import os

def close_file_descriptors(fd_min=3, fd_max=-1, debug=False):
    import resource
    fd_top = resource.getrlimit(resource.RLIMIT_NOFILE)[1] - 1
    if fd_max == -1 or fd_max > fd_top:
        fd_max = fd_top
    if debug:
        print "closing fds from %s to %s" % (fd_min, fd_max)
    for fd in range(fd_min, fd_max+1):
        try:
            os.close(fd)
        except OSError:
            pass

close_file_descriptors(debug=True)