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"
18 //usage: "\n -s Print nothing, only return exit status"
21 //usage:#define tty_example_usage
23 //usage: "/dev/tty2\n"
27 int tty_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
28 int tty_main(int argc UNUSED_PARAM
, char **argv
)
31 IF_INCLUDE_SUSv2(int silent
;) /* Note: No longer relevant in SUSv3. */
34 xfunc_error_retval
= 2; /* SUSv3 requires > 1 for error. */
36 IF_INCLUDE_SUSv2(silent
= getopt32(argv
, "s");)
37 IF_INCLUDE_SUSv2(argv
+= optind
;)
38 IF_NOT_INCLUDE_SUSv2(argv
+= 1;)
40 /* gnu tty outputs a warning that it is ignoring all args. */
41 bb_warn_ignoring_args(argv
[0]);
43 retval
= EXIT_SUCCESS
;
45 s
= xmalloc_ttyname(STDIN_FILENO
);
47 /* According to SUSv3, ttyname can fail with EBADF or ENOTTY.
48 * We know the file descriptor is good, so failure means not a tty. */
50 retval
= EXIT_FAILURE
;
52 IF_INCLUDE_SUSv2(if (!silent
) puts(s
);)
53 IF_NOT_INCLUDE_SUSv2(puts(s
);)
55 fflush_stdout_and_exit(retval
);