table: Do not print unset values in json file

It changes the parse and snprintf functions to omit unset values.

Signed-off-by: Ana Rey <anarey@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/src/table.c b/src/table.c
index 78742455531f40cb81affd296c86ecd89efb9288..abbaa522abfc363885ad63f03d1f5d0890817b19 100644 (file)
--- a/src/table.c
+++ b/src/table.c
@@ -319,20 +319,15 @@ int nft_jansson_parse_table(struct nft_table *t, json_t *tree,
                return -1;
 
        str = nft_jansson_parse_str(root, "name", err);
-       if (str == NULL)
-               return -1;
-
-       nft_table_attr_set_str(t, NFT_TABLE_ATTR_NAME, str);
-
-       if (nft_jansson_parse_family(root, &family, err) != 0)
-               return -1;
-
-       nft_table_attr_set_u32(t, NFT_TABLE_ATTR_FAMILY, family);
+       if (str != NULL)
+               nft_table_attr_set_str(t, NFT_TABLE_ATTR_NAME, str);
 
-       if (nft_jansson_parse_val(root, "flags", NFT_TYPE_U32, &flags, err) < 0)
-               return -1;
+       if (nft_jansson_parse_family(root, &family, err) == 0)
+               nft_table_attr_set_u32(t, NFT_TABLE_ATTR_FAMILY, family);
 
-       nft_table_attr_set_u32(t, NFT_TABLE_ATTR_FLAGS, flags);
+       if (nft_jansson_parse_val(root, "flags", NFT_TYPE_U32, &flags,
+                                 err) == 0)
+               nft_table_attr_set_u32(t, NFT_TABLE_ATTR_FLAGS, flags);
 
        if (nft_jansson_parse_val(root, "use", NFT_TYPE_U32, &use, err) == 0)
                nft_table_attr_set_u32(t, NFT_TABLE_ATTR_USE, use);
@@ -407,16 +402,41 @@ EXPORT_SYMBOL(nft_table_parse_file);
 
 static int nft_table_snprintf_json(char *buf, size_t size, struct nft_table *t)
 {
-       return snprintf(buf, size,
-                       "{\"table\":{"
-                       "\"name\":\"%s\","
-                       "\"family\":\"%s\","
-                       "\"flags\":%d,"
-                       "\"use\":%d"
-                       "}"
-                       "}" ,
-                       t->name, nft_family2str(t->family),
-                       t->table_flags, t->use);
+       int ret, len = size, offset = 0;
+
+       ret = snprintf(buf, size, "{\"table\":{");
+       SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       ret = 0;
+
+       if (t->flags & (1 << NFT_TABLE_ATTR_NAME)) {
+               ret = snprintf(buf + offset, size, "\"name\":\"%s\",", t->name);
+               SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       }
+       if (t->flags & (1 << NFT_TABLE_ATTR_FAMILY)) {
+               ret = snprintf(buf + offset, size, "\"family\":\"%s\",",
+                              nft_family2str(t->family));
+               SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       }
+       if (t->flags & (1 << NFT_TABLE_ATTR_FLAGS)) {
+               ret = snprintf(buf + offset, size, "\"flags\":%u,",
+                              t->table_flags);
+               SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       }
+       if (t->flags & (1 << NFT_TABLE_ATTR_USE)) {
+               ret = snprintf(buf + offset, size, "\"use\":%u,", t->use);
+               SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       }
+
+       /* If  some values is set, ret is not 0. So, It's needed to remove the
+        * last comma characther
+        */
+       if (ret > 0)
+               offset--;
+
+       ret = snprintf(buf + offset, size, "}}");
+       SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+       return offset;
 }
 
 static int nft_table_snprintf_xml(char *buf, size_t size, struct nft_table *t)