devname.c revision 1.17
1 /* $NetBSD: devname.c,v 1.17 2008/04/28 20:22:59 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 2000 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Simon Burge. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c) 1992 Keith Muller. 34 * Copyright (c) 1989, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * This code is derived from software contributed to Berkeley by 38 * Keith Muller of the University of California, San Diego. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 3. Neither the name of the University nor the names of its contributors 49 * may be used to endorse or promote products derived from this software 50 * without specific prior written permission. 51 * 52 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 53 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 55 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 56 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 57 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 58 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 59 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 60 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 62 * SUCH DAMAGE. 63 */ 64 65 #include <sys/cdefs.h> 66 #if defined(LIBC_SCCS) && !defined(lint) 67 #if 0 68 static char sccsid[] = "@(#)devname.c 8.2 (Berkeley) 4/29/95"; 69 #else 70 __RCSID("$NetBSD: devname.c,v 1.17 2008/04/28 20:22:59 martin Exp $"); 71 #endif 72 #endif /* LIBC_SCCS and not lint */ 73 74 #include "namespace.h" 75 #include <sys/types.h> 76 #include <sys/stat.h> 77 #include <sys/param.h> 78 79 #include <db.h> 80 #include <fcntl.h> 81 #include <paths.h> 82 #include <stdio.h> 83 #include <string.h> 84 #include <stdlib.h> 85 #include <err.h> 86 87 #ifdef __weak_alias 88 __weak_alias(devname,_devname) 89 #endif 90 91 #define DEV_SZ 317 /* show be prime for best results */ 92 #define VALID 1 /* entry and devname are valid */ 93 #define INVALID 2 /* entry valid, devname NOT valid */ 94 95 typedef struct devc { 96 int valid; /* entry valid? */ 97 dev_t dev; /* cached device */ 98 mode_t type; /* cached file type */ 99 char name[NAME_MAX]; /* device name */ 100 } DEVC; 101 102 char * 103 devname(dev, type) 104 dev_t dev; 105 mode_t type; 106 { 107 struct { 108 mode_t type; 109 dev_t dev; 110 } bkey; 111 static DB *db; 112 static int failure; 113 DBT data, key; 114 DEVC *ptr, **pptr; 115 static DEVC **devtb = NULL; 116 static dev_t pts = (dev_t)~1; 117 118 if (!db && !failure && 119 !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) { 120 warn("warning: %s", _PATH_DEVDB); 121 failure = 1; 122 } 123 /* initialise dev cache */ 124 if (!failure && devtb == NULL) { 125 devtb = (DEVC **)calloc(DEV_SZ, sizeof(DEVC *)); 126 if (devtb == NULL) 127 failure= 1; 128 } 129 if (failure) 130 return (NULL); 131 132 /* see if we have this dev/type cached */ 133 pptr = devtb + ((dev + type) % DEV_SZ); 134 ptr = *pptr; 135 136 if (ptr && ptr->valid > 0 && ptr->dev == dev && ptr->type == type) { 137 if (ptr->valid == VALID) 138 return (ptr->name); 139 return (NULL); 140 } 141 142 if (ptr == NULL) 143 *pptr = ptr = (DEVC *)malloc(sizeof(DEVC)); 144 145 /* 146 * Keys are a mode_t followed by a dev_t. The former is the type of 147 * the file (mode & S_IFMT), the latter is the st_rdev field. Be 148 * sure to clear any padding that may be found in bkey. 149 */ 150 memset(&bkey, 0, sizeof(bkey)); 151 bkey.dev = dev; 152 bkey.type = type; 153 key.data = &bkey; 154 key.size = sizeof(bkey); 155 if ((db->get)(db, &key, &data, 0) == 0) { 156 if (ptr == NULL) 157 return (char *)data.data; 158 ptr->dev = dev; 159 ptr->type = type; 160 strncpy(ptr->name, (char *)data.data, NAME_MAX); 161 ptr->name[NAME_MAX - 1] = '\0'; 162 ptr->valid = VALID; 163 } else { 164 if (ptr == NULL) 165 return (NULL); 166 ptr->valid = INVALID; 167 if (type == S_IFCHR) { 168 if (pts == (dev_t)~1) 169 pts = getdevmajor("pts", S_IFCHR); 170 if (pts != (dev_t)~0 && major(dev) == pts) { 171 (void)snprintf(ptr->name, sizeof(ptr->name), 172 "%s%d", _PATH_DEV_PTS + 173 sizeof(_PATH_DEV) - 1, minor(dev)); 174 ptr->valid = VALID; 175 } 176 } 177 ptr->dev = dev; 178 ptr->type = type; 179 } 180 if (ptr->valid == VALID) 181 return (ptr->name); 182 else 183 return (NULL); 184 } 185
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