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
main(int argc,char * argv[])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
usage(void)97 usage(void)
98 {
99
100 (void)fprintf(stderr, "usage: hostname [-f] [-s | -d] [name-of-host]\n");
101 exit(1);
102 }
103