xref: /openbsd-src/lib/libc/gen/devname.c (revision db3296cf5c1dd9058ceecc3a29fe4aaa0bd26000)
1 /*
2  * Copyright (c) 1989, 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. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char rcsid[] = "$OpenBSD: devname.c,v 1.5 2003/07/15 17:32:41 deraadt Exp $";
32 #endif /* LIBC_SCCS and not lint */
33 
34 #include <sys/types.h>
35 
36 #include <db.h>
37 #include <err.h>
38 #include <errno.h>
39 #include <fcntl.h>
40 #include <paths.h>
41 #include <stdio.h>
42 #include <string.h>
43 #include <stdlib.h>
44 
45 char *
46 devname(int dev, int t)
47 {
48 	mode_t type = t;
49 	struct {
50 		mode_t type;
51 		dev_t dev;
52 	} bkey;
53 	static DB *db;
54 	static int failure;
55 	DBT data, key;
56 
57 	if (!db && !failure &&
58 	    !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
59 		_warn("warning: %s", _PATH_DEVDB);
60 		failure = 1;
61 	}
62 	if (failure)
63 		return ("??");
64 
65 	/*
66 	 * Keys are a mode_t followed by a dev_t.  The former is the type of
67 	 * the file (mode & S_IFMT), the latter is the st_rdev field.  Be
68 	 * sure to clear any padding that may be found in bkey.
69 	 */
70 	memset(&bkey, 0, sizeof(bkey));
71 	bkey.dev = dev;
72 	bkey.type = type;
73 	key.data = &bkey;
74 	key.size = sizeof(bkey);
75 	return ((db->get)(db, &key, &data, 0) ? "??" : (char *)data.data);
76 }
77