Warn when configured maxmemory value seems odd.

[redis.git] / src / scripting.c

diff --git a/src/scripting.c b/src/scripting.c
index 9d41a45f22dc83d19cb967082f97005c8e19e227..13f608e67cfe23c6819f9e76f1adc78d7033a026 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


@@ -166,6 +167,13 @@ int luaRedisGenericCommand(lua_State *lua, int raise_error) {
     redisClient *c = server.lua_client;
     sds reply;
 
     redisClient *c = server.lua_client;
     sds reply;
 

+    /* Require at least one argument */
+    if (argc == 0) {
+        luaPushError(lua,
+            "Please specify at least one argument for redis.call()");
+        return 1;
+    }
+

     /* Build the arguments vector */
     argv = zmalloc(sizeof(robj*)*argc);
     for (j = 0; j < argc; j++) {
     /* Build the arguments vector */
     argv = zmalloc(sizeof(robj*)*argc);
     for (j = 0; j < argc; j++) {


@@ -206,15 +214,45 @@ int luaRedisGenericCommand(lua_State *lua, int raise_error) {
         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;


@@ -244,11 +282,10 @@ int luaRedisGenericCommand(lua_State *lua, int raise_error) {
      * reply as expected. */
     if ((cmd->flags & REDIS_CMD_SORT_FOR_SCRIPT) &&
         (reply[0] == '*' && reply[1] != '-')) {
      * 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);
             luaSortArray(lua);
     }
     sdsfree(reply);

+    c->reply_bytes = 0;

 
 cleanup:
     /* Clean up. Command code may have changed argv/argc so we use the
 
 cleanup:
     /* Clean up. Command code may have changed argv/argc so we use the


@@ -276,6 +313,53 @@ int luaRedisPCallCommand(lua_State *lua) {
     return luaRedisGenericCommand(lua,0);
 }
 
     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;
+}
+
+/* Returns a table with a single field 'field' set to the string value
+ * passed as argument. This helper function is handy when returning
+ * a Redis Protocol error or status reply from Lua:
+ *
+ * return redis.error_reply("ERR Some Error")
+ * return redis.status_reply("ERR Some Error")
+ */
+int luaRedisReturnSingleFieldTable(lua_State *lua, char *field) {
+    if (lua_gettop(lua) != 1 || lua_type(lua,-1) != LUA_TSTRING) {
+        luaPushError(lua, "wrong number or type of arguments");
+        return 1;
+    }
+
+    lua_newtable(lua);
+    lua_pushstring(lua, field);
+    lua_pushvalue(lua, -3);
+    lua_settable(lua, -3);
+    return 1;
+}
+
+int luaRedisErrorReplyCommand(lua_State *lua) {
+    return luaRedisReturnSingleFieldTable(lua,"err");
+}
+
+int luaRedisStatusReplyCommand(lua_State *lua) {
+    return luaRedisReturnSingleFieldTable(lua,"ok");
+}
+

 int luaLogCommand(lua_State *lua) {
     int j, argc = lua_gettop(lua);
     int level;
 int luaLogCommand(lua_State *lua) {
     int j, argc = lua_gettop(lua);
     int level;


@@ -344,6 +428,7 @@ void luaLoadLib(lua_State *lua, const char *libname, lua_CFunction luafunc) {
 
 LUALIB_API int (luaopen_cjson) (lua_State *L);
 LUALIB_API int (luaopen_struct) (lua_State *L);
 
 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);
 
 void luaLoadLibraries(lua_State *lua) {
     luaLoadLib(lua, "", luaopen_base);


@@ -353,6 +438,7 @@ void luaLoadLibraries(lua_State *lua) {
     luaLoadLib(lua, LUA_DBLIBNAME, luaopen_debug); 
     luaLoadLib(lua, "cjson", luaopen_cjson);
     luaLoadLib(lua, "struct", luaopen_struct);
     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);
 
 #if 0 /* Stuff that we don't load currently, for sandboxing concerns. */
     luaLoadLib(lua, LUA_LOADLIBNAME, luaopen_package);


@@ -360,13 +446,59 @@ void luaLoadLibraries(lua_State *lua) {
 #endif
 }
 
 #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();
 /* 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();

+

     luaLoadLibraries(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


@@ -407,6 +539,19 @@ 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);
+
+    /* redis.error_reply and redis.status_reply */
+    lua_pushstring(lua, "error_reply");
+    lua_pushcfunction(lua, luaRedisErrorReplyCommand);
+    lua_settable(lua, -3);
+    lua_pushstring(lua, "status_reply");
+    lua_pushcfunction(lua, luaRedisStatusReplyCommand);
+    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");
 


@@ -431,7 +576,7 @@ void scriptingInit(void) {
                                 "  if b == false then b = '' end\n"
                                 "  return a<b\n"
                                 "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");
+        luaL_loadbuffer(lua,compare_func,strlen(compare_func),"@cmp_func_def");

         lua_pcall(lua,0,0,0);
     }
 
         lua_pcall(lua,0,0,0);
     }
 


@@ -444,6 +589,11 @@ void scriptingInit(void) {
         server.lua_client->flags |= REDIS_LUA_CLIENT;
     }
 
         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;
 }
 


@@ -459,10 +609,13 @@ void scriptingReset(void) {
     scriptingInit();
 }
 
     scriptingInit();
 }
 

-/* 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
+/* 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";


@@ -574,7 +727,7 @@ int luaCreateFunction(redisClient *c, lua_State *lua, char *funcname, robj *body
     funcdef = sdscatlen(funcdef,body->ptr,sdslen(body->ptr));
     funcdef = sdscatlen(funcdef," end",4);
 
     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);
         addReplyErrorFormat(c,"Error compiling script (new function): %s\n",
             lua_tostring(lua,-1));
         lua_pop(lua,1);


@@ -605,6 +758,7 @@ void evalGenericCommand(redisClient *c, int evalsha) {
     lua_State *lua = server.lua;
     char funcname[43];
     long long numkeys;
     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. */


@@ -635,7 +789,7 @@ 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;


@@ -675,19 +829,19 @@ 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. */

+    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);
     if (server.lua_time_limit > 0 && server.masterhost == NULL) {
         lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);

-    } 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. */
     }
 
     /* 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. */

-    server.lua_caller = c;
-    server.lua_time_start = ustime()/1000;
-    server.lua_kill = 0;

     if (lua_pcall(lua,0,1,0)) {
     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
         if (server.lua_timedout) {
             server.lua_timedout = 0;
             /* Restore the readable handler that was unregistered when the


@@ -703,6 +857,7 @@ 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 */
     server.lua_timedout = 0;
     server.lua_caller = NULL;
     selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */


@@ -809,7 +964,7 @@ void scriptCommand(redisClient *c) {
 
         funcname[0] = 'f';
         funcname[1] = '_';
 
         funcname[0] = 'f';
         funcname[1] = '_';

-        hashScript(funcname+2,c->argv[2]->ptr,sdslen(c->argv[2]->ptr));
+        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])
         sha = sdsnewlen(funcname+2,40);
         if (dictFind(server.lua_scripts,sha) == NULL) {
             if (luaCreateFunction(c,server.lua,funcname,c->argv[2])