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90 lines
3.3 KiB
C++
90 lines
3.3 KiB
C++
// Copyright 2013 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "mojo/edk/system/memory.h"
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#include <limits>
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#include "base/logging.h"
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#include "build/build_config.h"
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namespace mojo {
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namespace system {
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namespace internal {
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template <size_t alignment>
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bool IsAligned(const void* pointer) {
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return reinterpret_cast<uintptr_t>(pointer) % alignment == 0;
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}
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// MSVS (2010, 2013) sometimes (on the stack) aligns, e.g., |int64_t|s (for
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// which |__alignof(int64_t)| is 8) to 4-byte boundaries. http://goo.gl/Y2n56T
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#if defined(COMPILER_MSVC) && defined(ARCH_CPU_32_BITS)
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template <>
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bool IsAligned<8>(const void* pointer) {
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return reinterpret_cast<uintptr_t>(pointer) % 4 == 0;
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}
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#endif
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template <size_t size, size_t alignment>
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void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer(const void* pointer) {
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CHECK(pointer && IsAligned<alignment>(pointer));
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}
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// Explicitly instantiate the sizes we need. Add instantiations as needed.
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template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<1, 1>(const void*);
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template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<4, 4>(const void*);
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template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<8, 4>(const void*);
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template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<8, 8>(const void*);
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template <size_t size, size_t alignment>
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void MOJO_SYSTEM_IMPL_EXPORT
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CheckUserPointerWithCount(const void* pointer, size_t count) {
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CHECK_LE(count, std::numeric_limits<size_t>::max() / size);
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CHECK(count == 0 || (pointer && IsAligned<alignment>(pointer)));
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}
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// Explicitly instantiate the sizes we need. Add instantiations as needed.
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template void MOJO_SYSTEM_IMPL_EXPORT
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CheckUserPointerWithCount<1, 1>(const void*, size_t);
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template void MOJO_SYSTEM_IMPL_EXPORT
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CheckUserPointerWithCount<4, 4>(const void*, size_t);
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template void MOJO_SYSTEM_IMPL_EXPORT
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CheckUserPointerWithCount<8, 4>(const void*, size_t);
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template void MOJO_SYSTEM_IMPL_EXPORT
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CheckUserPointerWithCount<8, 8>(const void*, size_t);
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template <size_t alignment>
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void CheckUserPointerWithSize(const void* pointer, size_t size) {
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// TODO(vtl): If running in kernel mode, do a full verification. For now, just
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// check that it's non-null and aligned. (A faster user mode implementation is
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// also possible if this check is skipped.)
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CHECK(size == 0 || (!!pointer && internal::IsAligned<alignment>(pointer)));
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}
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// Explicitly instantiate the sizes we need. Add instantiations as needed.
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template void MOJO_SYSTEM_IMPL_EXPORT
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CheckUserPointerWithSize<1>(const void*, size_t);
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template void MOJO_SYSTEM_IMPL_EXPORT
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CheckUserPointerWithSize<4>(const void*, size_t);
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// Whereas the other |Check...()| functions are usually used with integral typs
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// or arrays of integral types, this one is used with Options structs for which
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// alignment has been explicitly been specified (using |MOJO_ALIGNAS()|), which
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// MSVS *does* respect.
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#if defined(COMPILER_MSVC) && defined(ARCH_CPU_32_BITS)
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template <>
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void MOJO_SYSTEM_IMPL_EXPORT
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CheckUserPointerWithSize<8>(const void* pointer, size_t size) {
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CHECK(size == 0 ||
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(!!pointer && reinterpret_cast<uintptr_t>(pointer) % 8 == 0));
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}
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#else
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template void MOJO_SYSTEM_IMPL_EXPORT
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CheckUserPointerWithSize<8>(const void*, size_t);
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#endif
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} // namespace internal
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} // namespace system
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} // namespace mojo
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