arch/um/drivers/null.c

   1 /*
   2  * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stdlib.h>
   7 #include <errno.h>
   8 #include "chan_user.h"
   9 #include "os.h"
  10
  11 static int null_chan;
  12
  13 static void *null_init(char *str, int device, const struct chan_opts *opts)
  14 {
  15         return(&null_chan);
  16 }
  17
  18 static int null_open(int input, int output, int primary, void *d,
  19                      char **dev_out)
  20 {
  21         *dev_out = NULL;
  22         return(os_open_file(DEV_NULL, of_rdwr(OPENFLAGS()), 0));
  23 }
  24
  25 static int null_read(int fd, char *c_out, void *unused)
  26 {
  27         return(-ENODEV);
  28 }
  29
  30 static void null_free(void *data)
  31 {
  32 }
  33
  34 const struct chan_ops null_ops = {
  35         .type           = "null",
  36         .init           = null_init,
  37         .open           = null_open,
  38         .close          = generic_close,
  39         .read           = null_read,
  40         .write          = generic_write,
  41         .console_write  = generic_console_write,
  42         .window_size    = generic_window_size,
  43         .free           = null_free,
  44         .winch          = 0,
  45 };
  46
  47 /*
  48  * Overrides for Emacs so that we follow Linus's tabbing style.
  49  * Emacs will notice this stuff at the end of the file and automatically
  50  * adjust the settings for this buffer only.  This must remain at the end
  51  * of the file.
  52  * ---------------------------------------------------------------------------
  53  * Local variables:
  54  * c-file-style: "linux"
  55  * End:
  56  */