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devname.c revision 1.5 
      1 /*	$NetBSD: devname.c,v 1.5 1997/07/13 18:54:19 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1989, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)devname.c	8.1 (Berkeley) 6/4/93";
     40 #else
     41 __RCSID("$NetBSD: devname.c,v 1.5 1997/07/13 18:54:19 christos Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include "namespace.h"
     46 #include <sys/types.h>
     47 
     48 #include <db.h>
     49 #include <errno.h>
     50 #include <fcntl.h>
     51 #include <paths.h>
     52 #include <stdio.h>
     53 #include <string.h>
     54 #include <stdlib.h>
     55 #include <err.h>
     56 
     57 char *
     58 devname(dev, type)
     59 	dev_t dev;
     60 	mode_t type;
     61 {
     62 	struct {
     63 		mode_t type;
     64 		dev_t dev;
     65 	} bkey;
     66 	static DB *db;
     67 	static int failure;
     68 	DBT data, key;
     69 
     70 	if (!db && !failure &&
     71 	    !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
     72 		warn("warning: %s", _PATH_DEVDB);
     73 		failure = 1;
     74 	}
     75 	if (failure)
     76 		return ("??");
     77 
     78 	/*
     79 	 * Keys are a mode_t followed by a dev_t.  The former is the type of
     80 	 * the file (mode & S_IFMT), the latter is the st_rdev field.  Be
     81 	 * sure to clear any padding that may be found in bkey.
     82 	 */
     83 	memset(&bkey, 0, sizeof(bkey));
     84 	bkey.dev = dev;
     85 	bkey.type = type;
     86 	key.data = &bkey;
     87 	key.size = sizeof(bkey);
     88 	return ((db->get)(db, &key, &data, 0) ? "??" : (char *)data.data);
     89 }
     90