1/*
2 * Copyright (c) 1988, 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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)ttyname.c	8.2 (Berkeley) 1/27/94";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD$");
35
36#include "namespace.h"
37#include <sys/types.h>
38#include <sys/ioctl.h>
39#include <sys/filio.h>
40#include <fcntl.h>
41#include <dirent.h>
42#include <stdlib.h>
43#include <termios.h>
44#include <unistd.h>
45#include <string.h>
46#include <paths.h>
47#include <errno.h>
48#include "reentrant.h"
49#include "un-namespace.h"
50
51#include "libc_private.h"
52
53static char ttyname_buf[sizeof(_PATH_DEV) + MAXNAMLEN];
54
55static once_t		ttyname_init_once = ONCE_INITIALIZER;
56static thread_key_t	ttyname_key;
57static int		ttyname_keycreated = 0;
58
59int
60ttyname_r(int fd, char *buf, size_t len)
61{
62	size_t used;
63
64	*buf = '\0';
65
66	/* Must be a terminal. */
67	if (!isatty(fd))
68		return (ENOTTY);
69	/* Must have enough room */
70	if (len <= sizeof(_PATH_DEV))
71		return (ERANGE);
72
73	strcpy(buf, _PATH_DEV);
74	used = strlen(buf);
75	if (fdevname_r(fd, buf + used, len - used) == NULL)
76		return (ENOTTY);
77	return (0);
78}
79
80static void
81ttyname_keycreate(void)
82{
83	ttyname_keycreated = (thr_keycreate(&ttyname_key, free) == 0);
84}
85
86char *
87ttyname(int fd)
88{
89	char	*buf;
90
91	if (thr_main() != 0)
92		buf = ttyname_buf;
93	else {
94		if (thr_once(&ttyname_init_once, ttyname_keycreate) != 0 ||
95		    !ttyname_keycreated)
96			return (NULL);
97		if ((buf = thr_getspecific(ttyname_key)) == NULL) {
98			if ((buf = malloc(sizeof ttyname_buf)) == NULL)
99				return (NULL);
100			if (thr_setspecific(ttyname_key, buf) != 0) {
101				free(buf);
102				return (NULL);
103			}
104		}
105	}
106
107	if (ttyname_r(fd, buf, sizeof ttyname_buf) != 0)
108		return (NULL);
109	return (buf);
110}
111