lib/libc/gen/devname.c

   1 /*      $NetBSD: devname.c,v 1.21 2010/03/23 20:28:59 drochner 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 1.21 2010/03/23 20:28:59 drochner 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 #define DEV_SZ          317     /* show be prime for best results */
  88 #define VALID           1       /* entry and devname are valid */
  89 #define INVALID         2       /* entry valid, devname NOT valid */
  90
  91 typedef struct devc {
  92         int valid;              /* entry valid? */
  93         dev_t dev;              /* cached device */
  94         mode_t type;            /* cached file type */
  95         char name[NAME_MAX];    /* device name */
  96 } DEVC;
  97
  98 char *
  99 devname(dev, type)
 100         dev_t dev;
 101         mode_t type;
 102 {
 103         struct {
 104                 mode_t type;
 105                 dev_t dev;
 106         } bkey;
 107         struct {
 108                 mode_t type;
 109                 int32_t dev;
 110         } obkey;
 111         static DB *db;
 112         static int failure;
 113         DBT data, key;
 114         DEVC *ptr, **pptr;
 115         static DEVC **devtb = NULL;
 116         static devmajor_t pts;
 117         static int pts_valid = 0;
 118
 119         if (!db && !failure &&
 120             !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
 121                 warn("warning: %s", _PATH_DEVDB);
 122                 failure = 1;
 123         }
 124         /* initialise dev cache */
 125         if (!failure && devtb == NULL) {
 126                 devtb = calloc(DEV_SZ, sizeof(DEVC *));
 127                 if (devtb == NULL)
 128                         failure= 1;
 129         }
 130         if (failure)
 131                 return (NULL);
 132
 133         /* see if we have this dev/type cached */
 134         pptr = devtb + (size_t)((dev + type) % DEV_SZ);
 135         ptr = *pptr;
 136
 137         if (ptr && ptr->valid > 0 && ptr->dev == dev && ptr->type == type) {
 138                 if (ptr->valid == VALID)
 139                         return (ptr->name);
 140                 return (NULL);
 141         }
 142
 143         if (ptr == NULL)
 144                 *pptr = ptr = malloc(sizeof(DEVC));
 145
 146         /*
 147          * Keys are a mode_t followed by a dev_t.  The former is the type of
 148          * the file (mode & S_IFMT), the latter is the st_rdev field.  Be
 149          * sure to clear any padding that may be found in bkey.
 150          */
 151         (void)memset(&bkey, 0, sizeof(bkey));
 152         bkey.dev = dev;
 153         bkey.type = type;
 154         key.data = &bkey;
 155         key.size = sizeof(bkey);
 156         if ((db->get)(db, &key, &data, 0) == 0) {
 157 found_it:
 158                 if (ptr == NULL)
 159                         return (char *)data.data;
 160                 ptr->dev = dev;
 161                 ptr->type = type;
 162                 strncpy(ptr->name, (char *)data.data, NAME_MAX);
 163                 ptr->name[NAME_MAX - 1] = '\0';
 164                 ptr->valid = VALID;
 165         } else {
 166                 /* Look for a 32 bit dev_t. */
 167                 (void)memset(&obkey, 0, sizeof(obkey));
 168                 obkey.dev = (int32_t)(uint32_t)dev;
 169                 obkey.type = type;
 170                 key.data = &obkey;
 171                 key.size = sizeof(obkey);
 172                 if ((db->get)(db, &key, &data, 0) == 0)
 173                         goto found_it;
 174
 175                 if (ptr == NULL)
 176                         return (NULL);
 177                 ptr->valid = INVALID;
 178                 if (type == S_IFCHR) {
 179                         if (!pts_valid) {
 180                                 pts = getdevmajor("pts", S_IFCHR);
 181                                 pts_valid = 1;
 182                         }
 183                         if (pts != NODEVMAJOR && major(dev) == pts) {
 184                                 (void)snprintf(ptr->name, sizeof(ptr->name),
 185                                     "%s%d", _PATH_DEV_PTS +
 186                                     sizeof(_PATH_DEV) - 1,
 187                                     minor(dev));
 188                                 ptr->valid = VALID;
 189                         }
 190                 }
 191                 ptr->dev = dev;
 192                 ptr->type = type;
 193         }
 194         if (ptr->valid == VALID)
 195                 return (ptr->name);
 196         else
 197                 return (NULL);
 198 }