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 */
40
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD: releng/5.2/sys/kern/tty_conf.c 116182 2003-06-11 00:56:59Z obrien $");
43
44 #include "opt_compat.h"
45
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/tty.h>
49 #include <sys/conf.h>
50
51 #ifndef MAXLDISC
52 #define MAXLDISC 9
53 #endif
54
55 static l_open_t l_noopen;
56 static l_close_t l_noclose;
57 static l_rint_t l_norint;
58 static l_start_t l_nostart;
59
60 /*
61 * XXX it probably doesn't matter what the entries other than the l_open
62 * entry are here. The l_nullioctl and ttymodem entries still look fishy.
63 * Reconsider the removal of nullmodem anyway. It was too much like
64 * ttymodem, but a completely null version might be useful.
65 */
66 #define NODISC(n) \
67 { l_noopen, l_noclose, l_noread, l_nowrite, \
68 l_nullioctl, l_norint, l_nostart, ttymodem }
69
70 struct linesw linesw[MAXLDISC] =
71 {
72 /* 0- termios */
73 { ttyopen, ttylclose, ttread, ttwrite,
74 l_nullioctl, ttyinput, ttstart, ttymodem },
75 NODISC(1), /* 1- defunct */
76 /* 2- NTTYDISC */
77 #ifdef COMPAT_43
78 { ttyopen, ttylclose, ttread, ttwrite,
79 l_nullioctl, ttyinput, ttstart, ttymodem },
80 #else
81 NODISC(2),
82 #endif
83 NODISC(3), /* loadable */
84 NODISC(4), /* SLIPDISC */
85 NODISC(5), /* PPPDISC */
86 NODISC(6), /* NETGRAPHDISC */
87 NODISC(7), /* loadable */
88 NODISC(8), /* loadable */
89 };
90
91 int nlinesw = sizeof (linesw) / sizeof (linesw[0]);
92
93 static struct linesw nodisc = NODISC(0);
94
95 #define LOADABLE_LDISC 7
96 /*
97 * ldisc_register: Register a line discipline.
98 *
99 * discipline: Index for discipline to load, or LDISC_LOAD for us to choose.
100 * linesw_p: Pointer to linesw_p.
101 *
102 * Returns: Index used or -1 on failure.
103 */
104 int
105 ldisc_register(discipline, linesw_p)
106 int discipline;
107 struct linesw *linesw_p;
108 {
109 int slot = -1;
110
111 if (discipline == LDISC_LOAD) {
112 int i;
113 for (i = LOADABLE_LDISC; i < MAXLDISC; i++)
114 if (bcmp(linesw + i, &nodisc, sizeof(nodisc)) == 0) {
115 slot = i;
116 }
117 }
118 else if (discipline >= 0 && discipline < MAXLDISC) {
119 slot = discipline;
120 }
121
122 if (slot != -1 && linesw_p)
123 linesw[slot] = *linesw_p;
124
125 return slot;
126 }
127
128 /*
129 * ldisc_deregister: Deregister a line discipline obtained with
130 * ldisc_register.
131 *
132 * discipline: Index for discipline to unload.
133 */
134 void
135 ldisc_deregister(discipline)
136 int discipline;
137 {
138 if (discipline < MAXLDISC) {
139 linesw[discipline] = nodisc;
140 }
141 }
142
143 static int
144 l_noopen(dev, tp)
145 dev_t dev;
146 struct tty *tp;
147 {
148
149 return (ENODEV);
150 }
151
152 static int
153 l_noclose(tp, flag)
154 struct tty *tp;
155 int flag;
156 {
157
158 return (ENODEV);
159 }
160
161 int
162 l_noread(tp, uio, flag)
163 struct tty *tp;
164 struct uio *uio;
165 int flag;
166 {
167
168 return (ENODEV);
169 }
170
171 int
172 l_nowrite(tp, uio, flag)
173 struct tty *tp;
174 struct uio *uio;
175 int flag;
176 {
177
178 return (ENODEV);
179 }
180
181 static int
182 l_norint(c, tp)
183 int c;
184 struct tty *tp;
185 {
186
187 return (ENODEV);
188 }
189
190 static int
191 l_nostart(tp)
192 struct tty *tp;
193 {
194
195 return (ENODEV);
196 }
197
198 /*
199 * Do nothing specific version of line
200 * discipline specific ioctl command.
201 */
202 int
203 l_nullioctl(tp, cmd, data, flags, td)
204 struct tty *tp;
205 u_long cmd;
206 char *data;
207 int flags;
208 struct thread *td;
209 {
210
211 return (ENOIOCTL);
212 }
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