reactos/drivers/dd/null/null.c

   1 /* $Id: null.c,v 1.12 2003/11/17 02:12:49 hyperion Exp $
   2  *
   3  * COPYRIGHT:        See COPYING in the top level directory
   4  * PROJECT:          ReactOS kernel
   5  * FILE:             services/null/null.c
   6  * PURPOSE:          NULL device driver
   7  * PROGRAMMER:       David Welch (welch@mcmail.com)
   8  * UPDATE HISTORY:
   9  *              13/08/1998: Created
  10  *              29/04/2002: Fixed bugs, added zero-stream device
  11  */
  12
  13 /* INCLUDES */
  14 #include <ddk/ntddk.h>
  15 #include <rosrtl/string.h>
  16 #include "null.h"
  17
  18 /* OBJECTS */
  19 static const NULL_EXTENSION nxNull = NullBitBucket;
  20 static const NULL_EXTENSION nxZero = NullZeroStream;
  21
  22 /* FUNCTIONS */
  23 NTSTATUS STDCALL
  24 NullDispatch(PDEVICE_OBJECT DeviceObject, PIRP Irp)
  25 {
  26  PIO_STACK_LOCATION piosStack = IoGetCurrentIrpStackLocation(Irp);
  27  NTSTATUS nErrCode;
  28
  29  nErrCode = STATUS_SUCCESS;
  30
  31  switch(piosStack->MajorFunction)
  32  {
  33   /* opening and closing handles to the device */
  34   case IRP_MJ_CREATE:
  35   case IRP_MJ_CLOSE:
  36   {
  37    break;
  38   }
  39
  40   /* write data */
  41   case IRP_MJ_WRITE:
  42   {
  43    switch(NULL_DEVICE_TYPE(DeviceObject))
  44    {
  45     case NullBitBucket:
  46      Irp->IoStatus.Information = piosStack->Parameters.Write.Length;
  47      break;
  48
  49     case NullZeroStream:
  50     default:
  51      Irp->IoStatus.Information = 0;
  52      nErrCode = STATUS_NOT_IMPLEMENTED;
  53    }
  54
  55    break;
  56   }
  57
  58   /* read data */
  59   case IRP_MJ_READ:
  60   {
  61    switch(NULL_DEVICE_TYPE(DeviceObject))
  62    {
  63     case NullBitBucket:
  64      Irp->IoStatus.Information = 0;
  65      nErrCode = STATUS_END_OF_FILE;
  66      break;
  67
  68     case NullZeroStream:
  69      RtlZeroMemory(Irp->AssociatedIrp.SystemBuffer, piosStack->Parameters.Read.Length);
  70      Irp->IoStatus.Information = piosStack->Parameters.Read.Length;
  71      break;
  72
  73     default:
  74      Irp->IoStatus.Information = 0;
  75      nErrCode = STATUS_NOT_IMPLEMENTED;
  76    }
  77
  78    break;
  79   }
  80
  81   /* unsupported operations */
  82   default:
  83   {
  84    nErrCode = STATUS_NOT_IMPLEMENTED;
  85   }
  86  }
  87
  88  Irp->IoStatus.Status = nErrCode;
  89  IoCompleteRequest(Irp, IO_NO_INCREMENT);
  90
  91  return (nErrCode);
  92 }
  93
  94 NTSTATUS STDCALL
  95 NullUnload(PDRIVER_OBJECT DriverObject)
  96 {
  97  return(STATUS_SUCCESS);
  98 }
  99
 100 NTSTATUS STDCALL
 101 DriverEntry(PDRIVER_OBJECT DriverObject, PUNICODE_STRING RegistryPath)
 102 {
 103  PDEVICE_OBJECT pdoNullDevice;
 104  PDEVICE_OBJECT pdoZeroDevice;
 105  UNICODE_STRING wstrDeviceName;
 106  NTSTATUS nErrCode;
 107
 108  /* register driver routines */
 109  DriverObject->MajorFunction[IRP_MJ_CLOSE] = (PDRIVER_DISPATCH)NullDispatch;
 110  DriverObject->MajorFunction[IRP_MJ_CREATE] = (PDRIVER_DISPATCH)NullDispatch;
 111  DriverObject->MajorFunction[IRP_MJ_WRITE] = (PDRIVER_DISPATCH)NullDispatch;
 112  DriverObject->MajorFunction[IRP_MJ_READ] = (PDRIVER_DISPATCH)NullDispatch;
 113  /* DriverObject->MajorFunction[IRP_MJ_QUERY_INFORMATION] = (PDRIVER_DISPATCH)NullDispatch; */
 114  DriverObject->DriverUnload = (PDRIVER_UNLOAD)NullUnload;
 115
 116  /* create null device */
 117  RtlRosInitUnicodeStringFromLiteral(&wstrDeviceName, L"\\Device\\Null");
 118
 119  nErrCode = IoCreateDevice
 120  (
 121   DriverObject,
 122   sizeof(NULL_EXTENSION),
 123   &wstrDeviceName,
 124   FILE_DEVICE_NULL,
 125   0,
 126   FALSE,
 127   &pdoNullDevice
 128  );
 129
 130  /* failure */
 131  if(!NT_SUCCESS(nErrCode))
 132  {
 133   return (nErrCode);
 134  }
 135
 136  pdoNullDevice->DeviceExtension = (PVOID)&nxNull;
 137
 138  /* create zero device */
 139  RtlRosInitUnicodeStringFromLiteral(&wstrDeviceName, L"\\Device\\Zero");
 140
 141  nErrCode = IoCreateDevice
 142  (
 143   DriverObject,
 144   sizeof(NULL_EXTENSION),
 145   &wstrDeviceName,
 146   FILE_DEVICE_NULL,
 147   FILE_READ_ONLY_DEVICE, /* zero device is read-only */
 148   FALSE,
 149   &pdoZeroDevice
 150  );
 151
 152  /* failure */
 153  if(!NT_SUCCESS(nErrCode))
 154  {
 155   IoDeleteDevice(pdoNullDevice);
 156   return (nErrCode);
 157  }
 158
 159  pdoZeroDevice->DeviceExtension = (PVOID)&nxZero;
 160  pdoZeroDevice->Flags |= DO_BUFFERED_IO;
 161
 162  return (nErrCode);
 163 }
 164
 165 /* EOF */