#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/syscall.h>
#include <unistd.h>

#define NUM_THREADS 1

static pthread_attr_t attr;

void *thr(void *arg) {
  if (pthread_create(&(pthread_t){0}, &attr, thr, 0))
    abort();
  return 0;
}

int main(void) {
  pthread_attr_init(&attr);
  pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
  for (int i = 0; i < NUM_THREADS; i++)
    if (pthread_create(&(pthread_t){0}, &attr, thr, 0))
      abort();

  int euid = geteuid();
  for (int it = 0;; it++) {
    printf("%d\n", it);
    if (seteuid(euid)) {
      perror("seteuid");
      abort();
    }
  }
}