gen.subproj/devname.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1989, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  * 3. All advertising materials mentioning features or use of this software
  35  *    must display the following acknowledgement:
  36  *      This product includes software developed by the University of
  37  *      California, Berkeley and its contributors.
  38  * 4. Neither the name of the University nor the names of its contributors
  39  *    may be used to endorse or promote products derived from this software
  40  *    without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  */
  54
  55
  56 #include <sys/types.h>
  57 #include <sys/stat.h>
  58
  59 #include <db.h>
  60 #include <dirent.h>
  61 #include <err.h>
  62 #include <errno.h>
  63 #include <fcntl.h>
  64 #include <paths.h>
  65 #include <stdio.h>
  66 #include <string.h>
  67
  68 static char buf[sizeof(_PATH_DEV) + MAXNAMLEN] = _PATH_DEV;
  69 static char *olddevname __P((dev_t, mode_t));
  70
  71 char *
  72 devname(dev, type)
  73         dev_t dev;
  74         mode_t type;
  75 {
  76         struct {
  77                 mode_t type;
  78                 dev_t dev;
  79         } bkey;
  80         static DB *db;
  81         static int failure;
  82         DBT data, key;
  83
  84         if (!db && !failure &&
  85             !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
  86                 failure = 1;
  87         }
  88         if (failure)
  89                 return (olddevname(dev, type));
  90
  91         /*
  92          * Keys are a mode_t followed by a dev_t.  The former is the type of
  93          * the file (mode & S_IFMT), the latter is the st_rdev field.  Be
  94          * sure to clear any padding that may be found in bkey.
  95          */
  96         memset(&bkey, 0, sizeof(bkey));
  97         bkey.dev = dev;
  98         bkey.type = type;
  99         key.data = &bkey;
 100         key.size = sizeof(bkey);
 101         return ((db->get)(db, &key, &data, 0) ? NULL : (char *)data.data);
 102 }
 103
 104 static char *
 105 olddevname(dev, type)
 106         dev_t dev;
 107         mode_t type;
 108 {
 109         register DIR *dp;
 110         register struct dirent *dirp;
 111         struct stat sb;
 112
 113         if ((dp = opendir(_PATH_DEV)) == NULL)
 114                 return (NULL);
 115
 116         while ( (dirp = readdir(dp)) ) {
 117                 bcopy(dirp->d_name, buf + sizeof(_PATH_DEV) - 1,
 118                     dirp->d_namlen + 1);
 119                 if (stat(buf, &sb))
 120                         continue;
 121                 if (dev != sb.st_rdev)
 122                         continue;
 123                 if (type != (sb.st_mode & S_IFMT))
 124                         continue;
 125                 (void)closedir(dp);
 126                 return (buf + sizeof(_PATH_DEV) - 1);
 127         }
 128         (void)closedir(dp);
 129         return (NULL);
 130 }