tty_tty.c revision 33679 
1/*-
2 * Copyright (c) 1982, 1986, 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 *	@(#)tty_tty.c	8.2 (Berkeley) 9/23/93
34 * $Id: tty_tty.c,v 1.22 1998/01/24 02:54:35 eivind Exp $
35 */
36
37/*
38 * Indirect driver for controlling tty.
39 */
40
41#include "opt_devfs.h"
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/conf.h>
46#include <sys/lock.h>
47#include <sys/proc.h>
48#include <sys/ttycom.h>
49#include <sys/vnode.h>
50#include <sys/kernel.h>
51#ifdef DEVFS
52#include <sys/devfsext.h>
53#endif /*DEVFS*/
54
55static	d_open_t	cttyopen;
56static	d_read_t	cttyread;
57static	d_write_t	cttywrite;
58static	d_ioctl_t	cttyioctl;
59static	d_poll_t	cttypoll;
60
61#define CDEV_MAJOR 1
62/* Don't make static, fdesc_vnops uses this. */
63struct cdevsw ctty_cdevsw =
64	{ cttyopen,	nullclose,	cttyread,	cttywrite,	/*1*/
65	  cttyioctl,	nullstop,	nullreset,	nodevtotty,/* tty */
66	  cttypoll,	nommap,		NULL,	"ctty",	NULL,	-1 };
67
68
69#define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
70
71/*ARGSUSED*/
72static	int
73cttyopen(dev, flag, mode, p)
74	dev_t dev;
75	int flag, mode;
76	struct proc *p;
77{
78	struct vnode *ttyvp = cttyvp(p);
79	int error;
80
81	if (ttyvp == NULL)
82		return (ENXIO);
83	vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
84#ifdef PARANOID
85	/*
86	 * Since group is tty and mode is 620 on most terminal lines
87	 * and since sessions protect terminals from processes outside
88	 * your session, this check is probably no longer necessary.
89	 * Since it inhibits setuid root programs that later switch
90	 * to another user from accessing /dev/tty, we have decided
91	 * to delete this test. (mckusick 5/93)
92	 */
93	error = VOP_ACCESS(ttyvp,
94	  (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
95	if (!error)
96#endif /* PARANOID */
97		error = VOP_OPEN(ttyvp, flag, NOCRED, p);
98	VOP_UNLOCK(ttyvp, 0, p);
99	return (error);
100}
101
102/*ARGSUSED*/
103static	int
104cttyread(dev, uio, flag)
105	dev_t dev;
106	struct uio *uio;
107	int flag;
108{
109	struct proc *p = uio->uio_procp;
110	register struct vnode *ttyvp = cttyvp(p);
111	int error;
112
113	if (ttyvp == NULL)
114		return (EIO);
115	vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
116	error = VOP_READ(ttyvp, uio, flag, NOCRED);
117	VOP_UNLOCK(ttyvp, 0, p);
118	return (error);
119}
120
121/*ARGSUSED*/
122static	int
123cttywrite(dev, uio, flag)
124	dev_t dev;
125	struct uio *uio;
126	int flag;
127{
128	struct proc *p = uio->uio_procp;
129	struct vnode *ttyvp = cttyvp(uio->uio_procp);
130	int error;
131
132	if (ttyvp == NULL)
133		return (EIO);
134	vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
135	error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
136	VOP_UNLOCK(ttyvp, 0, p);
137	return (error);
138}
139
140/*ARGSUSED*/
141static	int
142cttyioctl(dev, cmd, addr, flag, p)
143	dev_t dev;
144	int cmd;
145	caddr_t addr;
146	int flag;
147	struct proc *p;
148{
149	struct vnode *ttyvp = cttyvp(p);
150
151	if (ttyvp == NULL)
152		return (EIO);
153	if (cmd == TIOCSCTTY)  /* don't allow controlling tty to be set    */
154		return EINVAL; /* to controlling tty -- infinite recursion */
155	if (cmd == TIOCNOTTY) {
156		if (!SESS_LEADER(p)) {
157			p->p_flag &= ~P_CONTROLT;
158			return (0);
159		} else
160			return (EINVAL);
161	}
162	return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
163}
164
165/*ARGSUSED*/
166static	int
167cttypoll(dev, events, p)
168	dev_t dev;
169	int events;
170	struct proc *p;
171{
172	struct vnode *ttyvp = cttyvp(p);
173
174	if (ttyvp == NULL)
175		/* try operation to get EOF/failure */
176		return (seltrue(dev, events, p));
177	return (VOP_POLL(ttyvp, events, p->p_ucred, p));
178}
179
180static	int	ctty_devsw_installed;
181#ifdef DEVFS
182static 	void	*ctty_devfs_token;
183#endif
184
185static void ctty_drvinit __P((void *unused));
186static void
187ctty_drvinit(unused)
188	void *unused;
189{
190	dev_t dev;
191
192	if( ! ctty_devsw_installed ) {
193		dev = makedev(CDEV_MAJOR,0);
194		cdevsw_add(&dev,&ctty_cdevsw,NULL);
195		ctty_devsw_installed = 1;
196#ifdef DEVFS
197		ctty_devfs_token =
198			devfs_add_devswf(&ctty_cdevsw, 0, DV_CHR, 0, 0,
199					0666, "tty");
200#endif
201    	}
202}
203
204SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL)
205