treewide: run update-copyrights from gnulib for 2019

[public-inbox.git] / lib / PublicInbox / Listener.pm

diff --git a/lib/PublicInbox/Listener.pm b/lib/PublicInbox/Listener.pm
index f6a5da694041bfb89656eb43b3ecafc468c234ec..eb7dd8d46cc684fefb5dfa6c221557173c8a0ad2 100644 (file)
--- 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";
        }
 }