#include <stdio.h>
#include <stdlib.h>
#include <sys/select.h>
#include <sys/wait.h>
#include <unistd.h>

int
main (int argc, char **argv)
{
  int test_case_count = argc < 2 ? 10000: atoi (argv[1]);
  int delay_in_nanoseconds = argc < 3 ? 1000 : atoi (argv[2]);
  int i;
  for (i = 0; i < test_case_count; i++)
    {
      pid_t p = vfork ();
      int ok = 0;
      int volatile child_status = 0;
      if (p < 0)
	{
	  perror ("vfork");
	  return 2;
	}
      if (p == 0)
	{
	  struct timespec timeout;
	  timeout.tv_sec = 0;
	  timeout.tv_nsec = delay_in_nanoseconds;
	  pselect (0, 0, 0, 0, &timeout, 0);
	  _exit (child_status);
	}
      if (p > 0)
	{
	  int status;
	  child_status = 1;
	  if (waitpid (p, &status, 0) == p
	      && WIFEXITED (status) && status == 0)
	    ok = 1;
	  if (!ok)
	    {
	      printf ("vfork bug detected\n");
	      return 1;
	    }
	}
    }
  return 0;
}