devname.c revision 1.9 1 /* $NetBSD: devname.c,v 1.9 2000/06/05 06:12:49 simonb 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 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39 /*-
40 * Copyright (c) 1992 Keith Muller.
41 * Copyright (c) 1989, 1993
42 * The Regents of the University of California. All rights reserved.
43 *
44 * This code is derived from software contributed to Berkeley by
45 * Keith Muller of the University of California, San Diego.
46 *
47 * Redistribution and use in source and binary forms, with or without
48 * modification, are permitted provided that the following conditions
49 * are met:
50 * 1. Redistributions of source code must retain the above copyright
51 * notice, this list of conditions and the following disclaimer.
52 * 2. Redistributions in binary form must reproduce the above copyright
53 * notice, this list of conditions and the following disclaimer in the
54 * documentation and/or other materials provided with the distribution.
55 * 3. All advertising materials mentioning features or use of this software
56 * must display the following acknowledgement:
57 * This product includes software developed by the University of
58 * California, Berkeley and its contributors.
59 * 4. Neither the name of the University nor the names of its contributors
60 * may be used to endorse or promote products derived from this software
61 * without specific prior written permission.
62 *
63 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
64 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
65 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
66 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
67 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
68 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
69 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
70 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
71 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
72 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
73 * SUCH DAMAGE.
74 */
75
76 #include <sys/cdefs.h>
77 #if defined(LIBC_SCCS) && !defined(lint)
78 #if 0
79 static char sccsid[] = "@(#)devname.c 8.2 (Berkeley) 4/29/95";
80 #else
81 __RCSID("$NetBSD: devname.c,v 1.9 2000/06/05 06:12:49 simonb Exp $");
82 #endif
83 #endif /* LIBC_SCCS and not lint */
84
85 #include "namespace.h"
86 #include <sys/types.h>
87
88 #include <db.h>
89 #include <fcntl.h>
90 #include <paths.h>
91 #include <stdio.h>
92 #include <string.h>
93 #include <stdlib.h>
94 #include <err.h>
95
96 #ifdef __weak_alias
97 __weak_alias(devname,_devname)
98 #endif
99
100 #define DEV_SZ 317 /* show be prime for best results */
101 #define VALID 1 /* entry and devname are valid */
102 #define INVALID 2 /* entry valid, devname NOT valid */
103
104 typedef struct devc {
105 int valid; /* entry valid? */
106 dev_t dev; /* cached device */
107 mode_t type; /* cached file type */
108 char name[NAME_MAX]; /* device name */
109 } DEVC;
110
111 char *
112 devname(dev, type)
113 dev_t dev;
114 mode_t type;
115 {
116 struct {
117 mode_t type;
118 dev_t dev;
119 } bkey;
120 static DB *db;
121 static int failure;
122 DBT data, key;
123 DEVC *ptr, **pptr;
124 static DEVC **devtb = NULL;
125
126 if (!db && !failure &&
127 !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
128 warn("warning: %s", _PATH_DEVDB);
129 failure = 1;
130 }
131 /* initialise dev cache */
132 if (!failure && devtb == NULL) {
133 devtb = (DEVC **)calloc(DEV_SZ, sizeof(DEVC *));
134 if (devtb == NULL)
135 failure= 1;
136 }
137 if (failure)
138 return (NULL);
139
140 /* see if we have this dev/type cached */
141 pptr = devtb + ((dev + type) % DEV_SZ);
142 ptr = *pptr;
143
144 if (ptr && ptr->valid > 0 && ptr->dev == dev && ptr->type == type) {
145 if (ptr->valid == VALID)
146 return (ptr->name);
147 return (NULL);
148 }
149
150 if (ptr == NULL)
151 *pptr = ptr = (DEVC *)malloc(sizeof(DEVC));
152
153 /*
154 * Keys are a mode_t followed by a dev_t. The former is the type of
155 * the file (mode & S_IFMT), the latter is the st_rdev field. Be
156 * sure to clear any padding that may be found in bkey.
157 */
158 memset(&bkey, 0, sizeof(bkey));
159 bkey.dev = dev;
160 bkey.type = type;
161 key.data = &bkey;
162 key.size = sizeof(bkey);
163 if ((db->get)(db, &key, &data, 0) == 0) {
164 if (ptr == NULL)
165 return (char *)data.data;
166 ptr->dev = dev;
167 ptr->type = type;
168 strncpy(ptr->name, (char *)data.data, NAME_MAX);
169 ptr->name[NAME_MAX - 1] = '\0';
170 ptr->valid = VALID;
171 return (ptr->name);
172 } else {
173 if (ptr == NULL)
174 return (NULL);
175 ptr->dev = dev;
176 ptr->type = type;
177 ptr->valid = INVALID;
178 return (NULL);
179 }
180 }
181