lib/libc/gen/confstr.c

   1 /*      $NetBSD: confstr.c,v 1.11 2003/08/07 16:42:46 agc Exp $ */
   2
   3 /*-
   4  * Copyright (c) 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)confstr.c   8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: confstr.c,v 1.11 2003/08/07 16:42:46 agc Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include <sys/param.h>
  43 #include <sys/sysctl.h>
  44
  45 #include <errno.h>
  46 #include <paths.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include <unistd.h>
  50
  51 #ifdef __weak_alias
  52 __weak_alias(confstr,_confstr)
  53 #endif
  54
  55 size_t
  56 confstr(name, buf, len)
  57         int name;
  58         char *buf;
  59         size_t len;
  60 {
  61         size_t tlen;
  62         int mib[2], sverrno;
  63         char *p;
  64
  65         /*
  66          * POSIX 1003.2 requires errors to return 0 --
  67          * that is *really* useful.
  68          */
  69         switch (name) {
  70         case _CS_PATH:
  71                 mib[0] = CTL_USER;
  72                 mib[1] = USER_CS_PATH;
  73                 if (sysctl(mib, 2, NULL, &tlen, NULL, 0) == -1)
  74                         return 0;
  75                 if (len != 0 && buf != NULL) {
  76                         if ((p = malloc(tlen)) == NULL)
  77                                 return 0;
  78                         if (sysctl(mib, 2, p, &tlen, NULL, 0) == -1) {
  79                                 sverrno = errno;
  80                                 free(p);
  81                                 errno = sverrno;
  82                                 return 0;
  83                         }
  84                         /*
  85                          * POSIX 1003.2 requires partial return of
  86                          * the string -- that is even more useful.
  87                          */
  88                         (void)strncpy(buf, p, len - 1);
  89                         buf[len - 1] = '\0';
  90                         free(p);
  91                 }
  92                 return tlen + 1;
  93         default:
  94                 errno = EINVAL;
  95                 return 0;
  96         }
  97         /* NOTREACHED */
  98 }