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Once we've set up termios, lines need to be \r\n terminated, and we need
to reset termios before exiting. So add custom versions of err(),
errx(), warn(), warnx() to handle this.

/* $OpenBSD: cu.c,v 1.4 2012/07/10 10:28:05 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)
		err(1, "tcsetattr");

	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(); /* after this use cu_err and friends */

	/* 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)
		cu_err(1, "tcsetattr");
}

void
restore_termios(void)
{
	if (isatty(STDIN_FILENO))
		tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_tio);
}

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)
		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)
		cu_err(1, "strdup");
	return (out);

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