1/* vi: set sw=4 ts=4: */
2/*
3 * Mini logname implementation for busybox
4 *
5 * Copyright (C) 2000  Edward Betts <edward@debian.org>.
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8 */
9
10/* BB_AUDIT SUSv3 compliant */
11/* http://www.opengroup.org/onlinepubs/007904975/utilities/logname.html */
12
13/* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
14 *
15 * SUSv3 specifies the string used is that returned from getlogin().
16 * The previous implementation used getpwuid() for geteuid(), which
17 * is _not_ the same.  Erik apparently made this change almost 3 years
18 * ago to avoid failing when no utmp was available.  However, the
19 * correct course of action wrt SUSv3 for a failing getlogin() is
20 * a diagnostic message and an error return.
21 */
22
23#include "libbb.h"
24
25/* This is a NOFORK applet. Be very careful! */
26
27int logname_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
28int logname_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
29{
30	char buf[64];
31
32	if (argv[1]) {
33		bb_show_usage();
34	}
35
36	/* Using _r function - avoid pulling in static buffer from libc */
37	if (getlogin_r(buf, sizeof(buf)) == 0) {
38		puts(buf);
39		return fflush_all();
40	}
41
42	bb_perror_msg_and_die("getlogin");
43}
44