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: src/sys/kern/tty_conf.c,v 1.16.2.1 2002/03/11 01:14:55 dd Exp $
  40  * $DragonFly: src/sys/kern/tty_conf.c,v 1.6 2006/12/23 23:47:54 swildner Exp $
  41  */
  42
  43 #include "opt_compat.h"
  44
  45 #include <sys/param.h>
  46 #include <sys/systm.h>
  47 #include <sys/tty.h>
  48 #include <sys/conf.h>
  49
  50 #ifndef MAXLDISC
  51 #define MAXLDISC 9
  52 #endif
  53
  54 static l_open_t         l_noopen;
  55 static l_close_t        l_noclose;
  56 static l_rint_t         l_norint;
  57 static l_start_t        l_nostart;
  58
  59 /*
  60  * XXX it probably doesn't matter what the entries other than the l_open
  61  * entry are here.  The l_nullioctl and ttymodem entries still look fishy.
  62  * Reconsider the removal of nullmodem anyway.  It was too much like
  63  * ttymodem, but a completely null version might be useful.
  64  */
  65 #define NODISC(n) \
  66         { l_noopen,     l_noclose,      l_noread,       l_nowrite, \
  67           l_nullioctl,  l_norint,       l_nostart,      ttymodem }
  68
  69 struct  linesw linesw[MAXLDISC] =
  70 {
  71                                 /* 0- termios */
  72         { ttyopen,      ttylclose,      ttread,         ttwrite,
  73           l_nullioctl,  ttyinput,       ttstart,        ttymodem },
  74         NODISC(1),              /* 1- defunct */
  75                                 /* 2- NTTYDISC */
  76 #ifdef COMPAT_43
  77         { ttyopen,      ttylclose,      ttread,         ttwrite,
  78           l_nullioctl,  ttyinput,       ttstart,        ttymodem },
  79 #else
  80         NODISC(2),
  81 #endif
  82         NODISC(3),              /* loadable */
  83         NODISC(4),              /* SLIPDISC */
  84         NODISC(5),              /* PPPDISC */
  85         NODISC(6),              /* NETGRAPHDISC */
  86         NODISC(7),              /* loadable */
  87         NODISC(8),              /* loadable */
  88 };
  89
  90 int     nlinesw = sizeof (linesw) / sizeof (linesw[0]);
  91
  92 static struct linesw nodisc = NODISC(0);
  93
  94 #define LOADABLE_LDISC 7
  95 /*
  96  * ldisc_register: Register a line discipline.
  97  *
  98  * discipline: Index for discipline to load, or LDISC_LOAD for us to choose.
  99  * linesw_p:   Pointer to linesw_p.
 100  *
 101  * Returns: Index used or -1 on failure.
 102  */
 103 int
 104 ldisc_register(int discipline, struct linesw *linesw_p)
 105 {
 106         int slot = -1;
 107
 108         if (discipline == LDISC_LOAD) {
 109                 int i;
 110                 for (i = LOADABLE_LDISC; i < MAXLDISC; i++)
 111                         if (bcmp(linesw + i, &nodisc, sizeof(nodisc)) == 0) {
 112                                 slot = i;
 113                         }
 114         }
 115         else if (discipline >= 0 && discipline < MAXLDISC) {
 116                 slot = discipline;
 117         }
 118
 119         if (slot != -1 && linesw_p)
 120                 linesw[slot] = *linesw_p;
 121
 122         return slot;
 123 }
 124
 125 /*
 126  * ldisc_deregister: Deregister a line discipline obtained with
 127  * ldisc_register.
 128  *
 129  * discipline: Index for discipline to unload.
 130  */
 131 void
 132 ldisc_deregister(int discipline)
 133 {
 134         if (discipline < MAXLDISC) {
 135                 linesw[discipline] = nodisc;
 136         }
 137 }
 138
 139 static int
 140 l_noopen(cdev_t dev, struct tty *tp)
 141 {
 142
 143         return (ENODEV);
 144 }
 145
 146 static int
 147 l_noclose(struct tty *tp, int flag)
 148 {
 149
 150         return (ENODEV);
 151 }
 152
 153 int
 154 l_noread(struct tty *tp, struct uio *uio, int flag)
 155 {
 156
 157         return (ENODEV);
 158 }
 159
 160 int
 161 l_nowrite(struct tty *tp, struct uio *uio, int flag)
 162 {
 163
 164         return (ENODEV);
 165 }
 166
 167 static int
 168 l_norint(int c, struct tty *tp)
 169 {
 170
 171         return (ENODEV);
 172 }
 173
 174 static int
 175 l_nostart(struct tty *tp)
 176 {
 177
 178         return (ENODEV);
 179 }
 180
 181 /*
 182  * Do nothing specific version of line
 183  * discipline specific ioctl command.
 184  */
 185 int
 186 l_nullioctl(struct tty *tp, u_long cmd, char *data, int flags,
 187             struct ucred *cred)
 188 {
 189
 190         return (ENOIOCTL);
 191 }