view http_resolver_cleanup.t @ 1752:ba6e24e38f03

Tests: improved stop_daemons() to send signal again. As was observed, it's possible that a signal to complete a uwsgi daemon can be ignored while it is starting up, which results in tests hang due to eternal waiting on child processes termination. Notably, it is seen when running tests with a high number of prove jobs on a low-profile VM against nginx with broken modules and/or configuration. To reproduce: $ TEST_NGINX_GLOBALS=ERROR prove -j16 uwsgi*.t Inspecting uwsgi under ktrace on FreeBSD confirms that a SIGTERM signal is ignored at the very beginning of uwsgi startup. It is then replaced with a default action after listen(), thus waiting until uwsgi is ready to accept new TCP connections doesn't completely solve the hang window. The fix is to retry sending a signal some time after waitpid(WNOHANG) continuously demonstrated no progress with reaping a signaled process. It is modelled after f13ead27f89c that improved stop() for nginx.
author Sergey Kandaurov <pluknet@nginx.com>
date Wed, 29 Dec 2021 22:29:23 +0300
parents 766bcbb632ee
children
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#!/usr/bin/perl

# (C) Sergey Kandaurov
# (C) Nginx, Inc.

# Tests for http resolver, worker process termination.

###############################################################################

use warnings;
use strict;

use Test::More;

BEGIN { use FindBin; chdir($FindBin::Bin); }

use lib 'lib';
use Test::Nginx;

###############################################################################

select STDERR; $| = 1;
select STDOUT; $| = 1;

my $t = Test::Nginx->new()->has(qw/http proxy/);

plan(skip_all => 'win32') if $^O eq 'MSWin32';

$t->write_file_expand('nginx.conf', <<'EOF')->plan(1);

%%TEST_GLOBALS%%

daemon off;

events {
}

http {
    %%TEST_GLOBALS_HTTP%%

    server {
        listen       127.0.0.1:8080;
        server_name  localhost;

        location / {
            resolver 127.0.0.1:%%PORT_8981_UDP%%;
            proxy_pass http://example.net/$args;
        }

        location /pid {
            add_header X-Pid $pid always;
        }
    }
}

EOF

$t->run_daemon(\&dns_daemon, $t);
$t->run()->waitforfile($t->testdir . '/' . port(8981));

###############################################################################

# truncated UDP response, no response over TCP

my $s = http_get('/', start => 1);

pass('request');

sleep 1;

# retrasmission timer wasn't removed during resolver cleanup,
# while the event memory was freed, resulting in use-after-free
# when later removing timer in TCP connection

http_get('/pid') =~ qr/X-Pid: (\d+)/;
kill 'TERM', $1;

###############################################################################

sub dns_daemon {
	my ($t) = @_;
	my ($data);

	my $socket = IO::Socket::INET->new(
		LocalAddr => '127.0.0.1',
		LocalPort => port(8981),
		Proto => 'udp',
	)
		or die "Can't create UDP socket: $!\n";

	# signal we are ready

	open my $fh, '>', $t->testdir() . '/' . port(8981);
	close $fh;

	while (1) {
		$socket->recv($data, 65536);
		# truncation bit set
		$data |= pack("n2", 0, 0x8380);
		$socket->send($data);
	}
}

###############################################################################