1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 */
7
8 #if defined(LIBC_SCCS) && !defined(lint)
9 static char sccsid[] = "@(#)devname.c 8.2 (Berkeley) 04/29/95";
10 #endif /* LIBC_SCCS and not lint */
11
12 #include <sys/types.h>
13
14 #include <db.h>
15 #include <err.h>
16 #include <errno.h>
17 #include <fcntl.h>
18 #include <paths.h>
19 #include <stdio.h>
20 #include <string.h>
21
22 char *
devname(dev,type)23 devname(dev, type)
24 dev_t dev;
25 mode_t type;
26 {
27 struct {
28 mode_t type;
29 dev_t dev;
30 } bkey;
31 static DB *db;
32 static int failure;
33 DBT data, key;
34
35 if (!db && !failure &&
36 !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
37 warn("warning: %s", _PATH_DEVDB);
38 failure = 1;
39 }
40 if (failure)
41 return (NULL);
42
43 /*
44 * Keys are a mode_t followed by a dev_t. The former is the type of
45 * the file (mode & S_IFMT), the latter is the st_rdev field. Be
46 * sure to clear any padding that may be found in bkey.
47 */
48 memset(&bkey, 0, sizeof(bkey));
49 bkey.dev = dev;
50 bkey.type = type;
51 key.data = &bkey;
52 key.size = sizeof(bkey);
53 return ((db->get)(db, &key, &data, 0) ? NULL : (char *)data.data);
54 }
55