src/scripting.c

   1 #include "redis.h"
   2 #include "sha1.h"
   3 #include "rand.h"
   4
   5 #include <lua.h>
   6 #include <lauxlib.h>
   7 #include <lualib.h>
   8 #include <ctype.h>
   9 #include <math.h>
  10
  11 char *redisProtocolToLuaType_Int(lua_State *lua, char *reply);
  12 char *redisProtocolToLuaType_Bulk(lua_State *lua, char *reply);
  13 char *redisProtocolToLuaType_Status(lua_State *lua, char *reply);
  14 char *redisProtocolToLuaType_Error(lua_State *lua, char *reply);
  15 char *redisProtocolToLuaType_MultiBulk(lua_State *lua, char *reply);
  16 int redis_math_random (lua_State *L);
  17 int redis_math_randomseed (lua_State *L);
  18
  19 /* Take a Redis reply in the Redis protocol format and convert it into a
  20  * Lua type. Thanks to this function, and the introduction of not connected
  21  * clients, it is trvial to implement the redis() lua function.
  22  *
  23  * Basically we take the arguments, execute the Redis command in the context
  24  * of a non connected client, then take the generated reply and convert it
  25  * into a suitable Lua type. With this trick the scripting feature does not
  26  * need the introduction of a full Redis internals API. Basically the script
  27  * is like a normal client that bypasses all the slow I/O paths.
  28  *
  29  * Note: in this function we do not do any sanity check as the reply is
  30  * generated by Redis directly. This allows use to go faster.
  31  * The reply string can be altered during the parsing as it is discared
  32  * after the conversion is completed.
  33  *
  34  * Errors are returned as a table with a single 'err' field set to the
  35  * error string.
  36  */
  37
  38 char *redisProtocolToLuaType(lua_State *lua, char* reply) {
  39     char *p = reply;
  40
  41     switch(*p) {
  42     case ':':
  43         p = redisProtocolToLuaType_Int(lua,reply);
  44         break;
  45     case '$':
  46         p = redisProtocolToLuaType_Bulk(lua,reply);
  47         break;
  48     case '+':
  49         p = redisProtocolToLuaType_Status(lua,reply);
  50         break;
  51     case '-':
  52         p = redisProtocolToLuaType_Error(lua,reply);
  53         break;
  54     case '*':
  55         p = redisProtocolToLuaType_MultiBulk(lua,reply);
  56         break;
  57     }
  58     return p;
  59 }
  60
  61 char *redisProtocolToLuaType_Int(lua_State *lua, char *reply) {
  62     char *p = strchr(reply+1,'\r');
  63     long long value;
  64
  65     string2ll(reply+1,p-reply-1,&value);
  66     lua_pushnumber(lua,(lua_Number)value);
  67     return p+2;
  68 }
  69
  70 char *redisProtocolToLuaType_Bulk(lua_State *lua, char *reply) {
  71     char *p = strchr(reply+1,'\r');
  72     long long bulklen;
  73
  74     string2ll(reply+1,p-reply-1,&bulklen);
  75     if (bulklen == -1) {
  76         lua_pushboolean(lua,0);
  77         return p+2;
  78     } else {
  79         lua_pushlstring(lua,p+2,bulklen);
  80         return p+2+bulklen+2;
  81     }
  82 }
  83
  84 char *redisProtocolToLuaType_Status(lua_State *lua, char *reply) {
  85     char *p = strchr(reply+1,'\r');
  86
  87     lua_newtable(lua);
  88     lua_pushstring(lua,"ok");
  89     lua_pushlstring(lua,reply+1,p-reply-1);
  90     lua_settable(lua,-3);
  91     return p+2;
  92 }
  93
  94 char *redisProtocolToLuaType_Error(lua_State *lua, char *reply) {
  95     char *p = strchr(reply+1,'\r');
  96
  97     lua_newtable(lua);
  98     lua_pushstring(lua,"err");
  99     lua_pushlstring(lua,reply+1,p-reply-1);
 100     lua_settable(lua,-3);
 101     return p+2;
 102 }
 103
 104 char *redisProtocolToLuaType_MultiBulk(lua_State *lua, char *reply) {
 105     char *p = strchr(reply+1,'\r');
 106     long long mbulklen;
 107     int j = 0;
 108
 109     string2ll(reply+1,p-reply-1,&mbulklen);
 110     p += 2;
 111     if (mbulklen == -1) {
 112         lua_pushboolean(lua,0);
 113         return p;
 114     }
 115     lua_newtable(lua);
 116     for (j = 0; j < mbulklen; j++) {
 117         lua_pushnumber(lua,j+1);
 118         p = redisProtocolToLuaType(lua,p);
 119         lua_settable(lua,-3);
 120     }
 121     return p;
 122 }
 123
 124 void luaPushError(lua_State *lua, char *error) {
 125     lua_newtable(lua);
 126     lua_pushstring(lua,"err");
 127     lua_pushstring(lua, error);
 128     lua_settable(lua,-3);
 129 }
 130
 131 int luaRedisCommand(lua_State *lua) {
 132     int j, argc = lua_gettop(lua);
 133     struct redisCommand *cmd;
 134     robj **argv;
 135     redisClient *c = server.lua_client;
 136     sds reply;
 137
 138     /* Build the arguments vector */
 139     argv = zmalloc(sizeof(robj*)*argc);
 140     for (j = 0; j < argc; j++) {
 141         if (!lua_isstring(lua,j+1)) break;
 142         argv[j] = createStringObject((char*)lua_tostring(lua,j+1),
 143                                      lua_strlen(lua,j+1));
 144     }
 145
 146     /* Check if one of the arguments passed by the Lua script
 147      * is not a string or an integer (lua_isstring() return true for
 148      * integers as well). */
 149     if (j != argc) {
 150         j--;
 151         while (j >= 0) {
 152             decrRefCount(argv[j]);
 153             j--;
 154         }
 155         zfree(argv);
 156         luaPushError(lua,
 157             "Lua redis() command arguments must be strings or integers");
 158         return 1;
 159     }
 160
 161     /* Setup our fake client for command execution */
 162     c->argv = argv;
 163     c->argc = argc;
 164
 165     /* Command lookup */
 166     cmd = lookupCommand(argv[0]->ptr);
 167     if (!cmd || ((cmd->arity > 0 && cmd->arity != argc) ||
 168                    (argc < -cmd->arity)))
 169     {
 170         if (cmd)
 171             luaPushError(lua,
 172                 "Wrong number of args calling Redis command From Lua script");
 173         else
 174             luaPushError(lua,"Unknown Redis command called from Lua script");
 175         goto cleanup;
 176     }
 177
 178     if (cmd->flags & REDIS_CMD_NOSCRIPT) {
 179         luaPushError(lua, "This Redis command is not allowed from scripts");
 180         goto cleanup;
 181     }
 182
 183     /* Run the command */
 184     cmd->proc(c);
 185
 186     /* Convert the result of the Redis command into a suitable Lua type.
 187      * The first thing we need is to create a single string from the client
 188      * output buffers. */
 189     reply = sdsempty();
 190     if (c->bufpos) {
 191         reply = sdscatlen(reply,c->buf,c->bufpos);
 192         c->bufpos = 0;
 193     }
 194     while(listLength(c->reply)) {
 195         robj *o = listNodeValue(listFirst(c->reply));
 196
 197         reply = sdscatlen(reply,o->ptr,sdslen(o->ptr));
 198         listDelNode(c->reply,listFirst(c->reply));
 199     }
 200     redisProtocolToLuaType(lua,reply);
 201     sdsfree(reply);
 202
 203 cleanup:
 204     /* Clean up. Command code may have changed argv/argc so we use the
 205      * argv/argc of the client instead of the local variables. */
 206     for (j = 0; j < c->argc; j++)
 207         decrRefCount(c->argv[j]);
 208     zfree(c->argv);
 209
 210     return 1;
 211 }
 212
 213 int luaLogCommand(lua_State *lua) {
 214     int j, argc = lua_gettop(lua);
 215     int level;
 216     sds log;
 217
 218     if (argc < 2) {
 219         luaPushError(lua, "redis.log() requires two arguments or more.");
 220         return 1;
 221     } else if (!lua_isnumber(lua,-argc)) {
 222         luaPushError(lua, "First argument must be a number (log level).");
 223         return 1;
 224     }
 225     level = lua_tonumber(lua,-argc);
 226     if (level < REDIS_DEBUG || level > REDIS_WARNING) {
 227         luaPushError(lua, "Invalid debug level.");
 228         return 1;
 229     }
 230
 231     /* Glue together all the arguments */
 232     log = sdsempty();
 233     for (j = 1; j < argc; j++) {
 234         size_t len;
 235         char *s;
 236
 237         s = (char*)lua_tolstring(lua,(-argc)+j,&len);
 238         if (s) {
 239             if (j != 1) log = sdscatlen(log," ",1);
 240             log = sdscatlen(log,s,len);
 241         }
 242     }
 243     redisLogRaw(level,log);
 244     sdsfree(log);
 245     return 0;
 246 }
 247
 248 void luaMaskCountHook(lua_State *lua, lua_Debug *ar) {
 249     long long elapsed;
 250     REDIS_NOTUSED(ar);
 251
 252     elapsed = (ustime()/1000) - server.lua_time_start;
 253     if (elapsed >= server.lua_time_limit) {
 254         redisLog(REDIS_NOTICE,"Lua script aborted for max execution time after %lld milliseconds of running time.",elapsed);
 255         lua_pushstring(lua,"Script aborted for max execution time.");
 256         lua_error(lua);
 257     }
 258 }
 259
 260 void scriptingInit(void) {
 261     lua_State *lua = lua_open();
 262     luaL_openlibs(lua);
 263
 264     /* Initialize a dictionary we use to map SHAs to scripts.
 265      * This is useful for replication, as we need to replicate EVALSHA
 266      * as EVAL, so we need to remember the associated script. */
 267     server.lua_scripts = dictCreate(&dbDictType,NULL);
 268
 269     /* Register the redis commands table and fields */
 270     lua_newtable(lua);
 271
 272     /* redis.call */
 273     lua_pushstring(lua,"call");
 274     lua_pushcfunction(lua,luaRedisCommand);
 275     lua_settable(lua,-3);
 276
 277     /* redis.log and log levels. */
 278     lua_pushstring(lua,"log");
 279     lua_pushcfunction(lua,luaLogCommand);
 280     lua_settable(lua,-3);
 281
 282     lua_pushstring(lua,"LOG_DEBUG");
 283     lua_pushnumber(lua,REDIS_DEBUG);
 284     lua_settable(lua,-3);
 285
 286     lua_pushstring(lua,"LOG_VERBOSE");
 287     lua_pushnumber(lua,REDIS_VERBOSE);
 288     lua_settable(lua,-3);
 289
 290     lua_pushstring(lua,"LOG_NOTICE");
 291     lua_pushnumber(lua,REDIS_NOTICE);
 292     lua_settable(lua,-3);
 293
 294     lua_pushstring(lua,"LOG_WARNING");
 295     lua_pushnumber(lua,REDIS_WARNING);
 296     lua_settable(lua,-3);
 297
 298     /* Finally set the table as 'redis' global var. */
 299     lua_setglobal(lua,"redis");
 300
 301     /* Replace math.random and math.randomseed with our implementations. */
 302     lua_getglobal(lua,"math");
 303
 304     lua_pushstring(lua,"random");
 305     lua_pushcfunction(lua,redis_math_random);
 306     lua_settable(lua,-3);
 307
 308     lua_pushstring(lua,"randomseed");
 309     lua_pushcfunction(lua,redis_math_randomseed);
 310     lua_settable(lua,-3);
 311
 312     lua_setglobal(lua,"math");
 313
 314     /* Create the (non connected) client that we use to execute Redis commands
 315      * inside the Lua interpreter */
 316     server.lua_client = createClient(-1);
 317     server.lua_client->flags |= REDIS_LUA_CLIENT;
 318
 319     server.lua = lua;
 320 }
 321
 322 /* Hash the scripit into a SHA1 digest. We use this as Lua function name.
 323  * Digest should point to a 41 bytes buffer: 40 for SHA1 converted into an
 324  * hexadecimal number, plus 1 byte for null term. */
 325 void hashScript(char *digest, char *script, size_t len) {
 326     SHA1_CTX ctx;
 327     unsigned char hash[20];
 328     char *cset = "0123456789abcdef";
 329     int j;
 330
 331     SHA1Init(&ctx);
 332     SHA1Update(&ctx,(unsigned char*)script,len);
 333     SHA1Final(hash,&ctx);
 334
 335     for (j = 0; j < 20; j++) {
 336         digest[j*2] = cset[((hash[j]&0xF0)>>4)];
 337         digest[j*2+1] = cset[(hash[j]&0xF)];
 338     }
 339     digest[40] = '\0';
 340 }
 341
 342 void luaReplyToRedisReply(redisClient *c, lua_State *lua) {
 343     int t = lua_type(lua,-1);
 344
 345     switch(t) {
 346     case LUA_TSTRING:
 347         addReplyBulkCBuffer(c,(char*)lua_tostring(lua,-1),lua_strlen(lua,-1));
 348         break;
 349     case LUA_TBOOLEAN:
 350         addReply(c,lua_toboolean(lua,-1) ? shared.cone : shared.nullbulk);
 351         break;
 352     case LUA_TNUMBER:
 353         addReplyLongLong(c,(long long)lua_tonumber(lua,-1));
 354         break;
 355     case LUA_TTABLE:
 356         /* We need to check if it is an array, an error, or a status reply.
 357          * Error are returned as a single element table with 'err' field.
 358          * Status replies are returned as single elment table with 'ok' field */
 359         lua_pushstring(lua,"err");
 360         lua_gettable(lua,-2);
 361         t = lua_type(lua,-1);
 362         if (t == LUA_TSTRING) {
 363             sds err = sdsnew(lua_tostring(lua,-1));
 364             sdsmapchars(err,"\r\n","  ",2);
 365             addReplySds(c,sdscatprintf(sdsempty(),"-%s\r\n",err));
 366             sdsfree(err);
 367             lua_pop(lua,2);
 368             return;
 369         }
 370
 371         lua_pop(lua,1);
 372         lua_pushstring(lua,"ok");
 373         lua_gettable(lua,-2);
 374         t = lua_type(lua,-1);
 375         if (t == LUA_TSTRING) {
 376             sds ok = sdsnew(lua_tostring(lua,-1));
 377             sdsmapchars(ok,"\r\n","  ",2);
 378             addReplySds(c,sdscatprintf(sdsempty(),"+%s\r\n",ok));
 379             sdsfree(ok);
 380             lua_pop(lua,1);
 381         } else {
 382             void *replylen = addDeferredMultiBulkLength(c);
 383             int j = 1, mbulklen = 0;
 384
 385             lua_pop(lua,1); /* Discard the 'ok' field value we popped */
 386             while(1) {
 387                 lua_pushnumber(lua,j++);
 388                 lua_gettable(lua,-2);
 389                 t = lua_type(lua,-1);
 390                 if (t == LUA_TNIL) {
 391                     lua_pop(lua,1);
 392                     break;
 393                 }
 394                 luaReplyToRedisReply(c, lua);
 395                 mbulklen++;
 396             }
 397             setDeferredMultiBulkLength(c,replylen,mbulklen);
 398         }
 399         break;
 400     default:
 401         addReply(c,shared.nullbulk);
 402     }
 403     lua_pop(lua,1);
 404 }
 405
 406 /* Set an array of Redis String Objects as a Lua array (table) stored into a
 407  * global variable. */
 408 void luaSetGlobalArray(lua_State *lua, char *var, robj **elev, int elec) {
 409     int j;
 410
 411     lua_newtable(lua);
 412     for (j = 0; j < elec; j++) {
 413         lua_pushlstring(lua,(char*)elev[j]->ptr,sdslen(elev[j]->ptr));
 414         lua_rawseti(lua,-2,j+1);
 415     }
 416     lua_setglobal(lua,var);
 417 }
 418
 419 void evalGenericCommand(redisClient *c, int evalsha) {
 420     lua_State *lua = server.lua;
 421     char funcname[43];
 422     long long numkeys;
 423
 424     /* We want the same PRNG sequence at every call so that our PRNG is
 425      * not affected by external state. */
 426     redisSrand48(0);
 427
 428     /* Get the number of arguments that are keys */
 429     if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)
 430         return;
 431     if (numkeys > (c->argc - 3)) {
 432         addReplyError(c,"Number of keys can't be greater than number of args");
 433         return;
 434     }
 435
 436     /* We obtain the script SHA1, then check if this function is already
 437      * defined into the Lua state */
 438     funcname[0] = 'f';
 439     funcname[1] = '_';
 440     if (!evalsha) {
 441         /* Hash the code if this is an EVAL call */
 442         hashScript(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
 443     } else {
 444         /* We already have the SHA if it is a EVALSHA */
 445         int j;
 446         char *sha = c->argv[1]->ptr;
 447
 448         for (j = 0; j < 40; j++)
 449             funcname[j+2] = tolower(sha[j]);
 450         funcname[42] = '\0';
 451     }
 452
 453     lua_getglobal(lua, funcname);
 454     if (lua_isnil(lua,1)) {
 455         sds funcdef;
 456
 457         /* Function not defined... let's define it if we have the
 458          * body of the funciton. If this is an EVALSHA call we can just
 459          * return an error. */
 460         if (evalsha) {
 461             addReply(c, shared.noscripterr);
 462             lua_pop(lua,1); /* remove the nil from the stack */
 463             return;
 464         }
 465         funcdef = sdsempty();
 466
 467         lua_pop(lua,1); /* remove the nil from the stack */
 468         funcdef = sdscat(funcdef,"function ");
 469         funcdef = sdscatlen(funcdef,funcname,42);
 470         funcdef = sdscatlen(funcdef," ()\n",4);
 471         funcdef = sdscatlen(funcdef,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
 472         funcdef = sdscatlen(funcdef,"\nend\n",5);
 473         /* printf("Defining:\n%s\n",funcdef); */
 474
 475         if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"func definition")) {
 476             addReplyErrorFormat(c,"Error compiling script (new function): %s\n",
 477                 lua_tostring(lua,-1));
 478             lua_pop(lua,1);
 479             sdsfree(funcdef);
 480             return;
 481         }
 482         sdsfree(funcdef);
 483         if (lua_pcall(lua,0,0,0)) {
 484             addReplyErrorFormat(c,"Error running script (new function): %s\n",
 485                 lua_tostring(lua,-1));
 486             lua_pop(lua,1);
 487             return;
 488         }
 489         lua_getglobal(lua, funcname);
 490
 491         /* We also save a SHA1 -> Original script map in a dictionary
 492          * so that we can replicate / write in the AOF all the
 493          * EVALSHA commands as EVAL using the original script. */
 494         {
 495             int retval = dictAdd(server.lua_scripts,
 496                                  sdsnewlen(funcname+2,40),c->argv[1]);
 497             redisAssert(retval == DICT_OK);
 498             incrRefCount(c->argv[1]);
 499         }
 500     }
 501
 502     /* Populate the argv and keys table accordingly to the arguments that
 503      * EVAL received. */
 504     luaSetGlobalArray(lua,"KEYS",c->argv+3,numkeys);
 505     luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argc-3-numkeys);
 506
 507     /* Select the right DB in the context of the Lua client */
 508     selectDb(server.lua_client,c->db->id);
 509
 510     /* Set an hook in order to be able to stop the script execution if it
 511      * is running for too much time.
 512      * We set the hook only if the time limit is enabled as the hook will
 513      * make the Lua script execution slower. */
 514     if (server.lua_time_limit > 0) {
 515         lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
 516         server.lua_time_start = ustime()/1000;
 517     } else {
 518         lua_sethook(lua,luaMaskCountHook,0,0);
 519     }
 520
 521     /* At this point whatever this script was never seen before or if it was
 522      * already defined, we can call it. We have zero arguments and expect
 523      * a single return value. */
 524     if (lua_pcall(lua,0,1,0)) {
 525         selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
 526         addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
 527             funcname, lua_tostring(lua,-1));
 528         lua_pop(lua,1);
 529         lua_gc(lua,LUA_GCCOLLECT,0);
 530         return;
 531     }
 532     selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
 533     luaReplyToRedisReply(c,lua);
 534     lua_gc(lua,LUA_GCSTEP,1);
 535
 536     /* If we have slaves attached we want to replicate this command as
 537      * EVAL instead of EVALSHA. We do this also in the AOF as currently there
 538      * is no easy way to propagate a command in a different way in the AOF
 539      * and in the replication link.
 540      *
 541      * IMPROVEMENT POSSIBLE:
 542      * 1) Replicate this command as EVALSHA in the AOF.
 543      * 2) Remember what slave already received a given script, and replicate
 544      *    the EVALSHA against this slaves when possible.
 545      */
 546     if (evalsha) {
 547         robj *script = dictFetchValue(server.lua_scripts,c->argv[1]->ptr);
 548
 549         redisAssert(script != NULL);
 550         rewriteClientCommandArgument(c,0,
 551             resetRefCount(createStringObject("EVAL",4)));
 552         rewriteClientCommandArgument(c,1,script);
 553     }
 554 }
 555
 556 void evalCommand(redisClient *c) {
 557     evalGenericCommand(c,0);
 558 }
 559
 560 void evalShaCommand(redisClient *c) {
 561     if (sdslen(c->argv[1]->ptr) != 40) {
 562         /* We know that a match is not possible if the provided SHA is
 563          * not the right length. So we return an error ASAP, this way
 564          * evalGenericCommand() can be implemented without string length
 565          * sanity check */
 566         addReply(c, shared.noscripterr);
 567         return;
 568     }
 569     evalGenericCommand(c,1);
 570 }
 571
 572 /* We replace math.random() with our implementation that is not affected
 573  * by specific libc random() implementations and will output the same sequence
 574  * (for the same seed) in every arch. */
 575
 576 /* The following implementation is the one shipped with Lua itself but with
 577  * rand() replaced by redisLrand48(). */
 578 int redis_math_random (lua_State *L) {
 579   /* the `%' avoids the (rare) case of r==1, and is needed also because on
 580      some systems (SunOS!) `rand()' may return a value larger than RAND_MAX */
 581   lua_Number r = (lua_Number)(redisLrand48()%REDIS_LRAND48_MAX) /
 582                                 (lua_Number)REDIS_LRAND48_MAX;
 583   switch (lua_gettop(L)) {  /* check number of arguments */
 584     case 0: {  /* no arguments */
 585       lua_pushnumber(L, r);  /* Number between 0 and 1 */
 586       break;
 587     }
 588     case 1: {  /* only upper limit */
 589       int u = luaL_checkint(L, 1);
 590       luaL_argcheck(L, 1<=u, 1, "interval is empty");
 591       lua_pushnumber(L, floor(r*u)+1);  /* int between 1 and `u' */
 592       break;
 593     }
 594     case 2: {  /* lower and upper limits */
 595       int l = luaL_checkint(L, 1);
 596       int u = luaL_checkint(L, 2);
 597       luaL_argcheck(L, l<=u, 2, "interval is empty");
 598       lua_pushnumber(L, floor(r*(u-l+1))+l);  /* int between `l' and `u' */
 599       break;
 600     }
 601     default: return luaL_error(L, "wrong number of arguments");
 602   }
 603   return 1;
 604 }
 605
 606 int redis_math_randomseed (lua_State *L) {
 607   redisSrand48(luaL_checkint(L, 1));
 608   return 0;
 609 }