From 62a22aa23f761a40c8b473bfdec07d01b7779846 Mon Sep 17 00:00:00 2001
From: Thierry Fournier <thierry.fournier@ozon.io>
Date: Sat, 28 Nov 2020 21:06:35 +0100
Subject: [PATCH] MINOR: lua-thread: Replace "struct hlua_function" allocation
 by dedicated function

The goal is to allow execution of one main lua state per thread.

This function will initialize the struct with other things than 0.
With this function helper, the initialization is centralized and
it prevents mistakes. This patch also keeps a reference to each
declared function in a list. It will be useful in next patches to
control consistency of declared references.
---
 include/haproxy/hlua-t.h |  1 +
 src/hlua.c               | 27 ++++++++++++++++++++++-----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/include/haproxy/hlua-t.h b/include/haproxy/hlua-t.h
index 12c3cf2fc..86a327672 100644
--- a/include/haproxy/hlua-t.h
+++ b/include/haproxy/hlua-t.h
@@ -111,6 +111,7 @@ struct hlua_init_function {
  * or actions.
  */
 struct hlua_function {
+	struct list l;
 	char *name;
 	int function_ref;
 	int nargs;
diff --git a/src/hlua.c b/src/hlua.c
index 6cb5e2c3b..3e903110f 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -124,6 +124,12 @@ THREAD_LOCAL jmp_buf safe_ljmp_env;
 static int hlua_panic_safe(lua_State *L) { return 0; }
 static int hlua_panic_ljmp(lua_State *L) { WILL_LJMP(longjmp(safe_ljmp_env, 1)); }
 
+/* This is the chained list of struct hlua_function referenced
+ * for haproxy action, sample-fetches, converters, cli and
+ * applet bindings. It is used for a post-initialisation control.
+ */
+static struct list referenced_functions = LIST_HEAD_INIT(referenced_functions);
+
 #define SET_SAFE_LJMP_L(__L, __HLUA) \
 	({ \
 		int ret; \
@@ -277,6 +283,17 @@ __LJMP static int hlua_http_get_headers(lua_State *L, struct http_msg *msg);
 			ha_alert(__fmt, ## __args); \
 	} while (0)
 
+static inline struct hlua_function *new_hlua_function()
+{
+	struct hlua_function *fcn;
+
+	fcn = calloc(1, sizeof(*fcn));
+	if (!fcn)
+		return NULL;
+	LIST_ADDQ(&referenced_functions, &fcn->l);
+	return fcn;
+}
+
 /* Used to check an Lua function type in the stack. It creates and
  * returns a reference of the function. This function throws an
  * error if the rgument is not a "function".
@@ -6683,7 +6700,7 @@ __LJMP static int hlua_register_converters(lua_State *L)
 	sck = calloc(1, sizeof(*sck) + sizeof(struct sample_conv) * 2);
 	if (!sck)
 		WILL_LJMP(luaL_error(L, "Lua out of memory error."));
-	fcn = calloc(1, sizeof(*fcn));
+	fcn = new_hlua_function();
 	if (!fcn)
 		WILL_LJMP(luaL_error(L, "Lua out of memory error."));
 
@@ -6751,7 +6768,7 @@ __LJMP static int hlua_register_fetches(lua_State *L)
 	sfk = calloc(1, sizeof(*sfk) + sizeof(struct sample_fetch) * 2);
 	if (!sfk)
 		WILL_LJMP(luaL_error(L, "Lua out of memory error."));
-	fcn = calloc(1, sizeof(*fcn));
+	fcn = new_hlua_function();
 	if (!fcn)
 		WILL_LJMP(luaL_error(L, "Lua out of memory error."));
 
@@ -7616,7 +7633,7 @@ __LJMP static int hlua_register_action(lua_State *L)
 		akl = calloc(1, sizeof(*akl) + sizeof(struct action_kw) * 2);
 		if (!akl)
 			WILL_LJMP(luaL_error(L, "Lua out of memory error."));
-		fcn = calloc(1, sizeof(*fcn));
+		fcn = new_hlua_function();
 		if (!fcn)
 			WILL_LJMP(luaL_error(L, "Lua out of memory error."));
 
@@ -7737,7 +7754,7 @@ __LJMP static int hlua_register_service(lua_State *L)
 	akl = calloc(1, sizeof(*akl) + sizeof(struct action_kw) * 2);
 	if (!akl)
 		WILL_LJMP(luaL_error(L, "Lua out of memory error."));
-	fcn = calloc(1, sizeof(*fcn));
+	fcn = new_hlua_function();
 	if (!fcn)
 		WILL_LJMP(luaL_error(L, "Lua out of memory error."));
 
@@ -8009,7 +8026,7 @@ __LJMP static int hlua_register_cli(lua_State *L)
 	cli_kws = calloc(1, sizeof(*cli_kws) + sizeof(struct cli_kw) * 2);
 	if (!cli_kws)
 		WILL_LJMP(luaL_error(L, "Lua out of memory error."));
-	fcn = calloc(1, sizeof(*fcn));
+	fcn = new_hlua_function();
 	if (!fcn)
 		WILL_LJMP(luaL_error(L, "Lua out of memory error."));