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. 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[] = "@(#)devname.c 8.2 (Berkeley) 4/29/95"; 36 #endif /* LIBC_SCCS and not lint */ 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include <sys/types.h> 41 #include <sys/sysctl.h> 42 43 #include <db.h> 44 #include <err.h> 45 #include <fcntl.h> 46 #include <paths.h> 47 #include <stdio.h> 48 #include <string.h> 49 #include <sys/param.h> 50 #include <sys/stat.h> 51 52 static char * 53 xdevname(dev, type) 54 dev_t dev; 55 mode_t type; 56 { 57 struct { 58 mode_t type; 59 dev_t dev; 60 } bkey; 61 static DB *db; 62 static int failure; 63 DBT data, key; 64 65 if (!db && !failure && 66 !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) 67 failure = 1; 68 if (failure) 69 return (NULL); 70 71 /* 72 * Keys are a mode_t followed by a dev_t. The former is the type of 73 * the file (mode & S_IFMT), the latter is the st_rdev field. Be 74 * sure to clear any padding that may be found in bkey. 75 */ 76 memset(&bkey, 0, sizeof(bkey)); 77 bkey.dev = dev; 78 bkey.type = type; 79 key.data = &bkey; 80 key.size = sizeof(bkey); 81 return ((db->get)(db, &key, &data, 0) ? NULL : (char *)data.data); 82 } 83 84 char * 85 devname(dev, type) 86 dev_t dev; 87 mode_t type; 88 { 89 static char buf[SPECNAMELEN + 1]; 90 int i; 91 size_t j; 92 char *r; 93 94 /* First check the DB file. */ 95 r = xdevname(dev, type); 96 if (r != NULL) 97 return (r); 98 99 /* Then ask the kernel. */ 100 if ((type & S_IFMT) == S_IFCHR) { 101 j = sizeof(buf); 102 i = sysctlbyname("kern.devname", buf, &j, &dev, sizeof (dev)); 103 if (i == 0) 104 return (buf); 105 } 106 107 /* Finally just format it */ 108 if (minor(dev) > 255) 109 r = "#%c:%d:0x%x"; 110 else 111 r = "#%c:%d:0x%d"; 112 snprintf(buf, SPECNAMELEN + 1, r, 113 (type & S_IFMT) == S_IFCHR ? 'C' : 'B', major(dev), minor(dev)); 114 return (buf); 115 } 116