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 * 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