From 3e41afcec550e8c5c3c4372f72efa48cbf7031a3 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 27 Nov 2009 13:37:59 -0200
Subject: [PATCH] extra api checks for number of returns of C functions and for
 lua_yield

---
 lapi.c | 5 +----
 lapi.h | 5 ++++-
 ldo.c  | 6 +++++-
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/lapi.c b/lapi.c
index 7850dcc2..694fdc35 100644
--- a/lapi.c
+++ b/lapi.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lapi.c,v 2.99 2009/11/09 18:55:17 roberto Exp roberto $
+** $Id: lapi.c,v 2.100 2009/11/09 19:10:48 roberto Exp roberto $
 ** Lua API
 ** See Copyright Notice in lua.h
 */
@@ -35,9 +35,6 @@ const char lua_ident[] =
 
 
 
-#define api_checknelems(L,n)	api_check(L, (n) < (L->top - L->ci->func), \
-				  "not enough elements in the stack")
-
 #define api_checkvalidindex(L, i)	api_check(L, (i) != luaO_nilobject, \
 					  "invalid index")
 
diff --git a/lapi.h b/lapi.h
index 8818e377..569953f4 100644
--- a/lapi.h
+++ b/lapi.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lapi.h,v 2.5 2009/04/03 15:58:03 roberto Exp roberto $
+** $Id: lapi.h,v 2.6 2009/08/31 14:26:28 roberto Exp roberto $
 ** Auxiliary functions from Lua API
 ** See Copyright Notice in lua.h
 */
@@ -17,5 +17,8 @@
 #define adjustresults(L,nres) \
     { if ((nres) == LUA_MULTRET && L->ci->top < L->top) L->ci->top = L->top; }
 
+#define api_checknelems(L,n)	api_check(L, (n) < (L->top - L->ci->func), \
+				  "not enough elements in the stack")
+
 
 #endif
diff --git a/ldo.c b/ldo.c
index 7e8f2cdb..ef1e045b 100644
--- a/ldo.c
+++ b/ldo.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldo.c,v 2.72 2009/11/17 16:46:44 roberto Exp roberto $
+** $Id: ldo.c,v 2.73 2009/11/25 15:27:51 roberto Exp roberto $
 ** Stack and Call structure of Lua
 ** See Copyright Notice in lua.h
 */
@@ -311,6 +311,7 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
     lua_unlock(L);
     n = (*curr_func(L)->c.f)(L);  /* do the actual call */
     lua_lock(L);
+    api_checknelems(L, n);
     luaD_poscall(L, L->top - n);
     return 1;
   }
@@ -382,6 +383,7 @@ static void finishCcall (lua_State *L) {
   lua_unlock(L);
   n = (*ci->u.c.k)(L);
   lua_lock(L);
+  api_checknelems(L, n);
   /* finish 'luaD_precall' */
   luaD_poscall(L, L->top - n);
 }
@@ -424,6 +426,7 @@ static void resume (lua_State *L, void *ud) {
         lua_unlock(L);
         n = (*ci->u.c.k)(L);  /* call continuation */
         lua_lock(L);
+        api_checknelems(L, n);
         firstArg = L->top - n;
       }
       G(L)->nCcalls--;  /* finish 'luaD_call' */
@@ -511,6 +514,7 @@ LUA_API int lua_yieldk (lua_State *L, int nresults, int ctx, lua_CFunction k) {
   CallInfo *ci = L->ci;
   luai_userstateyield(L, nresults);
   lua_lock(L);
+  api_checknelems(L, nresults);
   if (L->nny > 0)
     luaG_runerror(L, "attempt to yield across metamethod/C-call boundary");
   L->status = LUA_YIELD;