1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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/param.h> 33 34 #include <err.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include <string.h> 38 #include <unistd.h> 39 40 static void usage(void) __dead2; 41 42 int 43 main(int argc, char *argv[]) 44 { 45 int ch, sflag, dflag; 46 char hostname[MAXHOSTNAMELEN], *hostp, *p; 47 48 sflag = 0; 49 dflag = 0; 50 while ((ch = getopt(argc, argv, "fsd")) != -1) 51 switch (ch) { 52 case 'f': 53 /* 54 * On Linux, "hostname -f" prints FQDN. 55 * BSD "hostname" always prints FQDN by 56 * default, so we accept but ignore -f. 57 */ 58 break; 59 case 's': 60 sflag = 1; 61 break; 62 case 'd': 63 dflag = 1; 64 break; 65 case '?': 66 default: 67 usage(); 68 } 69 argc -= optind; 70 argv += optind; 71 72 if (argc > 1 || (sflag && dflag)) 73 usage(); 74 75 if (*argv) { 76 if (sethostname(*argv, (int)strlen(*argv))) 77 err(1, "sethostname"); 78 } else { 79 hostp = hostname; 80 if (gethostname(hostname, (int)sizeof(hostname))) 81 err(1, "gethostname"); 82 if (sflag) { 83 p = strchr(hostname, '.'); 84 if (p != NULL) 85 *p = '\0'; 86 } else if (dflag) { 87 p = strchr(hostname, '.'); 88 if (p != NULL) 89 hostp = p + 1; 90 } 91 (void)printf("%s\n", hostp); 92 } 93 exit(0); 94 } 95 96 static void 97 usage(void) 98 { 99 100 (void)fprintf(stderr, "usage: hostname [-f] [-s | -d] [name-of-host]\n"); 101 exit(1); 102 } 103