/*-
 * Copyright (c) 2001 Hellmuth Michaelis. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *---------------------------------------------------------------------------
 *
 *	nifmon - main
 *	-------------
 *
 *      last edit-date: [Wed May  2 16:32:52 2001]
 *
 *---------------------------------------------------------------------------*/

#define MAIN
#include "nifmon.h"
#undef MAIN

static pid_t pid;

/*---------------------------------------------------------------------------
 *	Display usage and exit
 *---------------------------------------------------------------------------*/
static void
usage()
{
	fprintf(stderr, "\n");
	fprintf(stderr, "nifmon -b -e <expr> -i <if> -r <tty> -t <termtype> (V%d.%d)\n", VERSION, RELEASE);
	fprintf(stderr, "       -b        run in background [needs -r and -t]\n");
	fprintf(stderr, "       -e <expr> tcpdump expression\n");
	fprintf(stderr, "       -i <if>   monitor interface <if>, default lo0\n");
	fprintf(stderr, "       -r <tty>  redirect output to device <tty>\n");
	fprintf(stderr, "       -t <term> terminal type for device <tty>\n");
	exit(1);
}

/*---------------------------------------------------------------------------
 *	Parse command line, startup monitor client
 *---------------------------------------------------------------------------*/
int
main(int argc, char **argv)
{
	int i;
	char *netif = "lo0";
	char *expression = "";
	
	while ((i = getopt(argc, argv, "be:i:r:t:")) != -1)
	{
		switch (i)
		{
			case 'b':
				background = 1;
				break;

			case 'e':
				expression = optarg;
				break;

			case 'i':
				netif = optarg;
				break;

			case 'r':
				rdev = optarg;
				has_rdev = 1;
				break;

			case 't':
				term = optarg;
				has_term = 1;
				break;
			default:
				usage();
				break;
		}
	}

	if (background)
	{
		if (has_rdev == 0 || has_term == 0)
		{
			fprintf(stderr, "-b option needs both -t and -r!\n");
			exit(1);
		}
	}

	/* only root is able to open /dev/bpfN */

	if (getuid() != 0)
	{
		fprintf(stderr,
			"You must be superuser (root) to run this program\n");
		exit(1);
	}

	sprintf(pidfile, "%s-%s%s", PIDFIL, netif, PIDPID);
	
	if (background)
	{
		check_pid(pidfile);
		daemonize();
		write_pid(pidfile);
	}

	signal(SIGHUP,  do_exit);
	signal(SIGINT,  do_exit);
	signal(SIGQUIT, do_exit);
	signal(SIGTERM, do_exit);
	signal(SIGUSR1, do_exit);
	signal(SIGUSR2, do_exit);
	
	init_interface(netif);

	init_screen(netif);

	pfp = mpopen(netif, expression);

	if (pfp == NULL)
	{
		perror("mpopen");
		do_exit(1);
	}

	for (;;)
	{
		fd_set set;
		struct timeval timeout;
		int ret;
		int high_selfd;

		FD_ZERO(&set);

		FD_SET(fileno(stdin), &set);
		high_selfd = fileno(stdin);

		FD_SET(fileno(pfp), &set);
		high_selfd = fileno(pfp);

		timeout.tv_sec = 1;
		timeout.tv_usec = 0;

		ret = select(high_selfd + 1, &set, NULL, NULL, &timeout);

		if (ret > 0)
		{
			if (FD_ISSET(fileno(stdin), &set))
				kbdrdhdl();

			if (FD_ISSET(fileno(pfp), &set))
				loghdl(pfp);
		}
		update_interface(netif);
	}
}

/*---------------------------------------------------------------------------*
 *	program exit
 *---------------------------------------------------------------------------*/
void
do_exit(int exitval)
{
	mpclose(pfp);
	if (curses_ready)
		endwin();
	unlink(pidfile);
	exit(exitval);
}

/*---------------------------------------------------------------------------*
 *	open pipe to tcpdump
 *---------------------------------------------------------------------------*/
FILE *
mpopen(char *interface, char *expression)
{
	FILE *fp;
	int pdes[2];
	char *argv[5];

	if (pipe(pdes) < 0)
		return (NULL);

	argv[0] = TCPDUMP;
	argv[1] = TCPDUMPFLAGS;
	argv[2] = interface;
	argv[3] = expression;
	argv[4] = NULL;

	switch (pid = vfork())
	{
		case -1:	/* Error. */
			(void) close(pdes[0]);
			(void) close(pdes[1]);
			return (NULL);

		case 0:	/* Child. */
			(void) close(pdes[0]);

			if (pdes[1] != STDOUT_FILENO)
			{
				(void) dup2(pdes[1], STDOUT_FILENO);
				(void) close(pdes[1]);
			}
/*XXX*/			close(STDERR_FILENO);

			execv(TCPDUMPPATH, argv);
			_exit(127);
	}

	/* Parent */

	fp = fdopen(pdes[0], "r");
	(void) close(pdes[1]);

	return (fp);
}

/*---------------------------------------------------------------------------*
 *	close pipe and terminate tcpdump
 *---------------------------------------------------------------------------*/
int
mpclose(FILE * fp)
{
	int pstat;
	pid_t mpid;

	(void) fclose(fp);

	kill(pid, SIGTERM);

	do
	{
		mpid = wait4(pid, &pstat, 0, (struct rusage *) 0);
	}
	while (mpid == -1 && errno == EINTR);

	return (mpid == -1 ? -1 : pstat);
}