348 lines
7.9 KiB
C
348 lines
7.9 KiB
C
/*++
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Copyright (c) 1989 Microsoft Corporation
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Module Name:
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mutntobj.c
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Abstract:
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This module implements the kernel mutant object. Functions are
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provided to initialize, read, and release mutant objects.
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N.B. Kernel mutex objects have been subsumed by mutant objects.
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Author:
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David N. Cutler (davec) 16-Oct-1989
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Environment:
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Kernel mode only.
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Revision History:
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--*/
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#include "ki.h"
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//
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// The following assert macro is used to check that an input mutant is
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// really a kmutant and not something else, like deallocated pool.
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//
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#define ASSERT_MUTANT(E) { \
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ASSERT((E)->Header.Type == MutantObject); \
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}
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VOID
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KeInitializeMutant (
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IN PRKMUTANT Mutant,
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IN BOOLEAN InitialOwner
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)
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/*++
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Routine Description:
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This function initializes a kernel mutant object.
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Arguments:
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Mutant - Supplies a pointer to a dispatcher object of type mutant.
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InitialOwner - Supplies a boolean value that determines whether the
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current thread is to be the initial owner of the mutant object.
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Return Value:
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None.
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--*/
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{
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PLIST_ENTRY ListEntry;
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KIRQL OldIrql;
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PRKTHREAD Thread;
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//
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// Initialize standard dispatcher object header, set the owner thread to
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// NULL, set the abandoned state to FALSE, and set the APC disable count
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// to zero (this is the only thing that distinguishes a mutex from a mutant).
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//
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Mutant->Header.Type = MutantObject;
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Mutant->Header.Size = sizeof(KMUTANT) / sizeof(LONG);
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if (InitialOwner == TRUE) {
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Thread = KeGetCurrentThread();
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Mutant->Header.SignalState = 0;
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Mutant->OwnerThread = Thread;
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KiLockDispatcherDatabase(&OldIrql);
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ListEntry = Thread->MutantListHead.Blink;
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InsertHeadList(ListEntry, &Mutant->MutantListEntry);
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KiUnlockDispatcherDatabase(OldIrql);
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} else {
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Mutant->Header.SignalState = 1;
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Mutant->OwnerThread = (PKTHREAD)NULL;
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}
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InitializeListHead(&Mutant->Header.WaitListHead);
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Mutant->Abandoned = FALSE;
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Mutant->ApcDisable = 0;
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return;
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}
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VOID
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KeInitializeMutex (
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IN PRKMUTANT Mutant,
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IN ULONG Level
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)
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/*++
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Routine Description:
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This function initializes a kernel mutex object. The level number
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is ignored.
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N.B. Kernel mutex objects have been subsumed by mutant objects.
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Arguments:
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Mutex - Supplies a pointer to a dispatcher object of type mutex.
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Level - Ignored.
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Return Value:
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None.
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--*/
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{
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PLIST_ENTRY ListEntry;
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//
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// Initialize standard dispatcher object header, set the owner thread to
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// NULL, set the abandoned state to FALSE, adn set the APC disable count
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// to one (this is the only thing that distinguishes a mutex from a mutant).
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//
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Mutant->Header.Type = MutantObject;
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Mutant->Header.Size = sizeof(KMUTANT) / sizeof(LONG);
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Mutant->Header.SignalState = 1;
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InitializeListHead(&Mutant->Header.WaitListHead);
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Mutant->OwnerThread = (PKTHREAD)NULL;
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Mutant->Abandoned = FALSE;
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Mutant->ApcDisable = 1;
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return;
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}
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LONG
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KeReadStateMutant (
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IN PRKMUTANT Mutant
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)
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/*++
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Routine Description:
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This function reads the current signal state of a mutant object.
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Arguments:
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Mutant - Supplies a pointer to a dispatcher object of type mutant.
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Return Value:
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The current signal state of the mutant object.
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--*/
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{
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ASSERT_MUTANT(Mutant);
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//
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// Return current signal state of mutant object.
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//
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return Mutant->Header.SignalState;
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}
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LONG
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KeReleaseMutant (
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IN PRKMUTANT Mutant,
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IN KPRIORITY Increment,
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IN BOOLEAN Abandoned,
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IN BOOLEAN Wait
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)
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/*++
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Routine Description:
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This function releases a mutant object by incrementing the mutant
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count. If the resultant value is one, then an attempt is made to
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satisfy as many Waits as possible. The previous signal state of
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the mutant is returned as the function value. If the Abandoned
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parameter is TRUE, then the mutant object is released by settings
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the signal state to one.
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Arguments:
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Mutant - Supplies a pointer to a dispatcher object of type mutant.
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Increment - Supplies the priority increment that is to be applied
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if setting the event causes a Wait to be satisfied.
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Abandoned - Supplies a boolean value that signifies whether the
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mutant object is being abandoned.
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Wait - Supplies a boolean value that signifies whether the call to
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KeReleaseMutant will be immediately followed by a call to one
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of the kernel Wait functions.
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Return Value:
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The previous signal state of the mutant object.
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--*/
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{
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KIRQL OldIrql;
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LONG OldState;
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PRKTHREAD Thread;
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ASSERT_MUTANT(Mutant);
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ASSERT(KeGetCurrentIrql() <= DISPATCH_LEVEL);
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//
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// Raise IRQL to dispatcher level and lock dispatcher database.
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//
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KiLockDispatcherDatabase(&OldIrql);
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//
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// Capture the current signal state of the mutant object.
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//
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OldState = Mutant->Header.SignalState;
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//
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// If the Abandoned parameter is TRUE, then force the release of the
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// mutant object by setting its ownership count to one and setting its
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// abandoned state to TRUE. Otherwise increment mutant ownership count.
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// If the result count is one, then remove the mutant object from the
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// thread's owned mutant list, set the owner thread to NULL, and attempt
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// to satisfy a Wait for the mutant object if the mutant object wait
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// list is not empty.
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//
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Thread = KeGetCurrentThread();
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if (Abandoned != FALSE) {
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Mutant->Header.SignalState = 1;
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Mutant->Abandoned = TRUE;
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} else {
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//
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// If the Mutant object is not owned by the current thread, then
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// unlock the dispatcher data base and raise an exception. Otherwise
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// increment the ownership count.
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//
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if (Mutant->OwnerThread != Thread) {
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KiUnlockDispatcherDatabase(OldIrql);
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ExRaiseStatus(Mutant->Abandoned ?
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STATUS_ABANDONED : STATUS_MUTANT_NOT_OWNED);
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}
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Mutant->Header.SignalState += 1;
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}
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if (Mutant->Header.SignalState == 1) {
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if (OldState <= 0) {
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RemoveEntryList(&Mutant->MutantListEntry);
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Thread->KernelApcDisable += Mutant->ApcDisable;
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if ((Thread->KernelApcDisable == 0) &&
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(IsListEmpty(&Thread->ApcState.ApcListHead[KernelMode]) == FALSE)) {
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Thread->ApcState.KernelApcPending = TRUE;
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KiRequestSoftwareInterrupt(APC_LEVEL);
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}
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}
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Mutant->OwnerThread = (PKTHREAD)NULL;
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if (IsListEmpty(&Mutant->Header.WaitListHead) == FALSE) {
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KiWaitTest(Mutant, Increment);
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}
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}
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//
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// If the value of the Wait argument is TRUE, then return to
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// caller with IRQL raised and the dispatcher database locked.
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// Else release the dispatcher database lock and lower IRQL to
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// its previous value.
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//
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if (Wait != FALSE) {
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Thread->WaitNext = Wait;
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Thread->WaitIrql = OldIrql;
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} else {
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KiUnlockDispatcherDatabase(OldIrql);
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}
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//
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// Return previous signal state of mutant object.
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//
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return OldState;
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}
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LONG
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KeReleaseMutex (
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IN PRKMUTANT Mutex,
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IN BOOLEAN Wait
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)
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/*++
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Routine Description:
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This function releases a mutex object.
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N.B. Kernel mutex objects have been subsumed by mutant objects.
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Arguments:
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Mutex - Supplies a pointer to a dispatcher object of type mutex.
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Wait - Supplies a boolean value that signifies whether the call to
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KeReleaseMutex will be immediately followed by a call to one
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of the kernel Wait functions.
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Return Value:
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The previous signal state of the mutex object.
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--*/
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{
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ASSERT_MUTANT(Mutex);
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//
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// Release the specified mutex object with defaults for increment
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// and abandoned parameters.
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//
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return KeReleaseMutant(Mutex, 1, FALSE, Wait);
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}
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