ttyname.c revision 10954 
1234285Sdim/*
2234285Sdim * Copyright (c) 1988, 1993
3234285Sdim *	The Regents of the University of California.  All rights reserved.
4234285Sdim *
5234285Sdim * Redistribution and use in source and binary forms, with or without
6234285Sdim * modification, are permitted provided that the following conditions
7234285Sdim * are met:
8234285Sdim * 1. Redistributions of source code must retain the above copyright
9234285Sdim *    notice, this list of conditions and the following disclaimer.
10234285Sdim * 2. Redistributions in binary form must reproduce the above copyright
11234285Sdim *    notice, this list of conditions and the following disclaimer in the
12234285Sdim *    documentation and/or other materials provided with the distribution.
13234285Sdim * 3. All advertising materials mentioning features or use of this software
14234285Sdim *    must display the following acknowledgement:
15234285Sdim *	This product includes software developed by the University of
16234285Sdim *	California, Berkeley and its contributors.
17234285Sdim * 4. Neither the name of the University nor the names of its contributors
18234285Sdim *    may be used to endorse or promote products derived from this software
19234285Sdim *    without specific prior written permission.
20234285Sdim *
21234285Sdim * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22234285Sdim * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23234285Sdim * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24234285Sdim * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25234285Sdim * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26234285Sdim * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27234285Sdim * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28234285Sdim * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29234285Sdim * 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
38#include <sys/types.h>
39#include <sys/stat.h>
40#include <fcntl.h>
41#include <dirent.h>
42#include <termios.h>
43#include <db.h>
44#include <string.h>
45#include <paths.h>
46
47static char buf[sizeof(_PATH_DEV) + MAXNAMLEN] = _PATH_DEV;
48static char *oldttyname __P((int, struct stat *));
49
50char *
51ttyname(fd)
52	int fd;
53{
54	struct stat sb;
55	struct termios 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 (tcgetattr(fd, &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
87static char *
88oldttyname(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