xref: /freebsd/lib/libc/gen/ttyname.c (revision 17ee9d00bc1ae1e598c38f25826f861e4bc6c3ce)
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 
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 #include <fcntl.h>
41 #include <dirent.h>
42 #include <sgtty.h>
43 #include <db.h>
44 #include <string.h>
45 #include <paths.h>
46 
47 static char buf[sizeof(_PATH_DEV) + MAXNAMLEN] = _PATH_DEV;
48 static char *oldttyname __P((int, struct stat *));
49 
50 char *
51 ttyname(fd)
52 	int fd;
53 {
54 	struct stat sb;
55 	struct sgttyb ttyb;
56 	DB *db;
57 	DBT data, key;
58 	struct {
59 		mode_t type;
60 		dev_t dev;
61 	} bkey;
62 
63 	/* Must be a terminal. */
64 	if (ioctl(fd, TIOCGETP, &ttyb) < 0)
65 		return (NULL);
66 	/* Must be a character device. */
67 	if (fstat(fd, &sb) || !S_ISCHR(sb.st_mode))
68 		return (NULL);
69 
70 	if (db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL)) {
71 		memset(&bkey, 0, sizeof(bkey));
72 		bkey.type = S_IFCHR;
73 		bkey.dev = sb.st_rdev;
74 		key.data = &bkey;
75 		key.size = sizeof(bkey);
76 		if (!(db->get)(db, &key, &data, 0)) {
77 			bcopy(data.data,
78 			    buf + sizeof(_PATH_DEV) - 1, data.size);
79 			(void)(db->close)(db);
80 			return (buf);
81 		}
82 		(void)(db->close)(db);
83 	}
84 	return (oldttyname(fd, &sb));
85 }
86 
87 static char *
88 oldttyname(fd, sb)
89 	int fd;
90 	struct stat *sb;
91 {
92 	register struct dirent *dirp;
93 	register DIR *dp;
94 	struct stat dsb;
95 
96 	if ((dp = opendir(_PATH_DEV)) == NULL)
97 		return (NULL);
98 
99 	while (dirp = readdir(dp)) {
100 		if (dirp->d_fileno != sb->st_ino)
101 			continue;
102 		bcopy(dirp->d_name, buf + sizeof(_PATH_DEV) - 1,
103 		    dirp->d_namlen + 1);
104 		if (stat(buf, &dsb) || sb->st_dev != dsb.st_dev ||
105 		    sb->st_ino != dsb.st_ino)
106 			continue;
107 		(void)closedir(dp);
108 		return (buf);
109 	}
110 	(void)closedir(dp);
111 	return (NULL);
112 }
113