null.c File Reference

#include <wdm.h>

Include dependency graph for null.c:

Go to the source code of this file.

Functions
NTSTATUS NTAPI	NullQueryFileInformation (OUT PVOID Buffer, IN PULONG Length, IN FILE_INFORMATION_CLASS InformationClass)
BOOLEAN NTAPI	NullRead (IN PFILE_OBJECT FileObject, IN PLARGE_INTEGER FileOffset, IN ULONG Length, IN BOOLEAN Wait, IN ULONG LockKey, OUT PVOID Buffer, OUT PIO_STATUS_BLOCK IoStatus, IN PDEVICE_OBJECT DeviceObject)
BOOLEAN NTAPI	NullWrite (IN PFILE_OBJECT FileObject, IN PLARGE_INTEGER FileOffset, IN ULONG Length, IN BOOLEAN Wait, IN ULONG LockKey, IN PVOID Buffer, OUT PIO_STATUS_BLOCK IoStatus, IN PDEVICE_OBJECT DeviceObject)
NTSTATUS NTAPI	NullDispatch (IN PDEVICE_OBJECT DeviceObject, IN PIRP Irp)
VOID NTAPI	NullUnload (IN PDRIVER_OBJECT DriverObject)
NTSTATUS NTAPI	DriverEntry (IN PDRIVER_OBJECT DriverObject, IN PUNICODE_STRING RegistryPath)

Variables
FAST_IO_DISPATCH	FastIoDispatch

Function Documentation

DriverEntry()

NTSTATUS NTAPI DriverEntry	(	IN PDRIVER_OBJECT	DriverObject,
		IN PUNICODE_STRING	RegistryPath
	)

Definition at line 170 of file null.c.

{
    NTSTATUS Status;
    PDEVICE_OBJECT DeviceObject;
    UNICODE_STRING DeviceName = RTL_CONSTANT_STRING(L"\\Device\\Null");
 
    PAGED_CODE();
 
    UNREFERENCED_PARAMETER(RegistryPath);
 
    /* Page the driver */
    MmPageEntireDriver(DriverEntry);
 
    /* Create the Null device */
    Status = IoCreateDevice(DriverObject,
                            0,
                            &DeviceName,
                            FILE_DEVICE_NULL,
                            FILE_DEVICE_SECURE_OPEN,
                            FALSE,
                            &DeviceObject);
    if (!NT_SUCCESS(Status))
        return Status;
 
    /* Register driver routines */
    DriverObject->MajorFunction[IRP_MJ_CLOSE] = NullDispatch;
    DriverObject->MajorFunction[IRP_MJ_CREATE] = NullDispatch;
    DriverObject->MajorFunction[IRP_MJ_WRITE] = NullDispatch;
    DriverObject->MajorFunction[IRP_MJ_READ] = NullDispatch;
    DriverObject->MajorFunction[IRP_MJ_LOCK_CONTROL] = NullDispatch;
    DriverObject->MajorFunction[IRP_MJ_QUERY_INFORMATION] = NullDispatch;
    DriverObject->DriverUnload = NullUnload;
 
    /* Initialize the fast I/O dispatch table */
    RtlZeroMemory(&FastIoDispatch, sizeof(FastIoDispatch));
    FastIoDispatch.SizeOfFastIoDispatch = sizeof(FastIoDispatch);
 
    /* Setup our pointers */
    FastIoDispatch.FastIoRead = NullRead;
    FastIoDispatch.FastIoWrite = NullWrite;
    DriverObject->FastIoDispatch = &FastIoDispatch;
 
    /* Return success */
    return STATUS_SUCCESS;
}

NullDispatch()

NTSTATUS NTAPI NullDispatch	(	IN PDEVICE_OBJECT	DeviceObject,
		IN PIRP	Irp
	)

Definition at line 85 of file null.c.

{
    NTSTATUS Status;
    PIO_STACK_LOCATION IoStack = IoGetCurrentIrpStackLocation(Irp);
    PFILE_OBJECT FileObject;
    ULONG Length;
 
    PAGED_CODE();
 
    /* Get the file object and check what kind of request this is */
    FileObject = IoStack->FileObject;
    switch (IoStack->MajorFunction)
    {
        case IRP_MJ_CREATE:
        case IRP_MJ_CLOSE:
 
            /* Check if this is synch I/O */
            if (FileObject->Flags & FO_SYNCHRONOUS_IO)
            {
                /* Set distinguished value for Cc */
                FileObject->PrivateCacheMap = (PVOID)1;
            }
 
            /* Complete successfully */
            Irp->IoStatus.Status = STATUS_SUCCESS;
            Irp->IoStatus.Information = 0;
            break;
 
         case IRP_MJ_READ:
 
            /* Return as if we read the entire file */
            Irp->IoStatus.Status = STATUS_END_OF_FILE;
            Irp->IoStatus.Information = 0;
            break;
 
        case IRP_MJ_WRITE:
 
            /* Return as if we wrote the entire request */
            Irp->IoStatus.Status = STATUS_SUCCESS;
            Irp->IoStatus.Information = IoStack->Parameters.Write.Length;
            break;
 
        case IRP_MJ_LOCK_CONTROL:
 
            /* Dummy */
            Irp->IoStatus.Status = STATUS_SUCCESS;
            Irp->IoStatus.Information = 0;
            break;
 
        case IRP_MJ_QUERY_INFORMATION:
 
            /* Get the length inputted and do the request */
            Length = IoStack->Parameters.QueryFile.Length;
            Irp->IoStatus.Status = NullQueryFileInformation(Irp->AssociatedIrp.
                                                            SystemBuffer,
                                                            &Length,
                                                            IoStack->
                                                            Parameters.
                                                            QueryFile.
                                                            FileInformationClass);
 
            /* Return the actual length */
            Irp->IoStatus.Information = Length;
            break;
    }
 
    /* Complete the request */
    Status = Irp->IoStatus.Status;
    IoCompleteRequest(Irp, IO_NO_INCREMENT);
    return Status;
}

Referenced by DriverEntry().

NullQueryFileInformation()

NTSTATUS NTAPI NullQueryFileInformation	(	OUT PVOID	Buffer,
		IN PULONG	Length,
		IN FILE_INFORMATION_CLASS	InformationClass
	)

Definition at line 21 of file null.c.

{
    PFILE_STANDARD_INFORMATION StandardInfo = Buffer;
 
    PAGED_CODE();
 
    /* We only support one class */
    if (InformationClass != FileStandardInformation)
    {
        /* Fail */
        return STATUS_INVALID_INFO_CLASS;
    }
 
    /* Fill out the information */
    RtlZeroMemory(StandardInfo, sizeof(FILE_STANDARD_INFORMATION));
    StandardInfo->NumberOfLinks = 1;
 
    /* Return the length and success */
    *Length = sizeof(FILE_STANDARD_INFORMATION);
    return STATUS_SUCCESS;
}

Referenced by NullDispatch().

NullRead()

BOOLEAN NTAPI NullRead	(	IN PFILE_OBJECT	FileObject,
		IN PLARGE_INTEGER	FileOffset,
		IN ULONG	Length,
		IN BOOLEAN	Wait,
		IN ULONG	LockKey,
		OUT PVOID	Buffer,
		OUT PIO_STATUS_BLOCK	IoStatus,
		IN PDEVICE_OBJECT	DeviceObject
	)

Definition at line 47 of file null.c.

{
    PAGED_CODE();
 
    /* Complete successfully */
    IoStatus->Status = STATUS_END_OF_FILE;
    IoStatus->Information = 0;
    return TRUE;
}

Referenced by DriverEntry().

NullUnload()

VOID NTAPI NullUnload

(

IN PDRIVER_OBJECT

DriverObject

)

Definition at line 160 of file null.c.

{
    PDEVICE_OBJECT DeviceObject = DriverObject->DeviceObject;
 
    /* Delete the Null device */
    IoDeleteDevice(DeviceObject);
}

Referenced by DriverEntry().

NullWrite()

BOOLEAN NTAPI NullWrite	(	IN PFILE_OBJECT	FileObject,
		IN PLARGE_INTEGER	FileOffset,
		IN ULONG	Length,
		IN BOOLEAN	Wait,
		IN ULONG	LockKey,
		IN PVOID	Buffer,
		OUT PIO_STATUS_BLOCK	IoStatus,
		IN PDEVICE_OBJECT	DeviceObject
	)

Definition at line 66 of file null.c.

{
    PAGED_CODE();
 
    /* Complete successfully */
    IoStatus->Status = STATUS_SUCCESS;
    IoStatus->Information = Length;
    return TRUE;
}

Referenced by DriverEntry().

Variable Documentation

FastIoDispatch

FAST_IO_DISPATCH FastIoDispatch

Definition at line 15 of file null.c.

Referenced by DriverEntry(), FltpFastIoCheckIfPossible(), FltpFastIoDeviceControl(), FltpFastIoLock(), FltpFastIoMdlRead(), FltpFastIoMdlReadComplete(), FltpFastIoMdlReadCompleteCompressed(), FltpFastIoMdlWriteComplete(), FltpFastIoMdlWriteCompleteCompressed(), FltpFastIoPrepareMdlWrite(), FltpFastIoQueryBasicInfo(), FltpFastIoQueryNetworkOpenInfo(), FltpFastIoQueryOpen(), FltpFastIoQueryStandardInfo(), FltpFastIoRead(), FltpFastIoReadCompressed(), FltpFastIoUnlockAll(), FltpFastIoUnlockAllByKey(), FltpFastIoUnlockSingle(), FltpFastIoWrite(), FltpFastIoWriteCompressed(), FsRtlCopyRead2(), FsRtlCopyWrite2(), IopDeviceFsIoControl(), KsQueryInformationFile(), NtLockFile(), NtQueryInformationFile(), NtReadFile(), NtUnlockFile(), NtWriteFile(), and SetupDispatchAndCallbacksTables().