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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_WIN_WINDOWS_HANDLE_UTIL_H_
#define BASE_WIN_WINDOWS_HANDLE_UTIL_H_
#include <stdint.h>
#include "base/win/windows_types.h"
namespace base::win {
inline bool IsPseudoHandle(HANDLE h) {
// Note that there appears to be no official documentation covering the
// existence of specific pseudo handle values. In practice it's clear that
// e.g. -1 is the current process, -2 is the current thread, etc. The largest
// negative value known to be an issue with DuplicateHandle in fuzzers is
// -12.
//
// Note that there is virtually no risk of a real handle value falling within
// this range and being misclassified as a pseudo handle.
//
// Cast through uintptr_t and then unsigned int to make the truncation to
// 32 bits explicit. Handles are size of-pointer but are always 32-bit values.
// https://msdn.microsoft.com/en-us/library/aa384203(VS.85).aspx says:
// 64-bit versions of Windows use 32-bit handles for interoperability.
static constexpr int kMinimumKnownPseudoHandleValue = -12;
const auto value = static_cast<int32_t>(reinterpret_cast<uintptr_t>(h));
return value < 0 && value >= kMinimumKnownPseudoHandleValue;
}
inline uint32_t HandleToUint32(HANDLE h) {
// Cast through uintptr_t and then unsigned int to make the truncation to
// 32 bits explicit. Handles are size of-pointer but are always 32-bit values.
// https://msdn.microsoft.com/en-us/library/aa384203(VS.85).aspx says:
// 64-bit versions of Windows use 32-bit handles for interoperability.
return static_cast<uint32_t>(reinterpret_cast<uintptr_t>(h));
}
inline HANDLE Uint32ToHandle(uint32_t h) {
return reinterpret_cast<HANDLE>(
static_cast<uintptr_t>(static_cast<int32_t>(h)));
}
} // namespace base::win
#endif // BASE_WIN_WINDOWS_HANDLE_UTIL_H_
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