fileinfo.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:

    FileInfo.c

Abstract:

    This module implements the File Information routines for Raw called by
    the dispatch driver.

--*/

#include "RawProcs.h"

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, RawQueryInformation)
#pragma alloc_text(PAGE, RawSetInformation)
#endif

NTSTATUS
RawQueryInformation (
    IN PVCB Vcb,
    IN PIRP Irp,
    PIO_STACK_LOCATION IrpSp
    )

/*++

Routine Description:

    This is the routine for querying file information, though only
    query current file position is supported.

Arguments:

    Vcb - Supplies the volume being queried.

    Irp - Supplies the Irp being processed.

    IrpSp - Supplies parameters describing the query


Return Value:

    NTSTATUS - The return status for the operation

--*/

{
    NTSTATUS Status;

    PULONG Length;
    FILE_INFORMATION_CLASS FileInformationClass;
    PFILE_POSITION_INFORMATION Buffer;

    PAGED_CODE();

    //
    //  Reference our input parameters to make things easier
    //

    Length = &IrpSp->Parameters.QueryFile.Length;
    FileInformationClass = IrpSp->Parameters.QueryFile.FileInformationClass;
    Buffer = Irp->AssociatedIrp.SystemBuffer;

    //
    //  The only request that is valid for raw is to query file position.
    //

    if ( FileInformationClass == FilePositionInformation ) {

        //
        //  Make sure the buffer is large enough
        //

        if (*Length < sizeof(FILE_POSITION_INFORMATION)) {

            Irp->IoStatus.Information = 0;

            Status = STATUS_BUFFER_OVERFLOW;

        } else {

            //
            //  Get the current position found in the file object.
            //

            Buffer->CurrentByteOffset = IrpSp->FileObject->CurrentByteOffset;

            //
            //  Update the length, irp info, and status output variables
            //

            *Length -= sizeof( FILE_POSITION_INFORMATION );

            Irp->IoStatus.Information = sizeof( FILE_POSITION_INFORMATION );

            Status = STATUS_SUCCESS;
        }

    } else {

        Status = STATUS_INVALID_DEVICE_REQUEST;
    }

    RawCompleteRequest( Irp, Status );

    UNREFERENCED_PARAMETER( Vcb );

    return Status;
}

NTSTATUS
RawSetInformation (
    IN PVCB Vcb,
    IN PIRP Irp,
    PIO_STACK_LOCATION IrpSp
    )

/*++

Routine Description:

    This is the routine for setting file information, though only
    setting current file position is supported.

Arguments:

    Vcb - Supplies the volume being queried.

    Irp - Supplies the Irp being processed.

    IrpSp - Supplies parameters describing the set


Return Value:

    NTSTATUS - The return status for the operation

--*/

{
    NTSTATUS Status;

    FILE_INFORMATION_CLASS FileInformationClass;
    PFILE_POSITION_INFORMATION Buffer;
    PFILE_OBJECT FileObject;

    PAGED_CODE();

    //
    //  Reference our input parameters to make things easier
    //

    FileInformationClass = IrpSp->Parameters.SetFile.FileInformationClass;
    Buffer = (PFILE_POSITION_INFORMATION)Irp->AssociatedIrp.SystemBuffer;
    FileObject= IrpSp->FileObject;

    //
    //  The only request that is valid for raw is to set file position.
    //

    if ( FileInformationClass == FilePositionInformation ) {

        //
        //  Check that the new position we're supplied is aligned properly
        //  for the device.
        //

        PDEVICE_OBJECT DeviceObject;

        DeviceObject = IoGetRelatedDeviceObject( IrpSp->FileObject );

        if ((Buffer->CurrentByteOffset.LowPart & DeviceObject->AlignmentRequirement) != 0) {

            Status = STATUS_INVALID_PARAMETER;

        } else {

            //
            //  The input parameter is fine so set the current byte offset.
            //

            FileObject->CurrentByteOffset = Buffer->CurrentByteOffset;

            Status = STATUS_SUCCESS;
        }

    } else {

        Status = STATUS_INVALID_DEVICE_REQUEST;
    }

    RawCompleteRequest( Irp, Status );

    UNREFERENCED_PARAMETER( Vcb );

    return Status;
}