/* vi: set sw=4 ts=4: *//* * Utility routines. * * Copyright (C) many different people.  If you wrote this, please * acknowledge your work. * * 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 <stdio.h>#include <errno.h>#include <fcntl.h>#include <unistd.h>#include <sys/ioctl.h>#include "libbb.h"/* From <linux/kd.h> */ static const int KDGKBTYPE = 0x4B33;  /* get keyboard type */static const int KB_84 = 0x01;static const int KB_101 = 0x02;    /* this is what we always answer */int is_a_console(int fd){	char arg;	arg = 0;	return (ioctl(fd, KDGKBTYPE, &arg) == 0			&& ((arg == KB_101) || (arg == KB_84)));}static int open_a_console(char *fnam){	int fd;	/* try read-only */	fd = open(fnam, O_RDWR);	/* if failed, try read-only */	if (fd < 0 && errno == EACCES)		fd = open(fnam, O_RDONLY);	/* if failed, try write-only */	if (fd < 0 && errno == EACCES)		fd = open(fnam, O_WRONLY);	/* if failed, fail */	if (fd < 0)		return -1;	/* if not a console, fail */	if (!is_a_console(fd)) {		close(fd);		return -1;	}	/* success */	return fd;}/* * Get an fd for use with kbd/console ioctls. * We try several things because opening /dev/console will fail * if someone else used X (which does a chown on /dev/console). * * if tty_name is non-NULL, try this one instead. */int get_console_fd(void){	int fd;	if (-1 == (fd = open_a_console("/dev/console")))		return -1;	else		return fd;	fd = open_a_console(CURRENT_TTY);	if (fd >= 0)		return fd;	fd = open_a_console(CURRENT_VC);	if (fd >= 0)		return fd;	fd = open_a_console(CONSOLE_DEV);	if (fd >= 0)		return fd;	for (fd = 0; fd < 3; fd++)		if (is_a_console(fd))			return fd;	error_msg("Couldn't get a file descriptor referring to the console");	return -1;					/* total failure */}/* END CODE *//*Local Variables:c-file-style: "linux"c-basic-offset: 4tab-width: 4End:*/