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hostname.c revision 1.8 
      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 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 /*static char sccsid[] = "from: @(#)hostname.c	8.1 (Berkeley) 5/31/93";*/
     42 static char *rcsid = "$Id: hostname.c,v 1.8 1994/09/26 06:53:23 mycroft Exp $";
     43 #endif /* not lint */
     44 
     45 #include <sys/param.h>
     46 
     47 #include <err.h>
     48 #include <stdio.h>
     49 #include <stdlib.h>
     50 #include <string.h>
     51 #include <unistd.h>
     52 
     53 void usage __P((void));
     54 
     55 int
     56 main(argc, argv)
     57 	int argc;
     58 	char *argv[];
     59 {
     60 	int ch, sflag;
     61 	char *p, hostname[MAXHOSTNAMELEN];
     62 
     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 		if (sflag && (p = strchr(hostname, '.')))
     86 			*p = '\0';
     87 		(void)printf("%s\n", hostname);
     88 	}
     89 	exit(0);
     90 }
     91 
     92 void
     93 usage()
     94 {
     95 
     96 	(void)fprintf(stderr, "usage: hostname [-s] [name-of-host]\n");
     97 	exit(1);
     98 }
     99