[PATCH nft 2/2] src: expose nft_ctx_clear_vars as API

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

This function might be useful to recycle the existing nft_ctx to use it
with different external variables definition.

Moreover, reset ctx->num_vars to zero.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/nftables/libnftables.h | 1 +
 src/libnftables.c              | 4 +++-
 src/libnftables.map            | 1 +
 3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/nftables/libnftables.h b/include/nftables/libnftables.h
index aaf7388e6db2..8e7151a324b0 100644
--- a/include/nftables/libnftables.h
+++ b/include/nftables/libnftables.h
@@ -79,6 +79,7 @@ int nft_ctx_add_include_path(struct nft_ctx *ctx, const char *path);
 void nft_ctx_clear_include_paths(struct nft_ctx *ctx);
 
 int nft_ctx_add_var(struct nft_ctx *ctx, const char *var);
+void nft_ctx_clear_vars(struct nft_ctx *ctx);
 
 int nft_run_cmd_from_buffer(struct nft_ctx *nft, const char *buf);
 int nft_run_cmd_from_filename(struct nft_ctx *nft, const char *filename);
diff --git a/src/libnftables.c b/src/libnftables.c
index de6dc7cdae6c..aa6493aae119 100644
--- a/src/libnftables.c
+++ b/src/libnftables.c
@@ -145,7 +145,8 @@ int nft_ctx_add_var(struct nft_ctx *ctx, const char *var)
 	return 0;
 }
 
-static void nft_ctx_clear_vars(struct nft_ctx *ctx)
+EXPORT_SYMBOL(nft_ctx_clear_vars);
+void nft_ctx_clear_vars(struct nft_ctx *ctx)
 {
 	unsigned int i;
 
@@ -153,6 +154,7 @@ static void nft_ctx_clear_vars(struct nft_ctx *ctx)
 		xfree(ctx->vars[i].key);
 		xfree(ctx->vars[i].value);
 	}
+	ctx->num_vars = 0;
 	xfree(ctx->vars);
 }
 
diff --git a/src/libnftables.map b/src/libnftables.map
index 46d64a38e6e0..d3a795ce8567 100644
--- a/src/libnftables.map
+++ b/src/libnftables.map
@@ -26,4 +26,5 @@ local: *;
 
 LIBNFTABLES_2 {
   nft_ctx_add_var;
+  nft_ctx_clear_vars;
 } LIBNFTABLES_1;
-- 
2.20.1