reactos/ntoskrnl/ke/sem.c

   1 /*
   2  * COPYRIGHT:       See COPYING in the top level directory
   3  * PROJECT:         ReactOS kernel
   4  * FILE:            ntoskrnl/ke/sem.c
   5  * PURPOSE:         Implements kernel semaphores
   6  * PROGRAMMER:      David Welch (welch@mcmail.com)
   7  * UPDATE HISTORY:
   8  *                  Created 22/05/98
   9  */
  10
  11 /* INCLUDES *****************************************************************/
  12
  13 #include <ddk/ntddk.h>
  14 #include <internal/ke.h>
  15
  16 #include <internal/debug.h>
  17
  18 /* FUNCTIONS *****************************************************************/
  19
  20 VOID KeInitializeSemaphore(PKSEMAPHORE Semaphore,
  21                            LONG Count,
  22                            LONG Limit)
  23 {
  24    KeInitializeDispatcherHeader(&Semaphore->Header,SemaphoreType,
  25                                 sizeof(KSEMAPHORE)/sizeof(ULONG),
  26                                 Count);
  27    Semaphore->Limit=Limit;
  28 }
  29
  30 LONG KeReadStateSemaphore(PKSEMAPHORE Semaphore)
  31 {
  32    return(Semaphore->Header.SignalState);
  33 }
  34
  35 LONG KeReleaseSemaphore(PKSEMAPHORE Semaphore,
  36                         KPRIORITY Increment,
  37                         LONG Adjustment,
  38                         BOOLEAN Wait)
  39 {
  40  ULONG initState = Semaphore->Header.SignalState;
  41   KeAcquireDispatcherDatabaseLock(Wait);
  42   if(Semaphore->Limit < initState+Adjustment
  43       || initState > initState+Adjustment)
  44      ExRaiseStatus(STATUS_SEMAPHORE_LIMIT_EXCEEDED);
  45   Semaphore->Header.SignalState+=Adjustment;
  46   if(initState == 0)
  47   {
  48     //  wake up SignalState waiters
  49     KeDispatcherObjectWake(&Semaphore->Header)  ;
  50   }
  51   KeReleaseDispatcherDatabaseLock(Wait);
  52   return initState;
  53 }
  54