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tty_bsdpty.c revision 1.17 
      1 /*	$NetBSD: tty_bsdpty.c,v 1.17 2010/11/19 06:44:43 dholland 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  *
     16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: tty_bsdpty.c,v 1.17 2010/11/19 06:44:43 dholland Exp $");
     31 
     32 #include "opt_ptm.h"
     33 
     34 #ifdef COMPAT_BSDPTY
     35 /* bsd tty implementation for pty multiplexor driver /dev/ptm{,x} */
     36 
     37 #include <sys/param.h>
     38 #include <sys/systm.h>
     39 #include <sys/ioctl.h>
     40 #include <sys/lwp.h>
     41 #include <sys/tty.h>
     42 #include <sys/stat.h>
     43 #include <sys/file.h>
     44 #include <sys/uio.h>
     45 #include <sys/kernel.h>
     46 #include <sys/vnode.h>
     47 #include <sys/namei.h>
     48 #include <sys/signalvar.h>
     49 #include <sys/filedesc.h>
     50 #include <sys/conf.h>
     51 #include <sys/poll.h>
     52 #include <sys/pty.h>
     53 #include <sys/kauth.h>
     54 
     55 /*
     56  * pts == /dev/tty[pqrs]?
     57  * ptc == /dev/pty[pqrs]?
     58  */
     59 
     60 /*
     61  * All this hard-coding is really evil.
     62  */
     63 #define TTY_GID		4
     64 #define TTY_PERM	(S_IRUSR|S_IWUSR|S_IWGRP)
     65 #define TTY_TEMPLATE	"/dev/XtyXX"
     66 #define TTY_NAMESIZE	sizeof(TTY_TEMPLATE)
     67 #define TTY_LETTERS	"pqrstuvwxyzPQRST"
     68 #define TTY_OLD_SUFFIX  "0123456789abcdef"
     69 #define TTY_NEW_SUFFIX  "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
     70 
     71 static int pty_makename(struct ptm_pty *, struct lwp *, char *, size_t, dev_t,
     72     char);
     73 static int pty_allocvp(struct ptm_pty *, struct lwp *, struct vnode **,
     74     dev_t, char);
     75 static void pty_getvattr(struct ptm_pty *, struct lwp *, struct vattr *);
     76 
     77 struct ptm_pty ptm_bsdpty = {
     78 	pty_allocvp,
     79 	pty_makename,
     80 	pty_getvattr,
     81 	NULL
     82 };
     83 
     84 static int
     85 /*ARGSUSED*/
     86 pty_makename(struct ptm_pty *ptm, struct lwp *l, char *bf,
     87     size_t bufsiz, dev_t dev, char c)
     88 {
     89 	size_t nt;
     90 	dev_t minor = minor(dev);
     91 	const char *suffix;
     92 
     93 	if (bufsiz < TTY_NAMESIZE)
     94 		return EINVAL;
     95 
     96 	(void)memcpy(bf, TTY_TEMPLATE, TTY_NAMESIZE);
     97 
     98 	if (minor < 256) {
     99 		suffix = TTY_OLD_SUFFIX;
    100 		nt = sizeof(TTY_OLD_SUFFIX) - 1;
    101 	} else {
    102 		minor -= 256;
    103 		suffix = TTY_NEW_SUFFIX;
    104 		nt = sizeof(TTY_NEW_SUFFIX) - 1;
    105 	}
    106 
    107 	bf[5] = c;
    108 	bf[8] = TTY_LETTERS[minor / nt];
    109 	bf[9] = suffix[minor % nt];
    110 	return 0;
    111 }
    112 
    113 
    114 static int
    115 /*ARGSUSED*/
    116 pty_allocvp(struct ptm_pty *ptm, struct lwp *l, struct vnode **vp, dev_t dev,
    117     char ms)
    118 {
    119 	int error;
    120 	struct pathbuf *pb;
    121 	struct nameidata nd;
    122 	char name[TTY_NAMESIZE];
    123 
    124 	error = (*ptm->makename)(ptm, l, name, sizeof(name), dev, ms);
    125 	if (error)
    126 		return error;
    127 
    128 	pb = pathbuf_create(name);
    129 	if (pb == NULL) {
    130 		return ENOMEM;
    131 	}
    132 
    133 	NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, pb);
    134 	if ((error = namei(&nd)) != 0) {
    135 		pathbuf_destroy(pb);
    136 		return error;
    137 	}
    138 	*vp = nd.ni_vp;
    139 	pathbuf_destroy(pb);
    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