devname.c revision 80552
1145519Sdarrenr/* 2145510Sdarrenr * Copyright (c) 1989, 1993 3145510Sdarrenr * The Regents of the University of California. All rights reserved. 4255332Scy * 5145510Sdarrenr * Redistribution and use in source and binary forms, with or without 6145510Sdarrenr * modification, are permitted provided that the following conditions 7145510Sdarrenr * are met: 8255332Scy * 1. Redistributions of source code must retain the above copyright 9145510Sdarrenr * notice, this list of conditions and the following disclaimer. 10145510Sdarrenr * 2. Redistributions in binary form must reproduce the above copyright 11145510Sdarrenr * notice, this list of conditions and the following disclaimer in the 12145510Sdarrenr * documentation and/or other materials provided with the distribution. 13145510Sdarrenr * 3. All advertising materials mentioning features or use of this software 14145510Sdarrenr * must display the following acknowledgement: 15145510Sdarrenr * This product includes software developed by the University of 16145510Sdarrenr * California, Berkeley and its contributors. 17145510Sdarrenr * 4. Neither the name of the University nor the names of its contributors 18145510Sdarrenr * may be used to endorse or promote products derived from this software 19145510Sdarrenr * without specific prior written permission. 20145510Sdarrenr * 21145510Sdarrenr * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22145510Sdarrenr * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23145510Sdarrenr * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24145510Sdarrenr * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25145510Sdarrenr * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26145510Sdarrenr * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27145510Sdarrenr * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28255332Scy * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29145510Sdarrenr * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30145510Sdarrenr * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31145510Sdarrenr * SUCH DAMAGE. 32255332Scy * 33255332Scy * $FreeBSD: head/lib/libc/gen/devname.c 80552 2001-07-29 22:01:55Z tmm $ 34255332Scy */ 35145510Sdarrenr 36145510Sdarrenr#if defined(LIBC_SCCS) && !defined(lint) 37145510Sdarrenrstatic char sccsid[] = "@(#)devname.c 8.2 (Berkeley) 4/29/95"; 38145510Sdarrenr#endif /* LIBC_SCCS and not lint */ 39145510Sdarrenr 40255332Scy#include <sys/types.h> 41145510Sdarrenr#include <sys/sysctl.h> 42145510Sdarrenr 43145510Sdarrenr#include <db.h> 44145510Sdarrenr#include <err.h> 45145510Sdarrenr#include <fcntl.h> 46145510Sdarrenr#include <paths.h> 47145510Sdarrenr#include <stdio.h> 48255332Scy#include <string.h> 49145510Sdarrenr#include <sys/param.h> 50145510Sdarrenr#include <sys/stat.h> 51145510Sdarrenr 52145510Sdarrenrstatic char * 53145510Sdarrenrxdevname(dev, type) 54145510Sdarrenr dev_t dev; 55145510Sdarrenr mode_t type; 56145510Sdarrenr{ 57255332Scy struct { 58145510Sdarrenr mode_t type; 59145510Sdarrenr dev_t dev; 60145510Sdarrenr } bkey; 61145510Sdarrenr 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 84char * 85devname(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