blob: 45175054e2a13509e34c2c98ac9f6ade56534f20
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 source tree. |
8 | */ |
9 | |
10 | /* BB_AUDIT SUSv4 compliant */ |
11 | /* http://www.opengroup.org/onlinepubs/9699919799/utilities/tty.html */ |
12 | |
13 | //usage:#define tty_trivial_usage |
14 | //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" |
19 | //usage: ) |
20 | //usage: |
21 | //usage:#define tty_example_usage |
22 | //usage: "$ tty\n" |
23 | //usage: "/dev/tty2\n" |
24 | |
25 | #include "libbb.h" |
26 | |
27 | int tty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
28 | int tty_main(int argc UNUSED_PARAM, char **argv) |
29 | { |
30 | const char *s; |
31 | IF_INCLUDE_SUSv2(int silent;) /* Note: No longer relevant in SUSv3. */ |
32 | int retval; |
33 | |
34 | xfunc_error_retval = 2; /* SUSv3 requires > 1 for error. */ |
35 | |
36 | IF_INCLUDE_SUSv2(silent = getopt32(argv, "s");) |
37 | IF_INCLUDE_SUSv2(argv += optind;) |
38 | IF_NOT_INCLUDE_SUSv2(argv += 1;) |
39 | |
40 | /* gnu tty outputs a warning that it is ignoring all args. */ |
41 | bb_warn_ignoring_args(argv[0]); |
42 | |
43 | retval = EXIT_SUCCESS; |
44 | |
45 | s = xmalloc_ttyname(STDIN_FILENO); |
46 | if (s == NULL) { |
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. */ |
49 | s = "not a tty"; |
50 | retval = EXIT_FAILURE; |
51 | } |
52 | IF_INCLUDE_SUSv2(if (!silent) puts(s);) |
53 | IF_NOT_INCLUDE_SUSv2(puts(s);) |
54 | |
55 | fflush_stdout_and_exit(retval); |
56 | } |
57 |