Re: [PATCH nft v4] src: enable json echo output when reading native syntax

["Jose M. Guisado" <guigom@riseup.net>]

On 4/8/20 14:37, Phil Sutter wrote:
> Why not just:
> 
> --- a/src/monitor.c
> +++ b/src/monitor.c
> @@ -922,8 +922,11 @@ int netlink_echo_callback(const struct nlmsghdr *nlh, void *data)
>          if (!nft_output_echo(&echo_monh.ctx->nft->output))
>                  return MNL_CB_OK;
>   
> -       if (nft_output_json(&ctx->nft->output))
> -               return json_events_cb(nlh, &echo_monh);
> +       if (nft_output_json(&ctx->nft->output)) {
> +               if (ctx->nft->json_root)
> +                       return json_events_cb(nlh, &echo_monh);
> +               echo_monh.format = NFTNL_OUTPUT_JSON;
> +       }
>   
>          return netlink_events_cb(nlh, &echo_monh);
>   }
> 
> At a first glance, this seems to work just fine.
> 
> Cheers, Phil

This does not output anything on my machine. This is because json_echo 
is not initialized before netlink_echo_callback.

The mock monitor is responsible of appending the appropriate json cmd 
object to nft->json_echo, so we need it initialized when the case is as 
we have discussed before, native input and echo+json.

In addition netlink_echo_callback is called each time we receive 
something from the mnl socket. So checking if nft->json_echo is already 
initialized is necessary too, if not checked only the last response is 
shown, and for each past response that means a lost json_t reference to 
an array of cmd objs for that given response.

Regards.