mojo/system/memory.cc

   1 // Copyright 2013 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 #include "mojo/system/memory.h"
   6
   7 #include <limits>
   8
   9 #include "base/logging.h"
  10
  11 namespace mojo {
  12 namespace system {
  13
  14 template <size_t size>
  15 bool VerifyUserPointerForSize(const void* pointer, size_t count) {
  16   if (count > std::numeric_limits<size_t>::max() / size)
  17     return false;
  18
  19   // TODO(vtl): If running in kernel mode, do a full verification. For now, just
  20   // check that it's non-null if |size| is nonzero. (A faster user mode
  21   // implementation is also possible if this check is skipped.)
  22   return count == 0 || !!pointer;
  23 }
  24
  25 // Explicitly instantiate the sizes we need. Add instantiations as needed.
  26 template MOJO_SYSTEM_IMPL_EXPORT bool VerifyUserPointerForSize<1>(
  27     const void*, size_t);
  28 template MOJO_SYSTEM_IMPL_EXPORT bool VerifyUserPointerForSize<4>(
  29     const void*, size_t);
  30 template MOJO_SYSTEM_IMPL_EXPORT bool VerifyUserPointerForSize<8>(
  31     const void*, size_t);
  32
  33 }  // namespace system
  34 }  // namespace mojo