Reviewed-by: Peter Müller <peter.mueller(a)ipfire.org>

> Prevents "use of uninitialized value" warnings when the
> CGI is called with broken undefined GET parameters.
> 
> Signed-off-by: Leo-Andres Hofmann <hofmann(a)leo-andres.de>
> ---
>  html/cgi-bin/getrrdimage.cgi | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/html/cgi-bin/getrrdimage.cgi b/html/cgi-bin/getrrdimage.cgi
> index 26e026bba..6ec91cc92 100644
> --- a/html/cgi-bin/getrrdimage.cgi
> +++ b/html/cgi-bin/getrrdimage.cgi
> @@ -44,9 +44,9 @@ my @supported_origins = ("entropy.cgi", "hardwaregraphs.cgi", "media.cgi",
>  my $uri = URI->new($ENV{'REQUEST_URI'});
>  my %query = $uri->query_form;
>  
> -my $origin = lc $query{'origin'}; # lower case
> -my $graph = $query{'graph'};
> -my $range = lc $query{'range'}; # lower case
> +my $origin = lc ($query{'origin'} // ''); # lower case
> +my $graph = $query{'graph'} // '';
> +my $range = lc ($query{'range'} // ''); # lower case
>  
>  # Check parameters
>  unless(($origin =~ /^\w+?\.cgi$/) && ($graph =~ /^[\w\-.,; ]+?$/) && ($range ~~ @Graphs::time_ranges)) {