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 #if defined (ALLOC_PRAGMA)
  17 #pragma alloc_text(INIT, SepInitLuid)
  18 #endif
  19
  20
  21 /* GLOBALS *******************************************************************/
  22
  23 static LARGE_INTEGER LuidIncrement;
  24 static LARGE_INTEGER LuidValue;
  25
  26 /* FUNCTIONS *****************************************************************/
  27
  28 VOID
  29 INIT_FUNCTION
  30 NTAPI
  31 SepInitLuid(VOID)
  32 {
  33   LUID DummyLuidValue = SYSTEM_LUID;
  34
  35   LuidValue.u.HighPart = DummyLuidValue.HighPart;
  36   LuidValue.u.LowPart = DummyLuidValue.LowPart;
  37   LuidIncrement.QuadPart = 1;
  38 }
  39
  40
  41 NTSTATUS
  42 NTAPI
  43 ExpAllocateLocallyUniqueId(OUT LUID *LocallyUniqueId)
  44 {
  45   LARGE_INTEGER NewLuid, PrevLuid;
  46
  47   /* atomically increment the luid */
  48   do
  49   {
  50     PrevLuid = LuidValue;
  51     NewLuid = RtlLargeIntegerAdd(PrevLuid,
  52                                  LuidIncrement);
  53   } while(ExfInterlockedCompareExchange64(&LuidValue.QuadPart,
  54                                           &NewLuid.QuadPart,
  55                                           &PrevLuid.QuadPart) != PrevLuid.QuadPart);
  56
  57   LocallyUniqueId->LowPart = NewLuid.u.LowPart;
  58   LocallyUniqueId->HighPart = NewLuid.u.HighPart;
  59
  60   return STATUS_SUCCESS;
  61 }
  62
  63
  64 /*
  65  * @implemented
  66  */
  67 NTSTATUS STDCALL
  68 NtAllocateLocallyUniqueId(OUT LUID *LocallyUniqueId)
  69 {
  70   LUID NewLuid;
  71   KPROCESSOR_MODE PreviousMode;
  72   NTSTATUS Status = STATUS_SUCCESS;
  73
  74   PAGED_CODE();
  75
  76   PreviousMode = ExGetPreviousMode();
  77
  78   if(PreviousMode != KernelMode)
  79   {
  80     _SEH_TRY
  81     {
  82       ProbeForWrite(LocallyUniqueId,
  83                     sizeof(LUID),
  84                     sizeof(ULONG));
  85     }
  86     _SEH_HANDLE
  87     {
  88       Status = _SEH_GetExceptionCode();
  89     }
  90     _SEH_END;
  91
  92     if(!NT_SUCCESS(Status))
  93     {
  94       return Status;
  95     }
  96   }
  97
  98   Status = ExpAllocateLocallyUniqueId(&NewLuid);
  99
 100   _SEH_TRY
 101   {
 102     *LocallyUniqueId = NewLuid;
 103   }
 104   _SEH_HANDLE
 105   {
 106     Status = _SEH_GetExceptionCode();
 107   }
 108   _SEH_END;
 109
 110   return Status;
 111 }
 112
 113 /* EOF */