blob: 359e5bc9314b1a8a416f967eb34ebfa8d192cf30
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 | //config:config TTY |
10 | //config: bool "tty" |
11 | //config: default y |
12 | //config: help |
13 | //config: tty is used to print the name of the current terminal to |
14 | //config: standard output. |
15 | |
16 | //applet:IF_TTY(APPLET(tty, BB_DIR_USR_BIN, BB_SUID_DROP)) |
17 | |
18 | //kbuild:lib-$(CONFIG_TTY) += tty.o |
19 | |
20 | /* BB_AUDIT SUSv4 compliant */ |
21 | /* http://www.opengroup.org/onlinepubs/9699919799/utilities/tty.html */ |
22 | |
23 | //usage:#define tty_trivial_usage |
24 | //usage: "" |
25 | //usage:#define tty_full_usage "\n\n" |
26 | //usage: "Print file name of stdin's terminal" |
27 | //usage: IF_INCLUDE_SUSv2( "\n" |
28 | //usage: "\n -s Print nothing, only return exit status" |
29 | //usage: ) |
30 | //usage: |
31 | //usage:#define tty_example_usage |
32 | //usage: "$ tty\n" |
33 | //usage: "/dev/tty2\n" |
34 | |
35 | #include "libbb.h" |
36 | |
37 | int tty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
38 | int tty_main(int argc UNUSED_PARAM, char **argv) |
39 | { |
40 | const char *s; |
41 | IF_INCLUDE_SUSv2(int silent;) /* Note: No longer relevant in SUSv3. */ |
42 | int retval; |
43 | |
44 | xfunc_error_retval = 2; /* SUSv3 requires > 1 for error. */ |
45 | |
46 | IF_INCLUDE_SUSv2(silent = getopt32(argv, "s");) |
47 | IF_INCLUDE_SUSv2(argv += optind;) |
48 | IF_NOT_INCLUDE_SUSv2(argv += 1;) |
49 | |
50 | /* gnu tty outputs a warning that it is ignoring all args. */ |
51 | bb_warn_ignoring_args(argv[0]); |
52 | |
53 | retval = EXIT_SUCCESS; |
54 | |
55 | s = xmalloc_ttyname(STDIN_FILENO); |
56 | if (s == NULL) { |
57 | /* According to SUSv3, ttyname can fail with EBADF or ENOTTY. |
58 | * We know the file descriptor is good, so failure means not a tty. */ |
59 | s = "not a tty"; |
60 | retval = EXIT_FAILURE; |
61 | } |
62 | IF_INCLUDE_SUSv2(if (!silent) puts(s);) |
63 | IF_NOT_INCLUDE_SUSv2(puts(s);) |
64 | |
65 | fflush_stdout_and_exit(retval); |
66 | } |
67 |