A reimplementation of blocking operation internals.

[redis.git] / src / scripting.c

diff --git a/src/scripting.c b/src/scripting.c
index e38d08077d0c88757498da41eb052e4717162afb..35b654f7739c490b806cbe5896d30766cbb98ad9 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++) {


@@ -274,11 +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


@@ -306,6 +313,25 @@ 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;
+}
+

 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;


@@ -392,13 +418,59 @@ 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


@@ -439,6 +511,11 @@ 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");
 


@@ -463,7 +540,7 @@ 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);
     }
 


@@ -476,6 +553,11 @@ 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;
 }
 


@@ -491,10 +573,13 @@ 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";


@@ -606,7 +691,7 @@ 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);


@@ -637,6 +722,7 @@ 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. */


@@ -667,7 +753,7 @@ 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;


@@ -707,19 +793,19 @@ 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


@@ -735,6 +821,7 @@ 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 */


@@ -841,7 +928,7 @@ 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])