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tty_tty.c revision 1.10 
      1 /*	$NetBSD: tty_tty.c,v 1.10 1994/06/29 06:33:31 cgd Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1982, 1986, 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  *
     35  *	@(#)tty_tty.c	8.2 (Berkeley) 9/23/93
     36  */
     37 
     38 /*
     39  * Indirect driver for controlling tty.
     40  */
     41 #include <sys/param.h>
     42 #include <sys/systm.h>
     43 #include <sys/conf.h>
     44 #include <sys/ioctl.h>
     45 #include <sys/proc.h>
     46 #include <sys/tty.h>
     47 #include <sys/vnode.h>
     48 #include <sys/file.h>
     49 
     50 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
     51 
     52 /*ARGSUSED*/
     53 cttyopen(dev, flag, mode, p)
     54 	dev_t dev;
     55 	int flag, mode;
     56 	struct proc *p;
     57 {
     58 	struct vnode *ttyvp = cttyvp(p);
     59 	int error;
     60 
     61 	if (ttyvp == NULL)
     62 		return (ENXIO);
     63 	VOP_LOCK(ttyvp);
     64 #ifdef PARANOID
     65 	/*
     66 	 * Since group is tty and mode is 620 on most terminal lines
     67 	 * and since sessions protect terminals from processes outside
     68 	 * your session, this check is probably no longer necessary.
     69 	 * Since it inhibits setuid root programs that later switch
     70 	 * to another user from accessing /dev/tty, we have decided
     71 	 * to delete this test. (mckusick 5/93)
     72 	 */
     73 	error = VOP_ACCESS(ttyvp,
     74 	  (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
     75 	if (!error)
     76 #endif /* PARANOID */
     77 		error = VOP_OPEN(ttyvp, flag, NOCRED, p);
     78 	VOP_UNLOCK(ttyvp);
     79 	return (error);
     80 }
     81 
     82 /*ARGSUSED*/
     83 cttyread(dev, uio, flag)
     84 	dev_t dev;
     85 	struct uio *uio;
     86 	int flag;
     87 {
     88 	register struct vnode *ttyvp = cttyvp(uio->uio_procp);
     89 	int error;
     90 
     91 	if (ttyvp == NULL)
     92 		return (EIO);
     93 	VOP_LOCK(ttyvp);
     94 	error = VOP_READ(ttyvp, uio, flag, NOCRED);
     95 	VOP_UNLOCK(ttyvp);
     96 	return (error);
     97 }
     98 
     99 /*ARGSUSED*/
    100 cttywrite(dev, uio, flag)
    101 	dev_t dev;
    102 	struct uio *uio;
    103 	int flag;
    104 {
    105 	register struct vnode *ttyvp = cttyvp(uio->uio_procp);
    106 	int error;
    107 
    108 	if (ttyvp == NULL)
    109 		return (EIO);
    110 	VOP_LOCK(ttyvp);
    111 	error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
    112 	VOP_UNLOCK(ttyvp);
    113 	return (error);
    114 }
    115 
    116 /*ARGSUSED*/
    117 cttyioctl(dev, cmd, addr, flag, p)
    118 	dev_t dev;
    119 	int cmd;
    120 	caddr_t addr;
    121 	int flag;
    122 	struct proc *p;
    123 {
    124 	struct vnode *ttyvp = cttyvp(p);
    125 
    126 	if (ttyvp == NULL)
    127 		return (EIO);
    128 	if (cmd == TIOCSCTTY)		/* XXX */
    129 		return (EINVAL);
    130 	if (cmd == TIOCNOTTY) {
    131 		if (!SESS_LEADER(p)) {
    132 			p->p_flag &= ~P_CONTROLT;
    133 			return (0);
    134 		} else
    135 			return (EINVAL);
    136 	}
    137 	return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
    138 }
    139 
    140 /*ARGSUSED*/
    141 cttyselect(dev, flag, p)
    142 	dev_t dev;
    143 	int flag;
    144 	struct proc *p;
    145 {
    146 	struct vnode *ttyvp = cttyvp(p);
    147 
    148 	if (ttyvp == NULL)
    149 		return (1);	/* try operation to get EOF/failure */
    150 	return (VOP_SELECT(ttyvp, flag, FREAD|FWRITE, NOCRED, p));
    151 }
    152