[pve-devel] [PATCH common] tools: df: handle a failing df

[Thomas Lamprecht]

On 09/11/2017 09:23 AM, Wolfgang Bumiller wrote:
> This function assumed df() will work or hang, but it can
> also actually fail and return undef which results in
> warnings - let's silence those.

Easily reproducible with a non existing path or an unsupported
one, e.g.: /proc

> ---
>   src/PVE/Tools.pm | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/src/PVE/Tools.pm b/src/PVE/Tools.pm
> index 9ddcfda..7285c59 100644
> --- a/src/PVE/Tools.pm
> +++ b/src/PVE/Tools.pm
> @@ -985,7 +985,8 @@ sub df {
>   	$pipe->writer();
>   	eval {
>   	    my $df = Filesys::Df::df($path, 1);
> -	    print {$pipe} "$df->{blocks}\n$df->{used}\n$df->{bavail}\n";
> +	    print {$pipe} "$df->{blocks}\n$df->{used}\n$df->{bavail}\n"
> +		if defined($df);
>   	    $pipe->close();
>   	};
>   	if (my $err = $@) {
> @@ -998,9 +999,9 @@ sub df {
>       $pipe->reader();
>   
>       my $readvalues = sub {
> -	$res->{total} = int((<$pipe> =~ /^(\d*)$/)[0]);
> -	$res->{used}  = int((<$pipe> =~ /^(\d*)$/)[0]);
> -	$res->{avail} = int((<$pipe> =~ /^(\d*)$/)[0]);
> +	$res->{total} = int(((<$pipe> // 0) =~ /^(\d*)$/)[0]);
> +	$res->{used}  = int(((<$pipe> // 0) =~ /^(\d*)$/)[0]);
> +	$res->{avail} = int(((<$pipe> // 0) =~ /^(\d*)$/)[0]);
>       };
>       eval {
>   	run_with_timeout($timeout, $readvalues);
> 

looks good to me.