[linux-block.git] / drivers / tty / n_null.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/module.h>

/*
 *  n_null.c - Null line discipline used in the failure path
 *
 *  Copyright (C) Intel 2017
 */

static ssize_t n_null_read(struct tty_struct *tty, struct file *file, u8 *buf,
			   size_t nr, void **cookie, unsigned long offset)
{
	return -EOPNOTSUPP;
}

static ssize_t n_null_write(struct tty_struct *tty, struct file *file,
			    const u8 *buf, size_t nr)
{
	return -EOPNOTSUPP;
}

static struct tty_ldisc_ops null_ldisc = {
	.owner		=	THIS_MODULE,
	.num		=	N_NULL,
	.name		=	"n_null",
	.read		=	n_null_read,
	.write		=	n_null_write,
};

static int __init n_null_init(void)
{
	BUG_ON(tty_register_ldisc(&null_ldisc));
	return 0;
}

static void __exit n_null_exit(void)
{
	tty_unregister_ldisc(&null_ldisc);
}

module_init(n_null_init);
module_exit(n_null_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alan Cox");
MODULE_ALIAS_LDISC(N_NULL);
MODULE_DESCRIPTION("Null ldisc driver");
Commit	Line	Data
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	*/
8a8dabf2 AC	12
49b8220c JSS	13	static ssize_t n_null_read(struct tty_struct tty, struct file file, u8 *buf,
49b8220c JSS	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 = {
8a8dabf2 AC	26	.owner = THIS_MODULE,
fbadf70a	27	.num = N_NULL,
8a8dabf2	28	.name = "n_null",
8a8dabf2 AC	29	.read = n_null_read,
8a8dabf2 AC	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");