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 #include "build/build_config.h" 11 12 namespace mojo { 13 namespace system { 14 namespace internal { 15 16 template <size_t alignment> 17 bool IsAligned(const void* pointer) { 18 return reinterpret_cast<uintptr_t>(pointer) % alignment == 0; 19 } 20 21 // MSVS (2010, 2013) sometimes (on the stack) aligns, e.g., |int64_t|s (for 22 // which |__alignof(int64_t)| is 8) to 4-byte boundaries. http://goo.gl/Y2n56T 23 #if defined(COMPILER_MSVC) && defined(ARCH_CPU_32_BITS) 24 template <> 25 bool IsAligned<8>(const void* pointer) { 26 return reinterpret_cast<uintptr_t>(pointer) % 4 == 0; 27 } 28 #endif 29 30 template <size_t size, size_t alignment> 31 void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer(const void* pointer) { 32 CHECK(pointer && IsAligned<alignment>(pointer)); 33 } 34 35 // Explicitly instantiate the sizes we need. Add instantiations as needed. 36 template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<1, 1>(const void*); 37 template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<4, 4>(const void*); 38 template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<8, 4>(const void*); 39 template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<8, 8>(const void*); 40 41 template <size_t size, size_t alignment> 42 void MOJO_SYSTEM_IMPL_EXPORT 43 CheckUserPointerWithCount(const void* pointer, size_t count) { 44 CHECK_LE(count, std::numeric_limits<size_t>::max() / size); 45 CHECK(count == 0 || (pointer && IsAligned<alignment>(pointer))); 46 } 47 48 // Explicitly instantiate the sizes we need. Add instantiations as needed. 49 template void MOJO_SYSTEM_IMPL_EXPORT 50 CheckUserPointerWithCount<1, 1>(const void*, size_t); 51 template void MOJO_SYSTEM_IMPL_EXPORT 52 CheckUserPointerWithCount<4, 4>(const void*, size_t); 53 template void MOJO_SYSTEM_IMPL_EXPORT 54 CheckUserPointerWithCount<8, 4>(const void*, size_t); 55 template void MOJO_SYSTEM_IMPL_EXPORT 56 CheckUserPointerWithCount<8, 8>(const void*, size_t); 57 58 template <size_t alignment> 59 void CheckUserPointerWithSize(const void* pointer, size_t size) { 60 // TODO(vtl): If running in kernel mode, do a full verification. For now, just 61 // check that it's non-null and aligned. (A faster user mode implementation is 62 // also possible if this check is skipped.) 63 CHECK(size == 0 || (!!pointer && internal::IsAligned<alignment>(pointer))); 64 } 65 66 // Explicitly instantiate the sizes we need. Add instantiations as needed. 67 template void MOJO_SYSTEM_IMPL_EXPORT 68 CheckUserPointerWithSize<1>(const void*, size_t); 69 template void MOJO_SYSTEM_IMPL_EXPORT 70 CheckUserPointerWithSize<4>(const void*, size_t); 71 // Whereas the other |Check...()| functions are usually used with integral typs 72 // or arrays of integral types, this one is used with Options structs for which 73 // alignment has been explicitly been specified (using |MOJO_ALIGNAS()|), which 74 // MSVS *does* respect. 75 #if defined(COMPILER_MSVC) && defined(ARCH_CPU_32_BITS) 76 template <> 77 void MOJO_SYSTEM_IMPL_EXPORT 78 CheckUserPointerWithSize<8>(const void* pointer, size_t size) { 79 CHECK(size == 0 || 80 (!!pointer && reinterpret_cast<uintptr_t>(pointer) % 8 == 0)); 81 } 82 #else 83 template void MOJO_SYSTEM_IMPL_EXPORT 84 CheckUserPointerWithSize<8>(const void*, size_t); 85 #endif 86 87 } // namespace internal 88 } // namespace system 89 } // namespace mojo 90
