Leaked source code of windows server 2003
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/*
Copyright (c) 1992 Microsoft Corporation
Module Name:
atktimer.c
Abstract:
This file implements the timer routines used by the stack.
Author:
Jameel Hyder ([email protected])
Nikhil Kamkolkar ([email protected])
Revision History:
23 Feb 1993 Initial Version
Notes: Tab stop: 4
--*/
#include <atalk.h>
#pragma hdrstop
#define FILENUM ATKTIMER
// Discardable code after Init time
#ifdef ALLOC_PRAGMA
#pragma alloc_text(INIT, AtalkTimerInit)
#pragma alloc_text(PAGEINIT, AtalkTimerFlushAndStop)
#endif
/*** AtalkTimerInit
*
* Initialize the timer component for the appletalk stack.
*/
NTSTATUS
AtalkTimerInit(
VOID
)
{
BOOLEAN TimerStarted;
// Initialize the timer and its associated Dpc and kick it off
KeInitializeEvent(&atalkTimerStopEvent, NotificationEvent, FALSE);
KeInitializeTimer(&atalkTimer);
INITIALIZE_SPIN_LOCK(&atalkTimerLock);
KeInitializeDpc(&atalkTimerDpc, atalkTimerDpcRoutine, NULL);
atalkTimerTick.QuadPart = ATALK_TIMER_TICK;
TimerStarted = KeSetTimer(&atalkTimer,
atalkTimerTick,
&atalkTimerDpc);
ASSERT(!TimerStarted);
return STATUS_SUCCESS;
}
/*** AtalkTimerScheduleEvent
*
* Insert an event in the timer event list. If the list is empty, then
* fire off a timer. The time is specified in ticks. Each tick is currently
* 100ms. It may not be zero or negative. The internal timer also fires at
* 100ms granularity.
*/
VOID FASTCALL
AtalkTimerScheduleEvent(
IN PTIMERLIST pList // TimerList to use for queuing
)
{
KIRQL OldIrql;
DBGPRINT(DBG_COMP_SYSTEM, DBG_LEVEL_INFO,
("AtalkTimerScheduleEvent: pList %lx\n", pList));
ASSERT(VALID_TMR(pList));
ASSERT (pList->tmr_Routine != NULL);
ASSERT (pList->tmr_AbsTime != 0);
if (!atalkTimerStopped)
{
ACQUIRE_SPIN_LOCK(&atalkTimerLock, &OldIrql);
// Enqueue this handler
atalkTimerEnqueue(pList);
RELEASE_SPIN_LOCK(&atalkTimerLock, OldIrql);
}
else
{
DBGPRINT(DBG_COMP_SYSTEM, DBG_LEVEL_FATAL,
("AtalkTimerScheduleEvent: Called after Flush !!\n"));
}
}
/*** atalkTimerDpcRoutine
*
* This is called in at DISPATCH_LEVEL when the timer expires. The entry at
* the head of the list is decremented and if ZERO unlinked and dispatched.
* If the list is non-empty, the timer is fired again.
*/
LOCAL VOID
atalkTimerDpcRoutine(
IN PKDPC pKDpc,
IN PVOID pContext,
IN PVOID SystemArgument1,
IN PVOID SystemArgument2
)
{
PTIMERLIST pList;
BOOLEAN TimerStarted;
LONG ReQueue;
pKDpc; pContext; SystemArgument1; SystemArgument2;
if (atalkTimerStopped)
{
DBGPRINT(DBG_COMP_SYSTEM, DBG_LEVEL_ERR,
("atalkTimerDpc: Enetered after Flush !!!\n"));
return;
}
ACQUIRE_SPIN_LOCK_DPC(&atalkTimerLock);
AtalkTimerCurrentTick ++; // Update our relative time
// We should never be here if we have no work to do
if ((atalkTimerList != NULL))
{
// Careful here. If two guys wanna go off together - let them !!
if (atalkTimerList->tmr_RelDelta != 0)
(atalkTimerList->tmr_RelDelta)--;
// Dispatch the entry if it is ready to go
pList = atalkTimerList;
if (pList->tmr_RelDelta == 0)
{
ASSERT(VALID_TMR(pList));
// Unlink from the list
// AtalkUnlinkDouble(pList, tmr_Next, tmr_Prev);
atalkTimerList = pList->tmr_Next;
if (atalkTimerList != NULL)
atalkTimerList->tmr_Prev = &atalkTimerList;
pList->tmr_Queued = FALSE;
pList->tmr_Running = TRUE;
atalkTimerRunning = TRUE;
DBGPRINT(DBG_COMP_SYSTEM, DBG_LEVEL_INFO,
("atalkTimerDpcRoutine: Dispatching %lx\n", pList->tmr_Routine));
RELEASE_SPIN_LOCK_DPC(&atalkTimerLock);
ReQueue = (*pList->tmr_Routine)(pList, FALSE);
ACQUIRE_SPIN_LOCK_DPC(&atalkTimerLock);
atalkTimerRunning = FALSE;
if (ReQueue != ATALK_TIMER_NO_REQUEUE)
{
ASSERT(VALID_TMR(pList));
pList->tmr_Running = FALSE;
if (pList->tmr_CancelIt)
{
DBGPRINT(DBG_COMP_SYSTEM, DBG_LEVEL_INFO,
("atalkTimerDpcRoutine: Delayed cancel for %lx\n", pList));
RELEASE_SPIN_LOCK_DPC(&atalkTimerLock);
ReQueue = (*pList->tmr_Routine)(pList, TRUE);
ACQUIRE_SPIN_LOCK_DPC(&atalkTimerLock);
ASSERT(ReQueue == ATALK_TIMER_NO_REQUEUE);
}
else
{
if (ReQueue != ATALK_TIMER_REQUEUE)
pList->tmr_AbsTime = (USHORT)ReQueue;
atalkTimerEnqueue(pList);
}
}
}
}
RELEASE_SPIN_LOCK_DPC(&atalkTimerLock);
if (!atalkTimerStopped)
{
TimerStarted = KeSetTimer(&atalkTimer,
atalkTimerTick,
&atalkTimerDpc);
ASSERT(!TimerStarted);
}
else
{
KeSetEvent(&atalkTimerStopEvent, IO_NETWORK_INCREMENT, FALSE);
}
}
/*** atalkTimerEnqueue
*
* Here is a thesis on the code that follows.
*
* The timer events are maintained as a list which the timer dpc routine
* looks at every timer tick. The list is maintained in such a way that only
* the head of the list needs to be updated every tick i.e. the entire list
* is never scanned. The way this is achieved is by keeping delta times
* relative to the previous entry.
*
* Every timer tick, the relative time at the head of the list is decremented.
* When that goes to ZERO, the head of the list is unlinked and dispatched.
*
* To give an example, we have the following events queued at time slots
* X Schedule A after 10 ticks.
* X+3 Schedule B after 5 ticks.
* X+5 Schedule C after 4 ticks.
* X+8 Schedule D after 6 ticks.
*
* So A will schedule at X+10, B at X+8 (X+3+5), C at X+9 (X+5+4) and
* D at X+14 (X+8+6).
*
* The above example covers all the situations.
*
* - NULL List.
* - Inserting at head of list.
* - Inserting in the middle of the list.
* - Appending to the list tail.
*
* The list will look as follows.
*
* BEFORE AFTER
* ------ -----
*
* X Head -->| Head -> A(10) ->|
* A(10)
*
* X+3 Head -> A(7) ->| Head -> B(5) -> A(2) ->|
* B(5)
*
* X+5 Head -> B(3) -> A(2) ->| Head -> B(3) -> C(1) -> A(1) ->|
* C(4)
*
* X+8 Head -> C(1) -> A(1) ->| Head -> C(1) -> A(1) -> D(4) ->|
* D(6)
*
* The granularity is one tick. THIS MUST BE CALLED WITH THE TIMER LOCK HELD.
*/
VOID FASTCALL
atalkTimerEnqueue(
IN PTIMERLIST pListNew
)
{
PTIMERLIST pList, *ppList;
USHORT DeltaTime = pListNew->tmr_AbsTime;
// The DeltaTime is adjusted in every pass of the loop to reflect the
// time after the previous entry that the new entry will schedule.
for (ppList = &atalkTimerList;
(pList = *ppList) != NULL;
ppList = &pList->tmr_Next)
{
ASSERT(VALID_TMR(pList));
if (DeltaTime <= pList->tmr_RelDelta)
{
pList->tmr_RelDelta -= DeltaTime;
break;
}
DeltaTime -= pList->tmr_RelDelta;
}
// Link this in the chain
pListNew->tmr_RelDelta = DeltaTime;
pListNew->tmr_Next = pList;
pListNew->tmr_Prev = ppList;
*ppList = pListNew;
if (pList != NULL)
{
pList->tmr_Prev = &pListNew->tmr_Next;
}
pListNew->tmr_Queued = TRUE;
pListNew->tmr_Cancelled = FALSE;
pListNew->tmr_CancelIt = FALSE;
}
/*** AtalkTimerFlushAndStop
*
* Force all entries in the timer queue to be dispatched immediately. No
* more queue'ing of timer routines is permitted after this. The timer
* essentially shuts down.
*/
VOID
AtalkTimerFlushAndStop(
VOID
)
{
PTIMERLIST pList;
LONG ReQueue;
KIRQL OldIrql;
BOOLEAN Wait;
ASSERT (KeGetCurrentIrql() == LOW_LEVEL);
DBGPRINT(DBG_COMP_SYSTEM, DBG_LEVEL_ERR,
("AtalkTimerFlushAndStop: Entered\n"));
KeCancelTimer(&atalkTimer);
// The timer routines assume they are being called at DISPATCH level.
// Raise our Irql for this routine.
KeRaiseIrql(DISPATCH_LEVEL, &OldIrql);
ACQUIRE_SPIN_LOCK_DPC(&atalkTimerLock);
atalkTimerStopped = TRUE;
Wait = atalkTimerRunning;
// Dispatch all entries right away
while (atalkTimerList != NULL)
{
pList = atalkTimerList;
ASSERT(VALID_TMR(pList));
atalkTimerList = pList->tmr_Next;
DBGPRINT(DBG_COMP_SYSTEM, DBG_LEVEL_INFO,
("atalkTimerFlushAndStop: Dispatching %lx\n",
pList->tmr_Routine));
pList->tmr_Queued = FALSE;
pList->tmr_Running = TRUE;
RELEASE_SPIN_LOCK_DPC(&atalkTimerLock);
ReQueue = (*pList->tmr_Routine)(pList, TRUE);
ASSERT (ReQueue == ATALK_TIMER_NO_REQUEUE);
pList->tmr_Running = FALSE;
ACQUIRE_SPIN_LOCK_DPC(&atalkTimerLock);
}
RELEASE_SPIN_LOCK_DPC(&atalkTimerLock);
KeLowerIrql(OldIrql);
if (Wait)
{
// Wait for any timer events that are currently running. Only an MP issue
KeWaitForSingleObject(&atalkTimerStopEvent,
Executive,
KernelMode,
TRUE,
NULL);
}
}
/*** AtalkTimerCancelEvent
*
* Cancel a previously scheduled timer event, if it hasn't fired already.
*/
BOOLEAN FASTCALL
AtalkTimerCancelEvent(
IN PTIMERLIST pList,
IN PDWORD pdwOldState
)
{
KIRQL OldIrql;
BOOLEAN Cancelled = FALSE;
DWORD OldState=ATALK_TIMER_QUEUED;
ACQUIRE_SPIN_LOCK(&atalkTimerLock, &OldIrql);
// If this is not running, unlink it from the list
// adjusting relative deltas carefully
if (pList->tmr_Queued)
{
ASSERT (!(pList->tmr_Running));
OldState = ATALK_TIMER_QUEUED;
if (pList->tmr_Next != NULL)
{
pList->tmr_Next->tmr_RelDelta += pList->tmr_RelDelta;
pList->tmr_Next->tmr_Prev = pList->tmr_Prev;
}
*(pList->tmr_Prev) = pList->tmr_Next;
// pointing to timer being removed? fix it!
if (atalkTimerList == pList)
{
atalkTimerList = pList->tmr_Next;
}
Cancelled = pList->tmr_Cancelled = TRUE;
pList->tmr_Queued = FALSE;
}
else if (pList->tmr_Running)
{
DBGPRINT(DBG_COMP_SYSTEM, DBG_LEVEL_ERR,
("AtalkTimerCancelEvent: %lx Running, cancel set\n",
pList->tmr_Routine));
pList->tmr_CancelIt = TRUE; // Set to cancel after handler returns.
OldState = ATALK_TIMER_RUNNING;
}
RELEASE_SPIN_LOCK(&atalkTimerLock, OldIrql);
if (pdwOldState)
{
*pdwOldState = OldState;
}
return Cancelled;
}
#if DBG
VOID
AtalkTimerDumpList(
VOID
)
{
PTIMERLIST pList;
ULONG CumTime = 0;
DBGPRINT(DBG_COMP_DUMP, DBG_LEVEL_FATAL,
("TIMER LIST: (Times are in 100ms units)\n"));
DBGPRINT(DBG_COMP_DUMP, DBG_LEVEL_FATAL,
("\tTime(Abs) Time(Rel) Routine Address TimerList\n"));
ACQUIRE_SPIN_LOCK_DPC(&atalkTimerLock);
for (pList = atalkTimerList;
pList != NULL;
pList = pList->tmr_Next)
{
CumTime += pList->tmr_RelDelta;
DBGPRINT(DBG_COMP_DUMP, DBG_LEVEL_FATAL,
("\t %5d %5ld %lx %lx\n",
pList->tmr_AbsTime, CumTime,
pList->tmr_Routine, pList));
}
RELEASE_SPIN_LOCK_DPC(&atalkTimerLock);
}
#endif