redis.c

   1 /*
   2  * Copyright (c) 2006-2009, Salvatore Sanfilippo <antirez at gmail dot com>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are met:
   7  *
   8  *   * Redistributions of source code must retain the above copyright notice,
   9  *     this list of conditions and the following disclaimer.
  10  *   * Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  *   * Neither the name of Redis nor the names of its contributors may be used
  14  *     to endorse or promote products derived from this software without
  15  *     specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  18  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  21  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  27  * POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #define REDIS_VERSION "0.100"
  31
  32 #include "fmacros.h"
  33
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <time.h>
  38 #include <unistd.h>
  39 #include <signal.h>
  40 #include <sys/wait.h>
  41 #include <errno.h>
  42 #include <assert.h>
  43 #include <ctype.h>
  44 #include <stdarg.h>
  45 #include <inttypes.h>
  46 #include <arpa/inet.h>
  47 #include <sys/stat.h>
  48 #include <fcntl.h>
  49 #include <sys/time.h>
  50 #include <sys/resource.h>
  51 #include <limits.h>
  52
  53 #include "ae.h"     /* Event driven programming library */
  54 #include "sds.h"    /* Dynamic safe strings */
  55 #include "anet.h"   /* Networking the easy way */
  56 #include "dict.h"   /* Hash tables */
  57 #include "adlist.h" /* Linked lists */
  58 #include "zmalloc.h" /* total memory usage aware version of malloc/free */
  59 #include "lzf.h"
  60
  61 /* Error codes */
  62 #define REDIS_OK                0
  63 #define REDIS_ERR               -1
  64
  65 /* Static server configuration */
  66 #define REDIS_SERVERPORT        6379    /* TCP port */
  67 #define REDIS_MAXIDLETIME       (60*5)  /* default client timeout */
  68 #define REDIS_IOBUF_LEN         1024
  69 #define REDIS_LOADBUF_LEN       1024
  70 #define REDIS_STATIC_ARGS       4
  71 #define REDIS_DEFAULT_DBNUM     16
  72 #define REDIS_CONFIGLINE_MAX    1024
  73 #define REDIS_OBJFREELIST_MAX   1000000 /* Max number of objects to cache */
  74 #define REDIS_MAX_SYNC_TIME     60      /* Slave can't take more to sync */
  75 #define REDIS_EXPIRELOOKUPS_PER_CRON    100 /* try to expire 100 keys/second */
  76
  77 /* Hash table parameters */
  78 #define REDIS_HT_MINFILL        10      /* Minimal hash table fill 10% */
  79 #define REDIS_HT_MINSLOTS       16384   /* Never resize the HT under this */
  80
  81 /* Command flags */
  82 #define REDIS_CMD_BULK          1
  83 #define REDIS_CMD_INLINE        2
  84
  85 /* Object types */
  86 #define REDIS_STRING 0
  87 #define REDIS_LIST 1
  88 #define REDIS_SET 2
  89 #define REDIS_HASH 3
  90
  91 /* Object types only used for dumping to disk */
  92 #define REDIS_EXPIRETIME 253
  93 #define REDIS_SELECTDB 254
  94 #define REDIS_EOF 255
  95
  96 /* Defines related to the dump file format. To store 32 bits lengths for short
  97  * keys requires a lot of space, so we check the most significant 2 bits of
  98  * the first byte to interpreter the length:
  99  *
 100  * 00|000000 => if the two MSB are 00 the len is the 6 bits of this byte
 101  * 01|000000 00000000 =>  01, the len is 14 byes, 6 bits + 8 bits of next byte
 102  * 10|000000 [32 bit integer] => if it's 01, a full 32 bit len will follow
 103  * 11|000000 this means: specially encoded object will follow. The six bits
 104  *           number specify the kind of object that follows.
 105  *           See the REDIS_RDB_ENC_* defines.
 106  *
 107  * Lenghts up to 63 are stored using a single byte, most DB keys, and may
 108  * values, will fit inside. */
 109 #define REDIS_RDB_6BITLEN 0
 110 #define REDIS_RDB_14BITLEN 1
 111 #define REDIS_RDB_32BITLEN 2
 112 #define REDIS_RDB_ENCVAL 3
 113 #define REDIS_RDB_LENERR UINT_MAX
 114
 115 /* When a length of a string object stored on disk has the first two bits
 116  * set, the remaining two bits specify a special encoding for the object
 117  * accordingly to the following defines: */
 118 #define REDIS_RDB_ENC_INT8 0        /* 8 bit signed integer */
 119 #define REDIS_RDB_ENC_INT16 1       /* 16 bit signed integer */
 120 #define REDIS_RDB_ENC_INT32 2       /* 32 bit signed integer */
 121 #define REDIS_RDB_ENC_LZF 3         /* string compressed with FASTLZ */
 122
 123 /* Client flags */
 124 #define REDIS_CLOSE 1       /* This client connection should be closed ASAP */
 125 #define REDIS_SLAVE 2       /* This client is a slave server */
 126 #define REDIS_MASTER 4      /* This client is a master server */
 127 #define REDIS_MONITOR 8      /* This client is a slave monitor, see MONITOR */
 128
 129 /* Slave replication state - slave side */
 130 #define REDIS_REPL_NONE 0   /* No active replication */
 131 #define REDIS_REPL_CONNECT 1    /* Must connect to master */
 132 #define REDIS_REPL_CONNECTED 2  /* Connected to master */
 133
 134 /* Slave replication state - from the point of view of master
 135  * Note that in SEND_BULK and ONLINE state the slave receives new updates
 136  * in its output queue. In the WAIT_BGSAVE state instead the server is waiting
 137  * to start the next background saving in order to send updates to it. */
 138 #define REDIS_REPL_WAIT_BGSAVE_START 3 /* master waits bgsave to start feeding it */
 139 #define REDIS_REPL_WAIT_BGSAVE_END 4 /* master waits bgsave to start bulk DB transmission */
 140 #define REDIS_REPL_SEND_BULK 5 /* master is sending the bulk DB */
 141 #define REDIS_REPL_ONLINE 6 /* bulk DB already transmitted, receive updates */
 142
 143 /* List related stuff */
 144 #define REDIS_HEAD 0
 145 #define REDIS_TAIL 1
 146
 147 /* Sort operations */
 148 #define REDIS_SORT_GET 0
 149 #define REDIS_SORT_DEL 1
 150 #define REDIS_SORT_INCR 2
 151 #define REDIS_SORT_DECR 3
 152 #define REDIS_SORT_ASC 4
 153 #define REDIS_SORT_DESC 5
 154 #define REDIS_SORTKEY_MAX 1024
 155
 156 /* Log levels */
 157 #define REDIS_DEBUG 0
 158 #define REDIS_NOTICE 1
 159 #define REDIS_WARNING 2
 160
 161 /* Anti-warning macro... */
 162 #define REDIS_NOTUSED(V) ((void) V)
 163
 164 /*================================= Data types ============================== */
 165
 166 /* A redis object, that is a type able to hold a string / list / set */
 167 typedef struct redisObject {
 168     void *ptr;
 169     int type;
 170     int refcount;
 171 } robj;
 172
 173 typedef struct redisDb {
 174     dict *dict;
 175     dict *expires;
 176     int id;
 177 } redisDb;
 178
 179 /* With multiplexing we need to take per-clinet state.
 180  * Clients are taken in a liked list. */
 181 typedef struct redisClient {
 182     int fd;
 183     redisDb *db;
 184     int dictid;
 185     sds querybuf;
 186     robj **argv;
 187     int argc;
 188     int bulklen;            /* bulk read len. -1 if not in bulk read mode */
 189     list *reply;
 190     int sentlen;
 191     time_t lastinteraction; /* time of the last interaction, used for timeout */
 192     int flags;              /* REDIS_CLOSE | REDIS_SLAVE | REDIS_MONITOR */
 193     int slaveseldb;         /* slave selected db, if this client is a slave */
 194     int authenticated;      /* when requirepass is non-NULL */
 195     int replstate;          /* replication state if this is a slave */
 196     int repldbfd;           /* replication DB file descriptor */
 197     long repldboff;          /* replication DB file offset */
 198     off_t repldbsize;       /* replication DB file size */
 199 } redisClient;
 200
 201 struct saveparam {
 202     time_t seconds;
 203     int changes;
 204 };
 205
 206 /* Global server state structure */
 207 struct redisServer {
 208     int port;
 209     int fd;
 210     redisDb *db;
 211     dict *sharingpool;
 212     unsigned int sharingpoolsize;
 213     long long dirty;            /* changes to DB from the last save */
 214     list *clients;
 215     list *slaves, *monitors;
 216     char neterr[ANET_ERR_LEN];
 217     aeEventLoop *el;
 218     int cronloops;              /* number of times the cron function run */
 219     list *objfreelist;          /* A list of freed objects to avoid malloc() */
 220     time_t lastsave;            /* Unix time of last save succeeede */
 221     size_t usedmemory;             /* Used memory in megabytes */
 222     /* Fields used only for stats */
 223     time_t stat_starttime;         /* server start time */
 224     long long stat_numcommands;    /* number of processed commands */
 225     long long stat_numconnections; /* number of connections received */
 226     /* Configuration */
 227     int verbosity;
 228     int glueoutputbuf;
 229     int maxidletime;
 230     int dbnum;
 231     int daemonize;
 232     char *pidfile;
 233     int bgsaveinprogress;
 234     struct saveparam *saveparams;
 235     int saveparamslen;
 236     char *logfile;
 237     char *bindaddr;
 238     char *dbfilename;
 239     char *requirepass;
 240     int shareobjects;
 241     /* Replication related */
 242     int isslave;
 243     char *masterhost;
 244     int masterport;
 245     redisClient *master;    /* client that is master for this slave */
 246     int replstate;
 247     /* Sort parameters - qsort_r() is only available under BSD so we
 248      * have to take this state global, in order to pass it to sortCompare() */
 249     int sort_desc;
 250     int sort_alpha;
 251     int sort_bypattern;
 252 };
 253
 254 typedef void redisCommandProc(redisClient *c);
 255 struct redisCommand {
 256     char *name;
 257     redisCommandProc *proc;
 258     int arity;
 259     int flags;
 260 };
 261
 262 typedef struct _redisSortObject {
 263     robj *obj;
 264     union {
 265         double score;
 266         robj *cmpobj;
 267     } u;
 268 } redisSortObject;
 269
 270 typedef struct _redisSortOperation {
 271     int type;
 272     robj *pattern;
 273 } redisSortOperation;
 274
 275 struct sharedObjectsStruct {
 276     robj *crlf, *ok, *err, *emptybulk, *czero, *cone, *pong, *space,
 277     *colon, *nullbulk, *nullmultibulk,
 278     *emptymultibulk, *wrongtypeerr, *nokeyerr, *syntaxerr, *sameobjecterr,
 279     *outofrangeerr, *plus,
 280     *select0, *select1, *select2, *select3, *select4,
 281     *select5, *select6, *select7, *select8, *select9;
 282 } shared;
 283
 284 /*================================ Prototypes =============================== */
 285
 286 static void freeStringObject(robj *o);
 287 static void freeListObject(robj *o);
 288 static void freeSetObject(robj *o);
 289 static void decrRefCount(void *o);
 290 static robj *createObject(int type, void *ptr);
 291 static void freeClient(redisClient *c);
 292 static int rdbLoad(char *filename);
 293 static void addReply(redisClient *c, robj *obj);
 294 static void addReplySds(redisClient *c, sds s);
 295 static void incrRefCount(robj *o);
 296 static int rdbSaveBackground(char *filename);
 297 static robj *createStringObject(char *ptr, size_t len);
 298 static void replicationFeedSlaves(list *slaves, struct redisCommand *cmd, int dictid, robj **argv, int argc);
 299 static int syncWithMaster(void);
 300 static robj *tryObjectSharing(robj *o);
 301 static int removeExpire(redisDb *db, robj *key);
 302 static int expireIfNeeded(redisDb *db, robj *key);
 303 static int deleteIfVolatile(redisDb *db, robj *key);
 304 static int deleteKey(redisDb *db, robj *key);
 305 static time_t getExpire(redisDb *db, robj *key);
 306 static int setExpire(redisDb *db, robj *key, time_t when);
 307 static void updateSalvesWaitingBgsave(int bgsaveerr);
 308
 309 static void authCommand(redisClient *c);
 310 static void pingCommand(redisClient *c);
 311 static void echoCommand(redisClient *c);
 312 static void setCommand(redisClient *c);
 313 static void setnxCommand(redisClient *c);
 314 static void getCommand(redisClient *c);
 315 static void delCommand(redisClient *c);
 316 static void existsCommand(redisClient *c);
 317 static void incrCommand(redisClient *c);
 318 static void decrCommand(redisClient *c);
 319 static void incrbyCommand(redisClient *c);
 320 static void decrbyCommand(redisClient *c);
 321 static void selectCommand(redisClient *c);
 322 static void randomkeyCommand(redisClient *c);
 323 static void keysCommand(redisClient *c);
 324 static void dbsizeCommand(redisClient *c);
 325 static void lastsaveCommand(redisClient *c);
 326 static void saveCommand(redisClient *c);
 327 static void bgsaveCommand(redisClient *c);
 328 static void shutdownCommand(redisClient *c);
 329 static void moveCommand(redisClient *c);
 330 static void renameCommand(redisClient *c);
 331 static void renamenxCommand(redisClient *c);
 332 static void lpushCommand(redisClient *c);
 333 static void rpushCommand(redisClient *c);
 334 static void lpopCommand(redisClient *c);
 335 static void rpopCommand(redisClient *c);
 336 static void llenCommand(redisClient *c);
 337 static void lindexCommand(redisClient *c);
 338 static void lrangeCommand(redisClient *c);
 339 static void ltrimCommand(redisClient *c);
 340 static void typeCommand(redisClient *c);
 341 static void lsetCommand(redisClient *c);
 342 static void saddCommand(redisClient *c);
 343 static void sremCommand(redisClient *c);
 344 static void smoveCommand(redisClient *c);
 345 static void sismemberCommand(redisClient *c);
 346 static void scardCommand(redisClient *c);
 347 static void sinterCommand(redisClient *c);
 348 static void sinterstoreCommand(redisClient *c);
 349 static void sunionCommand(redisClient *c);
 350 static void sunionstoreCommand(redisClient *c);
 351 static void syncCommand(redisClient *c);
 352 static void flushdbCommand(redisClient *c);
 353 static void flushallCommand(redisClient *c);
 354 static void sortCommand(redisClient *c);
 355 static void lremCommand(redisClient *c);
 356 static void infoCommand(redisClient *c);
 357 static void mgetCommand(redisClient *c);
 358 static void monitorCommand(redisClient *c);
 359 static void expireCommand(redisClient *c);
 360 static void getSetCommand(redisClient *c);
 361
 362 /*================================= Globals ================================= */
 363
 364 /* Global vars */
 365 static struct redisServer server; /* server global state */
 366 static struct redisCommand cmdTable[] = {
 367     {"get",getCommand,2,REDIS_CMD_INLINE},
 368     {"set",setCommand,3,REDIS_CMD_BULK},
 369     {"setnx",setnxCommand,3,REDIS_CMD_BULK},
 370     {"del",delCommand,2,REDIS_CMD_INLINE},
 371     {"exists",existsCommand,2,REDIS_CMD_INLINE},
 372     {"incr",incrCommand,2,REDIS_CMD_INLINE},
 373     {"decr",decrCommand,2,REDIS_CMD_INLINE},
 374     {"mget",mgetCommand,-2,REDIS_CMD_INLINE},
 375     {"rpush",rpushCommand,3,REDIS_CMD_BULK},
 376     {"lpush",lpushCommand,3,REDIS_CMD_BULK},
 377     {"rpop",rpopCommand,2,REDIS_CMD_INLINE},
 378     {"lpop",lpopCommand,2,REDIS_CMD_INLINE},
 379     {"llen",llenCommand,2,REDIS_CMD_INLINE},
 380     {"lindex",lindexCommand,3,REDIS_CMD_INLINE},
 381     {"lset",lsetCommand,4,REDIS_CMD_BULK},
 382     {"lrange",lrangeCommand,4,REDIS_CMD_INLINE},
 383     {"ltrim",ltrimCommand,4,REDIS_CMD_INLINE},
 384     {"lrem",lremCommand,4,REDIS_CMD_BULK},
 385     {"sadd",saddCommand,3,REDIS_CMD_BULK},
 386     {"srem",sremCommand,3,REDIS_CMD_BULK},
 387     {"smove",smoveCommand,4,REDIS_CMD_BULK},
 388     {"sismember",sismemberCommand,3,REDIS_CMD_BULK},
 389     {"scard",scardCommand,2,REDIS_CMD_INLINE},
 390     {"sinter",sinterCommand,-2,REDIS_CMD_INLINE},
 391     {"sinterstore",sinterstoreCommand,-3,REDIS_CMD_INLINE},
 392     {"sunion",sunionCommand,-2,REDIS_CMD_INLINE},
 393     {"sunionstore",sunionstoreCommand,-3,REDIS_CMD_INLINE},
 394     {"smembers",sinterCommand,2,REDIS_CMD_INLINE},
 395     {"incrby",incrbyCommand,3,REDIS_CMD_INLINE},
 396     {"decrby",decrbyCommand,3,REDIS_CMD_INLINE},
 397     {"getset",getSetCommand,3,REDIS_CMD_BULK},
 398     {"randomkey",randomkeyCommand,1,REDIS_CMD_INLINE},
 399     {"select",selectCommand,2,REDIS_CMD_INLINE},
 400     {"move",moveCommand,3,REDIS_CMD_INLINE},
 401     {"rename",renameCommand,3,REDIS_CMD_INLINE},
 402     {"renamenx",renamenxCommand,3,REDIS_CMD_INLINE},
 403     {"keys",keysCommand,2,REDIS_CMD_INLINE},
 404     {"dbsize",dbsizeCommand,1,REDIS_CMD_INLINE},
 405     {"auth",authCommand,2,REDIS_CMD_INLINE},
 406     {"ping",pingCommand,1,REDIS_CMD_INLINE},
 407     {"echo",echoCommand,2,REDIS_CMD_BULK},
 408     {"save",saveCommand,1,REDIS_CMD_INLINE},
 409     {"bgsave",bgsaveCommand,1,REDIS_CMD_INLINE},
 410     {"shutdown",shutdownCommand,1,REDIS_CMD_INLINE},
 411     {"lastsave",lastsaveCommand,1,REDIS_CMD_INLINE},
 412     {"type",typeCommand,2,REDIS_CMD_INLINE},
 413     {"sync",syncCommand,1,REDIS_CMD_INLINE},
 414     {"flushdb",flushdbCommand,1,REDIS_CMD_INLINE},
 415     {"flushall",flushallCommand,1,REDIS_CMD_INLINE},
 416     {"sort",sortCommand,-2,REDIS_CMD_INLINE},
 417     {"info",infoCommand,1,REDIS_CMD_INLINE},
 418     {"monitor",monitorCommand,1,REDIS_CMD_INLINE},
 419     {"expire",expireCommand,3,REDIS_CMD_INLINE},
 420     {NULL,NULL,0,0}
 421 };
 422
 423 /*============================ Utility functions ============================ */
 424
 425 /* Glob-style pattern matching. */
 426 int stringmatchlen(const char *pattern, int patternLen,
 427         const char *string, int stringLen, int nocase)
 428 {
 429     while(patternLen) {
 430         switch(pattern[0]) {
 431         case '*':
 432             while (pattern[1] == '*') {
 433                 pattern++;
 434                 patternLen--;
 435             }
 436             if (patternLen == 1)
 437                 return 1; /* match */
 438             while(stringLen) {
 439                 if (stringmatchlen(pattern+1, patternLen-1,
 440                             string, stringLen, nocase))
 441                     return 1; /* match */
 442                 string++;
 443                 stringLen--;
 444             }
 445             return 0; /* no match */
 446             break;
 447         case '?':
 448             if (stringLen == 0)
 449                 return 0; /* no match */
 450             string++;
 451             stringLen--;
 452             break;
 453         case '[':
 454         {
 455             int not, match;
 456
 457             pattern++;
 458             patternLen--;
 459             not = pattern[0] == '^';
 460             if (not) {
 461                 pattern++;
 462                 patternLen--;
 463             }
 464             match = 0;
 465             while(1) {
 466                 if (pattern[0] == '\\') {
 467                     pattern++;
 468                     patternLen--;
 469                     if (pattern[0] == string[0])
 470                         match = 1;
 471                 } else if (pattern[0] == ']') {
 472                     break;
 473                 } else if (patternLen == 0) {
 474                     pattern--;
 475                     patternLen++;
 476                     break;
 477                 } else if (pattern[1] == '-' && patternLen >= 3) {
 478                     int start = pattern[0];
 479                     int end = pattern[2];
 480                     int c = string[0];
 481                     if (start > end) {
 482                         int t = start;
 483                         start = end;
 484                         end = t;
 485                     }
 486                     if (nocase) {
 487                         start = tolower(start);
 488                         end = tolower(end);
 489                         c = tolower(c);
 490                     }
 491                     pattern += 2;
 492                     patternLen -= 2;
 493                     if (c >= start && c <= end)
 494                         match = 1;
 495                 } else {
 496                     if (!nocase) {
 497                         if (pattern[0] == string[0])
 498                             match = 1;
 499                     } else {
 500                         if (tolower((int)pattern[0]) == tolower((int)string[0]))
 501                             match = 1;
 502                     }
 503                 }
 504                 pattern++;
 505                 patternLen--;
 506             }
 507             if (not)
 508                 match = !match;
 509             if (!match)
 510                 return 0; /* no match */
 511             string++;
 512             stringLen--;
 513             break;
 514         }
 515         case '\\':
 516             if (patternLen >= 2) {
 517                 pattern++;
 518                 patternLen--;
 519             }
 520             /* fall through */
 521         default:
 522             if (!nocase) {
 523                 if (pattern[0] != string[0])
 524                     return 0; /* no match */
 525             } else {
 526                 if (tolower((int)pattern[0]) != tolower((int)string[0]))
 527                     return 0; /* no match */
 528             }
 529             string++;
 530             stringLen--;
 531             break;
 532         }
 533         pattern++;
 534         patternLen--;
 535         if (stringLen == 0) {
 536             while(*pattern == '*') {
 537                 pattern++;
 538                 patternLen--;
 539             }
 540             break;
 541         }
 542     }
 543     if (patternLen == 0 && stringLen == 0)
 544         return 1;
 545     return 0;
 546 }
 547
 548 void redisLog(int level, const char *fmt, ...)
 549 {
 550     va_list ap;
 551     FILE *fp;
 552
 553     fp = (server.logfile == NULL) ? stdout : fopen(server.logfile,"a");
 554     if (!fp) return;
 555
 556     va_start(ap, fmt);
 557     if (level >= server.verbosity) {
 558         char *c = ".-*";
 559         fprintf(fp,"%c ",c[level]);
 560         vfprintf(fp, fmt, ap);
 561         fprintf(fp,"\n");
 562         fflush(fp);
 563     }
 564     va_end(ap);
 565
 566     if (server.logfile) fclose(fp);
 567 }
 568
 569 /*====================== Hash table type implementation  ==================== */
 570
 571 /* This is an hash table type that uses the SDS dynamic strings libary as
 572  * keys and radis objects as values (objects can hold SDS strings,
 573  * lists, sets). */
 574
 575 static int sdsDictKeyCompare(void *privdata, const void *key1,
 576         const void *key2)
 577 {
 578     int l1,l2;
 579     DICT_NOTUSED(privdata);
 580
 581     l1 = sdslen((sds)key1);
 582     l2 = sdslen((sds)key2);
 583     if (l1 != l2) return 0;
 584     return memcmp(key1, key2, l1) == 0;
 585 }
 586
 587 static void dictRedisObjectDestructor(void *privdata, void *val)
 588 {
 589     DICT_NOTUSED(privdata);
 590
 591     decrRefCount(val);
 592 }
 593
 594 static int dictSdsKeyCompare(void *privdata, const void *key1,
 595         const void *key2)
 596 {
 597     const robj *o1 = key1, *o2 = key2;
 598     return sdsDictKeyCompare(privdata,o1->ptr,o2->ptr);
 599 }
 600
 601 static unsigned int dictSdsHash(const void *key) {
 602     const robj *o = key;
 603     return dictGenHashFunction(o->ptr, sdslen((sds)o->ptr));
 604 }
 605
 606 static dictType setDictType = {
 607     dictSdsHash,               /* hash function */
 608     NULL,                      /* key dup */
 609     NULL,                      /* val dup */
 610     dictSdsKeyCompare,         /* key compare */
 611     dictRedisObjectDestructor, /* key destructor */
 612     NULL                       /* val destructor */
 613 };
 614
 615 static dictType hashDictType = {
 616     dictSdsHash,                /* hash function */
 617     NULL,                       /* key dup */
 618     NULL,                       /* val dup */
 619     dictSdsKeyCompare,          /* key compare */
 620     dictRedisObjectDestructor,  /* key destructor */
 621     dictRedisObjectDestructor   /* val destructor */
 622 };
 623
 624 /* ========================= Random utility functions ======================= */
 625
 626 /* Redis generally does not try to recover from out of memory conditions
 627  * when allocating objects or strings, it is not clear if it will be possible
 628  * to report this condition to the client since the networking layer itself
 629  * is based on heap allocation for send buffers, so we simply abort.
 630  * At least the code will be simpler to read... */
 631 static void oom(const char *msg) {
 632     fprintf(stderr, "%s: Out of memory\n",msg);
 633     fflush(stderr);
 634     sleep(1);
 635     abort();
 636 }
 637
 638 /* ====================== Redis server networking stuff ===================== */
 639 void closeTimedoutClients(void) {
 640     redisClient *c;
 641     listNode *ln;
 642     time_t now = time(NULL);
 643
 644     listRewind(server.clients);
 645     while ((ln = listYield(server.clients)) != NULL) {
 646         c = listNodeValue(ln);
 647         if (!(c->flags & REDIS_SLAVE) &&    /* no timeout for slaves */
 648              (now - c->lastinteraction > server.maxidletime)) {
 649             redisLog(REDIS_DEBUG,"Closing idle client");
 650             freeClient(c);
 651         }
 652     }
 653 }
 654
 655 /* If the percentage of used slots in the HT reaches REDIS_HT_MINFILL
 656  * we resize the hash table to save memory */
 657 void tryResizeHashTables(void) {
 658     int j;
 659
 660     for (j = 0; j < server.dbnum; j++) {
 661         long long size, used;
 662
 663         size = dictSlots(server.db[j].dict);
 664         used = dictSize(server.db[j].dict);
 665         if (size && used && size > REDIS_HT_MINSLOTS &&
 666             (used*100/size < REDIS_HT_MINFILL)) {
 667             redisLog(REDIS_NOTICE,"The hash table %d is too sparse, resize it...",j);
 668             dictResize(server.db[j].dict);
 669             redisLog(REDIS_NOTICE,"Hash table %d resized.",j);
 670         }
 671     }
 672 }
 673
 674 int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
 675     int j, loops = server.cronloops++;
 676     REDIS_NOTUSED(eventLoop);
 677     REDIS_NOTUSED(id);
 678     REDIS_NOTUSED(clientData);
 679
 680     /* Update the global state with the amount of used memory */
 681     server.usedmemory = zmalloc_used_memory();
 682
 683     /* Show some info about non-empty databases */
 684     for (j = 0; j < server.dbnum; j++) {
 685         long long size, used, vkeys;
 686
 687         size = dictSlots(server.db[j].dict);
 688         used = dictSize(server.db[j].dict);
 689         vkeys = dictSize(server.db[j].expires);
 690         if (!(loops % 5) && used > 0) {
 691             redisLog(REDIS_DEBUG,"DB %d: %d keys (%d volatile) in %d slots HT.",j,used,vkeys,size);
 692             /* dictPrintStats(server.dict); */
 693         }
 694     }
 695
 696     /* We don't want to resize the hash tables while a bacground saving
 697      * is in progress: the saving child is created using fork() that is
 698      * implemented with a copy-on-write semantic in most modern systems, so
 699      * if we resize the HT while there is the saving child at work actually
 700      * a lot of memory movements in the parent will cause a lot of pages
 701      * copied. */
 702     if (!server.bgsaveinprogress) tryResizeHashTables();
 703
 704     /* Show information about connected clients */
 705     if (!(loops % 5)) {
 706         redisLog(REDIS_DEBUG,"%d clients connected (%d slaves), %zu bytes in use",
 707             listLength(server.clients)-listLength(server.slaves),
 708             listLength(server.slaves),
 709             server.usedmemory,
 710             dictSize(server.sharingpool));
 711     }
 712
 713     /* Close connections of timedout clients */
 714     if (!(loops % 10))
 715         closeTimedoutClients();
 716
 717     /* Check if a background saving in progress terminated */
 718     if (server.bgsaveinprogress) {
 719         int statloc;
 720         /* XXX: TODO handle the case of the saving child killed */
 721         if (wait4(-1,&statloc,WNOHANG,NULL)) {
 722             int exitcode = WEXITSTATUS(statloc);
 723             if (exitcode == 0) {
 724                 redisLog(REDIS_NOTICE,
 725                     "Background saving terminated with success");
 726                 server.dirty = 0;
 727                 server.lastsave = time(NULL);
 728             } else {
 729                 redisLog(REDIS_WARNING,
 730                     "Background saving error");
 731             }
 732             server.bgsaveinprogress = 0;
 733             updateSalvesWaitingBgsave(exitcode == 0 ? REDIS_OK : REDIS_ERR);
 734         }
 735     } else {
 736         /* If there is not a background saving in progress check if
 737          * we have to save now */
 738          time_t now = time(NULL);
 739          for (j = 0; j < server.saveparamslen; j++) {
 740             struct saveparam *sp = server.saveparams+j;
 741
 742             if (server.dirty >= sp->changes &&
 743                 now-server.lastsave > sp->seconds) {
 744                 redisLog(REDIS_NOTICE,"%d changes in %d seconds. Saving...",
 745                     sp->changes, sp->seconds);
 746                 rdbSaveBackground(server.dbfilename);
 747                 break;
 748             }
 749          }
 750     }
 751
 752     /* Try to expire a few timed out keys */
 753     for (j = 0; j < server.dbnum; j++) {
 754         redisDb *db = server.db+j;
 755         int num = dictSize(db->expires);
 756
 757         if (num) {
 758             time_t now = time(NULL);
 759
 760             if (num > REDIS_EXPIRELOOKUPS_PER_CRON)
 761                 num = REDIS_EXPIRELOOKUPS_PER_CRON;
 762             while (num--) {
 763                 dictEntry *de;
 764                 time_t t;
 765
 766                 if ((de = dictGetRandomKey(db->expires)) == NULL) break;
 767                 t = (time_t) dictGetEntryVal(de);
 768                 if (now > t) {
 769                     deleteKey(db,dictGetEntryKey(de));
 770                 }
 771             }
 772         }
 773     }
 774
 775     /* Check if we should connect to a MASTER */
 776     if (server.replstate == REDIS_REPL_CONNECT) {
 777         redisLog(REDIS_NOTICE,"Connecting to MASTER...");
 778         if (syncWithMaster() == REDIS_OK) {
 779             redisLog(REDIS_NOTICE,"MASTER <-> SLAVE sync succeeded");
 780         }
 781     }
 782     return 1000;
 783 }
 784
 785 static void createSharedObjects(void) {
 786     shared.crlf = createObject(REDIS_STRING,sdsnew("\r\n"));
 787     shared.ok = createObject(REDIS_STRING,sdsnew("+OK\r\n"));
 788     shared.err = createObject(REDIS_STRING,sdsnew("-ERR\r\n"));
 789     shared.emptybulk = createObject(REDIS_STRING,sdsnew("$0\r\n\r\n"));
 790     shared.czero = createObject(REDIS_STRING,sdsnew(":0\r\n"));
 791     shared.cone = createObject(REDIS_STRING,sdsnew(":1\r\n"));
 792     shared.nullbulk = createObject(REDIS_STRING,sdsnew("$-1\r\n"));
 793     shared.nullmultibulk = createObject(REDIS_STRING,sdsnew("*-1\r\n"));
 794     shared.emptymultibulk = createObject(REDIS_STRING,sdsnew("*0\r\n"));
 795     /* no such key */
 796     shared.pong = createObject(REDIS_STRING,sdsnew("+PONG\r\n"));
 797     shared.wrongtypeerr = createObject(REDIS_STRING,sdsnew(
 798         "-ERR Operation against a key holding the wrong kind of value\r\n"));
 799     shared.nokeyerr = createObject(REDIS_STRING,sdsnew(
 800         "-ERR no such key\r\n"));
 801     shared.syntaxerr = createObject(REDIS_STRING,sdsnew(
 802         "-ERR syntax error\r\n"));
 803     shared.sameobjecterr = createObject(REDIS_STRING,sdsnew(
 804         "-ERR source and destination objects are the same\r\n"));
 805     shared.outofrangeerr = createObject(REDIS_STRING,sdsnew(
 806         "-ERR index out of range\r\n"));
 807     shared.space = createObject(REDIS_STRING,sdsnew(" "));
 808     shared.colon = createObject(REDIS_STRING,sdsnew(":"));
 809     shared.plus = createObject(REDIS_STRING,sdsnew("+"));
 810     shared.select0 = createStringObject("select 0\r\n",10);
 811     shared.select1 = createStringObject("select 1\r\n",10);
 812     shared.select2 = createStringObject("select 2\r\n",10);
 813     shared.select3 = createStringObject("select 3\r\n",10);
 814     shared.select4 = createStringObject("select 4\r\n",10);
 815     shared.select5 = createStringObject("select 5\r\n",10);
 816     shared.select6 = createStringObject("select 6\r\n",10);
 817     shared.select7 = createStringObject("select 7\r\n",10);
 818     shared.select8 = createStringObject("select 8\r\n",10);
 819     shared.select9 = createStringObject("select 9\r\n",10);
 820 }
 821
 822 static void appendServerSaveParams(time_t seconds, int changes) {
 823     server.saveparams = zrealloc(server.saveparams,sizeof(struct saveparam)*(server.saveparamslen+1));
 824     if (server.saveparams == NULL) oom("appendServerSaveParams");
 825     server.saveparams[server.saveparamslen].seconds = seconds;
 826     server.saveparams[server.saveparamslen].changes = changes;
 827     server.saveparamslen++;
 828 }
 829
 830 static void ResetServerSaveParams() {
 831     zfree(server.saveparams);
 832     server.saveparams = NULL;
 833     server.saveparamslen = 0;
 834 }
 835
 836 static void initServerConfig() {
 837     server.dbnum = REDIS_DEFAULT_DBNUM;
 838     server.port = REDIS_SERVERPORT;
 839     server.verbosity = REDIS_DEBUG;
 840     server.maxidletime = REDIS_MAXIDLETIME;
 841     server.saveparams = NULL;
 842     server.logfile = NULL; /* NULL = log on standard output */
 843     server.bindaddr = NULL;
 844     server.glueoutputbuf = 1;
 845     server.daemonize = 0;
 846     server.pidfile = "/var/run/redis.pid";
 847     server.dbfilename = "dump.rdb";
 848     server.requirepass = NULL;
 849     server.shareobjects = 0;
 850     ResetServerSaveParams();
 851
 852     appendServerSaveParams(60*60,1);  /* save after 1 hour and 1 change */
 853     appendServerSaveParams(300,100);  /* save after 5 minutes and 100 changes */
 854     appendServerSaveParams(60,10000); /* save after 1 minute and 10000 changes */
 855     /* Replication related */
 856     server.isslave = 0;
 857     server.masterhost = NULL;
 858     server.masterport = 6379;
 859     server.master = NULL;
 860     server.replstate = REDIS_REPL_NONE;
 861 }
 862
 863 static void initServer() {
 864     int j;
 865
 866     signal(SIGHUP, SIG_IGN);
 867     signal(SIGPIPE, SIG_IGN);
 868
 869     server.clients = listCreate();
 870     server.slaves = listCreate();
 871     server.monitors = listCreate();
 872     server.objfreelist = listCreate();
 873     createSharedObjects();
 874     server.el = aeCreateEventLoop();
 875     server.db = zmalloc(sizeof(redisDb)*server.dbnum);
 876     server.sharingpool = dictCreate(&setDictType,NULL);
 877     server.sharingpoolsize = 1024;
 878     if (!server.db || !server.clients || !server.slaves || !server.monitors || !server.el || !server.objfreelist)
 879         oom("server initialization"); /* Fatal OOM */
 880     server.fd = anetTcpServer(server.neterr, server.port, server.bindaddr);
 881     if (server.fd == -1) {
 882         redisLog(REDIS_WARNING, "Opening TCP port: %s", server.neterr);
 883         exit(1);
 884     }
 885     for (j = 0; j < server.dbnum; j++) {
 886         server.db[j].dict = dictCreate(&hashDictType,NULL);
 887         server.db[j].expires = dictCreate(&setDictType,NULL);
 888         server.db[j].id = j;
 889     }
 890     server.cronloops = 0;
 891     server.bgsaveinprogress = 0;
 892     server.lastsave = time(NULL);
 893     server.dirty = 0;
 894     server.usedmemory = 0;
 895     server.stat_numcommands = 0;
 896     server.stat_numconnections = 0;
 897     server.stat_starttime = time(NULL);
 898     aeCreateTimeEvent(server.el, 1000, serverCron, NULL, NULL);
 899 }
 900
 901 /* Empty the whole database */
 902 static long long emptyDb() {
 903     int j;
 904     long long removed = 0;
 905
 906     for (j = 0; j < server.dbnum; j++) {
 907         removed += dictSize(server.db[j].dict);
 908         dictEmpty(server.db[j].dict);
 909         dictEmpty(server.db[j].expires);
 910     }
 911     return removed;
 912 }
 913
 914 static int yesnotoi(char *s) {
 915     if (!strcasecmp(s,"yes")) return 1;
 916     else if (!strcasecmp(s,"no")) return 0;
 917     else return -1;
 918 }
 919
 920 /* I agree, this is a very rudimental way to load a configuration...
 921    will improve later if the config gets more complex */
 922 static void loadServerConfig(char *filename) {
 923     FILE *fp = fopen(filename,"r");
 924     char buf[REDIS_CONFIGLINE_MAX+1], *err = NULL;
 925     int linenum = 0;
 926     sds line = NULL;
 927
 928     if (!fp) {
 929         redisLog(REDIS_WARNING,"Fatal error, can't open config file");
 930         exit(1);
 931     }
 932     while(fgets(buf,REDIS_CONFIGLINE_MAX+1,fp) != NULL) {
 933         sds *argv;
 934         int argc, j;
 935
 936         linenum++;
 937         line = sdsnew(buf);
 938         line = sdstrim(line," \t\r\n");
 939
 940         /* Skip comments and blank lines*/
 941         if (line[0] == '#' || line[0] == '\0') {
 942             sdsfree(line);
 943             continue;
 944         }
 945
 946         /* Split into arguments */
 947         argv = sdssplitlen(line,sdslen(line)," ",1,&argc);
 948         sdstolower(argv[0]);
 949
 950         /* Execute config directives */
 951         if (!strcasecmp(argv[0],"timeout") && argc == 2) {
 952             server.maxidletime = atoi(argv[1]);
 953             if (server.maxidletime < 1) {
 954                 err = "Invalid timeout value"; goto loaderr;
 955             }
 956         } else if (!strcasecmp(argv[0],"port") && argc == 2) {
 957             server.port = atoi(argv[1]);
 958             if (server.port < 1 || server.port > 65535) {
 959                 err = "Invalid port"; goto loaderr;
 960             }
 961         } else if (!strcasecmp(argv[0],"bind") && argc == 2) {
 962             server.bindaddr = zstrdup(argv[1]);
 963         } else if (!strcasecmp(argv[0],"save") && argc == 3) {
 964             int seconds = atoi(argv[1]);
 965             int changes = atoi(argv[2]);
 966             if (seconds < 1 || changes < 0) {
 967                 err = "Invalid save parameters"; goto loaderr;
 968             }
 969             appendServerSaveParams(seconds,changes);
 970         } else if (!strcasecmp(argv[0],"dir") && argc == 2) {
 971             if (chdir(argv[1]) == -1) {
 972                 redisLog(REDIS_WARNING,"Can't chdir to '%s': %s",
 973                     argv[1], strerror(errno));
 974                 exit(1);
 975             }
 976         } else if (!strcasecmp(argv[0],"loglevel") && argc == 2) {
 977             if (!strcasecmp(argv[1],"debug")) server.verbosity = REDIS_DEBUG;
 978             else if (!strcasecmp(argv[1],"notice")) server.verbosity = REDIS_NOTICE;
 979             else if (!strcasecmp(argv[1],"warning")) server.verbosity = REDIS_WARNING;
 980             else {
 981                 err = "Invalid log level. Must be one of debug, notice, warning";
 982                 goto loaderr;
 983             }
 984         } else if (!strcasecmp(argv[0],"logfile") && argc == 2) {
 985             FILE *fp;
 986
 987             server.logfile = zstrdup(argv[1]);
 988             if (!strcasecmp(server.logfile,"stdout")) {
 989                 zfree(server.logfile);
 990                 server.logfile = NULL;
 991             }
 992             if (server.logfile) {
 993                 /* Test if we are able to open the file. The server will not
 994                  * be able to abort just for this problem later... */
 995                 fp = fopen(server.logfile,"a");
 996                 if (fp == NULL) {
 997                     err = sdscatprintf(sdsempty(),
 998                         "Can't open the log file: %s", strerror(errno));
 999                     goto loaderr;
1000                 }
1001                 fclose(fp);
1002             }
1003         } else if (!strcasecmp(argv[0],"databases") && argc == 2) {
1004             server.dbnum = atoi(argv[1]);
1005             if (server.dbnum < 1) {
1006                 err = "Invalid number of databases"; goto loaderr;
1007             }
1008         } else if (!strcasecmp(argv[0],"slaveof") && argc == 3) {
1009             server.masterhost = sdsnew(argv[1]);
1010             server.masterport = atoi(argv[2]);
1011             server.replstate = REDIS_REPL_CONNECT;
1012         } else if (!strcasecmp(argv[0],"glueoutputbuf") && argc == 2) {
1013             if ((server.glueoutputbuf = yesnotoi(argv[1])) == -1) {
1014                 err = "argument must be 'yes' or 'no'"; goto loaderr;
1015             }
1016         } else if (!strcasecmp(argv[0],"shareobjects") && argc == 2) {
1017             if ((server.shareobjects = yesnotoi(argv[1])) == -1) {
1018                 err = "argument must be 'yes' or 'no'"; goto loaderr;
1019             }
1020         } else if (!strcasecmp(argv[0],"daemonize") && argc == 2) {
1021             if ((server.daemonize = yesnotoi(argv[1])) == -1) {
1022                 err = "argument must be 'yes' or 'no'"; goto loaderr;
1023             }
1024         } else if (!strcasecmp(argv[0],"requirepass") && argc == 2) {
1025           server.requirepass = zstrdup(argv[1]);
1026         } else if (!strcasecmp(argv[0],"pidfile") && argc == 2) {
1027           server.pidfile = zstrdup(argv[1]);
1028         } else if (!strcasecmp(argv[0],"dbfilename") && argc == 2) {
1029           server.dbfilename = zstrdup(argv[1]);
1030         } else {
1031             err = "Bad directive or wrong number of arguments"; goto loaderr;
1032         }
1033         for (j = 0; j < argc; j++)
1034             sdsfree(argv[j]);
1035         zfree(argv);
1036         sdsfree(line);
1037     }
1038     fclose(fp);
1039     return;
1040
1041 loaderr:
1042     fprintf(stderr, "\n*** FATAL CONFIG FILE ERROR ***\n");
1043     fprintf(stderr, "Reading the configuration file, at line %d\n", linenum);
1044     fprintf(stderr, ">>> '%s'\n", line);
1045     fprintf(stderr, "%s\n", err);
1046     exit(1);
1047 }
1048
1049 static void freeClientArgv(redisClient *c) {
1050     int j;
1051
1052     for (j = 0; j < c->argc; j++)
1053         decrRefCount(c->argv[j]);
1054     c->argc = 0;
1055 }
1056
1057 static void freeClient(redisClient *c) {
1058     listNode *ln;
1059
1060     aeDeleteFileEvent(server.el,c->fd,AE_READABLE);
1061     aeDeleteFileEvent(server.el,c->fd,AE_WRITABLE);
1062     sdsfree(c->querybuf);
1063     listRelease(c->reply);
1064     freeClientArgv(c);
1065     close(c->fd);
1066     ln = listSearchKey(server.clients,c);
1067     assert(ln != NULL);
1068     listDelNode(server.clients,ln);
1069     if (c->flags & REDIS_SLAVE) {
1070         if (c->replstate == REDIS_REPL_SEND_BULK && c->repldbfd != -1)
1071             close(c->repldbfd);
1072         list *l = (c->flags & REDIS_MONITOR) ? server.monitors : server.slaves;
1073         ln = listSearchKey(l,c);
1074         assert(ln != NULL);
1075         listDelNode(l,ln);
1076     }
1077     if (c->flags & REDIS_MASTER) {
1078         server.master = NULL;
1079         server.replstate = REDIS_REPL_CONNECT;
1080     }
1081     zfree(c->argv);
1082     zfree(c);
1083 }
1084
1085 static void glueReplyBuffersIfNeeded(redisClient *c) {
1086     int totlen = 0;
1087     listNode *ln;
1088     robj *o;
1089
1090     listRewind(c->reply);
1091     while((ln = listYield(c->reply))) {
1092         o = ln->value;
1093         totlen += sdslen(o->ptr);
1094         /* This optimization makes more sense if we don't have to copy
1095          * too much data */
1096         if (totlen > 1024) return;
1097     }
1098     if (totlen > 0) {
1099         char buf[1024];
1100         int copylen = 0;
1101
1102         listRewind(c->reply);
1103         while((ln = listYield(c->reply))) {
1104             o = ln->value;
1105             memcpy(buf+copylen,o->ptr,sdslen(o->ptr));
1106             copylen += sdslen(o->ptr);
1107             listDelNode(c->reply,ln);
1108         }
1109         /* Now the output buffer is empty, add the new single element */
1110         addReplySds(c,sdsnewlen(buf,totlen));
1111     }
1112 }
1113
1114 static void sendReplyToClient(aeEventLoop *el, int fd, void *privdata, int mask) {
1115     redisClient *c = privdata;
1116     int nwritten = 0, totwritten = 0, objlen;
1117     robj *o;
1118     REDIS_NOTUSED(el);
1119     REDIS_NOTUSED(mask);
1120
1121     if (server.glueoutputbuf && listLength(c->reply) > 1)
1122         glueReplyBuffersIfNeeded(c);
1123     while(listLength(c->reply)) {
1124         o = listNodeValue(listFirst(c->reply));
1125         objlen = sdslen(o->ptr);
1126
1127         if (objlen == 0) {
1128             listDelNode(c->reply,listFirst(c->reply));
1129             continue;
1130         }
1131
1132         if (c->flags & REDIS_MASTER) {
1133             nwritten = objlen - c->sentlen;
1134         } else {
1135             nwritten = write(fd, ((char*)o->ptr)+c->sentlen, objlen - c->sentlen);
1136             if (nwritten <= 0) break;
1137         }
1138         c->sentlen += nwritten;
1139         totwritten += nwritten;
1140         /* If we fully sent the object on head go to the next one */
1141         if (c->sentlen == objlen) {
1142             listDelNode(c->reply,listFirst(c->reply));
1143             c->sentlen = 0;
1144         }
1145     }
1146     if (nwritten == -1) {
1147         if (errno == EAGAIN) {
1148             nwritten = 0;
1149         } else {
1150             redisLog(REDIS_DEBUG,
1151                 "Error writing to client: %s", strerror(errno));
1152             freeClient(c);
1153             return;
1154         }
1155     }
1156     if (totwritten > 0) c->lastinteraction = time(NULL);
1157     if (listLength(c->reply) == 0) {
1158         c->sentlen = 0;
1159         aeDeleteFileEvent(server.el,c->fd,AE_WRITABLE);
1160     }
1161 }
1162
1163 static struct redisCommand *lookupCommand(char *name) {
1164     int j = 0;
1165     while(cmdTable[j].name != NULL) {
1166         if (!strcasecmp(name,cmdTable[j].name)) return &cmdTable[j];
1167         j++;
1168     }
1169     return NULL;
1170 }
1171
1172 /* resetClient prepare the client to process the next command */
1173 static void resetClient(redisClient *c) {
1174     freeClientArgv(c);
1175     c->bulklen = -1;
1176 }
1177
1178 /* If this function gets called we already read a whole
1179  * command, argments are in the client argv/argc fields.
1180  * processCommand() execute the command or prepare the
1181  * server for a bulk read from the client.
1182  *
1183  * If 1 is returned the client is still alive and valid and
1184  * and other operations can be performed by the caller. Otherwise
1185  * if 0 is returned the client was destroied (i.e. after QUIT). */
1186 static int processCommand(redisClient *c) {
1187     struct redisCommand *cmd;
1188     long long dirty;
1189
1190     /* The QUIT command is handled as a special case. Normal command
1191      * procs are unable to close the client connection safely */
1192     if (!strcasecmp(c->argv[0]->ptr,"quit")) {
1193         freeClient(c);
1194         return 0;
1195     }
1196     cmd = lookupCommand(c->argv[0]->ptr);
1197     if (!cmd) {
1198         addReplySds(c,sdsnew("-ERR unknown command\r\n"));
1199         resetClient(c);
1200         return 1;
1201     } else if ((cmd->arity > 0 && cmd->arity != c->argc) ||
1202                (c->argc < -cmd->arity)) {
1203         addReplySds(c,sdsnew("-ERR wrong number of arguments\r\n"));
1204         resetClient(c);
1205         return 1;
1206     } else if (cmd->flags & REDIS_CMD_BULK && c->bulklen == -1) {
1207         int bulklen = atoi(c->argv[c->argc-1]->ptr);
1208
1209         decrRefCount(c->argv[c->argc-1]);
1210         if (bulklen < 0 || bulklen > 1024*1024*1024) {
1211             c->argc--;
1212             addReplySds(c,sdsnew("-ERR invalid bulk write count\r\n"));
1213             resetClient(c);
1214             return 1;
1215         }
1216         c->argc--;
1217         c->bulklen = bulklen+2; /* add two bytes for CR+LF */
1218         /* It is possible that the bulk read is already in the
1219          * buffer. Check this condition and handle it accordingly */
1220         if ((signed)sdslen(c->querybuf) >= c->bulklen) {
1221             c->argv[c->argc] = createStringObject(c->querybuf,c->bulklen-2);
1222             c->argc++;
1223             c->querybuf = sdsrange(c->querybuf,c->bulklen,-1);
1224         } else {
1225             return 1;
1226         }
1227     }
1228     /* Let's try to share objects on the command arguments vector */
1229     if (server.shareobjects) {
1230         int j;
1231         for(j = 1; j < c->argc; j++)
1232             c->argv[j] = tryObjectSharing(c->argv[j]);
1233     }
1234     /* Check if the user is authenticated */
1235     if (server.requirepass && !c->authenticated && cmd->proc != authCommand) {
1236         addReplySds(c,sdsnew("-ERR operation not permitted\r\n"));
1237         resetClient(c);
1238         return 1;
1239     }
1240
1241     /* Exec the command */
1242     dirty = server.dirty;
1243     cmd->proc(c);
1244     if (server.dirty-dirty != 0 && listLength(server.slaves))
1245         replicationFeedSlaves(server.slaves,cmd,c->db->id,c->argv,c->argc);
1246     if (listLength(server.monitors))
1247         replicationFeedSlaves(server.monitors,cmd,c->db->id,c->argv,c->argc);
1248     server.stat_numcommands++;
1249
1250     /* Prepare the client for the next command */
1251     if (c->flags & REDIS_CLOSE) {
1252         freeClient(c);
1253         return 0;
1254     }
1255     resetClient(c);
1256     return 1;
1257 }
1258
1259 static void replicationFeedSlaves(list *slaves, struct redisCommand *cmd, int dictid, robj **argv, int argc) {
1260     listNode *ln;
1261     int outc = 0, j;
1262     robj **outv;
1263     /* (args*2)+1 is enough room for args, spaces, newlines */
1264     robj *static_outv[REDIS_STATIC_ARGS*2+1];
1265
1266     if (argc <= REDIS_STATIC_ARGS) {
1267         outv = static_outv;
1268     } else {
1269         outv = zmalloc(sizeof(robj*)*(argc*2+1));
1270         if (!outv) oom("replicationFeedSlaves");
1271     }
1272
1273     for (j = 0; j < argc; j++) {
1274         if (j != 0) outv[outc++] = shared.space;
1275         if ((cmd->flags & REDIS_CMD_BULK) && j == argc-1) {
1276             robj *lenobj;
1277
1278             lenobj = createObject(REDIS_STRING,
1279                 sdscatprintf(sdsempty(),"%d\r\n",sdslen(argv[j]->ptr)));
1280             lenobj->refcount = 0;
1281             outv[outc++] = lenobj;
1282         }
1283         outv[outc++] = argv[j];
1284     }
1285     outv[outc++] = shared.crlf;
1286
1287     /* Increment all the refcounts at start and decrement at end in order to
1288      * be sure to free objects if there is no slave in a replication state
1289      * able to be feed with commands */
1290     for (j = 0; j < outc; j++) incrRefCount(outv[j]);
1291     listRewind(slaves);
1292     while((ln = listYield(slaves))) {
1293         redisClient *slave = ln->value;
1294
1295         /* Don't feed slaves that are still waiting for BGSAVE to start */
1296         if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_START) continue;
1297
1298         /* Feed all the other slaves, MONITORs and so on */
1299         if (slave->slaveseldb != dictid) {
1300             robj *selectcmd;
1301
1302             switch(dictid) {
1303             case 0: selectcmd = shared.select0; break;
1304             case 1: selectcmd = shared.select1; break;
1305             case 2: selectcmd = shared.select2; break;
1306             case 3: selectcmd = shared.select3; break;
1307             case 4: selectcmd = shared.select4; break;
1308             case 5: selectcmd = shared.select5; break;
1309             case 6: selectcmd = shared.select6; break;
1310             case 7: selectcmd = shared.select7; break;
1311             case 8: selectcmd = shared.select8; break;
1312             case 9: selectcmd = shared.select9; break;
1313             default:
1314                 selectcmd = createObject(REDIS_STRING,
1315                     sdscatprintf(sdsempty(),"select %d\r\n",dictid));
1316                 selectcmd->refcount = 0;
1317                 break;
1318             }
1319             addReply(slave,selectcmd);
1320             slave->slaveseldb = dictid;
1321         }
1322         for (j = 0; j < outc; j++) addReply(slave,outv[j]);
1323     }
1324     for (j = 0; j < outc; j++) decrRefCount(outv[j]);
1325     if (outv != static_outv) zfree(outv);
1326 }
1327
1328 static void readQueryFromClient(aeEventLoop *el, int fd, void *privdata, int mask) {
1329     redisClient *c = (redisClient*) privdata;
1330     char buf[REDIS_IOBUF_LEN];
1331     int nread;
1332     REDIS_NOTUSED(el);
1333     REDIS_NOTUSED(mask);
1334
1335     nread = read(fd, buf, REDIS_IOBUF_LEN);
1336     if (nread == -1) {
1337         if (errno == EAGAIN) {
1338             nread = 0;
1339         } else {
1340             redisLog(REDIS_DEBUG, "Reading from client: %s",strerror(errno));
1341             freeClient(c);
1342             return;
1343         }
1344     } else if (nread == 0) {
1345         redisLog(REDIS_DEBUG, "Client closed connection");
1346         freeClient(c);
1347         return;
1348     }
1349     if (nread) {
1350         c->querybuf = sdscatlen(c->querybuf, buf, nread);
1351         c->lastinteraction = time(NULL);
1352     } else {
1353         return;
1354     }
1355
1356 again:
1357     if (c->bulklen == -1) {
1358         /* Read the first line of the query */
1359         char *p = strchr(c->querybuf,'\n');
1360         size_t querylen;
1361         if (p) {
1362             sds query, *argv;
1363             int argc, j;
1364
1365             query = c->querybuf;
1366             c->querybuf = sdsempty();
1367             querylen = 1+(p-(query));
1368             if (sdslen(query) > querylen) {
1369                 /* leave data after the first line of the query in the buffer */
1370                 c->querybuf = sdscatlen(c->querybuf,query+querylen,sdslen(query)-querylen);
1371             }
1372             *p = '\0'; /* remove "\n" */
1373             if (*(p-1) == '\r') *(p-1) = '\0'; /* and "\r" if any */
1374             sdsupdatelen(query);
1375
1376             /* Now we can split the query in arguments */
1377             if (sdslen(query) == 0) {
1378                 /* Ignore empty query */
1379                 sdsfree(query);
1380                 return;
1381             }
1382             argv = sdssplitlen(query,sdslen(query)," ",1,&argc);
1383             if (argv == NULL) oom("sdssplitlen");
1384             sdsfree(query);
1385
1386             if (c->argv) zfree(c->argv);
1387             c->argv = zmalloc(sizeof(robj*)*argc);
1388             if (c->argv == NULL) oom("allocating arguments list for client");
1389
1390             for (j = 0; j < argc; j++) {
1391                 if (sdslen(argv[j])) {
1392                     c->argv[c->argc] = createObject(REDIS_STRING,argv[j]);
1393                     c->argc++;
1394                 } else {
1395                     sdsfree(argv[j]);
1396                 }
1397             }
1398             zfree(argv);
1399             /* Execute the command. If the client is still valid
1400              * after processCommand() return and there is something
1401              * on the query buffer try to process the next command. */
1402             if (processCommand(c) && sdslen(c->querybuf)) goto again;
1403             return;
1404         } else if (sdslen(c->querybuf) >= 1024) {
1405             redisLog(REDIS_DEBUG, "Client protocol error");
1406             freeClient(c);
1407             return;
1408         }
1409     } else {
1410         /* Bulk read handling. Note that if we are at this point
1411            the client already sent a command terminated with a newline,
1412            we are reading the bulk data that is actually the last
1413            argument of the command. */
1414         int qbl = sdslen(c->querybuf);
1415
1416         if (c->bulklen <= qbl) {
1417             /* Copy everything but the final CRLF as final argument */
1418             c->argv[c->argc] = createStringObject(c->querybuf,c->bulklen-2);
1419             c->argc++;
1420             c->querybuf = sdsrange(c->querybuf,c->bulklen,-1);
1421             processCommand(c);
1422             return;
1423         }
1424     }
1425 }
1426
1427 static int selectDb(redisClient *c, int id) {
1428     if (id < 0 || id >= server.dbnum)
1429         return REDIS_ERR;
1430     c->db = &server.db[id];
1431     return REDIS_OK;
1432 }
1433
1434 static void *dupClientReplyValue(void *o) {
1435     incrRefCount((robj*)o);
1436     return 0;
1437 }
1438
1439 static redisClient *createClient(int fd) {
1440     redisClient *c = zmalloc(sizeof(*c));
1441
1442     anetNonBlock(NULL,fd);
1443     anetTcpNoDelay(NULL,fd);
1444     if (!c) return NULL;
1445     selectDb(c,0);
1446     c->fd = fd;
1447     c->querybuf = sdsempty();
1448     c->argc = 0;
1449     c->argv = NULL;
1450     c->bulklen = -1;
1451     c->sentlen = 0;
1452     c->flags = 0;
1453     c->lastinteraction = time(NULL);
1454     c->authenticated = 0;
1455     c->replstate = REDIS_REPL_NONE;
1456     if ((c->reply = listCreate()) == NULL) oom("listCreate");
1457     listSetFreeMethod(c->reply,decrRefCount);
1458     listSetDupMethod(c->reply,dupClientReplyValue);
1459     if (aeCreateFileEvent(server.el, c->fd, AE_READABLE,
1460         readQueryFromClient, c, NULL) == AE_ERR) {
1461         freeClient(c);
1462         return NULL;
1463     }
1464     if (!listAddNodeTail(server.clients,c)) oom("listAddNodeTail");
1465     return c;
1466 }
1467
1468 static void addReply(redisClient *c, robj *obj) {
1469     if (listLength(c->reply) == 0 &&
1470         (c->replstate == REDIS_REPL_NONE ||
1471          c->replstate == REDIS_REPL_ONLINE) &&
1472         aeCreateFileEvent(server.el, c->fd, AE_WRITABLE,
1473         sendReplyToClient, c, NULL) == AE_ERR) return;
1474     if (!listAddNodeTail(c->reply,obj)) oom("listAddNodeTail");
1475     incrRefCount(obj);
1476 }
1477
1478 static void addReplySds(redisClient *c, sds s) {
1479     robj *o = createObject(REDIS_STRING,s);
1480     addReply(c,o);
1481     decrRefCount(o);
1482 }
1483
1484 static void acceptHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
1485     int cport, cfd;
1486     char cip[128];
1487     REDIS_NOTUSED(el);
1488     REDIS_NOTUSED(mask);
1489     REDIS_NOTUSED(privdata);
1490
1491     cfd = anetAccept(server.neterr, fd, cip, &cport);
1492     if (cfd == AE_ERR) {
1493         redisLog(REDIS_DEBUG,"Accepting client connection: %s", server.neterr);
1494         return;
1495     }
1496     redisLog(REDIS_DEBUG,"Accepted %s:%d", cip, cport);
1497     if (createClient(cfd) == NULL) {
1498         redisLog(REDIS_WARNING,"Error allocating resoures for the client");
1499         close(cfd); /* May be already closed, just ingore errors */
1500         return;
1501     }
1502     server.stat_numconnections++;
1503 }
1504
1505 /* ======================= Redis objects implementation ===================== */
1506
1507 static robj *createObject(int type, void *ptr) {
1508     robj *o;
1509
1510     if (listLength(server.objfreelist)) {
1511         listNode *head = listFirst(server.objfreelist);
1512         o = listNodeValue(head);
1513         listDelNode(server.objfreelist,head);
1514     } else {
1515         o = zmalloc(sizeof(*o));
1516     }
1517     if (!o) oom("createObject");
1518     o->type = type;
1519     o->ptr = ptr;
1520     o->refcount = 1;
1521     return o;
1522 }
1523
1524 static robj *createStringObject(char *ptr, size_t len) {
1525     return createObject(REDIS_STRING,sdsnewlen(ptr,len));
1526 }
1527
1528 static robj *createListObject(void) {
1529     list *l = listCreate();
1530
1531     if (!l) oom("listCreate");
1532     listSetFreeMethod(l,decrRefCount);
1533     return createObject(REDIS_LIST,l);
1534 }
1535
1536 static robj *createSetObject(void) {
1537     dict *d = dictCreate(&setDictType,NULL);
1538     if (!d) oom("dictCreate");
1539     return createObject(REDIS_SET,d);
1540 }
1541
1542 static void freeStringObject(robj *o) {
1543     sdsfree(o->ptr);
1544 }
1545
1546 static void freeListObject(robj *o) {
1547     listRelease((list*) o->ptr);
1548 }
1549
1550 static void freeSetObject(robj *o) {
1551     dictRelease((dict*) o->ptr);
1552 }
1553
1554 static void freeHashObject(robj *o) {
1555     dictRelease((dict*) o->ptr);
1556 }
1557
1558 static void incrRefCount(robj *o) {
1559     o->refcount++;
1560 #ifdef DEBUG_REFCOUNT
1561     if (o->type == REDIS_STRING)
1562         printf("Increment '%s'(%p), now is: %d\n",o->ptr,o,o->refcount);
1563 #endif
1564 }
1565
1566 static void decrRefCount(void *obj) {
1567     robj *o = obj;
1568
1569 #ifdef DEBUG_REFCOUNT
1570     if (o->type == REDIS_STRING)
1571         printf("Decrement '%s'(%p), now is: %d\n",o->ptr,o,o->refcount-1);
1572 #endif
1573     if (--(o->refcount) == 0) {
1574         switch(o->type) {
1575         case REDIS_STRING: freeStringObject(o); break;
1576         case REDIS_LIST: freeListObject(o); break;
1577         case REDIS_SET: freeSetObject(o); break;
1578         case REDIS_HASH: freeHashObject(o); break;
1579         default: assert(0 != 0); break;
1580         }
1581         if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX ||
1582             !listAddNodeHead(server.objfreelist,o))
1583             zfree(o);
1584     }
1585 }
1586
1587 /* Try to share an object against the shared objects pool */
1588 static robj *tryObjectSharing(robj *o) {
1589     struct dictEntry *de;
1590     unsigned long c;
1591
1592     if (o == NULL || server.shareobjects == 0) return o;
1593
1594     assert(o->type == REDIS_STRING);
1595     de = dictFind(server.sharingpool,o);
1596     if (de) {
1597         robj *shared = dictGetEntryKey(de);
1598
1599         c = ((unsigned long) dictGetEntryVal(de))+1;
1600         dictGetEntryVal(de) = (void*) c;
1601         incrRefCount(shared);
1602         decrRefCount(o);
1603         return shared;
1604     } else {
1605         /* Here we are using a stream algorihtm: Every time an object is
1606          * shared we increment its count, everytime there is a miss we
1607          * recrement the counter of a random object. If this object reaches
1608          * zero we remove the object and put the current object instead. */
1609         if (dictSize(server.sharingpool) >=
1610                 server.sharingpoolsize) {
1611             de = dictGetRandomKey(server.sharingpool);
1612             assert(de != NULL);
1613             c = ((unsigned long) dictGetEntryVal(de))-1;
1614             dictGetEntryVal(de) = (void*) c;
1615             if (c == 0) {
1616                 dictDelete(server.sharingpool,de->key);
1617             }
1618         } else {
1619             c = 0; /* If the pool is empty we want to add this object */
1620         }
1621         if (c == 0) {
1622             int retval;
1623
1624             retval = dictAdd(server.sharingpool,o,(void*)1);
1625             assert(retval == DICT_OK);
1626             incrRefCount(o);
1627         }
1628         return o;
1629     }
1630 }
1631
1632 static robj *lookupKey(redisDb *db, robj *key) {
1633     dictEntry *de = dictFind(db->dict,key);
1634     return de ? dictGetEntryVal(de) : NULL;
1635 }
1636
1637 static robj *lookupKeyRead(redisDb *db, robj *key) {
1638     expireIfNeeded(db,key);
1639     return lookupKey(db,key);
1640 }
1641
1642 static robj *lookupKeyWrite(redisDb *db, robj *key) {
1643     deleteIfVolatile(db,key);
1644     return lookupKey(db,key);
1645 }
1646
1647 static int deleteKey(redisDb *db, robj *key) {
1648     int retval;
1649
1650     /* We need to protect key from destruction: after the first dictDelete()
1651      * it may happen that 'key' is no longer valid if we don't increment
1652      * it's count. This may happen when we get the object reference directly
1653      * from the hash table with dictRandomKey() or dict iterators */
1654     incrRefCount(key);
1655     if (dictSize(db->expires)) dictDelete(db->expires,key);
1656     retval = dictDelete(db->dict,key);
1657     decrRefCount(key);
1658
1659     return retval == DICT_OK;
1660 }
1661
1662 /*============================ DB saving/loading ============================ */
1663
1664 static int rdbSaveType(FILE *fp, unsigned char type) {
1665     if (fwrite(&type,1,1,fp) == 0) return -1;
1666     return 0;
1667 }
1668
1669 static int rdbSaveTime(FILE *fp, time_t t) {
1670     int32_t t32 = (int32_t) t;
1671     if (fwrite(&t32,4,1,fp) == 0) return -1;
1672     return 0;
1673 }
1674
1675 /* check rdbLoadLen() comments for more info */
1676 static int rdbSaveLen(FILE *fp, uint32_t len) {
1677     unsigned char buf[2];
1678
1679     if (len < (1<<6)) {
1680         /* Save a 6 bit len */
1681         buf[0] = (len&0xFF)|(REDIS_RDB_6BITLEN<<6);
1682         if (fwrite(buf,1,1,fp) == 0) return -1;
1683     } else if (len < (1<<14)) {
1684         /* Save a 14 bit len */
1685         buf[0] = ((len>>8)&0xFF)|(REDIS_RDB_14BITLEN<<6);
1686         buf[1] = len&0xFF;
1687         if (fwrite(buf,2,1,fp) == 0) return -1;
1688     } else {
1689         /* Save a 32 bit len */
1690         buf[0] = (REDIS_RDB_32BITLEN<<6);
1691         if (fwrite(buf,1,1,fp) == 0) return -1;
1692         len = htonl(len);
1693         if (fwrite(&len,4,1,fp) == 0) return -1;
1694     }
1695     return 0;
1696 }
1697
1698 /* String objects in the form "2391" "-100" without any space and with a
1699  * range of values that can fit in an 8, 16 or 32 bit signed value can be
1700  * encoded as integers to save space */
1701 int rdbTryIntegerEncoding(sds s, unsigned char *enc) {
1702     long long value;
1703     char *endptr, buf[32];
1704
1705     /* Check if it's possible to encode this value as a number */
1706     value = strtoll(s, &endptr, 10);
1707     if (endptr[0] != '\0') return 0;
1708     snprintf(buf,32,"%lld",value);
1709
1710     /* If the number converted back into a string is not identical
1711      * then it's not possible to encode the string as integer */
1712     if (strlen(buf) != sdslen(s) || memcmp(buf,s,sdslen(s))) return 0;
1713
1714     /* Finally check if it fits in our ranges */
1715     if (value >= -(1<<7) && value <= (1<<7)-1) {
1716         enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT8;
1717         enc[1] = value&0xFF;
1718         return 2;
1719     } else if (value >= -(1<<15) && value <= (1<<15)-1) {
1720         enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT16;
1721         enc[1] = value&0xFF;
1722         enc[2] = (value>>8)&0xFF;
1723         return 3;
1724     } else if (value >= -((long long)1<<31) && value <= ((long long)1<<31)-1) {
1725         enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT32;
1726         enc[1] = value&0xFF;
1727         enc[2] = (value>>8)&0xFF;
1728         enc[3] = (value>>16)&0xFF;
1729         enc[4] = (value>>24)&0xFF;
1730         return 5;
1731     } else {
1732         return 0;
1733     }
1734 }
1735
1736 static int rdbSaveLzfStringObject(FILE *fp, robj *obj) {
1737     unsigned int comprlen, outlen;
1738     unsigned char byte;
1739     void *out;
1740
1741     /* We require at least four bytes compression for this to be worth it */
1742     outlen = sdslen(obj->ptr)-4;
1743     if (outlen <= 0) return 0;
1744     if ((out = zmalloc(outlen+1)) == NULL) return 0;
1745     comprlen = lzf_compress(obj->ptr, sdslen(obj->ptr), out, outlen);
1746     if (comprlen == 0) {
1747         zfree(out);
1748         return 0;
1749     }
1750     /* Data compressed! Let's save it on disk */
1751     byte = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_LZF;
1752     if (fwrite(&byte,1,1,fp) == 0) goto writeerr;
1753     if (rdbSaveLen(fp,comprlen) == -1) goto writeerr;
1754     if (rdbSaveLen(fp,sdslen(obj->ptr)) == -1) goto writeerr;
1755     if (fwrite(out,comprlen,1,fp) == 0) goto writeerr;
1756     zfree(out);
1757     return comprlen;
1758
1759 writeerr:
1760     zfree(out);
1761     return -1;
1762 }
1763
1764 /* Save a string objet as [len][data] on disk. If the object is a string
1765  * representation of an integer value we try to safe it in a special form */
1766 static int rdbSaveStringObject(FILE *fp, robj *obj) {
1767     size_t len = sdslen(obj->ptr);
1768     int enclen;
1769
1770     /* Try integer encoding */
1771     if (len <= 11) {
1772         unsigned char buf[5];
1773         if ((enclen = rdbTryIntegerEncoding(obj->ptr,buf)) > 0) {
1774             if (fwrite(buf,enclen,1,fp) == 0) return -1;
1775             return 0;
1776         }
1777     }
1778
1779     /* Try LZF compression - under 20 bytes it's unable to compress even
1780      * aaaaaaaaaaaaaaaaaa so skip it */
1781     if (1 && len > 20) {
1782         int retval;
1783
1784         retval = rdbSaveLzfStringObject(fp,obj);
1785         if (retval == -1) return -1;
1786         if (retval > 0) return 0;
1787         /* retval == 0 means data can't be compressed, save the old way */
1788     }
1789
1790     /* Store verbatim */
1791     if (rdbSaveLen(fp,len) == -1) return -1;
1792     if (len && fwrite(obj->ptr,len,1,fp) == 0) return -1;
1793     return 0;
1794 }
1795
1796 /* Save the DB on disk. Return REDIS_ERR on error, REDIS_OK on success */
1797 static int rdbSave(char *filename) {
1798     dictIterator *di = NULL;
1799     dictEntry *de;
1800     FILE *fp;
1801     char tmpfile[256];
1802     int j;
1803     time_t now = time(NULL);
1804
1805     snprintf(tmpfile,256,"temp-%d.%ld.rdb",(int)time(NULL),(long int)random());
1806     fp = fopen(tmpfile,"w");
1807     if (!fp) {
1808         redisLog(REDIS_WARNING, "Failed saving the DB: %s", strerror(errno));
1809         return REDIS_ERR;
1810     }
1811     if (fwrite("REDIS0001",9,1,fp) == 0) goto werr;
1812     for (j = 0; j < server.dbnum; j++) {
1813         redisDb *db = server.db+j;
1814         dict *d = db->dict;
1815         if (dictSize(d) == 0) continue;
1816         di = dictGetIterator(d);
1817         if (!di) {
1818             fclose(fp);
1819             return REDIS_ERR;
1820         }
1821
1822         /* Write the SELECT DB opcode */
1823         if (rdbSaveType(fp,REDIS_SELECTDB) == -1) goto werr;
1824         if (rdbSaveLen(fp,j) == -1) goto werr;
1825
1826         /* Iterate this DB writing every entry */
1827         while((de = dictNext(di)) != NULL) {
1828             robj *key = dictGetEntryKey(de);
1829             robj *o = dictGetEntryVal(de);
1830             time_t expiretime = getExpire(db,key);
1831
1832             /* Save the expire time */
1833             if (expiretime != -1) {
1834                 /* If this key is already expired skip it */
1835                 if (expiretime < now) continue;
1836                 if (rdbSaveType(fp,REDIS_EXPIRETIME) == -1) goto werr;
1837                 if (rdbSaveTime(fp,expiretime) == -1) goto werr;
1838             }
1839             /* Save the key and associated value */
1840             if (rdbSaveType(fp,o->type) == -1) goto werr;
1841             if (rdbSaveStringObject(fp,key) == -1) goto werr;
1842             if (o->type == REDIS_STRING) {
1843                 /* Save a string value */
1844                 if (rdbSaveStringObject(fp,o) == -1) goto werr;
1845             } else if (o->type == REDIS_LIST) {
1846                 /* Save a list value */
1847                 list *list = o->ptr;
1848                 listNode *ln;
1849
1850                 listRewind(list);
1851                 if (rdbSaveLen(fp,listLength(list)) == -1) goto werr;
1852                 while((ln = listYield(list))) {
1853                     robj *eleobj = listNodeValue(ln);
1854
1855                     if (rdbSaveStringObject(fp,eleobj) == -1) goto werr;
1856                 }
1857             } else if (o->type == REDIS_SET) {
1858                 /* Save a set value */
1859                 dict *set = o->ptr;
1860                 dictIterator *di = dictGetIterator(set);
1861                 dictEntry *de;
1862
1863                 if (!set) oom("dictGetIteraotr");
1864                 if (rdbSaveLen(fp,dictSize(set)) == -1) goto werr;
1865                 while((de = dictNext(di)) != NULL) {
1866                     robj *eleobj = dictGetEntryKey(de);
1867
1868                     if (rdbSaveStringObject(fp,eleobj) == -1) goto werr;
1869                 }
1870                 dictReleaseIterator(di);
1871             } else {
1872                 assert(0 != 0);
1873             }
1874         }
1875         dictReleaseIterator(di);
1876     }
1877     /* EOF opcode */
1878     if (rdbSaveType(fp,REDIS_EOF) == -1) goto werr;
1879
1880     /* Make sure data will not remain on the OS's output buffers */
1881     fflush(fp);
1882     fsync(fileno(fp));
1883     fclose(fp);
1884
1885     /* Use RENAME to make sure the DB file is changed atomically only
1886      * if the generate DB file is ok. */
1887     if (rename(tmpfile,filename) == -1) {
1888         redisLog(REDIS_WARNING,"Error moving temp DB file on the final destionation: %s", strerror(errno));
1889         unlink(tmpfile);
1890         return REDIS_ERR;
1891     }
1892     redisLog(REDIS_NOTICE,"DB saved on disk");
1893     server.dirty = 0;
1894     server.lastsave = time(NULL);
1895     return REDIS_OK;
1896
1897 werr:
1898     fclose(fp);
1899     unlink(tmpfile);
1900     redisLog(REDIS_WARNING,"Write error saving DB on disk: %s", strerror(errno));
1901     if (di) dictReleaseIterator(di);
1902     return REDIS_ERR;
1903 }
1904
1905 static int rdbSaveBackground(char *filename) {
1906     pid_t childpid;
1907
1908     if (server.bgsaveinprogress) return REDIS_ERR;
1909     if ((childpid = fork()) == 0) {
1910         /* Child */
1911         close(server.fd);
1912         if (rdbSave(filename) == REDIS_OK) {
1913             exit(0);
1914         } else {
1915             exit(1);
1916         }
1917     } else {
1918         /* Parent */
1919         if (childpid == -1) {
1920             redisLog(REDIS_WARNING,"Can't save in background: fork: %s",
1921                 strerror(errno));
1922             return REDIS_ERR;
1923         }
1924         redisLog(REDIS_NOTICE,"Background saving started by pid %d",childpid);
1925         server.bgsaveinprogress = 1;
1926         return REDIS_OK;
1927     }
1928     return REDIS_OK; /* unreached */
1929 }
1930
1931 static int rdbLoadType(FILE *fp) {
1932     unsigned char type;
1933     if (fread(&type,1,1,fp) == 0) return -1;
1934     return type;
1935 }
1936
1937 static time_t rdbLoadTime(FILE *fp) {
1938     int32_t t32;
1939     if (fread(&t32,4,1,fp) == 0) return -1;
1940     return (time_t) t32;
1941 }
1942
1943 /* Load an encoded length from the DB, see the REDIS_RDB_* defines on the top
1944  * of this file for a description of how this are stored on disk.
1945  *
1946  * isencoded is set to 1 if the readed length is not actually a length but
1947  * an "encoding type", check the above comments for more info */
1948 static uint32_t rdbLoadLen(FILE *fp, int rdbver, int *isencoded) {
1949     unsigned char buf[2];
1950     uint32_t len;
1951
1952     if (isencoded) *isencoded = 0;
1953     if (rdbver == 0) {
1954         if (fread(&len,4,1,fp) == 0) return REDIS_RDB_LENERR;
1955         return ntohl(len);
1956     } else {
1957         int type;
1958
1959         if (fread(buf,1,1,fp) == 0) return REDIS_RDB_LENERR;
1960         type = (buf[0]&0xC0)>>6;
1961         if (type == REDIS_RDB_6BITLEN) {
1962             /* Read a 6 bit len */
1963             return buf[0]&0x3F;
1964         } else if (type == REDIS_RDB_ENCVAL) {
1965             /* Read a 6 bit len encoding type */
1966             if (isencoded) *isencoded = 1;
1967             return buf[0]&0x3F;
1968         } else if (type == REDIS_RDB_14BITLEN) {
1969             /* Read a 14 bit len */
1970             if (fread(buf+1,1,1,fp) == 0) return REDIS_RDB_LENERR;
1971             return ((buf[0]&0x3F)<<8)|buf[1];
1972         } else {
1973             /* Read a 32 bit len */
1974             if (fread(&len,4,1,fp) == 0) return REDIS_RDB_LENERR;
1975             return ntohl(len);
1976         }
1977     }
1978 }
1979
1980 static robj *rdbLoadIntegerObject(FILE *fp, int enctype) {
1981     unsigned char enc[4];
1982     long long val;
1983
1984     if (enctype == REDIS_RDB_ENC_INT8) {
1985         if (fread(enc,1,1,fp) == 0) return NULL;
1986         val = (signed char)enc[0];
1987     } else if (enctype == REDIS_RDB_ENC_INT16) {
1988         uint16_t v;
1989         if (fread(enc,2,1,fp) == 0) return NULL;
1990         v = enc[0]|(enc[1]<<8);
1991         val = (int16_t)v;
1992     } else if (enctype == REDIS_RDB_ENC_INT32) {
1993         uint32_t v;
1994         if (fread(enc,4,1,fp) == 0) return NULL;
1995         v = enc[0]|(enc[1]<<8)|(enc[2]<<16)|(enc[3]<<24);
1996         val = (int32_t)v;
1997     } else {
1998         val = 0; /* anti-warning */
1999         assert(0!=0);
2000     }
2001     return createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",val));
2002 }
2003
2004 static robj *rdbLoadLzfStringObject(FILE*fp, int rdbver) {
2005     unsigned int len, clen;
2006     unsigned char *c = NULL;
2007     sds val = NULL;
2008
2009     if ((clen = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR) return NULL;
2010     if ((len = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR) return NULL;
2011     if ((c = zmalloc(clen)) == NULL) goto err;
2012     if ((val = sdsnewlen(NULL,len)) == NULL) goto err;
2013     if (fread(c,clen,1,fp) == 0) goto err;
2014     if (lzf_decompress(c,clen,val,len) == 0) goto err;
2015     return createObject(REDIS_STRING,val);
2016 err:
2017     zfree(c);
2018     sdsfree(val);
2019     return NULL;
2020 }
2021
2022 static robj *rdbLoadStringObject(FILE*fp, int rdbver) {
2023     int isencoded;
2024     uint32_t len;
2025     sds val;
2026
2027     len = rdbLoadLen(fp,rdbver,&isencoded);
2028     if (isencoded) {
2029         switch(len) {
2030         case REDIS_RDB_ENC_INT8:
2031         case REDIS_RDB_ENC_INT16:
2032         case REDIS_RDB_ENC_INT32:
2033             return tryObjectSharing(rdbLoadIntegerObject(fp,len));
2034         case REDIS_RDB_ENC_LZF:
2035             return tryObjectSharing(rdbLoadLzfStringObject(fp,rdbver));
2036         default:
2037             assert(0!=0);
2038         }
2039     }
2040
2041     if (len == REDIS_RDB_LENERR) return NULL;
2042     val = sdsnewlen(NULL,len);
2043     if (len && fread(val,len,1,fp) == 0) {
2044         sdsfree(val);
2045         return NULL;
2046     }
2047     return tryObjectSharing(createObject(REDIS_STRING,val));
2048 }
2049
2050 static int rdbLoad(char *filename) {
2051     FILE *fp;
2052     robj *keyobj = NULL;
2053     uint32_t dbid;
2054     int type, retval, rdbver;
2055     dict *d = server.db[0].dict;
2056     redisDb *db = server.db+0;
2057     char buf[1024];
2058     time_t expiretime = -1, now = time(NULL);
2059
2060     fp = fopen(filename,"r");
2061     if (!fp) return REDIS_ERR;
2062     if (fread(buf,9,1,fp) == 0) goto eoferr;
2063     buf[9] = '\0';
2064     if (memcmp(buf,"REDIS",5) != 0) {
2065         fclose(fp);
2066         redisLog(REDIS_WARNING,"Wrong signature trying to load DB from file");
2067         return REDIS_ERR;
2068     }
2069     rdbver = atoi(buf+5);
2070     if (rdbver > 1) {
2071         fclose(fp);
2072         redisLog(REDIS_WARNING,"Can't handle RDB format version %d",rdbver);
2073         return REDIS_ERR;
2074     }
2075     while(1) {
2076         robj *o;
2077
2078         /* Read type. */
2079         if ((type = rdbLoadType(fp)) == -1) goto eoferr;
2080         if (type == REDIS_EXPIRETIME) {
2081             if ((expiretime = rdbLoadTime(fp)) == -1) goto eoferr;
2082             /* We read the time so we need to read the object type again */
2083             if ((type = rdbLoadType(fp)) == -1) goto eoferr;
2084         }
2085         if (type == REDIS_EOF) break;
2086         /* Handle SELECT DB opcode as a special case */
2087         if (type == REDIS_SELECTDB) {
2088             if ((dbid = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR)
2089                 goto eoferr;
2090             if (dbid >= (unsigned)server.dbnum) {
2091                 redisLog(REDIS_WARNING,"FATAL: Data file was created with a Redis server configured to handle more than %d databases. Exiting\n", server.dbnum);
2092                 exit(1);
2093             }
2094             db = server.db+dbid;
2095             d = db->dict;
2096             continue;
2097         }
2098         /* Read key */
2099         if ((keyobj = rdbLoadStringObject(fp,rdbver)) == NULL) goto eoferr;
2100
2101         if (type == REDIS_STRING) {
2102             /* Read string value */
2103             if ((o = rdbLoadStringObject(fp,rdbver)) == NULL) goto eoferr;
2104         } else if (type == REDIS_LIST || type == REDIS_SET) {
2105             /* Read list/set value */
2106             uint32_t listlen;
2107
2108             if ((listlen = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR)
2109                 goto eoferr;
2110             o = (type == REDIS_LIST) ? createListObject() : createSetObject();
2111             /* Load every single element of the list/set */
2112             while(listlen--) {
2113                 robj *ele;
2114
2115                 if ((ele = rdbLoadStringObject(fp,rdbver)) == NULL) goto eoferr;
2116                 if (type == REDIS_LIST) {
2117                     if (!listAddNodeTail((list*)o->ptr,ele))
2118                         oom("listAddNodeTail");
2119                 } else {
2120                     if (dictAdd((dict*)o->ptr,ele,NULL) == DICT_ERR)
2121                         oom("dictAdd");
2122                 }
2123             }
2124         } else {
2125             assert(0 != 0);
2126         }
2127         /* Add the new object in the hash table */
2128         retval = dictAdd(d,keyobj,o);
2129         if (retval == DICT_ERR) {
2130             redisLog(REDIS_WARNING,"Loading DB, duplicated key (%s) found! Unrecoverable error, exiting now.", keyobj->ptr);
2131             exit(1);
2132         }
2133         /* Set the expire time if needed */
2134         if (expiretime != -1) {
2135             setExpire(db,keyobj,expiretime);
2136             /* Delete this key if already expired */
2137             if (expiretime < now) deleteKey(db,keyobj);
2138             expiretime = -1;
2139         }
2140         keyobj = o = NULL;
2141     }
2142     fclose(fp);
2143     return REDIS_OK;
2144
2145 eoferr: /* unexpected end of file is handled here with a fatal exit */
2146     if (keyobj) decrRefCount(keyobj);
2147     redisLog(REDIS_WARNING,"Short read or OOM loading DB. Unrecoverable error, exiting now.");
2148     exit(1);
2149     return REDIS_ERR; /* Just to avoid warning */
2150 }
2151
2152 /*================================== Commands =============================== */
2153
2154 static void authCommand(redisClient *c) {
2155     if (!server.requirepass || !strcmp(c->argv[1]->ptr, server.requirepass)) {
2156       c->authenticated = 1;
2157       addReply(c,shared.ok);
2158     } else {
2159       c->authenticated = 0;
2160       addReply(c,shared.err);
2161     }
2162 }
2163
2164 static void pingCommand(redisClient *c) {
2165     addReply(c,shared.pong);
2166 }
2167
2168 static void echoCommand(redisClient *c) {
2169     addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",
2170         (int)sdslen(c->argv[1]->ptr)));
2171     addReply(c,c->argv[1]);
2172     addReply(c,shared.crlf);
2173 }
2174
2175 /*=================================== Strings =============================== */
2176
2177 static void setGenericCommand(redisClient *c, int nx) {
2178     int retval;
2179
2180     retval = dictAdd(c->db->dict,c->argv[1],c->argv[2]);
2181     if (retval == DICT_ERR) {
2182         if (!nx) {
2183             dictReplace(c->db->dict,c->argv[1],c->argv[2]);
2184             incrRefCount(c->argv[2]);
2185         } else {
2186             addReply(c,shared.czero);
2187             return;
2188         }
2189     } else {
2190         incrRefCount(c->argv[1]);
2191         incrRefCount(c->argv[2]);
2192     }
2193     server.dirty++;
2194     removeExpire(c->db,c->argv[1]);
2195     addReply(c, nx ? shared.cone : shared.ok);
2196 }
2197
2198 static void setCommand(redisClient *c) {
2199     setGenericCommand(c,0);
2200 }
2201
2202 static void setnxCommand(redisClient *c) {
2203     setGenericCommand(c,1);
2204 }
2205
2206 static void getCommand(redisClient *c) {
2207     robj *o = lookupKeyRead(c->db,c->argv[1]);
2208
2209     if (o == NULL) {
2210         addReply(c,shared.nullbulk);
2211     } else {
2212         if (o->type != REDIS_STRING) {
2213             addReply(c,shared.wrongtypeerr);
2214         } else {
2215             addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(o->ptr)));
2216             addReply(c,o);
2217             addReply(c,shared.crlf);
2218         }
2219     }
2220 }
2221
2222 static void getSetCommand(redisClient *c) {
2223     getCommand(c);
2224     if (dictAdd(c->db->dict,c->argv[1],c->argv[2]) == DICT_ERR) {
2225         dictReplace(c->db->dict,c->argv[1],c->argv[2]);
2226     } else {
2227         incrRefCount(c->argv[1]);
2228     }
2229     incrRefCount(c->argv[2]);
2230     server.dirty++;
2231     removeExpire(c->db,c->argv[1]);
2232 }
2233
2234 static void mgetCommand(redisClient *c) {
2235     int j;
2236
2237     addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",c->argc-1));
2238     for (j = 1; j < c->argc; j++) {
2239         robj *o = lookupKeyRead(c->db,c->argv[j]);
2240         if (o == NULL) {
2241             addReply(c,shared.nullbulk);
2242         } else {
2243             if (o->type != REDIS_STRING) {
2244                 addReply(c,shared.nullbulk);
2245             } else {
2246                 addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(o->ptr)));
2247                 addReply(c,o);
2248                 addReply(c,shared.crlf);
2249             }
2250         }
2251     }
2252 }
2253
2254 static void incrDecrCommand(redisClient *c, long long incr) {
2255     long long value;
2256     int retval;
2257     robj *o;
2258
2259     o = lookupKeyWrite(c->db,c->argv[1]);
2260     if (o == NULL) {
2261         value = 0;
2262     } else {
2263         if (o->type != REDIS_STRING) {
2264             value = 0;
2265         } else {
2266             char *eptr;
2267
2268             value = strtoll(o->ptr, &eptr, 10);
2269         }
2270     }
2271
2272     value += incr;
2273     o = createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",value));
2274     retval = dictAdd(c->db->dict,c->argv[1],o);
2275     if (retval == DICT_ERR) {
2276         dictReplace(c->db->dict,c->argv[1],o);
2277         removeExpire(c->db,c->argv[1]);
2278     } else {
2279         incrRefCount(c->argv[1]);
2280     }
2281     server.dirty++;
2282     addReply(c,shared.colon);
2283     addReply(c,o);
2284     addReply(c,shared.crlf);
2285 }
2286
2287 static void incrCommand(redisClient *c) {
2288     incrDecrCommand(c,1);
2289 }
2290
2291 static void decrCommand(redisClient *c) {
2292     incrDecrCommand(c,-1);
2293 }
2294
2295 static void incrbyCommand(redisClient *c) {
2296     long long incr = strtoll(c->argv[2]->ptr, NULL, 10);
2297     incrDecrCommand(c,incr);
2298 }
2299
2300 static void decrbyCommand(redisClient *c) {
2301     long long incr = strtoll(c->argv[2]->ptr, NULL, 10);
2302     incrDecrCommand(c,-incr);
2303 }
2304
2305 /* ========================= Type agnostic commands ========================= */
2306
2307 static void delCommand(redisClient *c) {
2308     if (deleteKey(c->db,c->argv[1])) {
2309         server.dirty++;
2310         addReply(c,shared.cone);
2311     } else {
2312         addReply(c,shared.czero);
2313     }
2314 }
2315
2316 static void existsCommand(redisClient *c) {
2317     addReply(c,lookupKeyRead(c->db,c->argv[1]) ? shared.cone : shared.czero);
2318 }
2319
2320 static void selectCommand(redisClient *c) {
2321     int id = atoi(c->argv[1]->ptr);
2322
2323     if (selectDb(c,id) == REDIS_ERR) {
2324         addReplySds(c,sdsnew("-ERR invalid DB index\r\n"));
2325     } else {
2326         addReply(c,shared.ok);
2327     }
2328 }
2329
2330 static void randomkeyCommand(redisClient *c) {
2331     dictEntry *de;
2332
2333     while(1) {
2334         de = dictGetRandomKey(c->db->dict);
2335         if (!de || expireIfNeeded(c->db,dictGetEntryKey(de)) == 0) break;
2336     }
2337     if (de == NULL) {
2338         addReply(c,shared.plus);
2339         addReply(c,shared.crlf);
2340     } else {
2341         addReply(c,shared.plus);
2342         addReply(c,dictGetEntryKey(de));
2343         addReply(c,shared.crlf);
2344     }
2345 }
2346
2347 static void keysCommand(redisClient *c) {
2348     dictIterator *di;
2349     dictEntry *de;
2350     sds pattern = c->argv[1]->ptr;
2351     int plen = sdslen(pattern);
2352     int numkeys = 0, keyslen = 0;
2353     robj *lenobj = createObject(REDIS_STRING,NULL);
2354
2355     di = dictGetIterator(c->db->dict);
2356     if (!di) oom("dictGetIterator");
2357     addReply(c,lenobj);
2358     decrRefCount(lenobj);
2359     while((de = dictNext(di)) != NULL) {
2360         robj *keyobj = dictGetEntryKey(de);
2361
2362         sds key = keyobj->ptr;
2363         if ((pattern[0] == '*' && pattern[1] == '\0') ||
2364             stringmatchlen(pattern,plen,key,sdslen(key),0)) {
2365             if (expireIfNeeded(c->db,keyobj) == 0) {
2366                 if (numkeys != 0)
2367                     addReply(c,shared.space);
2368                 addReply(c,keyobj);
2369                 numkeys++;
2370                 keyslen += sdslen(key);
2371             }
2372         }
2373     }
2374     dictReleaseIterator(di);
2375     lenobj->ptr = sdscatprintf(sdsempty(),"$%lu\r\n",keyslen+(numkeys ? (numkeys-1) : 0));
2376     addReply(c,shared.crlf);
2377 }
2378
2379 static void dbsizeCommand(redisClient *c) {
2380     addReplySds(c,
2381         sdscatprintf(sdsempty(),":%lu\r\n",dictSize(c->db->dict)));
2382 }
2383
2384 static void lastsaveCommand(redisClient *c) {
2385     addReplySds(c,
2386         sdscatprintf(sdsempty(),":%lu\r\n",server.lastsave));
2387 }
2388
2389 static void typeCommand(redisClient *c) {
2390     robj *o;
2391     char *type;
2392
2393     o = lookupKeyRead(c->db,c->argv[1]);
2394     if (o == NULL) {
2395         type = "+none";
2396     } else {
2397         switch(o->type) {
2398         case REDIS_STRING: type = "+string"; break;
2399         case REDIS_LIST: type = "+list"; break;
2400         case REDIS_SET: type = "+set"; break;
2401         default: type = "unknown"; break;
2402         }
2403     }
2404     addReplySds(c,sdsnew(type));
2405     addReply(c,shared.crlf);
2406 }
2407
2408 static void saveCommand(redisClient *c) {
2409     if (server.bgsaveinprogress) {
2410         addReplySds(c,sdsnew("-ERR background save in progress\r\n"));
2411         return;
2412     }
2413     if (rdbSave(server.dbfilename) == REDIS_OK) {
2414         addReply(c,shared.ok);
2415     } else {
2416         addReply(c,shared.err);
2417     }
2418 }
2419
2420 static void bgsaveCommand(redisClient *c) {
2421     if (server.bgsaveinprogress) {
2422         addReplySds(c,sdsnew("-ERR background save already in progress\r\n"));
2423         return;
2424     }
2425     if (rdbSaveBackground(server.dbfilename) == REDIS_OK) {
2426         addReply(c,shared.ok);
2427     } else {
2428         addReply(c,shared.err);
2429     }
2430 }
2431
2432 static void shutdownCommand(redisClient *c) {
2433     redisLog(REDIS_WARNING,"User requested shutdown, saving DB...");
2434     /* XXX: TODO kill the child if there is a bgsave in progress */
2435     if (rdbSave(server.dbfilename) == REDIS_OK) {
2436         if (server.daemonize) {
2437             unlink(server.pidfile);
2438         }
2439         redisLog(REDIS_WARNING,"%zu bytes used at exit",zmalloc_used_memory());
2440         redisLog(REDIS_WARNING,"Server exit now, bye bye...");
2441         exit(1);
2442     } else {
2443         redisLog(REDIS_WARNING,"Error trying to save the DB, can't exit");
2444         addReplySds(c,sdsnew("-ERR can't quit, problems saving the DB\r\n"));
2445     }
2446 }
2447
2448 static void renameGenericCommand(redisClient *c, int nx) {
2449     robj *o;
2450
2451     /* To use the same key as src and dst is probably an error */
2452     if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) {
2453         addReply(c,shared.sameobjecterr);
2454         return;
2455     }
2456
2457     o = lookupKeyWrite(c->db,c->argv[1]);
2458     if (o == NULL) {
2459         addReply(c,shared.nokeyerr);
2460         return;
2461     }
2462     incrRefCount(o);
2463     deleteIfVolatile(c->db,c->argv[2]);
2464     if (dictAdd(c->db->dict,c->argv[2],o) == DICT_ERR) {
2465         if (nx) {
2466             decrRefCount(o);
2467             addReply(c,shared.czero);
2468             return;
2469         }
2470         dictReplace(c->db->dict,c->argv[2],o);
2471     } else {
2472         incrRefCount(c->argv[2]);
2473     }
2474     deleteKey(c->db,c->argv[1]);
2475     server.dirty++;
2476     addReply(c,nx ? shared.cone : shared.ok);
2477 }
2478
2479 static void renameCommand(redisClient *c) {
2480     renameGenericCommand(c,0);
2481 }
2482
2483 static void renamenxCommand(redisClient *c) {
2484     renameGenericCommand(c,1);
2485 }
2486
2487 static void moveCommand(redisClient *c) {
2488     robj *o;
2489     redisDb *src, *dst;
2490     int srcid;
2491
2492     /* Obtain source and target DB pointers */
2493     src = c->db;
2494     srcid = c->db->id;
2495     if (selectDb(c,atoi(c->argv[2]->ptr)) == REDIS_ERR) {
2496         addReply(c,shared.outofrangeerr);
2497         return;
2498     }
2499     dst = c->db;
2500     selectDb(c,srcid); /* Back to the source DB */
2501
2502     /* If the user is moving using as target the same
2503      * DB as the source DB it is probably an error. */
2504     if (src == dst) {
2505         addReply(c,shared.sameobjecterr);
2506         return;
2507     }
2508
2509     /* Check if the element exists and get a reference */
2510     o = lookupKeyWrite(c->db,c->argv[1]);
2511     if (!o) {
2512         addReply(c,shared.czero);
2513         return;
2514     }
2515
2516     /* Try to add the element to the target DB */
2517     deleteIfVolatile(dst,c->argv[1]);
2518     if (dictAdd(dst->dict,c->argv[1],o) == DICT_ERR) {
2519         addReply(c,shared.czero);
2520         return;
2521     }
2522     incrRefCount(c->argv[1]);
2523     incrRefCount(o);
2524
2525     /* OK! key moved, free the entry in the source DB */
2526     deleteKey(src,c->argv[1]);
2527     server.dirty++;
2528     addReply(c,shared.cone);
2529 }
2530
2531 /* =================================== Lists ================================ */
2532 static void pushGenericCommand(redisClient *c, int where) {
2533     robj *lobj;
2534     list *list;
2535
2536     lobj = lookupKeyWrite(c->db,c->argv[1]);
2537     if (lobj == NULL) {
2538         lobj = createListObject();
2539         list = lobj->ptr;
2540         if (where == REDIS_HEAD) {
2541             if (!listAddNodeHead(list,c->argv[2])) oom("listAddNodeHead");
2542         } else {
2543             if (!listAddNodeTail(list,c->argv[2])) oom("listAddNodeTail");
2544         }
2545         dictAdd(c->db->dict,c->argv[1],lobj);
2546         incrRefCount(c->argv[1]);
2547         incrRefCount(c->argv[2]);
2548     } else {
2549         if (lobj->type != REDIS_LIST) {
2550             addReply(c,shared.wrongtypeerr);
2551             return;
2552         }
2553         list = lobj->ptr;
2554         if (where == REDIS_HEAD) {
2555             if (!listAddNodeHead(list,c->argv[2])) oom("listAddNodeHead");
2556         } else {
2557             if (!listAddNodeTail(list,c->argv[2])) oom("listAddNodeTail");
2558         }
2559         incrRefCount(c->argv[2]);
2560     }
2561     server.dirty++;
2562     addReply(c,shared.ok);
2563 }
2564
2565 static void lpushCommand(redisClient *c) {
2566     pushGenericCommand(c,REDIS_HEAD);
2567 }
2568
2569 static void rpushCommand(redisClient *c) {
2570     pushGenericCommand(c,REDIS_TAIL);
2571 }
2572
2573 static void llenCommand(redisClient *c) {
2574     robj *o;
2575     list *l;
2576
2577     o = lookupKeyRead(c->db,c->argv[1]);
2578     if (o == NULL) {
2579         addReply(c,shared.czero);
2580         return;
2581     } else {
2582         if (o->type != REDIS_LIST) {
2583             addReply(c,shared.wrongtypeerr);
2584         } else {
2585             l = o->ptr;
2586             addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",listLength(l)));
2587         }
2588     }
2589 }
2590
2591 static void lindexCommand(redisClient *c) {
2592     robj *o;
2593     int index = atoi(c->argv[2]->ptr);
2594
2595     o = lookupKeyRead(c->db,c->argv[1]);
2596     if (o == NULL) {
2597         addReply(c,shared.nullbulk);
2598     } else {
2599         if (o->type != REDIS_LIST) {
2600             addReply(c,shared.wrongtypeerr);
2601         } else {
2602             list *list = o->ptr;
2603             listNode *ln;
2604
2605             ln = listIndex(list, index);
2606             if (ln == NULL) {
2607                 addReply(c,shared.nullbulk);
2608             } else {
2609                 robj *ele = listNodeValue(ln);
2610                 addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(ele->ptr)));
2611                 addReply(c,ele);
2612                 addReply(c,shared.crlf);
2613             }
2614         }
2615     }
2616 }
2617
2618 static void lsetCommand(redisClient *c) {
2619     robj *o;
2620     int index = atoi(c->argv[2]->ptr);
2621
2622     o = lookupKeyWrite(c->db,c->argv[1]);
2623     if (o == NULL) {
2624         addReply(c,shared.nokeyerr);
2625     } else {
2626         if (o->type != REDIS_LIST) {
2627             addReply(c,shared.wrongtypeerr);
2628         } else {
2629             list *list = o->ptr;
2630             listNode *ln;
2631
2632             ln = listIndex(list, index);
2633             if (ln == NULL) {
2634                 addReply(c,shared.outofrangeerr);
2635             } else {
2636                 robj *ele = listNodeValue(ln);
2637
2638                 decrRefCount(ele);
2639                 listNodeValue(ln) = c->argv[3];
2640                 incrRefCount(c->argv[3]);
2641                 addReply(c,shared.ok);
2642                 server.dirty++;
2643             }
2644         }
2645     }
2646 }
2647
2648 static void popGenericCommand(redisClient *c, int where) {
2649     robj *o;
2650
2651     o = lookupKeyWrite(c->db,c->argv[1]);
2652     if (o == NULL) {
2653         addReply(c,shared.nullbulk);
2654     } else {
2655         if (o->type != REDIS_LIST) {
2656             addReply(c,shared.wrongtypeerr);
2657         } else {
2658             list *list = o->ptr;
2659             listNode *ln;
2660
2661             if (where == REDIS_HEAD)
2662                 ln = listFirst(list);
2663             else
2664                 ln = listLast(list);
2665
2666             if (ln == NULL) {
2667                 addReply(c,shared.nullbulk);
2668             } else {
2669                 robj *ele = listNodeValue(ln);
2670                 addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(ele->ptr)));
2671                 addReply(c,ele);
2672                 addReply(c,shared.crlf);
2673                 listDelNode(list,ln);
2674                 server.dirty++;
2675             }
2676         }
2677     }
2678 }
2679
2680 static void lpopCommand(redisClient *c) {
2681     popGenericCommand(c,REDIS_HEAD);
2682 }
2683
2684 static void rpopCommand(redisClient *c) {
2685     popGenericCommand(c,REDIS_TAIL);
2686 }
2687
2688 static void lrangeCommand(redisClient *c) {
2689     robj *o;
2690     int start = atoi(c->argv[2]->ptr);
2691     int end = atoi(c->argv[3]->ptr);
2692
2693     o = lookupKeyRead(c->db,c->argv[1]);
2694     if (o == NULL) {
2695         addReply(c,shared.nullmultibulk);
2696     } else {
2697         if (o->type != REDIS_LIST) {
2698             addReply(c,shared.wrongtypeerr);
2699         } else {
2700             list *list = o->ptr;
2701             listNode *ln;
2702             int llen = listLength(list);
2703             int rangelen, j;
2704             robj *ele;
2705
2706             /* convert negative indexes */
2707             if (start < 0) start = llen+start;
2708             if (end < 0) end = llen+end;
2709             if (start < 0) start = 0;
2710             if (end < 0) end = 0;
2711
2712             /* indexes sanity checks */
2713             if (start > end || start >= llen) {
2714                 /* Out of range start or start > end result in empty list */
2715                 addReply(c,shared.emptymultibulk);
2716                 return;
2717             }
2718             if (end >= llen) end = llen-1;
2719             rangelen = (end-start)+1;
2720
2721             /* Return the result in form of a multi-bulk reply */
2722             ln = listIndex(list, start);
2723             addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",rangelen));
2724             for (j = 0; j < rangelen; j++) {
2725                 ele = listNodeValue(ln);
2726                 addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(ele->ptr)));
2727                 addReply(c,ele);
2728                 addReply(c,shared.crlf);
2729                 ln = ln->next;
2730             }
2731         }
2732     }
2733 }
2734
2735 static void ltrimCommand(redisClient *c) {
2736     robj *o;
2737     int start = atoi(c->argv[2]->ptr);
2738     int end = atoi(c->argv[3]->ptr);
2739
2740     o = lookupKeyWrite(c->db,c->argv[1]);
2741     if (o == NULL) {
2742         addReply(c,shared.nokeyerr);
2743     } else {
2744         if (o->type != REDIS_LIST) {
2745             addReply(c,shared.wrongtypeerr);
2746         } else {
2747             list *list = o->ptr;
2748             listNode *ln;
2749             int llen = listLength(list);
2750             int j, ltrim, rtrim;
2751
2752             /* convert negative indexes */
2753             if (start < 0) start = llen+start;
2754             if (end < 0) end = llen+end;
2755             if (start < 0) start = 0;
2756             if (end < 0) end = 0;
2757
2758             /* indexes sanity checks */
2759             if (start > end || start >= llen) {
2760                 /* Out of range start or start > end result in empty list */
2761                 ltrim = llen;
2762                 rtrim = 0;
2763             } else {
2764                 if (end >= llen) end = llen-1;
2765                 ltrim = start;
2766                 rtrim = llen-end-1;
2767             }
2768
2769             /* Remove list elements to perform the trim */
2770             for (j = 0; j < ltrim; j++) {
2771                 ln = listFirst(list);
2772                 listDelNode(list,ln);
2773             }
2774             for (j = 0; j < rtrim; j++) {
2775                 ln = listLast(list);
2776                 listDelNode(list,ln);
2777             }
2778             addReply(c,shared.ok);
2779             server.dirty++;
2780         }
2781     }
2782 }
2783
2784 static void lremCommand(redisClient *c) {
2785     robj *o;
2786
2787     o = lookupKeyWrite(c->db,c->argv[1]);
2788     if (o == NULL) {
2789         addReply(c,shared.nokeyerr);
2790     } else {
2791         if (o->type != REDIS_LIST) {
2792             addReply(c,shared.wrongtypeerr);
2793         } else {
2794             list *list = o->ptr;
2795             listNode *ln, *next;
2796             int toremove = atoi(c->argv[2]->ptr);
2797             int removed = 0;
2798             int fromtail = 0;
2799
2800             if (toremove < 0) {
2801                 toremove = -toremove;
2802                 fromtail = 1;
2803             }
2804             ln = fromtail ? list->tail : list->head;
2805             while (ln) {
2806                 robj *ele = listNodeValue(ln);
2807
2808                 next = fromtail ? ln->prev : ln->next;
2809                 if (sdscmp(ele->ptr,c->argv[3]->ptr) == 0) {
2810                     listDelNode(list,ln);
2811                     server.dirty++;
2812                     removed++;
2813                     if (toremove && removed == toremove) break;
2814                 }
2815                 ln = next;
2816             }
2817             addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",removed));
2818         }
2819     }
2820 }
2821
2822 /* ==================================== Sets ================================ */
2823
2824 static void saddCommand(redisClient *c) {
2825     robj *set;
2826
2827     set = lookupKeyWrite(c->db,c->argv[1]);
2828     if (set == NULL) {
2829         set = createSetObject();
2830         dictAdd(c->db->dict,c->argv[1],set);
2831         incrRefCount(c->argv[1]);
2832     } else {
2833         if (set->type != REDIS_SET) {
2834             addReply(c,shared.wrongtypeerr);
2835             return;
2836         }
2837     }
2838     if (dictAdd(set->ptr,c->argv[2],NULL) == DICT_OK) {
2839         incrRefCount(c->argv[2]);
2840         server.dirty++;
2841         addReply(c,shared.cone);
2842     } else {
2843         addReply(c,shared.czero);
2844     }
2845 }
2846
2847 static void sremCommand(redisClient *c) {
2848     robj *set;
2849
2850     set = lookupKeyWrite(c->db,c->argv[1]);
2851     if (set == NULL) {
2852         addReply(c,shared.czero);
2853     } else {
2854         if (set->type != REDIS_SET) {
2855             addReply(c,shared.wrongtypeerr);
2856             return;
2857         }
2858         if (dictDelete(set->ptr,c->argv[2]) == DICT_OK) {
2859             server.dirty++;
2860             addReply(c,shared.cone);
2861         } else {
2862             addReply(c,shared.czero);
2863         }
2864     }
2865 }
2866
2867 static void smoveCommand(redisClient *c) {
2868     robj *srcset, *dstset;
2869
2870     srcset = lookupKeyWrite(c->db,c->argv[1]);
2871     dstset = lookupKeyWrite(c->db,c->argv[2]);
2872
2873     /* If the source key does not exist return 0, if it's of the wrong type
2874      * raise an error */
2875     if (srcset == NULL || srcset->type != REDIS_SET) {
2876         addReply(c, srcset ? shared.wrongtypeerr : shared.czero);
2877         return;
2878     }
2879     /* Error if the destination key is not a set as well */
2880     if (dstset && dstset->type != REDIS_SET) {
2881         addReply(c,shared.wrongtypeerr);
2882         return;
2883     }
2884     /* Remove the element from the source set */
2885     if (dictDelete(srcset->ptr,c->argv[3]) == DICT_ERR) {
2886         /* Key not found in the src set! return zero */
2887         addReply(c,shared.czero);
2888         return;
2889     }
2890     server.dirty++;
2891     /* Add the element to the destination set */
2892     if (!dstset) {
2893         dstset = createSetObject();
2894         dictAdd(c->db->dict,c->argv[2],dstset);
2895         incrRefCount(c->argv[2]);
2896     }
2897     if (dictAdd(dstset->ptr,c->argv[3],NULL) == DICT_OK)
2898         incrRefCount(c->argv[3]);
2899     addReply(c,shared.cone);
2900 }
2901
2902 static void sismemberCommand(redisClient *c) {
2903     robj *set;
2904
2905     set = lookupKeyRead(c->db,c->argv[1]);
2906     if (set == NULL) {
2907         addReply(c,shared.czero);
2908     } else {
2909         if (set->type != REDIS_SET) {
2910             addReply(c,shared.wrongtypeerr);
2911             return;
2912         }
2913         if (dictFind(set->ptr,c->argv[2]))
2914             addReply(c,shared.cone);
2915         else
2916             addReply(c,shared.czero);
2917     }
2918 }
2919
2920 static void scardCommand(redisClient *c) {
2921     robj *o;
2922     dict *s;
2923
2924     o = lookupKeyRead(c->db,c->argv[1]);
2925     if (o == NULL) {
2926         addReply(c,shared.czero);
2927         return;
2928     } else {
2929         if (o->type != REDIS_SET) {
2930             addReply(c,shared.wrongtypeerr);
2931         } else {
2932             s = o->ptr;
2933             addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",
2934                 dictSize(s)));
2935         }
2936     }
2937 }
2938
2939 static int qsortCompareSetsByCardinality(const void *s1, const void *s2) {
2940     dict **d1 = (void*) s1, **d2 = (void*) s2;
2941
2942     return dictSize(*d1)-dictSize(*d2);
2943 }
2944
2945 static void sinterGenericCommand(redisClient *c, robj **setskeys, int setsnum, robj *dstkey) {
2946     dict **dv = zmalloc(sizeof(dict*)*setsnum);
2947     dictIterator *di;
2948     dictEntry *de;
2949     robj *lenobj = NULL, *dstset = NULL;
2950     int j, cardinality = 0;
2951
2952     if (!dv) oom("sinterCommand");
2953     for (j = 0; j < setsnum; j++) {
2954         robj *setobj;
2955
2956         setobj = dstkey ?
2957                     lookupKeyWrite(c->db,setskeys[j]) :
2958                     lookupKeyRead(c->db,setskeys[j]);
2959         if (!setobj) {
2960             zfree(dv);
2961             if (dstkey) {
2962                 deleteKey(c->db,dstkey);
2963                 addReply(c,shared.ok);
2964             } else {
2965                 addReply(c,shared.nullmultibulk);
2966             }
2967             return;
2968         }
2969         if (setobj->type != REDIS_SET) {
2970             zfree(dv);
2971             addReply(c,shared.wrongtypeerr);
2972             return;
2973         }
2974         dv[j] = setobj->ptr;
2975     }
2976     /* Sort sets from the smallest to largest, this will improve our
2977      * algorithm's performace */
2978     qsort(dv,setsnum,sizeof(dict*),qsortCompareSetsByCardinality);
2979
2980     /* The first thing we should output is the total number of elements...
2981      * since this is a multi-bulk write, but at this stage we don't know
2982      * the intersection set size, so we use a trick, append an empty object
2983      * to the output list and save the pointer to later modify it with the
2984      * right length */
2985     if (!dstkey) {
2986         lenobj = createObject(REDIS_STRING,NULL);
2987         addReply(c,lenobj);
2988         decrRefCount(lenobj);
2989     } else {
2990         /* If we have a target key where to store the resulting set
2991          * create this key with an empty set inside */
2992         dstset = createSetObject();
2993         deleteKey(c->db,dstkey);
2994         dictAdd(c->db->dict,dstkey,dstset);
2995         incrRefCount(dstkey);
2996     }
2997
2998     /* Iterate all the elements of the first (smallest) set, and test
2999      * the element against all the other sets, if at least one set does
3000      * not include the element it is discarded */
3001     di = dictGetIterator(dv[0]);
3002     if (!di) oom("dictGetIterator");
3003
3004     while((de = dictNext(di)) != NULL) {
3005         robj *ele;
3006
3007         for (j = 1; j < setsnum; j++)
3008             if (dictFind(dv[j],dictGetEntryKey(de)) == NULL) break;
3009         if (j != setsnum)
3010             continue; /* at least one set does not contain the member */
3011         ele = dictGetEntryKey(de);
3012         if (!dstkey) {
3013             addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",sdslen(ele->ptr)));
3014             addReply(c,ele);
3015             addReply(c,shared.crlf);
3016             cardinality++;
3017         } else {
3018             dictAdd(dstset->ptr,ele,NULL);
3019             incrRefCount(ele);
3020         }
3021     }
3022     dictReleaseIterator(di);
3023
3024     if (!dstkey) {
3025         lenobj->ptr = sdscatprintf(sdsempty(),"*%d\r\n",cardinality);
3026     } else {
3027         addReply(c,shared.ok);
3028         server.dirty++;
3029     }
3030     zfree(dv);
3031 }
3032
3033 static void sinterCommand(redisClient *c) {
3034     sinterGenericCommand(c,c->argv+1,c->argc-1,NULL);
3035 }
3036
3037 static void sinterstoreCommand(redisClient *c) {
3038     sinterGenericCommand(c,c->argv+2,c->argc-2,c->argv[1]);
3039 }
3040
3041 static void sunionGenericCommand(redisClient *c, robj **setskeys, int setsnum, robj *dstkey) {
3042     dict **dv = zmalloc(sizeof(dict*)*setsnum);
3043     dictIterator *di;
3044     dictEntry *de;
3045     robj *lenobj = NULL, *dstset = NULL;
3046     int j, cardinality = 0;
3047
3048     if (!dv) oom("sunionCommand");
3049     for (j = 0; j < setsnum; j++) {
3050         robj *setobj;
3051
3052         setobj = dstkey ?
3053                     lookupKeyWrite(c->db,setskeys[j]) :
3054                     lookupKeyRead(c->db,setskeys[j]);
3055         if (!setobj) {
3056             dv[j] = NULL;
3057             continue;
3058         }
3059         if (setobj->type != REDIS_SET) {
3060             zfree(dv);
3061             addReply(c,shared.wrongtypeerr);
3062             return;
3063         }
3064         dv[j] = setobj->ptr;
3065     }
3066
3067     /* We need a temp set object to store our union. If the dstkey
3068      * is not NULL (that is, we are inside an SUNIONSTORE operation) then
3069      * this set object will be the resulting object to set into the target key*/
3070     dstset = createSetObject();
3071
3072     /* The first thing we should output is the total number of elements...
3073      * since this is a multi-bulk write, but at this stage we don't know
3074      * the intersection set size, so we use a trick, append an empty object
3075      * to the output list and save the pointer to later modify it with the
3076      * right length */
3077     if (!dstkey) {
3078         lenobj = createObject(REDIS_STRING,NULL);
3079         addReply(c,lenobj);
3080         decrRefCount(lenobj);
3081     } else {
3082         /* If we have a target key where to store the resulting set
3083          * create this key with an empty set inside */
3084         deleteKey(c->db,dstkey);
3085         dictAdd(c->db->dict,dstkey,dstset);
3086         incrRefCount(dstkey);
3087         server.dirty++;
3088     }
3089
3090     /* Iterate all the elements of all the sets, add every element a single
3091      * time to the result set */
3092     for (j = 0; j < setsnum; j++) {
3093         if (!dv[j]) continue; /* non existing keys are like empty sets */
3094
3095         di = dictGetIterator(dv[j]);
3096         if (!di) oom("dictGetIterator");
3097
3098         while((de = dictNext(di)) != NULL) {
3099             robj *ele;
3100
3101             /* dictAdd will not add the same element multiple times */
3102             ele = dictGetEntryKey(de);
3103             if (dictAdd(dstset->ptr,ele,NULL) == DICT_OK) {
3104                 incrRefCount(ele);
3105                 if (!dstkey) {
3106                     addReplySds(c,sdscatprintf(sdsempty(),
3107                             "$%d\r\n",sdslen(ele->ptr)));
3108                     addReply(c,ele);
3109                     addReply(c,shared.crlf);
3110                     cardinality++;
3111                 }
3112             }
3113         }
3114         dictReleaseIterator(di);
3115     }
3116
3117     if (!dstkey) {
3118         lenobj->ptr = sdscatprintf(sdsempty(),"*%d\r\n",cardinality);
3119         decrRefCount(dstset);
3120     } else {
3121         addReply(c,shared.ok);
3122         server.dirty++;
3123     }
3124     zfree(dv);
3125 }
3126
3127 static void sunionCommand(redisClient *c) {
3128     sunionGenericCommand(c,c->argv+1,c->argc-1,NULL);
3129 }
3130
3131 static void sunionstoreCommand(redisClient *c) {
3132     sunionGenericCommand(c,c->argv+2,c->argc-2,c->argv[1]);
3133 }
3134
3135 static void flushdbCommand(redisClient *c) {
3136     server.dirty += dictSize(c->db->dict);
3137     dictEmpty(c->db->dict);
3138     dictEmpty(c->db->expires);
3139     addReply(c,shared.ok);
3140 }
3141
3142 static void flushallCommand(redisClient *c) {
3143     server.dirty += emptyDb();
3144     addReply(c,shared.ok);
3145     rdbSave(server.dbfilename);
3146     server.dirty++;
3147 }
3148
3149 redisSortOperation *createSortOperation(int type, robj *pattern) {
3150     redisSortOperation *so = zmalloc(sizeof(*so));
3151     if (!so) oom("createSortOperation");
3152     so->type = type;
3153     so->pattern = pattern;
3154     return so;
3155 }
3156
3157 /* Return the value associated to the key with a name obtained
3158  * substituting the first occurence of '*' in 'pattern' with 'subst' */
3159 robj *lookupKeyByPattern(redisDb *db, robj *pattern, robj *subst) {
3160     char *p;
3161     sds spat, ssub;
3162     robj keyobj;
3163     int prefixlen, sublen, postfixlen;
3164     /* Expoit the internal sds representation to create a sds string allocated on the stack in order to make this function faster */
3165     struct {
3166         long len;
3167         long free;
3168         char buf[REDIS_SORTKEY_MAX+1];
3169     } keyname;
3170
3171     spat = pattern->ptr;
3172     ssub = subst->ptr;
3173     if (sdslen(spat)+sdslen(ssub)-1 > REDIS_SORTKEY_MAX) return NULL;
3174     p = strchr(spat,'*');
3175     if (!p) return NULL;
3176
3177     prefixlen = p-spat;
3178     sublen = sdslen(ssub);
3179     postfixlen = sdslen(spat)-(prefixlen+1);
3180     memcpy(keyname.buf,spat,prefixlen);
3181     memcpy(keyname.buf+prefixlen,ssub,sublen);
3182     memcpy(keyname.buf+prefixlen+sublen,p+1,postfixlen);
3183     keyname.buf[prefixlen+sublen+postfixlen] = '\0';
3184     keyname.len = prefixlen+sublen+postfixlen;
3185
3186     keyobj.refcount = 1;
3187     keyobj.type = REDIS_STRING;
3188     keyobj.ptr = ((char*)&keyname)+(sizeof(long)*2);
3189
3190     /* printf("lookup '%s' => %p\n", keyname.buf,de); */
3191     return lookupKeyRead(db,&keyobj);
3192 }
3193
3194 /* sortCompare() is used by qsort in sortCommand(). Given that qsort_r with
3195  * the additional parameter is not standard but a BSD-specific we have to
3196  * pass sorting parameters via the global 'server' structure */
3197 static int sortCompare(const void *s1, const void *s2) {
3198     const redisSortObject *so1 = s1, *so2 = s2;
3199     int cmp;
3200
3201     if (!server.sort_alpha) {
3202         /* Numeric sorting. Here it's trivial as we precomputed scores */
3203         if (so1->u.score > so2->u.score) {
3204             cmp = 1;
3205         } else if (so1->u.score < so2->u.score) {
3206             cmp = -1;
3207         } else {
3208             cmp = 0;
3209         }
3210     } else {
3211         /* Alphanumeric sorting */
3212         if (server.sort_bypattern) {
3213             if (!so1->u.cmpobj || !so2->u.cmpobj) {
3214                 /* At least one compare object is NULL */
3215                 if (so1->u.cmpobj == so2->u.cmpobj)
3216                     cmp = 0;
3217                 else if (so1->u.cmpobj == NULL)
3218                     cmp = -1;
3219                 else
3220                     cmp = 1;
3221             } else {
3222                 /* We have both the objects, use strcoll */
3223                 cmp = strcoll(so1->u.cmpobj->ptr,so2->u.cmpobj->ptr);
3224             }
3225         } else {
3226             /* Compare elements directly */
3227             cmp = strcoll(so1->obj->ptr,so2->obj->ptr);
3228         }
3229     }
3230     return server.sort_desc ? -cmp : cmp;
3231 }
3232
3233 /* The SORT command is the most complex command in Redis. Warning: this code
3234  * is optimized for speed and a bit less for readability */
3235 static void sortCommand(redisClient *c) {
3236     list *operations;
3237     int outputlen = 0;
3238     int desc = 0, alpha = 0;
3239     int limit_start = 0, limit_count = -1, start, end;
3240     int j, dontsort = 0, vectorlen;
3241     int getop = 0; /* GET operation counter */
3242     robj *sortval, *sortby = NULL;
3243     redisSortObject *vector; /* Resulting vector to sort */
3244
3245     /* Lookup the key to sort. It must be of the right types */
3246     sortval = lookupKeyRead(c->db,c->argv[1]);
3247     if (sortval == NULL) {
3248         addReply(c,shared.nokeyerr);
3249         return;
3250     }
3251     if (sortval->type != REDIS_SET && sortval->type != REDIS_LIST) {
3252         addReply(c,shared.wrongtypeerr);
3253         return;
3254     }
3255
3256     /* Create a list of operations to perform for every sorted element.
3257      * Operations can be GET/DEL/INCR/DECR */
3258     operations = listCreate();
3259     listSetFreeMethod(operations,zfree);
3260     j = 2;
3261
3262     /* Now we need to protect sortval incrementing its count, in the future
3263      * SORT may have options able to overwrite/delete keys during the sorting
3264      * and the sorted key itself may get destroied */
3265     incrRefCount(sortval);
3266
3267     /* The SORT command has an SQL-alike syntax, parse it */
3268     while(j < c->argc) {
3269         int leftargs = c->argc-j-1;
3270         if (!strcasecmp(c->argv[j]->ptr,"asc")) {
3271             desc = 0;
3272         } else if (!strcasecmp(c->argv[j]->ptr,"desc")) {
3273             desc = 1;
3274         } else if (!strcasecmp(c->argv[j]->ptr,"alpha")) {
3275             alpha = 1;
3276         } else if (!strcasecmp(c->argv[j]->ptr,"limit") && leftargs >= 2) {
3277             limit_start = atoi(c->argv[j+1]->ptr);
3278             limit_count = atoi(c->argv[j+2]->ptr);
3279             j+=2;
3280         } else if (!strcasecmp(c->argv[j]->ptr,"by") && leftargs >= 1) {
3281             sortby = c->argv[j+1];
3282             /* If the BY pattern does not contain '*', i.e. it is constant,
3283              * we don't need to sort nor to lookup the weight keys. */
3284             if (strchr(c->argv[j+1]->ptr,'*') == NULL) dontsort = 1;
3285             j++;
3286         } else if (!strcasecmp(c->argv[j]->ptr,"get") && leftargs >= 1) {
3287             listAddNodeTail(operations,createSortOperation(
3288                 REDIS_SORT_GET,c->argv[j+1]));
3289             getop++;
3290             j++;
3291         } else if (!strcasecmp(c->argv[j]->ptr,"del") && leftargs >= 1) {
3292             listAddNodeTail(operations,createSortOperation(
3293                 REDIS_SORT_DEL,c->argv[j+1]));
3294             j++;
3295         } else if (!strcasecmp(c->argv[j]->ptr,"incr") && leftargs >= 1) {
3296             listAddNodeTail(operations,createSortOperation(
3297                 REDIS_SORT_INCR,c->argv[j+1]));
3298             j++;
3299         } else if (!strcasecmp(c->argv[j]->ptr,"get") && leftargs >= 1) {
3300             listAddNodeTail(operations,createSortOperation(
3301                 REDIS_SORT_DECR,c->argv[j+1]));
3302             j++;
3303         } else {
3304             decrRefCount(sortval);
3305             listRelease(operations);
3306             addReply(c,shared.syntaxerr);
3307             return;
3308         }
3309         j++;
3310     }
3311
3312     /* Load the sorting vector with all the objects to sort */
3313     vectorlen = (sortval->type == REDIS_LIST) ?
3314         listLength((list*)sortval->ptr) :
3315         dictSize((dict*)sortval->ptr);
3316     vector = zmalloc(sizeof(redisSortObject)*vectorlen);
3317     if (!vector) oom("allocating objects vector for SORT");
3318     j = 0;
3319     if (sortval->type == REDIS_LIST) {
3320         list *list = sortval->ptr;
3321         listNode *ln;
3322
3323         listRewind(list);
3324         while((ln = listYield(list))) {
3325             robj *ele = ln->value;
3326             vector[j].obj = ele;
3327             vector[j].u.score = 0;
3328             vector[j].u.cmpobj = NULL;
3329             j++;
3330         }
3331     } else {
3332         dict *set = sortval->ptr;
3333         dictIterator *di;
3334         dictEntry *setele;
3335
3336         di = dictGetIterator(set);
3337         if (!di) oom("dictGetIterator");
3338         while((setele = dictNext(di)) != NULL) {
3339             vector[j].obj = dictGetEntryKey(setele);
3340             vector[j].u.score = 0;
3341             vector[j].u.cmpobj = NULL;
3342             j++;
3343         }
3344         dictReleaseIterator(di);
3345     }
3346     assert(j == vectorlen);
3347
3348     /* Now it's time to load the right scores in the sorting vector */
3349     if (dontsort == 0) {
3350         for (j = 0; j < vectorlen; j++) {
3351             if (sortby) {
3352                 robj *byval;
3353
3354                 byval = lookupKeyByPattern(c->db,sortby,vector[j].obj);
3355                 if (!byval || byval->type != REDIS_STRING) continue;
3356                 if (alpha) {
3357                     vector[j].u.cmpobj = byval;
3358                     incrRefCount(byval);
3359                 } else {
3360                     vector[j].u.score = strtod(byval->ptr,NULL);
3361                 }
3362             } else {
3363                 if (!alpha) vector[j].u.score = strtod(vector[j].obj->ptr,NULL);
3364             }
3365         }
3366     }
3367
3368     /* We are ready to sort the vector... perform a bit of sanity check
3369      * on the LIMIT option too. We'll use a partial version of quicksort. */
3370     start = (limit_start < 0) ? 0 : limit_start;
3371     end = (limit_count < 0) ? vectorlen-1 : start+limit_count-1;
3372     if (start >= vectorlen) {
3373         start = vectorlen-1;
3374         end = vectorlen-2;
3375     }
3376     if (end >= vectorlen) end = vectorlen-1;
3377
3378     if (dontsort == 0) {
3379         server.sort_desc = desc;
3380         server.sort_alpha = alpha;
3381         server.sort_bypattern = sortby ? 1 : 0;
3382         qsort(vector,vectorlen,sizeof(redisSortObject),sortCompare);
3383     }
3384
3385     /* Send command output to the output buffer, performing the specified
3386      * GET/DEL/INCR/DECR operations if any. */
3387     outputlen = getop ? getop*(end-start+1) : end-start+1;
3388     addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",outputlen));
3389     for (j = start; j <= end; j++) {
3390         listNode *ln;
3391         if (!getop) {
3392             addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",
3393                 sdslen(vector[j].obj->ptr)));
3394             addReply(c,vector[j].obj);
3395             addReply(c,shared.crlf);
3396         }
3397         listRewind(operations);
3398         while((ln = listYield(operations))) {
3399             redisSortOperation *sop = ln->value;
3400             robj *val = lookupKeyByPattern(c->db,sop->pattern,
3401                 vector[j].obj);
3402
3403             if (sop->type == REDIS_SORT_GET) {
3404                 if (!val || val->type != REDIS_STRING) {
3405                     addReply(c,shared.nullbulk);
3406                 } else {
3407                     addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",
3408                         sdslen(val->ptr)));
3409                     addReply(c,val);
3410                     addReply(c,shared.crlf);
3411                 }
3412             } else if (sop->type == REDIS_SORT_DEL) {
3413                 /* TODO */
3414             }
3415         }
3416     }
3417
3418     /* Cleanup */
3419     decrRefCount(sortval);
3420     listRelease(operations);
3421     for (j = 0; j < vectorlen; j++) {
3422         if (sortby && alpha && vector[j].u.cmpobj)
3423             decrRefCount(vector[j].u.cmpobj);
3424     }
3425     zfree(vector);
3426 }
3427
3428 static void infoCommand(redisClient *c) {
3429     sds info;
3430     time_t uptime = time(NULL)-server.stat_starttime;
3431
3432     info = sdscatprintf(sdsempty(),
3433         "redis_version:%s\r\n"
3434         "connected_clients:%d\r\n"
3435         "connected_slaves:%d\r\n"
3436         "used_memory:%zu\r\n"
3437         "changes_since_last_save:%lld\r\n"
3438         "bgsave_in_progress:%d\r\n"
3439         "last_save_time:%d\r\n"
3440         "total_connections_received:%lld\r\n"
3441         "total_commands_processed:%lld\r\n"
3442         "uptime_in_seconds:%d\r\n"
3443         "uptime_in_days:%d\r\n"
3444         ,REDIS_VERSION,
3445         listLength(server.clients)-listLength(server.slaves),
3446         listLength(server.slaves),
3447         server.usedmemory,
3448         server.dirty,
3449         server.bgsaveinprogress,
3450         server.lastsave,
3451         server.stat_numconnections,
3452         server.stat_numcommands,
3453         uptime,
3454         uptime/(3600*24)
3455     );
3456     addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",sdslen(info)));
3457     addReplySds(c,info);
3458     addReply(c,shared.crlf);
3459 }
3460
3461 static void monitorCommand(redisClient *c) {
3462     /* ignore MONITOR if aleady slave or in monitor mode */
3463     if (c->flags & REDIS_SLAVE) return;
3464
3465     c->flags |= (REDIS_SLAVE|REDIS_MONITOR);
3466     c->slaveseldb = 0;
3467     if (!listAddNodeTail(server.monitors,c)) oom("listAddNodeTail");
3468     addReply(c,shared.ok);
3469 }
3470
3471 /* ================================= Expire ================================= */
3472 static int removeExpire(redisDb *db, robj *key) {
3473     if (dictDelete(db->expires,key) == DICT_OK) {
3474         return 1;
3475     } else {
3476         return 0;
3477     }
3478 }
3479
3480 static int setExpire(redisDb *db, robj *key, time_t when) {
3481     if (dictAdd(db->expires,key,(void*)when) == DICT_ERR) {
3482         return 0;
3483     } else {
3484         incrRefCount(key);
3485         return 1;
3486     }
3487 }
3488
3489 /* Return the expire time of the specified key, or -1 if no expire
3490  * is associated with this key (i.e. the key is non volatile) */
3491 static time_t getExpire(redisDb *db, robj *key) {
3492     dictEntry *de;
3493
3494     /* No expire? return ASAP */
3495     if (dictSize(db->expires) == 0 ||
3496        (de = dictFind(db->expires,key)) == NULL) return -1;
3497
3498     return (time_t) dictGetEntryVal(de);
3499 }
3500
3501 static int expireIfNeeded(redisDb *db, robj *key) {
3502     time_t when;
3503     dictEntry *de;
3504
3505     /* No expire? return ASAP */
3506     if (dictSize(db->expires) == 0 ||
3507        (de = dictFind(db->expires,key)) == NULL) return 0;
3508
3509     /* Lookup the expire */
3510     when = (time_t) dictGetEntryVal(de);
3511     if (time(NULL) <= when) return 0;
3512
3513     /* Delete the key */
3514     dictDelete(db->expires,key);
3515     return dictDelete(db->dict,key) == DICT_OK;
3516 }
3517
3518 static int deleteIfVolatile(redisDb *db, robj *key) {
3519     dictEntry *de;
3520
3521     /* No expire? return ASAP */
3522     if (dictSize(db->expires) == 0 ||
3523        (de = dictFind(db->expires,key)) == NULL) return 0;
3524
3525     /* Delete the key */
3526     server.dirty++;
3527     dictDelete(db->expires,key);
3528     return dictDelete(db->dict,key) == DICT_OK;
3529 }
3530
3531 static void expireCommand(redisClient *c) {
3532     dictEntry *de;
3533     int seconds = atoi(c->argv[2]->ptr);
3534
3535     de = dictFind(c->db->dict,c->argv[1]);
3536     if (de == NULL) {
3537         addReply(c,shared.czero);
3538         return;
3539     }
3540     if (seconds <= 0) {
3541         addReply(c, shared.czero);
3542         return;
3543     } else {
3544         time_t when = time(NULL)+seconds;
3545         if (setExpire(c->db,c->argv[1],when))
3546             addReply(c,shared.cone);
3547         else
3548             addReply(c,shared.czero);
3549         return;
3550     }
3551 }
3552
3553 /* =============================== Replication  ============================= */
3554
3555 static int syncWrite(int fd, char *ptr, ssize_t size, int timeout) {
3556     ssize_t nwritten, ret = size;
3557     time_t start = time(NULL);
3558
3559     timeout++;
3560     while(size) {
3561         if (aeWait(fd,AE_WRITABLE,1000) & AE_WRITABLE) {
3562             nwritten = write(fd,ptr,size);
3563             if (nwritten == -1) return -1;
3564             ptr += nwritten;
3565             size -= nwritten;
3566         }
3567         if ((time(NULL)-start) > timeout) {
3568             errno = ETIMEDOUT;
3569             return -1;
3570         }
3571     }
3572     return ret;
3573 }
3574
3575 static int syncRead(int fd, char *ptr, ssize_t size, int timeout) {
3576     ssize_t nread, totread = 0;
3577     time_t start = time(NULL);
3578
3579     timeout++;
3580     while(size) {
3581         if (aeWait(fd,AE_READABLE,1000) & AE_READABLE) {
3582             nread = read(fd,ptr,size);
3583             if (nread == -1) return -1;
3584             ptr += nread;
3585             size -= nread;
3586             totread += nread;
3587         }
3588         if ((time(NULL)-start) > timeout) {
3589             errno = ETIMEDOUT;
3590             return -1;
3591         }
3592     }
3593     return totread;
3594 }
3595
3596 static int syncReadLine(int fd, char *ptr, ssize_t size, int timeout) {
3597     ssize_t nread = 0;
3598
3599     size--;
3600     while(size) {
3601         char c;
3602
3603         if (syncRead(fd,&c,1,timeout) == -1) return -1;
3604         if (c == '\n') {
3605             *ptr = '\0';
3606             if (nread && *(ptr-1) == '\r') *(ptr-1) = '\0';
3607             return nread;
3608         } else {
3609             *ptr++ = c;
3610             *ptr = '\0';
3611             nread++;
3612         }
3613     }
3614     return nread;
3615 }
3616
3617 static void syncCommand(redisClient *c) {
3618     /* ignore SYNC if aleady slave or in monitor mode */
3619     if (c->flags & REDIS_SLAVE) return;
3620
3621     /* SYNC can't be issued when the server has pending data to send to
3622      * the client about already issued commands. We need a fresh reply
3623      * buffer registering the differences between the BGSAVE and the current
3624      * dataset, so that we can copy to other slaves if needed. */
3625     if (listLength(c->reply) != 0) {
3626         addReplySds(c,sdsnew("-ERR SYNC is invalid with pending input\r\n"));
3627         return;
3628     }
3629
3630     redisLog(REDIS_NOTICE,"Slave ask for synchronization");
3631     /* Here we need to check if there is a background saving operation
3632      * in progress, or if it is required to start one */
3633     if (server.bgsaveinprogress) {
3634         /* Ok a background save is in progress. Let's check if it is a good
3635          * one for replication, i.e. if there is another slave that is
3636          * registering differences since the server forked to save */
3637         redisClient *slave;
3638         listNode *ln;
3639
3640         listRewind(server.slaves);
3641         while((ln = listYield(server.slaves))) {
3642             slave = ln->value;
3643             if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_END) break;
3644         }
3645         if (ln) {
3646             /* Perfect, the server is already registering differences for
3647              * another slave. Set the right state, and copy the buffer. */
3648             listRelease(c->reply);
3649             c->reply = listDup(slave->reply);
3650             if (!c->reply) oom("listDup copying slave reply list");
3651             c->replstate = REDIS_REPL_WAIT_BGSAVE_END;
3652             redisLog(REDIS_NOTICE,"Waiting for end of BGSAVE for SYNC");
3653         } else {
3654             /* No way, we need to wait for the next BGSAVE in order to
3655              * register differences */
3656             c->replstate = REDIS_REPL_WAIT_BGSAVE_START;
3657             redisLog(REDIS_NOTICE,"Waiting for next BGSAVE for SYNC");
3658         }
3659     } else {
3660         /* Ok we don't have a BGSAVE in progress, let's start one */
3661         redisLog(REDIS_NOTICE,"Starting BGSAVE for SYNC");
3662         if (rdbSaveBackground(server.dbfilename) != REDIS_OK) {
3663             redisLog(REDIS_NOTICE,"Replication failed, can't BGSAVE");
3664             addReplySds(c,sdsnew("-ERR Unalbe to perform background save\r\n"));
3665             return;
3666         }
3667         c->replstate = REDIS_REPL_WAIT_BGSAVE_END;
3668     }
3669     c->repldbfd = -1;
3670     c->flags |= REDIS_SLAVE;
3671     c->slaveseldb = 0;
3672     if (!listAddNodeTail(server.slaves,c)) oom("listAddNodeTail");
3673     return;
3674 }
3675
3676 static void sendBulkToSlave(aeEventLoop *el, int fd, void *privdata, int mask) {
3677     redisClient *slave = privdata;
3678     REDIS_NOTUSED(el);
3679     REDIS_NOTUSED(mask);
3680     char buf[REDIS_IOBUF_LEN];
3681     ssize_t nwritten, buflen;
3682
3683     if (slave->repldboff == 0) {
3684         /* Write the bulk write count before to transfer the DB. In theory here
3685          * we don't know how much room there is in the output buffer of the
3686          * socket, but in pratice SO_SNDLOWAT (the minimum count for output
3687          * operations) will never be smaller than the few bytes we need. */
3688         sds bulkcount;
3689
3690         bulkcount = sdscatprintf(sdsempty(),"$%lld\r\n",(unsigned long long)
3691             slave->repldbsize);
3692         if (write(fd,bulkcount,sdslen(bulkcount)) != (signed)sdslen(bulkcount))
3693         {
3694             sdsfree(bulkcount);
3695             freeClient(slave);
3696             return;
3697         }
3698         sdsfree(bulkcount);
3699     }
3700     lseek(slave->repldbfd,slave->repldboff,SEEK_SET);
3701     buflen = read(slave->repldbfd,buf,REDIS_IOBUF_LEN);
3702     if (buflen <= 0) {
3703         redisLog(REDIS_WARNING,"Read error sending DB to slave: %s",
3704             (buflen == 0) ? "premature EOF" : strerror(errno));
3705         freeClient(slave);
3706         return;
3707     }
3708     if ((nwritten = write(fd,buf,buflen)) == -1) {
3709         redisLog(REDIS_DEBUG,"Write error sending DB to slave: %s",
3710             strerror(errno));
3711         freeClient(slave);
3712         return;
3713     }
3714     slave->repldboff += nwritten;
3715     if (slave->repldboff == slave->repldbsize) {
3716         close(slave->repldbfd);
3717         slave->repldbfd = -1;
3718         aeDeleteFileEvent(server.el,slave->fd,AE_WRITABLE);
3719         slave->replstate = REDIS_REPL_ONLINE;
3720         if (aeCreateFileEvent(server.el, slave->fd, AE_WRITABLE,
3721             sendReplyToClient, slave, NULL) == AE_ERR) {
3722             freeClient(slave);
3723             return;
3724         }
3725         addReplySds(slave,sdsempty());
3726         redisLog(REDIS_NOTICE,"Synchronization with slave succeeded");
3727     }
3728 }
3729
3730 static void updateSalvesWaitingBgsave(int bgsaveerr) {
3731     listNode *ln;
3732     int startbgsave = 0;
3733
3734     listRewind(server.slaves);
3735     while((ln = listYield(server.slaves))) {
3736         redisClient *slave = ln->value;
3737
3738         if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_START) {
3739             startbgsave = 1;
3740             slave->replstate = REDIS_REPL_WAIT_BGSAVE_END;
3741         } else if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_END) {
3742             struct stat buf;
3743
3744             if (bgsaveerr != REDIS_OK) {
3745                 freeClient(slave);
3746                 redisLog(REDIS_WARNING,"SYNC failed. BGSAVE child returned an error");
3747                 continue;
3748             }
3749             if ((slave->repldbfd = open(server.dbfilename,O_RDONLY)) == -1 ||
3750                 fstat(slave->repldbfd,&buf) == -1) {
3751                 freeClient(slave);
3752                 redisLog(REDIS_WARNING,"SYNC failed. Can't open/stat DB after BGSAVE: %s", strerror(errno));
3753                 continue;
3754             }
3755             slave->repldboff = 0;
3756             slave->repldbsize = buf.st_size;
3757             slave->replstate = REDIS_REPL_SEND_BULK;
3758             aeDeleteFileEvent(server.el,slave->fd,AE_WRITABLE);
3759             if (aeCreateFileEvent(server.el, slave->fd, AE_WRITABLE, sendBulkToSlave, slave, NULL) == AE_ERR) {
3760                 freeClient(slave);
3761                 continue;
3762             }
3763         }
3764     }
3765     if (startbgsave) {
3766         if (rdbSaveBackground(server.dbfilename) != REDIS_OK) {
3767             listRewind(server.slaves);
3768             redisLog(REDIS_WARNING,"SYNC failed. BGSAVE failed");
3769             while((ln = listYield(server.slaves))) {
3770                 redisClient *slave = ln->value;
3771
3772                 if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_START)
3773                     freeClient(slave);
3774             }
3775         }
3776     }
3777 }
3778
3779 static int syncWithMaster(void) {
3780     char buf[1024], tmpfile[256];
3781     int dumpsize;
3782     int fd = anetTcpConnect(NULL,server.masterhost,server.masterport);
3783     int dfd;
3784
3785     if (fd == -1) {
3786         redisLog(REDIS_WARNING,"Unable to connect to MASTER: %s",
3787             strerror(errno));
3788         return REDIS_ERR;
3789     }
3790     /* Issue the SYNC command */
3791     if (syncWrite(fd,"SYNC \r\n",7,5) == -1) {
3792         close(fd);
3793         redisLog(REDIS_WARNING,"I/O error writing to MASTER: %s",
3794             strerror(errno));
3795         return REDIS_ERR;
3796     }
3797     /* Read the bulk write count */
3798     if (syncReadLine(fd,buf,1024,5) == -1) {
3799         close(fd);
3800         redisLog(REDIS_WARNING,"I/O error reading bulk count from MASTER: %s",
3801             strerror(errno));
3802         return REDIS_ERR;
3803     }
3804     dumpsize = atoi(buf+1);
3805     redisLog(REDIS_NOTICE,"Receiving %d bytes data dump from MASTER",dumpsize);
3806     /* Read the bulk write data on a temp file */
3807     snprintf(tmpfile,256,"temp-%d.%ld.rdb",(int)time(NULL),(long int)random());
3808     dfd = open(tmpfile,O_CREAT|O_WRONLY,0644);
3809     if (dfd == -1) {
3810         close(fd);
3811         redisLog(REDIS_WARNING,"Opening the temp file needed for MASTER <-> SLAVE synchronization: %s",strerror(errno));
3812         return REDIS_ERR;
3813     }
3814     while(dumpsize) {
3815         int nread, nwritten;
3816
3817         nread = read(fd,buf,(dumpsize < 1024)?dumpsize:1024);
3818         if (nread == -1) {
3819             redisLog(REDIS_WARNING,"I/O error trying to sync with MASTER: %s",
3820                 strerror(errno));
3821             close(fd);
3822             close(dfd);
3823             return REDIS_ERR;
3824         }
3825         nwritten = write(dfd,buf,nread);
3826         if (nwritten == -1) {
3827             redisLog(REDIS_WARNING,"Write error writing to the DB dump file needed for MASTER <-> SLAVE synchrnonization: %s", strerror(errno));
3828             close(fd);
3829             close(dfd);
3830             return REDIS_ERR;
3831         }
3832         dumpsize -= nread;
3833     }
3834     close(dfd);
3835     if (rename(tmpfile,server.dbfilename) == -1) {
3836         redisLog(REDIS_WARNING,"Failed trying to rename the temp DB into dump.rdb in MASTER <-> SLAVE synchronization: %s", strerror(errno));
3837         unlink(tmpfile);
3838         close(fd);
3839         return REDIS_ERR;
3840     }
3841     emptyDb();
3842     if (rdbLoad(server.dbfilename) != REDIS_OK) {
3843         redisLog(REDIS_WARNING,"Failed trying to load the MASTER synchronization DB from disk");
3844         close(fd);
3845         return REDIS_ERR;
3846     }
3847     server.master = createClient(fd);
3848     server.master->flags |= REDIS_MASTER;
3849     server.replstate = REDIS_REPL_CONNECTED;
3850     return REDIS_OK;
3851 }
3852
3853 /* =================================== Main! ================================ */
3854
3855 #ifdef __linux__
3856 int linuxOvercommitMemoryValue(void) {
3857     FILE *fp = fopen("/proc/sys/vm/overcommit_memory","r");
3858     char buf[64];
3859
3860     if (!fp) return -1;
3861     if (fgets(buf,64,fp) == NULL) {
3862         fclose(fp);
3863         return -1;
3864     }
3865     fclose(fp);
3866
3867     return atoi(buf);
3868 }
3869
3870 void linuxOvercommitMemoryWarning(void) {
3871     if (linuxOvercommitMemoryValue() == 0) {
3872         redisLog(REDIS_WARNING,"WARNING overcommit_memory is set to 0! Background save may fail under low condition memory. To fix this issue add 'echo 1 > /proc/sys/vm/overcommit_memory' in your init scripts.");
3873     }
3874 }
3875 #endif /* __linux__ */
3876
3877 static void daemonize(void) {
3878     int fd;
3879     FILE *fp;
3880
3881     if (fork() != 0) exit(0); /* parent exits */
3882     setsid(); /* create a new session */
3883
3884     /* Every output goes to /dev/null. If Redis is daemonized but
3885      * the 'logfile' is set to 'stdout' in the configuration file
3886      * it will not log at all. */
3887     if ((fd = open("/dev/null", O_RDWR, 0)) != -1) {
3888         dup2(fd, STDIN_FILENO);
3889         dup2(fd, STDOUT_FILENO);
3890         dup2(fd, STDERR_FILENO);
3891         if (fd > STDERR_FILENO) close(fd);
3892     }
3893     /* Try to write the pid file */
3894     fp = fopen(server.pidfile,"w");
3895     if (fp) {
3896         fprintf(fp,"%d\n",getpid());
3897         fclose(fp);
3898     }
3899 }
3900
3901 int main(int argc, char **argv) {
3902 #ifdef __linux__
3903     linuxOvercommitMemoryWarning();
3904 #endif
3905
3906     initServerConfig();
3907     if (argc == 2) {
3908         ResetServerSaveParams();
3909         loadServerConfig(argv[1]);
3910     } else if (argc > 2) {
3911         fprintf(stderr,"Usage: ./redis-server [/path/to/redis.conf]\n");
3912         exit(1);
3913     }
3914     initServer();
3915     if (server.daemonize) daemonize();
3916     redisLog(REDIS_NOTICE,"Server started, Redis version " REDIS_VERSION);
3917     if (rdbLoad(server.dbfilename) == REDIS_OK)
3918         redisLog(REDIS_NOTICE,"DB loaded from disk");
3919     if (aeCreateFileEvent(server.el, server.fd, AE_READABLE,
3920         acceptHandler, NULL, NULL) == AE_ERR) oom("creating file event");
3921     redisLog(REDIS_NOTICE,"The server is now ready to accept connections on port %d", server.port);
3922     aeMain(server.el);
3923     aeDeleteEventLoop(server.el);
3924     return 0;
3925 }