libpollcat/example/serial.c

/** minimal terminal using pollcat
 *
 *  This file is part of the Pollcat Library.
 *  Copyright (C) 2022 Expatria Technologies Inc.
 *  Contact: Morgan Hughes <morgan@expatria.ca>
 *
 *  The Pollcat Library is free software: you can redistribute it and/or modify it under
 *  the terms of the the GNU Lesser General Public License as published by the Free
 *  Software Foundation; either version 3 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 copies of the GNU General Public License and the GNU Lesser
 *  General Public License along with the Pollcat Library.  If not, see
 *  https://www.gnu.org/licenses/
 *
 *  vim:ts=4:noexpandtab
 */
#include <stdio.h>
#include <fcntl.h>
#include <ctype.h>
#include <errno.h>
#include <unistd.h>
#include <termios.h>

#include <pollcat.h>

#include "terminal.h"


static int fd;


static void service (struct pollcat *cat)
{
	char buff[4096];
	int  ret;
	int  idx;

	if ( !(pollcat_revents(fd) & POLLIN) )
		return;

	while ( (ret = read(fd, buff, sizeof(buff))) > 0 )
		tty_write(buff, ret);
}

static const struct pollcat_ops ops =
{
	.service = service,
};

static struct pollcat cat =
{
	.ops = &ops,
};

static int serial_fl;
static int serial_fd;
static struct termios serial_tio;

int serial_init (const char *node, const char *setup)
{
	speed_t  spd;
	char    *mod;

	if ( (fd = open(node, O_RDWR, 0)) < 0 )
		return -1;

	// set stdin nonblocking
	if ( (serial_fl = fcntl(fd, F_GETFL)) < 0 )
		return -1;
	if ( fcntl(fd, F_SETFL, serial_fl | O_NONBLOCK) < 0 )
		return -1;

	// set stdin nonblocking
	if ( (serial_fd = fcntl(fd, F_GETFD)) < 0 )
		return -1;
	if ( fcntl(fd, F_SETFD, serial_fd | FD_CLOEXEC) < 0 )
		return -1;

	// save old terminal modes and make raw
	if ( tcgetattr(fd, &serial_tio) )
		return -1;

	struct termios tio = serial_tio;
	cfmakeraw(&tio);

	switch ( strtoul(setup, &mod, 10) )
	{
		case 50:     spd = B50;     break;
		case 75:     spd = B75;     break;
		case 110:    spd = B110;    break;
		case 134:    spd = B134;    break;
		case 150:    spd = B150;    break;
		case 200:    spd = B200;    break;
		case 300:    spd = B300;    break;
		case 600:    spd = B600;    break;
		case 1200:   spd = B1200;   break;
		case 1800:   spd = B1800;   break;
		case 2400:   spd = B2400;   break;
		case 4800:   spd = B4800;   break;
		case 9600:   spd = B9600;   break;
		case 19200:  spd = B19200;  break;
		case 38400:  spd = B38400;  break;
		case 57600:  spd = B57600;  break;
		case 115200: spd = B115200; break;
#ifdef B230400
		case 230400: spd = B230400; break;
#endif
#ifdef B460800
		case 460800: spd = B460800; break;
#endif
#ifdef B500000
		case 500000: spd = B500000; break;
#endif
#ifdef B576000
		case 576000: spd = B576000; break;
#endif
#ifdef B921600
		case 921600: spd = B921600; break;
#endif
#ifdef B1000000
		case 1000000: spd = B1000000; break;
#endif
#ifdef B1152000
		case 1152000: spd = B1152000; break;
#endif
#ifdef B1500000
		case 1500000: spd = B1500000; break;
#endif
#ifdef B2000000
		case 2000000: spd = B2000000; break;
#endif
#ifdef B2500000
		case 2500000: spd = B2500000; break;
#endif
#ifdef B3000000
		case 3000000: spd = B3000000; break;
#endif
#ifdef B3500000
		case 3500000: spd = B3500000; break;
#endif
#ifdef B4000000
		case 4000000: spd = B4000000; break;
#endif
		default:
			errno = EINVAL;
			return -1;
	}
	if ( cfsetispeed(&tio, spd) || cfsetospeed(&tio, spd) )
		return -1;

	while ( *mod )
	{
		switch ( toupper(*mod) )
		{
			// data bits
			case '8': tio.c_cflag &= ~CSIZE; tio.c_cflag |= CS8; break;
			case '7': tio.c_cflag &= ~CSIZE; tio.c_cflag |= CS7; break;
			case '6': tio.c_cflag &= ~CSIZE; tio.c_cflag |= CS6; break;
			case '5': tio.c_cflag &= ~CSIZE; tio.c_cflag |= CS5; break;

			// stop bits
			case '2': tio.c_cflag |=  CSTOPB; break;
			case '1': tio.c_cflag &= ~CSTOPB; break;

			// no parity
			case 'N':
				tio.c_iflag |= IGNPAR;
				tio.c_iflag &= ~INPCK;
				tio.c_cflag &= ~(PARENB | PARODD | CMSPAR);
				break;

			// odd parity
			case 'O':
				tio.c_iflag |= INPCK | PARMRK;
				tio.c_iflag &= ~IGNPAR;
				tio.c_cflag |= PARENB | PARODD;
				tio.c_cflag &= ~CMSPAR;
				break;

			// even parity
			case 'E':
				tio.c_iflag |= INPCK | PARMRK;
				tio.c_iflag &= ~IGNPAR;
				tio.c_cflag |= PARENB;
				tio.c_cflag &= ~(PARODD | CMSPAR);
				break;

			// mark parity
			case 'M':
				tio.c_iflag |= INPCK | PARMRK;
				tio.c_iflag &= ~IGNPAR;
				tio.c_cflag |= PARENB | CMSPAR | PARODD;
				break;

			// space parity
			case 'S':
				tio.c_iflag |= INPCK | PARMRK;
				tio.c_iflag &= ~IGNPAR;
				tio.c_cflag |= PARENB | CMSPAR;
				tio.c_cflag &= ~PARODD;
				break;

			default:
				errno = EINVAL;
				return -1;
		}
		mod++;
	}

	if ( tcsetattr(fd, TCSANOW, &tio) )
		return -1;

	pollcat_fd_add(fd, POLLIN);
	pollcat_iter_add(&cat);
	return 0;
}


void serial_done (void)
{
	pollcat_iter_remove(&cat);
	pollcat_fd_remove(fd);

	if ( fcntl(fd, F_SETFL, serial_fl) < 0 )
		perror("fcntl");

	if ( fcntl(fd, F_SETFD, serial_fd) < 0 )
		perror("fcntl");

	if ( tcsetattr(fd, TCSANOW, &serial_tio) )
		perror("tcsetattr");

	close(fd);
}

void serial_write (const void *buff, int len)
{
	write(fd, buff, len);
}