#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/resource.h>

int
main (void)
{
#define N1 100
  struct rlimit r;
  r.rlim_cur = N1;
  r.rlim_max = N1;
  setrlimit (RLIMIT_NOFILE, &r);
  int i;
  int fd[N1];
  for (i = 0; ; ++i)
    if ((fd[i] = open ("/dev/null", 0)) < 0)
      {
        if (i == N1 - 3)
          printf ("fine, %d file descriptors open\n", N1);
        else
          {
            puts ("*** make sure the parent doesn't open any descriptors other than 0, 1, 2");
            return 1;
          }
        break;
      }
#define N2 50
  r.rlim_cur = N2; 
  r.rlim_max = N2; 
  int e = setrlimit (RLIMIT_NOFILE, &r);
  if (e == EINVAL)
    {
      puts ("good, setrlimit sees the open descriptors");
      return 0;
    }
  getrlimit (RLIMIT_NOFILE, &r);
  if (r.rlim_cur != N2 || r.rlim_max != N2)
    {
      puts ("getrlimit returned different values");
      return 1;
    }
  close (fd[N2 - 4]);
  fd[N2 - 4] = open ("/dev/null", 0);
  if (fd[N2 - 4] != -1)
    {
      printf ("opening a new descriptor succeeded even though %d are open and the limit is %d\n",
              N1 - 1, N2);
      return 1;
    }
  return 0;
}