#!/usr/bin/python3 # Copyright (C) Internet Systems Consortium, Inc. ("ISC") # # SPDX-License-Identifier: MPL-2.0 # # This Source Code Form is subject to the terms of the Mozilla Public # License, v. 2.0. If a copy of the MPL was not distributed with this # file, you can obtain one at https://mozilla.org/MPL/2.0/. # # See the COPYRIGHT file distributed with this work for additional # information regarding copyright ownership. from concurrent.futures import ThreadPoolExecutor, as_completed import os import random import signal import subprocess from string import ascii_lowercase as letters import time import pytest pytest.importorskip("dns", minversion="2.0.0") import dns.exception import dns.resolver def do_work(named_proc, resolver, rndc_cmd, kill_method, n_workers, n_queries): """Creates a number of A queries to run in parallel in order simulate a slightly more realistic test scenario. The main idea of this function is to create and send a bunch of A queries to a target named instance and during this process a request for shutting down named will be issued. In the process of shutting down named, a couple control connections are created (by launching rndc) to ensure that the crash was fixed. if kill_method=="rndc" named will be asked to shutdown by means of rndc stop. if kill_method=="sigterm" named will be killed by SIGTERM on POSIX systems or by TerminateProcess() on Windows systems. :param named_proc: named process instance :type named_proc: subprocess.Popen :param resolver: target resolver :type resolver: dns.resolver.Resolver :param rndc_cmd: rndc command with default arguments :type rndc_cmd: list of strings, e.g. ["rndc", "-p", "23750"] :kill_method: "rndc" or "sigterm" :type kill_method: str :param n_workers: Number of worker threads to create :type n_workers: int :param n_queries: Total number of queries to send :type n_queries: int """ # pylint: disable-msg=too-many-arguments # pylint: disable-msg=too-many-locals # helper function, args must be a list or tuple with arguments to rndc. def launch_rndc(args): return subprocess.call(rndc_cmd + args, timeout=10) # We're going to execute queries in parallel by means of a thread pool. # dnspython functions block, so we need to circunvent that. with ThreadPoolExecutor(n_workers + 1) as executor: # Helper dict, where keys=Future objects and values are tags used # to process results later. futures = {} # 50% of work will be A queries. # 1 work will be rndc stop. # Remaining work will be rndc status (so we test parallel control # connections that were crashing named). shutdown = True for i in range(n_queries): if i < (n_queries // 2): # Half work will be standard A queries. # Among those we split 50% queries relname='www', # 50% queries relname=random characters if random.randrange(2) == 1: tag = "good" relname = "www" else: tag = "bad" length = random.randint(4, 10) relname = "".join( letters[random.randrange(len(letters))] for i in range(length) ) qname = relname + ".test" futures[executor.submit(resolver.resolve, qname, "A")] = tag elif shutdown: # We attempt to stop named in the middle shutdown = False if kill_method == "rndc": futures[executor.submit(launch_rndc, ["stop"])] = "stop" else: futures[executor.submit(named_proc.terminate)] = "kill" else: # We attempt to send couple rndc commands while named is # being shutdown futures[executor.submit(launch_rndc, ["status"])] = "status" ret_code = -1 for future in as_completed(futures): try: result = future.result() # If tag is "stop", result is an instance of # subprocess.CompletedProcess, then we check returncode # attribute to know if rncd stop command finished successfully. # # if tag is "kill" then the main function will check if # named process exited gracefully after SIGTERM signal. if futures[future] == "stop": ret_code = result except ( dns.resolver.NXDOMAIN, dns.resolver.NoNameservers, dns.exception.Timeout, ): pass if kill_method == "rndc": assert ret_code == 0 def wait_for_named_loaded(resolver, retries=10): for _ in range(retries): try: resolver.resolve("version.bind", "TXT", "CH") return True except (dns.resolver.NoNameservers, dns.exception.Timeout): time.sleep(1) return False def wait_for_proc_termination(proc, max_timeout=10): for _ in range(max_timeout): if proc.poll() is not None: return True time.sleep(1) proc.send_signal(signal.SIGABRT) for _ in range(max_timeout): if proc.poll() is not None: return True time.sleep(1) return False # We test named shutting down using two methods: # Method 1: using rndc ctop # Method 2: killing with SIGTERM # In both methods named should exit gracefully. @pytest.mark.parametrize("kill_method", ["rndc", "sigterm"]) def test_named_shutdown(named_port, control_port, kill_method): # pylint: disable-msg=too-many-locals cfg_dir = os.path.join(os.getcwd(), "resolver") assert os.path.isdir(cfg_dir) cfg_file = os.path.join(cfg_dir, "named.conf") assert os.path.isfile(cfg_file) named = os.getenv("NAMED") assert named is not None rndc = os.getenv("RNDC") assert rndc is not None # rndc configuration resides in ../_common/rndc.conf rndc_cfg = os.path.join("..", "_common", "rndc.conf") assert os.path.isfile(rndc_cfg) # rndc command with default arguments. rndc_cmd = [rndc, "-c", rndc_cfg, "-p", str(control_port), "-s", "10.53.0.3"] # We create a resolver instance that will be used to send queries. resolver = dns.resolver.Resolver() resolver.nameservers = ["10.53.0.3"] resolver.port = named_port named_cmdline = [named, "-c", cfg_file, "-f"] with subprocess.Popen(named_cmdline, cwd=cfg_dir) as named_proc: try: assert named_proc.poll() is None, "named isn't running" assert wait_for_named_loaded(resolver) do_work( named_proc, resolver, rndc_cmd, kill_method, n_workers=12, n_queries=16, ) assert wait_for_proc_termination(named_proc) assert named_proc.returncode == 0, "named crashed" finally: # Ensure named is terminated in case of an exception named_proc.kill()