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WindowsXP-SP1/base/fs/npfs/waitsup.c

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2001-01-01 00:00:00 +01:00
/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
WaitSup.c
Abstract:
This module implements the Wait for Named Pipe support routines.
Author:
Gary Kimura [GaryKi] 30-Aug-1990
Revision History:
--*/
#include "NpProcs.h"
//
// The debug trace level
//
#define Dbg (DEBUG_TRACE_WAITSUP)
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, NpInitializeWaitQueue)
#pragma alloc_text(PAGE, NpUninitializeWaitQueue)
#endif
//
// Local procedures and structures
//
typedef struct _WAIT_CONTEXT {
PIRP Irp;
KDPC Dpc;
KTIMER Timer;
PWAIT_QUEUE WaitQueue;
UNICODE_STRING TranslatedString;
PFILE_OBJECT FileObject;
} WAIT_CONTEXT;
typedef WAIT_CONTEXT *PWAIT_CONTEXT;
VOID
NpInitializeWaitQueue (
IN PWAIT_QUEUE WaitQueue
)
/*++
Routine Description:
This routine initializes the wait for named pipe queue.
Arguments:
WaitQueue - Supplies a pointer to the list head being initialized
Return Value:
None.
--*/
{
PAGED_CODE();
DebugTrace(+1, Dbg, "NpInitializeWaitQueue, WaitQueue = %08lx\n", WaitQueue);
//
// Initialize the List head
//
InitializeListHead( &WaitQueue->Queue );
//
// Initialize the Wait Queue's spinlock
//
KeInitializeSpinLock( &WaitQueue->SpinLock );
//
// and return to our caller
//
DebugTrace(-1, Dbg, "NpInitializeWaitQueue -> VOID\n", 0);
return;
}
VOID
NpUninitializeWaitQueue (
IN PWAIT_QUEUE WaitQueue
)
/*++
Routine Description:
This routine uninitializes the wait for named pipe queue.
Arguments:
WaitQueue - Supplies a pointer to the list head being uninitialized
Return Value:
None.
--*/
{
PAGED_CODE();
DebugTrace(+1, Dbg, "NpInitializeWaitQueue, WaitQueue = %08lx\n", WaitQueue);
//
// And return to our caller
//
DebugTrace(-1, Dbg, "NpInitializeWaitQueue -> VOID\n", 0);
return;
}
NTSTATUS
NpAddWaiter (
IN PWAIT_QUEUE WaitQueue,
IN LARGE_INTEGER DefaultTimeOut,
IN PIRP Irp,
IN PUNICODE_STRING TranslatedString
)
/*++
Routine Description:
This routine adds a new "wait for named pipe" IRP to the wait queue.
After calling this function the caller nolonger can access the IRP
Arguments:
WaitQueue - Supplies the wait queue being used
DefaultTimeOut - Supplies the default time out to use if one is
not supplied in the Irp
Irp - Supplies a pointer to the wait Irp
TranslatedString - If not NULL points to the translated string
Return Value:
None.
--*/
{
KIRQL OldIrql;
PWAIT_CONTEXT Context;
PFILE_PIPE_WAIT_FOR_BUFFER WaitForBuffer;
LARGE_INTEGER Timeout;
ULONG i;
NTSTATUS status;
PIO_STACK_LOCATION IrpSp;
DebugTrace(+1, Dbg, "NpAddWaiter, WaitQueue = %08lx\n", WaitQueue);
IrpSp = IoGetCurrentIrpStackLocation (Irp);
//
// Allocate a dpc and timer structure and initialize them
//
Context = NpAllocateNonPagedPoolWithQuota( sizeof(WAIT_CONTEXT), 'wFpN' );
if (Context == NULL) {
return STATUS_INSUFFICIENT_RESOURCES;
}
KeInitializeDpc( &Context->Dpc, NpTimerDispatch, Context );
KeInitializeTimer( &Context->Timer );
if (TranslatedString) {
Context->TranslatedString = (*TranslatedString);
} else {
Context->TranslatedString.Length = 0;
Context->TranslatedString.Buffer = NULL;
}
Context->WaitQueue = WaitQueue;
Context->Irp = Irp;
//
// Figure out our timeout value
//
WaitForBuffer = (PFILE_PIPE_WAIT_FOR_BUFFER)Irp->AssociatedIrp.SystemBuffer;
if (WaitForBuffer->TimeoutSpecified) {
Timeout = WaitForBuffer->Timeout;
} else {
Timeout = DefaultTimeOut;
}
//
// Upcase the name of the pipe we are waiting for
//
for (i = 0; i < WaitForBuffer->NameLength/sizeof(WCHAR); i += 1) {
WaitForBuffer->Name[i] = RtlUpcaseUnicodeChar(WaitForBuffer->Name[i]);
}
NpIrpWaitQueue(Irp) = WaitQueue;
NpIrpWaitContext(Irp) = Context;
//
// Acquire the spinlock
//
KeAcquireSpinLock( &WaitQueue->SpinLock, &OldIrql );
//
// Now set the cancel routine for the irp and check if it has been cancelled.
//
IoSetCancelRoutine( Irp, NpCancelWaitQueueIrp );
if (Irp->Cancel && IoSetCancelRoutine( Irp, NULL ) != NULL) {
status = STATUS_CANCELLED;
} else {
//
// Now insert this new entry into the Wait Queue
//
InsertTailList( &WaitQueue->Queue, &Irp->Tail.Overlay.ListEntry );
IoMarkIrpPending (Irp);
//
// The DPC routine may run without an IRP if it gets completed before it runs. To keep the WaitQueue
// valid we need a file object reference. This is an unload issue becuase the wait queue is in the VCB.
//
Context->FileObject = IrpSp->FileObject;
ObReferenceObject (IrpSp->FileObject);
//
// And set the timer to go off
//
(VOID)KeSetTimer( &Context->Timer, Timeout, &Context->Dpc );
Context = NULL;
status = STATUS_PENDING;
}
//
// Release the spinlock
//
KeReleaseSpinLock( &WaitQueue->SpinLock, OldIrql );
if (Context != NULL) {
NpFreePool (Context);
}
//
// And now return to our caller
//
DebugTrace(-1, Dbg, "NpAddWaiter -> VOID\n", 0);
return status;
}
NTSTATUS
NpCancelWaiter (
IN PWAIT_QUEUE WaitQueue,
IN PUNICODE_STRING NameOfPipe,
IN NTSTATUS Completionstatus,
IN PLIST_ENTRY DeferredList
)
/*++
Routine Description:
This procedure cancels all waiters that are waiting for the named
pipe to reach the listening state. The corresponding IRPs are completed
with Completionstatus.
Arguments:
WaitQueue - Supplies the wait queue being modified
NameOfPipe - Supplies the name of the named pipe (device relative)
that has just reached the listening state.
CompletionStatus - Status to complete IRPs with
DeferredList - List or IRPs to complete once we drop locks
Return Value:
None.
--*/
{
KIRQL OldIrql;
PLIST_ENTRY Links;
PIRP Irp;
PFILE_PIPE_WAIT_FOR_BUFFER WaitForBuffer;
PWAIT_CONTEXT Context, ContextList= NULL;
ULONG i;
BOOLEAN SuccessfullMatch = FALSE;
UNICODE_STRING NonPagedNameOfPipe;
DebugTrace(+1, Dbg, "NpCancelWaiter, WaitQueue = %08lx\n", WaitQueue);
//
// Capture the name of pipe before we grab the spinlock, and upcase it
//
NonPagedNameOfPipe.Buffer = NpAllocateNonPagedPool( NameOfPipe->Length, 'tFpN' );
if (NonPagedNameOfPipe.Buffer == NULL) {
return STATUS_INSUFFICIENT_RESOURCES;
}
NonPagedNameOfPipe.Length = 0;
NonPagedNameOfPipe.MaximumLength = NameOfPipe->Length;
(VOID) RtlUpcaseUnicodeString( &NonPagedNameOfPipe, NameOfPipe, FALSE );
//
// Acquire the spinlock
//
KeAcquireSpinLock( &WaitQueue->SpinLock, &OldIrql );
//
// For each waiting irp check if the name matches
//
for (Links = WaitQueue->Queue.Flink;
Links != &WaitQueue->Queue;
Links = Links->Flink) {
Irp = CONTAINING_RECORD( Links, IRP, Tail.Overlay.ListEntry );
WaitForBuffer = (PFILE_PIPE_WAIT_FOR_BUFFER)Irp->AssociatedIrp.SystemBuffer;
Context = NpIrpWaitContext(Irp);
//
// Check if this Irp matches the one we've been waiting for
// First check the lengths for equality, and then compare
// the strings. They match if we exit the inner loop with
// i >= name length.
//
SuccessfullMatch = FALSE;
if (Context->TranslatedString.Length ) {
if (NonPagedNameOfPipe.Length == Context->TranslatedString.Length) {
if (RtlEqualMemory(Context->TranslatedString.Buffer, NonPagedNameOfPipe.Buffer, NonPagedNameOfPipe.Length)) {
SuccessfullMatch = TRUE;
}
}
} else {
if (((USHORT)(WaitForBuffer->NameLength + sizeof(WCHAR))) == NonPagedNameOfPipe.Length) {
for (i = 0; i < WaitForBuffer->NameLength/sizeof(WCHAR); i += 1) {
if (WaitForBuffer->Name[i] != NonPagedNameOfPipe.Buffer[i+1]) {
break;
}
}
if (i >= WaitForBuffer->NameLength/sizeof(WCHAR)) {
SuccessfullMatch = TRUE;
}
}
}
if (SuccessfullMatch) {
Links = Links->Blink;
RemoveEntryList( &Irp->Tail.Overlay.ListEntry );
//
// Attempt to stop the timer. If its already running then it must be stalled before obtaining
// this spinlock or it would have removed this item from the list. Break the link between the timer
// context and the IRP in this case and let it run on.
//
if (KeCancelTimer( &Context->Timer )) {
//
// Time got stopped. The context gets freed below after we drop the lock.
//
Context->WaitQueue = (PWAIT_QUEUE) ContextList;
ContextList = Context;
} else {
//
// Break the link between the timer and the IRP
//
Context->Irp = NULL;
NpIrpWaitContext(Irp) = NULL;
}
//
// Remove cancelation. If its already running then let it complete the IRP.
//
if (IoSetCancelRoutine( Irp, NULL ) != NULL) {
Irp->IoStatus.Information = 0;
NpDeferredCompleteRequest (Irp, Completionstatus, DeferredList);
} else {
//
// Cancel is already running. Let it complete this IRP but let it know its orphaned.
//
NpIrpWaitContext(Irp) = NULL;
}
}
}
//
// Release the spinlock
//
KeReleaseSpinLock( &WaitQueue->SpinLock, OldIrql );
NpFreePool (NonPagedNameOfPipe.Buffer);
while (ContextList != NULL) {
Context = ContextList;
ContextList = (PWAIT_CONTEXT) Context->WaitQueue;
ObDereferenceObject (Context->FileObject);
NpFreePool( Context );
}
DebugTrace(-1, Dbg, "NpCancelWaiter -> VOID\n", 0);
//
// And now return to our caller
//
return STATUS_SUCCESS;
}
//
// Local support routine
//
VOID
NpTimerDispatch(
IN PKDPC Dpc,
IN PVOID Contxt,
IN PVOID SystemArgument1,
IN PVOID SystemArgument2
)
/*++
Routine Description:
This routine is called whenever a timer on a wait queue Irp goes off
Arguments:
Dpc - Ignored
Contxt - Supplies a pointer to the context whose timer went off
SystemArgument1 - Ignored
SystemArgument2 - Ignored
Return Value:
none.
--*/
{
PIRP Irp;
KIRQL OldIrql;
PLIST_ENTRY Links;
PWAIT_CONTEXT Context;
PWAIT_QUEUE WaitQueue;
UNREFERENCED_PARAMETER( Dpc );
UNREFERENCED_PARAMETER( SystemArgument1 );
UNREFERENCED_PARAMETER( SystemArgument2 );
Context = (PWAIT_CONTEXT)Contxt;
WaitQueue = Context->WaitQueue;
KeAcquireSpinLock( &WaitQueue->SpinLock, &OldIrql );
Irp = Context->Irp;
if (Irp != NULL) {
RemoveEntryList( &Irp->Tail.Overlay.ListEntry );
if (IoSetCancelRoutine (Irp, NULL) == NULL) {
//
// Cancel started running. Let it complete the IRP but show its orphaned
//
NpIrpWaitContext(Irp) = NULL;
Irp = NULL;
}
}
KeReleaseSpinLock( &WaitQueue->SpinLock, OldIrql );
if (Irp != NULL) {
NpCompleteRequest( Irp, STATUS_IO_TIMEOUT );
}
//
// Remove the file reference now we have finished with the wait queue.
//
ObDereferenceObject (Context->FileObject);
//
// Deallocate the context
//
NpFreePool (Context);
//
// And now return to our caller
//
return;
}
//
// Local Support routine
//
VOID
NpCancelWaitQueueIrp(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp
)
/*++
Routine Description:
This routine is called to cancel a wait queue irp
Arguments:
DeviceObject - Ignored
Irp - Supplies the Irp being cancelled. The Iosb.Status field in the irp
points to the wait queue
Return Value:
none.
--*/
{
PWAIT_QUEUE WaitQueue;
KIRQL OldIrql;
PLIST_ENTRY Links;
PWAIT_CONTEXT Context;
UNREFERENCED_PARAMETER( DeviceObject );
IoReleaseCancelSpinLock( Irp->CancelIrql );
//
// The status field is used to store a pointer to the wait queue
// containing this irp
//
WaitQueue = NpIrpWaitQueue(Irp);
//
// Get the spinlock proctecting the wait queue
//
KeAcquireSpinLock( &WaitQueue->SpinLock, &OldIrql );
Context = NpIrpWaitContext(Irp);
if (Context != NULL) {
RemoveEntryList (&Irp->Tail.Overlay.ListEntry);
if (!KeCancelTimer( &Context->Timer )) {
//
// Timer is already running. Break the link between the timer and the IRP as this thread is going to complete it.
//
Context->Irp = NULL;
Context = NULL;
}
}
KeReleaseSpinLock( &WaitQueue->SpinLock, OldIrql );
if (Context) {
ObDereferenceObject (Context->FileObject);
NpFreePool (Context);
}
Irp->IoStatus.Information = 0;
NpCompleteRequest( Irp, STATUS_CANCELLED );
//
// And return to our caller
//
return;
}
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