/*
* AUTHOR: Sven Goldt (goldt@math.tu-berlin.de)
*
* 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.
*
*/
/*
This is like all programs in the Linux Programmer's Guide meant
as a simple practical demonstration.
It can be used as a base for a real terminal program.
*/
#include <termios.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/signal.h>
#define BAUDRATE B38400
#define MODEMDEVICE "/dev/ttyS1"
#define ENDMINITERM 2 /* ctrl-b to quit miniterm */
#define _POSIX_SOURCE 1 /* POSIX compliant source */
#define FALSE 0
#define TRUE 1
volatile int STOP=FALSE;
void child_handler(int s)
{
STOP=TRUE;
}
main()
{
int fd,c;
struct termios oldtio,newtio,oldstdtio,newstdtio;
struct sigaction sa;
/*
Open modem device for reading and writing and not as controlling tty
because we don't want to get killed if linenoise sends CTRL-C.
*/
fd = open(MODEMDEVICE, O_RDWR | O_NOCTTY);
if (fd <0) {perror(MODEMDEVICE); exit(-1); }
tcgetattr(fd,&oldtio); /* save current modem settings */
/*
Set bps rate and hardware flow control and 8n1 (8bit,no parity,1 stopbit).
Also don't hangup automatically and ignore modem status.
Finally enable receiving characters.
*/
newtio.c_cflag = BAUDRATE | CRTSCTS | CS8 | CLOCAL | CREAD;
/*
Ignore bytes with parity errors and make terminal raw and dumb.
*/
newtio.c_iflag = IGNPAR;
/*
Raw output.
*/
newtio.c_oflag = 0;
/*
Don't echo characters because if you connect to a host it or your
modem will echo characters for you. Don't generate signals.
*/
newtio.c_lflag = 0;
/* blocking read until 1 char arrives */
newtio.c_cc[VMIN]=1;
newtio.c_cc[VTIME]=0;
/* now clean the modem line and activate the settings for modem */
tcflush(fd, TCIFLUSH);
tcsetattr(fd,TCSANOW,&newtio);
/*
Strange, but if you uncomment this command miniterm will not work
even if you stop canonical mode for stdout. This is a linux bug.
*/
tcsetattr(1,TCSANOW,&newtio); /* stdout settings like modem settings */
/* next stop echo and buffering for stdin */
tcgetattr(0,&oldstdtio);
tcgetattr(0,&newstdtio); /* get working stdtio */
newstdtio.c_lflag &= ~(ICANON | ECHO);
tcsetattr(0,TCSANOW,&newstdtio);
/* terminal settings done, now handle in/ouput */
switch (fork())
{
case 0: /* child */
/* user input */
close(1); /* stdout not needed */
for (c=getchar(); c!= ENDMINITERM ; c=getchar()) write(fd,&c,1);
tcsetattr(fd,TCSANOW,&oldtio); /* restore old modem setings */
tcsetattr(0,TCSANOW,&oldstdtio); /* restore old tty setings */
close(fd);
exit(0); /* will send a SIGCHLD to the parent */
break;
case -1:
perror("fork");
tcsetattr(fd,TCSANOW,&oldtio);
close(fd);
exit(-1);
default: /* parent */
close(0); /* stdin not needed */
sa.sa_handler = child_handler;
sa.sa_flags = 0;
sigaction(SIGCHLD,&sa,NULL); /* handle dying child */
while (STOP==FALSE) /* modem input handler */
{
read(fd,&c,1); /* modem */
write(1,&c,1); /* stdout */
}
wait(NULL); /* wait for child to die or it will become a zombie */
break;
}
}
