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ttyname.c revision 1.1.1.2 
      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