1 /* $NetBSD: tty_tty.c,v 1.41 2020/05/23 23:42:43 ad 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 1.41 2020/05/23 23:42:43 ad 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 /* XXXSMP */
52 #define cttyvp(p) ((p)->p_lflag & PL_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
53
54 /*ARGSUSED*/
55 static int
cttyopen(dev_t dev,int flag,int mode,struct lwp * l)56 cttyopen(dev_t dev, int flag, int mode, struct lwp *l)
57 {
58 struct vnode *ttyvp = cttyvp(l->l_proc);
59 int error;
60
61 if (ttyvp == NULL)
62 return (ENXIO);
63 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
64 #ifdef PARANOID
65 /*
66 * Since group is tty and mode is 620 on most terminal lines
67 * and since sessions protect terminals from processes outside
68 * your session, this check is probably no longer necessary.
69 * Since it inhibits setuid root programs that later switch
70 * to another user from accessing /dev/tty, we have decided
71 * to delete this test. (mckusick 5/93)
72 */
73 error = VOP_ACCESS(ttyvp,
74 (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), l->l_cred, l);
75 if (!error)
76 #endif /* PARANOID */
77 error = VOP_OPEN(ttyvp, flag, NOCRED);
78 VOP_UNLOCK(ttyvp);
79 return (error);
80 }
81
82 /*ARGSUSED*/
83 static int
cttyread(dev_t dev,struct uio * uio,int flag)84 cttyread(dev_t dev, struct uio *uio, int flag)
85 {
86 struct vnode *ttyvp = cttyvp(curproc);
87 int error;
88
89 if (ttyvp == NULL)
90 return (EIO);
91 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
92 error = VOP_READ(ttyvp, uio, flag, NOCRED);
93 VOP_UNLOCK(ttyvp);
94 return (error);
95 }
96
97 /*ARGSUSED*/
98 static int
cttywrite(dev_t dev,struct uio * uio,int flag)99 cttywrite(dev_t dev, struct uio *uio, int flag)
100 {
101 struct vnode *ttyvp = cttyvp(curproc);
102 int error;
103
104 if (ttyvp == NULL)
105 return (EIO);
106 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
107 error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
108 VOP_UNLOCK(ttyvp);
109 return (error);
110 }
111
112 /*ARGSUSED*/
113 static int
cttyioctl(dev_t dev,u_long cmd,void * addr,int flag,struct lwp * l)114 cttyioctl(dev_t dev, u_long cmd, void *addr, int flag, struct lwp *l)
115 {
116 struct vnode *ttyvp = cttyvp(l->l_proc);
117 int rv;
118
119 if (ttyvp == NULL)
120 return (EIO);
121 if (cmd == TIOCSCTTY) /* XXX */
122 return (EINVAL);
123 if (cmd == TIOCNOTTY) {
124 mutex_enter(&proc_lock);
125 if (!SESS_LEADER(l->l_proc)) {
126 l->l_proc->p_lflag &= ~PL_CONTROLT;
127 rv = 0;
128 } else
129 rv = EINVAL;
130 mutex_exit(&proc_lock);
131 return (rv);
132 }
133 return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED));
134 }
135
136 /*ARGSUSED*/
137 static int
cttypoll(dev_t dev,int events,struct lwp * l)138 cttypoll(dev_t dev, int events, struct lwp *l)
139 {
140 struct vnode *ttyvp = cttyvp(l->l_proc);
141
142 if (ttyvp == NULL)
143 return (seltrue(dev, events, l));
144 return (VOP_POLL(ttyvp, events));
145 }
146
147 static int
cttykqfilter(dev_t dev,struct knote * kn)148 cttykqfilter(dev_t dev, struct knote *kn)
149 {
150 /* This is called from filt_fileattach() by the attaching process. */
151 struct proc *p = curproc;
152 struct vnode *ttyvp = cttyvp(p);
153
154 if (ttyvp == NULL)
155 return (1);
156 return (VOP_KQFILTER(ttyvp, kn));
157 }
158
159 const struct cdevsw ctty_cdevsw = {
160 .d_open = cttyopen,
161 .d_close = nullclose,
162 .d_read = cttyread,
163 .d_write = cttywrite,
164 .d_ioctl = cttyioctl,
165 .d_stop = nullstop,
166 .d_tty = notty,
167 .d_poll = cttypoll,
168 .d_mmap = nommap,
169 .d_kqfilter = cttykqfilter,
170 .d_discard = nodiscard,
171 .d_flag = D_TTY
172 };
173