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 #if 0 33 #ifndef lint 34 static char const copyright[] = 35 "@(#) Copyright (c) 1988, 1993\n\ 36 The Regents of the University of California. All rights reserved.\n"; 37 #endif /* not lint */ 38 39 #endif 40 #include <sys/cdefs.h> 41 #include <sys/param.h> 42 43 #include <err.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <unistd.h> 48 49 static void usage(void) __dead2; 50 51 int 52 main(int argc, char *argv[]) 53 { 54 int ch, sflag, dflag; 55 char hostname[MAXHOSTNAMELEN], *hostp, *p; 56 57 sflag = 0; 58 dflag = 0; 59 while ((ch = getopt(argc, argv, "fsd")) != -1) 60 switch (ch) { 61 case 'f': 62 /* 63 * On Linux, "hostname -f" prints FQDN. 64 * BSD "hostname" always prints FQDN by 65 * default, so we accept but ignore -f. 66 */ 67 break; 68 case 's': 69 sflag = 1; 70 break; 71 case 'd': 72 dflag = 1; 73 break; 74 case '?': 75 default: 76 usage(); 77 } 78 argc -= optind; 79 argv += optind; 80 81 if (argc > 1 || (sflag && dflag)) 82 usage(); 83 84 if (*argv) { 85 if (sethostname(*argv, (int)strlen(*argv))) 86 err(1, "sethostname"); 87 } else { 88 hostp = hostname; 89 if (gethostname(hostname, (int)sizeof(hostname))) 90 err(1, "gethostname"); 91 if (sflag) { 92 p = strchr(hostname, '.'); 93 if (p != NULL) 94 *p = '\0'; 95 } else if (dflag) { 96 p = strchr(hostname, '.'); 97 if (p != NULL) 98 hostp = p + 1; 99 } 100 (void)printf("%s\n", hostp); 101 } 102 exit(0); 103 } 104 105 static void 106 usage(void) 107 { 108 109 (void)fprintf(stderr, "usage: hostname [-f] [-s | -d] [name-of-host]\n"); 110 exit(1); 111 } 112