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tty_tty.c revision 1.1.1.2 
      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  *	@(#)tty_tty.c	8.2 (Berkeley) 9/23/93
     34  */
     35 
     36 /*
     37  * Indirect driver for controlling tty.
     38  */
     39 #include <sys/param.h>
     40 #include <sys/systm.h>
     41 #include <sys/conf.h>
     42 #include <sys/ioctl.h>
     43 #include <sys/proc.h>
     44 #include <sys/tty.h>
     45 #include <sys/vnode.h>
     46 #include <sys/file.h>
     47 
     48 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
     49 
     50 /*ARGSUSED*/
     51 cttyopen(dev, flag, mode, p)
     52 	dev_t dev;
     53 	int flag, mode;
     54 	struct proc *p;
     55 {
     56 	struct vnode *ttyvp = cttyvp(p);
     57 	int error;
     58 
     59 	if (ttyvp == NULL)
     60 		return (ENXIO);
     61 	VOP_LOCK(ttyvp);
     62 #ifdef PARANOID
     63 	/*
     64 	 * Since group is tty and mode is 620 on most terminal lines
     65 	 * and since sessions protect terminals from processes outside
     66 	 * your session, this check is probably no longer necessary.
     67 	 * Since it inhibits setuid root programs that later switch
     68 	 * to another user from accessing /dev/tty, we have decided
     69 	 * to delete this test. (mckusick 5/93)
     70 	 */
     71 	error = VOP_ACCESS(ttyvp,
     72 	  (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
     73 	if (!error)
     74 #endif /* PARANOID */
     75 		error = VOP_OPEN(ttyvp, flag, NOCRED, p);
     76 	VOP_UNLOCK(ttyvp);
     77 	return (error);
     78 }
     79 
     80 /*ARGSUSED*/
     81 cttyread(dev, uio, flag)
     82 	dev_t dev;
     83 	struct uio *uio;
     84 	int flag;
     85 {
     86 	register struct vnode *ttyvp = cttyvp(uio->uio_procp);
     87 	int error;
     88 
     89 	if (ttyvp == NULL)
     90 		return (EIO);
     91 	VOP_LOCK(ttyvp);
     92 	error = VOP_READ(ttyvp, uio, flag, NOCRED);
     93 	VOP_UNLOCK(ttyvp);
     94 	return (error);
     95 }
     96 
     97 /*ARGSUSED*/
     98 cttywrite(dev, uio, flag)
     99 	dev_t dev;
    100 	struct uio *uio;
    101 	int flag;
    102 {
    103 	register struct vnode *ttyvp = cttyvp(uio->uio_procp);
    104 	int error;
    105 
    106 	if (ttyvp == NULL)
    107 		return (EIO);
    108 	VOP_LOCK(ttyvp);
    109 	error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
    110 	VOP_UNLOCK(ttyvp);
    111 	return (error);
    112 }
    113 
    114 /*ARGSUSED*/
    115 cttyioctl(dev, cmd, addr, flag, p)
    116 	dev_t dev;
    117 	int cmd;
    118 	caddr_t addr;
    119 	int flag;
    120 	struct proc *p;
    121 {
    122 	struct vnode *ttyvp = cttyvp(p);
    123 
    124 	if (ttyvp == NULL)
    125 		return (EIO);
    126 	if (cmd == TIOCNOTTY) {
    127 		if (!SESS_LEADER(p)) {
    128 			p->p_flag &= ~P_CONTROLT;
    129 			return (0);
    130 		} else
    131 			return (EINVAL);
    132 	}
    133 	return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
    134 }
    135 
    136 /*ARGSUSED*/
    137 cttyselect(dev, flag, p)
    138 	dev_t dev;
    139 	int flag;
    140 	struct proc *p;
    141 {
    142 	struct vnode *ttyvp = cttyvp(p);
    143 
    144 	if (ttyvp == NULL)
    145 		return (1);	/* try operation to get EOF/failure */
    146 	return (VOP_SELECT(ttyvp, flag, FREAD|FWRITE, NOCRED, p));
    147 }
    148