X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FListener.pm;h=eb7dd8d46cc684fefb5dfa6c221557173c8a0ad2;hb=95bdac7f09c69036efed537a4d03d5bdd2ae4eb6;hp=f6a5da694041bfb89656eb43b3ecafc468c234ec;hpb=9bd675d33ad1e49bd2ebe12a1d216216e61380de;p=public-inbox.git

diff --git a/lib/PublicInbox/Listener.pm b/lib/PublicInbox/Listener.pm
index f6a5da69..eb7dd8d4 100644
--- a/lib/PublicInbox/Listener.pm
+++ b/lib/PublicInbox/Listener.pm
@@ -1,4 +1,4 @@
-# Copyright (C) 2015-2019 all contributors <meta@public-inbox.org>
+# Copyright (C) 2015-2020 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
@@ -8,8 +8,15 @@ use warnings;
 use base '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) = @_;
@@ -33,8 +40,21 @@ sub event_step {
 	# 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";
 	}
 }