Spurious debugging printf removed.

[redis.git] / src / scripting.c

diff --git a/src/scripting.c b/src/scripting.c
index 03938edd5d6979c39a98b69784695d8fb4e6a009..a5f5683e15db14bbd818fcf87561dda4f7c75c60 100644 (file)
--- a/src/scripting.c
+++ b/src/scripting.c
@@ -412,41 +412,46 @@ void luaLoadLibraries(lua_State *lua) {
 #endif
 }
 
-void scriptingProtectGlobals(lua_State *lua) {
-    char *s[26];
+/* Remove a functions that we don't want to expose to the Redis scripting
+ * environment. */
+void luaRemoveUnsupportedFunctions(lua_State *lua) {
+    lua_pushnil(lua);
+    lua_setglobal(lua,"loadfile");
+}
+
+/* This function installs metamethods in the global table _G that prevent
+ * the creation of globals accidentally.
+ *
+ * It should be the last to be called in the scripting engine initialization
+ * sequence, because it may interact with creation of globals. */
+void scriptingEnableGlobalsProtection(lua_State *lua) {
+    char *s[32];
     sds code = sdsempty();
-    int j;
+    int j = 0;
 
-    /* strict.lua from: http://metalua.luaforge.net/src/lib/strict.lua.html */
-    s[0]="local mt = getmetatable(_G)\n";
-    s[1]="if mt == nil then\n";
-    s[2]="  mt = {}\n";
-    s[3]="  setmetatable(_G, mt)\n";
-    s[4]="end\n";
-    s[5]="__STRICT = true\n";
-    s[6]="mt.__declared = {}\n";
-    s[7]="mt.__newindex = function (t, n, v)\n";
-    s[8]="  if __STRICT and not mt.__declared[n] and debug.getinfo(2) then\n";
-    s[9]="    local w = debug.getinfo(2, \"S\").what\n";
-    s[10]="    if w ~= \"main\" and w ~= \"C\" then\n";
-    s[11]="      error(\"assign to undeclared global var '\"..n..\"'\", 2)\n";
-    s[12]="    end\n";
-    s[13]="    mt.__declared[n] = true\n";
-    s[14]="  end\n";
-    s[15]="  rawset(t, n, v)\n";
-    s[16]="end\n";
-    s[17]="mt.__index = function (t, n)\n";
-    s[18]="  if debug.getinfo(2) and not mt.__declared[n] and debug.getinfo(2, \"S\").what ~= \"C\" then\n";
-    s[19]="    error(\"global var '\"..n..\"' is not declared\", 2)\n";
-    s[20]="  end\n";
-    s[21]="  return rawget(t, n)\n";
-    s[22]="end\n";
-    s[23]="function global(...)\n";
-    s[24]="   for _, v in ipairs{...} do mt.__declared[v] = true end\n";
-    s[25]="end\n";
-
-    for (j = 0; j < 26; j++) code = sdscatlen(code,s[j],strlen(s[j]));
-    luaL_loadbuffer(lua,code,sdslen(code),"strict_lua");
+    /* strict.lua from: http://metalua.luaforge.net/src/lib/strict.lua.html.
+     * Modified to be adapted to Redis. */
+    s[j++]="local mt = {}\n";
+    s[j++]="setmetatable(_G, mt)\n";
+    s[j++]="mt.__newindex = function (t, n, v)\n";
+    s[j++]="  if debug.getinfo(2) then\n";
+    s[j++]="    local w = debug.getinfo(2, \"S\").what\n";
+    s[j++]="    if w ~= \"main\" and w ~= \"C\" then\n";
+    s[j++]="      error(\"Script attempted to create global variable '\"..tostring(n)..\"'\", 2)\n";
+    s[j++]="    end\n";
+    s[j++]="  end\n";
+    s[j++]="  rawset(t, n, v)\n";
+    s[j++]="end\n";
+    s[j++]="mt.__index = function (t, n)\n";
+    s[j++]="  if debug.getinfo(2) and debug.getinfo(2, \"S\").what ~= \"C\" then\n";
+    s[j++]="    error(\"Script attempted to access unexisting global variable '\"..tostring(n)..\"'\", 2)\n";
+    s[j++]="  end\n";
+    s[j++]="  return rawget(t, n)\n";
+    s[j++]="end\n";
+    s[j++]=NULL;
+
+    for (j = 0; s[j] != NULL; j++) code = sdscatlen(code,s[j],strlen(s[j]));
+    luaL_loadbuffer(lua,code,sdslen(code),"@enable_strict_lua");
     lua_pcall(lua,0,0,0);
     sdsfree(code);
 }
@@ -457,7 +462,9 @@ void scriptingProtectGlobals(lua_State *lua) {
  * See scriptingReset() for more information. */
 void scriptingInit(void) {
     lua_State *lua = lua_open();
+
     luaLoadLibraries(lua);
+    luaRemoveUnsupportedFunctions(lua);
 
     /* Initialize a dictionary we use to map SHAs to scripts.
      * This is useful for replication, as we need to replicate EVALSHA
@@ -527,7 +534,7 @@ void scriptingInit(void) {
                                 "  if b == false then b = '' end\n"
                                 "  return a<b\n"
                                 "end\n";
-        luaL_loadbuffer(lua,compare_func,strlen(compare_func),"cmp_func_def");
+        luaL_loadbuffer(lua,compare_func,strlen(compare_func),"@cmp_func_def");
         lua_pcall(lua,0,0,0);
     }
 
@@ -543,7 +550,7 @@ void scriptingInit(void) {
     /* Lua beginners ofter don't use "local", this is likely to introduce
      * subtle bugs in their code. To prevent problems we protect accesses
      * to global variables. */
-    scriptingProtectGlobals(lua);
+    scriptingEnableGlobalsProtection(lua);
 
     server.lua = lua;
 }
@@ -678,7 +685,7 @@ int luaCreateFunction(redisClient *c, lua_State *lua, char *funcname, robj *body
     funcdef = sdscatlen(funcdef,body->ptr,sdslen(body->ptr));
     funcdef = sdscatlen(funcdef," end",4);
 
-    if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"func definition")) {
+    if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"@user_script")) {
         addReplyErrorFormat(c,"Error compiling script (new function): %s\n",
             lua_tostring(lua,-1));
         lua_pop(lua,1);