LXR busybox/coreutils/logname.c

   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 source tree.
   8 */
   9/* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
  10 *
  11 * SUSv3 specifies the string used is that returned from getlogin().
  12 * The previous implementation used getpwuid() for geteuid(), which
  13 * is _not_ the same.  Erik apparently made this change almost 3 years
  14 * ago to avoid failing when no utmp was available.  However, the
  15 * correct course of action wrt SUSv3 for a failing getlogin() is
  16 * a diagnostic message and an error return.
  17 */
  18//config:config LOGNAME
  19//config:       bool "logname (1.1 kb)"
  20//config:       default y
  21//config:       help
  22//config:       logname is used to print the current user's login name.
  23
  24//applet:IF_LOGNAME(APPLET_NOFORK(logname, logname, BB_DIR_USR_BIN, BB_SUID_DROP, logname))
  25
  26//kbuild:lib-$(CONFIG_LOGNAME) += logname.o
  27
  28/* BB_AUDIT SUSv3 compliant */
  29/* http://www.opengroup.org/onlinepubs/007904975/utilities/logname.html */
  30
  31//usage:#define logname_trivial_usage
  32//usage:       ""
  33//usage:#define logname_full_usage "\n\n"
  34//usage:       "Print the name of the current user"
  35//usage:
  36//usage:#define logname_example_usage
  37//usage:       "$ logname\n"
  38//usage:       "root\n"
  39
  40#include "libbb.h"
  41
  42/* This is a NOFORK applet. Be very careful! */
  43
  44int logname_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  45int logname_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
  46{
  47        char buf[64];
  48
  49        if (argv[1]) {
  50                bb_show_usage();
  51        }
  52
  53        /* Using _r function - avoid pulling in static buffer from libc */
  54        if (getlogin_r(buf, sizeof(buf)) == 0) {
  55                puts(buf);
  56                return fflush_all();
  57        }
  58
  59        bb_perror_msg_and_die("getlogin");
  60}
  61