# Copyright (C) 2020-2021 all contributors # License: AGPL-3.0+ # 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 not many other distros as of 2021. package PublicInbox::CmdIPC4; use strict; use v5.10.1; use Socket qw(SOL_SOCKET SCM_RIGHTS); BEGIN { eval { require Socket::MsgHdr; # XS no warnings 'once'; # any number of FDs per-sendmsg(2) + buffer *send_cmd4 = sub ($$$$) { # (sock, fds, buf, flags) = @_; my ($sock, $fds, undef, $flags) = @_; my $mh = Socket::MsgHdr->new(buf => $_[2]); $mh->cmsghdr(SOL_SOCKET, SCM_RIGHTS, pack('i' x scalar(@$fds), @$fds)); my $s; my $try = 0; do { $s = Socket::MsgHdr::sendmsg($sock, $mh, $flags); } while (!defined($s) && ($!{ENOBUFS} || $!{ENOMEM} || $!{ETOOMANYREFS}) && (++$try < 50) && warn "sleeping on sendmsg: $! (#$try)\n" && select(undef, undef, undef, 0.1) == 0); $s; }; *recv_cmd4 = sub ($$$) { my ($s, undef, $len) = @_; # $_[1] = destination buffer my $mh = Socket::MsgHdr->new(buflen => $len, controllen => 256); my $r = Socket::MsgHdr::recvmsg($s, $mh, 0) // return ($_[1] = undef); $_[1] = $mh->buf; return () if $r == 0; my (undef, undef, $data) = $mh->cmsghdr; defined($data) ? unpack('i' x (length($data) / 4), $data) : (); }; } } # /eval /BEGIN 1;