hostname/hostname.c

   1 /*
   2  * Copyright (c) 1988, 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 #ifndef lint
  35 static char const copyright[] =
  36 "@(#) Copyright (c) 1988, 1993\n\
  37         The Regents of the University of California.  All rights reserved.\n";
  38 #endif /* not lint */
  39
  40 #ifndef lint
  41 #if 0
  42 static char sccsid[] = "@(#)hostname.c  8.1 (Berkeley) 5/31/93";
  43 #endif
  44 #endif /* not lint */
  45 #include <sys/cdefs.h>
  46 __RCSID("$FreeBSD: src/bin/hostname/hostname.c,v 1.14 2002/06/30 05:13:53 obrien Exp $");
  47
  48 #include <sys/param.h>
  49
  50 #include <err.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53 #include <string.h>
  54 #include <unistd.h>
  55
  56 void usage(void);
  57
  58 int
  59 main(int argc, char *argv[])
  60 {
  61         int ch, sflag;
  62         char *p, hostname[MAXHOSTNAMELEN];
  63
  64         sflag = 0;
  65         while ((ch = getopt(argc, argv, "s")) != -1)
  66                 switch (ch) {
  67                 case 's':
  68                         sflag = 1;
  69                         break;
  70                 case '?':
  71                 default:
  72                         usage();
  73                 }
  74         argc -= optind;
  75         argv += optind;
  76
  77         if (argc > 1)
  78                 usage();
  79
  80         if (*argv) {
  81                 if (sethostname(*argv, (int)strlen(*argv)))
  82                         err(1, "sethostname");
  83         } else {
  84                 if (gethostname(hostname, (int)sizeof(hostname)))
  85                         err(1, "gethostname");
  86                 if (sflag) {
  87                         p = strchr(hostname, '.');
  88                         if (p != NULL)
  89                                 *p = '\0';
  90                 }
  91                 (void)printf("%s\n", hostname);
  92         }
  93         exit(0);
  94 }
  95
  96 void
  97 usage(void)
  98 {
  99
 100         (void)fprintf(stderr, "usage: hostname [-s] [name-of-host]\n");
 101         exit(1);
 102 }