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 |