    :  
  21  m :  namespace agent {
  22  m :  namespace asan {
  23    :  
  24    :  // An all-static class that manages the ASAN shadow memory.
  25  m :  class Shadow {
  26  m :   public:
  27    :    // Poisons @p size bytes starting at @p addr.
  28    :    // @pre addr + size mod 8 == 0.
  29  m :    static void Poison(const void* addr, size_t size);
  30    :  
  31    :    // Un-poisons @p size bytes starting at @p addr.
  32    :    // @pre addr mod 8 == 0 && size mod 8 == 0.
  33  m :    static void Unpoison(const void* addr, size_t size);
  34    :  
  35    :    // Returns true iff the byte at @p addr is not poisoned.
  36  m :    static bool IsAccessible(const void* addr);
  37    :  
  38  m :   private:
  39    :    // One shadow byte for every 8 bytes in a 4G address space.
  40  m :    static const size_t kShadowSize = 1 << (32 - 3);
  41  m :    static uint8 shadow_[kShadowSize];
  42  m :  };
  43    :  
  44  m :  }  // namespace asan
  45  m :  }  // namespace agent
  46    :  
  47    :  #endif  // SYZYGY_AGENT_ASAN_ASAN_SHADOW_H_