#!/usr/bin/env python

from __future__ import print_function

import os
import readline
import sys

if sys.version_info.major >= 3:
    raw_input = input

def waste_n_file_descriptors(n):
    open_fds = []
    for _ in range(n):
        open_fds.append(os.open('/dev/null', os.O_RDONLY))
    print('Opened file descriptors', open_fds[0], '-', open_fds[-1])

def main():
    if len(sys.argv) < 2:
        print('Supply the number of file descriptors to open on the command line.')
        print('Values >FD_SETSIZE-3 may cause a crash when the bug is present.')
        print('1024 and 32768 are some common FD_SETSIZE values in the wild.')
        sys.exit(1)

    print('Not all values will cause a crash even if they scribble on memory.')
    print('Pro tip: Compile your interpreter with ASAN for nicer diagnostics.')

    waste_n_file_descriptors(int(sys.argv[1]))

    old_stdin = sys.stdin
    try:
        sys.stdin = open('/dev/tty', 'r')
        raw_input('If this does not crash, just hit Enter.')
    finally:
        sys.stdin = old_stdin


if __name__ == '__main__':
  main()