Saving parameters after shut down

component paramsaver;

pin in float invalue1                "Receives value1 to update to";
pin out float outvalue1              "Sends value1";
pin in float invalue2                "Receives value2 to update to";
pin out float outvalue2              "Sends value2";
pin in float invalue3                "Receives value3 to update to";
pin out float outvalue3              "Sends value3";

pin in bit readtrigger = 0          "signal to read from file";
pin in bit writetrigger = 0         "signal to write to file";

option singleton yes;               
option userspace yes;

author "ArcEye <arceyeATmgwareDOTcoDOTuk>";
license "GPL";
;;

#include <stdio.h>    /* Standard input/output definitions */
#include <stdlib.h> 
#include <stdint.h>   /* Standard types */
#include <string.h>   /* String function definitions */
#include <unistd.h>   /* UNIX standard function definitions */
#include <fcntl.h>    /* File control definitions */
#include <errno.h>    /* Error number definitions */
#include <signal.h>
#include <pwd.h>

int done = 0;

void adios(int sig) { done = 1; }


void user_mainloop(void)
{
char line[80];
char filepath[80];
float val1, val2, val3;
int read, write;

struct passwd *pw = getpwuid(getuid());
const char *homedir = pw->pw_dir;

    sprintf(filepath, "%s/linuxcnc/param.sav", homedir);

    read = write = 0;
    
    signal(SIGINT, adios);
    signal(SIGTERM, adios);
      
    while(!done)
        {
        usleep(250000);
        
        FOR_ALL_INSTS()  
            { 
            if(!readtrigger && read) read = 0;
            if(!writetrigger && write) write = 0;
            
            if(readtrigger && !read)
            // reads the file and sets the out pins to the values read
            // connect to the spinbox param-pin which will update the widget display
                {
                FILE *fp1;
                fp1 = fopen(filepath, "r");
                fgets(line, sizeof(line), fp1);
                // only write to pins if sscanf was sucessful 
                if (sscanf(line, "%f %f %f ", &val1, &val2, &val3) != 1)
                    outvalue1 = val1; outvalue2 = val2; outvalue3 = val3;
                fclose(fp1);
                read = 1;  
                }
            else if(writetrigger && ! write)
            // reads the values from the in pins and write to file
            // connect to the spinbox out pin
                {
                FILE *fp2;
                fp2 = fopen(filepath, "w");
                fprintf(fp2, "%lf %lf %lf\n", invalue1, invalue2, invalue3);
                fflush(fp2);
                fclose(fp2);
                write = 1;
                }           
            }
        }

    exit(0);
}

net 1p pyvcp.spinbox.0.param_pin <= paramsaver.outvalue1
net 2p pyvcp.spinbox0 => paramsaver.invalue1
net 3p pyvcp.spinbox.1.param_pin <= paramsaver.outvalue2
net 4p pyvcp.spinbox1 => paramsaver.invalue2
net 5p pyvcp.spinbox.2.param_pin <= paramsaver.outvalue3
net 6p pyvcp.spinbox2 => paramsaver.invalue3

net 7p pyvcp.load => paramsaver.readtrigger
net 8p pyvcp.write => paramsaver.writetrigger