X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FCmdIPC4.pm;h=76938b6d36dc4c16a89ecf63be1ff487a2e6217d;hb=215e2138c99d48e2061eb98aef5a6da1bc3ff828;hp=c4fcb0d679d9256319ab6f5b45e86d72772256e4;hpb=6cc0e6870cb4950c08646769f2a7e30729b7d409;p=public-inbox.git

diff --git a/lib/PublicInbox/CmdIPC4.pm b/lib/PublicInbox/CmdIPC4.pm
index c4fcb0d6..76938b6d 100644
--- a/lib/PublicInbox/CmdIPC4.pm
+++ b/lib/PublicInbox/CmdIPC4.pm
@@ -1,9 +1,9 @@
-# Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
+# Copyright (C) all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 
 # callers should use PublicInbox::CmdIPC4->can('send_cmd4') (or recv_cmd4)
 # first choice for script/lei front-end and 2nd choice for lei backend
-# libsocket-msghdr-perl is in Debian but many other distros as of 2021.
+# libsocket-msghdr-perl is in Debian but not many other distros as of 2021.
 package PublicInbox::CmdIPC4;
 use strict;
 use v5.10.1;
@@ -12,23 +12,31 @@ BEGIN { eval {
 require Socket::MsgHdr; # XS
 no warnings 'once';
 
-# 3 FDs per-sendmsg(2) + buffer
+# any number of FDs per-sendmsg(2) + buffer
 *send_cmd4 = sub ($$$$) { # (sock, fds, buf, flags) = @_;
 	my ($sock, $fds, undef, $flags) = @_;
 	my $mh = Socket::MsgHdr->new(buf => $_[2]);
-	$mh->cmsghdr(SOL_SOCKET, SCM_RIGHTS,
-			pack('i' x scalar(@$fds), @$fds));
-	Socket::MsgHdr::sendmsg($sock, $mh, $flags) or die "sendmsg: $!";
+	$mh->cmsghdr(SOL_SOCKET, SCM_RIGHTS, pack('i' x scalar(@$fds), @$fds));
+	my $s;
+	my $try = 0;
+	do {
+		$s = Socket::MsgHdr::sendmsg($sock, $mh, $flags);
+	} while (!defined($s) &&
+			($!{ENOBUFS} || $!{ENOMEM} || $!{ETOOMANYREFS}) &&
+			(++$try < 50) &&
+			warn "sleeping on sendmsg: $! (#$try)\n" &&
+			select(undef, undef, undef, 0.1) == 0);
+	$s;
 };
 
 *recv_cmd4 = sub ($$$) {
 	my ($s, undef, $len) = @_; # $_[1] = destination buffer
 	my $mh = Socket::MsgHdr->new(buflen => $len, controllen => 256);
-	my $r = Socket::MsgHdr::recvmsg($s, $mh, 0) // die "recvmsg: $!";
+	my $r = Socket::MsgHdr::recvmsg($s, $mh, 0) // return (undef);
 	$_[1] = $mh->buf;
 	return () if $r == 0;
 	my (undef, undef, $data) = $mh->cmsghdr;
-	unpack('i' x (length($data) / 4), $data);
+	defined($data) ? unpack('i' x (length($data) / 4), $data) : ();
 };
 
 } } # /eval /BEGIN