gluon-mesh-batman-adv: respondd: determine compat version from release version

We cannot add the same file (here: /lib/gluon/mesh-batman-adv/compat) to
two, installed packages. Therefore, instead of determining the compat
version number from this file, infer it from the batman-adv release
version number instead.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>

package/gluon-mesh-batman-adv/src/respondd.c

@@ -232,25 +232,24 @@ static struct json_object * get_mesh(void) {
 	return ret;
 }
 
-static struct json_object * get_batman_adv_compat(void) {
-	FILE *f = fopen("/lib/gluon/mesh-batman-adv/compat", "r");
-	if (!f)
-		return NULL;
-
-	struct json_object *ret = NULL;
+static struct json_object * get_batman_adv_compat(const char *version) {
+	int compat = 15;
 
-	int compat;
-	if (fscanf(f, "%i", &compat) == 1)
-		ret = json_object_new_int(compat);
+	if (!version)
+		return NULL;
 
-	fclose(f);
+	if (strcmp(version, "2013.4.0") == 0)
+		compat = 14;
 
-	return ret;
+	return json_object_new_int(compat);
 }
 
 static struct json_object * respondd_provider_nodeinfo(void) {
 	struct json_object *ret = json_object_new_object();
 
+	char *version = gluonutil_read_line("/sys/module/batman_adv/version");
+	struct json_object *compat = get_batman_adv_compat(version);
+
 	struct json_object *network = json_object_new_object();
 	json_object_object_add(network, "addresses", get_addresses());
 	json_object_object_add(network, "mesh", get_mesh());
@@ -258,8 +257,8 @@ static struct json_object * respondd_provider_nodeinfo(void) {
 
 	struct json_object *software = json_object_new_object();
 	struct json_object *software_batman_adv = json_object_new_object();
-	json_object_object_add(software_batman_adv, "version", gluonutil_wrap_and_free_string(gluonutil_read_line("/sys/module/batman_adv/version")));
-	json_object_object_add(software_batman_adv, "compat", get_batman_adv_compat());
+	json_object_object_add(software_batman_adv, "version", gluonutil_wrap_and_free_string(version));
+	json_object_object_add(software_batman_adv, "compat", compat);
 	json_object_object_add(software, "batman-adv", software_batman_adv);
 	json_object_object_add(ret, "software", software);