1 /* vi: set sw=4 ts=4: */
3 * tty implementation for busybox
5 * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
10 /* BB_AUDIT SUSv4 compliant */
11 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/tty.html */
13 //usage:#define tty_trivial_usage
15 //usage:#define tty_full_usage "\n\n"
16 //usage: "Print file name of stdin's terminal"
17 //usage: IF_INCLUDE_SUSv2( "\n"
19 //usage: "\n -s Print nothing, only return exit status"
22 //usage:#define tty_example_usage
24 //usage: "/dev/tty2\n"
28 int tty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
29 int tty_main(int argc UNUSED_PARAM, char **argv)
32 IF_INCLUDE_SUSv2(int silent;) /* Note: No longer relevant in SUSv3. */
35 xfunc_error_retval = 2; /* SUSv3 requires > 1 for error. */
37 IF_INCLUDE_SUSv2(silent = getopt32(argv, "s");)
38 IF_INCLUDE_SUSv2(argv += optind;)
39 IF_NOT_INCLUDE_SUSv2(argv += 1;)
41 /* gnu tty outputs a warning that it is ignoring all args. */
42 bb_warn_ignoring_args(argv[0]);
44 retval = EXIT_SUCCESS;
46 s = xmalloc_ttyname(STDIN_FILENO);
48 /* According to SUSv3, ttyname can fail with EBADF or ENOTTY.
49 * We know the file descriptor is good, so failure means not a tty. */
51 retval = EXIT_FAILURE;
53 IF_INCLUDE_SUSv2(if (!silent) puts(s);)
54 IF_NOT_INCLUDE_SUSv2(puts(s);)
56 fflush_stdout_and_exit(retval);