reactos/ntoskrnl/se/luid.c

   1 /* $Id$
   2  *
   3  * COPYRIGHT:       See COPYING in the top level directory
   4  * PROJECT:         ReactOS kernel
   5  * FILE:            ntoskrnl/se/luid.c
   6  * PURPOSE:         Security manager
   7  *
   8  * PROGRAMMERS:     No programmer listed.
   9  */
  10
  11 /* INCLUDES *****************************************************************/
  12
  13 #include <ntoskrnl.h>
  14 #include <internal/debug.h>
  15
  16 /* GLOBALS *******************************************************************/
  17
  18 static LARGE_INTEGER LuidIncrement;
  19 static LARGE_INTEGER LuidValue;
  20
  21 /* FUNCTIONS *****************************************************************/
  22
  23 VOID
  24 INIT_FUNCTION
  25 NTAPI
  26 SepInitLuid(VOID)
  27 {
  28   LUID DummyLuidValue = SYSTEM_LUID;
  29
  30   LuidValue.u.HighPart = DummyLuidValue.HighPart;
  31   LuidValue.u.LowPart = DummyLuidValue.LowPart;
  32   LuidIncrement.QuadPart = 1;
  33 }
  34
  35
  36 NTSTATUS
  37 NTAPI
  38 ExpAllocateLocallyUniqueId(OUT LUID *LocallyUniqueId)
  39 {
  40   LARGE_INTEGER NewLuid, PrevLuid;
  41
  42   /* atomically increment the luid */
  43   do
  44   {
  45     PrevLuid = LuidValue;
  46     NewLuid = RtlLargeIntegerAdd(PrevLuid,
  47                                  LuidIncrement);
  48   } while(ExfInterlockedCompareExchange64(&LuidValue.QuadPart,
  49                                           &NewLuid.QuadPart,
  50                                           &PrevLuid.QuadPart) != PrevLuid.QuadPart);
  51
  52   LocallyUniqueId->LowPart = NewLuid.u.LowPart;
  53   LocallyUniqueId->HighPart = NewLuid.u.HighPart;
  54
  55   return STATUS_SUCCESS;
  56 }
  57
  58
  59 /*
  60  * @implemented
  61  */
  62 NTSTATUS STDCALL
  63 NtAllocateLocallyUniqueId(OUT LUID *LocallyUniqueId)
  64 {
  65   LUID NewLuid;
  66   KPROCESSOR_MODE PreviousMode;
  67   NTSTATUS Status = STATUS_SUCCESS;
  68
  69   PAGED_CODE();
  70
  71   PreviousMode = ExGetPreviousMode();
  72
  73   if(PreviousMode != KernelMode)
  74   {
  75     _SEH_TRY
  76     {
  77       ProbeForWrite(LocallyUniqueId,
  78                     sizeof(LUID),
  79                     sizeof(ULONG));
  80     }
  81     _SEH_HANDLE
  82     {
  83       Status = _SEH_GetExceptionCode();
  84     }
  85     _SEH_END;
  86
  87     if(!NT_SUCCESS(Status))
  88     {
  89       return Status;
  90     }
  91   }
  92
  93   Status = ExpAllocateLocallyUniqueId(&NewLuid);
  94
  95   _SEH_TRY
  96   {
  97     *LocallyUniqueId = NewLuid;
  98   }
  99   _SEH_HANDLE
 100   {
 101     Status = _SEH_GetExceptionCode();
 102   }
 103   _SEH_END;
 104
 105   return Status;
 106 }
 107
 108 /* EOF */