1220 lines
36 KiB
C
1220 lines
36 KiB
C
/*++
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Copyright (c) 1989 Microsoft Corporation
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Module Name:
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wait.c
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Abstract:
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This module implements the generic kernel wait routines. Functions
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are provided to wait for a single object, wait for multiple objects,
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wait for event pair low, wait for event pair high, release and wait
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for semaphore, and to delay thread execution.
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N.B. This module is written to be a fast as possible and not as small
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as possible. Therefore some code sequences are duplicated to avoid
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procedure calls. It would also be possible to combine wait for
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single object into wait for multiple objects at the cost of some
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speed. Since wait for single object is the most common case, the
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two routines have been separated.
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Author:
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David N. Cutler (davec) 23-Mar-89
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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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// Test for alertable condition.
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// If alertable is TRUE and the thread is alerted for a processor
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// mode that is equal to the wait mode, then return immediately
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// with a wait completion status of ALERTED.
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// Else if alertable is TRUE, the wait mode is user, and the user APC
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// queue is not empty, then set user APC pending, and return immediately
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// with a wait completion status of USER_APC.
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// Else if alertable is TRUE and the thread is alerted for kernel
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// mode, then return immediately with a wait completion status of
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// ALERTED.
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// Else if alertable is FALSE and the wait mode is user and there is a
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// user APC pending, then return immediately with a wait completion
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// status of USER_APC.
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#define TestForAlertPending(Alertable) \
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if (Alertable) { \
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if (Thread->Alerted[WaitMode] != FALSE) { \
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Thread->Alerted[WaitMode] = FALSE; \
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WaitStatus = STATUS_ALERTED; \
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break; \
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} else if ((WaitMode != KernelMode) && \
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(IsListEmpty(&Thread->ApcState.ApcListHead[UserMode])) == FALSE) { \
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Thread->ApcState.UserApcPending = TRUE; \
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WaitStatus = STATUS_USER_APC; \
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break; \
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} else if (Thread->Alerted[KernelMode] != FALSE) { \
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Thread->Alerted[KernelMode] = FALSE; \
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WaitStatus = STATUS_ALERTED; \
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break; \
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} \
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} else if ((WaitMode != KernelMode) && (Thread->ApcState.UserApcPending)) { \
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WaitStatus = STATUS_USER_APC; \
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break; \
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}
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VOID
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KiAdjustQuantumThread (
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IN PKTHREAD Thread
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)
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/*++
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Routine Description:
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If the current thread is not a time critical or realtime thread, then
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adjust its quantum in accordance with the adjustment that would have
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occured if the thread had actually waited.
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Arguments:
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Thread - Supplies a pointer to the current thread.
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Return Value:
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None.
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--*/
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{
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PKPRCB Prcb;
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PKPROCESS Process;
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PKTHREAD NewThread;
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SCHAR ThreadPriority;
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if ((Thread->Priority < LOW_REALTIME_PRIORITY) &&
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(Thread->BasePriority < TIME_CRITICAL_PRIORITY_BOUND)) {
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Thread->Quantum -= WAIT_QUANTUM_DECREMENT;
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if (Thread->Quantum <= 0) {
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Process = Thread->ApcState.Process;
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Thread->Quantum = Process->ThreadQuantum;
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ThreadPriority = Thread->Priority - (Thread->PriorityDecrement + 1);
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if (ThreadPriority < Thread->BasePriority) {
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ThreadPriority = Thread->BasePriority;
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}
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Thread->PriorityDecrement = 0;
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if (ThreadPriority != Thread->Priority) {
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KiSetPriorityThread(Thread, ThreadPriority);
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} else {
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Prcb = KeGetCurrentPrcb();
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if (Prcb->NextThread == NULL) {
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NewThread = KiFindReadyThread(Thread->NextProcessor,
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ThreadPriority);
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if (NewThread != NULL) {
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Prcb->NextThread = NewThread;
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NewThread->State = Standby;
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}
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}
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}
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}
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}
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return;
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}
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NTSTATUS
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KeDelayExecutionThread (
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IN KPROCESSOR_MODE WaitMode,
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IN BOOLEAN Alertable,
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IN PLARGE_INTEGER Interval
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)
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/*++
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Routine Description:
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This function delays the execution of the current thread for the specified
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interval of time.
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Arguments:
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WaitMode - Supplies the processor mode in which the delay is to occur.
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Alertable - Supplies a boolean value that specifies whether the delay
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is alertable.
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Interval - Supplies a pointer to the absolute or relative time over which
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the delay is to occur.
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Return Value:
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The wait completion status. A value of STATUS_SUCCESS is returned if
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the delay occurred. A value of STATUS_ALERTED is returned if the wait
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was aborted to deliver an alert to the current thread. A value of
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STATUS_USER_APC is returned if the wait was aborted to deliver a user
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APC to the current thread.
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--*/
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{
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LARGE_INTEGER DueTime;
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LARGE_INTEGER NewTime;
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PLARGE_INTEGER OriginalTime;
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PKPRCB Prcb;
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KPRIORITY Priority;
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PRKQUEUE Queue;
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PRKTHREAD Thread;
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PRKTIMER Timer;
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PKWAIT_BLOCK WaitBlock;
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NTSTATUS WaitStatus;
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// If the dispatcher database lock is not already held, then set the wait
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// IRQL and lock the dispatcher database. Else set boolean wait variable
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// to FALSE.
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Thread = KeGetCurrentThread();
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if (Thread->WaitNext) {
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Thread->WaitNext = FALSE;
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} else {
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KiLockDispatcherDatabase(&Thread->WaitIrql);
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}
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// Start of delay loop.
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// Note this loop is repeated if a kernel APC is delivered in the middle
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// of the delay or a kernel APC is pending on the first attempt through
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// the loop.
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OriginalTime = Interval;
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WaitBlock = &Thread->WaitBlock[TIMER_WAIT_BLOCK];
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do {
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// Test to determine if a kernel APC is pending.
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// If a kernel APC is pending and the previous IRQL was less than
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// APC_LEVEL, then a kernel APC was queued by another processor just
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// after IRQL was raised to DISPATCH_LEVEL, but before the dispatcher
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// database was locked.
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// N.B. that this can only happen in a multiprocessor system.
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if (Thread->ApcState.KernelApcPending && (Thread->WaitIrql < APC_LEVEL)) {
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// Unlock the dispatcher database and lower IRQL to its previous
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// value. An APC interrupt will immediately occur which will result
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// in the delivery of the kernel APC if possible.
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KiUnlockDispatcherDatabase(Thread->WaitIrql);
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} else {
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// Test for alert pending.
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TestForAlertPending(Alertable);
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// Initialize wait block, insert wait block in timer wait list,
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// insert timer in timer queue, put thread in wait state, select
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// next thread to execute, and context switch to next thread.
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// N.B. The timer wait block is initialized when the respective
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// thread is initialized. Thus the constant fields are not
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// reinitialized. These include the wait object, wait key,
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// wait type, and the wait list entry link pointers.
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Thread->WaitBlockList = WaitBlock;
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Thread->WaitStatus = (NTSTATUS)0;
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Timer = &Thread->Timer;
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WaitBlock->NextWaitBlock = WaitBlock;
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Timer->Header.WaitListHead.Flink = &WaitBlock->WaitListEntry;
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Timer->Header.WaitListHead.Blink = &WaitBlock->WaitListEntry;
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// If the timer is inserted in the timer tree, then place the
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// current thread in a wait state. Otherwise, attempt to force
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// the current thread to yield the processor to another thread.
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if (KiInsertTreeTimer(Timer, *Interval) == FALSE) {
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// If the thread is not a realtime thread, then drop the
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// thread priority to the base priority.
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Prcb = KeGetCurrentPrcb();
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Priority = Thread->Priority;
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if (Priority < LOW_REALTIME_PRIORITY) {
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if (Priority != Thread->BasePriority) {
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Thread->PriorityDecrement = 0;
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KiSetPriorityThread(Thread, Thread->BasePriority);
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}
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}
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// If a new thread has not been selected, the attempt to round
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// robin the thread with other threads at the same priority.
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if (Prcb->NextThread == NULL) {
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Prcb->NextThread = KiFindReadyThread(Thread->NextProcessor,
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Thread->Priority);
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}
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// If a new thread has been selected for execution, then
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// switch immediately to the selected thread.
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if (Prcb->NextThread != NULL) {
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// Give the current thread a new qunatum and switch
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// context to selected thread.
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// N.B. Control is returned at the original IRQL.
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Thread->Preempted = FALSE;
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Thread->Quantum = Thread->ApcState.Process->ThreadQuantum;
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ASSERT(Thread->WaitIrql <= DISPATCH_LEVEL);
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KiReadyThread(Thread);
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WaitStatus = (NTSTATUS)KiSwapThread();
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goto WaitComplete;
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} else {
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WaitStatus = (NTSTATUS)STATUS_SUCCESS;
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break;
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}
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}
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DueTime.QuadPart = Timer->DueTime.QuadPart;
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// If the current thread is processing a queue entry, then attempt
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// to activate another thread that is blocked on the queue object.
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Queue = Thread->Queue;
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if (Queue != NULL) {
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KiActivateWaiterQueue(Queue);
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}
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// Set the thread wait parameters, set the thread dispatcher state
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// to Waiting, and insert the thread in the wait list.
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Thread->Alertable = Alertable;
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Thread->WaitMode = WaitMode;
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Thread->WaitReason = DelayExecution;
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Thread->WaitTime= KiQueryLowTickCount();
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Thread->State = Waiting;
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KiInsertWaitList(WaitMode, Thread);
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// Switch context to selected thread.
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// N.B. Control is returned at the original IRQL.
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ASSERT(Thread->WaitIrql <= DISPATCH_LEVEL);
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WaitStatus = (NTSTATUS)KiSwapThread();
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// If the thread was not awakened to deliver a kernel mode APC,
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// then return the wait status.
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WaitComplete:
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if (WaitStatus != STATUS_KERNEL_APC) {
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if (WaitStatus == STATUS_TIMEOUT) {
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WaitStatus = STATUS_SUCCESS;
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}
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return WaitStatus;
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}
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// Reduce the time remaining before the time delay expires.
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Interval = KiComputeWaitInterval(OriginalTime,
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&DueTime,
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&NewTime);
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}
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// Raise IRQL to DISPATCH_LEVEL and lock the dispatcher database.
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KiLockDispatcherDatabase(&Thread->WaitIrql);
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} while (TRUE);
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// The thread is alerted or a user APC should be delivered. Unlock the
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// dispatcher database, lower IRQL to its previous value, and return the
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// wait status.
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|
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KiUnlockDispatcherDatabase(Thread->WaitIrql);
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return WaitStatus;
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}
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NTSTATUS
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KeWaitForMultipleObjects (
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IN ULONG Count,
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IN PVOID Object[],
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IN WAIT_TYPE WaitType,
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IN KWAIT_REASON WaitReason,
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IN KPROCESSOR_MODE WaitMode,
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IN BOOLEAN Alertable,
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IN PLARGE_INTEGER Timeout OPTIONAL,
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IN PKWAIT_BLOCK WaitBlockArray OPTIONAL
|
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)
|
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/*++
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Routine Description:
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This function waits until the specified objects attain a state of
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Signaled. The wait can be specified to wait until all of the objects
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attain a state of Signaled or until one of the objects attains a state
|
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of Signaled. An optional timeout can also be specified. If a timeout
|
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is not specified, then the wait will not be satisfied until the objects
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attain a state of Signaled. If a timeout is specified, and the objects
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have not attained a state of Signaled when the timeout expires, then
|
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the wait is automatically satisfied. If an explicit timeout value of
|
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zero is specified, then no wait will occur if the wait cannot be satisfied
|
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immediately. The wait can also be specified as alertable.
|
|
|
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Arguments:
|
|
|
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Count - Supplies a count of the number of objects that are to be waited
|
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on.
|
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|
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Object[] - Supplies an array of pointers to dispatcher objects.
|
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|
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WaitType - Supplies the type of wait to perform (WaitAll, WaitAny).
|
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|
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WaitReason - Supplies the reason for the wait.
|
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|
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WaitMode - Supplies the processor mode in which the wait is to occur.
|
|
|
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Alertable - Supplies a boolean value that specifies whether the wait is
|
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alertable.
|
|
|
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Timeout - Supplies a pointer to an optional absolute of relative time over
|
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which the wait is to occur.
|
|
|
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WaitBlockArray - Supplies an optional pointer to an array of wait blocks
|
|
that are to used to describe the wait operation.
|
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|
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Return Value:
|
|
|
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The wait completion status. A value of STATUS_TIMEOUT is returned if a
|
|
timeout occurred. The index of the object (zero based) in the object
|
|
pointer array is returned if an object satisfied the wait. A value of
|
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STATUS_ALERTED is returned if the wait was aborted to deliver an alert
|
|
to the current thread. A value of STATUS_USER_APC is returned if the
|
|
wait was aborted to deliver a user APC to the current thread.
|
|
|
|
--*/
|
|
|
|
{
|
|
|
|
LARGE_INTEGER DueTime;
|
|
ULONG Index;
|
|
LARGE_INTEGER NewTime;
|
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PRKTHREAD NextThread;
|
|
PKMUTANT Objectx;
|
|
PLARGE_INTEGER OriginalTime;
|
|
PRKQUEUE Queue;
|
|
PRKTHREAD Thread;
|
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PRKTIMER Timer;
|
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PRKWAIT_BLOCK WaitBlock;
|
|
BOOLEAN WaitSatisfied;
|
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NTSTATUS WaitStatus;
|
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PKWAIT_BLOCK WaitTimer;
|
|
|
|
|
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// If the dispatcher database lock is not already held, then set the wait
|
|
// IRQL and lock the dispatcher database. Else set boolean wait variable
|
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// to FALSE.
|
|
|
|
|
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Thread = KeGetCurrentThread();
|
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if (Thread->WaitNext) {
|
|
Thread->WaitNext = FALSE;
|
|
|
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} else {
|
|
KiLockDispatcherDatabase(&Thread->WaitIrql);
|
|
}
|
|
|
|
|
|
// If a wait block array has been specified, then the maximum number of
|
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// objects that can be waited on is specified by MAXIMUM_WAIT_OBJECTS.
|
|
// Otherwise the builtin wait blocks in the thread object are used and
|
|
// the maximum number of objects that can be waited on is specified by
|
|
// THREAD_WAIT_OBJECTS. If the specified number of objects is not within
|
|
// limits, then bug check.
|
|
|
|
|
|
if (ARGUMENT_PRESENT(WaitBlockArray)) {
|
|
if (Count > MAXIMUM_WAIT_OBJECTS) {
|
|
KeBugCheck(MAXIMUM_WAIT_OBJECTS_EXCEEDED);
|
|
}
|
|
|
|
} else {
|
|
if (Count > THREAD_WAIT_OBJECTS) {
|
|
KeBugCheck(MAXIMUM_WAIT_OBJECTS_EXCEEDED);
|
|
}
|
|
|
|
WaitBlockArray = &Thread->WaitBlock[0];
|
|
}
|
|
|
|
|
|
// Start of wait loop.
|
|
|
|
// Note this loop is repeated if a kernel APC is delivered in the middle
|
|
// of the wait or a kernel APC is pending on the first attempt through
|
|
// the loop.
|
|
|
|
|
|
OriginalTime = Timeout;
|
|
do {
|
|
|
|
|
|
// Set address of wait block list in thread object.
|
|
|
|
|
|
Thread->WaitBlockList = WaitBlockArray;
|
|
|
|
|
|
// Test to determine if a kernel APC is pending.
|
|
|
|
// If a kernel APC is pending and the previous IRQL was less than
|
|
// APC_LEVEL, then a kernel APC was queued by another processor just
|
|
// after IRQL was raised to DISPATCH_LEVEL, but before the dispatcher
|
|
// database was locked.
|
|
|
|
// N.B. that this can only happen in a multiprocessor system.
|
|
|
|
|
|
if (Thread->ApcState.KernelApcPending && (Thread->WaitIrql < APC_LEVEL)) {
|
|
|
|
|
|
// Unlock the dispatcher database and lower IRQL to its previous
|
|
// value. An APC interrupt will immediately occur which will result
|
|
// in the delivery of the kernel APC if possible.
|
|
|
|
|
|
KiUnlockDispatcherDatabase(Thread->WaitIrql);
|
|
|
|
} else {
|
|
|
|
|
|
// Construct wait blocks and check to determine if the wait is
|
|
// already satisfied. If the wait is satisfied, then perform
|
|
// wait completion and return. Else put current thread in a wait
|
|
// state if an explicit timeout value of zero is not specified.
|
|
|
|
|
|
Thread->WaitStatus = (NTSTATUS)0;
|
|
WaitSatisfied = TRUE;
|
|
for (Index = 0; Index < Count; Index += 1) {
|
|
|
|
|
|
// Test if wait can be satisfied immediately.
|
|
|
|
|
|
Objectx = (PKMUTANT)Object[Index];
|
|
|
|
ASSERT(Objectx->Header.Type != QueueObject);
|
|
|
|
if (WaitType == WaitAny) {
|
|
|
|
|
|
// If the object is a mutant object and the mutant object
|
|
// has been recursively acquired MINLONG times, then raise
|
|
// an exception. Otherwise if the signal state of the mutant
|
|
// object is greater than zero, or the current thread is
|
|
// the owner of the mutant object, then satisfy the wait.
|
|
|
|
|
|
if (Objectx->Header.Type == MutantObject) {
|
|
if ((Objectx->Header.SignalState > 0) ||
|
|
(Thread == Objectx->OwnerThread)) {
|
|
if (Objectx->Header.SignalState != MINLONG) {
|
|
KiWaitSatisfyMutant(Objectx, Thread);
|
|
WaitStatus = (NTSTATUS)(Index | Thread->WaitStatus);
|
|
goto NoWait;
|
|
|
|
} else {
|
|
KiUnlockDispatcherDatabase(Thread->WaitIrql);
|
|
ExRaiseStatus(STATUS_MUTANT_LIMIT_EXCEEDED);
|
|
}
|
|
}
|
|
|
|
|
|
// If the signal state is greater than zero, then satisfy
|
|
// the wait.
|
|
|
|
|
|
} else if (Objectx->Header.SignalState > 0) {
|
|
KiWaitSatisfyOther(Objectx);
|
|
WaitStatus = (NTSTATUS)(Index);
|
|
goto NoWait;
|
|
}
|
|
|
|
} else {
|
|
|
|
|
|
// If the object is a mutant object and the mutant object
|
|
// has been recursively acquired MAXLONG times, then raise
|
|
// an exception. Otherwise if the signal state of the mutant
|
|
// object is less than or equal to zero and the current
|
|
// thread is not the owner of the mutant object, then the
|
|
// wait cannot be satisfied.
|
|
|
|
|
|
if (Objectx->Header.Type == MutantObject) {
|
|
if ((Thread == Objectx->OwnerThread) &&
|
|
(Objectx->Header.SignalState == MINLONG)) {
|
|
KiUnlockDispatcherDatabase(Thread->WaitIrql);
|
|
ExRaiseStatus(STATUS_MUTANT_LIMIT_EXCEEDED);
|
|
|
|
} else if ((Objectx->Header.SignalState <= 0) &&
|
|
(Thread != Objectx->OwnerThread)) {
|
|
WaitSatisfied = FALSE;
|
|
}
|
|
|
|
|
|
// If the signal state is less than or equal to zero, then
|
|
// the wait cannot be satisfied.
|
|
|
|
|
|
} else if (Objectx->Header.SignalState <= 0) {
|
|
WaitSatisfied = FALSE;
|
|
}
|
|
}
|
|
|
|
|
|
// Construct wait block for the current object.
|
|
|
|
|
|
WaitBlock = &WaitBlockArray[Index];
|
|
WaitBlock->Object = (PVOID)Objectx;
|
|
WaitBlock->WaitKey = (CSHORT)(Index);
|
|
WaitBlock->WaitType = (USHORT)WaitType;
|
|
WaitBlock->Thread = Thread;
|
|
WaitBlock->NextWaitBlock = &WaitBlockArray[Index + 1];
|
|
}
|
|
|
|
|
|
// If the wait type is wait all, then check to determine if the
|
|
// wait can be satisfied immediately.
|
|
|
|
|
|
if ((WaitType == WaitAll) && (WaitSatisfied)) {
|
|
WaitBlock->NextWaitBlock = &WaitBlockArray[0];
|
|
KiWaitSatisfyAll(WaitBlock);
|
|
WaitStatus = (NTSTATUS)Thread->WaitStatus;
|
|
goto NoWait;
|
|
}
|
|
|
|
|
|
// Test for alert pending.
|
|
|
|
|
|
TestForAlertPending(Alertable);
|
|
|
|
|
|
// The wait cannot be satisifed immediately. Check to determine if
|
|
// a timeout value is specified.
|
|
|
|
|
|
if (ARGUMENT_PRESENT(Timeout)) {
|
|
|
|
|
|
// If the timeout value is zero, then return immediately without
|
|
// waiting.
|
|
|
|
|
|
if (!(Timeout->LowPart | Timeout->HighPart)) {
|
|
WaitStatus = (NTSTATUS)(STATUS_TIMEOUT);
|
|
goto NoWait;
|
|
}
|
|
|
|
|
|
// Initialize a wait block for the thread specific timer,
|
|
// initialize timer wait list head, insert the timer in the
|
|
// timer tree, and increment the number of wait objects.
|
|
|
|
// N.B. The timer wait block is initialized when the respective
|
|
// thread is initialized. Thus the constant fields are not
|
|
// reinitialized. These include the wait object, wait key,
|
|
// wait type, and the wait list entry link pointers.
|
|
|
|
|
|
WaitTimer = &Thread->WaitBlock[TIMER_WAIT_BLOCK];
|
|
WaitBlock->NextWaitBlock = WaitTimer;
|
|
WaitBlock = WaitTimer;
|
|
Timer = &Thread->Timer;
|
|
InitializeListHead(&Timer->Header.WaitListHead);
|
|
if (KiInsertTreeTimer(Timer, *Timeout) == FALSE) {
|
|
WaitStatus = (NTSTATUS)STATUS_TIMEOUT;
|
|
goto NoWait;
|
|
}
|
|
|
|
DueTime.QuadPart = Timer->DueTime.QuadPart;
|
|
}
|
|
|
|
|
|
// Close up the circular list of wait control blocks.
|
|
|
|
|
|
WaitBlock->NextWaitBlock = &WaitBlockArray[0];
|
|
|
|
|
|
// Insert wait blocks in object wait lists.
|
|
|
|
|
|
WaitBlock = &WaitBlockArray[0];
|
|
do {
|
|
Objectx = (PKMUTANT)WaitBlock->Object;
|
|
InsertTailList(&Objectx->Header.WaitListHead, &WaitBlock->WaitListEntry);
|
|
WaitBlock = WaitBlock->NextWaitBlock;
|
|
} while (WaitBlock != &WaitBlockArray[0]);
|
|
|
|
|
|
// If the current thread is processing a queue entry, then attempt
|
|
// to activate another thread that is blocked on the queue object.
|
|
|
|
|
|
Queue = Thread->Queue;
|
|
if (Queue != NULL) {
|
|
KiActivateWaiterQueue(Queue);
|
|
}
|
|
|
|
|
|
// Set the thread wait parameters, set the thread dispatcher state
|
|
// to Waiting, and insert the thread in the wait list.
|
|
|
|
|
|
Thread->Alertable = Alertable;
|
|
Thread->WaitMode = WaitMode;
|
|
Thread->WaitReason = (UCHAR)WaitReason;
|
|
Thread->WaitTime= KiQueryLowTickCount();
|
|
Thread->State = Waiting;
|
|
KiInsertWaitList(WaitMode, Thread);
|
|
|
|
|
|
// Switch context to selected thread.
|
|
|
|
// Control is returned at the original IRQL.
|
|
|
|
|
|
ASSERT(Thread->WaitIrql <= DISPATCH_LEVEL);
|
|
|
|
WaitStatus = (NTSTATUS)KiSwapThread();
|
|
|
|
|
|
// If the thread was not awakened to deliver a kernel mode APC,
|
|
// then the wait status.
|
|
|
|
|
|
if (WaitStatus != STATUS_KERNEL_APC) {
|
|
return WaitStatus;
|
|
}
|
|
|
|
if (ARGUMENT_PRESENT(Timeout)) {
|
|
|
|
|
|
// Reduce the amount of time remaining before timeout occurs.
|
|
|
|
|
|
Timeout = KiComputeWaitInterval(OriginalTime,
|
|
&DueTime,
|
|
&NewTime);
|
|
}
|
|
}
|
|
|
|
|
|
// Raise IRQL to DISPATCH_LEVEL and lock the dispatcher database.
|
|
|
|
|
|
KiLockDispatcherDatabase(&Thread->WaitIrql);
|
|
} while (TRUE);
|
|
|
|
|
|
// The thread is alerted or a user APC should be delivered. Unlock the
|
|
// dispatcher database, lower IRQL to its previous value, and return
|
|
// the wait status.
|
|
|
|
|
|
KiUnlockDispatcherDatabase(Thread->WaitIrql);
|
|
return WaitStatus;
|
|
|
|
|
|
// The wait has been satisfied without actually waiting.
|
|
|
|
// If the thread priority that is less than time critical, then reduce
|
|
// the thread quantum. If a quantum end occurs, then reduce the thread
|
|
// priority.
|
|
|
|
|
|
NoWait:
|
|
KiAdjustQuantumThread(Thread);
|
|
|
|
|
|
// Unlock the dispatcher database, lower IRQL to its previous value, and
|
|
// return the wait status.
|
|
|
|
|
|
KiUnlockDispatcherDatabase(Thread->WaitIrql);
|
|
return WaitStatus;
|
|
}
|
|
|
|
NTSTATUS
|
|
KeWaitForSingleObject (
|
|
IN PVOID Object,
|
|
IN KWAIT_REASON WaitReason,
|
|
IN KPROCESSOR_MODE WaitMode,
|
|
IN BOOLEAN Alertable,
|
|
IN PLARGE_INTEGER Timeout OPTIONAL
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This function waits until the specified object attains a state of
|
|
Signaled. An optional timeout can also be specified. If a timeout
|
|
is not specified, then the wait will not be satisfied until the object
|
|
attains a state of Signaled. If a timeout is specified, and the object
|
|
has not attained a state of Signaled when the timeout expires, then
|
|
the wait is automatically satisfied. If an explicit timeout value of
|
|
zero is specified, then no wait will occur if the wait cannot be satisfied
|
|
immediately. The wait can also be specified as alertable.
|
|
|
|
Arguments:
|
|
|
|
Object - Supplies a pointer to a dispatcher object.
|
|
|
|
WaitReason - Supplies the reason for the wait.
|
|
|
|
WaitMode - Supplies the processor mode in which the wait is to occur.
|
|
|
|
Alertable - Supplies a boolean value that specifies whether the wait is
|
|
alertable.
|
|
|
|
Timeout - Supplies a pointer to an optional absolute of relative time over
|
|
which the wait is to occur.
|
|
|
|
Return Value:
|
|
|
|
The wait completion status. A value of STATUS_TIMEOUT is returned if a
|
|
timeout occurred. A value of STATUS_SUCCESS is returned if the specified
|
|
object satisfied the wait. A value of STATUS_ALERTED is returned if the
|
|
wait was aborted to deliver an alert to the current thread. A value of
|
|
STATUS_USER_APC is returned if the wait was aborted to deliver a user
|
|
APC to the current thread.
|
|
|
|
--*/
|
|
|
|
{
|
|
|
|
LARGE_INTEGER DueTime;
|
|
LARGE_INTEGER NewTime;
|
|
PRKTHREAD NextThread;
|
|
PKMUTANT Objectx;
|
|
PLARGE_INTEGER OriginalTime;
|
|
PRKQUEUE Queue;
|
|
PRKTHREAD Thread;
|
|
PRKTIMER Timer;
|
|
PKWAIT_BLOCK WaitBlock;
|
|
NTSTATUS WaitStatus;
|
|
PKWAIT_BLOCK WaitTimer;
|
|
|
|
|
|
// Collect call data.
|
|
|
|
|
|
#if defined(_COLLECT_WAIT_SINGLE_CALLDATA_)
|
|
|
|
RECORD_CALL_DATA(&KiWaitSingleCallData);
|
|
|
|
#endif
|
|
|
|
|
|
// If the dispatcher database lock is not already held, then set the wait
|
|
// IRQL and lock the dispatcher database. Else set boolean wait variable
|
|
// to FALSE.
|
|
|
|
|
|
Thread = KeGetCurrentThread();
|
|
if (Thread->WaitNext) {
|
|
Thread->WaitNext = FALSE;
|
|
|
|
} else {
|
|
KiLockDispatcherDatabase(&Thread->WaitIrql);
|
|
}
|
|
|
|
|
|
// Start of wait loop.
|
|
|
|
// Note this loop is repeated if a kernel APC is delivered in the middle
|
|
// of the wait or a kernel APC is pending on the first attempt through
|
|
// the loop.
|
|
|
|
|
|
OriginalTime = Timeout;
|
|
WaitBlock = &Thread->WaitBlock[0];
|
|
do {
|
|
|
|
|
|
// Test to determine if a kernel APC is pending.
|
|
|
|
// If a kernel APC is pending and the previous IRQL was less than
|
|
// APC_LEVEL, then a kernel APC was queued by another processor just
|
|
// after IRQL was raised to DISPATCH_LEVEL, but before the dispatcher
|
|
// database was locked.
|
|
|
|
// N.B. that this can only happen in a multiprocessor system.
|
|
|
|
|
|
if (Thread->ApcState.KernelApcPending && (Thread->WaitIrql < APC_LEVEL)) {
|
|
|
|
|
|
// Unlock the dispatcher database and lower IRQL to its previous
|
|
// value. An APC interrupt will immediately occur which will result
|
|
// in the delivery of the kernel APC if possible.
|
|
|
|
|
|
KiUnlockDispatcherDatabase(Thread->WaitIrql);
|
|
|
|
} else {
|
|
|
|
|
|
// Test if the wait can be immediately satisfied.
|
|
|
|
|
|
Objectx = (PKMUTANT)Object;
|
|
Thread->WaitStatus = (NTSTATUS)0;
|
|
|
|
ASSERT(Objectx->Header.Type != QueueObject);
|
|
|
|
|
|
// If the object is a mutant object and the mutant object has been
|
|
// recursively acquired MINLONG times, then raise an exception.
|
|
// Otherwise if the signal state of the mutant object is greater
|
|
// than zero, or the current thread is the owner of the mutant
|
|
// object, then satisfy the wait.
|
|
|
|
|
|
if (Objectx->Header.Type == MutantObject) {
|
|
if ((Objectx->Header.SignalState > 0) ||
|
|
(Thread == Objectx->OwnerThread)) {
|
|
if (Objectx->Header.SignalState != MINLONG) {
|
|
KiWaitSatisfyMutant(Objectx, Thread);
|
|
WaitStatus = (NTSTATUS)(Thread->WaitStatus);
|
|
goto NoWait;
|
|
|
|
} else {
|
|
KiUnlockDispatcherDatabase(Thread->WaitIrql);
|
|
ExRaiseStatus(STATUS_MUTANT_LIMIT_EXCEEDED);
|
|
}
|
|
}
|
|
|
|
|
|
// If the signal state is greater than zero, then satisfy the wait.
|
|
|
|
|
|
} else if (Objectx->Header.SignalState > 0) {
|
|
KiWaitSatisfyOther(Objectx);
|
|
WaitStatus = (NTSTATUS)(0);
|
|
goto NoWait;
|
|
}
|
|
|
|
|
|
// Construct a wait block for the object.
|
|
|
|
|
|
Thread->WaitBlockList = WaitBlock;
|
|
WaitBlock->Object = Object;
|
|
WaitBlock->WaitKey = (CSHORT)(STATUS_SUCCESS);
|
|
WaitBlock->WaitType = WaitAny;
|
|
|
|
|
|
// Test for alert pending.
|
|
|
|
|
|
TestForAlertPending(Alertable);
|
|
|
|
|
|
// The wait cannot be satisifed immediately. Check to determine if
|
|
// a timeout value is specified.
|
|
|
|
|
|
if (ARGUMENT_PRESENT(Timeout)) {
|
|
|
|
|
|
// If the timeout value is zero, then return immediately without
|
|
// waiting.
|
|
|
|
|
|
if (!(Timeout->LowPart | Timeout->HighPart)) {
|
|
WaitStatus = (NTSTATUS)(STATUS_TIMEOUT);
|
|
goto NoWait;
|
|
}
|
|
|
|
|
|
// Initialize a wait block for the thread specific timer, insert
|
|
// wait block in timer wait list, insert the timer in the timer
|
|
// tree.
|
|
|
|
// N.B. The timer wait block is initialized when the respective
|
|
// thread is initialized. Thus the constant fields are not
|
|
// reinitialized. These include the wait object, wait key,
|
|
// wait type, and the wait list entry link pointers.
|
|
|
|
|
|
Timer = &Thread->Timer;
|
|
WaitTimer = &Thread->WaitBlock[TIMER_WAIT_BLOCK];
|
|
WaitBlock->NextWaitBlock = WaitTimer;
|
|
Timer->Header.WaitListHead.Flink = &WaitTimer->WaitListEntry;
|
|
Timer->Header.WaitListHead.Blink = &WaitTimer->WaitListEntry;
|
|
WaitTimer->NextWaitBlock = WaitBlock;
|
|
if (KiInsertTreeTimer(Timer, *Timeout) == FALSE) {
|
|
WaitStatus = (NTSTATUS)STATUS_TIMEOUT;
|
|
goto NoWait;
|
|
}
|
|
|
|
DueTime.QuadPart = Timer->DueTime.QuadPart;
|
|
|
|
} else {
|
|
WaitBlock->NextWaitBlock = WaitBlock;
|
|
}
|
|
|
|
|
|
// Insert wait block in object wait list.
|
|
|
|
|
|
InsertTailList(&Objectx->Header.WaitListHead, &WaitBlock->WaitListEntry);
|
|
|
|
|
|
// If the current thread is processing a queue entry, then attempt
|
|
// to activate another thread that is blocked on the queue object.
|
|
|
|
|
|
Queue = Thread->Queue;
|
|
if (Queue != NULL) {
|
|
KiActivateWaiterQueue(Queue);
|
|
}
|
|
|
|
|
|
// Set the thread wait parameters, set the thread dispatcher state
|
|
// to Waiting, and insert the thread in the wait list.
|
|
|
|
|
|
Thread->Alertable = Alertable;
|
|
Thread->WaitMode = WaitMode;
|
|
Thread->WaitReason = (UCHAR)WaitReason;
|
|
Thread->WaitTime= KiQueryLowTickCount();
|
|
Thread->State = Waiting;
|
|
KiInsertWaitList(WaitMode, Thread);
|
|
|
|
|
|
// Switch context to selected thread.
|
|
|
|
// Control is returned at the original IRQL.
|
|
|
|
|
|
ASSERT(Thread->WaitIrql <= DISPATCH_LEVEL);
|
|
|
|
WaitStatus = (NTSTATUS)KiSwapThread();
|
|
|
|
|
|
// If the thread was not awakened to deliver a kernel mode APC,
|
|
// then return wait status.
|
|
|
|
|
|
if (WaitStatus != STATUS_KERNEL_APC) {
|
|
return WaitStatus;
|
|
}
|
|
|
|
if (ARGUMENT_PRESENT(Timeout)) {
|
|
|
|
|
|
// Reduce the amount of time remaining before timeout occurs.
|
|
|
|
|
|
Timeout = KiComputeWaitInterval(OriginalTime,
|
|
&DueTime,
|
|
&NewTime);
|
|
}
|
|
}
|
|
|
|
|
|
// Raise IRQL to DISPATCH_LEVEL and lock the dispatcher database.
|
|
|
|
|
|
KiLockDispatcherDatabase(&Thread->WaitIrql);
|
|
} while (TRUE);
|
|
|
|
|
|
// The thread is alerted or a user APC should be delivered. Unlock the
|
|
// dispatcher database, lower IRQL to its previous value, and return
|
|
// the wait status.
|
|
|
|
|
|
KiUnlockDispatcherDatabase(Thread->WaitIrql);
|
|
return WaitStatus;
|
|
|
|
|
|
// The wait has been satisfied without actually waiting.
|
|
|
|
// If the thread priority that is less than time critical, then reduce
|
|
// the thread quantum. If a quantum end occurs, then reduce the thread
|
|
// priority.
|
|
|
|
|
|
NoWait:
|
|
KiAdjustQuantumThread(Thread);
|
|
|
|
|
|
// Unlock the dispatcher database, lower IRQL to its previous value, and
|
|
// return the wait status.
|
|
|
|
|
|
KiUnlockDispatcherDatabase(Thread->WaitIrql);
|
|
return WaitStatus;
|
|
}
|
|
|
|
NTSTATUS
|
|
KiSetServerWaitClientEvent (
|
|
IN PKEVENT ServerEvent,
|
|
IN PKEVENT ClientEvent,
|
|
IN ULONG WaitMode
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This function sets the specified server event and waits on specified
|
|
client event. The wait is performed such that an optimal switch to
|
|
the waiting thread occurs if possible. No timeout is associated with
|
|
the wait, and thus, the issuing thread will wait until the client event
|
|
is signaled or an APC is delivered.
|
|
|
|
Arguments:
|
|
|
|
ServerEvent - Supplies a pointer to a dispatcher object of type event.
|
|
|
|
ClientEvent - Supplies a pointer to a dispatcher object of type event.
|
|
|
|
WaitMode - Supplies the processor mode in which the wait is to occur.
|
|
|
|
Return Value:
|
|
|
|
The wait completion status. A value of STATUS_SUCCESS is returned if
|
|
the specified object satisfied the wait. A value of STATUS_USER_APC is
|
|
returned if the wait was aborted to deliver a user APC to the current
|
|
thread.
|
|
|
|
--*/
|
|
|
|
{
|
|
|
|
|
|
// Set sever event and wait on client event atomically.
|
|
|
|
|
|
KeSetEvent(ServerEvent, EVENT_INCREMENT, TRUE);
|
|
return KeWaitForSingleObject(ClientEvent,
|
|
WrEventPair,
|
|
(KPROCESSOR_MODE)WaitMode,
|
|
FALSE,
|
|
NULL);
|
|
}
|
|
|
|
PLARGE_INTEGER
|
|
FASTCALL
|
|
KiComputeWaitInterval (
|
|
IN PLARGE_INTEGER OriginalTime,
|
|
IN PLARGE_INTEGER DueTime,
|
|
IN OUT PLARGE_INTEGER NewTime
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This function recomputes the wait interval after a thread has been
|
|
awakened to deliver a kernel APC.
|
|
|
|
Arguments:
|
|
|
|
OriginalTime - Supplies a pointer to the original timeout value.
|
|
|
|
DueTime - Supplies a pointer to the previous due time.
|
|
|
|
NewTime - Supplies a pointer to a variable that receives the
|
|
recomputed wait interval.
|
|
|
|
Return Value:
|
|
|
|
A pointer to the new time is returned as the function value.
|
|
|
|
--*/
|
|
|
|
{
|
|
|
|
|
|
// If the original wait time was absolute, then return the same
|
|
// absolute time. Otherwise, reduce the wait time remaining before
|
|
// the time delay expires.
|
|
|
|
|
|
if (OriginalTime->QuadPart >= 0) {
|
|
return OriginalTime;
|
|
|
|
} else {
|
|
KiQueryInterruptTime(NewTime);
|
|
NewTime->QuadPart -= DueTime->QuadPart;
|
|
return NewTime;
|
|
}
|
|
}
|