Commit | Line | Data |
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e3b3d0f5 | 1 | // SPDX-License-Identifier: GPL-2.0 |
8a8dabf2 AC |
2 | #include <linux/types.h> |
3 | #include <linux/errno.h> | |
4 | #include <linux/tty.h> | |
5 | #include <linux/module.h> | |
6 | ||
7 | /* | |
8 | * n_null.c - Null line discipline used in the failure path | |
9 | * | |
10 | * Copyright (C) Intel 2017 | |
8a8dabf2 AC |
11 | */ |
12 | ||
49b8220c JSS |
13 | static ssize_t n_null_read(struct tty_struct *tty, struct file *file, u8 *buf, |
14 | size_t nr, void **cookie, unsigned long offset) | |
8a8dabf2 AC |
15 | { |
16 | return -EOPNOTSUPP; | |
17 | } | |
18 | ||
19 | static ssize_t n_null_write(struct tty_struct *tty, struct file *file, | |
49b8220c | 20 | const u8 *buf, size_t nr) |
8a8dabf2 AC |
21 | { |
22 | return -EOPNOTSUPP; | |
23 | } | |
24 | ||
8a8dabf2 AC |
25 | static struct tty_ldisc_ops null_ldisc = { |
26 | .owner = THIS_MODULE, | |
fbadf70a | 27 | .num = N_NULL, |
8a8dabf2 | 28 | .name = "n_null", |
8a8dabf2 AC |
29 | .read = n_null_read, |
30 | .write = n_null_write, | |
8a8dabf2 AC |
31 | }; |
32 | ||
33 | static int __init n_null_init(void) | |
34 | { | |
fbadf70a | 35 | BUG_ON(tty_register_ldisc(&null_ldisc)); |
8a8dabf2 AC |
36 | return 0; |
37 | } | |
38 | ||
39 | static void __exit n_null_exit(void) | |
40 | { | |
f81ee8b8 | 41 | tty_unregister_ldisc(&null_ldisc); |
8a8dabf2 AC |
42 | } |
43 | ||
44 | module_init(n_null_init); | |
45 | module_exit(n_null_exit); | |
46 | ||
47 | MODULE_LICENSE("GPL"); | |
48 | MODULE_AUTHOR("Alan Cox"); | |
49 | MODULE_ALIAS_LDISC(N_NULL); | |
50 | MODULE_DESCRIPTION("Null ldisc driver"); |