1 /* logname -- print user's login name
2 Copyright (C) 1990-2023 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 #include <config.h>
18 #include <stdio.h>
19 #include <sys/types.h>
20
21 #include "system.h"
22 #include "long-options.h"
23 #include "quote.h"
24
25 /* The official name of this program (e.g., no 'g' prefix). */
26 #define PROGRAM_NAME "logname"
27
28 #define AUTHORS proper_name ("FIXME: unknown")
29
30 void
usage(int status)31 usage (int status)
32 {
33 if (status != EXIT_SUCCESS)
34 emit_try_help ();
35 else
36 {
37 printf (_("Usage: %s [OPTION]\n"), program_name);
38 fputs (_("\
39 Print the user's login name.\n\
40 \n\
41 "), stdout);
42 fputs (HELP_OPTION_DESCRIPTION, stdout);
43 fputs (VERSION_OPTION_DESCRIPTION, stdout);
44 emit_ancillary_info (PROGRAM_NAME);
45 }
46 exit (status);
47 }
48
49 int
main(int argc,char ** argv)50 main (int argc, char **argv)
51 {
52 char *cp;
53
54 initialize_main (&argc, &argv);
55 set_program_name (argv[0]);
56 setlocale (LC_ALL, "");
57 bindtextdomain (PACKAGE, LOCALEDIR);
58 textdomain (PACKAGE);
59
60 atexit (close_stdout);
61
62 parse_gnu_standard_options_only (argc, argv, PROGRAM_NAME, PACKAGE_NAME,
63 Version, true, usage, AUTHORS,
64 (char const *) nullptr);
65
66 if (optind < argc)
67 {
68 error (0, 0, _("extra operand %s"), quote (argv[optind]));
69 usage (EXIT_FAILURE);
70 }
71
72 /* POSIX requires using getlogin (or equivalent code) and prohibits
73 using a fallback technique. */
74 cp = getlogin ();
75 if (! cp)
76 error (EXIT_FAILURE, 0, _("no login name"));
77
78 puts (cp);
79 return EXIT_SUCCESS;
80 }
81