FreeBSD/Linux Kernel Cross Reference
sys/kern/tty_tty.c
1 /* $NetBSD: tty_tty.c,v 1.31 2006/11/01 10:17:59 yamt 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 1.31 2006/11/01 10:17:59 yamt 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 #include <sys/kauth.h>
50
51 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
52
53 /*ARGSUSED*/
54 static int
55 cttyopen(dev_t dev, int flag, int mode, struct lwp *l)
56 {
57 struct vnode *ttyvp = cttyvp(l->l_proc);
58 int error;
59
60 if (ttyvp == NULL)
61 return (ENXIO);
62 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
63 #ifdef PARANOID
64 /*
65 * Since group is tty and mode is 620 on most terminal lines
66 * and since sessions protect terminals from processes outside
67 * your session, this check is probably no longer necessary.
68 * Since it inhibits setuid root programs that later switch
69 * to another user from accessing /dev/tty, we have decided
70 * to delete this test. (mckusick 5/93)
71 */
72 error = VOP_ACCESS(ttyvp,
73 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), l->l_cred, l);
74 if (!error)
75 #endif /* PARANOID */
76 error = VOP_OPEN(ttyvp, flag, NOCRED, l);
77 VOP_UNLOCK(ttyvp, 0);
78 return (error);
79 }
80
81 /*ARGSUSED*/
82 static int
83 cttyread(dev_t dev, struct uio *uio, int flag)
84 {
85 struct vnode *ttyvp = cttyvp(curproc);
86 int error;
87
88 if (ttyvp == NULL)
89 return (EIO);
90 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
91 error = VOP_READ(ttyvp, uio, flag, NOCRED);
92 VOP_UNLOCK(ttyvp, 0);
93 return (error);
94 }
95
96 /*ARGSUSED*/
97 static int
98 cttywrite(dev_t dev, struct uio *uio, int flag)
99 {
100 struct vnode *ttyvp = cttyvp(curproc);
101 struct mount *mp;
102 int error;
103
104 if (ttyvp == NULL)
105 return (EIO);
106 mp = NULL;
107 if (ttyvp->v_type != VCHR &&
108 (error = vn_start_write(ttyvp, &mp, V_WAIT | V_PCATCH)) != 0)
109 return (error);
110 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
111 error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
112 VOP_UNLOCK(ttyvp, 0);
113 vn_finished_write(mp, 0);
114 return (error);
115 }
116
117 /*ARGSUSED*/
118 static int
119 cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct lwp *l)
120 {
121 struct vnode *ttyvp = cttyvp(l->l_proc);
122
123 if (ttyvp == NULL)
124 return (EIO);
125 if (cmd == TIOCSCTTY) /* XXX */
126 return (EINVAL);
127 if (cmd == TIOCNOTTY) {
128 if (!SESS_LEADER(l->l_proc)) {
129 l->l_proc->p_flag &= ~P_CONTROLT;
130 return (0);
131 } else
132 return (EINVAL);
133 }
134 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, l));
135 }
136
137 /*ARGSUSED*/
138 static int
139 cttypoll(dev_t dev, int events, struct lwp *l)
140 {
141 struct vnode *ttyvp = cttyvp(l->l_proc);
142
143 if (ttyvp == NULL)
144 return (seltrue(dev, events, l));
145 return (VOP_POLL(ttyvp, events, l));
146 }
147
148 static int
149 cttykqfilter(dev_t dev, struct knote *kn)
150 {
151 /* This is called from filt_fileattach() by the attaching process. */
152 struct proc *p = curproc;
153 struct vnode *ttyvp = cttyvp(p);
154
155 if (ttyvp == NULL)
156 return (1);
157 return (VOP_KQFILTER(ttyvp, kn));
158 }
159
160 const struct cdevsw ctty_cdevsw = {
161 cttyopen, nullclose, cttyread, cttywrite, cttyioctl,
162 nullstop, notty, cttypoll, nommap, cttykqfilter, D_TTY
163 };
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