/*
 *  xtty by Davide Libenzi (trivial console to peek/poke to tty-like devices)
 *  Copyright (C) 2005  Davide Libenzi
 *
 *  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
 *
 *  Davide Libenzi <davidel@xmailserver.org>
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/poll.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>


#define STD_POLL_TIMEO (1 * 1000)


static void xtty_usage(char const *prg) {

	fprintf(stderr, "use: %s --dev DEV [--at-mode] [--unbuf] [--help]\n", prg);
}

static char *xtty_tr(char *str, int n, char const *imap,
		     char const *omap, int mn) {
	int i;
	char const *tmp;

	for (i = 0; i < n; i++)
		if ((tmp = (char *) memchr(imap, str[i], mn)) != NULL)
			str[i] = omap[tmp - imap];

	return str;
}

static int xtty_setnobuf(int fd) {
	struct termios ttysts;

	if (tcgetattr(fd, &ttysts)) {
		perror("tcgetattr");
		return -1;
	}

	/*
	 * Disable canonical mode, and set buffer size to 1 byte.
	 */
	ttysts.c_lflag &= ~ICANON;
	ttysts.c_cc[VTIME] = 0;
	ttysts.c_cc[VMIN] = 1;
	if (tcsetattr(fd, TCSANOW, &ttysts)) {
		perror("tcgetattr");
		return -1;
	}

	return 0;
}

int main(int ac, char **av) {
	int i, fd, rdbytes, timeo = STD_POLL_TIMEO, atmode = 0;
	char const *dev = NULL;
	struct pollfd pfds[2];
	char buf[1024];

	for (i = 1; i < ac; i++) {
		if (!strcmp(av[i], "--dev")) {
			if (++i < ac)
				dev = av[i];
		}
		else if (!strcmp(av[i], "--at-mode"))
			atmode++;
		else if (!strcmp(av[i], "--unbuf"))
			xtty_setnobuf(0);
		else if (!strcmp(av[i], "--help")) {
			xtty_usage(av[0]);
			return 1;
		}
	}
	if (dev == NULL) {
		xtty_usage(av[0]);
		return 1;
	}
	if ((fd = open(dev, O_RDWR)) == -1) {
		perror(dev);
		return 2;
	}
	for (;;) {
		pfds[0].fd = fd;
		pfds[0].events = POLLIN;
		pfds[0].revents = 0;
		pfds[1].fd = 0;
		pfds[1].events = POLLIN;
		pfds[1].revents = 0;
		poll(pfds, 2, timeo);
		if (pfds[0].revents & POLLIN) {
			if ((rdbytes = read(pfds[0].fd, buf,
					    sizeof(buf))) > 0)
				write(1, buf, rdbytes);
			else if (rdbytes == 0)
				break;
		}
		if (pfds[1].revents & POLLIN) {
			if ((rdbytes = read(pfds[1].fd, buf,
					    sizeof(buf))) > 0) {
				if (atmode)
					xtty_tr(buf, rdbytes, "\n", "\r", 1);
				write(fd, buf, rdbytes);
			}
			else if (rdbytes == 0)
				break;
		}
	}
	close(fd);

	return 0;
}