1 /*- 2 * (MPSAFE) 3 * 4 * Copyright (c) 1982, 1986, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)tty_conf.c 8.4 (Berkeley) 1/21/94 37 * $FreeBSD: src/sys/kern/tty_conf.c,v 1.16.2.1 2002/03/11 01:14:55 dd Exp $ 38 */ 39 40 #include "opt_compat.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/tty.h> 45 #include <sys/conf.h> 46 47 #ifndef MAXLDISC 48 #define MAXLDISC 9 49 #endif 50 51 static l_open_t l_noopen; 52 static l_close_t l_noclose; 53 static l_rint_t l_norint; 54 static l_start_t l_nostart; 55 56 /* 57 * XXX it probably doesn't matter what the entries other than the l_open 58 * entry are here. The l_nullioctl and ttymodem entries still look fishy. 59 * Reconsider the removal of nullmodem anyway. It was too much like 60 * ttymodem, but a completely null version might be useful. 61 */ 62 #define NODISC(n) \ 63 { l_noopen, l_noclose, l_noread, l_nowrite, \ 64 l_nullioctl, l_norint, l_nostart, ttymodem } 65 66 struct linesw linesw[MAXLDISC] = 67 { 68 /* 0- termios */ 69 { ttyopen, ttylclose, ttread, ttwrite, 70 l_nullioctl, ttyinput, ttstart, ttymodem }, 71 NODISC(1), /* 1- defunct */ 72 /* 2- NTTYDISC */ 73 #ifdef COMPAT_43 74 { ttyopen, ttylclose, ttread, ttwrite, 75 l_nullioctl, ttyinput, ttstart, ttymodem }, 76 #else 77 NODISC(2), 78 #endif 79 NODISC(3), /* loadable */ 80 NODISC(4), /* SLIPDISC */ 81 NODISC(5), /* PPPDISC */ 82 NODISC(6), /* NETGRAPHDISC */ 83 NODISC(7), /* loadable */ 84 NODISC(8), /* loadable */ 85 }; 86 87 int nlinesw = NELEM(linesw); 88 89 static struct linesw nodisc = NODISC(0); 90 91 #define LOADABLE_LDISC 7 92 /* 93 * ldisc_register: Register a line discipline. 94 * 95 * discipline: Index for discipline to load, or LDISC_LOAD for us to choose. 96 * linesw_p: Pointer to linesw_p. 97 * 98 * Returns: Index used or -1 on failure. 99 */ 100 int 101 ldisc_register(int discipline, struct linesw *linesw_p) 102 { 103 int slot = -1; 104 105 lwkt_gettoken(&tty_token); 106 if (discipline == LDISC_LOAD) { 107 int i; 108 for (i = LOADABLE_LDISC; i < MAXLDISC; i++) 109 if (bcmp(linesw + i, &nodisc, sizeof(nodisc)) == 0) { 110 slot = i; 111 } 112 } 113 else if (discipline >= 0 && discipline < MAXLDISC) { 114 slot = discipline; 115 } 116 117 if (slot != -1 && linesw_p) 118 linesw[slot] = *linesw_p; 119 120 lwkt_reltoken(&tty_token); 121 return slot; 122 } 123 124 /* 125 * ldisc_deregister: Deregister a line discipline obtained with 126 * ldisc_register. 127 * 128 * discipline: Index for discipline to unload. 129 */ 130 void 131 ldisc_deregister(int discipline) 132 { 133 lwkt_gettoken(&tty_token); 134 if (discipline < MAXLDISC) { 135 linesw[discipline] = nodisc; 136 } 137 lwkt_reltoken(&tty_token); 138 } 139 140 static int 141 l_noopen(cdev_t dev, struct tty *tp) 142 { 143 144 return (ENODEV); 145 } 146 147 static int 148 l_noclose(struct tty *tp, int flag) 149 { 150 151 return (ENODEV); 152 } 153 154 int 155 l_noread(struct tty *tp, struct uio *uio, int flag) 156 { 157 158 return (ENODEV); 159 } 160 161 int 162 l_nowrite(struct tty *tp, struct uio *uio, int flag) 163 { 164 165 return (ENODEV); 166 } 167 168 static int 169 l_norint(int c, struct tty *tp) 170 { 171 172 return (ENODEV); 173 } 174 175 static int 176 l_nostart(struct tty *tp) 177 { 178 179 return (ENODEV); 180 } 181 182 /* 183 * Do nothing specific version of line 184 * discipline specific ioctl command. 185 */ 186 int 187 l_nullioctl(struct tty *tp, u_long cmd, char *data, int flags, 188 struct ucred *cred) 189 { 190 191 return (ENOIOCTL); 192 } 193