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 INIT_FUNCTION
  24 SepInitLuid(VOID)
  25 {
  26   LUID DummyLuidValue = SYSTEM_LUID;
  27
  28   LuidValue.u.HighPart = DummyLuidValue.HighPart;
  29   LuidValue.u.LowPart = DummyLuidValue.LowPart;
  30   LuidIncrement.QuadPart = 1;
  31 }
  32
  33
  34 NTSTATUS
  35 ExpAllocateLocallyUniqueId(OUT LUID *LocallyUniqueId)
  36 {
  37   LARGE_INTEGER NewLuid, PrevLuid;
  38
  39   /* atomically increment the luid */
  40   do
  41   {
  42     PrevLuid = (volatile LARGE_INTEGER)LuidValue;
  43     NewLuid = RtlLargeIntegerAdd(PrevLuid,
  44                                  LuidIncrement);
  45   } while(ExfInterlockedCompareExchange64(&LuidValue.QuadPart,
  46                                           &NewLuid.QuadPart,
  47                                           &PrevLuid.QuadPart) != PrevLuid.QuadPart);
  48
  49   LocallyUniqueId->LowPart = NewLuid.u.LowPart;
  50   LocallyUniqueId->HighPart = NewLuid.u.HighPart;
  51
  52   return STATUS_SUCCESS;
  53 }
  54
  55
  56 /*
  57  * @implemented
  58  */
  59 NTSTATUS STDCALL
  60 NtAllocateLocallyUniqueId(OUT LUID *LocallyUniqueId)
  61 {
  62   LUID NewLuid;
  63   KPROCESSOR_MODE PreviousMode;
  64   NTSTATUS Status = STATUS_SUCCESS;
  65
  66   PAGED_CODE();
  67
  68   PreviousMode = ExGetPreviousMode();
  69
  70   if(PreviousMode != KernelMode)
  71   {
  72     _SEH_TRY
  73     {
  74       ProbeForWrite(LocallyUniqueId,
  75                     sizeof(LUID),
  76                     sizeof(ULONG));
  77     }
  78     _SEH_HANDLE
  79     {
  80       Status = _SEH_GetExceptionCode();
  81     }
  82     _SEH_END;
  83
  84     if(!NT_SUCCESS(Status))
  85     {
  86       return Status;
  87     }
  88   }
  89
  90   Status = ExpAllocateLocallyUniqueId(&NewLuid);
  91
  92   _SEH_TRY
  93   {
  94     *LocallyUniqueId = NewLuid;
  95   }
  96   _SEH_HANDLE
  97   {
  98     Status = _SEH_GetExceptionCode();
  99   }
 100   _SEH_END;
 101
 102   return Status;
 103 }
 104
 105 /* EOF */