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 (3.6 kb)" 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_NOFORK(tty, tty, BB_DIR_USR_BIN, BB_SUID_DROP, tty)) 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 37int tty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 38int 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