From 040089639f563d36b377a53ef812bc171ebcb7c2 Mon Sep 17 00:00:00 2001
From: Cloud Wu <cloudwu@gmail.com>
Date: Fri, 17 Jun 2016 12:17:53 +0800
Subject: [PATCH] memory leak bugfix in multicast, See issue #519

---
 lualib-src/lua-multicast.c | 17 +++--------------
 service/multicastd.lua     |  6 +++---
 2 files changed, 6 insertions(+), 17 deletions(-)

diff --git a/lualib-src/lua-multicast.c b/lualib-src/lua-multicast.c
index cff8d434..841267a9 100644
--- a/lualib-src/lua-multicast.c
+++ b/lualib-src/lua-multicast.c
@@ -60,18 +60,6 @@ mc_packremote(lua_State *L) {
 	return pack(L, msg, size);
 }
 
-static int
-mc_packstring(lua_State *L) {
-	size_t size;
-	const char * msg = luaL_checklstring(L, 1, &size);
-	if (size != (uint32_t)size) {
-		return luaL_error(L, "string is too long");
-	}
-	void * data = skynet_malloc(size);
-	memcpy(data, msg, size);
-	return pack(L, data, size);
-}
-
 /*
 	lightuserdata struct mc_package **
 	integer size (must be sizeof(struct mc_package *)
@@ -82,7 +70,7 @@ static int
 mc_unpacklocal(lua_State *L) {
 	struct mc_package ** pack = lua_touserdata(L,1);
 	int sz = luaL_checkinteger(L,2);
-	if (sz != sizeof(*pack)) {
+	if (sz != sizeof(pack)) {
 		return luaL_error(L, "Invalid multicast package size %d", sz);
 	}
 	lua_pushlightuserdata(L, *pack);
@@ -108,6 +96,8 @@ mc_bindrefer(lua_State *L) {
 
 	lua_pushlightuserdata(L, *pack);
 
+	skynet_free(pack);
+
 	return 1;
 }
 
@@ -161,7 +151,6 @@ luaopen_multicast_core(lua_State *L) {
 		{ "bind", mc_bindrefer },
 		{ "close", mc_closelocal },
 		{ "remote", mc_remote },
-		{ "packstring", mc_packstring },
 		{ "packremote", mc_packremote },
 		{ "nextid", mc_nextid },
 		{ NULL, NULL },
diff --git a/service/multicastd.lua b/service/multicastd.lua
index 3010e2c9..7f8506af 100644
--- a/service/multicastd.lua
+++ b/service/multicastd.lua
@@ -78,13 +78,13 @@ local function publish(c , source, pack, size)
 
 	local group = channel[c]
 	if group == nil or next(group) == nil then
-		-- dead channel, delete the pack. mc.bind returns the pointer in pack
+		-- dead channel, delete the pack. mc.bind returns the pointer in pack and free the pack (struct mc_package **)
 		local pack = mc.bind(pack, 1)
 		mc.close(pack)
 		return
 	end
-	mc.bind(pack, channel_n[c])
-	local msg = skynet.tostring(pack, size)
+	local msg = skynet.tostring(pack, size)	-- copy (pack,size) to a string
+	mc.bind(pack, channel_n[c])	-- mc.bind will free the pack(struct mc_package **)
 	for k in pairs(group) do
 		-- the msg is a pointer to the real message, publish pointer in local is ok.
 		skynet.redirect(k, source, "multicast", c , msg)