X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FListener.pm;h=c831581076a0d582dfcd44ba0ca8c65b010dd797;hb=af0b0fb7a454470a32c452119d0392e0dedb3fe1;hp=a75a6fd9964ed1c9c2d2780b6680aa1b39ee76b2;hpb=fe86054ee1e2d93b19762a34ed1aaebe43635ff0;p=public-inbox.git

diff --git a/lib/PublicInbox/Listener.pm b/lib/PublicInbox/Listener.pm
index a75a6fd9..c8315810 100644
--- a/lib/PublicInbox/Listener.pm
+++ b/lib/PublicInbox/Listener.pm
@@ -1,31 +1,33 @@
-# Copyright (C) 2015-2018 all contributors <meta@public-inbox.org>
+# 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 'PublicInbox::DS';
+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 EPOLLET);
+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($s, IPPROTO_TCP, TCP_NODELAY, 1); # ignore errors on non-TCP
 	listen($s, 1024);
-	IO::Handle::blocking($s, 0);
-	my $self = fields::new($class);
-	$self->SUPER::new($s, 1); # calls epoll_create for the first socket
-	$self->watch_read(1);
-	$self->{post_accept} = $cb;
-	$self
+	my $self = bless { post_accept => $cb }, $class;
+	$self->SUPER::new($s, EPOLLIN|EPOLLET|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
@@ -34,7 +36,21 @@ sub event_read {
 	# 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 $@;
+		$self->requeue;
+	} elsif ($! == 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";
 	}
 }