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 * $FreeBSD: src/lib/libc/gen/devname.c,v 1.2.2.2 2001/07/31 20:10:19 tmm Exp $ 30 * 31 * @(#)devname.c 8.2 (Berkeley) 4/29/95 32 */ 33 34 #include "namespace.h" 35 #include <sys/types.h> 36 #include <sys/stat.h> 37 #include <sys/param.h> 38 #include <sys/sysctl.h> 39 40 #include <err.h> 41 #include <fcntl.h> 42 #include <paths.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include "un-namespace.h" 47 48 #include <db.h> 49 50 #define DEVNAME_DEVFS_COMPAT 1 51 52 #ifdef DEVNAME_DEVFS_COMPAT 53 static char * 54 xdevname(dev_t dev, mode_t type) 55 { 56 struct { 57 mode_t type; 58 dev_t dev; 59 } bkey; 60 static DB *db; 61 static int failure; 62 DBT data, key; 63 64 if (!db && !failure && 65 !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) { 66 _warn("warning: %s", _PATH_DEVDB); 67 failure = 1; 68 } 69 if (failure) 70 return (NULL); 71 72 /* 73 * Keys are a mode_t followed by a dev_t. The former is the type of 74 * the file (mode & S_IFMT), the latter is the st_rdev field. Be 75 * sure to clear any padding that may be found in bkey. 76 */ 77 memset(&bkey, 0, sizeof(bkey)); 78 bkey.dev = dev; 79 bkey.type = type; 80 key.data = &bkey; 81 key.size = sizeof(bkey); 82 return ((db->get)(db, &key, &data, 0) ? NULL : (char *)data.data); 83 } 84 #endif 85 86 char * 87 devname_r(dev_t dev, mode_t type, char *buf, size_t len) 88 { 89 char *r; 90 size_t n = len; 91 92 if (sysctlbyname("kern.devname", buf, &n, &dev, sizeof(dev)) == 0) 93 return buf; 94 95 #ifdef DEVNAME_DEVFS_COMPAT 96 /* Fall back to old method if compat for devfs is set */ 97 /* First check the DB file. */ 98 r = xdevname(dev, type); 99 if (r != NULL) { 100 strlcpy(buf, r, len); 101 return (buf); 102 } 103 #endif 104 105 /* Finally just format it */ 106 snprintf(buf, len, "#%c%d:0x%x", 107 (type & S_IFMT) == S_IFCHR ? 'C' : 'B', 108 major(dev), minor(dev)); 109 110 return (buf); 111 } 112 113 char * 114 devname(dev_t dev, mode_t type) 115 { 116 static char buf[MAXPATHLEN]; 117 118 strlcpy(buf, devname_r(dev, type, buf, sizeof(buf)), sizeof(buf)); 119 120 return (buf); 121 } 122