sys/kern/tty_conf.c

   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. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Berkeley and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  *
  40  *      @(#)tty_conf.c  8.4 (Berkeley) 1/21/94
  41  * $FreeBSD: src/sys/kern/tty_conf.c,v 1.16.2.1 2002/03/11 01:14:55 dd Exp $
  42  * $DragonFly: src/sys/kern/tty_conf.c,v 1.6 2006/12/23 23:47:54 swildner Exp $
  43  */
  44
  45 #include "opt_compat.h"
  46
  47 #include <sys/param.h>
  48 #include <sys/systm.h>
  49 #include <sys/tty.h>
  50 #include <sys/conf.h>
  51
  52 #ifndef MAXLDISC
  53 #define MAXLDISC 9
  54 #endif
  55
  56 static l_open_t         l_noopen;
  57 static l_close_t        l_noclose;
  58 static l_rint_t         l_norint;
  59 static l_start_t        l_nostart;
  60
  61 /*
  62  * XXX it probably doesn't matter what the entries other than the l_open
  63  * entry are here.  The l_nullioctl and ttymodem entries still look fishy.
  64  * Reconsider the removal of nullmodem anyway.  It was too much like
  65  * ttymodem, but a completely null version might be useful.
  66  */
  67 #define NODISC(n) \
  68         { l_noopen,     l_noclose,      l_noread,       l_nowrite, \
  69           l_nullioctl,  l_norint,       l_nostart,      ttymodem }
  70
  71 struct  linesw linesw[MAXLDISC] =
  72 {
  73                                 /* 0- termios */
  74         { ttyopen,      ttylclose,      ttread,         ttwrite,
  75           l_nullioctl,  ttyinput,       ttstart,        ttymodem },
  76         NODISC(1),              /* 1- defunct */
  77                                 /* 2- NTTYDISC */
  78 #ifdef COMPAT_43
  79         { ttyopen,      ttylclose,      ttread,         ttwrite,
  80           l_nullioctl,  ttyinput,       ttstart,        ttymodem },
  81 #else
  82         NODISC(2),
  83 #endif
  84         NODISC(3),              /* loadable */
  85         NODISC(4),              /* SLIPDISC */
  86         NODISC(5),              /* PPPDISC */
  87         NODISC(6),              /* NETGRAPHDISC */
  88         NODISC(7),              /* loadable */
  89         NODISC(8),              /* loadable */
  90 };
  91
  92 int     nlinesw = sizeof (linesw) / sizeof (linesw[0]);
  93
  94 static struct linesw nodisc = NODISC(0);
  95
  96 #define LOADABLE_LDISC 7
  97 /*
  98  * ldisc_register: Register a line discipline.
  99  *
 100  * discipline: Index for discipline to load, or LDISC_LOAD for us to choose.
 101  * linesw_p:   Pointer to linesw_p.
 102  *
 103  * Returns: Index used or -1 on failure.
 104  */
 105 int
 106 ldisc_register(int discipline, struct linesw *linesw_p)
 107 {
 108         int slot = -1;
 109
 110         lwkt_gettoken(&tty_token);
 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         lwkt_reltoken(&tty_token);
 126         return slot;
 127 }
 128
 129 /*
 130  * ldisc_deregister: Deregister a line discipline obtained with
 131  * ldisc_register.
 132  *
 133  * discipline: Index for discipline to unload.
 134  */
 135 void
 136 ldisc_deregister(int discipline)
 137 {
 138         lwkt_gettoken(&tty_token);
 139         if (discipline < MAXLDISC) {
 140                 linesw[discipline] = nodisc;
 141         }
 142         lwkt_reltoken(&tty_token);
 143 }
 144
 145 static int
 146 l_noopen(cdev_t dev, struct tty *tp)
 147 {
 148
 149         return (ENODEV);
 150 }
 151
 152 static int
 153 l_noclose(struct tty *tp, int flag)
 154 {
 155
 156         return (ENODEV);
 157 }
 158
 159 int
 160 l_noread(struct tty *tp, struct uio *uio, int flag)
 161 {
 162
 163         return (ENODEV);
 164 }
 165
 166 int
 167 l_nowrite(struct tty *tp, struct uio *uio, int flag)
 168 {
 169
 170         return (ENODEV);
 171 }
 172
 173 static int
 174 l_norint(int c, struct tty *tp)
 175 {
 176
 177         return (ENODEV);
 178 }
 179
 180 static int
 181 l_nostart(struct tty *tp)
 182 {
 183
 184         return (ENODEV);
 185 }
 186
 187 /*
 188  * Do nothing specific version of line
 189  * discipline specific ioctl command.
 190  */
 191 int
 192 l_nullioctl(struct tty *tp, u_long cmd, char *data, int flags,
 193             struct ucred *cred)
 194 {
 195
 196         return (ENOIOCTL);
 197 }