//tell DGPS to start or stop logging
// args: [start,stop] filename
// KM July 2003
// version 1.1
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#define BYTE unsigned char
#define SERIALPORT "/dev/ttyS0"
#define LOGFILE "/home/km/incoming/gps.log"

// GLOBAL variables for simplicity
int serialport; // serial port 
FILE *logfd; // log file 
char mesg[512]; // somewhere to make logfile strings!
//---------------------- HELPERS-------------------------
BYTE getbyte () 
{
  BYTE byte;
  read (serialport, &byte, 1);
  return byte;
}

// write a byte
BYTE putbyte(BYTE b)
{
        return(write(serialport, &b, 1));
}

// write a string
int putstring(char *s)
{
        int l = strlen(s);
//log(s);
        if ( write(serialport, s, l) != l)
                return(-1);
        else return(0);
}

// print message to log file 
void logfile(char *str)
{
fprintf(logfd, str);
fflush(logfd);
}
// print error message to log file and exit
erexit(char *str)
{
fprintf(logfd, str);
// exit is a bit severe?
exit(1);
}
	
//-------------------- INITIALISE-----------------
// open serial port for raw byte transfers
// open log file
initialise()
{
	struct termios term;

	// open log file for appending
	logfd = fopen(LOGFILE, "a");
	if( logfd == NULL) erexit("failed to open log file!");

	// now the serial port
serialport = open (SERIALPORT, O_RDWR | O_NOCTTY );
if (serialport == -1)
      erexit ("can not open serial port!\n");

if( tcgetattr(serialport, &term) == -1)  erexit("getattr failed!");
// set BAUD rate
cfsetospeed(&term, B38400);
cfsetispeed(&term, B38400);
cfmakeraw(&term);
// Set the serial port mode NOW
if( tcsetattr(serialport, TCSANOW, &term) == -1) erexit("setattr failed!");

logfile("openned GPS port OK\n");
}

//-------------------- MAIN------------------------
main (int argc, char **argv) 
{
	int n;
	BYTE byte;
char command[512];
  
initialise();

if( !strcmp(argv[1], "-start")){
	// set the filename
	sprintf(command, "create,%s\n",argv[2]);
	logfile(command);
	putstring(command);
	// start logging
	sprintf(command, "em,/cur/log,def\n");
	logfile(command);
	putstring(command);
	}
else if(!strcmp(argv[1],"-stop")){
	// stop logging
	sprintf(command, "dm,/cur/log\n");
	putstring(command);
	logfile(command);
	}

fclose(logfd);
close(serialport);
}