busybox/coreutils/logname.c

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/* vi: set sw=4 ts=4: */
/*
* Mini logname implementation for busybox
*
* Copyright (C) 2000 Edward Betts <edward@debian.org>.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
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/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
*
* SUSv3 specifies the string used is that returned from getlogin().
* The previous implementation used getpwuid() for geteuid(), which
* is _not_ the same. Erik apparently made this change almost 3 years
* ago to avoid failing when no utmp was available. However, the
* correct course of action wrt SUSv3 for a failing getlogin() is
* a diagnostic message and an error return.
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*/
//config:config LOGNAME
//config: bool "logname"
//config: default y
//config: help
//config: logname is used to print the current user's login name.
//applet:IF_LOGNAME(APPLET_NOFORK(logname, logname, BB_DIR_USR_BIN, BB_SUID_DROP, logname))
//kbuild:lib-$(CONFIG_LOGNAME) += logname.o
/* BB_AUDIT SUSv3 compliant */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/logname.html */
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//usage:#define logname_trivial_usage
//usage: ""
//usage:#define logname_full_usage "\n\n"
//usage: "Print the name of the current user"
//usage:
//usage:#define logname_example_usage
//usage: "$ logname\n"
//usage: "root\n"
#include "libbb.h"
/* This is a NOFORK applet. Be very careful! */
int logname_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int logname_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
{
char buf[64];
if (argv[1]) {
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bb_show_usage();
}
/* Using _r function - avoid pulling in static buffer from libc */
if (getlogin_r(buf, sizeof(buf)) == 0) {
puts(buf);
return fflush_all();
}
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bb_perror_msg_and_die("getlogin");
}