gen/gethostname-fbsd.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
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)gethostname.c       8.1 (Berkeley) 6/4/93";
  36 #endif /* LIBC_SCCS and not lint */
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD: src/lib/libc/gen/gethostname.c,v 1.5 2003/08/19 23:01:46 wollman Exp $");
  39
  40 #include <string.h>
  41 #include <sys/param.h>
  42 #include <sys/sysctl.h>
  43 #include <limits.h>
  44
  45 #include <errno.h>
  46
  47 int
  48 gethostname(name, namelen)
  49         char *name;
  50         size_t namelen;
  51 {
  52         int mib[2];
  53
  54         /* Kluge to avoid ABI breakage. */
  55         namelen = (int)namelen;
  56
  57         mib[0] = CTL_KERN;
  58         mib[1] = KERN_HOSTNAME;
  59         if (namelen < MAXHOSTNAMELEN + 1) {
  60                 char local_buf[MAXHOSTNAMELEN + 1];
  61                 size_t local_len = sizeof(local_buf);
  62                 if (sysctl(mib, 2, local_buf, &local_len, NULL, 0) == -1) {
  63                         if (errno == ENOMEM)
  64                                 errno = ENAMETOOLONG;
  65                         return (-1);
  66                 }
  67                 strncpy(name, local_buf, namelen);
  68                 name[namelen - 1] = 0;
  69         } else {
  70         if (sysctl(mib, 2, name, &namelen, NULL, 0) == -1) {
  71                 if (errno == ENOMEM)
  72                         errno = ENAMETOOLONG;
  73                 return (-1);
  74                 }
  75         }
  76         return (0);
  77 }