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/arch/um/drivers/null.c

http://github.com/mirrors/linux
C | 51 lines | 37 code | 9 blank | 5 comment | 0 complexity | b1b67cff511f4c596a664800705463c9 MD5 | raw file
 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
 4 */
 5
 6#include <stddef.h>
 7#include <errno.h>
 8#include <fcntl.h>
 9#include "chan_user.h"
10#include <os.h>
11
12/* This address is used only as a unique identifier */
13static int null_chan;
14
15static void *null_init(char *str, int device, const struct chan_opts *opts)
16{
17	return &null_chan;
18}
19
20static int null_open(int input, int output, int primary, void *d,
21		     char **dev_out)
22{
23	int fd;
24
25	*dev_out = NULL;
26
27	fd = open(DEV_NULL, O_RDWR);
28	return (fd < 0) ? -errno : fd;
29}
30
31static int null_read(int fd, char *c_out, void *unused)
32{
33	return -ENODEV;
34}
35
36static void null_free(void *data)
37{
38}
39
40const struct chan_ops null_ops = {
41	.type		= "null",
42	.init		= null_init,
43	.open		= null_open,
44	.close		= generic_close,
45	.read		= null_read,
46	.write		= generic_write,
47	.console_write	= generic_console_write,
48	.window_size	= generic_window_size,
49	.free		= null_free,
50	.winch		= 0,
51};