my $pipe;
eval {
	local $SIG{ALRM} = sub { die "alarm\n" };
	alarm(5);
	open( $pipe, "<", $pipe_path )
		or die "pipe open failed: $!";
	alarm(0);
};
if ($@) {
	die unless ($@ eq "alarm\n"); # non-alarm failure.
	die "timeout on pipe open";
}