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      1 /*	$NetBSD: tty_bsdpty.c,v 1.20 2014/04/04 18:11:58 christos 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 1.20 2014/04/04 18:11:58 christos Exp $");
     31 
     32 #include "opt_ptm.h"
     33 
     34 #ifndef NO_DEV_PTM
     35 #ifdef COMPAT_BSDPTY
     36 /* bsd tty implementation for pty multiplexor driver /dev/ptm{,x} */
     37 
     38 #include <sys/param.h>
     39 #include <sys/systm.h>
     40 #include <sys/ioctl.h>
     41 #include <sys/lwp.h>
     42 #include <sys/tty.h>
     43 #include <sys/stat.h>
     44 #include <sys/file.h>
     45 #include <sys/uio.h>
     46 #include <sys/kernel.h>
     47 #include <sys/vnode.h>
     48 #include <sys/namei.h>
     49 #include <sys/signalvar.h>
     50 #include <sys/filedesc.h>
     51 #include <sys/conf.h>
     52 #include <sys/poll.h>
     53 #include <sys/pty.h>
     54 #include <sys/kauth.h>
     55 
     56 /*
     57  * pts == /dev/tty[pqrs]?
     58  * ptc == /dev/pty[pqrs]?
     59  */
     60 
     61 /*
     62  * All this hard-coding is really evil.
     63  */
     64 #define TTY_GID		4
     65 #define TTY_PERM	(S_IRUSR|S_IWUSR|S_IWGRP)
     66 #define TTY_TEMPLATE	"/dev/XtyXX"
     67 #define TTY_NAMESIZE	sizeof(TTY_TEMPLATE)
     68 #define TTY_LETTERS	"pqrstuvwxyzPQRST"
     69 #define TTY_OLD_SUFFIX  "0123456789abcdef"
     70 #define TTY_NEW_SUFFIX  "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
     71 
     72 static int pty_makename(struct mount *, struct lwp *, char *, size_t, dev_t,
     73     char);
     74 static int pty_allocvp(struct mount *, struct lwp *, struct vnode **,
     75     dev_t, char);
     76 static void pty_getvattr(struct mount *, struct lwp *, struct vattr *);
     77 static int pty__getmp(struct lwp *, struct mount **);
     78 
     79 struct ptm_pty ptm_bsdpty = {
     80 	pty_allocvp,
     81 	pty_makename,
     82 	pty_getvattr,
     83 	pty__getmp,
     84 };
     85 
     86 static int
     87 /*ARGSUSED*/
     88 pty_makename(struct mount *mp, struct lwp *l, char *bf,
     89     size_t bufsiz, dev_t dev, char c)
     90 {
     91 	size_t nt;
     92 	dev_t minor = minor(dev);
     93 	const char *suffix;
     94 
     95 	if (bufsiz < TTY_NAMESIZE)
     96 		return EINVAL;
     97 
     98 	(void)memcpy(bf, TTY_TEMPLATE, TTY_NAMESIZE);
     99 
    100 	if (minor < 256) {
    101 		suffix = TTY_OLD_SUFFIX;
    102 		nt = sizeof(TTY_OLD_SUFFIX) - 1;
    103 	} else {
    104 		minor -= 256;
    105 		suffix = TTY_NEW_SUFFIX;
    106 		nt = sizeof(TTY_NEW_SUFFIX) - 1;
    107 	}
    108 
    109 	bf[5] = c;
    110 	bf[8] = TTY_LETTERS[minor / nt];
    111 	bf[9] = suffix[minor % nt];
    112 	return 0;
    113 }
    114 
    115 
    116 static int
    117 /*ARGSUSED*/
    118 pty_allocvp(struct mount *mp, struct lwp *l, struct vnode **vp, dev_t dev,
    119     char ms)
    120 {
    121 	int error;
    122 	struct pathbuf *pb;
    123 	struct nameidata nd;
    124 	char name[TTY_NAMESIZE];
    125 
    126 	error = pty_makename(NULL, l, name, sizeof(name), dev, ms);
    127 	if (error)
    128 		return error;
    129 
    130 	pb = pathbuf_create(name);
    131 	if (pb == NULL) {
    132 		return ENOMEM;
    133 	}
    134 
    135 	NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, pb);
    136 	if ((error = namei(&nd)) != 0) {
    137 		pathbuf_destroy(pb);
    138 		return error;
    139 	}
    140 	*vp = nd.ni_vp;
    141 	pathbuf_destroy(pb);
    142 	return 0;
    143 }
    144 
    145 
    146 static void
    147 /*ARGSUSED*/
    148 pty_getvattr(struct mount *mp, struct lwp *l, struct vattr *vattr)
    149 {
    150 	vattr_null(vattr);
    151 	/* get real uid */
    152 	vattr->va_uid = kauth_cred_getuid(l->l_cred);
    153 	vattr->va_gid = TTY_GID;
    154 	vattr->va_mode = TTY_PERM;
    155 }
    156 
    157 static int
    158 pty__getmp(struct lwp *l __unused, struct mount **mpp)
    159 {
    160 	*mpp = 0;
    161 	return 0;
    162 }
    163 
    164 #endif /* COMPAT_BSDPTY */
    165 #endif /* NO_DEV_PTM */
    166