Leaked source code of windows server 2003
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/*++
Copyright (c) 2000 Microsoft Corporation
Module Name:
cancelapi.c
Abstract:
This module contains the cancel safe DDI set
Author:
Nar Ganapathy (narg) 1-Jan-1999
Environment:
Kernel mode
Revision History:
--*/
#include "iomgr.h"
//
// The library exposes everything with the name "Wdmlib". This ensures drivers
// using the backward compatible Cancel DDI Lib won't opportunistically pick
// up the kernel exports just because they were built using the XP DDK.
//
#if CSQLIB
#define CSQLIB_DDI(x) Wdmlib##x
#else
#define CSQLIB_DDI(x) x
#endif
VOID
IopCsqCancelRoutine(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp
)
/*++
Routine Description:
This routine removes the IRP that's associated with a context from the queue.
It's expected that this routine will be called from a timer or DPC or other threads which complete an
IO. Note that the IRP associated with this context could already have been freed.
Arguments:
Csq - Pointer to the cancel queue.
Context - Context associated with Irp.
Return Value:
Returns the IRP associated with the context. If the value is not NULL, the IRP was successfully
retrieved and can be used safely. If the value is NULL, the IRP was already canceled.
--*/
{
KIRQL irql;
PIO_CSQ_IRP_CONTEXT irpContext;
PIO_CSQ cfq;
UNREFERENCED_PARAMETER (DeviceObject);
IoReleaseCancelSpinLock(Irp->CancelIrql);
irpContext = Irp->Tail.Overlay.DriverContext[3];
if (irpContext->Type == IO_TYPE_CSQ_IRP_CONTEXT) {
cfq = irpContext->Csq;
} else if ((irpContext->Type == IO_TYPE_CSQ) ||
(irpContext->Type == IO_TYPE_CSQ_EX)) {
cfq = (PIO_CSQ)irpContext;
} else {
//
// Bad type
//
ASSERT(0);
return;
}
ASSERT(cfq);
cfq->ReservePointer = NULL; // Force drivers to be good citizens
cfq->CsqAcquireLock(cfq, &irql);
cfq->CsqRemoveIrp(cfq, Irp);
//
// Break the association if necessary.
//
if (irpContext != (PIO_CSQ_IRP_CONTEXT)cfq) {
irpContext->Irp = NULL;
Irp->Tail.Overlay.DriverContext[3] = NULL;
}
cfq->CsqReleaseLock(cfq, irql);
cfq->CsqCompleteCanceledIrp(cfq, Irp);
}
NTSTATUS
CSQLIB_DDI(IoCsqInitialize)(
IN PIO_CSQ Csq,
IN PIO_CSQ_INSERT_IRP CsqInsertIrp,
IN PIO_CSQ_REMOVE_IRP CsqRemoveIrp,
IN PIO_CSQ_PEEK_NEXT_IRP CsqPeekNextIrp,
IN PIO_CSQ_ACQUIRE_LOCK CsqAcquireLock,
IN PIO_CSQ_RELEASE_LOCK CsqReleaseLock,
IN PIO_CSQ_COMPLETE_CANCELED_IRP CsqCompleteCanceledIrp
)
/*++
Routine Description:
This routine initializes the Cancel queue
Arguments:
Csq - Pointer to the cancel queue.
Return Value:
The function returns STATUS_SUCCESS on successful initialization
--*/
{
Csq->CsqInsertIrp = CsqInsertIrp;
Csq->CsqRemoveIrp = CsqRemoveIrp;
Csq->CsqPeekNextIrp = CsqPeekNextIrp;
Csq->CsqAcquireLock = CsqAcquireLock;
Csq->CsqReleaseLock = CsqReleaseLock;
Csq->CsqCompleteCanceledIrp = CsqCompleteCanceledIrp;
Csq->ReservePointer = NULL;
Csq->Type = IO_TYPE_CSQ;
return STATUS_SUCCESS;
}
NTSTATUS
CSQLIB_DDI(IoCsqInitializeEx)(
IN PIO_CSQ Csq,
IN PIO_CSQ_INSERT_IRP_EX CsqInsertIrp,
IN PIO_CSQ_REMOVE_IRP CsqRemoveIrp,
IN PIO_CSQ_PEEK_NEXT_IRP CsqPeekNextIrp,
IN PIO_CSQ_ACQUIRE_LOCK CsqAcquireLock,
IN PIO_CSQ_RELEASE_LOCK CsqReleaseLock,
IN PIO_CSQ_COMPLETE_CANCELED_IRP CsqCompleteCanceledIrp
)
/*++
Routine Description:
This routine initializes the Cancel queue
Arguments:
Csq - Pointer to the cancel queue.
Return Value:
The function returns STATUS_SUCCESS on successful initialization
--*/
{
Csq->CsqInsertIrp = (PIO_CSQ_INSERT_IRP)CsqInsertIrp;
Csq->CsqRemoveIrp = CsqRemoveIrp;
Csq->CsqPeekNextIrp = CsqPeekNextIrp;
Csq->CsqAcquireLock = CsqAcquireLock;
Csq->CsqReleaseLock = CsqReleaseLock;
Csq->CsqCompleteCanceledIrp = CsqCompleteCanceledIrp;
Csq->ReservePointer = NULL;
Csq->Type = IO_TYPE_CSQ_EX;
return STATUS_SUCCESS;
}
NTSTATUS
CSQLIB_DDI(IoCsqInsertIrpEx)(
IN PIO_CSQ Csq,
IN PIRP Irp,
IN PIO_CSQ_IRP_CONTEXT Context,
IN PVOID InsertContext
)
/*++
Routine Description:
This routine inserts the IRP into the queue and associates the context with the IRP.
The context has to be in non-paged pool if the context will be used in a DPC or interrupt routine.
The routine assumes that Irp->Tail.Overlay.DriverContext[3] is available for use by the APIs.
It's ok to pass a NULL context if the driver assumes that it will always use IoCsqRemoveNextIrp to
remove an IRP.
Arguments:
Csq - Pointer to the cancel queue.
Irp - Irp to be inserted
Context - Context to be associated with Irp.
InsertContext - Context passed to the driver's insert IRP routine.
Return Value:
NTSTATUS - Status returned by the driver's insert IRP routine. If the driver's insert IRP
routine returns an error status, the IRP is not inserted and the same status is returned
by this API. This allows drivers to implement startIo kind of functionality.
--*/
{
KIRQL irql;
PDRIVER_CANCEL cancelRoutine;
PVOID originalDriverContext;
NTSTATUS status = STATUS_SUCCESS;
//
// Set the association between the context and the IRP.
//
if (Context) {
Irp->Tail.Overlay.DriverContext[3] = Context;
Context->Irp = Irp;
Context->Csq = Csq;
Context->Type = IO_TYPE_CSQ_IRP_CONTEXT;
} else {
Irp->Tail.Overlay.DriverContext[3] = Csq;
}
Csq->ReservePointer = NULL; // Force drivers to be good citizens
originalDriverContext = Irp->Tail.Overlay.DriverContext[3];
Csq->CsqAcquireLock(Csq, &irql);
//
// If the driver wants to fail the insert then do this.
//
if (Csq->Type == IO_TYPE_CSQ_EX) {
PIO_CSQ_INSERT_IRP_EX func;
func = (PIO_CSQ_INSERT_IRP_EX)Csq->CsqInsertIrp;
status = func(Csq, Irp, InsertContext);
if (!NT_SUCCESS(status)) {
Csq->CsqReleaseLock(Csq, irql);
return status;
}
} else {
Csq->CsqInsertIrp(Csq, Irp);
}
IoMarkIrpPending(Irp);
cancelRoutine = IoSetCancelRoutine(Irp, IopCsqCancelRoutine);
ASSERT(!cancelRoutine);
if (Irp->Cancel) {
cancelRoutine = IoSetCancelRoutine(Irp, NULL);
if (cancelRoutine) {
Csq->CsqRemoveIrp(Csq, Irp);
if (Context) {
Context->Irp = NULL;
}
Irp->Tail.Overlay.DriverContext[3] = NULL;
Csq->CsqReleaseLock(Csq, irql);
Csq->CsqCompleteCanceledIrp(Csq, Irp);
} else {
//
// The cancel routine beat us to it.
//
Csq->CsqReleaseLock(Csq, irql);
}
} else {
Csq->CsqReleaseLock(Csq, irql);
}
return status;
}
VOID
CSQLIB_DDI(IoCsqInsertIrp)(
IN PIO_CSQ Csq,
IN PIRP Irp,
IN PIO_CSQ_IRP_CONTEXT Context
)
{
(VOID)CSQLIB_DDI(IoCsqInsertIrpEx)(Csq, Irp, Context, NULL);
}
PIRP
CSQLIB_DDI(IoCsqRemoveNextIrp)(
IN PIO_CSQ Csq,
IN PVOID PeekContext
)
/*++
Routine Description:
This routine removes the next IRP from the queue. This routine will enumerate the queue
and return an IRP that's not canceled. If an IRP in the queue is canceled it goes to the next
IRP. If no IRP is available it returns a NULL. The IRP returned is safe and cannot be canceled.
Arguments:
Csq - Pointer to the cancel queue.
Return Value:
Returns the IRP or NULL.
--*/
{
KIRQL irql;
PIO_CSQ_IRP_CONTEXT context;
PDRIVER_CANCEL cancelRoutine;
PIRP irp;
irp = NULL;
Csq->ReservePointer = NULL; // Force drivers to be good citizens
Csq->CsqAcquireLock(Csq, &irql);
irp = Csq->CsqPeekNextIrp(Csq, NULL, PeekContext);
while (1) {
//
// This routine will return a pointer to the next IRP in the queue adjacent to
// the irp passed as a parameter. If the irp is NULL, it returns the IRP at the head of
// the queue.
//
if (!irp) {
Csq->CsqReleaseLock(Csq, irql);
return NULL;
}
cancelRoutine = IoSetCancelRoutine(irp, NULL);
if (!cancelRoutine) {
irp = Csq->CsqPeekNextIrp(Csq, irp, PeekContext);
continue;
}
Csq->CsqRemoveIrp(Csq, irp); // Remove this IRP from the queue
break;
}
context = irp->Tail.Overlay.DriverContext[3];
if (context->Type == IO_TYPE_CSQ_IRP_CONTEXT) {
context->Irp = NULL;
ASSERT(context->Csq == Csq);
}
irp->Tail.Overlay.DriverContext[3] = NULL;
Csq->CsqReleaseLock(Csq, irql);
return irp;
}
PIRP
CSQLIB_DDI(IoCsqRemoveIrp)(
IN PIO_CSQ Csq,
IN PIO_CSQ_IRP_CONTEXT Context
)
/*++
Routine Description:
This routine removes the IRP that's associated with a context from the queue.
It's expected that this routine will be called from a timer or DPC or other threads which complete an
IO. Note that the IRP associated with this context could already have been freed.
Arguments:
Csq - Pointer to the cancel queue.
Context - Context associated with Irp.
Return Value:
Returns the IRP associated with the context. If the value is not NULL, the IRP was successfully
retrieved and can be used safely. If the value is NULL, the IRP was already canceled.
--*/
{
KIRQL irql;
PIRP irp;
PDRIVER_CANCEL cancelRoutine;
Csq->ReservePointer = NULL; // Force drivers to be good citizens
Csq->CsqAcquireLock(Csq, &irql);
if (Context->Irp ) {
ASSERT(Context->Csq == Csq);
irp = Context->Irp;
cancelRoutine = IoSetCancelRoutine(irp, NULL);
if (!cancelRoutine) {
Csq->CsqReleaseLock(Csq, irql);
return NULL;
}
ASSERT(Context == irp->Tail.Overlay.DriverContext[3]);
Csq->CsqRemoveIrp(Csq, irp);
//
// Break the association.
//
Context->Irp = NULL;
irp->Tail.Overlay.DriverContext[3] = NULL;
ASSERT(Context->Csq == Csq);
Csq->CsqReleaseLock(Csq, irql);
return irp;
} else {
Csq->CsqReleaseLock(Csq, irql);
return NULL;
}
}