Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sys / kern / tty_tty.c
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MD
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 * $FreeBSD: src/sys/kern/tty_tty.c,v 1.30 1999/09/25 18:24:24 phk Exp $
35 */
36
37/*
38 * Indirect driver for controlling tty.
39 */
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/conf.h>
44#include <sys/lock.h>
45#include <sys/proc.h>
46#include <sys/ttycom.h>
47#include <sys/vnode.h>
48#include <sys/kernel.h>
49
50static d_open_t cttyopen;
51static d_read_t cttyread;
52static d_write_t cttywrite;
53static d_ioctl_t cttyioctl;
54static d_poll_t cttypoll;
55
56#define CDEV_MAJOR 1
57/* Don't make this static, since fdesc_vnops uses it. */
58struct cdevsw ctty_cdevsw = {
59 /* open */ cttyopen,
60 /* close */ nullclose,
61 /* read */ cttyread,
62 /* write */ cttywrite,
63 /* ioctl */ cttyioctl,
64 /* poll */ cttypoll,
65 /* mmap */ nommap,
66 /* strategy */ nostrategy,
67 /* name */ "ctty",
68 /* maj */ CDEV_MAJOR,
69 /* dump */ nodump,
70 /* psize */ nopsize,
71 /* flags */ D_TTY,
72 /* bmaj */ -1
73};
74
75#define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
76
77/*ARGSUSED*/
78static int
79cttyopen(dev, flag, mode, p)
80 dev_t dev;
81 int flag, mode;
82 struct proc *p;
83{
84 struct vnode *ttyvp = cttyvp(p);
85 int error;
86
87 if (ttyvp == NULL)
88 return (ENXIO);
89 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
90#ifdef PARANOID
91 /*
92 * Since group is tty and mode is 620 on most terminal lines
93 * and since sessions protect terminals from processes outside
94 * your session, this check is probably no longer necessary.
95 * Since it inhibits setuid root programs that later switch
96 * to another user from accessing /dev/tty, we have decided
97 * to delete this test. (mckusick 5/93)
98 */
99 error = VOP_ACCESS(ttyvp,
100 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
101 if (!error)
102#endif /* PARANOID */
103 error = VOP_OPEN(ttyvp, flag, NOCRED, p);
104 VOP_UNLOCK(ttyvp, 0, p);
105 return (error);
106}
107
108/*ARGSUSED*/
109static int
110cttyread(dev, uio, flag)
111 dev_t dev;
112 struct uio *uio;
113 int flag;
114{
115 struct proc *p = uio->uio_procp;
116 register struct vnode *ttyvp = cttyvp(p);
117 int error;
118
119 if (ttyvp == NULL)
120 return (EIO);
121 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
122 error = VOP_READ(ttyvp, uio, flag, NOCRED);
123 VOP_UNLOCK(ttyvp, 0, p);
124 return (error);
125}
126
127/*ARGSUSED*/
128static int
129cttywrite(dev, uio, flag)
130 dev_t dev;
131 struct uio *uio;
132 int flag;
133{
134 struct proc *p = uio->uio_procp;
135 struct vnode *ttyvp = cttyvp(uio->uio_procp);
136 int error;
137
138 if (ttyvp == NULL)
139 return (EIO);
140 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
141 error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
142 VOP_UNLOCK(ttyvp, 0, p);
143 return (error);
144}
145
146/*ARGSUSED*/
147static int
148cttyioctl(dev, cmd, addr, flag, p)
149 dev_t dev;
150 u_long cmd;
151 caddr_t addr;
152 int flag;
153 struct proc *p;
154{
155 struct vnode *ttyvp = cttyvp(p);
156
157 if (ttyvp == NULL)
158 return (EIO);
159 if (cmd == TIOCSCTTY) /* don't allow controlling tty to be set */
160 return EINVAL; /* to controlling tty -- infinite recursion */
161 if (cmd == TIOCNOTTY) {
162 if (!SESS_LEADER(p)) {
163 p->p_flag &= ~P_CONTROLT;
164 return (0);
165 } else
166 return (EINVAL);
167 }
168 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
169}
170
171/*ARGSUSED*/
172static int
173cttypoll(dev, events, p)
174 dev_t dev;
175 int events;
176 struct proc *p;
177{
178 struct vnode *ttyvp = cttyvp(p);
179
180 if (ttyvp == NULL)
181 /* try operation to get EOF/failure */
182 return (seltrue(dev, events, p));
183 return (VOP_POLL(ttyvp, events, p->p_ucred, p));
184}
185
186static void ctty_drvinit __P((void *unused));
187static void
188ctty_drvinit(unused)
189 void *unused;
190{
191
192 make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "tty");
193}
194
195SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL)