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  * 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 0
  31 #ifndef lint
  32 static char const copyright[] =
  33 "@(#) Copyright (c) 1988, 1993\n\
  34         The Regents of the University of California.  All rights reserved.\n";
  35 #endif /* not lint */
  36
  37 #ifndef lint
  38 static char sccsid[] = "@(#)hostname.c  8.1 (Berkeley) 5/31/93";
  39 #endif /* not lint */
  40 #endif
  41 #include <sys/cdefs.h>
  42 __FBSDID("$FreeBSD: src/bin/hostname/hostname.c,v 1.19 2006/12/08 07:47:08 kientzle Exp $");
  43
  44 #include <sys/param.h>
  45
  46 #include <err.h>
  47 #include <stdio.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include <unistd.h>
  51
  52 void usage(void);
  53
  54 int
  55 main(int argc, char *argv[])
  56 {
  57         int ch, sflag;
  58         char *p, hostname[MAXHOSTNAMELEN];
  59
  60         sflag = 0;
  61         while ((ch = getopt(argc, argv, "fs")) != -1)
  62                 switch (ch) {
  63                 case 'f':
  64                         /*
  65                          * On Linux, "hostname -f" prints FQDN.
  66                          * BSD "hostname" always prints FQDN by
  67                          * default, so we accept but ignore -f.
  68                          */
  69                         break;
  70                 case 's':
  71                         sflag = 1;
  72                         break;
  73                 case '?':
  74                 default:
  75                         usage();
  76                 }
  77         argc -= optind;
  78         argv += optind;
  79
  80         if (argc > 1)
  81                 usage();
  82
  83         if (*argv) {
  84                 if (sethostname(*argv, (int)strlen(*argv)))
  85                         err(1, "sethostname");
  86         } else {
  87                 if (gethostname(hostname, (int)sizeof(hostname)))
  88                         err(1, "gethostname");
  89                 if (sflag) {
  90                         p = strchr(hostname, '.');
  91                         if (p != NULL)
  92                                 *p = '\0';
  93                 }
  94                 (void)printf("%s\n", hostname);
  95         }
  96         exit(0);
  97 }
  98
  99 void
 100 usage(void)
 101 {
 102
 103         (void)fprintf(stderr, "usage: hostname [-fs] [name-of-host]\n");
 104         exit(1);
 105 }