mirror of
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108 lines
2.6 KiB
C
108 lines
2.6 KiB
C
/*
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* PROJECT: ReactOS Kernel
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* LICENSE: GPL - See COPYING in the top level directory
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* FILE: ntoskrnl/ke/sem.c
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* PURPOSE: Implements the Semaphore Dispatcher Object
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* PROGRAMMERS: Alex Ionescu (alex.ionescu@reactos.org)
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*/
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/* INCLUDES ******************************************************************/
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#include <ntoskrnl.h>
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#define NDEBUG
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#include <debug.h>
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/* FUNCTIONS *****************************************************************/
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/*
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* @implemented
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*/
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VOID
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NTAPI
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KeInitializeSemaphore(IN PKSEMAPHORE Semaphore,
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IN LONG Count,
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IN LONG Limit)
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{
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/* Simply Initialize the Header */
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KeInitializeDispatcherHeader(&Semaphore->Header,
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SemaphoreObject,
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sizeof(KSEMAPHORE) / sizeof(ULONG),
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Count);
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/* Set the Limit */
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Semaphore->Limit = Limit;
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}
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/*
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* @implemented
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*/
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LONG
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NTAPI
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KeReadStateSemaphore(IN PKSEMAPHORE Semaphore)
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{
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ASSERT_SEMAPHORE(Semaphore);
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/* Just return the Signal State */
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return Semaphore->Header.SignalState;
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}
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/*
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* @implemented
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*/
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LONG
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NTAPI
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KeReleaseSemaphore(IN PKSEMAPHORE Semaphore,
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IN KPRIORITY Increment,
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IN LONG Adjustment,
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IN BOOLEAN Wait)
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{
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LONG InitialState, State;
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KIRQL OldIrql;
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PKTHREAD CurrentThread;
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ASSERT_SEMAPHORE(Semaphore);
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ASSERT_IRQL_LESS_OR_EQUAL(DISPATCH_LEVEL);
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/* Lock the Dispatcher Database */
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OldIrql = KiAcquireDispatcherLock();
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/* Save the Old State and get new one */
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InitialState = Semaphore->Header.SignalState;
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State = InitialState + Adjustment;
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/* Check if the Limit was exceeded */
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if ((Semaphore->Limit < State) || (InitialState > State))
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{
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/* Raise an error if it was exceeded */
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KiReleaseDispatcherLock(OldIrql);
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ExRaiseStatus(STATUS_SEMAPHORE_LIMIT_EXCEEDED);
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}
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/* Now set the new state */
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Semaphore->Header.SignalState = State;
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/* Check if we should wake it */
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if (!(InitialState) && !(IsListEmpty(&Semaphore->Header.WaitListHead)))
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{
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/* Wake the Semaphore */
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KiWaitTest(&Semaphore->Header, Increment);
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}
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/* Check if the caller wants to wait after this release */
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if (Wait == FALSE)
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{
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/* Release the Lock */
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KiReleaseDispatcherLock(OldIrql);
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}
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else
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{
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/* Set a wait */
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CurrentThread = KeGetCurrentThread();
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CurrentThread->WaitNext = TRUE;
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CurrentThread->WaitIrql = OldIrql;
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}
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/* Return the previous state */
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return InitialState;
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}
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/* EOF */
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