1/*	$OpenBSD: cons.c,v 1.30 2022/07/02 08:50:41 visa Exp $	*/
2/*	$NetBSD: cons.c,v 1.30 1996/04/08 19:57:30 jonathan Exp $	*/
3
4/*
5 * Copyright (c) 1988 University of Utah.
6 * Copyright (c) 1990, 1993
7 *	The Regents of the University of California.  All rights reserved.
8 *
9 * This code is derived from software contributed to Berkeley by
10 * the Systems Programming Group of the University of Utah Computer
11 * Science Department.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 * 3. Neither the name of the University nor the names of its contributors
22 *    may be used to endorse or promote products derived from this software
23 *    without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * from: Utah $Hdr: cons.c 1.7 92/01/21$
38 *
39 *	@(#)cons.c	8.2 (Berkeley) 1/12/94
40 */
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/ioctl.h>
45#include <sys/tty.h>
46#include <sys/conf.h>
47#include <sys/vnode.h>
48
49#include <dev/cons.h>
50
51struct	tty *constty = NULL;		/* virtual console output device */
52struct	vnode *cn_devvp = NULLVP;	/* vnode for underlying device. */
53
54int
55cnopen(dev_t dev, int flag, int mode, struct proc *p)
56{
57	dev_t cndev;
58
59	if (cn_tab == NULL)
60		return (0);
61
62	/*
63	 * always open the 'real' console device, so we don't get nailed
64	 * later.  This follows normal device semantics; they always get
65	 * open() calls.
66	 */
67	cndev = cn_tab->cn_dev;
68	if (cndev == NODEV)
69		return (ENXIO);
70#ifdef DIAGNOSTIC
71	if (cndev == dev)
72		panic("cnopen: recursive");
73#endif
74	if (cn_devvp == NULLVP) {
75		/* try to get a reference on its vnode, but fail silently */
76		cdevvp(cndev, &cn_devvp);
77	}
78	return ((*cdevsw[major(cndev)].d_open)(cndev, flag, mode, p));
79}
80
81int
82cnclose(dev_t dev, int flag, int mode, struct proc *p)
83{
84	struct vnode *vp;
85
86	if (cn_tab == NULL)
87		return (0);
88
89	/*
90	 * If the real console isn't otherwise open, close it.
91	 * If it's otherwise open, don't close it, because that'll
92	 * screw up others who have it open.
93	 */
94	dev = cn_tab->cn_dev;
95	if (cn_devvp != NULLVP) {
96		/* release our reference to real dev's vnode */
97		vrele(cn_devvp);
98		cn_devvp = NULLVP;
99	}
100	if (vfinddev(dev, VCHR, &vp) && vcount(vp))
101		return (0);
102	return ((*cdevsw[major(dev)].d_close)(dev, flag, mode, p));
103}
104
105int
106cnread(dev_t dev, struct uio *uio, int flag)
107{
108
109	/*
110	 * If we would redirect input, punt.  This will keep strange
111	 * things from happening to people who are using the real
112	 * console.  Nothing should be using /dev/console for
113	 * input (except a shell in single-user mode, but then,
114	 * one wouldn't TIOCCONS then).
115	 */
116	if (constty != NULL)
117		return 0;
118	else if (cn_tab == NULL)
119		return ENXIO;
120
121	dev = cn_tab->cn_dev;
122	return ((*cdevsw[major(dev)].d_read)(dev, uio, flag));
123}
124
125int
126cnwrite(dev_t dev, struct uio *uio, int flag)
127{
128
129	/*
130	 * Redirect output, if that's appropriate.
131	 * If there's no real console, return ENXIO.
132	 */
133	if (constty != NULL)
134		dev = constty->t_dev;
135	else if (cn_tab == NULL)
136		return ENXIO;
137	else
138		dev = cn_tab->cn_dev;
139	return ((*cdevsw[major(dev)].d_write)(dev, uio, flag));
140}
141
142int
143cnstop(struct tty *tp, int flag)
144{
145	return (0);
146}
147
148int
149cnioctl(dev_t dev, u_long cmd, caddr_t data, int flag,
150    struct proc *p)
151{
152	int error;
153
154	/*
155	 * Superuser can always use this to wrest control of console
156	 * output from the "virtual" console.
157	 */
158	if (cmd == TIOCCONS && constty != NULL) {
159		error = suser(p);
160		if (error)
161			return (error);
162		constty = NULL;
163		return (0);
164	}
165
166	/*
167	 * Redirect the ioctl, if that's appropriate.
168	 * Note that strange things can happen, if a program does
169	 * ioctls on /dev/console, then the console is redirected
170	 * out from under it.
171	 */
172	if (constty != NULL)
173		dev = constty->t_dev;
174	else if (cn_tab == NULL)
175		return ENXIO;
176	else
177		dev = cn_tab->cn_dev;
178	return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, data, flag, p));
179}
180
181int
182cnkqfilter(dev_t dev, struct knote *kn)
183{
184
185	/*
186	 * Redirect output, if that's appropriate.
187	 * If there's no real console, return 1.
188	 */
189	if (constty != NULL)
190		dev = constty->t_dev;
191	else if (cn_tab == NULL)
192		return (ENXIO);
193	else
194		dev = cn_tab->cn_dev;
195	if (cdevsw[major(dev)].d_kqfilter)
196		return ((*cdevsw[major(dev)].d_kqfilter)(dev, kn));
197	return (EOPNOTSUPP);
198}
199
200int
201cngetc(void)
202{
203
204	if (cn_tab == NULL)
205		return (0);
206	return ((*cn_tab->cn_getc)(cn_tab->cn_dev));
207}
208
209void
210cnputc(int c)
211{
212
213	if (cn_tab == NULL)
214		return;
215
216	if (c) {
217		(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
218		if (c == '\n')
219			(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
220	}
221}
222
223void
224cnpollc(int on)
225{
226	static int refcount = 0;
227
228	if (cn_tab == NULL)
229		return;
230	if (!on)
231		--refcount;
232	if (refcount == 0)
233		(*cn_tab->cn_pollc)(cn_tab->cn_dev, on);
234	if (on)
235		++refcount;
236}
237
238void
239nullcnpollc(dev_t dev, int on)
240{
241
242}
243
244void
245cnbell(u_int pitch, u_int period, u_int volume)
246{
247	if (cn_tab == NULL || cn_tab->cn_bell == NULL)
248		return;
249
250	(*cn_tab->cn_bell)(cn_tab->cn_dev, pitch, period, volume);
251}
252