1 /* hostname - set or print the name of current host system
2 Copyright (C) 1994-2023 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17 /* Written by Jim Meyering. */
18
19 #include <config.h>
20 #include <stdio.h>
21 #include <sys/types.h>
22
23 #include "system.h"
24 #include "long-options.h"
25 #include "quote.h"
26 #include "xgethostname.h"
27
28 /* The official name of this program (e.g., no 'g' prefix). */
29 #define PROGRAM_NAME "hostname"
30
31 #define AUTHORS proper_name ("Jim Meyering")
32
33 #ifndef HAVE_SETHOSTNAME
34 # if defined HAVE_SYSINFO && defined HAVE_SYS_SYSTEMINFO_H
35 # include <sys/systeminfo.h>
36 # endif
37
38 static int
sethostname(char const * name,size_t namelen)39 sethostname (char const *name, size_t namelen)
40 {
41 # if defined HAVE_SYSINFO && defined HAVE_SYS_SYSTEMINFO_H
42 /* Using sysinfo() is the SVR4 mechanism to set a hostname. */
43 return (sysinfo (SI_SET_HOSTNAME, name, namelen) < 0 ? -1 : 0);
44 # else
45 errno = ENOTSUP;
46 return -1;
47 # endif
48 }
49 #endif
50
51 void
usage(int status)52 usage (int status)
53 {
54 if (status != EXIT_SUCCESS)
55 emit_try_help ();
56 else
57 {
58 printf (_("\
59 Usage: %s [NAME]\n\
60 or: %s OPTION\n\
61 Print or set the hostname of the current system.\n\
62 \n\
63 "),
64 program_name, program_name);
65 fputs (HELP_OPTION_DESCRIPTION, stdout);
66 fputs (VERSION_OPTION_DESCRIPTION, stdout);
67 emit_ancillary_info (PROGRAM_NAME);
68 }
69 exit (status);
70 }
71
72 int
main(int argc,char ** argv)73 main (int argc, char **argv)
74 {
75 char *hostname;
76
77 initialize_main (&argc, &argv);
78 set_program_name (argv[0]);
79 setlocale (LC_ALL, "");
80 bindtextdomain (PACKAGE, LOCALEDIR);
81 textdomain (PACKAGE);
82
83 atexit (close_stdout);
84
85 parse_gnu_standard_options_only (argc, argv, PROGRAM_NAME, PACKAGE_NAME,
86 Version, true, usage, AUTHORS,
87 (char const *) nullptr);
88
89 if (optind + 1 < argc)
90 {
91 error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
92 usage (EXIT_FAILURE);
93 }
94
95 if (optind + 1 == argc)
96 {
97 /* Set hostname to operand. */
98 char const *name = argv[optind];
99 if (sethostname (name, strlen (name)) != 0)
100 error (EXIT_FAILURE, errno, _("cannot set name to %s"),
101 quote (name));
102 }
103 else
104 {
105 hostname = xgethostname ();
106 if (hostname == nullptr)
107 error (EXIT_FAILURE, errno, _("cannot determine hostname"));
108 puts (hostname);
109 }
110
111 main_exit (EXIT_SUCCESS);
112 }
113