xref: /freebsd/lib/libc/gen/ttyname.c (revision ca9ac06c99bfd0150b85d4d83c396ce6237c0e05)
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)
35 static char sccsid[] = "@(#)ttyname.c	8.2 (Berkeley) 1/27/94";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
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 <pthread.h>
53 #include "un-namespace.h"
54 
55 #include "libc_private.h"
56 
57 static char ttyname_buf[sizeof(_PATH_DEV) + MAXNAMLEN];
58 
59 static pthread_mutex_t	ttyname_lock = PTHREAD_MUTEX_INITIALIZER;
60 static pthread_key_t	ttyname_key;
61 static int		ttyname_init = 0;
62 
63 char *
64 ttyname_r(int fd, char *buf, size_t len)
65 {
66 	struct stat	sb;
67 	char		*rval;
68 	struct fiodgname_arg fgn;
69 
70 	rval = NULL;
71 	*buf = '\0';
72 
73 	/* Must be a terminal. */
74 	if (!isatty(fd))
75 		return (rval);
76 	/* Must be a character device. */
77 	if (_fstat(fd, &sb) || !S_ISCHR(sb.st_mode))
78 		return (rval);
79 	/* Must have enough room */
80 	if (len <= sizeof(_PATH_DEV))
81 		return (rval);
82 
83 	strcpy(buf, _PATH_DEV);
84 	fgn.len = len - strlen(buf);
85 	fgn.buf = buf + strlen(buf);
86 	if (!_ioctl(fd, FIODGNAME, &fgn))
87 		return(buf);
88 	devname_r(sb.st_rdev, S_IFCHR,
89 	    buf + strlen(buf), sizeof(buf) - strlen(buf));
90 	return (buf);
91 }
92 
93 char *
94 ttyname(int fd)
95 {
96 	char	*buf;
97 
98 	if (__isthreaded == 0)
99 		return (ttyname_r(fd, ttyname_buf, sizeof ttyname_buf));
100 
101 	if (ttyname_init == 0) {
102 		_pthread_mutex_lock(&ttyname_lock);
103 		if (ttyname_init == 0) {
104 			if (_pthread_key_create(&ttyname_key, free)) {
105 				_pthread_mutex_unlock(&ttyname_lock);
106 				return (NULL);
107 			}
108 			ttyname_init = 1;
109 		}
110 		_pthread_mutex_unlock(&ttyname_lock);
111 	}
112 
113 	/* Must have thread specific data field to put data */
114 	if ((buf = _pthread_getspecific(ttyname_key)) == NULL) {
115 		if ((buf = malloc(sizeof(_PATH_DEV) + MAXNAMLEN)) != NULL) {
116 			if (_pthread_setspecific(ttyname_key, buf) != 0) {
117 				free(buf);
118 				return (NULL);
119 			}
120 		} else {
121 			return (NULL);
122 		}
123 	}
124 	return (ttyname_r(fd, buf, sizeof(_PATH_DEV) + MAXNAMLEN));
125 }
126 
127