#include <stdlib.h>
#include <unistd.h>
#include <string.h>

char *first_message = "Hi! How much do you want me to read?\n";
char *second_message = "OK, give me the stuff!\n";
char *third_message = "OK, here's what you said:\n";
char *fourth_message = "Give me more!\n";
char *fifth_message = "OK, all done.\n";
char *fail_message = "Aborting! Error in param.\n";

void secure_function(int param) {
  char len_buf[8];
  char legit_buf[8];
  unsigned long amount;

  if (param != 0xDEADBEEF) {
    write(1, fail_message, strlen(fail_message));
    return;
  }

  memset(legit_buf, 0, 8);

  write(1, first_message, strlen(first_message));
  read(0, len_buf, 7);
  len_buf[7] = 0;

  amount = strtoul(len_buf, NULL, 0);

  write(1, second_message, strlen(second_message));
  read(0, legit_buf, amount);

  write(1, third_message, strlen(third_message));
  write(1, legit_buf, amount);

  write(1, fourth_message, strlen(fourth_message));
  read(0, legit_buf, amount);

  write(1, fifth_message, strlen(fifth_message));

  return;
}

int main() {
  char blah[50000];
  secure_function(0xDEADBEEF);
}