// changed parts in common.h:
...
int mystdin[2];   // pipes to child process
int mystdout[2];

void print_unencrypted_data(char *buf, size_t len) {
  printf("from SSL to bash: %d bytes", (int)len);
  write(mystdin[1],buf,(int)len); // write to child's stdin instead of stdout
}
...
void do_stdin_read()
{
  char buf[DEFAULT_BUF_SIZE];
  //ssize_t n = read(STDIN_FILENO, buf, sizeof(buf));
  ssize_t n = read(mystdout[0], buf, sizeof(buf)); // read from child's stdout instead of stdin
  //printf("from shell: %.*s", (int)n, buf);
  if (n>0)
    send_unencrypted_bytes(buf, (size_t)n);
}
...

// changed part in main:
int main(int argc, char **argv)
{
  ...
  if (connect(sockfd, (struct sockaddr*) &addr, sizeof(addr)) < 0)
    die("connect()");

  // added code:

  pipe(mystdin);
  pipe(mystdout);

  int pid = fork();
  if (pid==(pid_t)0) // child: simple echo
  {
    close(mystdin[1]);
    close(mystdout[0]);
    char buf;
    int i;
    while(1)
    {
      read(mystdin[0],&buf,1);
      write(mystdout[1],&buf,1);
      // replace "a" by a very large output:
      if (buf=='a')
        for (i=0; i<160000; i++) // 160000 might have to be increased depending on system
          write(mystdout[1],&buf,1);
    }
    return 0;
  }

  // parent
  close(mystdin[0]);
  close(mystdout[1]);

  if (pid>(pid_t)0)
  {
    struct pollfd fdset[2];
    memset(&fdset, 0, sizeof(fdset));

    fdset[0].fd = mystdout[0]; //STDIN_FILENO; // stdout[0];
    fdset[0].events = POLLIN;
    // original code from here
  }
  return 0;
}