blob: ff6f2bb3bbcaa9e653b7d4be349d23f82fe94af1 [file] [log] [blame]
/* vi: set sw=4 ts=4: */
* tty implementation for busybox
* Copyright (C) 2003 Manuel Novoa III <>
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
//config:config TTY
//config: bool "tty (3.6 kb)"
//config: default y
//config: help
//config: tty is used to print the name of the current terminal to
//config: standard output.
//kbuild:lib-$(CONFIG_TTY) += tty.o
/* BB_AUDIT SUSv4 compliant */
/* */
//usage:#define tty_trivial_usage
//usage: ""
//usage:#define tty_full_usage "\n\n"
//usage: "Print file name of stdin's terminal"
//usage: IF_INCLUDE_SUSv2( "\n"
//usage: "\n -s Print nothing, only return exit status"
//usage: )
//usage:#define tty_example_usage
//usage: "$ tty\n"
//usage: "/dev/tty2\n"
#include "libbb.h"
int tty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tty_main(int argc UNUSED_PARAM, char **argv)
const char *s;
IF_INCLUDE_SUSv2(int silent;) /* Note: No longer relevant in SUSv3. */
int retval;
xfunc_error_retval = 2; /* SUSv3 requires > 1 for error. */
IF_INCLUDE_SUSv2(silent = getopt32(argv, "s");)
IF_INCLUDE_SUSv2(argv += optind;)
IF_NOT_INCLUDE_SUSv2(argv += 1;)
/* gnu tty outputs a warning that it is ignoring all args. */
retval = EXIT_SUCCESS;
s = xmalloc_ttyname(STDIN_FILENO);
if (s == NULL) {
/* According to SUSv3, ttyname can fail with EBADF or ENOTTY.
* We know the file descriptor is good, so failure means not a tty. */
s = "not a tty";
retval = EXIT_FAILURE;
IF_INCLUDE_SUSv2(if (!silent) puts(s);)