Avoid using addresses of static variables as unique keys
The addresses of static variables may be different for different
instances of Lua, making these instances incompatible if they use
these addresses as unique keys in the registry (or other tables).
diff --git a/ldblib.c b/ldblib.c
index 513a13c..6415839 100644
--- a/ldblib.c
+++ b/ldblib.c
@@ -21,10 +21,10 @@
/*
-** The hook table at registry[&HOOKKEY] maps threads to their current
-** hook function. (We only need the unique address of 'HOOKKEY'.)
+** The hook table at registry[HOOKKEY] maps threads to their current
+** hook function.
*/
-static const int HOOKKEY = 0;
+static const char* HOOKKEY = "_HOOKKEY";
/*
@@ -314,7 +314,7 @@
static void hookf (lua_State *L, lua_Debug *ar) {
static const char *const hooknames[] =
{"call", "return", "line", "count", "tail call"};
- lua_rawgetp(L, LUA_REGISTRYINDEX, &HOOKKEY);
+ lua_getfield(L, LUA_REGISTRYINDEX, HOOKKEY);
lua_pushthread(L);
if (lua_rawget(L, -2) == LUA_TFUNCTION) { /* is there a hook function? */
lua_pushstring(L, hooknames[(int)ar->event]); /* push event name */
@@ -367,14 +367,12 @@
count = (int)luaL_optinteger(L, arg + 3, 0);
func = hookf; mask = makemask(smask, count);
}
- if (lua_rawgetp(L, LUA_REGISTRYINDEX, &HOOKKEY) == LUA_TNIL) {
- lua_createtable(L, 0, 2); /* create a hook table */
- lua_pushvalue(L, -1);
- lua_rawsetp(L, LUA_REGISTRYINDEX, &HOOKKEY); /* set it in position */
+ if (!luaL_getsubtable(L, LUA_REGISTRYINDEX, HOOKKEY)) {
+ /* table just created; initialize it */
lua_pushstring(L, "k");
lua_setfield(L, -2, "__mode"); /** hooktable.__mode = "k" */
lua_pushvalue(L, -1);
- lua_setmetatable(L, -2); /* setmetatable(hooktable) = hooktable */
+ lua_setmetatable(L, -2); /* metatable(hooktable) = hooktable */
}
checkstack(L, L1, 1);
lua_pushthread(L1); lua_xmove(L1, L, 1); /* key (thread) */
@@ -396,7 +394,7 @@
else if (hook != hookf) /* external hook? */
lua_pushliteral(L, "external hook");
else { /* hook table must exist */
- lua_rawgetp(L, LUA_REGISTRYINDEX, &HOOKKEY);
+ lua_getfield(L, LUA_REGISTRYINDEX, HOOKKEY);
checkstack(L, L1, 1);
lua_pushthread(L1); lua_xmove(L1, L, 1);
lua_rawget(L, -2); /* 1st result = hooktable[L1] */
diff --git a/loadlib.c b/loadlib.c
index b72dd88..9ef0027 100644
--- a/loadlib.c
+++ b/loadlib.c
@@ -56,10 +56,10 @@
/*
-** unique key for table in the registry that keeps handles
+** key for table in the registry that keeps handles
** for all loaded C libraries
*/
-static const int CLIBS = 0;
+static const char *CLIBS = "_CLIBS";
#define LIB_FAIL "open"
@@ -327,7 +327,7 @@
*/
static void *checkclib (lua_State *L, const char *path) {
void *plib;
- lua_rawgetp(L, LUA_REGISTRYINDEX, &CLIBS);
+ lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
lua_getfield(L, -1, path);
plib = lua_touserdata(L, -1); /* plib = CLIBS[path] */
lua_pop(L, 2); /* pop CLIBS table and 'plib' */
@@ -340,7 +340,7 @@
** registry.CLIBS[#CLIBS + 1] = plib -- also keep a list of all libraries
*/
static void addtoclib (lua_State *L, const char *path, void *plib) {
- lua_rawgetp(L, LUA_REGISTRYINDEX, &CLIBS);
+ lua_getfield(L, LUA_REGISTRYINDEX, CLIBS);
lua_pushlightuserdata(L, plib);
lua_pushvalue(L, -1);
lua_setfield(L, -3, path); /* CLIBS[path] = plib */
@@ -716,12 +716,11 @@
** setting a finalizer to close all libraries when closing state.
*/
static void createclibstable (lua_State *L) {
- lua_newtable(L); /* create CLIBS table */
+ luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS); /* create CLIBS table */
lua_createtable(L, 0, 1); /* create metatable for CLIBS */
lua_pushcfunction(L, gctm);
lua_setfield(L, -2, "__gc"); /* set finalizer for CLIBS table */
lua_setmetatable(L, -2);
- lua_rawsetp(L, LUA_REGISTRYINDEX, &CLIBS); /* set CLIBS table in registry */
}
diff --git a/testes/db.lua b/testes/db.lua
index 3d94f77..a64a113 100644
--- a/testes/db.lua
+++ b/testes/db.lua
@@ -255,6 +255,10 @@
end
+-- hook table has weak keys
+assert(getmetatable(debug.getregistry()._HOOKKEY).__mode == 'k')
+
+
a = {}; L = nil
local glob = 1
local oldglob = glob
