100 lines
1.4 KiB
C
100 lines
1.4 KiB
C
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/*++
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Copyright (c) 2000 Microsoft Corporation
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Module Name:
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vfrandom.c
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Abstract:
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This module implements support for random number generation needed by the
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verifier.
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Author:
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Adrian J. Oney (adriao) 28-Jun-2000
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Environment:
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Kernel mode
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Revision History:
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--*/
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#include "vfdef.h"
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(INIT, VfRandomInit)
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#pragma alloc_text(PAGEVRFY, VfRandomGetNumber)
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#endif // ALLOC_PRAGMA
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VOID
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VfRandomInit(
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VOID
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)
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/*++
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Routine Description:
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This routine initializes the random number generator, seeing it based on
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the startup time of the machine.
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Arguments:
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None.
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Return Value:
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None.
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--*/
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{
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}
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ULONG
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FASTCALL
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VfRandomGetNumber(
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IN ULONG Minimum,
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IN ULONG Maximum
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)
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/*++
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Routine Description:
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This routine returns a random number in the range [Minimum, Maximum].
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Arguments:
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Minimum - Minimum value returnable
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Maximum - Maximum value returnable
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Return Value:
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A random number between Minimum and Maximum
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--*/
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{
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LARGE_INTEGER performanceCounter;
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//
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// This should be replaced with the algorithm from rtl\random.c
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//
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KeQueryPerformanceCounter(&performanceCounter);
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if (Maximum + 1 == Minimum) {
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return performanceCounter.LowPart;
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} else {
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return (performanceCounter.LowPart % (Maximum - Minimum + 1)) + Minimum;
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}
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}
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