lib/libc/gen/devname.c

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/lib/libc/gen/devname.c,v 1.2.2.2 2001/07/31 20:10:19 tmm Exp $
  34  * $DragonFly: src/lib/libc/gen/devname.c,v 1.6 2005/04/26 16:59:56 joerg Exp $
  35  *
  36  * @(#)devname.c        8.2 (Berkeley) 4/29/95
  37  */
  38
  39 #include <sys/types.h>
  40 #include <sys/stat.h>
  41 #include <sys/sysctl.h>
  42
  43 #include <db.h>
  44 #include <err.h>
  45 #include <fcntl.h>
  46 #include <paths.h>
  47 #include <stdio.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50
  51 #define DEVNAME_DEVFS_COMPAT 1
  52
  53 #ifdef DEVNAME_DEVFS_COMPAT
  54 static char *
  55 xdevname(dev_t dev, mode_t type)
  56 {
  57         struct {
  58                 mode_t type;
  59                 dev_t dev;
  60         } bkey;
  61         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                 warn("warning: %s", _PATH_DEVDB);
  68                 failure = 1;
  69         }
  70         if (failure)
  71                 return (NULL);
  72
  73         /*
  74          * Keys are a mode_t followed by a dev_t.  The former is the type of
  75          * the file (mode & S_IFMT), the latter is the st_rdev field.  Be
  76          * sure to clear any padding that may be found in bkey.
  77          */
  78         memset(&bkey, 0, sizeof(bkey));
  79         bkey.dev = dev;
  80         bkey.type = type;
  81         key.data = &bkey;
  82         key.size = sizeof(bkey);
  83         return ((db->get)(db, &key, &data, 0) ? NULL : (char *)data.data);
  84 }
  85 #endif
  86
  87 char *
  88 devname_r(dev_t dev, mode_t type, char *buf, size_t len)
  89 {
  90         char *r;
  91         size_t n = len;
  92
  93         if (sysctlbyname("kern.devname", buf, &n, &dev, sizeof(dev)) == 0)
  94                 return buf;
  95
  96 #ifdef DEVNAME_DEVFS_COMPAT
  97         /* Fall back to old method if compat for devfs is set */
  98         /* First check the DB file. */
  99         r = xdevname(dev, type);
 100         if (r != NULL) {
 101                 strlcpy(buf, r, len);
 102                 return (buf);
 103         }
 104 #endif
 105
 106         /* Finally just format it */
 107         snprintf(buf, len, "#%c%d:0x%x",
 108             (type & S_IFMT) == S_IFCHR ? 'C' : 'B',
 109             major(dev), minor(dev));
 110
 111         return (buf);
 112 }
 113
 114 char *
 115 devname(dev_t dev, mode_t type)
 116 {
 117         static char buf[30];     /* XXX: pick up from <sys/conf.h> */
 118
 119         strlcpy(buf, devname_r(dev, type, buf, sizeof(buf)), sizeof(buf));
 120
 121         return (buf);
 122 }