#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>

volatile int serversock, sock;

void kill_me(int sig) 
{
  close(serversock); close(sock);
  exit(1);
}

#define PORT 12345

/** binds to port PORT and prints everything received that is not the ascii-letter a */
int main(int argc, char **argv) { 
  signal(SIGINT, kill_me); 
  serversock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);

  if (serversock == -1) { 
    perror("Error creating socket");
    exit(1);
  }
  
  int on = 1;
  if (setsockopt(serversock, SOL_SOCKET, SO_REUSEADDR, (char*)&on, sizeof(on)) == -1) {
    perror("Setsockopt");
    exit(1);
  }
    
  struct sockaddr_in server = {0};
  server.sin_family = AF_INET;
  server.sin_addr.s_addr = htonl(INADDR_ANY);
  server.sin_port = htons(PORT);

  if (bind(serversock, (struct sockaddr *) &server, sizeof(server)) == -1) {
    perror("Error binding socket");
    exit(1);
  }

  if (listen(serversock, 2) == -1) {
    perror("Listening for connection");
    exit(1);
  }
  

  while (1) {
    struct sockaddr_in client;
    int sock;
    unsigned int clientlen = sizeof(client);

    /* Wait for client connection */
    sock = accept(serversock, (struct sockaddr *) &client, &clientlen);
    if (sock == -1) {
      perror("Accepting connection");
      exit(1);
    }
    
    int n;
    do {
      sleep(1);
      char buf[20001];
      n = recv(sock, buf, 20000, 0);
      if (n == -1) {
        perror("Failed...");
        if (!(errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 
          break;
      } 
      int i;
      
      for (i = 0; i < n; ++i) {
        if (buf[i] != 'a') 
          putchar(buf[i]);
      }
    } while(n);
    close(sock);
  }
  close(serversock);
}