Re: [nft PATCH v2 1/4] libnftables: Move library stuff out of main.c

[Pablo Neira Ayuso <pablo@netfilter.org>]

Hi Phil,

Just follow up comments, several things that I think we can polish,
see below.

On Mon, Oct 23, 2017 at 05:33:16PM +0200, Phil Sutter wrote:
[...]
> diff --git a/include/nftables/nftables.h b/include/nftables/nftables.h
> new file mode 100644
> index 0000000000000..44d3e95d399e6
> --- /dev/null
> +++ b/include/nftables/nftables.h
> @@ -0,0 +1,58 @@
> +/*
> + * Copyright (c) 2017 Eric Leblond <eric@regit.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +#ifndef LIB_NFTABLES_H
> +#define LIB_NFTABLES_H
> +
> +#define _GNU_SOURCE
> +#include <stdint.h>
> +#include <stdio.h>
> +#include <stdbool.h>
> +
> +struct nft_ctx;
> +
> +enum debug_level {
> +	DEBUG_SCANNER		= 0x1,
> +	DEBUG_PARSER		= 0x2,
> +	DEBUG_EVALUATION	= 0x4,
> +	DEBUG_NETLINK		= 0x8,
> +	DEBUG_MNL		= 0x10,
> +	DEBUG_PROTO_CTX		= 0x20,
> +	DEBUG_SEGTREE		= 0x40,
> +};
> +
> +enum numeric_level {
> +	NUMERIC_NONE,
> +	NUMERIC_ADDR,
> +	NUMERIC_PORT,
> +	NUMERIC_ALL,
> +};

Just pushed out a patch to prepend NFT_ prefix.

> +/**
> + * Possible flags to pass to nft_ctx_new()
> + */
> +#define NFT_CTX_DEFAULT		0
> +
> +/**
> + * Exit codes returned by nft_run_cmd_from_*()
> + */
> +enum nftables_exit_codes {
> +	NFT_EXIT_SUCCESS	= 0,
> +	NFT_EXIT_FAILURE	= 1,
> +	NFT_EXIT_NOMEM		= 2,
> +	NFT_EXIT_NONL		= 3,
> +};

I think library is currently aborting in case of no-netlink and
no-memory, so these two error codes are not useful.

We would need to change codebase to propagate errors up to the
callers.

Regarding error code, I would go for -1 in case of error instead and 0
in case of success. If failure happens, then set errno with reason, so
we can get rid of these exit codes in a follow up patch?