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193 lines
4.8 KiB
193 lines
4.8 KiB
/*++
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Copyright (c) 1989 Microsoft Corporation
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Module Name:
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writesup.c
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Abstract:
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This module implements the write support routine. This is a common
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write function that is called by write and mailslot write.
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Author:
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Manny Weiser (mannyw) 16-Jan-1991
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Revision History:
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--*/
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#include "mailslot.h"
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//
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// The debug trace level
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//
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#define Dbg (DEBUG_TRACE_WRITESUP)
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text( PAGE, MsWriteDataQueue )
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#endif
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NTSTATUS
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MsWriteDataQueue (
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IN PDATA_QUEUE WriteQueue,
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IN PUCHAR WriteBuffer,
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IN ULONG WriteLength
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)
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/*++
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Routine Description:
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This function writes data from the write buffer into read entries in
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the write queue. It will also dequeue entries in the queue as necessary.
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Arguments:
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WriteQueue - Provides the write queue to process.
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WriteBuffer - Provides the buffer from which to read the data.
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WriteLength - Provides the length, in bytes, of WriteBuffer.
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Return Value:
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STATUS_MORE_PROCESSING_REQUIRED if not all the data was written,
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other status codes as appropriate.
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--*/
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{
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NTSTATUS status;
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BOOLEAN result;
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PDATA_ENTRY dataEntry;
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PLIST_ENTRY listEntry;
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PFCB fcb;
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PUCHAR readBuffer;
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ULONG readLength;
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PIRP readIrp;
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NTSTATUS readStatus = STATUS_UNSUCCESSFUL;
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PWORK_CONTEXT workContext;
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PKTIMER timer;
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PAGED_CODE();
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DebugTrace(+1, Dbg, "MsWriteDataQueue\n", 0);
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DebugTrace( 0, Dbg, "WriteQueue = %08lx\n", (ULONG)WriteQueue);
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DebugTrace( 0, Dbg, "WriteBuffer = %08lx\n", (ULONG)WriteBuffer);
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DebugTrace( 0, Dbg, "WriteLength = %08lx\n", WriteLength);
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//
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// Now while the write queue has some read entries in it and
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// we have not successfully completed a read then we'll do the
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// following main loop.
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//
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status = STATUS_MORE_PROCESSING_REQUIRED;
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for (listEntry = MsGetNextDataQueueEntry( WriteQueue );
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(MsIsDataQueueReaders(WriteQueue) &&
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status == STATUS_MORE_PROCESSING_REQUIRED);
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listEntry = MsGetNextDataQueueEntry( WriteQueue )) {
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dataEntry = CONTAINING_RECORD( listEntry, DATA_ENTRY, ListEntry );
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readBuffer = dataEntry->DataPointer;
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readLength = dataEntry->DataSize;
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DebugTrace(0, Dbg, "Top of write loop...\n", 0);
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DebugTrace(0, Dbg, "ReadBuffer = %08lx\n", (ULONG)readBuffer);
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DebugTrace(0, Dbg, "ReadLength = %08lx\n", readLength);
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//
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// If the buffer for this read operation is large enough
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// copy the data.
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//
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if ( readLength >= WriteLength ) {
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//
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// Copy the data from the write buffer to the read buffer. This may take an exception
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// because its a raw user mode buffer
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//
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status = readStatus = STATUS_SUCCESS;
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try {
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RtlCopyMemory (readBuffer,
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WriteBuffer,
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WriteLength);
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} except (EXCEPTION_EXECUTE_HANDLER) {
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return GetExceptionCode ();
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}
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} else {
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//
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// This read buffer was overflowed.
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//
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WriteLength = 0;
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readStatus = STATUS_BUFFER_TOO_SMALL;
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}
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//
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// We are about to complete a read IRP, so dequeue it.
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//
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readIrp = MsRemoveDataQueueEntry( WriteQueue, dataEntry );
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if ( readIrp == NULL) {
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//
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// Cancel routine was already running for this IRP. Ignore it as it will be completed by
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// cancel code. Force the loop for the next read irp if there is one.
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//
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status = STATUS_MORE_PROCESSING_REQUIRED;
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continue;
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}
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//
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// Update the FCB last access time and complete the read request.
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//
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fcb = CONTAINING_RECORD( WriteQueue, FCB, DataQueue );
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if ( NT_SUCCESS( readStatus ) ) {
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KeQuerySystemTime( &fcb->Specific.Fcb.LastAccessTime );
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}
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readIrp->IoStatus.Information = WriteLength;
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MsCompleteRequest( readIrp, readStatus );
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}
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DebugTrace(0, Dbg, "Finished loop...\n", 0);
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//
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// At this point we've finished off all of the read entries in the
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// queue and we might not have written the write data. If that
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// is the case then we'll set our result to FALSE otherwise we're
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// done so we'll return TRUE.
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//
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if ( status == STATUS_MORE_PROCESSING_REQUIRED ) {
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ASSERT( !MsIsDataQueueReaders( WriteQueue ));
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}
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DebugTrace(-1, Dbg, "MsWriteDataQueue -> %08lx\n", status);
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return status;
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}
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