bin/hostname/hostname.c

   1 /* $NetBSD: hostname.c,v 1.21 2014/02/13 12:00:29 elric Exp $ */
   2
   3 /*
   4  * Copyright (c) 1988, 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 #ifndef lint
  34 __COPYRIGHT("@(#) Copyright (c) 1988, 1993\
  35  The Regents of the University of California.  All rights reserved.");
  36 #endif /* not lint */
  37
  38 #ifndef lint
  39 #if 0
  40 static char sccsid[] = "@(#)hostname.c  8.2 (Berkeley) 4/28/95";
  41 #else
  42 __RCSID("$NetBSD: hostname.c,v 1.21 2014/02/13 12:00:29 elric Exp $");
  43 #endif
  44 #endif /* not lint */
  45
  46 #include <sys/param.h>
  47
  48 #include <err.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52 #include <unistd.h>
  53
  54 __dead static void usage(void);
  55
  56 int
  57 main(int argc, char *argv[])
  58 {
  59         int ch, sflag;
  60         char *p, hostname[MAXHOSTNAMELEN + 1];
  61
  62         setprogname(argv[0]);
  63         sflag = 0;
  64         while ((ch = getopt(argc, argv, "s")) != -1)
  65                 switch (ch) {
  66                 case 's':
  67                         sflag = 1;
  68                         break;
  69                 case '?':
  70                 default:
  71                         usage();
  72                 }
  73         argc -= optind;
  74         argv += optind;
  75
  76         if (argc > 1)
  77                 usage();
  78
  79         if (*argv) {
  80                 if (sethostname(*argv, strlen(*argv)))
  81                         err(1, "sethostname");
  82         } else {
  83                 if (gethostname(hostname, sizeof(hostname)))
  84                         err(1, "gethostname");
  85                 hostname[sizeof(hostname) - 1] = '\0';
  86                 if (sflag && (p = strchr(hostname, '.')))
  87                         *p = '\0';
  88                 (void)printf("%s\n", hostname);
  89         }
  90         exit(0);
  91         /* NOTREACHED */
  92 }
  93
  94 static void
  95 usage(void)
  96 {
  97         (void)fprintf(stderr, "usage: %s [-s] [name-of-host]\n",
  98             getprogname());
  99         exit(1);
 100         /* NOTREACHED */
 101 }