FreeBSD/Linux Kernel Cross Reference
sys/kern/tty_tty.c
1 /* $NetBSD: tty_tty.c,v 1.24 2005/02/26 21:34:55 perry Exp $ */
2
3 /*-
4 * Copyright (c) 1982, 1986, 1991, 1993, 1995
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)tty_tty.c 8.2 (Berkeley) 9/23/93
32 */
33
34 /*
35 * Indirect driver for controlling tty.
36 */
37
38 #include <sys/cdefs.h>
39 __KERNEL_RCSID(0, "$NetBSD: tty_tty.c,v 1.24 2005/02/26 21:34:55 perry Exp $");
40
41 #include <sys/param.h>
42 #include <sys/systm.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/conf.h>
49
50
51 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
52
53 dev_type_open(cttyopen);
54 dev_type_read(cttyread);
55 dev_type_write(cttywrite);
56 dev_type_ioctl(cttyioctl);
57 dev_type_poll(cttypoll);
58 dev_type_kqfilter(cttykqfilter);
59
60 const struct cdevsw ctty_cdevsw = {
61 cttyopen, nullclose, cttyread, cttywrite, cttyioctl,
62 nullstop, notty, cttypoll, nommap, cttykqfilter, D_TTY
63 };
64
65 /*ARGSUSED*/
66 int
67 cttyopen(dev, flag, mode, p)
68 dev_t dev;
69 int flag, mode;
70 struct proc *p;
71 {
72 struct vnode *ttyvp = cttyvp(p);
73 int error;
74
75 if (ttyvp == NULL)
76 return (ENXIO);
77 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
78 #ifdef PARANOID
79 /*
80 * Since group is tty and mode is 620 on most terminal lines
81 * and since sessions protect terminals from processes outside
82 * your session, this check is probably no longer necessary.
83 * Since it inhibits setuid root programs that later switch
84 * to another user from accessing /dev/tty, we have decided
85 * to delete this test. (mckusick 5/93)
86 */
87 error = VOP_ACCESS(ttyvp,
88 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
89 if (!error)
90 #endif /* PARANOID */
91 error = VOP_OPEN(ttyvp, flag, NOCRED, p);
92 VOP_UNLOCK(ttyvp, 0);
93 return (error);
94 }
95
96 /*ARGSUSED*/
97 int
98 cttyread(dev, uio, flag)
99 dev_t dev;
100 struct uio *uio;
101 int flag;
102 {
103 struct vnode *ttyvp = cttyvp(uio->uio_procp);
104 int error;
105
106 if (ttyvp == NULL)
107 return (EIO);
108 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
109 error = VOP_READ(ttyvp, uio, flag, NOCRED);
110 VOP_UNLOCK(ttyvp, 0);
111 return (error);
112 }
113
114 /*ARGSUSED*/
115 int
116 cttywrite(dev, uio, flag)
117 dev_t dev;
118 struct uio *uio;
119 int flag;
120 {
121 struct vnode *ttyvp = cttyvp(uio->uio_procp);
122 struct mount *mp;
123 int error;
124
125 if (ttyvp == NULL)
126 return (EIO);
127 mp = NULL;
128 if (ttyvp->v_type != VCHR &&
129 (error = vn_start_write(ttyvp, &mp, V_WAIT | V_PCATCH)) != 0)
130 return (error);
131 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
132 error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
133 VOP_UNLOCK(ttyvp, 0);
134 vn_finished_write(mp, 0);
135 return (error);
136 }
137
138 /*ARGSUSED*/
139 int
140 cttyioctl(dev, cmd, addr, flag, p)
141 dev_t dev;
142 u_long cmd;
143 caddr_t addr;
144 int flag;
145 struct proc *p;
146 {
147 struct vnode *ttyvp = cttyvp(p);
148
149 if (ttyvp == NULL)
150 return (EIO);
151 if (cmd == TIOCSCTTY) /* XXX */
152 return (EINVAL);
153 if (cmd == TIOCNOTTY) {
154 if (!SESS_LEADER(p)) {
155 p->p_flag &= ~P_CONTROLT;
156 return (0);
157 } else
158 return (EINVAL);
159 }
160 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
161 }
162
163 /*ARGSUSED*/
164 int
165 cttypoll(dev, events, p)
166 dev_t dev;
167 int events;
168 struct proc *p;
169 {
170 struct vnode *ttyvp = cttyvp(p);
171
172 if (ttyvp == NULL)
173 return (seltrue(dev, events, p));
174 return (VOP_POLL(ttyvp, events, p));
175 }
176
177 int
178 cttykqfilter(dev, kn)
179 dev_t dev;
180 struct knote *kn;
181 {
182 /* This is called from filt_fileattach() by the attaching process. */
183 struct proc *p = curproc;
184 struct vnode *ttyvp = cttyvp(p);
185
186 if (ttyvp == NULL)
187 return (1);
188 return (VOP_KQFILTER(ttyvp, kn));
189 }
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