Re: [PATCH bpf v1 2/3] selftests/bpf: Print a message when tester could not run a program

[Jakub Kicinski <jakub.kicinski@netronome.com>]

On Wed, 15 May 2019 15:47:27 +0200, Krzesimir Nowak wrote:
> This prints a message when the error is about program type being not
> supported by the test runner or because of permissions problem. This
> is to see if the program we expected to run was actually executed.
> 
> The messages are open-coded because strerror(ENOTSUPP) returns
> "Unknown error 524".
> 
> Signed-off-by: Krzesimir Nowak <krzesimir@kinvolk.io>
> ---
>  tools/testing/selftests/bpf/test_verifier.c | 17 +++++++++++++----
>  1 file changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
> index ccd896b98cac..bf0da03f593b 100644
> --- a/tools/testing/selftests/bpf/test_verifier.c
> +++ b/tools/testing/selftests/bpf/test_verifier.c
> @@ -825,11 +825,20 @@ static int do_prog_test_run(int fd_prog, bool unpriv, uint32_t expected_val,
>  				tmp, &size_tmp, &retval, NULL);
>  	if (unpriv)
>  		set_admin(false);
> -	if (err && errno != 524/*ENOTSUPP*/ && errno != EPERM) {
> -		printf("Unexpected bpf_prog_test_run error ");
> -		return err;
> +	if (err) {
> +		switch (errno) {
> +		case 524/*ENOTSUPP*/:
> +			printf("Did not run the program (not supported) ");
> +			return 0;
> +		case EPERM:
> +			printf("Did not run the program (no permission) ");
> +			return 0;

Perhaps use strerror(errno)?

> +		default:
> +			printf("Unexpected bpf_prog_test_run error ");
> +			return err;
> +		}
>  	}
> -	if (!err && retval != expected_val &&
> +	if (retval != expected_val &&
>  	    expected_val != POINTER_VALUE) {
>  		printf("FAIL retval %d != %d ", retval, expected_val);
>  		return 1;