// connect.c - modem control (dial-up line) through a serial port
#include <signal.h>
#include <termios.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <unistd.h>

#define STDIN 0
#define STDOUT 1
#define STDERR 2
#define INCOMING 3
#define OUTGOING 4
#define FOREVER for(;;)
#define ESC 033
#define CR 015

struct fax {
	char *portname;
	char *tty;
	char *lock;
	char *phone_number;          
	unsigned short speed;
	unsigned short size;
	unsigned short mode;
	unsigned short startstop;
	};

struct fax ttystuff[] = {
	"office","/dev/ttyS0","/var/tmp/LOCKMODEM","ATDT6562258",B38400,
		CS8,CREAD|HUPCL,IXOFF,
	"westall","/dev/ttyS0","/var/tmp/LOCKMODEM","ATDT6565868",B38400,
		CS8,CREAD|HUPCL,IXOFF,
	"dept","/dev/ttyS0","/var/tmp/LOCKMODEM","ATDT6565879",B19200,
		CS8,CREAD|HUPCL|PARENB,IXOFF,
	0
	};

void incoming()
{ 
char  buf;

FOREVER 
	while(read(INCOMING, &buf, 1)) write(STDOUT, &buf, 1);
}

void outgoing()
{
char buf;

FOREVER 
	while(read(STDIN,&buf,1)) {
		// what's a good escape character?
		if (buf=='#') return;
		write(OUTGOING,&buf,1);
		}
}

void commanderror()
{
struct fax *ptr;

printf("syntax: connect <portname>\n");
printf("portnames available are:\n");
ptr=ttystuff;
while(ptr->portname){
	printf("%s\n",ptr->portname);
	ptr++;
	}
exit(1);
}

void dial(struct fax *ptr)
{
char c;
write(OUTGOING,ptr->phone_number,strlen(ptr->phone_number));
c=CR;
write(OUTGOING,&c,1);
}

void hangup()
{
char buf[4];
buf[0]='+'; buf[1]='+'; buf[2]='+'; buf[3]=CR;
sleep(2);
write(OUTGOING,buf,4);
buf[0]='A'; buf[1]='T'; buf[2]='H'; buf[3]=CR;
sleep(2);
write(OUTGOING,buf,4);
}

int main(int argc,char **argv)
{
struct termio modemport, controlport, saveport;
struct fax *ptr;
int pid,status;

if (argc != 2) commanderror();	// this is an exit 
ptr=ttystuff;
while(ptr->portname){
	if(strcmp(ptr->portname,argv[1])==0) break;
	ptr++;
	}
if(ptr->portname == 0) commanderror();
if(access(ptr->lock,F_OK) >= 0) {
	printf("port in use\n");
	exit(1);
	}
if(close(creat(ptr->lock,0)) < 0) {
	printf("system bug: \n");
	printf("cannot lock port\n");
	exit(1);
	}
if(open(ptr->tty,0) != INCOMING) {
	printf("cannot open %s for read\n",ptr->tty);
	unlink(ptr->lock);
	exit(1);
	}
if(open(ptr->tty,1) != OUTGOING) {
	printf("cannot open %s for write\n",ptr->tty);
	unlink(ptr->lock);
	exit(1);
	}

// set control terminal to raw mode 
ioctl(STDIN,TCGETA,&saveport);
controlport = saveport;
controlport.c_cflag &= ~(PARENB|CSIZE); 
controlport.c_cflag |= CS8;
controlport.c_lflag &= ~(ECHO|ICANON|ISIG);
controlport.c_oflag &= ~OPOST;
controlport.c_iflag |= IGNBRK;
controlport.c_iflag &= ~(ISTRIP|INLCR|IGNCR|ICRNL|IXON);

ioctl(STDIN,TCSETA,&controlport);
ioctl(STDOUT,TCSETA,&controlport);

// set io port 
ioctl(OUTGOING,TCGETA,&modemport);
modemport.c_cflag = ptr->speed;
modemport.c_cflag |= ptr->size;
modemport.c_cflag |= ptr->mode;
modemport.c_lflag &= ~ECHO;  // local echo can be annoying
modemport.c_iflag = ptr->startstop;

ioctl(OUTGOING,TCSETA,&modemport);
ioctl(INCOMING,TCSETA,&modemport);

switch(pid=fork())  {
	case  -1:  printf("OOPS  -  no fork!\n");
	  	    exit(1);

	case   0:  // child 
		   incoming();
		   break;

	default:   // parent  
		   dial(ptr);
		   outgoing();
		   kill(pid, SIGKILL);  // kill the kid 
		   while(wait(&status) != pid);
		   hangup();
		   // restore control terminal settings 
		   ioctl(STDIN,TCSETA,&saveport);
		   ioctl(STDOUT,TCSETA,&saveport);
		   unlink(ptr->lock);
		   break;
	}
return(0);
}