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tty_bsdpty.c revision 1.9 
      1 /*	$NetBSD: tty_bsdpty.c,v 1.9 2006/07/23 22:06:11 ad Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2004 The NetBSD Foundation, Inc.
      5  * 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 NetBSD
     18  *        Foundation, Inc. and its contributors.
     19  * 4. Neither the name of The NetBSD Foundation nor the names of its
     20  *    contributors may be used to endorse or promote products derived
     21  *    from this software without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     25  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     26  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     27  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     28  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     29  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     30  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     33  * POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 __KERNEL_RCSID(0, "$NetBSD: tty_bsdpty.c,v 1.9 2006/07/23 22:06:11 ad Exp $");
     38 
     39 #include "opt_ptm.h"
     40 
     41 #ifdef COMPAT_BSDPTY
     42 /* bsd tty implementation for pty multiplexor driver /dev/ptm{,x} */
     43 
     44 #include <sys/param.h>
     45 #include <sys/systm.h>
     46 #include <sys/ioctl.h>
     47 #include <sys/lwp.h>
     48 #include <sys/tty.h>
     49 #include <sys/stat.h>
     50 #include <sys/file.h>
     51 #include <sys/uio.h>
     52 #include <sys/kernel.h>
     53 #include <sys/vnode.h>
     54 #include <sys/namei.h>
     55 #include <sys/signalvar.h>
     56 #include <sys/uio.h>
     57 #include <sys/filedesc.h>
     58 #include <sys/conf.h>
     59 #include <sys/poll.h>
     60 #include <sys/malloc.h>
     61 #include <sys/pty.h>
     62 #include <sys/kauth.h>
     63 
     64 /*
     65  * pts == /dev/tty[pqrs]?
     66  * ptc == /dev/pty[pqrs]?
     67  */
     68 
     69 /*
     70  * All this hard-coding is really evil.
     71  */
     72 #define TTY_GID		4
     73 #define TTY_PERM	(S_IRUSR|S_IWUSR|S_IWGRP)
     74 #define TTY_TEMPLATE	"/dev/XtyXX"
     75 #define TTY_NAMESIZE	sizeof(TTY_TEMPLATE)
     76 #define TTY_LETTERS	"pqrstuvwxyzPQRST"
     77 #define TTY_OLD_SUFFIX  "0123456789abcdef"
     78 #define TTY_NEW_SUFFIX  "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
     79 
     80 static int pty_makename(struct ptm_pty *, struct lwp *, char *, size_t, dev_t,
     81     char);
     82 static int pty_allocvp(struct ptm_pty *, struct lwp *, struct vnode **,
     83     dev_t, char);
     84 static void pty_getvattr(struct ptm_pty *, struct lwp *, struct vattr *);
     85 
     86 struct ptm_pty ptm_bsdpty = {
     87 	pty_allocvp,
     88 	pty_makename,
     89 	pty_getvattr,
     90 	NULL
     91 };
     92 
     93 static int
     94 /*ARGSUSED*/
     95 pty_makename(struct ptm_pty *ptm, struct lwp *l, char *bf, size_t bufsiz,
     96     dev_t dev, char c)
     97 {
     98 	size_t nt;
     99 	dev_t minor = minor(dev);
    100 	const char *suffix;
    101 
    102 	if (bufsiz < TTY_NAMESIZE)
    103 		return EINVAL;
    104 
    105 	(void)memcpy(bf, TTY_TEMPLATE, TTY_NAMESIZE);
    106 
    107 	if (minor < 256) {
    108 		suffix = TTY_OLD_SUFFIX;
    109 		nt = sizeof(TTY_OLD_SUFFIX) - 1;
    110 	} else {
    111 		minor -= 256;
    112 		suffix = TTY_NEW_SUFFIX;
    113 		nt = sizeof(TTY_NEW_SUFFIX) - 1;
    114 	}
    115 
    116 	bf[5] = c;
    117 	bf[8] = TTY_LETTERS[minor / nt];
    118 	bf[9] = suffix[minor % nt];
    119 	return 0;
    120 }
    121 
    122 
    123 static int
    124 /*ARGSUSED*/
    125 pty_allocvp(struct ptm_pty *ptm, struct lwp *l, struct vnode **vp, dev_t dev,
    126     char ms)
    127 {
    128 	int error;
    129 	struct nameidata nd;
    130 	char name[TTY_NAMESIZE];
    131 
    132 	error = (*ptm->makename)(ptm, l, name, sizeof(name), dev, ms);
    133 	if (error)
    134 		return error;
    135 
    136 	NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE, name, l);
    137 	if ((error = namei(&nd)) != 0)
    138 		return error;
    139 	*vp = nd.ni_vp;
    140 	return 0;
    141 }
    142 
    143 
    144 static void
    145 /*ARGSUSED*/
    146 pty_getvattr(struct ptm_pty *ptm, struct lwp *l, struct vattr *vattr)
    147 {
    148 	VATTR_NULL(vattr);
    149 	/* get real uid */
    150 	vattr->va_uid = kauth_cred_getuid(l->l_cred);
    151 	vattr->va_gid = TTY_GID;
    152 	vattr->va_mode = TTY_PERM;
    153 }
    154 #endif
    155