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tty_tty.c revision 1.9 
      1 /*-
      2  * Copyright (c) 1982, 1986, 1991, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  *
     33  *	from: @(#)tty_tty.c	8.2 (Berkeley) 9/23/93
     34  *	$Id: tty_tty.c,v 1.9 1994/05/12 03:48:37 cgd Exp $
     35  */
     36 
     37 /*
     38  * Indirect driver for controlling tty.
     39  */
     40 #include <sys/param.h>
     41 #include <sys/systm.h>
     42 #include <sys/conf.h>
     43 #include <sys/ioctl.h>
     44 #include <sys/proc.h>
     45 #include <sys/tty.h>
     46 #include <sys/vnode.h>
     47 #include <sys/file.h>
     48 
     49 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
     50 
     51 /*ARGSUSED*/
     52 cttyopen(dev, flag, mode, p)
     53 	dev_t dev;
     54 	int flag, mode;
     55 	struct proc *p;
     56 {
     57 	struct vnode *ttyvp = cttyvp(p);
     58 	int error;
     59 
     60 	if (ttyvp == NULL)
     61 		return (ENXIO);
     62 	VOP_LOCK(ttyvp);
     63 #ifdef PARANOID
     64 	/*
     65 	 * Since group is tty and mode is 620 on most terminal lines
     66 	 * and since sessions protect terminals from processes outside
     67 	 * your session, this check is probably no longer necessary.
     68 	 * Since it inhibits setuid root programs that later switch
     69 	 * to another user from accessing /dev/tty, we have decided
     70 	 * to delete this test. (mckusick 5/93)
     71 	 */
     72 	error = VOP_ACCESS(ttyvp,
     73 	  (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
     74 	if (!error)
     75 #endif /* PARANOID */
     76 		error = VOP_OPEN(ttyvp, flag, NOCRED, p);
     77 	VOP_UNLOCK(ttyvp);
     78 	return (error);
     79 }
     80 
     81 /*ARGSUSED*/
     82 cttyread(dev, uio, flag)
     83 	dev_t dev;
     84 	struct uio *uio;
     85 	int flag;
     86 {
     87 	register struct vnode *ttyvp = cttyvp(uio->uio_procp);
     88 	int error;
     89 
     90 	if (ttyvp == NULL)
     91 		return (EIO);
     92 	VOP_LOCK(ttyvp);
     93 	error = VOP_READ(ttyvp, uio, flag, NOCRED);
     94 	VOP_UNLOCK(ttyvp);
     95 	return (error);
     96 }
     97 
     98 /*ARGSUSED*/
     99 cttywrite(dev, uio, flag)
    100 	dev_t dev;
    101 	struct uio *uio;
    102 	int flag;
    103 {
    104 	register struct vnode *ttyvp = cttyvp(uio->uio_procp);
    105 	int error;
    106 
    107 	if (ttyvp == NULL)
    108 		return (EIO);
    109 	VOP_LOCK(ttyvp);
    110 	error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
    111 	VOP_UNLOCK(ttyvp);
    112 	return (error);
    113 }
    114 
    115 /*ARGSUSED*/
    116 cttyioctl(dev, cmd, addr, flag, p)
    117 	dev_t dev;
    118 	int cmd;
    119 	caddr_t addr;
    120 	int flag;
    121 	struct proc *p;
    122 {
    123 	struct vnode *ttyvp = cttyvp(p);
    124 
    125 	if (ttyvp == NULL)
    126 		return (EIO);
    127 	if (cmd == TIOCSCTTY)		/* XXX */
    128 		return (EINVAL);
    129 	if (cmd == TIOCNOTTY) {
    130 		if (!SESS_LEADER(p)) {
    131 			p->p_flag &= ~P_CONTROLT;
    132 			return (0);
    133 		} else
    134 			return (EINVAL);
    135 	}
    136 	return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
    137 }
    138 
    139 /*ARGSUSED*/
    140 cttyselect(dev, flag, p)
    141 	dev_t dev;
    142 	int flag;
    143 	struct proc *p;
    144 {
    145 	struct vnode *ttyvp = cttyvp(p);
    146 
    147 	if (ttyvp == NULL)
    148 		return (1);	/* try operation to get EOF/failure */
    149 	return (VOP_SELECT(ttyvp, flag, FREAD|FWRITE, NOCRED, p));
    150 }
    151