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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/tty/n_null.c
1 #include <linux/types.h>
2 #include <linux/errno.h>
4 #include <linux/module.h>
7 * n_null.c - Null line discipline used in the failure path
9 * Copyright (C) Intel 2017
11 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2
15 * as published by the Free Software Foundation.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25 static int n_null_open(struct tty_struct
*tty
)
30 static void n_null_close(struct tty_struct
*tty
)
34 static ssize_t
n_null_read(struct tty_struct
*tty
, struct file
*file
,
35 unsigned char __user
* buf
, size_t nr
)
40 static ssize_t
n_null_write(struct tty_struct
*tty
, struct file
*file
,
41 const unsigned char *buf
, size_t nr
)
46 static void n_null_receivebuf(struct tty_struct
*tty
,
47 const unsigned char *cp
, char *fp
,
52 static struct tty_ldisc_ops null_ldisc
= {
54 .magic
= TTY_LDISC_MAGIC
,
57 .close
= n_null_close
,
59 .write
= n_null_write
,
60 .receive_buf
= n_null_receivebuf
63 static int __init
n_null_init(void)
65 BUG_ON(tty_register_ldisc(N_NULL
, &null_ldisc
));
69 static void __exit
n_null_exit(void)
71 tty_unregister_ldisc(N_NULL
);
74 module_init(n_null_init
);
75 module_exit(n_null_exit
);
77 MODULE_LICENSE("GPL");
78 MODULE_AUTHOR("Alan Cox");
79 MODULE_ALIAS_LDISC(N_NULL
);
80 MODULE_DESCRIPTION("Null ldisc driver");