reactos/drivers/dd/null/null.c

   1 /*
   2  * COPYRIGHT:        See COPYING in the top level directory
   3  * PROJECT:          ReactOS kernel
   4  * FILE:             services/null/null.c
   5  * PURPOSE:          NULL device driver
   6  * PROGRAMMER:       David Welch (welch@mcmail.com)
   7  * UPDATE HISTORY:
   8  *              13/08/98: Created
   9  */
  10
  11 /* INCLUDES ****************************************************************/
  12
  13 #include <ddk/ntddk.h>
  14
  15 /* FUNCTIONS **************************************************************/
  16
  17 NTSTATUS NullWrite(PIRP Irp, PIO_STACK_LOCATION stk)
  18 {
  19    Irp->IoStatus.Information = stk->Parameters.Write.Length;
  20    return(STATUS_SUCCESS);
  21 }
  22
  23 NTSTATUS NullRead(PIRP Irp, PIO_STACK_LOCATION stk)
  24 {
  25    Irp->IoStatus.Information = 0;
  26    return(STATUS_END_OF_FILE);
  27 }
  28
  29 NTSTATUS NullDispatch(PDEVICE_OBJECT DeviceObject, PIRP Irp)
  30 /*
  31  * FUNCTION: Handles user mode requests
  32  * ARGUMENTS:
  33  *           DeviceObject = Device for request
  34  *           Irp = I/O request packet describing request
  35  * RETURNS: Success or failure
  36  */
  37 {
  38    PIO_STACK_LOCATION Stack = IoGetCurrentIrpStackLocation(Irp);
  39    NTSTATUS status;
  40
  41    switch (Stack->MajorFunction)
  42      {
  43       case IRP_MJ_CREATE:
  44       case IRP_MJ_CLOSE:
  45         status = STATUS_SUCCESS;
  46         break;
  47
  48       case IRP_MJ_WRITE:
  49         status = NullWrite(Irp,Stack);
  50         break;
  51
  52       case IRP_MJ_READ:
  53         status = NullRead(Irp,Stack);
  54         break;
  55
  56       default:
  57         status = STATUS_NOT_IMPLEMENTED;
  58      }
  59
  60    Irp->IoStatus.Status = status;
  61    IoCompleteRequest(Irp,IO_NO_INCREMENT);
  62    return(status);
  63 }
  64
  65 NTSTATUS NullUnload(PDRIVER_OBJECT DriverObject)
  66 {
  67    return(STATUS_SUCCESS);
  68 }
  69
  70 NTSTATUS DriverEntry(PDRIVER_OBJECT DriverObject, PUNICODE_STRING RegistryPath)
  71 /*
  72  * FUNCTION: Called by the system to initalize the driver
  73  * ARGUMENTS:
  74  *           DriverObject = object describing this driver
  75  *           RegistryPath = path to our configuration entries
  76  * RETURNS: Success or failure
  77  */
  78 {
  79    PDEVICE_OBJECT DeviceObject;
  80    NTSTATUS ret;
  81    ANSI_STRING ansi_device_name;
  82    UNICODE_STRING device_name;
  83
  84    DbgPrint("Null Device Driver 0.0.1\n");
  85
  86    RtlInitAnsiString(&ansi_device_name,"\\Device\\NUL");
  87    RtlAnsiStringToUnicodeString(&device_name,&ansi_device_name,TRUE);
  88    ret = IoCreateDevice(DriverObject,0,&device_name,
  89                         FILE_DEVICE_NULL,0,FALSE,&DeviceObject);
  90    if (ret!=STATUS_SUCCESS)
  91      {
  92         return(ret);
  93      }
  94
  95    DeviceObject->Flags=0;
  96    DriverObject->MajorFunction[IRP_MJ_CLOSE] = NullDispatch;
  97    DriverObject->MajorFunction[IRP_MJ_CREATE] = NullDispatch;
  98    DriverObject->MajorFunction[IRP_MJ_WRITE] = NullDispatch;
  99    DriverObject->MajorFunction[IRP_MJ_READ] = NullDispatch;
 100    DriverObject->DriverUnload = NullUnload;
 101
 102    return(STATUS_SUCCESS);
 103 }
 104