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v5.4
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2019 Axis Communications AB
  4 *
  5 * Based on ttyprintk.c:
  6 *  Copyright (C) 2010 Samo Pogacnik
  7 */
  8
  9#include <linux/console.h>
 10#include <linux/module.h>
 11#include <linux/tty.h>
 12
 13static const struct tty_port_operations ttynull_port_ops;
 14static struct tty_driver *ttynull_driver;
 15static struct tty_port ttynull_port;
 16
 17static int ttynull_open(struct tty_struct *tty, struct file *filp)
 18{
 19	return tty_port_open(&ttynull_port, tty, filp);
 20}
 21
 22static void ttynull_close(struct tty_struct *tty, struct file *filp)
 23{
 24	tty_port_close(&ttynull_port, tty, filp);
 25}
 26
 27static void ttynull_hangup(struct tty_struct *tty)
 28{
 29	tty_port_hangup(&ttynull_port);
 30}
 31
 32static int ttynull_write(struct tty_struct *tty, const unsigned char *buf,
 33			 int count)
 34{
 35	return count;
 36}
 37
 38static int ttynull_write_room(struct tty_struct *tty)
 39{
 40	return 65536;
 41}
 42
 43static const struct tty_operations ttynull_ops = {
 44	.open = ttynull_open,
 45	.close = ttynull_close,
 46	.hangup = ttynull_hangup,
 47	.write = ttynull_write,
 48	.write_room = ttynull_write_room,
 49};
 50
 51static struct tty_driver *ttynull_device(struct console *c, int *index)
 52{
 53	*index = 0;
 54	return ttynull_driver;
 55}
 56
 57static struct console ttynull_console = {
 58	.name = "ttynull",
 59	.device = ttynull_device,
 60};
 61
 62static int __init ttynull_init(void)
 63{
 64	struct tty_driver *driver;
 65	int ret;
 66
 67	driver = tty_alloc_driver(1,
 68		TTY_DRIVER_RESET_TERMIOS |
 69		TTY_DRIVER_REAL_RAW |
 70		TTY_DRIVER_UNNUMBERED_NODE);
 71	if (IS_ERR(driver))
 72		return PTR_ERR(driver);
 73
 74	tty_port_init(&ttynull_port);
 75	ttynull_port.ops = &ttynull_port_ops;
 76
 77	driver->driver_name = "ttynull";
 78	driver->name = "ttynull";
 79	driver->type = TTY_DRIVER_TYPE_CONSOLE;
 80	driver->init_termios = tty_std_termios;
 81	driver->init_termios.c_oflag = OPOST | OCRNL | ONOCR | ONLRET;
 82	tty_set_operations(driver, &ttynull_ops);
 83	tty_port_link_device(&ttynull_port, driver, 0);
 84
 85	ret = tty_register_driver(driver);
 86	if (ret < 0) {
 87		put_tty_driver(driver);
 88		tty_port_destroy(&ttynull_port);
 89		return ret;
 90	}
 91
 92	ttynull_driver = driver;
 93	register_console(&ttynull_console);
 94
 95	return 0;
 96}
 97
 98static void __exit ttynull_exit(void)
 99{
100	unregister_console(&ttynull_console);
101	tty_unregister_driver(ttynull_driver);
102	put_tty_driver(ttynull_driver);
103	tty_port_destroy(&ttynull_port);
104}
105
106module_init(ttynull_init);
107module_exit(ttynull_exit);
108
109MODULE_LICENSE("GPL v2");
v6.2
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2019 Axis Communications AB
  4 *
  5 * Based on ttyprintk.c:
  6 *  Copyright (C) 2010 Samo Pogacnik
  7 */
  8
  9#include <linux/console.h>
 10#include <linux/module.h>
 11#include <linux/tty.h>
 12
 13static const struct tty_port_operations ttynull_port_ops;
 14static struct tty_driver *ttynull_driver;
 15static struct tty_port ttynull_port;
 16
 17static int ttynull_open(struct tty_struct *tty, struct file *filp)
 18{
 19	return tty_port_open(&ttynull_port, tty, filp);
 20}
 21
 22static void ttynull_close(struct tty_struct *tty, struct file *filp)
 23{
 24	tty_port_close(&ttynull_port, tty, filp);
 25}
 26
 27static void ttynull_hangup(struct tty_struct *tty)
 28{
 29	tty_port_hangup(&ttynull_port);
 30}
 31
 32static int ttynull_write(struct tty_struct *tty, const unsigned char *buf,
 33			 int count)
 34{
 35	return count;
 36}
 37
 38static unsigned int ttynull_write_room(struct tty_struct *tty)
 39{
 40	return 65536;
 41}
 42
 43static const struct tty_operations ttynull_ops = {
 44	.open = ttynull_open,
 45	.close = ttynull_close,
 46	.hangup = ttynull_hangup,
 47	.write = ttynull_write,
 48	.write_room = ttynull_write_room,
 49};
 50
 51static struct tty_driver *ttynull_device(struct console *c, int *index)
 52{
 53	*index = 0;
 54	return ttynull_driver;
 55}
 56
 57static struct console ttynull_console = {
 58	.name = "ttynull",
 59	.device = ttynull_device,
 60};
 61
 62static int __init ttynull_init(void)
 63{
 64	struct tty_driver *driver;
 65	int ret;
 66
 67	driver = tty_alloc_driver(1,
 68		TTY_DRIVER_RESET_TERMIOS |
 69		TTY_DRIVER_REAL_RAW |
 70		TTY_DRIVER_UNNUMBERED_NODE);
 71	if (IS_ERR(driver))
 72		return PTR_ERR(driver);
 73
 74	tty_port_init(&ttynull_port);
 75	ttynull_port.ops = &ttynull_port_ops;
 76
 77	driver->driver_name = "ttynull";
 78	driver->name = "ttynull";
 79	driver->type = TTY_DRIVER_TYPE_CONSOLE;
 80	driver->init_termios = tty_std_termios;
 81	driver->init_termios.c_oflag = OPOST | OCRNL | ONOCR | ONLRET;
 82	tty_set_operations(driver, &ttynull_ops);
 83	tty_port_link_device(&ttynull_port, driver, 0);
 84
 85	ret = tty_register_driver(driver);
 86	if (ret < 0) {
 87		tty_driver_kref_put(driver);
 88		tty_port_destroy(&ttynull_port);
 89		return ret;
 90	}
 91
 92	ttynull_driver = driver;
 93	register_console(&ttynull_console);
 94
 95	return 0;
 96}
 97
 98static void __exit ttynull_exit(void)
 99{
100	unregister_console(&ttynull_console);
101	tty_unregister_driver(ttynull_driver);
102	tty_driver_kref_put(ttynull_driver);
103	tty_port_destroy(&ttynull_port);
104}
105
106module_init(ttynull_init);
107module_exit(ttynull_exit);
108
109MODULE_LICENSE("GPL v2");