FreeBSD/Linux Kernel Cross Reference
sys/kern/tty_conf.c
1 /*-
2 * Copyright (c) 1982, 1986, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)tty_conf.c 8.4 (Berkeley) 1/21/94
39 * $FreeBSD$
40 */
41
42 #include "opt_compat.h"
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/tty.h>
47 #include <sys/conf.h>
48
49 #ifndef MAXLDISC
50 #define MAXLDISC 9
51 #endif
52
53 static l_open_t l_noopen;
54 static l_close_t l_noclose;
55 static l_rint_t l_norint;
56 static l_start_t l_nostart;
57
58 /*
59 * XXX it probably doesn't matter what the entries other than the l_open
60 * entry are here. The l_nullioctl and ttymodem entries still look fishy.
61 * Reconsider the removal of nullmodem anyway. It was too much like
62 * ttymodem, but a completely null version might be useful.
63 */
64 #define NODISC(n) \
65 { l_noopen, l_noclose, l_noread, l_nowrite, \
66 l_nullioctl, l_norint, l_nostart, ttymodem }
67
68 struct linesw linesw[MAXLDISC] =
69 {
70 /* 0- termios */
71 { ttyopen, ttylclose, ttread, ttwrite,
72 l_nullioctl, ttyinput, ttstart, ttymodem },
73 NODISC(1), /* 1- defunct */
74 /* 2- NTTYDISC */
75 #ifdef COMPAT_43
76 { ttyopen, ttylclose, ttread, ttwrite,
77 l_nullioctl, ttyinput, ttstart, ttymodem },
78 #else
79 NODISC(2),
80 #endif
81 NODISC(3), /* loadable */
82 NODISC(4), /* SLIPDISC */
83 NODISC(5), /* PPPDISC */
84 NODISC(6), /* NETGRAPHDISC */
85 NODISC(7), /* loadable */
86 NODISC(8), /* loadable */
87 };
88
89 int nlinesw = sizeof (linesw) / sizeof (linesw[0]);
90
91 static struct linesw nodisc = NODISC(0);
92
93 #define LOADABLE_LDISC 7
94 /*
95 * ldisc_register: Register a line discipline.
96 *
97 * discipline: Index for discipline to load, or LDISC_LOAD for us to choose.
98 * linesw_p: Pointer to linesw_p.
99 *
100 * Returns: Index used or -1 on failure.
101 */
102 int
103 ldisc_register(discipline, linesw_p)
104 int discipline;
105 struct linesw *linesw_p;
106 {
107 int slot = -1;
108
109 if (discipline == LDISC_LOAD) {
110 int i;
111 for (i = LOADABLE_LDISC; i < MAXLDISC; i++)
112 if (bcmp(linesw + i, &nodisc, sizeof(nodisc)) == 0) {
113 slot = i;
114 }
115 }
116 else if (discipline >= 0 && discipline < MAXLDISC) {
117 slot = discipline;
118 }
119
120 if (slot != -1 && linesw_p)
121 linesw[slot] = *linesw_p;
122
123 return slot;
124 }
125
126 /*
127 * ldisc_deregister: Deregister a line discipline obtained with
128 * ldisc_register.
129 *
130 * discipline: Index for discipline to unload.
131 */
132 void
133 ldisc_deregister(discipline)
134 int discipline;
135 {
136 if (discipline < MAXLDISC) {
137 linesw[discipline] = nodisc;
138 }
139 }
140
141 static int
142 l_noopen(dev, tp)
143 dev_t dev;
144 struct tty *tp;
145 {
146
147 return (ENODEV);
148 }
149
150 static int
151 l_noclose(tp, flag)
152 struct tty *tp;
153 int flag;
154 {
155
156 return (ENODEV);
157 }
158
159 int
160 l_noread(tp, uio, flag)
161 struct tty *tp;
162 struct uio *uio;
163 int flag;
164 {
165
166 return (ENODEV);
167 }
168
169 int
170 l_nowrite(tp, uio, flag)
171 struct tty *tp;
172 struct uio *uio;
173 int flag;
174 {
175
176 return (ENODEV);
177 }
178
179 static int
180 l_norint(c, tp)
181 int c;
182 struct tty *tp;
183 {
184
185 return (ENODEV);
186 }
187
188 static int
189 l_nostart(tp)
190 struct tty *tp;
191 {
192
193 return (ENODEV);
194 }
195
196 /*
197 * Do nothing specific version of line
198 * discipline specific ioctl command.
199 */
200 int
201 l_nullioctl(tp, cmd, data, flags, p)
202 struct tty *tp;
203 u_long cmd;
204 char *data;
205 int flags;
206 struct proc *p;
207 {
208
209 return (ENOIOCTL);
210 }
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