Redis 2.5.7 (2.6 RC1)

[redis.git] / src / scripting.c

diff --git a/src/scripting.c b/src/scripting.c
index f62e5c2931b764480aafa90f59231417662081fd..8c89c923c0ce4331b7136dc453141b578b870758 100644 (file)
--- a/src/scripting.c
+++ b/src/scripting.c
@@ -15,6 +15,7 @@ char *redisProtocolToLuaType_Error(lua_State *lua, char *reply);
 char *redisProtocolToLuaType_MultiBulk(lua_State *lua, char *reply);
 int redis_math_random (lua_State *L);
 int redis_math_randomseed (lua_State *L);
 char *redisProtocolToLuaType_MultiBulk(lua_State *lua, char *reply);
 int redis_math_random (lua_State *L);
 int redis_math_randomseed (lua_State *L);

+void sha1hex(char *digest, char *script, size_t len);

 
 /* Take a Redis reply in the Redis protocol format and convert it into a
  * Lua type. Thanks to this function, and the introduction of not connected
 
 /* Take a Redis reply in the Redis protocol format and convert it into a
  * Lua type. Thanks to this function, and the introduction of not connected


@@ -27,7 +28,7 @@ int redis_math_randomseed (lua_State *L);
  * is like a normal client that bypasses all the slow I/O paths.
  *
  * Note: in this function we do not do any sanity check as the reply is
  * is like a normal client that bypasses all the slow I/O paths.
  *
  * Note: in this function we do not do any sanity check as the reply is

- * generated by Redis directly. This allows use to go faster.
+ * generated by Redis directly. This allows us to go faster.

  * The reply string can be altered during the parsing as it is discared
  * after the conversion is completed.
  *
  * The reply string can be altered during the parsing as it is discared
  * after the conversion is completed.
  *


@@ -128,7 +129,38 @@ void luaPushError(lua_State *lua, char *error) {
     lua_settable(lua,-3);
 }
 
     lua_settable(lua,-3);
 }
 

-int luaRedisCommand(lua_State *lua) {
+/* Sort the array currently in the stack. We do this to make the output
+ * of commands like KEYS or SMEMBERS something deterministic when called
+ * from Lua (to play well with AOf/replication).
+ *
+ * The array is sorted using table.sort itself, and assuming all the
+ * list elements are strings. */
+void luaSortArray(lua_State *lua) {
+    /* Initial Stack: array */
+    lua_getglobal(lua,"table");
+    lua_pushstring(lua,"sort");
+    lua_gettable(lua,-2);       /* Stack: array, table, table.sort */
+    lua_pushvalue(lua,-3);      /* Stack: array, table, table.sort, array */
+    if (lua_pcall(lua,1,0,0)) {
+        /* Stack: array, table, error */
+
+        /* We are not interested in the error, we assume that the problem is
+         * that there are 'false' elements inside the array, so we try
+         * again with a slower function but able to handle this case, that
+         * is: table.sort(table, __redis__compare_helper) */
+        lua_pop(lua,1);             /* Stack: array, table */
+        lua_pushstring(lua,"sort"); /* Stack: array, table, sort */
+        lua_gettable(lua,-2);       /* Stack: array, table, table.sort */
+        lua_pushvalue(lua,-3);      /* Stack: array, table, table.sort, array */
+        lua_getglobal(lua,"__redis__compare_helper");
+        /* Stack: array, table, table.sort, array, __redis__compare_helper */
+        lua_call(lua,2,0);
+    }
+    /* Stack: array (sorted), table */
+    lua_pop(lua,1);             /* Stack: array (sorted) */
+}
+
+int luaRedisGenericCommand(lua_State *lua, int raise_error) {

     int j, argc = lua_gettop(lua);
     struct redisCommand *cmd;
     robj **argv;
     int j, argc = lua_gettop(lua);
     struct redisCommand *cmd;
     robj **argv;


@@ -175,21 +207,53 @@ int luaRedisCommand(lua_State *lua) {
         goto cleanup;
     }
 
         goto cleanup;
     }
 

+    /* There are commands that are not allowed inside scripts. */

     if (cmd->flags & REDIS_CMD_NOSCRIPT) {
         luaPushError(lua, "This Redis command is not allowed from scripts");
         goto cleanup;
     }
 
     if (cmd->flags & REDIS_CMD_NOSCRIPT) {
         luaPushError(lua, "This Redis command is not allowed from scripts");
         goto cleanup;
     }
 

-    if (cmd->flags & REDIS_CMD_WRITE && server.lua_random_dirty) {
-        luaPushError(lua,
-            "Write commands not allowed after non deterministic commands");
-        goto cleanup;
+    /* Write commands are forbidden against read-only slaves, or if a
+     * command marked as non-deterministic was already called in the context
+     * of this script. */
+    if (cmd->flags & REDIS_CMD_WRITE) {
+        if (server.lua_random_dirty) {
+            luaPushError(lua,
+                "Write commands not allowed after non deterministic commands");
+            goto cleanup;
+        } else if (server.masterhost && server.repl_slave_ro &&
+                   !(server.lua_caller->flags & REDIS_MASTER))
+        {
+            luaPushError(lua, shared.roslaveerr->ptr);
+            goto cleanup;
+        } else if (server.stop_writes_on_bgsave_err &&
+                   server.saveparamslen > 0 &&
+                   server.lastbgsave_status == REDIS_ERR)
+        {
+            luaPushError(lua, shared.bgsaveerr->ptr);
+            goto cleanup;
+        }
+    }
+
+    /* If we reached the memory limit configured via maxmemory, commands that
+     * could enlarge the memory usage are not allowed, but only if this is the
+     * first write in the context of this script, otherwise we can't stop
+     * in the middle. */
+    if (server.maxmemory && server.lua_write_dirty == 0 &&
+        (cmd->flags & REDIS_CMD_DENYOOM))
+    {
+        if (freeMemoryIfNeeded() == REDIS_ERR) {
+            luaPushError(lua, shared.oomerr->ptr);
+            goto cleanup;
+        }

     }
 
     if (cmd->flags & REDIS_CMD_RANDOM) server.lua_random_dirty = 1;
     }
 
     if (cmd->flags & REDIS_CMD_RANDOM) server.lua_random_dirty = 1;

+    if (cmd->flags & REDIS_CMD_WRITE) server.lua_write_dirty = 1;

 
     /* Run the command */
 
     /* Run the command */

-    cmd->proc(c);
+    c->cmd = cmd;
+    call(c,REDIS_CALL_SLOWLOG | REDIS_CALL_STATS);

 
     /* Convert the result of the Redis command into a suitable Lua type.
      * The first thing we need is to create a single string from the client
 
     /* Convert the result of the Redis command into a suitable Lua type.
      * The first thing we need is to create a single string from the client


@@ -205,7 +269,16 @@ int luaRedisCommand(lua_State *lua) {
         reply = sdscatlen(reply,o->ptr,sdslen(o->ptr));
         listDelNode(c->reply,listFirst(c->reply));
     }
         reply = sdscatlen(reply,o->ptr,sdslen(o->ptr));
         listDelNode(c->reply,listFirst(c->reply));
     }

+    if (raise_error && reply[0] != '-') raise_error = 0;

     redisProtocolToLuaType(lua,reply);
     redisProtocolToLuaType(lua,reply);

+    /* Sort the output array if needed, assuming it is a non-null multi bulk
+     * reply as expected. */
+    if ((cmd->flags & REDIS_CMD_SORT_FOR_SCRIPT) &&
+        (reply[0] == '*' && reply[1] != '-')) {
+        /* Skip this step if command is SORT but output was already sorted */
+        if (cmd->proc != sortCommand || server.sort_dontsort)
+            luaSortArray(lua);
+    }

     sdsfree(reply);
 
 cleanup:
     sdsfree(reply);
 
 cleanup:


@@ -215,6 +288,41 @@ cleanup:
         decrRefCount(c->argv[j]);
     zfree(c->argv);
 
         decrRefCount(c->argv[j]);
     zfree(c->argv);
 

+    if (raise_error) {
+        /* If we are here we should have an error in the stack, in the
+         * form of a table with an "err" field. Extract the string to
+         * return the plain error. */
+        lua_pushstring(lua,"err");
+        lua_gettable(lua,-2);
+        return lua_error(lua);
+    }
+    return 1;
+}
+
+int luaRedisCallCommand(lua_State *lua) {
+    return luaRedisGenericCommand(lua,1);
+}
+
+int luaRedisPCallCommand(lua_State *lua) {
+    return luaRedisGenericCommand(lua,0);
+}
+
+/* This adds redis.sha1hex(string) to Lua scripts using the same hashing
+ * function used for sha1ing lua scripts. */
+int luaRedisSha1hexCommand(lua_State *lua) {
+    int argc = lua_gettop(lua);
+    char digest[41];
+    size_t len;
+    char *s;
+
+    if (argc != 1) {
+        luaPushError(lua, "wrong number of arguments");
+        return 1;
+    }
+
+    s = (char*)lua_tolstring(lua,1,&len);
+    sha1hex(digest,s,len);
+    lua_pushstring(lua,digest);

     return 1;
 }
 
     return 1;
 }
 


@@ -256,18 +364,107 @@ int luaLogCommand(lua_State *lua) {
 void luaMaskCountHook(lua_State *lua, lua_Debug *ar) {
     long long elapsed;
     REDIS_NOTUSED(ar);
 void luaMaskCountHook(lua_State *lua, lua_Debug *ar) {
     long long elapsed;
     REDIS_NOTUSED(ar);

+    REDIS_NOTUSED(lua);

 
     elapsed = (ustime()/1000) - server.lua_time_start;
 
     elapsed = (ustime()/1000) - server.lua_time_start;

-    if (elapsed >= server.lua_time_limit) {
-        redisLog(REDIS_NOTICE,"Lua script aborted for max execution time after %lld milliseconds of running time.",elapsed);
-        lua_pushstring(lua,"Script aborted for max execution time.");
+    if (elapsed >= server.lua_time_limit && server.lua_timedout == 0) {
+        redisLog(REDIS_WARNING,"Lua slow script detected: still in execution after %lld milliseconds. You can try killing the script using the SCRIPT KILL command.",elapsed);
+        server.lua_timedout = 1;
+        /* Once the script timeouts we reenter the event loop to permit others
+         * to call SCRIPT KILL or SHUTDOWN NOSAVE if needed. For this reason
+         * we need to mask the client executing the script from the event loop.
+         * If we don't do that the client may disconnect and could no longer be
+         * here when the EVAL command will return. */
+         aeDeleteFileEvent(server.el, server.lua_caller->fd, AE_READABLE);
+    }
+    if (server.lua_timedout)
+        aeProcessEvents(server.el, AE_FILE_EVENTS|AE_DONT_WAIT);
+    if (server.lua_kill) {
+        redisLog(REDIS_WARNING,"Lua script killed by user with SCRIPT KILL.");
+        lua_pushstring(lua,"Script killed by user with SCRIPT KILL...");

         lua_error(lua);
     }
 }
 
         lua_error(lua);
     }
 }
 

+void luaLoadLib(lua_State *lua, const char *libname, lua_CFunction luafunc) {
+  lua_pushcfunction(lua, luafunc);
+  lua_pushstring(lua, libname);
+  lua_call(lua, 1, 0);
+}
+
+LUALIB_API int (luaopen_cjson) (lua_State *L);
+LUALIB_API int (luaopen_struct) (lua_State *L);
+LUALIB_API int (luaopen_cmsgpack) (lua_State *L);
+
+void luaLoadLibraries(lua_State *lua) {
+    luaLoadLib(lua, "", luaopen_base);
+    luaLoadLib(lua, LUA_TABLIBNAME, luaopen_table);
+    luaLoadLib(lua, LUA_STRLIBNAME, luaopen_string);
+    luaLoadLib(lua, LUA_MATHLIBNAME, luaopen_math);
+    luaLoadLib(lua, LUA_DBLIBNAME, luaopen_debug); 
+    luaLoadLib(lua, "cjson", luaopen_cjson);
+    luaLoadLib(lua, "struct", luaopen_struct);
+    luaLoadLib(lua, "cmsgpack", luaopen_cmsgpack);
+
+#if 0 /* Stuff that we don't load currently, for sandboxing concerns. */
+    luaLoadLib(lua, LUA_LOADLIBNAME, luaopen_package);
+    luaLoadLib(lua, LUA_OSLIBNAME, luaopen_os);
+#endif
+}
+
+/* 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 = 0;
+
+    /* 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);
+}
+
+/* Initialize the scripting environment.
+ * It is possible to call this function to reset the scripting environment
+ * assuming that we call scriptingRelease() before.
+ * See scriptingReset() for more information. */

 void scriptingInit(void) {
     lua_State *lua = lua_open();
 void scriptingInit(void) {
     lua_State *lua = lua_open();

-    luaL_openlibs(lua);
+
+    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
 
     /* Initialize a dictionary we use to map SHAs to scripts.
      * This is useful for replication, as we need to replicate EVALSHA


@@ -279,7 +476,12 @@ void scriptingInit(void) {
 
     /* redis.call */
     lua_pushstring(lua,"call");
 
     /* redis.call */
     lua_pushstring(lua,"call");

-    lua_pushcfunction(lua,luaRedisCommand);
+    lua_pushcfunction(lua,luaRedisCallCommand);
+    lua_settable(lua,-3);
+
+    /* redis.pcall */
+    lua_pushstring(lua,"pcall");
+    lua_pushcfunction(lua,luaRedisPCallCommand);

     lua_settable(lua,-3);
 
     /* redis.log and log levels. */
     lua_settable(lua,-3);
 
     /* redis.log and log levels. */


@@ -303,6 +505,11 @@ void scriptingInit(void) {
     lua_pushnumber(lua,REDIS_WARNING);
     lua_settable(lua,-3);
 
     lua_pushnumber(lua,REDIS_WARNING);
     lua_settable(lua,-3);
 

+    /* redis.sha1hex */
+    lua_pushstring(lua, "sha1hex");
+    lua_pushcfunction(lua, luaRedisSha1hexCommand);
+    lua_settable(lua, -3);
+

     /* Finally set the table as 'redis' global var. */
     lua_setglobal(lua,"redis");
 
     /* Finally set the table as 'redis' global var. */
     lua_setglobal(lua,"redis");
 


@@ -319,18 +526,54 @@ void scriptingInit(void) {
 
     lua_setglobal(lua,"math");
 
 
     lua_setglobal(lua,"math");
 

+    /* Add a helper funciton that we use to sort the multi bulk output of non
+     * deterministic commands, when containing 'false' elements. */
+    {
+        char *compare_func =    "function __redis__compare_helper(a,b)\n"
+                                "  if a == false then a = '' end\n"
+                                "  if b == false then b = '' end\n"
+                                "  return a<b\n"
+                                "end\n";
+        luaL_loadbuffer(lua,compare_func,strlen(compare_func),"@cmp_func_def");
+        lua_pcall(lua,0,0,0);
+    }
+

     /* Create the (non connected) client that we use to execute Redis commands
     /* Create the (non connected) client that we use to execute Redis commands

-     * inside the Lua interpreter */
-    server.lua_client = createClient(-1);
-    server.lua_client->flags |= REDIS_LUA_CLIENT;
+     * inside the Lua interpreter.
+     * Note: there is no need to create it again when this function is called
+     * by scriptingReset(). */
+    if (server.lua_client == NULL) {
+        server.lua_client = createClient(-1);
+        server.lua_client->flags |= REDIS_LUA_CLIENT;
+    }
+
+    /* 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. */
+    scriptingEnableGlobalsProtection(lua);

 
     server.lua = lua;
 }
 
 
     server.lua = lua;
 }
 

-/* Hash the scripit into a SHA1 digest. We use this as Lua function name.
- * Digest should point to a 41 bytes buffer: 40 for SHA1 converted into an
+/* Release resources related to Lua scripting.
+ * This function is used in order to reset the scripting environment. */
+void scriptingRelease(void) {
+    dictRelease(server.lua_scripts);
+    lua_close(server.lua);
+}
+
+void scriptingReset(void) {
+    scriptingRelease();
+    scriptingInit();
+}
+
+/* Perform the SHA1 of the input string. We use this both for hasing script
+ * bodies in order to obtain the Lua function name, and in the implementation
+ * of redis.sha1().
+ *
+ * 'digest' should point to a 41 bytes buffer: 40 for SHA1 converted into an

  * hexadecimal number, plus 1 byte for null term. */
  * hexadecimal number, plus 1 byte for null term. */

-void hashScript(char *digest, char *script, size_t len) {
+void sha1hex(char *digest, char *script, size_t len) {

     SHA1_CTX ctx;
     unsigned char hash[20];
     char *cset = "0123456789abcdef";
     SHA1_CTX ctx;
     unsigned char hash[20];
     char *cset = "0123456789abcdef";


@@ -424,10 +667,56 @@ void luaSetGlobalArray(lua_State *lua, char *var, robj **elev, int elec) {
     lua_setglobal(lua,var);
 }
 
     lua_setglobal(lua,var);
 }
 

+/* Define a lua function with the specified function name and body.
+ * The function name musts be a 2 characters long string, since all the
+ * functions we defined in the Lua context are in the form:
+ *
+ *   f_<hex sha1 sum>
+ *
+ * On success REDIS_OK is returned, and nothing is left on the Lua stack.
+ * On error REDIS_ERR is returned and an appropriate error is set in the
+ * client context. */
+int luaCreateFunction(redisClient *c, lua_State *lua, char *funcname, robj *body) {
+    sds funcdef = sdsempty();
+
+    funcdef = sdscat(funcdef,"function ");
+    funcdef = sdscatlen(funcdef,funcname,42);
+    funcdef = sdscatlen(funcdef,"() ",3);
+    funcdef = sdscatlen(funcdef,body->ptr,sdslen(body->ptr));
+    funcdef = sdscatlen(funcdef," end",4);
+
+    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);
+        sdsfree(funcdef);
+        return REDIS_ERR;
+    }
+    sdsfree(funcdef);
+    if (lua_pcall(lua,0,0,0)) {
+        addReplyErrorFormat(c,"Error running script (new function): %s\n",
+            lua_tostring(lua,-1));
+        lua_pop(lua,1);
+        return REDIS_ERR;
+    }
+
+    /* We also save a SHA1 -> Original script map in a dictionary
+     * so that we can replicate / write in the AOF all the
+     * EVALSHA commands as EVAL using the original script. */
+    {
+        int retval = dictAdd(server.lua_scripts,
+                             sdsnewlen(funcname+2,40),body);
+        redisAssertWithInfo(c,NULL,retval == DICT_OK);
+        incrRefCount(body);
+    }
+    return REDIS_OK;
+}
+

 void evalGenericCommand(redisClient *c, int evalsha) {
     lua_State *lua = server.lua;
     char funcname[43];
     long long numkeys;
 void evalGenericCommand(redisClient *c, int evalsha) {
     lua_State *lua = server.lua;
     char funcname[43];
     long long numkeys;

+    int delhook = 0;

 
     /* We want the same PRNG sequence at every call so that our PRNG is
      * not affected by external state. */
 
     /* We want the same PRNG sequence at every call so that our PRNG is
      * not affected by external state. */


@@ -442,6 +731,7 @@ void evalGenericCommand(redisClient *c, int evalsha) {
      * Thanks to this flag we'll raise an error every time a write command
      * is called after a random command was used. */
     server.lua_random_dirty = 0;
      * Thanks to this flag we'll raise an error every time a write command
      * is called after a random command was used. */
     server.lua_random_dirty = 0;

+    server.lua_write_dirty = 0;

 
     /* Get the number of arguments that are keys */
     if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)
 
     /* Get the number of arguments that are keys */
     if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)


@@ -457,7 +747,7 @@ void evalGenericCommand(redisClient *c, int evalsha) {
     funcname[1] = '_';
     if (!evalsha) {
         /* Hash the code if this is an EVAL call */
     funcname[1] = '_';
     if (!evalsha) {
         /* Hash the code if this is an EVAL call */

-        hashScript(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
+        sha1hex(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));

     } else {
         /* We already have the SHA if it is a EVALSHA */
         int j;
     } else {
         /* We already have the SHA if it is a EVALSHA */
         int j;


@@ -468,53 +758,21 @@ void evalGenericCommand(redisClient *c, int evalsha) {
         funcname[42] = '\0';
     }
 
         funcname[42] = '\0';
     }
 

+    /* Try to lookup the Lua function */

     lua_getglobal(lua, funcname);
     if (lua_isnil(lua,1)) {
     lua_getglobal(lua, funcname);
     if (lua_isnil(lua,1)) {

-        sds funcdef;
-      
+        lua_pop(lua,1); /* remove the nil from the stack */

         /* Function not defined... let's define it if we have the
          * body of the funciton. If this is an EVALSHA call we can just
          * return an error. */
         if (evalsha) {
             addReply(c, shared.noscripterr);
         /* Function not defined... let's define it if we have the
          * body of the funciton. If this is an EVALSHA call we can just
          * return an error. */
         if (evalsha) {
             addReply(c, shared.noscripterr);

-            lua_pop(lua,1); /* remove the nil from the stack */
-            return;
-        }
-        funcdef = sdsempty();
-
-        lua_pop(lua,1); /* remove the nil from the stack */
-        funcdef = sdscat(funcdef,"function ");
-        funcdef = sdscatlen(funcdef,funcname,42);
-        funcdef = sdscatlen(funcdef," ()\n",4);
-        funcdef = sdscatlen(funcdef,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
-        funcdef = sdscatlen(funcdef,"\nend\n",5);
-        /* printf("Defining:\n%s\n",funcdef); */
-
-        if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"func definition")) {
-            addReplyErrorFormat(c,"Error compiling script (new function): %s\n",
-                lua_tostring(lua,-1));
-            lua_pop(lua,1);
-            sdsfree(funcdef);
-            return;
-        }
-        sdsfree(funcdef);
-        if (lua_pcall(lua,0,0,0)) {
-            addReplyErrorFormat(c,"Error running script (new function): %s\n",
-                lua_tostring(lua,-1));
-            lua_pop(lua,1);

             return;
         }
             return;
         }

+        if (luaCreateFunction(c,lua,funcname,c->argv[1]) == REDIS_ERR) return;
+        /* Now the following is guaranteed to return non nil */

         lua_getglobal(lua, funcname);
         lua_getglobal(lua, funcname);

-
-        /* We also save a SHA1 -> Original script map in a dictionary
-         * so that we can replicate / write in the AOF all the
-         * EVALSHA commands as EVAL using the original script. */
-        {
-            int retval = dictAdd(server.lua_scripts,
-                                 sdsnewlen(funcname+2,40),c->argv[1]);
-            redisAssert(retval == DICT_OK);
-            incrRefCount(c->argv[1]);
-        }
+        redisAssert(!lua_isnil(lua,1));

     }
 
     /* Populate the argv and keys table accordingly to the arguments that
     }
 
     /* Populate the argv and keys table accordingly to the arguments that


@@ -529,17 +787,27 @@ void evalGenericCommand(redisClient *c, int evalsha) {
      * is running for too much time.
      * We set the hook only if the time limit is enabled as the hook will
      * make the Lua script execution slower. */
      * is running for too much time.
      * We set the hook only if the time limit is enabled as the hook will
      * make the Lua script execution slower. */

-    if (server.lua_time_limit > 0) {
+    server.lua_caller = c;
+    server.lua_time_start = ustime()/1000;
+    server.lua_kill = 0;
+    if (server.lua_time_limit > 0 && server.masterhost == NULL) {

         lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
         lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);

-        server.lua_time_start = ustime()/1000;
-    } else {
-        lua_sethook(lua,luaMaskCountHook,0,0);
+        delhook = 1;

     }
 
     /* At this point whatever this script was never seen before or if it was
      * already defined, we can call it. We have zero arguments and expect
      * a single return value. */
     if (lua_pcall(lua,0,1,0)) {
     }
 
     /* At this point whatever this script was never seen before or if it was
      * already defined, we can call it. We have zero arguments and expect
      * a single return value. */
     if (lua_pcall(lua,0,1,0)) {

+        if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
+        if (server.lua_timedout) {
+            server.lua_timedout = 0;
+            /* Restore the readable handler that was unregistered when the
+             * script timeout was detected. */
+            aeCreateFileEvent(server.el,c->fd,AE_READABLE,
+                              readQueryFromClient,c);
+        }
+        server.lua_caller = NULL;

         selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
         addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
             funcname, lua_tostring(lua,-1));
         selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
         addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
             funcname, lua_tostring(lua,-1));


@@ -547,6 +815,9 @@ void evalGenericCommand(redisClient *c, int evalsha) {
         lua_gc(lua,LUA_GCCOLLECT,0);
         return;
     }
         lua_gc(lua,LUA_GCCOLLECT,0);
         return;
     }

+    if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
+    server.lua_timedout = 0;
+    server.lua_caller = NULL;

     selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
     luaReplyToRedisReply(c,lua);
     lua_gc(lua,LUA_GCSTEP,1);
     selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
     luaReplyToRedisReply(c,lua);
     lua_gc(lua,LUA_GCSTEP,1);


@@ -564,7 +835,7 @@ void evalGenericCommand(redisClient *c, int evalsha) {
     if (evalsha) {
         robj *script = dictFetchValue(server.lua_scripts,c->argv[1]->ptr);
 
     if (evalsha) {
         robj *script = dictFetchValue(server.lua_scripts,c->argv[1]->ptr);
 

-        redisAssert(script != NULL);
+        redisAssertWithInfo(c,NULL,script != NULL);

         rewriteClientCommandArgument(c,0,
             resetRefCount(createStringObject("EVAL",4)));
         rewriteClientCommandArgument(c,1,script);
         rewriteClientCommandArgument(c,0,
             resetRefCount(createStringObject("EVAL",4)));
         rewriteClientCommandArgument(c,1,script);


@@ -625,3 +896,53 @@ int redis_math_randomseed (lua_State *L) {
   redisSrand48(luaL_checkint(L, 1));
   return 0;
 }
   redisSrand48(luaL_checkint(L, 1));
   return 0;
 }

+
+/* ---------------------------------------------------------------------------
+ * SCRIPT command for script environment introspection and control
+ * ------------------------------------------------------------------------- */
+
+void scriptCommand(redisClient *c) {
+    if (c->argc == 2 && !strcasecmp(c->argv[1]->ptr,"flush")) {
+        scriptingReset();
+        addReply(c,shared.ok);
+        server.dirty++; /* Replicating this command is a good idea. */
+    } else if (c->argc >= 2 && !strcasecmp(c->argv[1]->ptr,"exists")) {
+        int j;
+
+        addReplyMultiBulkLen(c, c->argc-2);
+        for (j = 2; j < c->argc; j++) {
+            if (dictFind(server.lua_scripts,c->argv[j]->ptr))
+                addReply(c,shared.cone);
+            else
+                addReply(c,shared.czero);
+        }
+    } else if (c->argc == 3 && !strcasecmp(c->argv[1]->ptr,"load")) {
+        char funcname[43];
+        sds sha;
+
+        funcname[0] = 'f';
+        funcname[1] = '_';
+        sha1hex(funcname+2,c->argv[2]->ptr,sdslen(c->argv[2]->ptr));
+        sha = sdsnewlen(funcname+2,40);
+        if (dictFind(server.lua_scripts,sha) == NULL) {
+            if (luaCreateFunction(c,server.lua,funcname,c->argv[2])
+                    == REDIS_ERR) {
+                sdsfree(sha);
+                return;
+            }
+        }
+        addReplyBulkCBuffer(c,funcname+2,40);
+        sdsfree(sha);
+    } else if (c->argc == 2 && !strcasecmp(c->argv[1]->ptr,"kill")) {
+        if (server.lua_caller == NULL) {
+            addReplyError(c,"No scripts in execution right now.");
+        } else if (server.lua_write_dirty) {
+            addReplyError(c, "Sorry the script already executed write commands against the dataset. You can either wait the script termination or kill the server in an hard way using the SHUTDOWN NOSAVE command.");
+        } else {
+            server.lua_kill = 1;
+            addReply(c,shared.ok);
+        }
+    } else {
+        addReplyError(c, "Unknown SCRIPT subcommand or wrong # of args.");
+    }
+}