RE: [PATCH] selftests: net: tcp_fastopen_backup_key.sh: fix shellcheck issue

[Tim.Bird]

> -----Original Message-----
> From: Anders Roxell
> 
> When running tcp_fastopen_backup_key.sh the following issue was seen in
> a busybox environment.
> ./tcp_fastopen_backup_key.sh: line 33: [: -ne: unary operator expected
> 
> Shellcheck showed the following issue.
> $ shellcheck tools/testing/selftests/net/tcp_fastopen_backup_key.sh
> 
> In tools/testing/selftests/net/tcp_fastopen_backup_key.sh line 33:
>         if [ $val -ne 0 ]; then
>              ^-- SC2086: Double quote to prevent globbing and word splitting.
> 
> Rework to add double quotes around the variable 'val' that shellcheck
> recommends.
> 
> Signed-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
> ---
>  tools/testing/selftests/net/tcp_fastopen_backup_key.sh | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
> b/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
> index 41476399e184..ba5ec3eb314e 100755
> --- a/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
> +++ b/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
> @@ -30,7 +30,7 @@ do_test() {
>  	ip netns exec "${NETNS}" ./tcp_fastopen_backup_key "$1"
>  	val=$(ip netns exec "${NETNS}" nstat -az | \
>  		grep TcpExtTCPFastOpenPassiveFail | awk '{print $2}')
> -	if [ $val -ne 0 ]; then
> +	if [ "$val" -ne 0 ]; then

Did you test this in the failing environment?

With a busybox shell, I get:
 $ [ "" -ne 0 ]
sh: bad number

You might need to explicitly check for empty string here, or switch to a string comparison instead:
if [ "$val" != 0 ]; then

   -- Tim

>  		echo "FAIL: TcpExtTCPFastOpenPassiveFail non-zero"
>  		return 1
>  	fi
> --
> 2.20.1