remote.c

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <complex.h>
#include <math.h>
#include <fcntl.h>
#include <complex.h>
#include <fftw3.h>
#include "sdr.h"
#include "sdr_ui.h"

static int welcome_socket = -1, data_socket = -1;
#define MAX_DATA 1000
static char incoming_data[MAX_DATA];
static int incoming_ptr;

#define MAX_LINE 30

void remote_start(){
  char buffer[MAX_DATA];
  struct sockaddr_in serverAddr;
  struct sockaddr_storage serverStorage;
  socklen_t addr_size;

  welcome_socket = socket(PF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
  
  serverAddr.sin_family = AF_INET;
  serverAddr.sin_port = htons(8081);
  serverAddr.sin_addr.s_addr = INADDR_ANY;
  memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);  

  /*---- Bind the address struct to the socket ----*/
  bind(welcome_socket, (struct sockaddr *) &serverAddr, sizeof(serverAddr));

  /*---- Listen on the socket, with 5 max connection requests queued ----*/
  if(listen(welcome_socket,5)!=0)
    printf("telnet listen() Error\n");
  incoming_ptr = 0;
}

void remote_send(char *m){
	send(data_socket, m, strlen(m), 0);
}

// from https://andreasen.org/letters/vt100.txt

void remote_init(){

	remote_send("\033[1;1H");//goto 1,1
	remote_send("\033[r"); //clear the scrollable area
	remote_send("\033[2J"); //clear the screen
	remote_send("\033[25;1r");

	remote_send(VER_STR);
	remote_send("\r\n");
}

void remote_write(char *message){
	
	if (data_socket < 0)
		return;

//	remote_send("\0337");
	int e = send(data_socket, message, strlen(message), 0);
//	remote_send("\0338");
	if (e >= 0)
		return;
	close(data_socket);
	data_socket = -1;
}

void remote_slice(){
  struct sockaddr_storage server_storage;
  socklen_t addr_size;
  int e, len;
  char buffer[1024];

  if (data_socket == -1){
    addr_size = sizeof server_storage;
    e = accept(welcome_socket, (struct sockaddr *) &server_storage, &addr_size);
    if (e == -1)
      return;
    puts("Accepted telnet connection\n");
    incoming_ptr = 0;
    data_socket = e;
    fcntl(data_socket, F_SETFL, fcntl(data_socket, F_GETFL) | O_NONBLOCK);

		// init the console
		remote_init();
  }
  else { 
    len = recv(data_socket, buffer, sizeof(buffer), 0);
    if (len > 0){
      buffer[len] = 0;
			printf("Received on remote : [%s]\n", buffer);
			//strip of the last \r or \n
			buffer[strcspn(buffer, "\r\n")] = 0;
			if (buffer[0] == '?'){
				char response[2000];
				get_field_value_by_label(buffer+1, response);
				strcat(response, "\n");
				remote_write(response);
			}	
			else if(strlen(buffer))	
				remote_execute(buffer);
    }
    else {
      //e = errno();
      if (errno == EAGAIN || errno == EWOULDBLOCK)
        return;
      //for other errors, just close the socket
			puts("telnet connection dropped. Restarting to listen ..."); 
      close(data_socket);
      data_socket = -1;      
    }
  } 
}