FreeBSD/Linux Kernel Cross Reference
sys/kern/tty_tty.c
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 1.11.4.1 1999/09/05 08:15:31 peter Exp $
35 */
36
37 /*
38 * Indirect driver for controlling tty.
39 */
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/conf.h>
43 #include <sys/ioctl.h>
44 #include <sys/proc.h>
45 #include <sys/tty.h>
46 #include <sys/vnode.h>
47 #include <sys/file.h>
48 #include <sys/kernel.h>
49 #ifdef DEVFS
50 #include <sys/devfsext.h>
51 #endif /*DEVFS*/
52
53 static d_open_t cttyopen;
54 static d_read_t cttyread;
55 static d_write_t cttywrite;
56 static d_ioctl_t cttyioctl;
57 static d_select_t cttyselect;
58
59 #define CDEV_MAJOR 1
60 /* Don't make static, fdesc_vnops uses this. */
61 struct cdevsw ctty_cdevsw =
62 { cttyopen, nullclose, cttyread, cttywrite, /*1*/
63 cttyioctl, nullstop, nullreset, nodevtotty,/* tty */
64 cttyselect, nommap, NULL, "ctty", NULL, -1 };
65
66
67 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
68
69 /*ARGSUSED*/
70 static int
71 cttyopen(dev, flag, mode, p)
72 dev_t dev;
73 int flag, mode;
74 struct proc *p;
75 {
76 struct vnode *ttyvp = cttyvp(p);
77 int error;
78
79 if (ttyvp == NULL)
80 return (ENXIO);
81 VOP_LOCK(ttyvp);
82 #ifdef PARANOID
83 /*
84 * Since group is tty and mode is 620 on most terminal lines
85 * and since sessions protect terminals from processes outside
86 * your session, this check is probably no longer necessary.
87 * Since it inhibits setuid root programs that later switch
88 * to another user from accessing /dev/tty, we have decided
89 * to delete this test. (mckusick 5/93)
90 */
91 error = VOP_ACCESS(ttyvp,
92 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
93 if (!error)
94 #endif /* PARANOID */
95 error = VOP_OPEN(ttyvp, flag, NOCRED, p);
96 VOP_UNLOCK(ttyvp);
97 return (error);
98 }
99
100 /*ARGSUSED*/
101 static int
102 cttyread(dev, uio, flag)
103 dev_t dev;
104 struct uio *uio;
105 int flag;
106 {
107 register struct vnode *ttyvp = cttyvp(uio->uio_procp);
108 int error;
109
110 if (ttyvp == NULL)
111 return (EIO);
112 VOP_LOCK(ttyvp);
113 error = VOP_READ(ttyvp, uio, flag, NOCRED);
114 VOP_UNLOCK(ttyvp);
115 return (error);
116 }
117
118 /*ARGSUSED*/
119 static int
120 cttywrite(dev, uio, flag)
121 dev_t dev;
122 struct uio *uio;
123 int flag;
124 {
125 register struct vnode *ttyvp = cttyvp(uio->uio_procp);
126 int error;
127
128 if (ttyvp == NULL)
129 return (EIO);
130 VOP_LOCK(ttyvp);
131 error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
132 VOP_UNLOCK(ttyvp);
133 return (error);
134 }
135
136 /*ARGSUSED*/
137 static int
138 cttyioctl(dev, cmd, addr, flag, p)
139 dev_t dev;
140 int cmd;
141 caddr_t addr;
142 int flag;
143 struct proc *p;
144 {
145 struct vnode *ttyvp = cttyvp(p);
146
147 if (ttyvp == NULL)
148 return (EIO);
149 if (cmd == TIOCSCTTY) /* don't allow controlling tty to be set */
150 return EINVAL; /* to controlling tty -- infinite recursion */
151 if (cmd == TIOCNOTTY) {
152 if (!SESS_LEADER(p)) {
153 p->p_flag &= ~P_CONTROLT;
154 return (0);
155 } else
156 return (EINVAL);
157 }
158 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
159 }
160
161 /*ARGSUSED*/
162 static int
163 cttyselect(dev, flag, p)
164 dev_t dev;
165 int flag;
166 struct proc *p;
167 {
168 struct vnode *ttyvp = cttyvp(p);
169
170 if (ttyvp == NULL)
171 return (1); /* try operation to get EOF/failure */
172 return (VOP_SELECT(ttyvp, flag, FREAD|FWRITE, NOCRED, p));
173 }
174
175 static ctty_devsw_installed = 0;
176 #ifdef DEVFS
177 static void *ctty_devfs_token;
178 #endif
179
180 static void
181 ctty_drvinit(void *unused)
182 {
183 dev_t dev;
184
185 if( ! ctty_devsw_installed ) {
186 dev = makedev(CDEV_MAJOR,0);
187 cdevsw_add(&dev,&ctty_cdevsw,NULL);
188 ctty_devsw_installed = 1;
189 #ifdef DEVFS
190 ctty_devfs_token =
191 devfs_add_devswf(&ctty_cdevsw, 0, DV_CHR, 0, 0,
192 0666, "tty");
193 #endif
194 }
195 }
196
197 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL)
198
199
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