WindowsXP-SP1/base/fs/npfs/writesup.c
2020-09-30 16:53:49 +02:00

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/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
WriteSup.c
Abstract:
This module implements the Write support routine. This is a common
write function that is called by write, unbuffered write, and transceive.
Author:
Gary Kimura [GaryKi] 21-Sep-1990
Revision History:
--*/
#include "NpProcs.h"
//
// The debug trace level
//
#define Dbg (DEBUG_TRACE_WRITESUP)
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, NpWriteDataQueue)
#endif
NTSTATUS
NpWriteDataQueue (
IN PDATA_QUEUE WriteQueue,
IN READ_MODE ReadMode,
IN PUCHAR WriteBuffer,
IN ULONG WriteLength,
IN NAMED_PIPE_TYPE PipeType,
OUT PULONG WriteRemaining,
IN PCCB Ccb,
IN NAMED_PIPE_END NamedPipeEnd,
IN PETHREAD UserThread,
IN PLIST_ENTRY DeferredList
)
/*++
Routine Description:
This procedure writes data from the write buffer into read entries in
the write queue. It will also dequeue entries in the queue as necessary.
Arguments:
WriteQueue - Provides the write queue to process.
ReadMode - Supplies the read mode of read entries in the write queue.
WriteBuffer - Provides the buffer from which to read the data.
WriteLength - Provides the length, in bytes, of WriteBuffer.
PipeType - Indicates if type of pipe (i.e., message or byte stream).
WriteRemaining - Receives the number of bytes remaining to be transfered
that were not completed by this call. If the operation wrote
everything then is value is set to zero.
Ccb - Supplies the ccb for the operation
NamedPipeEnd - Supplies the end of the pipe doing the write
UserThread - Supplies the user thread
DeferredList - List of IRPs to be completed after we drop the locks
Return Value:
BOOLEAN - TRUE if the operation wrote everything and FALSE otherwise.
Note that a zero byte message that hasn't been written will return
a function result of FALSE and WriteRemaining of zero.
--*/
{
NTSTATUS Result;
BOOLEAN WriteZeroMessage;
PDATA_ENTRY DataEntry;
PUCHAR ReadBuffer;
ULONG ReadLength;
ULONG AmountToCopy;
NTSTATUS Status;
PSECURITY_CLIENT_CONTEXT SecurityContext;
BOOLEAN DoneSecurity=FALSE;
PIO_STACK_LOCATION IrpSp;
BOOLEAN FreeBuffer;
PIRP ReadIrp;
PAGED_CODE();
DebugTrace(+1, Dbg, "NpWriteDataQueue\n", 0);
DebugTrace( 0, Dbg, "WriteQueue = %08lx\n", WriteQueue);
DebugTrace( 0, Dbg, "WriteBuffer = %08lx\n", WriteBuffer);
DebugTrace( 0, Dbg, "WriteLength = %08lx\n", WriteLength);
DebugTrace( 0, Dbg, "PipeType = %08lx\n", PipeType);
DebugTrace( 0, Dbg, "Ccb = %08lx\n", Ccb);
DebugTrace( 0, Dbg, "NamedPipeEnd = %08lx\n", NamedPipeEnd);
DebugTrace( 0, Dbg, "UserThread = %08lx\n", UserThread);
//
// Determine if we are to write a zero byte message, and initialize
// WriteRemaining
//
*WriteRemaining = WriteLength;
if ((PipeType == FILE_PIPE_MESSAGE_TYPE) && (WriteLength == 0)) {
WriteZeroMessage = TRUE;
} else {
WriteZeroMessage = FALSE;
}
//
// Now while the write queue has some read entries in it and
// there is some remaining write data or this is a write zero message
// then we'll do the following main loop
//
for (DataEntry = NpGetNextRealDataQueueEntry( WriteQueue, DeferredList );
(NpIsDataQueueReaders(WriteQueue) &&
((*WriteRemaining > 0) || WriteZeroMessage));
DataEntry = NpGetNextRealDataQueueEntry( WriteQueue, DeferredList )) {
ReadLength = DataEntry->DataSize;
DebugTrace(0, Dbg, "Top of main loop...\n", 0);
DebugTrace(0, Dbg, "ReadBuffer = %08lx\n", ReadBuffer);
DebugTrace(0, Dbg, "ReadLength = %08lx\n", ReadLength);
DebugTrace(0, Dbg, "*WriteRemaining = %08lx\n", *WriteRemaining);
//
// Check if this is a ReadOverflow Operation and if so then also check
// that the read will succeed otherwise complete this read with
// buffer overflow and continue on.
//
IrpSp = IoGetCurrentIrpStackLocation( DataEntry->Irp );
if (IrpSp->MajorFunction == IRP_MJ_FILE_SYSTEM_CONTROL &&
IrpSp->Parameters.FileSystemControl.FsControlCode == FSCTL_PIPE_INTERNAL_READ_OVFLOW) {
if ((ReadLength < WriteLength) || WriteZeroMessage) {
ReadIrp = NpRemoveDataQueueEntry( WriteQueue, TRUE, DeferredList );
if (ReadIrp != NULL) {
NpDeferredCompleteRequest( ReadIrp, STATUS_BUFFER_OVERFLOW, DeferredList );
}
continue;
}
}
if (DataEntry->DataEntryType == Unbuffered) {
DataEntry->Irp->Overlay.AllocationSize.QuadPart = WriteQueue->BytesInQueue - WriteQueue->BytesInQueue;
}
//
// copy data from the write buffer at write offset to the
// read buffer at read offset by the mininum of write remaining
// or read remaining
//
AmountToCopy = (*WriteRemaining < ReadLength ? *WriteRemaining
: ReadLength);
if (DataEntry->DataEntryType != Unbuffered && AmountToCopy > 0) {
ReadBuffer = NpAllocatePagedPool ( AmountToCopy, 'RFpN' );
if (ReadBuffer == NULL) {
return STATUS_INSUFFICIENT_RESOURCES;
}
FreeBuffer = TRUE;
} else {
ReadBuffer = DataEntry->Irp->AssociatedIrp.SystemBuffer;
FreeBuffer = FALSE;
}
try {
RtlCopyMemory( ReadBuffer,
&WriteBuffer[ WriteLength - *WriteRemaining ],
AmountToCopy );
} except (EXCEPTION_EXECUTE_HANDLER) {
if (FreeBuffer) {
NpFreePool (ReadBuffer);
}
return GetExceptionCode ();
}
//
// Done update the security in the CCB multiple times. It won't change.
//
if (DoneSecurity == FALSE) {
DoneSecurity = TRUE;
//
// Now update the security fields in the nonpaged ccb
//
Status = NpGetClientSecurityContext (NamedPipeEnd,
Ccb,
UserThread,
&SecurityContext);
if (!NT_SUCCESS(Status)) {
if (FreeBuffer) {
NpFreePool (ReadBuffer);
}
return Status;
}
if (SecurityContext != NULL) {
NpFreeClientSecurityContext (Ccb->SecurityClientContext);
Ccb->SecurityClientContext = SecurityContext;
}
}
//
// Now we've done with the read entry so remove it from the
// write queue, get its irp, and fill in the information field
// to be the bytes that we've transferred into the read buffer.
//
ReadIrp = NpRemoveDataQueueEntry( WriteQueue, TRUE, DeferredList );
if (ReadIrp == NULL) {
if (FreeBuffer) {
NpFreePool (ReadBuffer);
}
continue;
}
//
// Update the Write remaining counts
//
*WriteRemaining -= AmountToCopy;
ReadIrp->IoStatus.Information = AmountToCopy;
if (FreeBuffer) {
ReadIrp->AssociatedIrp.SystemBuffer = ReadBuffer;
ReadIrp->Flags |= IRP_BUFFERED_IO | IRP_DEALLOCATE_BUFFER | IRP_INPUT_OPERATION;
}
if (*WriteRemaining == 0) {
DebugTrace(0, Dbg, "Finished up the write remaining\n", 0);
//**** ASSERT( ReadIrp->IoStatus.Information != 0 );
NpDeferredCompleteRequest( ReadIrp, STATUS_SUCCESS, DeferredList );
WriteZeroMessage = FALSE;
} else {
//
// There is still some space in the write buffer to be
// written out, but before we can handle that (in the
// following if statement) we need to finish the read.
// If the read is message mode then we've overflowed the
// buffer otherwise we completed successfully
//
if (ReadMode == FILE_PIPE_MESSAGE_MODE) {
DebugTrace(0, Dbg, "Read buffer Overflow\n", 0);
NpDeferredCompleteRequest( ReadIrp, STATUS_BUFFER_OVERFLOW, DeferredList );
} else {
DebugTrace(0, Dbg, "Read buffer byte stream done\n", 0);
//**** ASSERT( ReadIrp->IoStatus.Information != 0 );
NpDeferredCompleteRequest( ReadIrp, STATUS_SUCCESS, DeferredList );
}
}
}
DebugTrace(0, Dbg, "Finished loop...\n", 0);
DebugTrace(0, Dbg, "*WriteRemaining = %08lx\n", *WriteRemaining);
DebugTrace(0, Dbg, "WriteZeroMessage = %08lx\n", WriteZeroMessage);
//
// At this point we've finished off all of the read entries in the
// queue and we might still have something left to write. If that
// is the case then we'll set our result to FALSE otherwise we're
// done so we'll return TRUE.
//
if ((*WriteRemaining > 0) || (WriteZeroMessage)) {
ASSERT( !NpIsDataQueueReaders( WriteQueue ));
Result = STATUS_MORE_PROCESSING_REQUIRED;
} else {
Result = STATUS_SUCCESS;
}
DebugTrace(-1, Dbg, "NpWriteDataQueue -> %08lx\n", Result);
return Result;
}