From 314c6057b785cd94ac88905ccfce61724107d66b Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 6 Jul 2020 14:06:47 -0300
Subject: [PATCH] Avoid any code before locks in the API
For consistency in the C API, avoid any initializations before
callling lua_lock.
---
lapi.c | 26 +++++++++++++++++---------
ldo.c | 3 ++-
lstate.c | 5 +++--
3 files changed, 22 insertions(+), 12 deletions(-)
diff --git a/lapi.c b/lapi.c
index 16eb170d..9048245f 100644
--- a/lapi.c
+++ b/lapi.c
@@ -97,8 +97,9 @@ static StkId index2stack (lua_State *L, int idx) {
LUA_API int lua_checkstack (lua_State *L, int n) {
int res;
- CallInfo *ci = L->ci;
+ CallInfo *ci;
lua_lock(L);
+ ci = L->ci;
api_check(L, n >= 0, "negative 'n'");
if (L->stack_last - L->top > n) /* stack large enough? */
res = 1; /* yes; check is OK */
@@ -170,10 +171,12 @@ LUA_API int lua_gettop (lua_State *L) {
LUA_API void lua_settop (lua_State *L, int idx) {
- CallInfo *ci = L->ci;
- StkId func = ci->func;
+ CallInfo *ci;
+ StkId func;
ptrdiff_t diff; /* difference for new top */
lua_lock(L);
+ ci = L->ci;
+ func = ci->func;
if (idx >= 0) {
api_check(L, idx <= ci->top - (func + 1), "new top too large");
diff = ((func + 1) + idx) - L->top;
@@ -376,20 +379,22 @@ LUA_API int lua_toboolean (lua_State *L, int idx) {
LUA_API const char *lua_tolstring (lua_State *L, int idx, size_t *len) {
- TValue *o = index2value(L, idx);
+ TValue *o;
+ lua_lock(L);
+ o = index2value(L, idx);
if (!ttisstring(o)) {
if (!cvt2str(o)) { /* not convertible? */
if (len != NULL) *len = 0;
+ lua_unlock(L);
return NULL;
}
- lua_lock(L); /* 'luaO_tostring' may create a new string */
luaO_tostring(L, o);
luaC_checkGC(L);
o = index2value(L, idx); /* previous call may reallocate the stack */
- lua_unlock(L);
}
if (len != NULL)
*len = vslen(o);
+ lua_unlock(L);
return svalue(o);
}
@@ -625,8 +630,9 @@ static int auxgetstr (lua_State *L, const TValue *t, const char *k) {
LUA_API int lua_getglobal (lua_State *L, const char *name) {
- Table *reg = hvalue(&G(L)->l_registry);
+ Table *reg;
lua_lock(L);
+ reg = hvalue(&G(L)->l_registry);
return auxgetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
}
@@ -805,8 +811,9 @@ static void auxsetstr (lua_State *L, const TValue *t, const char *k) {
LUA_API void lua_setglobal (lua_State *L, const char *name) {
- Table *reg = hvalue(&G(L)->l_registry);
+ Table *reg;
lua_lock(L); /* unlock done in 'auxsetstr' */
+ reg = hvalue(&G(L)->l_registry);
auxsetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
}
@@ -1094,8 +1101,9 @@ LUA_API int lua_status (lua_State *L) {
LUA_API int lua_gc (lua_State *L, int what, ...) {
va_list argp;
int res = 0;
- global_State *g = G(L);
+ global_State *g;
lua_lock(L);
+ g = G(L);
va_start(argp, what);
switch (what) {
case LUA_GCSTOP: {
diff --git a/ldo.c b/ldo.c
index a89ac010..66217a4b 100644
--- a/ldo.c
+++ b/ldo.c
@@ -705,9 +705,10 @@ LUA_API int lua_isyieldable (lua_State *L) {
LUA_API int lua_yieldk (lua_State *L, int nresults, lua_KContext ctx,
lua_KFunction k) {
- CallInfo *ci = L->ci;
+ CallInfo *ci;
luai_userstateyield(L, nresults);
lua_lock(L);
+ ci = L->ci;
api_checknelems(L, nresults);
if (unlikely(!yieldable(L))) {
if (L != G(L)->mainthread)
diff --git a/lstate.c b/lstate.c
index b1f487ff..28853dc7 100644
--- a/lstate.c
+++ b/lstate.c
@@ -318,9 +318,10 @@ static void close_state (lua_State *L) {
LUA_API lua_State *lua_newthread (lua_State *L) {
- global_State *g = G(L);
+ global_State *g;
lua_State *L1;
lua_lock(L);
+ g = G(L);
luaC_checkGC(L);
/* create new thread */
L1 = &cast(LX *, luaM_newobject(L, LUA_TTHREAD, sizeof(LX)))->l;
@@ -437,8 +438,8 @@ LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
LUA_API void lua_close (lua_State *L) {
- L = G(L)->mainthread; /* only the main thread can be closed */
lua_lock(L);
+ L = G(L)->mainthread; /* only the main thread can be closed */
close_state(L);
}