1/* vi: set sw=4 ts=4: */ 2/* 3 * tty implementation for busybox 4 * 5 * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.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/tty.html */ 12 13#include "libbb.h" 14 15int tty_main(int argc, char **argv); 16int tty_main(int argc, char **argv) 17{ 18 const char *s; 19 USE_INCLUDE_SUSv2(int silent;) /* Note: No longer relevant in SUSv3. */ 20 int retval; 21 22 xfunc_error_retval = 2; /* SUSv3 requires > 1 for error. */ 23 24 USE_INCLUDE_SUSv2(silent = getopt32(argv, "s");) 25 26 /* gnu tty outputs a warning that it is ignoring all args. */ 27 bb_warn_ignoring_args(argc - optind); 28 29 retval = 0; 30 31 s = ttyname(0); 32 if (s == NULL) { 33 /* According to SUSv3, ttyname can on fail with EBADF or ENOTTY. 34 * We know the file descriptor is good, so failure means not a tty. */ 35 s = "not a tty"; 36 retval = 1; 37 } 38 USE_INCLUDE_SUSv2(if (!silent) puts(s);) 39 SKIP_INCLUDE_SUSv2(puts(s);) 40 41 fflush_stdout_and_exit(retval); 42} 43