/* vi: set sw=4 ts=4: */ /* * tty implementation for busybox * * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org> * * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */ /* BB_AUDIT SUSv3 compliant */ /* http://www.opengroup.org/onlinepubs/007904975/utilities/tty.html */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include "busybox.h" int tty_main(int argc, char **argv) { const char *s; int silent; /* Note: No longer relevant in SUSv3. */ int retval; bb_default_error_retval = 2; /* SUSv3 requires > 1 for error. */ silent = bb_getopt_ulflags(argc, argv, "s"); /* gnu tty outputs a warning that it is ignoring all args. */ bb_warn_ignoring_args(argc - optind); retval = 0; if ((s = ttyname(0)) == NULL) { /* According to SUSv3, ttyname can on fail with EBADF or ENOTTY. * We know the file descriptor is good, so failure means not a tty. */ s = "not a tty"; retval = 1; } if (!silent) { puts(s); } bb_fflush_stdout_and_exit(retval); }