rawdisp.c

Windows内核级文件系统访问操作驱动程序

/*++

Copyright (c) Microsoft Corporation. All rights reserved. 

You may only use this code if you agree to the terms of the Windows Research Kernel Source Code License agreement (see License.txt).
If you do not agree to the terms, do not use the code.


Module Name:

    RawDisp.c

Abstract:

    This module is the main entry point for all major function codes.
    It is responsible for dispatching the request to the appropriate
    routine.

--*/

#include "RawProcs.h"

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, RawDispatch)
#endif


NTSTATUS
RawDispatch (
    IN PVOLUME_DEVICE_OBJECT VolumeDeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    Dispatch the request to the appropriate function.  It is the worker
    function's responsibility to appropriately complete the IRP.

Arguments:

    VolumeDeviceObject - Supplies the volume device object to use.

    Irp - Supplies the Irp being processed

Return Value:

    NTSTATUS - The status for the IRP

--*/

{
    NTSTATUS Status;
    PIO_STACK_LOCATION IrpSp;
    PVCB Vcb;

    PAGED_CODE();

    //
    //  Get a pointer to the current stack location.  This location contains
    //  the function codes and parameters for this particular request.
    //

    IrpSp = IoGetCurrentIrpStackLocation( Irp );

    //
    //  Check for operations associated with our FileSystemDeviceObjects
    //  as opposed to our VolumeDeviceObjects.  Only mount is allowed to
    //  continue through the normal dispatch in this case.
    //

    if ((((PDEVICE_OBJECT)VolumeDeviceObject)->Size == sizeof(DEVICE_OBJECT)) &&
        !((IrpSp->MajorFunction == IRP_MJ_FILE_SYSTEM_CONTROL) &&
          (IrpSp->MinorFunction == IRP_MN_MOUNT_VOLUME))) {

        if ((IrpSp->MajorFunction == IRP_MJ_CREATE) ||
            (IrpSp->MajorFunction == IRP_MJ_CLEANUP) ||
            (IrpSp->MajorFunction == IRP_MJ_CLOSE)) {

            Status = STATUS_SUCCESS;

        } else {

            Status = STATUS_INVALID_DEVICE_REQUEST;
        }

        RawCompleteRequest( Irp, Status );

        return Status;
    }

    FsRtlEnterFileSystem();

    //
    //  Get a pointer to the Vcb.  Note that is we are mount a volume this
    //  pointer will not have meaning, but that is OK since we will not
    //  use it in that case.
    //

    Vcb = &VolumeDeviceObject->Vcb;

    //
    //  Case on the function that is being performed by the requestor.  We
    //  should only see expected requests since we filled the dispatch table
    //  by hand.
    //

    try {

        switch ( IrpSp->MajorFunction ) {

            case IRP_MJ_CLEANUP:

                Status = RawCleanup( Vcb, Irp, IrpSp );
                break;

            case IRP_MJ_CLOSE:

                Status = RawClose( Vcb, Irp, IrpSp );
                break;

            case IRP_MJ_CREATE:

                Status = RawCreate( Vcb, Irp, IrpSp );
                break;

            case IRP_MJ_FILE_SYSTEM_CONTROL:

                Status = RawFileSystemControl( Vcb, Irp, IrpSp );
                break;

            case IRP_MJ_PNP: 

                if(IrpSp->MinorFunction == IRP_MN_QUERY_REMOVE_DEVICE) {
                    Status = STATUS_DEVICE_BUSY;
                    RawCompleteRequest(Irp, Status);
                    break;
                } 

            case IRP_MJ_READ:
            case IRP_MJ_WRITE:
            case IRP_MJ_DEVICE_CONTROL:

                Status = RawReadWriteDeviceControl( Vcb, Irp, IrpSp );
                break;

            case IRP_MJ_QUERY_INFORMATION:

                Status = RawQueryInformation( Vcb, Irp, IrpSp );
                break;

            case IRP_MJ_SET_INFORMATION:

                Status = RawSetInformation( Vcb, Irp, IrpSp );
                break;

            case IRP_MJ_QUERY_VOLUME_INFORMATION:

                Status = RawQueryVolumeInformation( Vcb, Irp, IrpSp );
                break;

            default:

                //
                //  We should never get a request we don't expect.
                //

                KdPrint(("Raw: Illegal Irp major function code 0x%x.\n", IrpSp->MajorFunction));
                KeBugCheckEx( FILE_SYSTEM, 0, 0, 0, 0 );
        }

    } except( FsRtlIsNtstatusExpected(GetExceptionCode()) ?
              EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH ) {

        //
        //  No routine we call should ever generate an exception
        //

        Status = GetExceptionCode();

        KdPrint(("Raw: Unexpected exception %X.\n", Status));
    }

    //
    //  And return to our caller
    //

    FsRtlExitFileSystem();

    return Status;
}

//
//  Completion routine for read, write, and device control to deal with
//  verify issues.  Implemented in RawDisp.c
//

NTSTATUS
RawCompletionRoutine(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp,
    IN PVOID Context
    )

{
    PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation( Irp );

    //
    //  Simply update the file pointer context in the file object if we
    //  were successful and this was a synrchonous read or write.
    //

    if (((IrpSp->MajorFunction == IRP_MJ_READ) ||
         (IrpSp->MajorFunction == IRP_MJ_WRITE)) &&
        (IrpSp->FileObject != NULL) &&
        FlagOn(IrpSp->FileObject->Flags, FO_SYNCHRONOUS_IO) &&
        NT_SUCCESS(Irp->IoStatus.Status)) {

        IrpSp->FileObject->CurrentByteOffset.QuadPart =
            IrpSp->FileObject->CurrentByteOffset.QuadPart +
            Irp->IoStatus.Information;
    }

    //
    //  If IoCallDriver returned PENDING, mark our stack location
    //  with pending.
    //

    if ( Irp->PendingReturned ) {

        IoMarkIrpPending( Irp );
    }

    UNREFERENCED_PARAMETER( DeviceObject );
    UNREFERENCED_PARAMETER( Context );

    return STATUS_SUCCESS;
}