/* $OpenBSD: cu.c,v 1.3 2012/07/10 08:42:43 nicm Exp $ */

/*
 * Copyright (c) 2012 Nicholas Marriott <nicm@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/ioctl.h>

#include <err.h>
#include <event.h>
#include <fcntl.h>
#include <getopt.h>
#include <paths.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

#include "cu.h"

extern char		*__progname;

struct termios		 saved_tio;
struct bufferevent	*input_ev;
struct bufferevent	*output_ev;
int			 line_fd;
struct bufferevent	*line_ev;
struct event		 sigterm_ev;
enum {
	STATE_NONE,
	STATE_NEWLINE,
	STATE_TILDE
} last_state = STATE_NEWLINE;

__dead void	usage(void);
void		signal_event(int, short, void *);
void		stream_read(struct bufferevent *, void *);
void		stream_error(struct bufferevent *, short, void *);
void		line_read(struct bufferevent *, void *);
void		line_error(struct bufferevent *, short, void *);

__dead void
usage(void)
{
	fprintf(stderr, "usage: %s [-l line] [-s speed]\n", __progname);
	exit(1);
}

int
main(int argc, char **argv)
{
	const char	*line, *errstr;
	char		*tmp;
	int		 opt, speed, i, ch;
	static char	 sbuf[12];

	line = "/dev/cua00";
	speed = 9600;

	/*
	 * Convert obsolescent -### speed to modern -s### syntax which getopt()
	 * can handle.
	 */
	for (i = 1; i < argc; i++) {
		if (argv[i][0] == '-') {
			switch (argv[i][1]) {
			case '0': case '1': case '2': case '3': case '4':
			case '5': case '6': case '7': case '8': case '9':
				ch = snprintf(sbuf, sizeof(sbuf), "-s%s",
				    &argv[i][1]);
				if (ch <= 0 || ch >= (int)sizeof(sbuf)) {
					errx(1, "invalid speed: %s",
					    &argv[i][1]);
				}
				argv[i] = sbuf;
				break;
			case '-':
				/* if we get "--" stop processing args */
				if (argv[i][2] == '\0')
					goto getopt;
				break;
			}
		}
	}

getopt:
	while ((opt = getopt(argc, argv, "l:s:")) != -1) {
		switch (opt) {
		case 'l':
			line = optarg;
			break;
		case 's':
			speed = strtonum(optarg, 0, UINT_MAX, &errstr);
			if (errstr != NULL)
				errx(1, "speed is %s: %s", errstr, optarg);
			break;
		default:
			usage();
		}
	}
	argc -= optind;
	argv += optind;
	if (argc != 0)
		usage();

	if (strchr(line, '/') == NULL) {
		if (asprintf(&tmp, "%s%s", _PATH_DEV, line) == -1)
			err(1, "asprintf");
		line = tmp;
	}

	line_fd = open(line, O_RDWR);
	if (line_fd < 0)
		err(1, "open(\"%s\")", line);
	if (ioctl(line_fd, TIOCEXCL) != 0)
		err(1, "ioctl(TIOCEXCL)");

	if (set_line(speed) != 0)
		exit(1);

	if (isatty(STDIN_FILENO) && tcgetattr(STDIN_FILENO, &saved_tio) != 0)
		err(1, "tcgetattr");

	event_init();

	signal_set(&sigterm_ev, SIGTERM, signal_event, NULL);
	signal_add(&sigterm_ev, NULL);
	if (signal(SIGINT, SIG_IGN) == SIG_ERR)
		err(1, "signal");
	if (signal(SIGQUIT, SIG_IGN) == SIG_ERR)
		err(1, "signal");

	set_termios();

	/* stdin and stdout get separate events */
	input_ev = bufferevent_new(STDIN_FILENO, stream_read, NULL,
	    stream_error, NULL);
	bufferevent_enable(input_ev, EV_READ);
	output_ev = bufferevent_new(STDOUT_FILENO, NULL, NULL, stream_error,
	    NULL);
	bufferevent_enable(output_ev, EV_WRITE);

	line_ev = bufferevent_new(line_fd, line_read, NULL, line_error,
	    NULL);
	bufferevent_enable(line_ev, EV_READ|EV_WRITE);

	printf("Connected (speed %u)\r\n", speed);
	event_dispatch();

	if (isatty(STDIN_FILENO))
		tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_tio);
	printf("\r\n[EOT]\n");

	exit(0);
}

void
signal_event(int fd, short events, void *data)
{
	if (isatty(STDIN_FILENO))
		tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_tio);
	printf("\r\n[SIG%s]\n", sys_signame[fd]);

	exit(0);
}

void
set_termios(void)
{
	struct termios tio;

	if (!isatty(STDIN_FILENO))
		return;

	memcpy(&tio, &saved_tio, sizeof(tio));
	tio.c_lflag &= ~(ICANON|IEXTEN|ECHO);
	tio.c_iflag &= ~(INPCK|ICRNL);
	tio.c_oflag &= ~OPOST;
	tio.c_cc[VMIN] = 1;
	tio.c_cc[VTIME] = 0;
	tio.c_cc[VDISCARD] = _POSIX_VDISABLE;
	tio.c_cc[VDSUSP] = _POSIX_VDISABLE;
	tio.c_cc[VINTR] = _POSIX_VDISABLE;
	tio.c_cc[VLNEXT] = _POSIX_VDISABLE;
	tio.c_cc[VQUIT] = _POSIX_VDISABLE;
	tio.c_cc[VSUSP] = _POSIX_VDISABLE;
	if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio) != 0)
		err(1, "tcsetattr");
}

void
restore_termios(void)
{
	if (!isatty(STDIN_FILENO))
		return;

	if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_tio) != 0)
		err(1, "tcsetattr");
}

int
set_line(int speed)
{
	struct termios	 tio;

	cfmakeraw(&tio);
	tio.c_iflag = 0;
	tio.c_oflag = 0;
	tio.c_lflag = 0;
	tio.c_cflag = CREAD|CS8;
	tio.c_cc[VMIN] = 1;
	tio.c_cc[VTIME] = 0;
	cfsetspeed(&tio, speed);
	if (tcsetattr(line_fd, TCSAFLUSH, &tio) != 0) {
		warn("tcsetattr");
		return (-1);
	}
	return (0);
}

void
stream_read(struct bufferevent *bufev, void *data)
{
	char	*new_data, *ptr;
	size_t	 new_size;
	int	 state_change;

	new_data = EVBUFFER_DATA(input_ev->input);
	new_size = EVBUFFER_LENGTH(input_ev->input);
	if (new_size == 0)
		return;

	state_change = isatty(STDIN_FILENO);
	for (ptr = new_data; ptr < new_data + new_size; ptr++) {
		switch (last_state) {
		case STATE_NONE:
			if (state_change && *ptr == '\r')
				last_state = STATE_NEWLINE;
			break;
		case STATE_NEWLINE:
			if (state_change && *ptr == '~') {
				last_state = STATE_TILDE;
				continue;
			}
			if (*ptr != '\r')
				last_state = STATE_NONE;
			break;
		case STATE_TILDE:
			do_command(*ptr);
			last_state = STATE_NEWLINE;
			continue;
		}

		bufferevent_write(line_ev, ptr, 1);
	}

	evbuffer_drain(input_ev->input, new_size);
}

void
stream_error(struct bufferevent *bufev, short what, void *data)
{
	event_loopexit(NULL);
}

void
line_read(struct bufferevent *bufev, void *data)
{
	char	*new_data;
	size_t	 new_size;

	new_data = EVBUFFER_DATA(line_ev->input);
	new_size = EVBUFFER_LENGTH(line_ev->input);
	if (new_size == 0)
		return;

	bufferevent_write(output_ev, new_data, new_size);

	evbuffer_drain(line_ev->input, new_size);
}

void
line_error(struct bufferevent *bufev, short what, void *data)
{
	event_loopexit(NULL);
}

/* Expands tildes in the file name. Based on code from ssh/misc.c. */
char *
tilde_expand(const char *filename1)
{
	const char	*filename, *path;
	char		 user[128], ret[MAXPATHLEN], *out;
	struct passwd	*pw;
	u_int		 len, slash;

	if (*filename1 != '~')
		goto no_change;
	filename = filename1 + 1;

	path = strchr(filename, '/');
	if (path != NULL && path > filename) {		/* ~user/path */
		slash = path - filename;
		if (slash > sizeof(user) - 1)
			goto no_change;
		memcpy(user, filename, slash);
		user[slash] = '\0';
		if ((pw = getpwnam(user)) == NULL)
			goto no_change;
	} else if ((pw = getpwuid(getuid())) == NULL)	/* ~/path */
		goto no_change;

	if (strlcpy(ret, pw->pw_dir, sizeof(ret)) >= sizeof(ret))
		goto no_change;

	/* Make sure directory has a trailing '/' */
	len = strlen(pw->pw_dir);
	if ((len == 0 || pw->pw_dir[len - 1] != '/') &&
	    strlcat(ret, "/", sizeof(ret)) >= sizeof(ret))
		goto no_change;

	/* Skip leading '/' from specified path */
	if (path != NULL)
		filename = path + 1;
	if (strlcat(ret, filename, sizeof(ret)) >= sizeof(ret))
		goto no_change;

	out = strdup(ret);
	if (out == NULL)
		err(1, "strdup");
	return (out);

no_change:
	out = strdup(filename1);
	if (out == NULL)
		err(1, "strdup");
	return (out);
}