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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * $FreeBSD: src/lib/libc/gen/devname.c,v 1.2.2.2 2001/07/31 20:10:19 tmm Exp $
  30  * $DragonFly: src/lib/libc/gen/devname.c,v 1.6 2005/04/26 16:59:56 joerg Exp $
  31  *
  32  * @(#)devname.c        8.2 (Berkeley) 4/29/95
  33  */
  34
  35 #include <sys/types.h>
  36 #include <sys/stat.h>
  37 #include <sys/sysctl.h>
  38
  39 #include <db.h>
  40 #include <err.h>
  41 #include <fcntl.h>
  42 #include <paths.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46
  47 #define DEVNAME_DEVFS_COMPAT 1
  48
  49 #ifdef DEVNAME_DEVFS_COMPAT
  50 static char *
  51 xdevname(dev_t dev, mode_t type)
  52 {
  53         struct {
  54                 mode_t type;
  55                 dev_t dev;
  56         } bkey;
  57         static DB *db;
  58         static int failure;
  59         DBT data, key;
  60
  61         if (!db && !failure &&
  62             !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
  63                 warn("warning: %s", _PATH_DEVDB);
  64                 failure = 1;
  65         }
  66         if (failure)
  67                 return (NULL);
  68
  69         /*
  70          * Keys are a mode_t followed by a dev_t.  The former is the type of
  71          * the file (mode & S_IFMT), the latter is the st_rdev field.  Be
  72          * sure to clear any padding that may be found in bkey.
  73          */
  74         memset(&bkey, 0, sizeof(bkey));
  75         bkey.dev = dev;
  76         bkey.type = type;
  77         key.data = &bkey;
  78         key.size = sizeof(bkey);
  79         return ((db->get)(db, &key, &data, 0) ? NULL : (char *)data.data);
  80 }
  81 #endif
  82
  83 char *
  84 devname_r(dev_t dev, mode_t type, char *buf, size_t len)
  85 {
  86         char *r;
  87         size_t n = len;
  88
  89         if (sysctlbyname("kern.devname", buf, &n, &dev, sizeof(dev)) == 0)
  90                 return buf;
  91
  92 #ifdef DEVNAME_DEVFS_COMPAT
  93         /* Fall back to old method if compat for devfs is set */
  94         /* First check the DB file. */
  95         r = xdevname(dev, type);
  96         if (r != NULL) {
  97                 strlcpy(buf, r, len);
  98                 return (buf);
  99         }
 100 #endif
 101
 102         /* Finally just format it */
 103         snprintf(buf, len, "#%c%d:0x%x",
 104             (type & S_IFMT) == S_IFCHR ? 'C' : 'B',
 105             major(dev), minor(dev));
 106
 107         return (buf);
 108 }
 109
 110 char *
 111 devname(dev_t dev, mode_t type)
 112 {
 113         static char buf[30];     /* XXX: pick up from <sys/conf.h> */
 114
 115         strlcpy(buf, devname_r(dev, type, buf, sizeof(buf)), sizeof(buf));
 116
 117         return (buf);
 118 }