ttyname.c revision 146455 
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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if defined(LIBC_SCCS) && !defined(lint)
35static char sccsid[] = "@(#)ttyname.c	8.2 (Berkeley) 1/27/94";
36#endif /* LIBC_SCCS and not lint */
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD: head/lib/libc/gen/ttyname.c 146455 2005-05-20 15:39:20Z ume $");
39
40#include "namespace.h"
41#include <sys/types.h>
42#include <sys/stat.h>
43#include <sys/ioctl.h>
44#include <sys/filio.h>
45#include <fcntl.h>
46#include <dirent.h>
47#include <stdlib.h>
48#include <termios.h>
49#include <unistd.h>
50#include <string.h>
51#include <paths.h>
52#include <errno.h>
53#include "reentrant.h"
54#include "un-namespace.h"
55
56#include "libc_private.h"
57
58static char ttyname_buf[sizeof(_PATH_DEV) + MAXNAMLEN];
59
60static once_t		ttyname_init_once = ONCE_INITIALIZER;
61static thread_key_t	ttyname_key;
62static int		ttyname_keycreated = 0;
63
64int
65ttyname_r(int fd, char *buf, size_t len)
66{
67	struct stat	sb;
68	struct fiodgname_arg fgn;
69	size_t used;
70
71	*buf = '\0';
72
73	/* Must be a terminal. */
74	if (!isatty(fd))
75		return (ENOTTY);
76	/* Must be a character device. */
77	if (_fstat(fd, &sb) || !S_ISCHR(sb.st_mode))
78		return (ENOTTY);
79	/* Must have enough room */
80	if (len <= sizeof(_PATH_DEV))
81		return (ERANGE);
82
83	strcpy(buf, _PATH_DEV);
84	used = strlen(buf);
85	fgn.len = len - used;
86	fgn.buf = buf + used;
87	if (!_ioctl(fd, FIODGNAME, &fgn))
88		return (0);
89	used = strlen(buf);
90	devname_r(sb.st_rdev, S_IFCHR, buf + used, len - used);
91	return (0);
92}
93
94static void
95ttyname_keycreate(void)
96{
97	ttyname_keycreated = (thr_keycreate(&ttyname_key, free) == 0);
98}
99
100char *
101ttyname(int fd)
102{
103	char	*buf;
104
105	if (thr_main() != 0)
106		buf = ttyname_buf;
107	else {
108		if (thr_once(&ttyname_init_once, ttyname_keycreate) != 0 ||
109		    !ttyname_keycreated)
110			return (NULL);
111		if ((buf = thr_getspecific(ttyname_key)) == NULL) {
112			if ((buf = malloc(sizeof ttyname_buf)) == NULL)
113				return (NULL);
114			if (thr_setspecific(ttyname_key, buf) != 0) {
115				free(buf);
116				return (NULL);
117			}
118		}
119	}
120
121	if (ttyname_r(fd, buf, sizeof ttyname_buf) != 0)
122		return (NULL);
123	return (buf);
124}
125