bsd/kern/tty_conf.c

   1 /*
   2  * Copyright (c) 1997-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*-
  29  * Copyright (c) 1982, 1986, 1991, 1993
  30  *      The Regents of the University of California.  All rights reserved.
  31  * (c) UNIX System Laboratories, Inc.
  32  * All or some portions of this file are derived from material licensed
  33  * to the University of California by American Telephone and Telegraph
  34  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  35  * the permission of UNIX System Laboratories, Inc.
  36  *
  37  * Redistribution and use in source and binary forms, with or without
  38  * modification, are permitted provided that the following conditions
  39  * are met:
  40  * 1. Redistributions of source code must retain the above copyright
  41  *    notice, this list of conditions and the following disclaimer.
  42  * 2. Redistributions in binary form must reproduce the above copyright
  43  *    notice, this list of conditions and the following disclaimer in the
  44  *    documentation and/or other materials provided with the distribution.
  45  * 3. All advertising materials mentioning features or use of this software
  46  *    must display the following acknowledgement:
  47  *      This product includes software developed by the University of
  48  *      California, Berkeley and its contributors.
  49  * 4. Neither the name of the University nor the names of its contributors
  50  *    may be used to endorse or promote products derived from this software
  51  *    without specific prior written permission.
  52  *
  53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  63  * SUCH DAMAGE.
  64  *
  65  *      @(#)tty_conf.c  8.4 (Berkeley) 1/21/94
  66  */
  67
  68 #include <sys/param.h>
  69 #include <sys/systm.h>
  70 #include <sys/tty.h>
  71 #include <sys/conf.h>
  72
  73 #ifndef MAXLDISC
  74 #define MAXLDISC 8
  75 #endif
  76
  77 #define l_noopen        ((l_open_t *)  &enodev)
  78 #define l_noclose       ((l_close_t *) &enodev)
  79 #define l_noread        ((l_read_t *)  &enodev)
  80 #define l_nowrite       ((l_write_t *) &enodev)
  81 #define l_norint        ((l_rint_t *)  &enodev)
  82
  83 static l_ioctl_t        l_noioctl;
  84 static l_start_t        l_nostart;
  85
  86 /*
  87  * XXX it probably doesn't matter what the entries other than the l_open
  88  * entry are here.  The l_noioctl and ttymodem entries still look fishy.
  89  * Reconsider the removal of nullmodem anyway.  It was too much like
  90  * ttymodem, but a completely null version might be useful.
  91  */
  92 #define NODISC(n) \
  93         { l_noopen,     l_noclose,      l_noread,       l_nowrite, \
  94           l_noioctl,    l_norint,       l_nostart,      ttymodem }
  95
  96 struct  linesw linesw[MAXLDISC] =
  97 {
  98                                 /* 0- termios */
  99         { ttyopen,      ttylclose,      ttread,         ttwrite,
 100           l_noioctl,    ttyinput,       ttwwakeup,      ttymodem },
 101         NODISC(1),              /* 1- defunct */
 102                                 /* 2- NTTYDISC */
 103         { ttyopen,      ttylclose,      ttread,         ttwrite,
 104           l_noioctl,    ttyinput,       ttwwakeup,      ttymodem },
 105         NODISC(3),              /* TABLDISC */
 106         NODISC(4),              /* SLIPDISC */
 107         NODISC(5),              /* PPPDISC */
 108         NODISC(6),              /* loadable */
 109         NODISC(7),              /* loadable */
 110 };
 111
 112 const int nlinesw = sizeof (linesw) / sizeof (linesw[0]);
 113
 114 static struct linesw nodisc = NODISC(0);
 115
 116 #define LOADABLE_LDISC 6
 117 /*
 118  * ldisc_register: Register a line discipline.
 119  *
 120  * discipline: Index for discipline to load, or LDISC_LOAD for us to choose.
 121  * linesw_p:   Pointer to linesw_p.
 122  *
 123  * Returns: Index used or -1 on failure.
 124  */
 125 int
 126 ldisc_register(int discipline, struct linesw *linesw_p)
 127 {
 128         int slot = -1;
 129
 130         if (discipline == LDISC_LOAD) {
 131                 int i;
 132                 for (i = LOADABLE_LDISC; i < MAXLDISC; i++)
 133                         if (bcmp(linesw + i, &nodisc, sizeof(nodisc)) == 0) {
 134                                 slot = i;
 135                         }
 136         }
 137         else if (discipline >= 0 && discipline < MAXLDISC) {
 138                 slot = discipline;
 139         }
 140
 141         if (slot != -1 && linesw_p)
 142                 linesw[slot] = *linesw_p;
 143
 144         return slot;
 145 }
 146
 147 /*
 148  * ldisc_deregister: Deregister a line discipline obtained with
 149  * ldisc_register.  Can only deregister "loadable" ones now.
 150  *
 151  * discipline: Index for discipline to unload.
 152  */
 153 void
 154 ldisc_deregister(int discipline)
 155 {
 156         if (discipline >= LOADABLE_LDISC && discipline < MAXLDISC) {
 157                 linesw[discipline] = nodisc;
 158         }
 159 }
 160
 161 /*
 162  * Do nothing specific version of line
 163  * discipline specific ioctl command.
 164  */
 165 static int
 166 l_noioctl(__unused struct tty *tp, __unused u_long cmd, __unused caddr_t data,
 167           __unused int flags, __unused struct proc *p)
 168 {
 169         return ENOTTY;
 170 }
 171
 172 static void
 173 l_nostart(__unused struct tty *tp)
 174 {
 175 }