/*  mingetty.c
 *
 *  Copyright (C) 1996 Florian La Roche  <laroche@redhat.com>
 *  Copyright (C) 2002, 2003 Red Hat, Inc
 *
 *  This getty can only be used as a small console getty. Look at mgetty
 *  for a real modem getty.
 *
 *  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.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <termios.h>
#include <string.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <signal.h>
#include <fcntl.h>
#include <stdarg.h>
#include <ctype.h>
#include <getopt.h>
#include <sys/param.h>
#include <syslog.h>
#include <sys/utsname.h>
#include <time.h>

/* name of this program (argv[0]) */
static char *progname;
/* on which tty line are we sitting? (e.g. tty1) */
static char *tty;
/* process and session ID of this program */
static pid_t pid, sid;
/* Do not call vhangup() on the tty. */
static int nohangup = 0;

/* error() - output error messages */
static void
error(const char *fmt, ...)
{
	va_list va_alist;

	va_start(va_alist, fmt);
	openlog(progname, LOG_PID, LOG_AUTH);
	vsyslog(LOG_ERR, fmt, va_alist);
	/* no need, we exit anyway: closelog (); */
	va_end(va_alist);
	sleep(5);
	exit(EXIT_FAILURE);
}

/* open_tty - set up tty as standard { input, output, error } */
static void
open_tty(void)
{
	struct sigaction sa, sa_old;
	char buf[40];
	int fd;

	/* Set up new standard input. */
	strcpy(buf, "/dev/");
	strcat(buf, tty);
	/* There is always a race between this reset and the call to
	   vhangup() that s.o. can use to get access to your tty. */
	if (chown(buf, 0, 0) || chmod(buf, 0600))
		if (errno != EROFS)
			error("%s: %s", tty, strerror(errno));

	sa.sa_handler = SIG_IGN;
	sa.sa_flags = 0;
	sigemptyset(&sa.sa_mask);
	sigaction(SIGHUP, &sa, &sa_old);

	/* vhangup() will replace all open file descriptors in the kernel
	   that point to our controlling tty by a dummy that will deny
	   further reading/writing to our device. It will also reset the
	   tty to sane defaults, so we don't have to modify the tty device
	   for sane settings. We also get a SIGHUP/SIGCONT.
	 */
	if ((fd = open(buf, O_RDWR, 0)) < 0)
		error("%s: cannot open tty: %s", tty, strerror(errno));
	if (!isatty(fd))
		error("%s: not a tty", tty);

	if (nohangup == 0) {
		if (vhangup())
			error("%s: vhangup() failed", tty);
		/* Get rid of the present stdout/stderr. */
		close(2);
		close(1);
		close(0);
		close(fd);
		if ((fd = open(buf, O_RDWR, 0)) != 0)
			error("%s: cannot open tty: %s", tty,
			      strerror(errno));
	}
	/* Set up stdin/stdout/stderr. */
	if (dup2(fd, 0) != 0 || dup2(fd, 1) != 1 || dup2(fd, 2) != 2)
		error("%s: dup2(): %s", tty, strerror(errno));
	if (fd > 2)
		close(fd);

	sigaction(SIGHUP, &sa_old, NULL);
}

void
get_logname(void)
{
	unsigned char c;
	struct termios org_opts, new_opts;
	int res = 0;

	tcflush(0, TCIFLUSH);           /* flush pending input */
	res = tcgetattr(STDIN_FILENO, &org_opts);
	memcpy(&new_opts, &org_opts, sizeof(new_opts));
	new_opts.c_lflag &=
		~(ICANON | ECHO | ECHOE | ECHOK | ECHONL | ECHOPRT | ECHOKE |
		  ICRNL);
	new_opts.c_cc[VMIN] = 1;
	tcsetattr(STDIN_FILENO, TCSANOW, &new_opts);


	if (read(0, &c, 1) < 1) {
		if (errno == EINTR || errno == EIO
		    || errno == ENOENT)
			exit(EXIT_SUCCESS);
		error("%s: read: %s", tty, strerror(errno));
	}
	exit(c);
}

int
main(int argc, char **argv)
{
	progname = argv[0];
	if (!progname)
		progname = "mingetty";

	pid = getpid();
	sid = getsid(0);
	putenv("TERM=linux");
	tty = strdup("tty1");

	open_tty();
	get_logname();
	return argc;
}