[PATCH] selftest: net: Fix error message if empty variable

[PATCH] selftest: net: Fix error message if empty variable

[Alessandro Zanni]

Fix to avoid cases where the `res` shell variable is
empty in script comparisons.

The issue can be reproduced with the command:
make kselftest TARGETS=net

It solves the error:
./tfo_passive.sh: line 98: [: -eq: unary operator expected

Signed-off-by: Alessandro Zanni <alessandro.zanni87@gmail.com>
---
 tools/testing/selftests/net/tfo_passive.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/tfo_passive.sh b/tools/testing/selftests/net/tfo_passive.sh
index 80bf11fdc046..2655931b2396 100755
--- a/tools/testing/selftests/net/tfo_passive.sh
+++ b/tools/testing/selftests/net/tfo_passive.sh
@@ -95,7 +95,7 @@ wait
 res=$(cat $out_file)
 rm $out_file
 
-if [ $res -eq 0 ]; then
+if [ -n "$res" ] && [ $res -eq 0 ]; then
 	echo "got invalid NAPI ID from passive TFO socket"
 	cleanup_ns
 	exit 1
-- 
2.43.0

Re: [PATCH] selftest: net: Fix error message if empty variable

[Simon Horman]

On Thu, Sep 25, 2025 at 01:04:07AM +0200, Alessandro Zanni wrote:
> Fix to avoid cases where the `res` shell variable is
> empty in script comparisons.
> 
> The issue can be reproduced with the command:
> make kselftest TARGETS=net
> 
> It solves the error:
> ./tfo_passive.sh: line 98: [: -eq: unary operator expected
> 
> Signed-off-by: Alessandro Zanni <alessandro.zanni87@gmail.com>
> ---
>  tools/testing/selftests/net/tfo_passive.sh | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/net/tfo_passive.sh b/tools/testing/selftests/net/tfo_passive.sh
> index 80bf11fdc046..2655931b2396 100755
> --- a/tools/testing/selftests/net/tfo_passive.sh
> +++ b/tools/testing/selftests/net/tfo_passive.sh
> @@ -95,7 +95,7 @@ wait
>  res=$(cat $out_file)
>  rm $out_file
>  
> -if [ $res -eq 0 ]; then
> +if [ -n "$res" ] && [ $res -eq 0 ]; then
>  	echo "got invalid NAPI ID from passive TFO socket"
>  	cleanup_ns
>  	exit 1

Hi Alessandro,

I'm not sure what $res can be in practice.
But as it is the contents of $out_file (or more specifically,
the stdout of running cat $outfile), in theory it could be anything.

So while your patch addresses one error case.
I think there are others.

f.e. if res is not empty but not numeric, then we may see

bash: [: b: integer expression expected

Or if res contains a newline, then we may see

bash: [: too many arguments


So I wonder if it is better to treat $res as a string,
and quote it to avoid unexpected side effects.

[ "$res" = "0" ]

Re: [PATCH] selftest: net: Fix error message if empty variable

[Alessandro Zanni]

On Thu, Sep 25, 2025 at 11:49:30AM +0100, Simon Horman wrote:
> On Thu, Sep 25, 2025 at 01:04:07AM +0200, Alessandro Zanni wrote:
> > Fix to avoid cases where the `res` shell variable is
> > empty in script comparisons.
> > 
> > The issue can be reproduced with the command:
> > make kselftest TARGETS=net
> > 
> > It solves the error:
> > ./tfo_passive.sh: line 98: [: -eq: unary operator expected
> > 
> > Signed-off-by: Alessandro Zanni <alessandro.zanni87@gmail.com>
> > ---
> >  tools/testing/selftests/net/tfo_passive.sh | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/tools/testing/selftests/net/tfo_passive.sh b/tools/testing/selftests/net/tfo_passive.sh
> > index 80bf11fdc046..2655931b2396 100755
> > --- a/tools/testing/selftests/net/tfo_passive.sh
> > +++ b/tools/testing/selftests/net/tfo_passive.sh
> > @@ -95,7 +95,7 @@ wait
> >  res=$(cat $out_file)
> >  rm $out_file
> >  
> > -if [ $res -eq 0 ]; then
> > +if [ -n "$res" ] && [ $res -eq 0 ]; then
> >  	echo "got invalid NAPI ID from passive TFO socket"
> >  	cleanup_ns
> >  	exit 1
> 
> Hi Alessandro,
> 
> I'm not sure what $res can be in practice.
> But as it is the contents of $out_file (or more specifically,
> the stdout of running cat $outfile), in theory it could be anything.
> 
> So while your patch addresses one error case.
> I think there are others.
> 
> f.e. if res is not empty but not numeric, then we may see
> 
> bash: [: b: integer expression expected
> 
> Or if res contains a newline, then we may see
> 
> bash: [: too many arguments
> 
> 
> So I wonder if it is better to treat $res as a string,
> and quote it to avoid unexpected side effects.
> 
> [ "$res" = "0" ]

I'm not sure about the possible values in $res neither.
I assumed it was numeric because of the "-eq" operator but,
if it can be any value, a string comparison would be better.

I'm going to edit it.

Thanks,
Alessandro