tty_tty.c revision 130640 
1/*-
2 * Copyright (c) 2003 Poul-Henning Kamp.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26#include <sys/cdefs.h>
27__FBSDID("$FreeBSD: head/sys/kern/tty_tty.c 130640 2004-06-17 17:16:53Z phk $");
28
29#include <sys/param.h>
30#include <sys/systm.h>
31#include <sys/conf.h>
32#include <sys/kernel.h>
33#include <sys/proc.h>
34#include <sys/vnode.h>
35
36static	d_open_t	cttyopen;
37
38#define	CDEV_MAJOR	1
39
40static struct cdevsw ctty_cdevsw = {
41	.d_version =	D_VERSION,
42	.d_open =	cttyopen,
43	.d_name =	"ctty",
44	.d_maj =	CDEV_MAJOR,
45	.d_flags =	D_TTY | D_NEEDGIANT,
46};
47
48static struct cdev *ctty;
49
50static	int
51cttyopen(struct cdev *dev, int flag, int mode, struct thread *td)
52{
53
54	return (ENXIO);
55}
56
57static void
58ctty_clone(void *arg, char *name, int namelen, struct cdev **dev)
59{
60
61	if (*dev != NULL)
62		return;
63	if (strcmp(name, "tty"))
64		return;
65	if (!(curthread->td_proc->p_flag & P_CONTROLT))
66		*dev = ctty;
67	else if (curthread->td_proc->p_session->s_ttyvp == NULL)
68		*dev = ctty;
69	else
70		*dev = curthread->td_proc->p_session->s_ttyvp->v_rdev;
71}
72
73static void
74ctty_drvinit(void *unused)
75{
76
77	EVENTHANDLER_REGISTER(dev_clone, ctty_clone, 0, 1000);
78	ctty = make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "ctty");
79}
80
81SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL)
82