/*      $OpenBSD: hostname.c,v 1.10 2016/02/01 22:27:25 gsoares Exp $   */
/*      $NetBSD: hostname.c,v 1.10 1995/09/07 06:28:40 jtc Exp $        */

/*
 * Copyright (c) 1988, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>

extern  char *__progname;

static void __dead usage(void);

int
main(int argc, char *argv[])
{
        int ch, sflag;
        char *p, hostname[HOST_NAME_MAX+1];

        sflag = 0;
        while ((ch = getopt(argc, argv, "s")) != -1)
                switch (ch) {
                case 's':
                        sflag = 1;
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc > 1)
                usage();

        if (*argv) {
                if (sethostname(*argv, strlen(*argv)))
                        err(1, "sethostname");
        } else {
                if (gethostname(hostname, sizeof(hostname)))
                        err(1, "gethostname");
                if (sflag && (p = strchr(hostname, '.')))
                        *p = '\0';
                (void)printf("%s\n", hostname);
        }
        return(0);
}

static void __dead
usage(void)
{
        (void)fprintf(stderr, "usage: %s [-s] [name-of-host]\n", __progname);
        exit(1);
}