xref: /dragonfly/sys/kern/tty_tty.c (revision 1de703da)
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  * $DragonFly: src/sys/kern/tty_tty.c,v 1.2 2003/06/17 04:28:41 dillon Exp $
36  */
37 
38 /*
39  * Indirect driver for controlling tty.
40  */
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/conf.h>
45 #include <sys/lock.h>
46 #include <sys/proc.h>
47 #include <sys/ttycom.h>
48 #include <sys/vnode.h>
49 #include <sys/kernel.h>
50 
51 static	d_open_t	cttyopen;
52 static	d_read_t	cttyread;
53 static	d_write_t	cttywrite;
54 static	d_ioctl_t	cttyioctl;
55 static	d_poll_t	cttypoll;
56 
57 #define	CDEV_MAJOR	1
58 /* Don't make this static, since fdesc_vnops uses it. */
59 struct cdevsw ctty_cdevsw = {
60 	/* open */	cttyopen,
61 	/* close */	nullclose,
62 	/* read */	cttyread,
63 	/* write */	cttywrite,
64 	/* ioctl */	cttyioctl,
65 	/* poll */	cttypoll,
66 	/* mmap */	nommap,
67 	/* strategy */	nostrategy,
68 	/* name */	"ctty",
69 	/* maj */	CDEV_MAJOR,
70 	/* dump */	nodump,
71 	/* psize */	nopsize,
72 	/* flags */	D_TTY,
73 	/* bmaj */	-1
74 };
75 
76 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
77 
78 /*ARGSUSED*/
79 static	int
80 cttyopen(dev, flag, mode, p)
81 	dev_t dev;
82 	int flag, mode;
83 	struct proc *p;
84 {
85 	struct vnode *ttyvp = cttyvp(p);
86 	int error;
87 
88 	if (ttyvp == NULL)
89 		return (ENXIO);
90 	vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
91 #ifdef PARANOID
92 	/*
93 	 * Since group is tty and mode is 620 on most terminal lines
94 	 * and since sessions protect terminals from processes outside
95 	 * your session, this check is probably no longer necessary.
96 	 * Since it inhibits setuid root programs that later switch
97 	 * to another user from accessing /dev/tty, we have decided
98 	 * to delete this test. (mckusick 5/93)
99 	 */
100 	error = VOP_ACCESS(ttyvp,
101 	  (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
102 	if (!error)
103 #endif /* PARANOID */
104 		error = VOP_OPEN(ttyvp, flag, NOCRED, p);
105 	VOP_UNLOCK(ttyvp, 0, p);
106 	return (error);
107 }
108 
109 /*ARGSUSED*/
110 static	int
111 cttyread(dev, uio, flag)
112 	dev_t dev;
113 	struct uio *uio;
114 	int flag;
115 {
116 	struct proc *p = uio->uio_procp;
117 	register struct vnode *ttyvp = cttyvp(p);
118 	int error;
119 
120 	if (ttyvp == NULL)
121 		return (EIO);
122 	vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
123 	error = VOP_READ(ttyvp, uio, flag, NOCRED);
124 	VOP_UNLOCK(ttyvp, 0, p);
125 	return (error);
126 }
127 
128 /*ARGSUSED*/
129 static	int
130 cttywrite(dev, uio, flag)
131 	dev_t dev;
132 	struct uio *uio;
133 	int flag;
134 {
135 	struct proc *p = uio->uio_procp;
136 	struct vnode *ttyvp = cttyvp(uio->uio_procp);
137 	int error;
138 
139 	if (ttyvp == NULL)
140 		return (EIO);
141 	vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
142 	error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
143 	VOP_UNLOCK(ttyvp, 0, p);
144 	return (error);
145 }
146 
147 /*ARGSUSED*/
148 static	int
149 cttyioctl(dev, cmd, addr, flag, p)
150 	dev_t dev;
151 	u_long cmd;
152 	caddr_t addr;
153 	int flag;
154 	struct proc *p;
155 {
156 	struct vnode *ttyvp = cttyvp(p);
157 
158 	if (ttyvp == NULL)
159 		return (EIO);
160 	if (cmd == TIOCSCTTY)  /* don't allow controlling tty to be set    */
161 		return EINVAL; /* to controlling tty -- infinite recursion */
162 	if (cmd == TIOCNOTTY) {
163 		if (!SESS_LEADER(p)) {
164 			p->p_flag &= ~P_CONTROLT;
165 			return (0);
166 		} else
167 			return (EINVAL);
168 	}
169 	return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
170 }
171 
172 /*ARGSUSED*/
173 static	int
174 cttypoll(dev, events, p)
175 	dev_t dev;
176 	int events;
177 	struct proc *p;
178 {
179 	struct vnode *ttyvp = cttyvp(p);
180 
181 	if (ttyvp == NULL)
182 		/* try operation to get EOF/failure */
183 		return (seltrue(dev, events, p));
184 	return (VOP_POLL(ttyvp, events, p->p_ucred, p));
185 }
186 
187 static void ctty_drvinit __P((void *unused));
188 static void
189 ctty_drvinit(unused)
190 	void *unused;
191 {
192 
193 	make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "tty");
194 }
195 
196 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL)
197