gen/FreeBSD/gethostname.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  * 4. 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
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)gethostname.c       8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/gen/gethostname.c,v 1.8 2007/01/09 00:27:54 imp Exp $");
  35
  36 #include <string.h>
  37 #include <sys/param.h>
  38 #include <sys/sysctl.h>
  39 #include <limits.h>
  40
  41 #include <errno.h>
  42 #include <unistd.h>
  43
  44 int
  45 gethostname(name, namelen)
  46         char *name;
  47         size_t namelen;
  48 {
  49         int mib[2];
  50
  51         mib[0] = CTL_KERN;
  52         mib[1] = KERN_HOSTNAME;
  53         if (namelen < MAXHOSTNAMELEN + 1) {
  54                 char local_buf[MAXHOSTNAMELEN + 1];
  55                 size_t local_len = sizeof(local_buf);
  56                 if (sysctl(mib, 2, local_buf, &local_len, NULL, 0) == -1) {
  57                         if (errno == ENOMEM)
  58                                 errno = ENAMETOOLONG;
  59                         return (-1);
  60                 }
  61                 strncpy(name, local_buf, namelen);
  62                 name[namelen - 1] = 0;
  63         } else {
  64         if (sysctl(mib, 2, name, &namelen, NULL, 0) == -1) {
  65                 if (errno == ENOMEM)
  66                         errno = ENAMETOOLONG;
  67                 return (-1);
  68                 }
  69         }
  70         return (0);
  71 }