From: Luka Perkov <luka@openwrt.org>
Date: Sun, 26 Jan 2014 17:33:36 +0000 (+0000)
Subject: lua: allow methods with no arguments
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=4e82a1fabb87b5e3c948a792e16b0fac3702721b;p=oweals%2Fubus.git

lua: allow methods with no arguments

In C it is possible to have methods without arguments (UBUS_METHOD_NOARG).
Enable support for the same calls in Lua too.

This commit also fixes segfault which can be caused by passing non-table type
where table is expected. The lua_gettablelen() function is called after we have
made sure we are dealing with a table in the first place.

Signed-off-by: Luka Perkov <luka@openwrt.org>
---

diff --git a/lua/ubus.c b/lua/ubus.c
index 45ea3bb..6da935d 100644
--- a/lua/ubus.c
+++ b/lua/ubus.c
@@ -349,12 +349,11 @@ static int ubus_lua_load_methods(lua_State *L, struct ubus_method *m)
 	/* get the policy table */
 	lua_pushinteger(L, 2);
 	lua_gettable(L, -3);
-	plen = lua_gettablelen(L, -1);
 
 	/* check if the method table is valid */
 	if ((lua_type(L, -2) != LUA_TFUNCTION) ||
 			(lua_type(L, -1) != LUA_TTABLE) ||
-			lua_objlen(L, -1) || !plen) {
+			lua_objlen(L, -1)) {
 		lua_pop(L, 2);
 		return 1;
 	}
@@ -363,6 +362,17 @@ static int ubus_lua_load_methods(lua_State *L, struct ubus_method *m)
 	lua_pushvalue(L, -2);
 	lua_setfield(L, -6, lua_tostring(L, -5));
 
+	m->name = lua_tostring(L, -4);
+	m->handler = ubus_method_handler;
+
+	plen = lua_gettablelen(L, -1);
+
+	/* exit if policy table is empty */
+	if (!plen) {
+		lua_pop(L, 2);
+		return 0;
+	}
+
 	/* setup the policy pointers */
 	p = malloc(sizeof(struct blobmsg_policy) * plen);
 	memset(p, 0, sizeof(struct blobmsg_policy) * plen);
@@ -386,8 +396,6 @@ static int ubus_lua_load_methods(lua_State *L, struct ubus_method *m)
 	}
 
 	m->n_policy = pidx;
-	m->name = lua_tostring(L, -4);
-	m->handler = ubus_method_handler;
 	lua_pop(L, 2);
 
 	return 0;