use Fcntl; # need constants O_CREAT | O_EXCL | O_RDWR

sub get_tempfile {
    my ( $dir, $prefix, $max_tries ) = @_;
    $dir       ||= '/tmp';
    $prefix    ||= 'temp';
    $max_tries ||= 10;
    my @CHARS = ( 'A' .. 'Z', 'a' .. 'z', 0 .. 9, '_' );
    ui_system_error( "$dir is not a directory" ) unless -d $dir;
    ui_system_error( "$dir is not writable" )    unless -w $dir;
    $dir =~ s!/$!!;
    my $fh;
    for ( 0 .. $max_tries ) {
        my $name = sprintf "$prefix-%d-", time();
        $name .= $CHARS[ int( rand( $#CHARS ) ) ] for 1..10;
        my $path = "$dir/$name";
      return ($fh, $name) if sysopen($fh, $path, O_CREAT | O_EXCL | O_RDWR, 0600);
    }
    ui_system_error( "Could not create unique filename after $max_tries" );
}