+sub request_umask {
+ my ($lei) = @_;
+ my $s = $lei->{sock} // return;
+ send($s, 'umask', MSG_EOR) // die "send: $!";
+ vec(my $rvec = '', fileno($s), 1) = 1;
+ select($rvec, undef, undef, 2) or die 'timeout waiting for umask';
+ recv($s, my $v, 5, 0) // die "recv: $!";
+ (my $u, $lei->{client_umask}) = unpack('AV', $v);
+ $u eq 'u' or warn "E: recv $v has no umask";
+}
+