src/scripting.c

   1 #include "redis.h"
   2 #include "sha1.h"
   3
   4 #include <lua.h>
   5 #include <lauxlib.h>
   6 #include <lualib.h>
   7 #include <ctype.h>
   8
   9 char *redisProtocolToLuaType_Int(lua_State *lua, char *reply);
  10 char *redisProtocolToLuaType_Bulk(lua_State *lua, char *reply);
  11 char *redisProtocolToLuaType_Status(lua_State *lua, char *reply);
  12 char *redisProtocolToLuaType_Error(lua_State *lua, char *reply);
  13 char *redisProtocolToLuaType_MultiBulk(lua_State *lua, char *reply);
  14
  15 /* Take a Redis reply in the Redis protocol format and convert it into a
  16  * Lua type. Thanks to this function, and the introduction of not connected
  17  * clients, it is trvial to implement the redis() lua function.
  18  *
  19  * Basically we take the arguments, execute the Redis command in the context
  20  * of a non connected client, then take the generated reply and convert it
  21  * into a suitable Lua type. With this trick the scripting feature does not
  22  * need the introduction of a full Redis internals API. Basically the script
  23  * is like a normal client that bypasses all the slow I/O paths.
  24  *
  25  * Note: in this function we do not do any sanity check as the reply is
  26  * generated by Redis directly. This allows use to go faster.
  27  * The reply string can be altered during the parsing as it is discared
  28  * after the conversion is completed.
  29  *
  30  * Errors are returned as a table with a single 'err' field set to the
  31  * error string.
  32  */
  33
  34 char *redisProtocolToLuaType(lua_State *lua, char* reply) {
  35     char *p = reply;
  36
  37     switch(*p) {
  38     case ':':
  39         p = redisProtocolToLuaType_Int(lua,reply);
  40         break;
  41     case '$':
  42         p = redisProtocolToLuaType_Bulk(lua,reply);
  43         break;
  44     case '+':
  45         p = redisProtocolToLuaType_Status(lua,reply);
  46         break;
  47     case '-':
  48         p = redisProtocolToLuaType_Error(lua,reply);
  49         break;
  50     case '*':
  51         p = redisProtocolToLuaType_MultiBulk(lua,reply);
  52         break;
  53     }
  54     return p;
  55 }
  56
  57 char *redisProtocolToLuaType_Int(lua_State *lua, char *reply) {
  58     char *p = strchr(reply+1,'\r');
  59     long long value;
  60
  61     string2ll(reply+1,p-reply-1,&value);
  62     lua_pushnumber(lua,(lua_Number)value);
  63     return p+2;
  64 }
  65
  66 char *redisProtocolToLuaType_Bulk(lua_State *lua, char *reply) {
  67     char *p = strchr(reply+1,'\r');
  68     long long bulklen;
  69
  70     string2ll(reply+1,p-reply-1,&bulklen);
  71     if (bulklen == -1) {
  72         lua_pushboolean(lua,0);
  73         return p+2;
  74     } else {
  75         lua_pushlstring(lua,p+2,bulklen);
  76         return p+2+bulklen+2;
  77     }
  78 }
  79
  80 char *redisProtocolToLuaType_Status(lua_State *lua, char *reply) {
  81     char *p = strchr(reply+1,'\r');
  82
  83     lua_newtable(lua);
  84     lua_pushstring(lua,"ok");
  85     lua_pushlstring(lua,reply+1,p-reply-1);
  86     lua_settable(lua,-3);
  87     return p+2;
  88 }
  89
  90 char *redisProtocolToLuaType_Error(lua_State *lua, char *reply) {
  91     char *p = strchr(reply+1,'\r');
  92
  93     lua_newtable(lua);
  94     lua_pushstring(lua,"err");
  95     lua_pushlstring(lua,reply+1,p-reply-1);
  96     lua_settable(lua,-3);
  97     return p+2;
  98 }
  99
 100 char *redisProtocolToLuaType_MultiBulk(lua_State *lua, char *reply) {
 101     char *p = strchr(reply+1,'\r');
 102     long long mbulklen;
 103     int j = 0;
 104
 105     string2ll(reply+1,p-reply-1,&mbulklen);
 106     p += 2;
 107     if (mbulklen == -1) {
 108         lua_pushboolean(lua,0);
 109         return p;
 110     }
 111     lua_newtable(lua);
 112     for (j = 0; j < mbulklen; j++) {
 113         lua_pushnumber(lua,j+1);
 114         p = redisProtocolToLuaType(lua,p);
 115         lua_settable(lua,-3);
 116     }
 117     return p;
 118 }
 119
 120 void luaPushError(lua_State *lua, char *error) {
 121     lua_newtable(lua);
 122     lua_pushstring(lua,"err");
 123     lua_pushstring(lua, error);
 124     lua_settable(lua,-3);
 125 }
 126
 127 int luaRedisCommand(lua_State *lua) {
 128     int j, argc = lua_gettop(lua);
 129     struct redisCommand *cmd;
 130     robj **argv;
 131     redisClient *c = server.lua_client;
 132     sds reply;
 133
 134     /* Build the arguments vector */
 135     argv = zmalloc(sizeof(robj*)*argc);
 136     for (j = 0; j < argc; j++) {
 137         if (!lua_isstring(lua,j+1)) break;
 138         argv[j] = createStringObject((char*)lua_tostring(lua,j+1),
 139                                      lua_strlen(lua,j+1));
 140     }
 141
 142     /* Check if one of the arguments passed by the Lua script
 143      * is not a string or an integer (lua_isstring() return true for
 144      * integers as well). */
 145     if (j != argc) {
 146         j--;
 147         while (j >= 0) {
 148             decrRefCount(argv[j]);
 149             j--;
 150         }
 151         zfree(argv);
 152         luaPushError(lua,
 153             "Lua redis() command arguments must be strings or integers");
 154         return 1;
 155     }
 156
 157     /* Command lookup */
 158     cmd = lookupCommand(argv[0]->ptr);
 159     if (!cmd || ((cmd->arity > 0 && cmd->arity != argc) ||
 160                    (argc < -cmd->arity)))
 161     {
 162         for (j = 0; j < argc; j++) decrRefCount(argv[j]);
 163         zfree(argv);
 164         if (cmd)
 165             luaPushError(lua,
 166                 "Wrong number of args calling Redis command From Lua script");
 167         else
 168             luaPushError(lua,"Unknown Redis command called from Lua script");
 169         return 1;
 170     }
 171
 172     /* Run the command in the context of a fake client */
 173     c->argv = argv;
 174     c->argc = argc;
 175     cmd->proc(c);
 176
 177     /* Convert the result of the Redis command into a suitable Lua type.
 178      * The first thing we need is to create a single string from the client
 179      * output buffers. */
 180     reply = sdsempty();
 181     if (c->bufpos) {
 182         reply = sdscatlen(reply,c->buf,c->bufpos);
 183         c->bufpos = 0;
 184     }
 185     while(listLength(c->reply)) {
 186         robj *o = listNodeValue(listFirst(c->reply));
 187
 188         reply = sdscatlen(reply,o->ptr,sdslen(o->ptr));
 189         listDelNode(c->reply,listFirst(c->reply));
 190     }
 191     redisProtocolToLuaType(lua,reply);
 192     sdsfree(reply);
 193
 194     /* Clean up. Command code may have changed argv/argc so we use the
 195      * argv/argc of the client instead of the local variables. */
 196     for (j = 0; j < c->argc; j++)
 197         decrRefCount(c->argv[j]);
 198     zfree(c->argv);
 199
 200     return 1;
 201 }
 202
 203 void luaMaskCountHook(lua_State *lua, lua_Debug *ar) {
 204     long long elapsed;
 205     REDIS_NOTUSED(ar);
 206
 207     elapsed = (ustime()/1000) - server.lua_time_start;
 208     if (elapsed >= server.lua_time_limit) {
 209         redisLog(REDIS_NOTICE,"Lua script aborted for max execution time after %lld milliseconds of running time.",elapsed);
 210         lua_pushstring(lua,"Script aborted for max execution time.");
 211         lua_error(lua);
 212     }
 213 }
 214
 215 void scriptingInit(void) {
 216     lua_State *lua = lua_open();
 217     luaL_openlibs(lua);
 218
 219     /* Register the 'r' command */
 220     lua_pushcfunction(lua,luaRedisCommand);
 221     lua_setglobal(lua,"redis");
 222
 223     /* Create the (non connected) client that we use to execute Redis commands
 224      * inside the Lua interpreter */
 225     server.lua_client = createClient(-1);
 226     server.lua_client->flags |= REDIS_LUA_CLIENT;
 227
 228     server.lua = lua;
 229 }
 230
 231 /* Hash the scripit into a SHA1 digest. We use this as Lua function name.
 232  * Digest should point to a 41 bytes buffer: 40 for SHA1 converted into an
 233  * hexadecimal number, plus 1 byte for null term. */
 234 void hashScript(char *digest, char *script, size_t len) {
 235     SHA1_CTX ctx;
 236     unsigned char hash[20];
 237     char *cset = "0123456789abcdef";
 238     int j;
 239
 240     SHA1Init(&ctx);
 241     SHA1Update(&ctx,(unsigned char*)script,len);
 242     SHA1Final(hash,&ctx);
 243
 244     for (j = 0; j < 20; j++) {
 245         digest[j*2] = cset[((hash[j]&0xF0)>>4)];
 246         digest[j*2+1] = cset[(hash[j]&0xF)];
 247     }
 248     digest[40] = '\0';
 249 }
 250
 251 void luaReplyToRedisReply(redisClient *c, lua_State *lua) {
 252     int t = lua_type(lua,-1);
 253
 254     switch(t) {
 255     case LUA_TSTRING:
 256         addReplyBulkCBuffer(c,(char*)lua_tostring(lua,-1),lua_strlen(lua,-1));
 257         break;
 258     case LUA_TBOOLEAN:
 259         addReply(c,lua_toboolean(lua,-1) ? shared.cone : shared.nullbulk);
 260         break;
 261     case LUA_TNUMBER:
 262         addReplyLongLong(c,(long long)lua_tonumber(lua,-1));
 263         break;
 264     case LUA_TTABLE:
 265         /* We need to check if it is an array, an error, or a status reply.
 266          * Error are returned as a single element table with 'err' field.
 267          * Status replies are returned as single elment table with 'ok' field */
 268         lua_pushstring(lua,"err");
 269         lua_gettable(lua,-2);
 270         t = lua_type(lua,-1);
 271         if (t == LUA_TSTRING) {
 272             addReplySds(c,sdscatprintf(sdsempty(),
 273                     "-%s\r\n",(char*)lua_tostring(lua,-1)));
 274             lua_pop(lua,2);
 275             return;
 276         }
 277
 278         lua_pop(lua,1);
 279         lua_pushstring(lua,"ok");
 280         lua_gettable(lua,-2);
 281         t = lua_type(lua,-1);
 282         if (t == LUA_TSTRING) {
 283             addReplySds(c,sdscatprintf(sdsempty(),
 284                     "+%s\r\n",(char*)lua_tostring(lua,-1)));
 285             lua_pop(lua,1);
 286         } else {
 287             void *replylen = addDeferredMultiBulkLength(c);
 288             int j = 1, mbulklen = 0;
 289
 290             lua_pop(lua,1); /* Discard the 'ok' field value we popped */
 291             while(1) {
 292                 lua_pushnumber(lua,j++);
 293                 lua_gettable(lua,-2);
 294                 t = lua_type(lua,-1);
 295                 if (t == LUA_TNIL) {
 296                     lua_pop(lua,1);
 297                     break;
 298                 }
 299                 luaReplyToRedisReply(c, lua);
 300                 mbulklen++;
 301             }
 302             setDeferredMultiBulkLength(c,replylen,mbulklen);
 303         }
 304         break;
 305     default:
 306         addReply(c,shared.nullbulk);
 307     }
 308     lua_pop(lua,1);
 309 }
 310
 311 /* Set an array of Redis String Objects as a Lua array (table) stored into a
 312  * global variable. */
 313 void luaSetGlobalArray(lua_State *lua, char *var, robj **elev, int elec) {
 314     int j;
 315
 316     lua_newtable(lua);
 317     for (j = 0; j < elec; j++) {
 318         lua_pushlstring(lua,(char*)elev[j]->ptr,sdslen(elev[j]->ptr));
 319         lua_rawseti(lua,-2,j+1);
 320     }
 321     lua_setglobal(lua,var);
 322 }
 323
 324 void evalGenericCommand(redisClient *c, int evalsha) {
 325     lua_State *lua = server.lua;
 326     char funcname[43];
 327     long long numkeys;
 328
 329     /* Get the number of arguments that are keys */
 330     if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)
 331         return;
 332     if (numkeys > (c->argc - 3)) {
 333         addReplyError(c,"Number of keys can't be greater than number of args");
 334         return;
 335     }
 336
 337     /* We obtain the script SHA1, then check if this function is already
 338      * defined into the Lua state */
 339     funcname[0] = 'f';
 340     funcname[1] = '_';
 341     if (!evalsha) {
 342         /* Hash the code if this is an EVAL call */
 343         hashScript(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
 344     } else {
 345         /* We already have the SHA if it is a EVALSHA */
 346         int j;
 347         char *sha = c->argv[1]->ptr;
 348
 349         for (j = 0; j < 40; j++)
 350             funcname[j+2] = tolower(sha[j]);
 351         funcname[42] = '\0';
 352     }
 353
 354     lua_getglobal(lua, funcname);
 355     if (lua_isnil(lua,1)) {
 356         sds funcdef;
 357
 358         /* Function not defined... let's define it if we have the
 359          * body of the funciton. If this is an EVALSHA call we can just
 360          * return an error. */
 361         if (evalsha) {
 362             addReply(c, shared.noscripterr);
 363             lua_pop(lua,1); /* remove the nil from the stack */
 364             return;
 365         }
 366         funcdef = sdsempty();
 367
 368         lua_pop(lua,1); /* remove the nil from the stack */
 369         funcdef = sdscat(funcdef,"function ");
 370         funcdef = sdscatlen(funcdef,funcname,42);
 371         funcdef = sdscatlen(funcdef," ()\n",4);
 372         funcdef = sdscatlen(funcdef,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
 373         funcdef = sdscatlen(funcdef,"\nend\n",5);
 374         /* printf("Defining:\n%s\n",funcdef); */
 375
 376         if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"func definition")) {
 377             addReplyErrorFormat(c,"Error compiling script (new function): %s\n",
 378                 lua_tostring(lua,-1));
 379             lua_pop(lua,1);
 380             sdsfree(funcdef);
 381             return;
 382         }
 383         sdsfree(funcdef);
 384         if (lua_pcall(lua,0,0,0)) {
 385             addReplyErrorFormat(c,"Error running script (new function): %s\n",
 386                 lua_tostring(lua,-1));
 387             lua_pop(lua,1);
 388             return;
 389         }
 390         lua_getglobal(lua, funcname);
 391     }
 392
 393     /* Populate the argv and keys table accordingly to the arguments that
 394      * EVAL received. */
 395     luaSetGlobalArray(lua,"KEYS",c->argv+3,numkeys);
 396     luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argc-3-numkeys);
 397
 398     /* Select the right DB in the context of the Lua client */
 399     selectDb(server.lua_client,c->db->id);
 400
 401     /* Set an hook in order to be able to stop the script execution if it
 402      * is running for too much time.
 403      * We set the hook only if the time limit is enabled as the hook will
 404      * make the Lua script execution slower. */
 405     if (server.lua_time_limit > 0) {
 406         lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
 407         server.lua_time_start = ustime()/1000;
 408     } else {
 409         lua_sethook(lua,luaMaskCountHook,0,0);
 410     }
 411
 412     /* At this point whatever this script was never seen before or if it was
 413      * already defined, we can call it. We have zero arguments and expect
 414      * a single return value. */
 415     if (lua_pcall(lua,0,1,0)) {
 416         selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
 417         addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
 418             funcname, lua_tostring(lua,-1));
 419         lua_pop(lua,1);
 420         lua_gc(lua,LUA_GCCOLLECT,0);
 421         return;
 422     }
 423     selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
 424     luaReplyToRedisReply(c,lua);
 425     lua_gc(lua,LUA_GCSTEP,1);
 426 }
 427
 428 void evalCommand(redisClient *c) {
 429     evalGenericCommand(c,0);
 430 }
 431
 432 void evalShaCommand(redisClient *c) {
 433     if (sdslen(c->argv[1]->ptr) != 40) {
 434         /* We know that a match is not possible if the provided SHA is
 435          * not the right length. So we return an error ASAP, this way
 436          * evalGenericCommand() can be implemented without string length
 437          * sanity check */
 438         addReply(c, shared.noscripterr);
 439         return;
 440     }
 441     evalGenericCommand(c,1);
 442 }