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hostname.c revision 1.5 
      1 /*
      2  * Copyright (c) 1983, 1988 Regents of the University of California.
      3  * 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 char copyright[] =
     36 "@(#) Copyright (c) 1983, 1988 Regents of the University of California.\n\
     37  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 /*static char sccsid[] = "from: @(#)hostname.c	5.4 (Berkeley) 5/31/90";*/
     42 static char rcsid[] = "$Id: hostname.c,v 1.5 1993/09/10 01:24:53 jtc Exp $";
     43 #endif /* not lint */
     44 
     45 #include <stdio.h>
     46 #include <stdlib.h>
     47 #include <string.h>
     48 #include <unistd.h>
     49 #include <sys/param.h>
     50 
     51 static void usage __P((void));
     52 
     53 main(argc,argv)
     54 	int argc;
     55 	char **argv;
     56 {
     57 	int ch, sflag;
     58 	char hostname[MAXHOSTNAMELEN], *p;
     59 
     60 	sflag = 0;
     61 	while ((ch = getopt(argc, argv, "s")) != -1)
     62 		switch((char)ch) {
     63 		case 's':
     64 			sflag = 1;
     65 			break;
     66 		case '?':
     67 		default:
     68 			usage();
     69 			/* NOTREACHED */
     70 		}
     71 	argv += optind;
     72 
     73 	if (*argv) {
     74 		if (sethostname(*argv, strlen(*argv))) {
     75 			perror("sethostname");
     76 			exit(1);
     77 		}
     78 	} else {
     79 		if (gethostname(hostname, sizeof(hostname))) {
     80 			perror("gethostname");
     81 			exit(1);
     82 		}
     83 		if (sflag && (p = index(hostname, '.')))
     84 			*p = '\0';
     85 		puts(hostname);
     86 	}
     87 	exit(0);
     88 }
     89 
     90 static void
     91 usage ()
     92 {
     93 	(void)fprintf(stderr, "usage: hostname [-s] [hostname]\n");
     94 	exit(1);
     95 }
     96