src/add-ons/kernel/drivers/common/null.c

   1 /*
   2  * Copyright 2002-2006, Haiku, Inc. All Rights Reserved.
   3  * Distributed under the terms of the MIT License.
   4  *
   5  * Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
   6  * Distributed under the terms of the NewOS License.
   7  */
   8
   9
  10 #include <Drivers.h>
  11 #include <string.h>
  12
  13
  14 #define DEVICE_NAME "null"
  15
  16 int32 api_version = B_CUR_DRIVER_API_VERSION;
  17
  18
  19 static status_t
  20 null_open(const char *name, uint32 flags, void **cookie)
  21 {
  22         *cookie = NULL;
  23         return B_OK;
  24 }
  25
  26
  27 static status_t
  28 null_close(void *cookie)
  29 {
  30         return B_OK;
  31 }
  32
  33
  34 static status_t
  35 null_freecookie(void *cookie)
  36 {
  37         return B_OK;
  38 }
  39
  40
  41 static status_t
  42 null_ioctl(void *cookie, uint32 op, void *buffer, size_t length)
  43 {
  44         return EPERM;
  45 }
  46
  47
  48 static status_t
  49 null_read(void *cookie, off_t pos, void *buffer, size_t *_length)
  50 {
  51         *_length = 0;
  52         return B_OK;
  53 }
  54
  55
  56 static status_t
  57 null_write(void *cookie, off_t pos, const void *buffer, size_t *_length)
  58 {
  59         return B_OK;
  60 }
  61
  62
  63 //      #pragma mark -
  64
  65
  66 status_t
  67 init_hardware()
  68 {
  69         return B_OK;
  70 }
  71
  72
  73 const char **
  74 publish_devices(void)
  75 {
  76         static const char *devices[] = {
  77                 DEVICE_NAME,
  78                 NULL
  79         };
  80
  81         return devices;
  82 }
  83
  84
  85 device_hooks *
  86 find_device(const char *name)
  87 {
  88         static device_hooks hooks = {
  89                 &null_open,
  90                 &null_close,
  91                 &null_freecookie,
  92                 &null_ioctl,
  93                 &null_read,
  94                 &null_write,
  95                 /* Leave select/deselect/readv/writev undefined. The kernel will
  96                  * use its own default implementation. The basic hooks above this
  97                  * line MUST be defined, however. */
  98                 NULL,
  99                 NULL,
 100                 NULL,
 101                 NULL
 102         };
 103
 104         if (!strcmp(name, DEVICE_NAME))
 105                 return &hooks;
 106
 107         return NULL;
 108 }
 109
 110
 111 status_t
 112 init_driver(void)
 113 {
 114         return B_OK;
 115 }
 116
 117
 118 void
 119 uninit_driver(void)
 120 {
 121 }
 122