busybox/tty.c

/* vi: set sw=4 ts=4: */
/*
 * Mini tty implementation for busybox
 *
 * Copyright (C) 2000  Edward Betts <edward@debian.org>.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include "internal.h"
#include <stdio.h>
#include <sys/types.h>

static const char tty_usage[] = "tty\n"
#ifndef BB_FEATURE_TRIVIAL_HELP
	"\nPrint the file name of the terminal connected to standard input.\n\n"
	"Options:\n"
	"\t-s\tprint nothing, only return an exit status\n"
#endif
	;

extern int tty_main(int argc, char **argv)
{
	char *tty;

	if (argc > 1) {
		if (argv[1][0] != '-' || argv[1][1] != 's')
			usage(tty_usage);
	} else {
		tty = ttyname(0);
		if (tty)
			puts(tty);
		else
			puts("not a tty");
	}
	exit(isatty(0) ? TRUE : FALSE);
}