-# Copyright (C) 2015 all contributors <meta@public-inbox.org>
-# License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt)
+# Copyright (C) 2015-2021 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
#
# Used by -nntpd for listen sockets
package PublicInbox::Listener;
use strict;
-use warnings;
-use base 'Danga::Socket';
+use parent 'PublicInbox::DS';
use Socket qw(SOL_SOCKET SO_KEEPALIVE IPPROTO_TCP TCP_NODELAY);
-use fields qw(post_accept);
-require IO::Handle;
+use IO::Handle;
+use PublicInbox::Syscall qw(EPOLLIN EPOLLEXCLUSIVE);
+use Errno qw(EAGAIN ECONNABORTED EPERM);
+
+# Warn on transient errors, mostly resource limitations.
+# EINTR would indicate the failure to set NonBlocking in systemd or similar
+my %ERR_WARN = map {;
+ eval("Errno::$_()") => $_
+} qw(EMFILE ENFILE ENOBUFS ENOMEM EINTR);
sub new ($$$) {
my ($class, $s, $cb) = @_;
setsockopt($s, SOL_SOCKET, SO_KEEPALIVE, 1);
- setsockopt($s, IPPROTO_TCP, TCP_NODELAY, 1);
- listen($s, 1024);
- IO::Handle::blocking($s, 0);
- my $self = fields::new($class);
- $self->SUPER::new($s); # calls epoll_create for the first socket
- $self->watch_read(1);
- $self->{post_accept} = $cb;
- $self
+ setsockopt($s, IPPROTO_TCP, TCP_NODELAY, 1); # ignore errors on non-TCP
+ listen($s, 2**31 - 1); # kernel will clamp
+ my $self = bless { post_accept => $cb }, $class;
+ $self->SUPER::new($s, EPOLLIN|EPOLLEXCLUSIVE);
}
-sub event_read {
+sub event_step {
my ($self) = @_;
- my $sock = $self->{sock};
+ my $sock = $self->{sock} or return;
+
# no loop here, we want to fairly distribute clients
# between multiple processes sharing the same socket
+ # XXX our event loop needs better granularity for
+ # a single accept() here to be, umm..., acceptable
+ # on high-traffic sites.
if (my $addr = accept(my $c, $sock)) {
IO::Handle::blocking($c, 0); # no accept4 :<
- $self->{post_accept}->($c, $addr, $sock);
+ eval { $self->{post_accept}->($c, $addr, $sock) };
+ warn "E: $@\n" if $@;
+ } elsif ($! == EAGAIN || $! == ECONNABORTED || $! == EPERM) {
+ # EAGAIN is common and likely
+ # ECONNABORTED is common with bad connections
+ # EPERM happens if firewall rules prevent a connection
+ # on Linux (and everything that emulates Linux).
+ # Firewall rules are sometimes intentional, so we don't
+ # warn on EPERM to avoid being too noisy...
+ return;
+ } elsif (my $sym = $ERR_WARN{int($!)}) {
+ warn "W: accept(): $! ($sym)\n";
+ } else {
+ warn "BUG?: accept(): $!\n";
}
}