1/*	$NetBSD: ttyname.c,v 1.25 2012/06/03 21:42:46 joerg Exp $	*/
2
3/*
4 * Copyright (c) 1988, 1993
5 *	The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33#if defined(LIBC_SCCS) && !defined(lint)
34#if 0
35static char sccsid[] = "@(#)ttyname.c	8.2 (Berkeley) 1/27/94";
36#else
37__RCSID("$NetBSD: ttyname.c,v 1.25 2012/06/03 21:42:46 joerg Exp $");
38#endif
39#endif /* LIBC_SCCS and not lint */
40
41#include "namespace.h"
42#include <sys/ioctl.h>
43#include <sys/stat.h>
44
45#include <assert.h>
46#include <errno.h>
47#include <limits.h>
48#include <paths.h>
49#include <string.h>
50#include <stdlib.h>
51#include <termios.h>
52#include <unistd.h>
53
54#ifdef __weak_alias
55__weak_alias(ttyname,_ttyname)
56__weak_alias(ttyname_r,_ttyname_r)
57#endif
58
59int
60ttyname_r(int fd, char *buf, size_t len)
61{
62	struct stat sb;
63	struct termios ttyb;
64	struct ptmget ptm;
65
66	_DIAGASSERT(fd != -1);
67
68	/* If it is a pty, deal with it quickly */
69	if (ioctl(fd, TIOCPTSNAME, &ptm) != -1) {
70		if (strlcpy(buf, ptm.sn, len) >= len) {
71			return ERANGE;
72		}
73		return 0;
74	}
75
76	/* Must be a terminal. */
77	if (tcgetattr(fd, &ttyb) == -1)
78		return errno;
79
80	if (fstat(fd, &sb))
81		return errno;
82
83	if (strlcpy(buf, _PATH_DEV, len) >= len)
84		return ERANGE;
85	buf += strlen(_PATH_DEV);
86	len -= strlen(_PATH_DEV);
87	return devname_r(sb.st_rdev, sb.st_mode & S_IFMT, buf, len);
88}
89
90char *
91ttyname(int fd)
92{
93	static char buf[PATH_MAX];
94	int rv;
95
96	rv = ttyname_r(fd, buf, sizeof(buf));
97	if (rv != 0) {
98		errno = rv;
99		return NULL;
100	}
101	return buf;
102}
103