#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <setjmp.h>

const int SIGNAL_TYPE = SIGSEGV;

// Global flag and jump buffer for recovery
static jmp_buf env_buffer;
static volatile int handled = 0;

void handler(int signal_num) {
  handled += 1;
  longjmp(env_buffer, 1);
}

int trigger() {
  if(setjmp(env_buffer)) {
    return 1;
  }
  //volatile char _ = *((char*)0);
  raise(SIGNAL_TYPE);
  return 0;
}

int printSigMasks() {
  sigset_t set;
  // Get the current signal mask
  if (sigprocmask(SIG_BLOCK, NULL, &set) == -1) {
      perror("sigprocmask");
      return 1;
  }
  // Print blocked signal masks
  int blocked = 0;
  for (int i = 1; i < NSIG; ++i) {
      if (sigismember(&set, i)) {
          blocked += 1;
          printf("Signal %d is blocked\n", i);
      }
  }
  if(!blocked) {
    printf("No blocked signals\n");
  }
  return 0;
}

int main(int argc, char *argv[]) {
  printf("NSIG = %i\n", NSIG);

  void* sig_res = signal(SIGNAL_TYPE, handler);
  if(sig_res == SIG_ERR) {
    printf("Error setting signal handler\n");
    exit(EXIT_FAILURE);
  }
  
  int result = 0;
  printSigMasks();
  result = trigger();
  printf("Raised = %i\tHandled = %i\n", result, handled);
  printSigMasks();
  result = trigger();
  printf("Raised = %i\tHandled = %i\n", result, handled);
  printSigMasks();

  return EXIT_SUCCESS;
}