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"    /* LZF compression library */
  60 #include "pqsort.h" /* Partial qsort for SORT+LIMIT */
  61
  62 /* Error codes */
  63 #define REDIS_OK                0
  64 #define REDIS_ERR               -1
  65
  66 /* Static server configuration */
  67 #define REDIS_SERVERPORT        6379    /* TCP port */
  68 #define REDIS_MAXIDLETIME       (60*5)  /* default client timeout */
  69 #define REDIS_IOBUF_LEN         1024
  70 #define REDIS_LOADBUF_LEN       1024
  71 #define REDIS_STATIC_ARGS       4
  72 #define REDIS_DEFAULT_DBNUM     16
  73 #define REDIS_CONFIGLINE_MAX    1024
  74 #define REDIS_OBJFREELIST_MAX   1000000 /* Max number of objects to cache */
  75 #define REDIS_MAX_SYNC_TIME     60      /* Slave can't take more to sync */
  76 #define REDIS_EXPIRELOOKUPS_PER_CRON    100 /* try to expire 100 keys/second */
  77
  78 /* Hash table parameters */
  79 #define REDIS_HT_MINFILL        10      /* Minimal hash table fill 10% */
  80 #define REDIS_HT_MINSLOTS       16384   /* Never resize the HT under this */
  81
  82 /* Command flags */
  83 #define REDIS_CMD_BULK          1
  84 #define REDIS_CMD_INLINE        2
  85
  86 /* Object types */
  87 #define REDIS_STRING 0
  88 #define REDIS_LIST 1
  89 #define REDIS_SET 2
  90 #define REDIS_HASH 3
  91
  92 /* Object types only used for dumping to disk */
  93 #define REDIS_EXPIRETIME 253
  94 #define REDIS_SELECTDB 254
  95 #define REDIS_EOF 255
  96
  97 /* Defines related to the dump file format. To store 32 bits lengths for short
  98  * keys requires a lot of space, so we check the most significant 2 bits of
  99  * the first byte to interpreter the length:
 100  *
 101  * 00|000000 => if the two MSB are 00 the len is the 6 bits of this byte
 102  * 01|000000 00000000 =>  01, the len is 14 byes, 6 bits + 8 bits of next byte
 103  * 10|000000 [32 bit integer] => if it's 01, a full 32 bit len will follow
 104  * 11|000000 this means: specially encoded object will follow. The six bits
 105  *           number specify the kind of object that follows.
 106  *           See the REDIS_RDB_ENC_* defines.
 107  *
 108  * Lenghts up to 63 are stored using a single byte, most DB keys, and may
 109  * values, will fit inside. */
 110 #define REDIS_RDB_6BITLEN 0
 111 #define REDIS_RDB_14BITLEN 1
 112 #define REDIS_RDB_32BITLEN 2
 113 #define REDIS_RDB_ENCVAL 3
 114 #define REDIS_RDB_LENERR UINT_MAX
 115
 116 /* When a length of a string object stored on disk has the first two bits
 117  * set, the remaining two bits specify a special encoding for the object
 118  * accordingly to the following defines: */
 119 #define REDIS_RDB_ENC_INT8 0        /* 8 bit signed integer */
 120 #define REDIS_RDB_ENC_INT16 1       /* 16 bit signed integer */
 121 #define REDIS_RDB_ENC_INT32 2       /* 32 bit signed integer */
 122 #define REDIS_RDB_ENC_LZF 3         /* string compressed with FASTLZ */
 123
 124 /* Client flags */
 125 #define REDIS_CLOSE 1       /* This client connection should be closed ASAP */
 126 #define REDIS_SLAVE 2       /* This client is a slave server */
 127 #define REDIS_MASTER 4      /* This client is a master server */
 128 #define REDIS_MONITOR 8      /* This client is a slave monitor, see MONITOR */
 129
 130 /* Slave replication state - slave side */
 131 #define REDIS_REPL_NONE 0   /* No active replication */
 132 #define REDIS_REPL_CONNECT 1    /* Must connect to master */
 133 #define REDIS_REPL_CONNECTED 2  /* Connected to master */
 134
 135 /* Slave replication state - from the point of view of master
 136  * Note that in SEND_BULK and ONLINE state the slave receives new updates
 137  * in its output queue. In the WAIT_BGSAVE state instead the server is waiting
 138  * to start the next background saving in order to send updates to it. */
 139 #define REDIS_REPL_WAIT_BGSAVE_START 3 /* master waits bgsave to start feeding it */
 140 #define REDIS_REPL_WAIT_BGSAVE_END 4 /* master waits bgsave to start bulk DB transmission */
 141 #define REDIS_REPL_SEND_BULK 5 /* master is sending the bulk DB */
 142 #define REDIS_REPL_ONLINE 6 /* bulk DB already transmitted, receive updates */
 143
 144 /* List related stuff */
 145 #define REDIS_HEAD 0
 146 #define REDIS_TAIL 1
 147
 148 /* Sort operations */
 149 #define REDIS_SORT_GET 0
 150 #define REDIS_SORT_DEL 1
 151 #define REDIS_SORT_INCR 2
 152 #define REDIS_SORT_DECR 3
 153 #define REDIS_SORT_ASC 4
 154 #define REDIS_SORT_DESC 5
 155 #define REDIS_SORTKEY_MAX 1024
 156
 157 /* Log levels */
 158 #define REDIS_DEBUG 0
 159 #define REDIS_NOTICE 1
 160 #define REDIS_WARNING 2
 161
 162 /* Anti-warning macro... */
 163 #define REDIS_NOTUSED(V) ((void) V)
 164
 165 /*================================= Data types ============================== */
 166
 167 /* A redis object, that is a type able to hold a string / list / set */
 168 typedef struct redisObject {
 169     void *ptr;
 170     int type;
 171     int refcount;
 172 } robj;
 173
 174 typedef struct redisDb {
 175     dict *dict;
 176     dict *expires;
 177     int id;
 178 } redisDb;
 179
 180 /* With multiplexing we need to take per-clinet state.
 181  * Clients are taken in a liked list. */
 182 typedef struct redisClient {
 183     int fd;
 184     redisDb *db;
 185     int dictid;
 186     sds querybuf;
 187     robj **argv;
 188     int argc;
 189     int bulklen;            /* bulk read len. -1 if not in bulk read mode */
 190     list *reply;
 191     int sentlen;
 192     time_t lastinteraction; /* time of the last interaction, used for timeout */
 193     int flags;              /* REDIS_CLOSE | REDIS_SLAVE | REDIS_MONITOR */
 194     int slaveseldb;         /* slave selected db, if this client is a slave */
 195     int authenticated;      /* when requirepass is non-NULL */
 196     int replstate;          /* replication state if this is a slave */
 197     int repldbfd;           /* replication DB file descriptor */
 198     long repldboff;          /* replication DB file offset */
 199     off_t repldbsize;       /* replication DB file size */
 200 } redisClient;
 201
 202 struct saveparam {
 203     time_t seconds;
 204     int changes;
 205 };
 206
 207 /* Global server state structure */
 208 struct redisServer {
 209     int port;
 210     int fd;
 211     redisDb *db;
 212     dict *sharingpool;
 213     unsigned int sharingpoolsize;
 214     long long dirty;            /* changes to DB from the last save */
 215     list *clients;
 216     list *slaves, *monitors;
 217     char neterr[ANET_ERR_LEN];
 218     aeEventLoop *el;
 219     int cronloops;              /* number of times the cron function run */
 220     list *objfreelist;          /* A list of freed objects to avoid malloc() */
 221     time_t lastsave;            /* Unix time of last save succeeede */
 222     size_t usedmemory;             /* Used memory in megabytes */
 223     /* Fields used only for stats */
 224     time_t stat_starttime;         /* server start time */
 225     long long stat_numcommands;    /* number of processed commands */
 226     long long stat_numconnections; /* number of connections received */
 227     /* Configuration */
 228     int verbosity;
 229     int glueoutputbuf;
 230     int maxidletime;
 231     int dbnum;
 232     int daemonize;
 233     char *pidfile;
 234     int bgsaveinprogress;
 235     struct saveparam *saveparams;
 236     int saveparamslen;
 237     char *logfile;
 238     char *bindaddr;
 239     char *dbfilename;
 240     char *requirepass;
 241     int shareobjects;
 242     /* Replication related */
 243     int isslave;
 244     char *masterhost;
 245     int masterport;
 246     redisClient *master;    /* client that is master for this slave */
 247     int replstate;
 248     /* Sort parameters - qsort_r() is only available under BSD so we
 249      * have to take this state global, in order to pass it to sortCompare() */
 250     int sort_desc;
 251     int sort_alpha;
 252     int sort_bypattern;
 253 };
 254
 255 typedef void redisCommandProc(redisClient *c);
 256 struct redisCommand {
 257     char *name;
 258     redisCommandProc *proc;
 259     int arity;
 260     int flags;
 261 };
 262
 263 typedef struct _redisSortObject {
 264     robj *obj;
 265     union {
 266         double score;
 267         robj *cmpobj;
 268     } u;
 269 } redisSortObject;
 270
 271 typedef struct _redisSortOperation {
 272     int type;
 273     robj *pattern;
 274 } redisSortOperation;
 275
 276 struct sharedObjectsStruct {
 277     robj *crlf, *ok, *err, *emptybulk, *czero, *cone, *pong, *space,
 278     *colon, *nullbulk, *nullmultibulk,
 279     *emptymultibulk, *wrongtypeerr, *nokeyerr, *syntaxerr, *sameobjecterr,
 280     *outofrangeerr, *plus,
 281     *select0, *select1, *select2, *select3, *select4,
 282     *select5, *select6, *select7, *select8, *select9;
 283 } shared;
 284
 285 /*================================ Prototypes =============================== */
 286
 287 static void freeStringObject(robj *o);
 288 static void freeListObject(robj *o);
 289 static void freeSetObject(robj *o);
 290 static void decrRefCount(void *o);
 291 static robj *createObject(int type, void *ptr);
 292 static void freeClient(redisClient *c);
 293 static int rdbLoad(char *filename);
 294 static void addReply(redisClient *c, robj *obj);
 295 static void addReplySds(redisClient *c, sds s);
 296 static void incrRefCount(robj *o);
 297 static int rdbSaveBackground(char *filename);
 298 static robj *createStringObject(char *ptr, size_t len);
 299 static void replicationFeedSlaves(list *slaves, struct redisCommand *cmd, int dictid, robj **argv, int argc);
 300 static int syncWithMaster(void);
 301 static robj *tryObjectSharing(robj *o);
 302 static int removeExpire(redisDb *db, robj *key);
 303 static int expireIfNeeded(redisDb *db, robj *key);
 304 static int deleteIfVolatile(redisDb *db, robj *key);
 305 static int deleteKey(redisDb *db, robj *key);
 306 static time_t getExpire(redisDb *db, robj *key);
 307 static int setExpire(redisDb *db, robj *key, time_t when);
 308 static void updateSalvesWaitingBgsave(int bgsaveerr);
 309
 310 static void authCommand(redisClient *c);
 311 static void pingCommand(redisClient *c);
 312 static void echoCommand(redisClient *c);
 313 static void setCommand(redisClient *c);
 314 static void setnxCommand(redisClient *c);
 315 static void getCommand(redisClient *c);
 316 static void delCommand(redisClient *c);
 317 static void existsCommand(redisClient *c);
 318 static void incrCommand(redisClient *c);
 319 static void decrCommand(redisClient *c);
 320 static void incrbyCommand(redisClient *c);
 321 static void decrbyCommand(redisClient *c);
 322 static void selectCommand(redisClient *c);
 323 static void randomkeyCommand(redisClient *c);
 324 static void keysCommand(redisClient *c);
 325 static void dbsizeCommand(redisClient *c);
 326 static void lastsaveCommand(redisClient *c);
 327 static void saveCommand(redisClient *c);
 328 static void bgsaveCommand(redisClient *c);
 329 static void shutdownCommand(redisClient *c);
 330 static void moveCommand(redisClient *c);
 331 static void renameCommand(redisClient *c);
 332 static void renamenxCommand(redisClient *c);
 333 static void lpushCommand(redisClient *c);
 334 static void rpushCommand(redisClient *c);
 335 static void lpopCommand(redisClient *c);
 336 static void rpopCommand(redisClient *c);
 337 static void llenCommand(redisClient *c);
 338 static void lindexCommand(redisClient *c);
 339 static void lrangeCommand(redisClient *c);
 340 static void ltrimCommand(redisClient *c);
 341 static void typeCommand(redisClient *c);
 342 static void lsetCommand(redisClient *c);
 343 static void saddCommand(redisClient *c);
 344 static void sremCommand(redisClient *c);
 345 static void smoveCommand(redisClient *c);
 346 static void sismemberCommand(redisClient *c);
 347 static void scardCommand(redisClient *c);
 348 static void sinterCommand(redisClient *c);
 349 static void sinterstoreCommand(redisClient *c);
 350 static void sunionCommand(redisClient *c);
 351 static void sunionstoreCommand(redisClient *c);
 352 static void sdiffCommand(redisClient *c);
 353 static void sdiffstoreCommand(redisClient *c);
 354 static void syncCommand(redisClient *c);
 355 static void flushdbCommand(redisClient *c);
 356 static void flushallCommand(redisClient *c);
 357 static void sortCommand(redisClient *c);
 358 static void lremCommand(redisClient *c);
 359 static void infoCommand(redisClient *c);
 360 static void mgetCommand(redisClient *c);
 361 static void monitorCommand(redisClient *c);
 362 static void expireCommand(redisClient *c);
 363 static void getSetCommand(redisClient *c);
 364
 365 /*================================= Globals ================================= */
 366
 367 /* Global vars */
 368 static struct redisServer server; /* server global state */
 369 static struct redisCommand cmdTable[] = {
 370     {"get",getCommand,2,REDIS_CMD_INLINE},
 371     {"set",setCommand,3,REDIS_CMD_BULK},
 372     {"setnx",setnxCommand,3,REDIS_CMD_BULK},
 373     {"del",delCommand,-2,REDIS_CMD_INLINE},
 374     {"exists",existsCommand,2,REDIS_CMD_INLINE},
 375     {"incr",incrCommand,2,REDIS_CMD_INLINE},
 376     {"decr",decrCommand,2,REDIS_CMD_INLINE},
 377     {"mget",mgetCommand,-2,REDIS_CMD_INLINE},
 378     {"rpush",rpushCommand,3,REDIS_CMD_BULK},
 379     {"lpush",lpushCommand,3,REDIS_CMD_BULK},
 380     {"rpop",rpopCommand,2,REDIS_CMD_INLINE},
 381     {"lpop",lpopCommand,2,REDIS_CMD_INLINE},
 382     {"llen",llenCommand,2,REDIS_CMD_INLINE},
 383     {"lindex",lindexCommand,3,REDIS_CMD_INLINE},
 384     {"lset",lsetCommand,4,REDIS_CMD_BULK},
 385     {"lrange",lrangeCommand,4,REDIS_CMD_INLINE},
 386     {"ltrim",ltrimCommand,4,REDIS_CMD_INLINE},
 387     {"lrem",lremCommand,4,REDIS_CMD_BULK},
 388     {"sadd",saddCommand,3,REDIS_CMD_BULK},
 389     {"srem",sremCommand,3,REDIS_CMD_BULK},
 390     {"smove",smoveCommand,4,REDIS_CMD_BULK},
 391     {"sismember",sismemberCommand,3,REDIS_CMD_BULK},
 392     {"scard",scardCommand,2,REDIS_CMD_INLINE},
 393     {"sinter",sinterCommand,-2,REDIS_CMD_INLINE},
 394     {"sinterstore",sinterstoreCommand,-3,REDIS_CMD_INLINE},
 395     {"sunion",sunionCommand,-2,REDIS_CMD_INLINE},
 396     {"sunionstore",sunionstoreCommand,-3,REDIS_CMD_INLINE},
 397     {"sdiff",sdiffCommand,-2,REDIS_CMD_INLINE},
 398     {"sdiffstore",sdiffstoreCommand,-3,REDIS_CMD_INLINE},
 399     {"smembers",sinterCommand,2,REDIS_CMD_INLINE},
 400     {"incrby",incrbyCommand,3,REDIS_CMD_INLINE},
 401     {"decrby",decrbyCommand,3,REDIS_CMD_INLINE},
 402     {"getset",getSetCommand,3,REDIS_CMD_BULK},
 403     {"randomkey",randomkeyCommand,1,REDIS_CMD_INLINE},
 404     {"select",selectCommand,2,REDIS_CMD_INLINE},
 405     {"move",moveCommand,3,REDIS_CMD_INLINE},
 406     {"rename",renameCommand,3,REDIS_CMD_INLINE},
 407     {"renamenx",renamenxCommand,3,REDIS_CMD_INLINE},
 408     {"keys",keysCommand,2,REDIS_CMD_INLINE},
 409     {"dbsize",dbsizeCommand,1,REDIS_CMD_INLINE},
 410     {"auth",authCommand,2,REDIS_CMD_INLINE},
 411     {"ping",pingCommand,1,REDIS_CMD_INLINE},
 412     {"echo",echoCommand,2,REDIS_CMD_BULK},
 413     {"save",saveCommand,1,REDIS_CMD_INLINE},
 414     {"bgsave",bgsaveCommand,1,REDIS_CMD_INLINE},
 415     {"shutdown",shutdownCommand,1,REDIS_CMD_INLINE},
 416     {"lastsave",lastsaveCommand,1,REDIS_CMD_INLINE},
 417     {"type",typeCommand,2,REDIS_CMD_INLINE},
 418     {"sync",syncCommand,1,REDIS_CMD_INLINE},
 419     {"flushdb",flushdbCommand,1,REDIS_CMD_INLINE},
 420     {"flushall",flushallCommand,1,REDIS_CMD_INLINE},
 421     {"sort",sortCommand,-2,REDIS_CMD_INLINE},
 422     {"info",infoCommand,1,REDIS_CMD_INLINE},
 423     {"monitor",monitorCommand,1,REDIS_CMD_INLINE},
 424     {"expire",expireCommand,3,REDIS_CMD_INLINE},
 425     {NULL,NULL,0,0}
 426 };
 427
 428 /*============================ Utility functions ============================ */
 429
 430 /* Glob-style pattern matching. */
 431 int stringmatchlen(const char *pattern, int patternLen,
 432         const char *string, int stringLen, int nocase)
 433 {
 434     while(patternLen) {
 435         switch(pattern[0]) {
 436         case '*':
 437             while (pattern[1] == '*') {
 438                 pattern++;
 439                 patternLen--;
 440             }
 441             if (patternLen == 1)
 442                 return 1; /* match */
 443             while(stringLen) {
 444                 if (stringmatchlen(pattern+1, patternLen-1,
 445                             string, stringLen, nocase))
 446                     return 1; /* match */
 447                 string++;
 448                 stringLen--;
 449             }
 450             return 0; /* no match */
 451             break;
 452         case '?':
 453             if (stringLen == 0)
 454                 return 0; /* no match */
 455             string++;
 456             stringLen--;
 457             break;
 458         case '[':
 459         {
 460             int not, match;
 461
 462             pattern++;
 463             patternLen--;
 464             not = pattern[0] == '^';
 465             if (not) {
 466                 pattern++;
 467                 patternLen--;
 468             }
 469             match = 0;
 470             while(1) {
 471                 if (pattern[0] == '\\') {
 472                     pattern++;
 473                     patternLen--;
 474                     if (pattern[0] == string[0])
 475                         match = 1;
 476                 } else if (pattern[0] == ']') {
 477                     break;
 478                 } else if (patternLen == 0) {
 479                     pattern--;
 480                     patternLen++;
 481                     break;
 482                 } else if (pattern[1] == '-' && patternLen >= 3) {
 483                     int start = pattern[0];
 484                     int end = pattern[2];
 485                     int c = string[0];
 486                     if (start > end) {
 487                         int t = start;
 488                         start = end;
 489                         end = t;
 490                     }
 491                     if (nocase) {
 492                         start = tolower(start);
 493                         end = tolower(end);
 494                         c = tolower(c);
 495                     }
 496                     pattern += 2;
 497                     patternLen -= 2;
 498                     if (c >= start && c <= end)
 499                         match = 1;
 500                 } else {
 501                     if (!nocase) {
 502                         if (pattern[0] == string[0])
 503                             match = 1;
 504                     } else {
 505                         if (tolower((int)pattern[0]) == tolower((int)string[0]))
 506                             match = 1;
 507                     }
 508                 }
 509                 pattern++;
 510                 patternLen--;
 511             }
 512             if (not)
 513                 match = !match;
 514             if (!match)
 515                 return 0; /* no match */
 516             string++;
 517             stringLen--;
 518             break;
 519         }
 520         case '\\':
 521             if (patternLen >= 2) {
 522                 pattern++;
 523                 patternLen--;
 524             }
 525             /* fall through */
 526         default:
 527             if (!nocase) {
 528                 if (pattern[0] != string[0])
 529                     return 0; /* no match */
 530             } else {
 531                 if (tolower((int)pattern[0]) != tolower((int)string[0]))
 532                     return 0; /* no match */
 533             }
 534             string++;
 535             stringLen--;
 536             break;
 537         }
 538         pattern++;
 539         patternLen--;
 540         if (stringLen == 0) {
 541             while(*pattern == '*') {
 542                 pattern++;
 543                 patternLen--;
 544             }
 545             break;
 546         }
 547     }
 548     if (patternLen == 0 && stringLen == 0)
 549         return 1;
 550     return 0;
 551 }
 552
 553 void redisLog(int level, const char *fmt, ...)
 554 {
 555     va_list ap;
 556     FILE *fp;
 557
 558     fp = (server.logfile == NULL) ? stdout : fopen(server.logfile,"a");
 559     if (!fp) return;
 560
 561     va_start(ap, fmt);
 562     if (level >= server.verbosity) {
 563         char *c = ".-*";
 564         char buf[64];
 565         time_t now;
 566
 567         now = time(NULL);
 568         strftime(buf,64,"%d %b %H:%M:%S",gmtime(&now));
 569         fprintf(fp,"%s %c ",buf,c[level]);
 570         vfprintf(fp, fmt, ap);
 571         fprintf(fp,"\n");
 572         fflush(fp);
 573     }
 574     va_end(ap);
 575
 576     if (server.logfile) fclose(fp);
 577 }
 578
 579 /*====================== Hash table type implementation  ==================== */
 580
 581 /* This is an hash table type that uses the SDS dynamic strings libary as
 582  * keys and radis objects as values (objects can hold SDS strings,
 583  * lists, sets). */
 584
 585 static int sdsDictKeyCompare(void *privdata, const void *key1,
 586         const void *key2)
 587 {
 588     int l1,l2;
 589     DICT_NOTUSED(privdata);
 590
 591     l1 = sdslen((sds)key1);
 592     l2 = sdslen((sds)key2);
 593     if (l1 != l2) return 0;
 594     return memcmp(key1, key2, l1) == 0;
 595 }
 596
 597 static void dictRedisObjectDestructor(void *privdata, void *val)
 598 {
 599     DICT_NOTUSED(privdata);
 600
 601     decrRefCount(val);
 602 }
 603
 604 static int dictSdsKeyCompare(void *privdata, const void *key1,
 605         const void *key2)
 606 {
 607     const robj *o1 = key1, *o2 = key2;
 608     return sdsDictKeyCompare(privdata,o1->ptr,o2->ptr);
 609 }
 610
 611 static unsigned int dictSdsHash(const void *key) {
 612     const robj *o = key;
 613     return dictGenHashFunction(o->ptr, sdslen((sds)o->ptr));
 614 }
 615
 616 static dictType setDictType = {
 617     dictSdsHash,               /* hash function */
 618     NULL,                      /* key dup */
 619     NULL,                      /* val dup */
 620     dictSdsKeyCompare,         /* key compare */
 621     dictRedisObjectDestructor, /* key destructor */
 622     NULL                       /* val destructor */
 623 };
 624
 625 static dictType hashDictType = {
 626     dictSdsHash,                /* hash function */
 627     NULL,                       /* key dup */
 628     NULL,                       /* val dup */
 629     dictSdsKeyCompare,          /* key compare */
 630     dictRedisObjectDestructor,  /* key destructor */
 631     dictRedisObjectDestructor   /* val destructor */
 632 };
 633
 634 /* ========================= Random utility functions ======================= */
 635
 636 /* Redis generally does not try to recover from out of memory conditions
 637  * when allocating objects or strings, it is not clear if it will be possible
 638  * to report this condition to the client since the networking layer itself
 639  * is based on heap allocation for send buffers, so we simply abort.
 640  * At least the code will be simpler to read... */
 641 static void oom(const char *msg) {
 642     fprintf(stderr, "%s: Out of memory\n",msg);
 643     fflush(stderr);
 644     sleep(1);
 645     abort();
 646 }
 647
 648 /* ====================== Redis server networking stuff ===================== */
 649 void closeTimedoutClients(void) {
 650     redisClient *c;
 651     listNode *ln;
 652     time_t now = time(NULL);
 653
 654     listRewind(server.clients);
 655     while ((ln = listYield(server.clients)) != NULL) {
 656         c = listNodeValue(ln);
 657         if (!(c->flags & REDIS_SLAVE) &&    /* no timeout for slaves */
 658              (now - c->lastinteraction > server.maxidletime)) {
 659             redisLog(REDIS_DEBUG,"Closing idle client");
 660             freeClient(c);
 661         }
 662     }
 663 }
 664
 665 /* If the percentage of used slots in the HT reaches REDIS_HT_MINFILL
 666  * we resize the hash table to save memory */
 667 void tryResizeHashTables(void) {
 668     int j;
 669
 670     for (j = 0; j < server.dbnum; j++) {
 671         long long size, used;
 672
 673         size = dictSlots(server.db[j].dict);
 674         used = dictSize(server.db[j].dict);
 675         if (size && used && size > REDIS_HT_MINSLOTS &&
 676             (used*100/size < REDIS_HT_MINFILL)) {
 677             redisLog(REDIS_NOTICE,"The hash table %d is too sparse, resize it...",j);
 678             dictResize(server.db[j].dict);
 679             redisLog(REDIS_NOTICE,"Hash table %d resized.",j);
 680         }
 681     }
 682 }
 683
 684 int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
 685     int j, loops = server.cronloops++;
 686     REDIS_NOTUSED(eventLoop);
 687     REDIS_NOTUSED(id);
 688     REDIS_NOTUSED(clientData);
 689
 690     /* Update the global state with the amount of used memory */
 691     server.usedmemory = zmalloc_used_memory();
 692
 693     /* Show some info about non-empty databases */
 694     for (j = 0; j < server.dbnum; j++) {
 695         long long size, used, vkeys;
 696
 697         size = dictSlots(server.db[j].dict);
 698         used = dictSize(server.db[j].dict);
 699         vkeys = dictSize(server.db[j].expires);
 700         if (!(loops % 5) && used > 0) {
 701             redisLog(REDIS_DEBUG,"DB %d: %d keys (%d volatile) in %d slots HT.",j,used,vkeys,size);
 702             /* dictPrintStats(server.dict); */
 703         }
 704     }
 705
 706     /* We don't want to resize the hash tables while a bacground saving
 707      * is in progress: the saving child is created using fork() that is
 708      * implemented with a copy-on-write semantic in most modern systems, so
 709      * if we resize the HT while there is the saving child at work actually
 710      * a lot of memory movements in the parent will cause a lot of pages
 711      * copied. */
 712     if (!server.bgsaveinprogress) tryResizeHashTables();
 713
 714     /* Show information about connected clients */
 715     if (!(loops % 5)) {
 716         redisLog(REDIS_DEBUG,"%d clients connected (%d slaves), %zu bytes in use",
 717             listLength(server.clients)-listLength(server.slaves),
 718             listLength(server.slaves),
 719             server.usedmemory,
 720             dictSize(server.sharingpool));
 721     }
 722
 723     /* Close connections of timedout clients */
 724     if (server.maxidletime && !(loops % 10))
 725         closeTimedoutClients();
 726
 727     /* Check if a background saving in progress terminated */
 728     if (server.bgsaveinprogress) {
 729         int statloc;
 730         /* XXX: TODO handle the case of the saving child killed */
 731         if (wait4(-1,&statloc,WNOHANG,NULL)) {
 732             int exitcode = WEXITSTATUS(statloc);
 733             if (exitcode == 0) {
 734                 redisLog(REDIS_NOTICE,
 735                     "Background saving terminated with success");
 736                 server.dirty = 0;
 737                 server.lastsave = time(NULL);
 738             } else {
 739                 redisLog(REDIS_WARNING,
 740                     "Background saving error");
 741             }
 742             server.bgsaveinprogress = 0;
 743             updateSalvesWaitingBgsave(exitcode == 0 ? REDIS_OK : REDIS_ERR);
 744         }
 745     } else {
 746         /* If there is not a background saving in progress check if
 747          * we have to save now */
 748          time_t now = time(NULL);
 749          for (j = 0; j < server.saveparamslen; j++) {
 750             struct saveparam *sp = server.saveparams+j;
 751
 752             if (server.dirty >= sp->changes &&
 753                 now-server.lastsave > sp->seconds) {
 754                 redisLog(REDIS_NOTICE,"%d changes in %d seconds. Saving...",
 755                     sp->changes, sp->seconds);
 756                 rdbSaveBackground(server.dbfilename);
 757                 break;
 758             }
 759          }
 760     }
 761
 762     /* Try to expire a few timed out keys */
 763     for (j = 0; j < server.dbnum; j++) {
 764         redisDb *db = server.db+j;
 765         int num = dictSize(db->expires);
 766
 767         if (num) {
 768             time_t now = time(NULL);
 769
 770             if (num > REDIS_EXPIRELOOKUPS_PER_CRON)
 771                 num = REDIS_EXPIRELOOKUPS_PER_CRON;
 772             while (num--) {
 773                 dictEntry *de;
 774                 time_t t;
 775
 776                 if ((de = dictGetRandomKey(db->expires)) == NULL) break;
 777                 t = (time_t) dictGetEntryVal(de);
 778                 if (now > t) {
 779                     deleteKey(db,dictGetEntryKey(de));
 780                 }
 781             }
 782         }
 783     }
 784
 785     /* Check if we should connect to a MASTER */
 786     if (server.replstate == REDIS_REPL_CONNECT) {
 787         redisLog(REDIS_NOTICE,"Connecting to MASTER...");
 788         if (syncWithMaster() == REDIS_OK) {
 789             redisLog(REDIS_NOTICE,"MASTER <-> SLAVE sync succeeded");
 790         }
 791     }
 792     return 1000;
 793 }
 794
 795 static void createSharedObjects(void) {
 796     shared.crlf = createObject(REDIS_STRING,sdsnew("\r\n"));
 797     shared.ok = createObject(REDIS_STRING,sdsnew("+OK\r\n"));
 798     shared.err = createObject(REDIS_STRING,sdsnew("-ERR\r\n"));
 799     shared.emptybulk = createObject(REDIS_STRING,sdsnew("$0\r\n\r\n"));
 800     shared.czero = createObject(REDIS_STRING,sdsnew(":0\r\n"));
 801     shared.cone = createObject(REDIS_STRING,sdsnew(":1\r\n"));
 802     shared.nullbulk = createObject(REDIS_STRING,sdsnew("$-1\r\n"));
 803     shared.nullmultibulk = createObject(REDIS_STRING,sdsnew("*-1\r\n"));
 804     shared.emptymultibulk = createObject(REDIS_STRING,sdsnew("*0\r\n"));
 805     /* no such key */
 806     shared.pong = createObject(REDIS_STRING,sdsnew("+PONG\r\n"));
 807     shared.wrongtypeerr = createObject(REDIS_STRING,sdsnew(
 808         "-ERR Operation against a key holding the wrong kind of value\r\n"));
 809     shared.nokeyerr = createObject(REDIS_STRING,sdsnew(
 810         "-ERR no such key\r\n"));
 811     shared.syntaxerr = createObject(REDIS_STRING,sdsnew(
 812         "-ERR syntax error\r\n"));
 813     shared.sameobjecterr = createObject(REDIS_STRING,sdsnew(
 814         "-ERR source and destination objects are the same\r\n"));
 815     shared.outofrangeerr = createObject(REDIS_STRING,sdsnew(
 816         "-ERR index out of range\r\n"));
 817     shared.space = createObject(REDIS_STRING,sdsnew(" "));
 818     shared.colon = createObject(REDIS_STRING,sdsnew(":"));
 819     shared.plus = createObject(REDIS_STRING,sdsnew("+"));
 820     shared.select0 = createStringObject("select 0\r\n",10);
 821     shared.select1 = createStringObject("select 1\r\n",10);
 822     shared.select2 = createStringObject("select 2\r\n",10);
 823     shared.select3 = createStringObject("select 3\r\n",10);
 824     shared.select4 = createStringObject("select 4\r\n",10);
 825     shared.select5 = createStringObject("select 5\r\n",10);
 826     shared.select6 = createStringObject("select 6\r\n",10);
 827     shared.select7 = createStringObject("select 7\r\n",10);
 828     shared.select8 = createStringObject("select 8\r\n",10);
 829     shared.select9 = createStringObject("select 9\r\n",10);
 830 }
 831
 832 static void appendServerSaveParams(time_t seconds, int changes) {
 833     server.saveparams = zrealloc(server.saveparams,sizeof(struct saveparam)*(server.saveparamslen+1));
 834     if (server.saveparams == NULL) oom("appendServerSaveParams");
 835     server.saveparams[server.saveparamslen].seconds = seconds;
 836     server.saveparams[server.saveparamslen].changes = changes;
 837     server.saveparamslen++;
 838 }
 839
 840 static void ResetServerSaveParams() {
 841     zfree(server.saveparams);
 842     server.saveparams = NULL;
 843     server.saveparamslen = 0;
 844 }
 845
 846 static void initServerConfig() {
 847     server.dbnum = REDIS_DEFAULT_DBNUM;
 848     server.port = REDIS_SERVERPORT;
 849     server.verbosity = REDIS_DEBUG;
 850     server.maxidletime = REDIS_MAXIDLETIME;
 851     server.saveparams = NULL;
 852     server.logfile = NULL; /* NULL = log on standard output */
 853     server.bindaddr = NULL;
 854     server.glueoutputbuf = 1;
 855     server.daemonize = 0;
 856     server.pidfile = "/var/run/redis.pid";
 857     server.dbfilename = "dump.rdb";
 858     server.requirepass = NULL;
 859     server.shareobjects = 0;
 860     ResetServerSaveParams();
 861
 862     appendServerSaveParams(60*60,1);  /* save after 1 hour and 1 change */
 863     appendServerSaveParams(300,100);  /* save after 5 minutes and 100 changes */
 864     appendServerSaveParams(60,10000); /* save after 1 minute and 10000 changes */
 865     /* Replication related */
 866     server.isslave = 0;
 867     server.masterhost = NULL;
 868     server.masterport = 6379;
 869     server.master = NULL;
 870     server.replstate = REDIS_REPL_NONE;
 871 }
 872
 873 static void initServer() {
 874     int j;
 875
 876     signal(SIGHUP, SIG_IGN);
 877     signal(SIGPIPE, SIG_IGN);
 878
 879     server.clients = listCreate();
 880     server.slaves = listCreate();
 881     server.monitors = listCreate();
 882     server.objfreelist = listCreate();
 883     createSharedObjects();
 884     server.el = aeCreateEventLoop();
 885     server.db = zmalloc(sizeof(redisDb)*server.dbnum);
 886     server.sharingpool = dictCreate(&setDictType,NULL);
 887     server.sharingpoolsize = 1024;
 888     if (!server.db || !server.clients || !server.slaves || !server.monitors || !server.el || !server.objfreelist)
 889         oom("server initialization"); /* Fatal OOM */
 890     server.fd = anetTcpServer(server.neterr, server.port, server.bindaddr);
 891     if (server.fd == -1) {
 892         redisLog(REDIS_WARNING, "Opening TCP port: %s", server.neterr);
 893         exit(1);
 894     }
 895     for (j = 0; j < server.dbnum; j++) {
 896         server.db[j].dict = dictCreate(&hashDictType,NULL);
 897         server.db[j].expires = dictCreate(&setDictType,NULL);
 898         server.db[j].id = j;
 899     }
 900     server.cronloops = 0;
 901     server.bgsaveinprogress = 0;
 902     server.lastsave = time(NULL);
 903     server.dirty = 0;
 904     server.usedmemory = 0;
 905     server.stat_numcommands = 0;
 906     server.stat_numconnections = 0;
 907     server.stat_starttime = time(NULL);
 908     aeCreateTimeEvent(server.el, 1000, serverCron, NULL, NULL);
 909 }
 910
 911 /* Empty the whole database */
 912 static long long emptyDb() {
 913     int j;
 914     long long removed = 0;
 915
 916     for (j = 0; j < server.dbnum; j++) {
 917         removed += dictSize(server.db[j].dict);
 918         dictEmpty(server.db[j].dict);
 919         dictEmpty(server.db[j].expires);
 920     }
 921     return removed;
 922 }
 923
 924 static int yesnotoi(char *s) {
 925     if (!strcasecmp(s,"yes")) return 1;
 926     else if (!strcasecmp(s,"no")) return 0;
 927     else return -1;
 928 }
 929
 930 /* I agree, this is a very rudimental way to load a configuration...
 931    will improve later if the config gets more complex */
 932 static void loadServerConfig(char *filename) {
 933     FILE *fp = fopen(filename,"r");
 934     char buf[REDIS_CONFIGLINE_MAX+1], *err = NULL;
 935     int linenum = 0;
 936     sds line = NULL;
 937
 938     if (!fp) {
 939         redisLog(REDIS_WARNING,"Fatal error, can't open config file");
 940         exit(1);
 941     }
 942     while(fgets(buf,REDIS_CONFIGLINE_MAX+1,fp) != NULL) {
 943         sds *argv;
 944         int argc, j;
 945
 946         linenum++;
 947         line = sdsnew(buf);
 948         line = sdstrim(line," \t\r\n");
 949
 950         /* Skip comments and blank lines*/
 951         if (line[0] == '#' || line[0] == '\0') {
 952             sdsfree(line);
 953             continue;
 954         }
 955
 956         /* Split into arguments */
 957         argv = sdssplitlen(line,sdslen(line)," ",1,&argc);
 958         sdstolower(argv[0]);
 959
 960         /* Execute config directives */
 961         if (!strcasecmp(argv[0],"timeout") && argc == 2) {
 962             server.maxidletime = atoi(argv[1]);
 963             if (server.maxidletime < 0) {
 964                 err = "Invalid timeout value"; goto loaderr;
 965             }
 966         } else if (!strcasecmp(argv[0],"port") && argc == 2) {
 967             server.port = atoi(argv[1]);
 968             if (server.port < 1 || server.port > 65535) {
 969                 err = "Invalid port"; goto loaderr;
 970             }
 971         } else if (!strcasecmp(argv[0],"bind") && argc == 2) {
 972             server.bindaddr = zstrdup(argv[1]);
 973         } else if (!strcasecmp(argv[0],"save") && argc == 3) {
 974             int seconds = atoi(argv[1]);
 975             int changes = atoi(argv[2]);
 976             if (seconds < 1 || changes < 0) {
 977                 err = "Invalid save parameters"; goto loaderr;
 978             }
 979             appendServerSaveParams(seconds,changes);
 980         } else if (!strcasecmp(argv[0],"dir") && argc == 2) {
 981             if (chdir(argv[1]) == -1) {
 982                 redisLog(REDIS_WARNING,"Can't chdir to '%s': %s",
 983                     argv[1], strerror(errno));
 984                 exit(1);
 985             }
 986         } else if (!strcasecmp(argv[0],"loglevel") && argc == 2) {
 987             if (!strcasecmp(argv[1],"debug")) server.verbosity = REDIS_DEBUG;
 988             else if (!strcasecmp(argv[1],"notice")) server.verbosity = REDIS_NOTICE;
 989             else if (!strcasecmp(argv[1],"warning")) server.verbosity = REDIS_WARNING;
 990             else {
 991                 err = "Invalid log level. Must be one of debug, notice, warning";
 992                 goto loaderr;
 993             }
 994         } else if (!strcasecmp(argv[0],"logfile") && argc == 2) {
 995             FILE *fp;
 996
 997             server.logfile = zstrdup(argv[1]);
 998             if (!strcasecmp(server.logfile,"stdout")) {
 999                 zfree(server.logfile);
1000                 server.logfile = NULL;
1001             }
1002             if (server.logfile) {
1003                 /* Test if we are able to open the file. The server will not
1004                  * be able to abort just for this problem later... */
1005                 fp = fopen(server.logfile,"a");
1006                 if (fp == NULL) {
1007                     err = sdscatprintf(sdsempty(),
1008                         "Can't open the log file: %s", strerror(errno));
1009                     goto loaderr;
1010                 }
1011                 fclose(fp);
1012             }
1013         } else if (!strcasecmp(argv[0],"databases") && argc == 2) {
1014             server.dbnum = atoi(argv[1]);
1015             if (server.dbnum < 1) {
1016                 err = "Invalid number of databases"; goto loaderr;
1017             }
1018         } else if (!strcasecmp(argv[0],"slaveof") && argc == 3) {
1019             server.masterhost = sdsnew(argv[1]);
1020             server.masterport = atoi(argv[2]);
1021             server.replstate = REDIS_REPL_CONNECT;
1022         } else if (!strcasecmp(argv[0],"glueoutputbuf") && argc == 2) {
1023             if ((server.glueoutputbuf = yesnotoi(argv[1])) == -1) {
1024                 err = "argument must be 'yes' or 'no'"; goto loaderr;
1025             }
1026         } else if (!strcasecmp(argv[0],"shareobjects") && argc == 2) {
1027             if ((server.shareobjects = yesnotoi(argv[1])) == -1) {
1028                 err = "argument must be 'yes' or 'no'"; goto loaderr;
1029             }
1030         } else if (!strcasecmp(argv[0],"daemonize") && argc == 2) {
1031             if ((server.daemonize = yesnotoi(argv[1])) == -1) {
1032                 err = "argument must be 'yes' or 'no'"; goto loaderr;
1033             }
1034         } else if (!strcasecmp(argv[0],"requirepass") && argc == 2) {
1035           server.requirepass = zstrdup(argv[1]);
1036         } else if (!strcasecmp(argv[0],"pidfile") && argc == 2) {
1037           server.pidfile = zstrdup(argv[1]);
1038         } else if (!strcasecmp(argv[0],"dbfilename") && argc == 2) {
1039           server.dbfilename = zstrdup(argv[1]);
1040         } else {
1041             err = "Bad directive or wrong number of arguments"; goto loaderr;
1042         }
1043         for (j = 0; j < argc; j++)
1044             sdsfree(argv[j]);
1045         zfree(argv);
1046         sdsfree(line);
1047     }
1048     fclose(fp);
1049     return;
1050
1051 loaderr:
1052     fprintf(stderr, "\n*** FATAL CONFIG FILE ERROR ***\n");
1053     fprintf(stderr, "Reading the configuration file, at line %d\n", linenum);
1054     fprintf(stderr, ">>> '%s'\n", line);
1055     fprintf(stderr, "%s\n", err);
1056     exit(1);
1057 }
1058
1059 static void freeClientArgv(redisClient *c) {
1060     int j;
1061
1062     for (j = 0; j < c->argc; j++)
1063         decrRefCount(c->argv[j]);
1064     c->argc = 0;
1065 }
1066
1067 static void freeClient(redisClient *c) {
1068     listNode *ln;
1069
1070     aeDeleteFileEvent(server.el,c->fd,AE_READABLE);
1071     aeDeleteFileEvent(server.el,c->fd,AE_WRITABLE);
1072     sdsfree(c->querybuf);
1073     listRelease(c->reply);
1074     freeClientArgv(c);
1075     close(c->fd);
1076     ln = listSearchKey(server.clients,c);
1077     assert(ln != NULL);
1078     listDelNode(server.clients,ln);
1079     if (c->flags & REDIS_SLAVE) {
1080         if (c->replstate == REDIS_REPL_SEND_BULK && c->repldbfd != -1)
1081             close(c->repldbfd);
1082         list *l = (c->flags & REDIS_MONITOR) ? server.monitors : server.slaves;
1083         ln = listSearchKey(l,c);
1084         assert(ln != NULL);
1085         listDelNode(l,ln);
1086     }
1087     if (c->flags & REDIS_MASTER) {
1088         server.master = NULL;
1089         server.replstate = REDIS_REPL_CONNECT;
1090     }
1091     zfree(c->argv);
1092     zfree(c);
1093 }
1094
1095 static void glueReplyBuffersIfNeeded(redisClient *c) {
1096     int totlen = 0;
1097     listNode *ln;
1098     robj *o;
1099
1100     listRewind(c->reply);
1101     while((ln = listYield(c->reply))) {
1102         o = ln->value;
1103         totlen += sdslen(o->ptr);
1104         /* This optimization makes more sense if we don't have to copy
1105          * too much data */
1106         if (totlen > 1024) return;
1107     }
1108     if (totlen > 0) {
1109         char buf[1024];
1110         int copylen = 0;
1111
1112         listRewind(c->reply);
1113         while((ln = listYield(c->reply))) {
1114             o = ln->value;
1115             memcpy(buf+copylen,o->ptr,sdslen(o->ptr));
1116             copylen += sdslen(o->ptr);
1117             listDelNode(c->reply,ln);
1118         }
1119         /* Now the output buffer is empty, add the new single element */
1120         addReplySds(c,sdsnewlen(buf,totlen));
1121     }
1122 }
1123
1124 static void sendReplyToClient(aeEventLoop *el, int fd, void *privdata, int mask) {
1125     redisClient *c = privdata;
1126     int nwritten = 0, totwritten = 0, objlen;
1127     robj *o;
1128     REDIS_NOTUSED(el);
1129     REDIS_NOTUSED(mask);
1130
1131     if (server.glueoutputbuf && listLength(c->reply) > 1)
1132         glueReplyBuffersIfNeeded(c);
1133     while(listLength(c->reply)) {
1134         o = listNodeValue(listFirst(c->reply));
1135         objlen = sdslen(o->ptr);
1136
1137         if (objlen == 0) {
1138             listDelNode(c->reply,listFirst(c->reply));
1139             continue;
1140         }
1141
1142         if (c->flags & REDIS_MASTER) {
1143             nwritten = objlen - c->sentlen;
1144         } else {
1145             nwritten = write(fd, ((char*)o->ptr)+c->sentlen, objlen - c->sentlen);
1146             if (nwritten <= 0) break;
1147         }
1148         c->sentlen += nwritten;
1149         totwritten += nwritten;
1150         /* If we fully sent the object on head go to the next one */
1151         if (c->sentlen == objlen) {
1152             listDelNode(c->reply,listFirst(c->reply));
1153             c->sentlen = 0;
1154         }
1155     }
1156     if (nwritten == -1) {
1157         if (errno == EAGAIN) {
1158             nwritten = 0;
1159         } else {
1160             redisLog(REDIS_DEBUG,
1161                 "Error writing to client: %s", strerror(errno));
1162             freeClient(c);
1163             return;
1164         }
1165     }
1166     if (totwritten > 0) c->lastinteraction = time(NULL);
1167     if (listLength(c->reply) == 0) {
1168         c->sentlen = 0;
1169         aeDeleteFileEvent(server.el,c->fd,AE_WRITABLE);
1170     }
1171 }
1172
1173 static struct redisCommand *lookupCommand(char *name) {
1174     int j = 0;
1175     while(cmdTable[j].name != NULL) {
1176         if (!strcasecmp(name,cmdTable[j].name)) return &cmdTable[j];
1177         j++;
1178     }
1179     return NULL;
1180 }
1181
1182 /* resetClient prepare the client to process the next command */
1183 static void resetClient(redisClient *c) {
1184     freeClientArgv(c);
1185     c->bulklen = -1;
1186 }
1187
1188 /* If this function gets called we already read a whole
1189  * command, argments are in the client argv/argc fields.
1190  * processCommand() execute the command or prepare the
1191  * server for a bulk read from the client.
1192  *
1193  * If 1 is returned the client is still alive and valid and
1194  * and other operations can be performed by the caller. Otherwise
1195  * if 0 is returned the client was destroied (i.e. after QUIT). */
1196 static int processCommand(redisClient *c) {
1197     struct redisCommand *cmd;
1198     long long dirty;
1199
1200     /* The QUIT command is handled as a special case. Normal command
1201      * procs are unable to close the client connection safely */
1202     if (!strcasecmp(c->argv[0]->ptr,"quit")) {
1203         freeClient(c);
1204         return 0;
1205     }
1206     cmd = lookupCommand(c->argv[0]->ptr);
1207     if (!cmd) {
1208         addReplySds(c,sdsnew("-ERR unknown command\r\n"));
1209         resetClient(c);
1210         return 1;
1211     } else if ((cmd->arity > 0 && cmd->arity != c->argc) ||
1212                (c->argc < -cmd->arity)) {
1213         addReplySds(c,sdsnew("-ERR wrong number of arguments\r\n"));
1214         resetClient(c);
1215         return 1;
1216     } else if (cmd->flags & REDIS_CMD_BULK && c->bulklen == -1) {
1217         int bulklen = atoi(c->argv[c->argc-1]->ptr);
1218
1219         decrRefCount(c->argv[c->argc-1]);
1220         if (bulklen < 0 || bulklen > 1024*1024*1024) {
1221             c->argc--;
1222             addReplySds(c,sdsnew("-ERR invalid bulk write count\r\n"));
1223             resetClient(c);
1224             return 1;
1225         }
1226         c->argc--;
1227         c->bulklen = bulklen+2; /* add two bytes for CR+LF */
1228         /* It is possible that the bulk read is already in the
1229          * buffer. Check this condition and handle it accordingly */
1230         if ((signed)sdslen(c->querybuf) >= c->bulklen) {
1231             c->argv[c->argc] = createStringObject(c->querybuf,c->bulklen-2);
1232             c->argc++;
1233             c->querybuf = sdsrange(c->querybuf,c->bulklen,-1);
1234         } else {
1235             return 1;
1236         }
1237     }
1238     /* Let's try to share objects on the command arguments vector */
1239     if (server.shareobjects) {
1240         int j;
1241         for(j = 1; j < c->argc; j++)
1242             c->argv[j] = tryObjectSharing(c->argv[j]);
1243     }
1244     /* Check if the user is authenticated */
1245     if (server.requirepass && !c->authenticated && cmd->proc != authCommand) {
1246         addReplySds(c,sdsnew("-ERR operation not permitted\r\n"));
1247         resetClient(c);
1248         return 1;
1249     }
1250
1251     /* Exec the command */
1252     dirty = server.dirty;
1253     cmd->proc(c);
1254     if (server.dirty-dirty != 0 && listLength(server.slaves))
1255         replicationFeedSlaves(server.slaves,cmd,c->db->id,c->argv,c->argc);
1256     if (listLength(server.monitors))
1257         replicationFeedSlaves(server.monitors,cmd,c->db->id,c->argv,c->argc);
1258     server.stat_numcommands++;
1259
1260     /* Prepare the client for the next command */
1261     if (c->flags & REDIS_CLOSE) {
1262         freeClient(c);
1263         return 0;
1264     }
1265     resetClient(c);
1266     return 1;
1267 }
1268
1269 static void replicationFeedSlaves(list *slaves, struct redisCommand *cmd, int dictid, robj **argv, int argc) {
1270     listNode *ln;
1271     int outc = 0, j;
1272     robj **outv;
1273     /* (args*2)+1 is enough room for args, spaces, newlines */
1274     robj *static_outv[REDIS_STATIC_ARGS*2+1];
1275
1276     if (argc <= REDIS_STATIC_ARGS) {
1277         outv = static_outv;
1278     } else {
1279         outv = zmalloc(sizeof(robj*)*(argc*2+1));
1280         if (!outv) oom("replicationFeedSlaves");
1281     }
1282
1283     for (j = 0; j < argc; j++) {
1284         if (j != 0) outv[outc++] = shared.space;
1285         if ((cmd->flags & REDIS_CMD_BULK) && j == argc-1) {
1286             robj *lenobj;
1287
1288             lenobj = createObject(REDIS_STRING,
1289                 sdscatprintf(sdsempty(),"%d\r\n",sdslen(argv[j]->ptr)));
1290             lenobj->refcount = 0;
1291             outv[outc++] = lenobj;
1292         }
1293         outv[outc++] = argv[j];
1294     }
1295     outv[outc++] = shared.crlf;
1296
1297     /* Increment all the refcounts at start and decrement at end in order to
1298      * be sure to free objects if there is no slave in a replication state
1299      * able to be feed with commands */
1300     for (j = 0; j < outc; j++) incrRefCount(outv[j]);
1301     listRewind(slaves);
1302     while((ln = listYield(slaves))) {
1303         redisClient *slave = ln->value;
1304
1305         /* Don't feed slaves that are still waiting for BGSAVE to start */
1306         if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_START) continue;
1307
1308         /* Feed all the other slaves, MONITORs and so on */
1309         if (slave->slaveseldb != dictid) {
1310             robj *selectcmd;
1311
1312             switch(dictid) {
1313             case 0: selectcmd = shared.select0; break;
1314             case 1: selectcmd = shared.select1; break;
1315             case 2: selectcmd = shared.select2; break;
1316             case 3: selectcmd = shared.select3; break;
1317             case 4: selectcmd = shared.select4; break;
1318             case 5: selectcmd = shared.select5; break;
1319             case 6: selectcmd = shared.select6; break;
1320             case 7: selectcmd = shared.select7; break;
1321             case 8: selectcmd = shared.select8; break;
1322             case 9: selectcmd = shared.select9; break;
1323             default:
1324                 selectcmd = createObject(REDIS_STRING,
1325                     sdscatprintf(sdsempty(),"select %d\r\n",dictid));
1326                 selectcmd->refcount = 0;
1327                 break;
1328             }
1329             addReply(slave,selectcmd);
1330             slave->slaveseldb = dictid;
1331         }
1332         for (j = 0; j < outc; j++) addReply(slave,outv[j]);
1333     }
1334     for (j = 0; j < outc; j++) decrRefCount(outv[j]);
1335     if (outv != static_outv) zfree(outv);
1336 }
1337
1338 static void readQueryFromClient(aeEventLoop *el, int fd, void *privdata, int mask) {
1339     redisClient *c = (redisClient*) privdata;
1340     char buf[REDIS_IOBUF_LEN];
1341     int nread;
1342     REDIS_NOTUSED(el);
1343     REDIS_NOTUSED(mask);
1344
1345     nread = read(fd, buf, REDIS_IOBUF_LEN);
1346     if (nread == -1) {
1347         if (errno == EAGAIN) {
1348             nread = 0;
1349         } else {
1350             redisLog(REDIS_DEBUG, "Reading from client: %s",strerror(errno));
1351             freeClient(c);
1352             return;
1353         }
1354     } else if (nread == 0) {
1355         redisLog(REDIS_DEBUG, "Client closed connection");
1356         freeClient(c);
1357         return;
1358     }
1359     if (nread) {
1360         c->querybuf = sdscatlen(c->querybuf, buf, nread);
1361         c->lastinteraction = time(NULL);
1362     } else {
1363         return;
1364     }
1365
1366 again:
1367     if (c->bulklen == -1) {
1368         /* Read the first line of the query */
1369         char *p = strchr(c->querybuf,'\n');
1370         size_t querylen;
1371         if (p) {
1372             sds query, *argv;
1373             int argc, j;
1374
1375             query = c->querybuf;
1376             c->querybuf = sdsempty();
1377             querylen = 1+(p-(query));
1378             if (sdslen(query) > querylen) {
1379                 /* leave data after the first line of the query in the buffer */
1380                 c->querybuf = sdscatlen(c->querybuf,query+querylen,sdslen(query)-querylen);
1381             }
1382             *p = '\0'; /* remove "\n" */
1383             if (*(p-1) == '\r') *(p-1) = '\0'; /* and "\r" if any */
1384             sdsupdatelen(query);
1385
1386             /* Now we can split the query in arguments */
1387             if (sdslen(query) == 0) {
1388                 /* Ignore empty query */
1389                 sdsfree(query);
1390                 return;
1391             }
1392             argv = sdssplitlen(query,sdslen(query)," ",1,&argc);
1393             if (argv == NULL) oom("sdssplitlen");
1394             sdsfree(query);
1395
1396             if (c->argv) zfree(c->argv);
1397             c->argv = zmalloc(sizeof(robj*)*argc);
1398             if (c->argv == NULL) oom("allocating arguments list for client");
1399
1400             for (j = 0; j < argc; j++) {
1401                 if (sdslen(argv[j])) {
1402                     c->argv[c->argc] = createObject(REDIS_STRING,argv[j]);
1403                     c->argc++;
1404                 } else {
1405                     sdsfree(argv[j]);
1406                 }
1407             }
1408             zfree(argv);
1409             /* Execute the command. If the client is still valid
1410              * after processCommand() return and there is something
1411              * on the query buffer try to process the next command. */
1412             if (processCommand(c) && sdslen(c->querybuf)) goto again;
1413             return;
1414         } else if (sdslen(c->querybuf) >= 1024) {
1415             redisLog(REDIS_DEBUG, "Client protocol error");
1416             freeClient(c);
1417             return;
1418         }
1419     } else {
1420         /* Bulk read handling. Note that if we are at this point
1421            the client already sent a command terminated with a newline,
1422            we are reading the bulk data that is actually the last
1423            argument of the command. */
1424         int qbl = sdslen(c->querybuf);
1425
1426         if (c->bulklen <= qbl) {
1427             /* Copy everything but the final CRLF as final argument */
1428             c->argv[c->argc] = createStringObject(c->querybuf,c->bulklen-2);
1429             c->argc++;
1430             c->querybuf = sdsrange(c->querybuf,c->bulklen,-1);
1431             processCommand(c);
1432             return;
1433         }
1434     }
1435 }
1436
1437 static int selectDb(redisClient *c, int id) {
1438     if (id < 0 || id >= server.dbnum)
1439         return REDIS_ERR;
1440     c->db = &server.db[id];
1441     return REDIS_OK;
1442 }
1443
1444 static void *dupClientReplyValue(void *o) {
1445     incrRefCount((robj*)o);
1446     return 0;
1447 }
1448
1449 static redisClient *createClient(int fd) {
1450     redisClient *c = zmalloc(sizeof(*c));
1451
1452     anetNonBlock(NULL,fd);
1453     anetTcpNoDelay(NULL,fd);
1454     if (!c) return NULL;
1455     selectDb(c,0);
1456     c->fd = fd;
1457     c->querybuf = sdsempty();
1458     c->argc = 0;
1459     c->argv = NULL;
1460     c->bulklen = -1;
1461     c->sentlen = 0;
1462     c->flags = 0;
1463     c->lastinteraction = time(NULL);
1464     c->authenticated = 0;
1465     c->replstate = REDIS_REPL_NONE;
1466     if ((c->reply = listCreate()) == NULL) oom("listCreate");
1467     listSetFreeMethod(c->reply,decrRefCount);
1468     listSetDupMethod(c->reply,dupClientReplyValue);
1469     if (aeCreateFileEvent(server.el, c->fd, AE_READABLE,
1470         readQueryFromClient, c, NULL) == AE_ERR) {
1471         freeClient(c);
1472         return NULL;
1473     }
1474     if (!listAddNodeTail(server.clients,c)) oom("listAddNodeTail");
1475     return c;
1476 }
1477
1478 static void addReply(redisClient *c, robj *obj) {
1479     if (listLength(c->reply) == 0 &&
1480         (c->replstate == REDIS_REPL_NONE ||
1481          c->replstate == REDIS_REPL_ONLINE) &&
1482         aeCreateFileEvent(server.el, c->fd, AE_WRITABLE,
1483         sendReplyToClient, c, NULL) == AE_ERR) return;
1484     if (!listAddNodeTail(c->reply,obj)) oom("listAddNodeTail");
1485     incrRefCount(obj);
1486 }
1487
1488 static void addReplySds(redisClient *c, sds s) {
1489     robj *o = createObject(REDIS_STRING,s);
1490     addReply(c,o);
1491     decrRefCount(o);
1492 }
1493
1494 static void acceptHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
1495     int cport, cfd;
1496     char cip[128];
1497     REDIS_NOTUSED(el);
1498     REDIS_NOTUSED(mask);
1499     REDIS_NOTUSED(privdata);
1500
1501     cfd = anetAccept(server.neterr, fd, cip, &cport);
1502     if (cfd == AE_ERR) {
1503         redisLog(REDIS_DEBUG,"Accepting client connection: %s", server.neterr);
1504         return;
1505     }
1506     redisLog(REDIS_DEBUG,"Accepted %s:%d", cip, cport);
1507     if (createClient(cfd) == NULL) {
1508         redisLog(REDIS_WARNING,"Error allocating resoures for the client");
1509         close(cfd); /* May be already closed, just ingore errors */
1510         return;
1511     }
1512     server.stat_numconnections++;
1513 }
1514
1515 /* ======================= Redis objects implementation ===================== */
1516
1517 static robj *createObject(int type, void *ptr) {
1518     robj *o;
1519
1520     if (listLength(server.objfreelist)) {
1521         listNode *head = listFirst(server.objfreelist);
1522         o = listNodeValue(head);
1523         listDelNode(server.objfreelist,head);
1524     } else {
1525         o = zmalloc(sizeof(*o));
1526     }
1527     if (!o) oom("createObject");
1528     o->type = type;
1529     o->ptr = ptr;
1530     o->refcount = 1;
1531     return o;
1532 }
1533
1534 static robj *createStringObject(char *ptr, size_t len) {
1535     return createObject(REDIS_STRING,sdsnewlen(ptr,len));
1536 }
1537
1538 static robj *createListObject(void) {
1539     list *l = listCreate();
1540
1541     if (!l) oom("listCreate");
1542     listSetFreeMethod(l,decrRefCount);
1543     return createObject(REDIS_LIST,l);
1544 }
1545
1546 static robj *createSetObject(void) {
1547     dict *d = dictCreate(&setDictType,NULL);
1548     if (!d) oom("dictCreate");
1549     return createObject(REDIS_SET,d);
1550 }
1551
1552 static void freeStringObject(robj *o) {
1553     sdsfree(o->ptr);
1554 }
1555
1556 static void freeListObject(robj *o) {
1557     listRelease((list*) o->ptr);
1558 }
1559
1560 static void freeSetObject(robj *o) {
1561     dictRelease((dict*) o->ptr);
1562 }
1563
1564 static void freeHashObject(robj *o) {
1565     dictRelease((dict*) o->ptr);
1566 }
1567
1568 static void incrRefCount(robj *o) {
1569     o->refcount++;
1570 #ifdef DEBUG_REFCOUNT
1571     if (o->type == REDIS_STRING)
1572         printf("Increment '%s'(%p), now is: %d\n",o->ptr,o,o->refcount);
1573 #endif
1574 }
1575
1576 static void decrRefCount(void *obj) {
1577     robj *o = obj;
1578
1579 #ifdef DEBUG_REFCOUNT
1580     if (o->type == REDIS_STRING)
1581         printf("Decrement '%s'(%p), now is: %d\n",o->ptr,o,o->refcount-1);
1582 #endif
1583     if (--(o->refcount) == 0) {
1584         switch(o->type) {
1585         case REDIS_STRING: freeStringObject(o); break;
1586         case REDIS_LIST: freeListObject(o); break;
1587         case REDIS_SET: freeSetObject(o); break;
1588         case REDIS_HASH: freeHashObject(o); break;
1589         default: assert(0 != 0); break;
1590         }
1591         if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX ||
1592             !listAddNodeHead(server.objfreelist,o))
1593             zfree(o);
1594     }
1595 }
1596
1597 /* Try to share an object against the shared objects pool */
1598 static robj *tryObjectSharing(robj *o) {
1599     struct dictEntry *de;
1600     unsigned long c;
1601
1602     if (o == NULL || server.shareobjects == 0) return o;
1603
1604     assert(o->type == REDIS_STRING);
1605     de = dictFind(server.sharingpool,o);
1606     if (de) {
1607         robj *shared = dictGetEntryKey(de);
1608
1609         c = ((unsigned long) dictGetEntryVal(de))+1;
1610         dictGetEntryVal(de) = (void*) c;
1611         incrRefCount(shared);
1612         decrRefCount(o);
1613         return shared;
1614     } else {
1615         /* Here we are using a stream algorihtm: Every time an object is
1616          * shared we increment its count, everytime there is a miss we
1617          * recrement the counter of a random object. If this object reaches
1618          * zero we remove the object and put the current object instead. */
1619         if (dictSize(server.sharingpool) >=
1620                 server.sharingpoolsize) {
1621             de = dictGetRandomKey(server.sharingpool);
1622             assert(de != NULL);
1623             c = ((unsigned long) dictGetEntryVal(de))-1;
1624             dictGetEntryVal(de) = (void*) c;
1625             if (c == 0) {
1626                 dictDelete(server.sharingpool,de->key);
1627             }
1628         } else {
1629             c = 0; /* If the pool is empty we want to add this object */
1630         }
1631         if (c == 0) {
1632             int retval;
1633
1634             retval = dictAdd(server.sharingpool,o,(void*)1);
1635             assert(retval == DICT_OK);
1636             incrRefCount(o);
1637         }
1638         return o;
1639     }
1640 }
1641
1642 static robj *lookupKey(redisDb *db, robj *key) {
1643     dictEntry *de = dictFind(db->dict,key);
1644     return de ? dictGetEntryVal(de) : NULL;
1645 }
1646
1647 static robj *lookupKeyRead(redisDb *db, robj *key) {
1648     expireIfNeeded(db,key);
1649     return lookupKey(db,key);
1650 }
1651
1652 static robj *lookupKeyWrite(redisDb *db, robj *key) {
1653     deleteIfVolatile(db,key);
1654     return lookupKey(db,key);
1655 }
1656
1657 static int deleteKey(redisDb *db, robj *key) {
1658     int retval;
1659
1660     /* We need to protect key from destruction: after the first dictDelete()
1661      * it may happen that 'key' is no longer valid if we don't increment
1662      * it's count. This may happen when we get the object reference directly
1663      * from the hash table with dictRandomKey() or dict iterators */
1664     incrRefCount(key);
1665     if (dictSize(db->expires)) dictDelete(db->expires,key);
1666     retval = dictDelete(db->dict,key);
1667     decrRefCount(key);
1668
1669     return retval == DICT_OK;
1670 }
1671
1672 /*============================ DB saving/loading ============================ */
1673
1674 static int rdbSaveType(FILE *fp, unsigned char type) {
1675     if (fwrite(&type,1,1,fp) == 0) return -1;
1676     return 0;
1677 }
1678
1679 static int rdbSaveTime(FILE *fp, time_t t) {
1680     int32_t t32 = (int32_t) t;
1681     if (fwrite(&t32,4,1,fp) == 0) return -1;
1682     return 0;
1683 }
1684
1685 /* check rdbLoadLen() comments for more info */
1686 static int rdbSaveLen(FILE *fp, uint32_t len) {
1687     unsigned char buf[2];
1688
1689     if (len < (1<<6)) {
1690         /* Save a 6 bit len */
1691         buf[0] = (len&0xFF)|(REDIS_RDB_6BITLEN<<6);
1692         if (fwrite(buf,1,1,fp) == 0) return -1;
1693     } else if (len < (1<<14)) {
1694         /* Save a 14 bit len */
1695         buf[0] = ((len>>8)&0xFF)|(REDIS_RDB_14BITLEN<<6);
1696         buf[1] = len&0xFF;
1697         if (fwrite(buf,2,1,fp) == 0) return -1;
1698     } else {
1699         /* Save a 32 bit len */
1700         buf[0] = (REDIS_RDB_32BITLEN<<6);
1701         if (fwrite(buf,1,1,fp) == 0) return -1;
1702         len = htonl(len);
1703         if (fwrite(&len,4,1,fp) == 0) return -1;
1704     }
1705     return 0;
1706 }
1707
1708 /* String objects in the form "2391" "-100" without any space and with a
1709  * range of values that can fit in an 8, 16 or 32 bit signed value can be
1710  * encoded as integers to save space */
1711 int rdbTryIntegerEncoding(sds s, unsigned char *enc) {
1712     long long value;
1713     char *endptr, buf[32];
1714
1715     /* Check if it's possible to encode this value as a number */
1716     value = strtoll(s, &endptr, 10);
1717     if (endptr[0] != '\0') return 0;
1718     snprintf(buf,32,"%lld",value);
1719
1720     /* If the number converted back into a string is not identical
1721      * then it's not possible to encode the string as integer */
1722     if (strlen(buf) != sdslen(s) || memcmp(buf,s,sdslen(s))) return 0;
1723
1724     /* Finally check if it fits in our ranges */
1725     if (value >= -(1<<7) && value <= (1<<7)-1) {
1726         enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT8;
1727         enc[1] = value&0xFF;
1728         return 2;
1729     } else if (value >= -(1<<15) && value <= (1<<15)-1) {
1730         enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT16;
1731         enc[1] = value&0xFF;
1732         enc[2] = (value>>8)&0xFF;
1733         return 3;
1734     } else if (value >= -((long long)1<<31) && value <= ((long long)1<<31)-1) {
1735         enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT32;
1736         enc[1] = value&0xFF;
1737         enc[2] = (value>>8)&0xFF;
1738         enc[3] = (value>>16)&0xFF;
1739         enc[4] = (value>>24)&0xFF;
1740         return 5;
1741     } else {
1742         return 0;
1743     }
1744 }
1745
1746 static int rdbSaveLzfStringObject(FILE *fp, robj *obj) {
1747     unsigned int comprlen, outlen;
1748     unsigned char byte;
1749     void *out;
1750
1751     /* We require at least four bytes compression for this to be worth it */
1752     outlen = sdslen(obj->ptr)-4;
1753     if (outlen <= 0) return 0;
1754     if ((out = zmalloc(outlen+1)) == NULL) return 0;
1755     comprlen = lzf_compress(obj->ptr, sdslen(obj->ptr), out, outlen);
1756     if (comprlen == 0) {
1757         zfree(out);
1758         return 0;
1759     }
1760     /* Data compressed! Let's save it on disk */
1761     byte = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_LZF;
1762     if (fwrite(&byte,1,1,fp) == 0) goto writeerr;
1763     if (rdbSaveLen(fp,comprlen) == -1) goto writeerr;
1764     if (rdbSaveLen(fp,sdslen(obj->ptr)) == -1) goto writeerr;
1765     if (fwrite(out,comprlen,1,fp) == 0) goto writeerr;
1766     zfree(out);
1767     return comprlen;
1768
1769 writeerr:
1770     zfree(out);
1771     return -1;
1772 }
1773
1774 /* Save a string objet as [len][data] on disk. If the object is a string
1775  * representation of an integer value we try to safe it in a special form */
1776 static int rdbSaveStringObject(FILE *fp, robj *obj) {
1777     size_t len = sdslen(obj->ptr);
1778     int enclen;
1779
1780     /* Try integer encoding */
1781     if (len <= 11) {
1782         unsigned char buf[5];
1783         if ((enclen = rdbTryIntegerEncoding(obj->ptr,buf)) > 0) {
1784             if (fwrite(buf,enclen,1,fp) == 0) return -1;
1785             return 0;
1786         }
1787     }
1788
1789     /* Try LZF compression - under 20 bytes it's unable to compress even
1790      * aaaaaaaaaaaaaaaaaa so skip it */
1791     if (1 && len > 20) {
1792         int retval;
1793
1794         retval = rdbSaveLzfStringObject(fp,obj);
1795         if (retval == -1) return -1;
1796         if (retval > 0) return 0;
1797         /* retval == 0 means data can't be compressed, save the old way */
1798     }
1799
1800     /* Store verbatim */
1801     if (rdbSaveLen(fp,len) == -1) return -1;
1802     if (len && fwrite(obj->ptr,len,1,fp) == 0) return -1;
1803     return 0;
1804 }
1805
1806 /* Save the DB on disk. Return REDIS_ERR on error, REDIS_OK on success */
1807 static int rdbSave(char *filename) {
1808     dictIterator *di = NULL;
1809     dictEntry *de;
1810     FILE *fp;
1811     char tmpfile[256];
1812     int j;
1813     time_t now = time(NULL);
1814
1815     snprintf(tmpfile,256,"temp-%d.%ld.rdb",(int)time(NULL),(long int)random());
1816     fp = fopen(tmpfile,"w");
1817     if (!fp) {
1818         redisLog(REDIS_WARNING, "Failed saving the DB: %s", strerror(errno));
1819         return REDIS_ERR;
1820     }
1821     if (fwrite("REDIS0001",9,1,fp) == 0) goto werr;
1822     for (j = 0; j < server.dbnum; j++) {
1823         redisDb *db = server.db+j;
1824         dict *d = db->dict;
1825         if (dictSize(d) == 0) continue;
1826         di = dictGetIterator(d);
1827         if (!di) {
1828             fclose(fp);
1829             return REDIS_ERR;
1830         }
1831
1832         /* Write the SELECT DB opcode */
1833         if (rdbSaveType(fp,REDIS_SELECTDB) == -1) goto werr;
1834         if (rdbSaveLen(fp,j) == -1) goto werr;
1835
1836         /* Iterate this DB writing every entry */
1837         while((de = dictNext(di)) != NULL) {
1838             robj *key = dictGetEntryKey(de);
1839             robj *o = dictGetEntryVal(de);
1840             time_t expiretime = getExpire(db,key);
1841
1842             /* Save the expire time */
1843             if (expiretime != -1) {
1844                 /* If this key is already expired skip it */
1845                 if (expiretime < now) continue;
1846                 if (rdbSaveType(fp,REDIS_EXPIRETIME) == -1) goto werr;
1847                 if (rdbSaveTime(fp,expiretime) == -1) goto werr;
1848             }
1849             /* Save the key and associated value */
1850             if (rdbSaveType(fp,o->type) == -1) goto werr;
1851             if (rdbSaveStringObject(fp,key) == -1) goto werr;
1852             if (o->type == REDIS_STRING) {
1853                 /* Save a string value */
1854                 if (rdbSaveStringObject(fp,o) == -1) goto werr;
1855             } else if (o->type == REDIS_LIST) {
1856                 /* Save a list value */
1857                 list *list = o->ptr;
1858                 listNode *ln;
1859
1860                 listRewind(list);
1861                 if (rdbSaveLen(fp,listLength(list)) == -1) goto werr;
1862                 while((ln = listYield(list))) {
1863                     robj *eleobj = listNodeValue(ln);
1864
1865                     if (rdbSaveStringObject(fp,eleobj) == -1) goto werr;
1866                 }
1867             } else if (o->type == REDIS_SET) {
1868                 /* Save a set value */
1869                 dict *set = o->ptr;
1870                 dictIterator *di = dictGetIterator(set);
1871                 dictEntry *de;
1872
1873                 if (!set) oom("dictGetIteraotr");
1874                 if (rdbSaveLen(fp,dictSize(set)) == -1) goto werr;
1875                 while((de = dictNext(di)) != NULL) {
1876                     robj *eleobj = dictGetEntryKey(de);
1877
1878                     if (rdbSaveStringObject(fp,eleobj) == -1) goto werr;
1879                 }
1880                 dictReleaseIterator(di);
1881             } else {
1882                 assert(0 != 0);
1883             }
1884         }
1885         dictReleaseIterator(di);
1886     }
1887     /* EOF opcode */
1888     if (rdbSaveType(fp,REDIS_EOF) == -1) goto werr;
1889
1890     /* Make sure data will not remain on the OS's output buffers */
1891     fflush(fp);
1892     fsync(fileno(fp));
1893     fclose(fp);
1894
1895     /* Use RENAME to make sure the DB file is changed atomically only
1896      * if the generate DB file is ok. */
1897     if (rename(tmpfile,filename) == -1) {
1898         redisLog(REDIS_WARNING,"Error moving temp DB file on the final destionation: %s", strerror(errno));
1899         unlink(tmpfile);
1900         return REDIS_ERR;
1901     }
1902     redisLog(REDIS_NOTICE,"DB saved on disk");
1903     server.dirty = 0;
1904     server.lastsave = time(NULL);
1905     return REDIS_OK;
1906
1907 werr:
1908     fclose(fp);
1909     unlink(tmpfile);
1910     redisLog(REDIS_WARNING,"Write error saving DB on disk: %s", strerror(errno));
1911     if (di) dictReleaseIterator(di);
1912     return REDIS_ERR;
1913 }
1914
1915 static int rdbSaveBackground(char *filename) {
1916     pid_t childpid;
1917
1918     if (server.bgsaveinprogress) return REDIS_ERR;
1919     if ((childpid = fork()) == 0) {
1920         /* Child */
1921         close(server.fd);
1922         if (rdbSave(filename) == REDIS_OK) {
1923             exit(0);
1924         } else {
1925             exit(1);
1926         }
1927     } else {
1928         /* Parent */
1929         if (childpid == -1) {
1930             redisLog(REDIS_WARNING,"Can't save in background: fork: %s",
1931                 strerror(errno));
1932             return REDIS_ERR;
1933         }
1934         redisLog(REDIS_NOTICE,"Background saving started by pid %d",childpid);
1935         server.bgsaveinprogress = 1;
1936         return REDIS_OK;
1937     }
1938     return REDIS_OK; /* unreached */
1939 }
1940
1941 static int rdbLoadType(FILE *fp) {
1942     unsigned char type;
1943     if (fread(&type,1,1,fp) == 0) return -1;
1944     return type;
1945 }
1946
1947 static time_t rdbLoadTime(FILE *fp) {
1948     int32_t t32;
1949     if (fread(&t32,4,1,fp) == 0) return -1;
1950     return (time_t) t32;
1951 }
1952
1953 /* Load an encoded length from the DB, see the REDIS_RDB_* defines on the top
1954  * of this file for a description of how this are stored on disk.
1955  *
1956  * isencoded is set to 1 if the readed length is not actually a length but
1957  * an "encoding type", check the above comments for more info */
1958 static uint32_t rdbLoadLen(FILE *fp, int rdbver, int *isencoded) {
1959     unsigned char buf[2];
1960     uint32_t len;
1961
1962     if (isencoded) *isencoded = 0;
1963     if (rdbver == 0) {
1964         if (fread(&len,4,1,fp) == 0) return REDIS_RDB_LENERR;
1965         return ntohl(len);
1966     } else {
1967         int type;
1968
1969         if (fread(buf,1,1,fp) == 0) return REDIS_RDB_LENERR;
1970         type = (buf[0]&0xC0)>>6;
1971         if (type == REDIS_RDB_6BITLEN) {
1972             /* Read a 6 bit len */
1973             return buf[0]&0x3F;
1974         } else if (type == REDIS_RDB_ENCVAL) {
1975             /* Read a 6 bit len encoding type */
1976             if (isencoded) *isencoded = 1;
1977             return buf[0]&0x3F;
1978         } else if (type == REDIS_RDB_14BITLEN) {
1979             /* Read a 14 bit len */
1980             if (fread(buf+1,1,1,fp) == 0) return REDIS_RDB_LENERR;
1981             return ((buf[0]&0x3F)<<8)|buf[1];
1982         } else {
1983             /* Read a 32 bit len */
1984             if (fread(&len,4,1,fp) == 0) return REDIS_RDB_LENERR;
1985             return ntohl(len);
1986         }
1987     }
1988 }
1989
1990 static robj *rdbLoadIntegerObject(FILE *fp, int enctype) {
1991     unsigned char enc[4];
1992     long long val;
1993
1994     if (enctype == REDIS_RDB_ENC_INT8) {
1995         if (fread(enc,1,1,fp) == 0) return NULL;
1996         val = (signed char)enc[0];
1997     } else if (enctype == REDIS_RDB_ENC_INT16) {
1998         uint16_t v;
1999         if (fread(enc,2,1,fp) == 0) return NULL;
2000         v = enc[0]|(enc[1]<<8);
2001         val = (int16_t)v;
2002     } else if (enctype == REDIS_RDB_ENC_INT32) {
2003         uint32_t v;
2004         if (fread(enc,4,1,fp) == 0) return NULL;
2005         v = enc[0]|(enc[1]<<8)|(enc[2]<<16)|(enc[3]<<24);
2006         val = (int32_t)v;
2007     } else {
2008         val = 0; /* anti-warning */
2009         assert(0!=0);
2010     }
2011     return createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",val));
2012 }
2013
2014 static robj *rdbLoadLzfStringObject(FILE*fp, int rdbver) {
2015     unsigned int len, clen;
2016     unsigned char *c = NULL;
2017     sds val = NULL;
2018
2019     if ((clen = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR) return NULL;
2020     if ((len = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR) return NULL;
2021     if ((c = zmalloc(clen)) == NULL) goto err;
2022     if ((val = sdsnewlen(NULL,len)) == NULL) goto err;
2023     if (fread(c,clen,1,fp) == 0) goto err;
2024     if (lzf_decompress(c,clen,val,len) == 0) goto err;
2025     zfree(c);
2026     return createObject(REDIS_STRING,val);
2027 err:
2028     zfree(c);
2029     sdsfree(val);
2030     return NULL;
2031 }
2032
2033 static robj *rdbLoadStringObject(FILE*fp, int rdbver) {
2034     int isencoded;
2035     uint32_t len;
2036     sds val;
2037
2038     len = rdbLoadLen(fp,rdbver,&isencoded);
2039     if (isencoded) {
2040         switch(len) {
2041         case REDIS_RDB_ENC_INT8:
2042         case REDIS_RDB_ENC_INT16:
2043         case REDIS_RDB_ENC_INT32:
2044             return tryObjectSharing(rdbLoadIntegerObject(fp,len));
2045         case REDIS_RDB_ENC_LZF:
2046             return tryObjectSharing(rdbLoadLzfStringObject(fp,rdbver));
2047         default:
2048             assert(0!=0);
2049         }
2050     }
2051
2052     if (len == REDIS_RDB_LENERR) return NULL;
2053     val = sdsnewlen(NULL,len);
2054     if (len && fread(val,len,1,fp) == 0) {
2055         sdsfree(val);
2056         return NULL;
2057     }
2058     return tryObjectSharing(createObject(REDIS_STRING,val));
2059 }
2060
2061 static int rdbLoad(char *filename) {
2062     FILE *fp;
2063     robj *keyobj = NULL;
2064     uint32_t dbid;
2065     int type, retval, rdbver;
2066     dict *d = server.db[0].dict;
2067     redisDb *db = server.db+0;
2068     char buf[1024];
2069     time_t expiretime = -1, now = time(NULL);
2070
2071     fp = fopen(filename,"r");
2072     if (!fp) return REDIS_ERR;
2073     if (fread(buf,9,1,fp) == 0) goto eoferr;
2074     buf[9] = '\0';
2075     if (memcmp(buf,"REDIS",5) != 0) {
2076         fclose(fp);
2077         redisLog(REDIS_WARNING,"Wrong signature trying to load DB from file");
2078         return REDIS_ERR;
2079     }
2080     rdbver = atoi(buf+5);
2081     if (rdbver > 1) {
2082         fclose(fp);
2083         redisLog(REDIS_WARNING,"Can't handle RDB format version %d",rdbver);
2084         return REDIS_ERR;
2085     }
2086     while(1) {
2087         robj *o;
2088
2089         /* Read type. */
2090         if ((type = rdbLoadType(fp)) == -1) goto eoferr;
2091         if (type == REDIS_EXPIRETIME) {
2092             if ((expiretime = rdbLoadTime(fp)) == -1) goto eoferr;
2093             /* We read the time so we need to read the object type again */
2094             if ((type = rdbLoadType(fp)) == -1) goto eoferr;
2095         }
2096         if (type == REDIS_EOF) break;
2097         /* Handle SELECT DB opcode as a special case */
2098         if (type == REDIS_SELECTDB) {
2099             if ((dbid = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR)
2100                 goto eoferr;
2101             if (dbid >= (unsigned)server.dbnum) {
2102                 redisLog(REDIS_WARNING,"FATAL: Data file was created with a Redis server configured to handle more than %d databases. Exiting\n", server.dbnum);
2103                 exit(1);
2104             }
2105             db = server.db+dbid;
2106             d = db->dict;
2107             continue;
2108         }
2109         /* Read key */
2110         if ((keyobj = rdbLoadStringObject(fp,rdbver)) == NULL) goto eoferr;
2111
2112         if (type == REDIS_STRING) {
2113             /* Read string value */
2114             if ((o = rdbLoadStringObject(fp,rdbver)) == NULL) goto eoferr;
2115         } else if (type == REDIS_LIST || type == REDIS_SET) {
2116             /* Read list/set value */
2117             uint32_t listlen;
2118
2119             if ((listlen = rdbLoadLen(fp,rdbver,NULL)) == REDIS_RDB_LENERR)
2120                 goto eoferr;
2121             o = (type == REDIS_LIST) ? createListObject() : createSetObject();
2122             /* Load every single element of the list/set */
2123             while(listlen--) {
2124                 robj *ele;
2125
2126                 if ((ele = rdbLoadStringObject(fp,rdbver)) == NULL) goto eoferr;
2127                 if (type == REDIS_LIST) {
2128                     if (!listAddNodeTail((list*)o->ptr,ele))
2129                         oom("listAddNodeTail");
2130                 } else {
2131                     if (dictAdd((dict*)o->ptr,ele,NULL) == DICT_ERR)
2132                         oom("dictAdd");
2133                 }
2134             }
2135         } else {
2136             assert(0 != 0);
2137         }
2138         /* Add the new object in the hash table */
2139         retval = dictAdd(d,keyobj,o);
2140         if (retval == DICT_ERR) {
2141             redisLog(REDIS_WARNING,"Loading DB, duplicated key (%s) found! Unrecoverable error, exiting now.", keyobj->ptr);
2142             exit(1);
2143         }
2144         /* Set the expire time if needed */
2145         if (expiretime != -1) {
2146             setExpire(db,keyobj,expiretime);
2147             /* Delete this key if already expired */
2148             if (expiretime < now) deleteKey(db,keyobj);
2149             expiretime = -1;
2150         }
2151         keyobj = o = NULL;
2152     }
2153     fclose(fp);
2154     return REDIS_OK;
2155
2156 eoferr: /* unexpected end of file is handled here with a fatal exit */
2157     if (keyobj) decrRefCount(keyobj);
2158     redisLog(REDIS_WARNING,"Short read or OOM loading DB. Unrecoverable error, exiting now.");
2159     exit(1);
2160     return REDIS_ERR; /* Just to avoid warning */
2161 }
2162
2163 /*================================== Commands =============================== */
2164
2165 static void authCommand(redisClient *c) {
2166     if (!server.requirepass || !strcmp(c->argv[1]->ptr, server.requirepass)) {
2167       c->authenticated = 1;
2168       addReply(c,shared.ok);
2169     } else {
2170       c->authenticated = 0;
2171       addReply(c,shared.err);
2172     }
2173 }
2174
2175 static void pingCommand(redisClient *c) {
2176     addReply(c,shared.pong);
2177 }
2178
2179 static void echoCommand(redisClient *c) {
2180     addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",
2181         (int)sdslen(c->argv[1]->ptr)));
2182     addReply(c,c->argv[1]);
2183     addReply(c,shared.crlf);
2184 }
2185
2186 /*=================================== Strings =============================== */
2187
2188 static void setGenericCommand(redisClient *c, int nx) {
2189     int retval;
2190
2191     retval = dictAdd(c->db->dict,c->argv[1],c->argv[2]);
2192     if (retval == DICT_ERR) {
2193         if (!nx) {
2194             dictReplace(c->db->dict,c->argv[1],c->argv[2]);
2195             incrRefCount(c->argv[2]);
2196         } else {
2197             addReply(c,shared.czero);
2198             return;
2199         }
2200     } else {
2201         incrRefCount(c->argv[1]);
2202         incrRefCount(c->argv[2]);
2203     }
2204     server.dirty++;
2205     removeExpire(c->db,c->argv[1]);
2206     addReply(c, nx ? shared.cone : shared.ok);
2207 }
2208
2209 static void setCommand(redisClient *c) {
2210     setGenericCommand(c,0);
2211 }
2212
2213 static void setnxCommand(redisClient *c) {
2214     setGenericCommand(c,1);
2215 }
2216
2217 static void getCommand(redisClient *c) {
2218     robj *o = lookupKeyRead(c->db,c->argv[1]);
2219
2220     if (o == NULL) {
2221         addReply(c,shared.nullbulk);
2222     } else {
2223         if (o->type != REDIS_STRING) {
2224             addReply(c,shared.wrongtypeerr);
2225         } else {
2226             addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(o->ptr)));
2227             addReply(c,o);
2228             addReply(c,shared.crlf);
2229         }
2230     }
2231 }
2232
2233 static void getSetCommand(redisClient *c) {
2234     getCommand(c);
2235     if (dictAdd(c->db->dict,c->argv[1],c->argv[2]) == DICT_ERR) {
2236         dictReplace(c->db->dict,c->argv[1],c->argv[2]);
2237     } else {
2238         incrRefCount(c->argv[1]);
2239     }
2240     incrRefCount(c->argv[2]);
2241     server.dirty++;
2242     removeExpire(c->db,c->argv[1]);
2243 }
2244
2245 static void mgetCommand(redisClient *c) {
2246     int j;
2247
2248     addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",c->argc-1));
2249     for (j = 1; j < c->argc; j++) {
2250         robj *o = lookupKeyRead(c->db,c->argv[j]);
2251         if (o == NULL) {
2252             addReply(c,shared.nullbulk);
2253         } else {
2254             if (o->type != REDIS_STRING) {
2255                 addReply(c,shared.nullbulk);
2256             } else {
2257                 addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(o->ptr)));
2258                 addReply(c,o);
2259                 addReply(c,shared.crlf);
2260             }
2261         }
2262     }
2263 }
2264
2265 static void incrDecrCommand(redisClient *c, long long incr) {
2266     long long value;
2267     int retval;
2268     robj *o;
2269
2270     o = lookupKeyWrite(c->db,c->argv[1]);
2271     if (o == NULL) {
2272         value = 0;
2273     } else {
2274         if (o->type != REDIS_STRING) {
2275             value = 0;
2276         } else {
2277             char *eptr;
2278
2279             value = strtoll(o->ptr, &eptr, 10);
2280         }
2281     }
2282
2283     value += incr;
2284     o = createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",value));
2285     retval = dictAdd(c->db->dict,c->argv[1],o);
2286     if (retval == DICT_ERR) {
2287         dictReplace(c->db->dict,c->argv[1],o);
2288         removeExpire(c->db,c->argv[1]);
2289     } else {
2290         incrRefCount(c->argv[1]);
2291     }
2292     server.dirty++;
2293     addReply(c,shared.colon);
2294     addReply(c,o);
2295     addReply(c,shared.crlf);
2296 }
2297
2298 static void incrCommand(redisClient *c) {
2299     incrDecrCommand(c,1);
2300 }
2301
2302 static void decrCommand(redisClient *c) {
2303     incrDecrCommand(c,-1);
2304 }
2305
2306 static void incrbyCommand(redisClient *c) {
2307     long long incr = strtoll(c->argv[2]->ptr, NULL, 10);
2308     incrDecrCommand(c,incr);
2309 }
2310
2311 static void decrbyCommand(redisClient *c) {
2312     long long incr = strtoll(c->argv[2]->ptr, NULL, 10);
2313     incrDecrCommand(c,-incr);
2314 }
2315
2316 /* ========================= Type agnostic commands ========================= */
2317
2318 static void delCommand(redisClient *c) {
2319     int deleted = 0, j;
2320
2321     for (j = 1; j < c->argc; j++) {
2322         if (deleteKey(c->db,c->argv[j])) {
2323             server.dirty++;
2324             deleted++;
2325         }
2326     }
2327     switch(deleted) {
2328     case 0:
2329         addReply(c,shared.czero);
2330         break;
2331     case 1:
2332         addReply(c,shared.cone);
2333         break;
2334     default:
2335         addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",deleted));
2336         break;
2337     }
2338 }
2339
2340 static void existsCommand(redisClient *c) {
2341     addReply(c,lookupKeyRead(c->db,c->argv[1]) ? shared.cone : shared.czero);
2342 }
2343
2344 static void selectCommand(redisClient *c) {
2345     int id = atoi(c->argv[1]->ptr);
2346
2347     if (selectDb(c,id) == REDIS_ERR) {
2348         addReplySds(c,sdsnew("-ERR invalid DB index\r\n"));
2349     } else {
2350         addReply(c,shared.ok);
2351     }
2352 }
2353
2354 static void randomkeyCommand(redisClient *c) {
2355     dictEntry *de;
2356
2357     while(1) {
2358         de = dictGetRandomKey(c->db->dict);
2359         if (!de || expireIfNeeded(c->db,dictGetEntryKey(de)) == 0) break;
2360     }
2361     if (de == NULL) {
2362         addReply(c,shared.plus);
2363         addReply(c,shared.crlf);
2364     } else {
2365         addReply(c,shared.plus);
2366         addReply(c,dictGetEntryKey(de));
2367         addReply(c,shared.crlf);
2368     }
2369 }
2370
2371 static void keysCommand(redisClient *c) {
2372     dictIterator *di;
2373     dictEntry *de;
2374     sds pattern = c->argv[1]->ptr;
2375     int plen = sdslen(pattern);
2376     int numkeys = 0, keyslen = 0;
2377     robj *lenobj = createObject(REDIS_STRING,NULL);
2378
2379     di = dictGetIterator(c->db->dict);
2380     if (!di) oom("dictGetIterator");
2381     addReply(c,lenobj);
2382     decrRefCount(lenobj);
2383     while((de = dictNext(di)) != NULL) {
2384         robj *keyobj = dictGetEntryKey(de);
2385
2386         sds key = keyobj->ptr;
2387         if ((pattern[0] == '*' && pattern[1] == '\0') ||
2388             stringmatchlen(pattern,plen,key,sdslen(key),0)) {
2389             if (expireIfNeeded(c->db,keyobj) == 0) {
2390                 if (numkeys != 0)
2391                     addReply(c,shared.space);
2392                 addReply(c,keyobj);
2393                 numkeys++;
2394                 keyslen += sdslen(key);
2395             }
2396         }
2397     }
2398     dictReleaseIterator(di);
2399     lenobj->ptr = sdscatprintf(sdsempty(),"$%lu\r\n",keyslen+(numkeys ? (numkeys-1) : 0));
2400     addReply(c,shared.crlf);
2401 }
2402
2403 static void dbsizeCommand(redisClient *c) {
2404     addReplySds(c,
2405         sdscatprintf(sdsempty(),":%lu\r\n",dictSize(c->db->dict)));
2406 }
2407
2408 static void lastsaveCommand(redisClient *c) {
2409     addReplySds(c,
2410         sdscatprintf(sdsempty(),":%lu\r\n",server.lastsave));
2411 }
2412
2413 static void typeCommand(redisClient *c) {
2414     robj *o;
2415     char *type;
2416
2417     o = lookupKeyRead(c->db,c->argv[1]);
2418     if (o == NULL) {
2419         type = "+none";
2420     } else {
2421         switch(o->type) {
2422         case REDIS_STRING: type = "+string"; break;
2423         case REDIS_LIST: type = "+list"; break;
2424         case REDIS_SET: type = "+set"; break;
2425         default: type = "unknown"; break;
2426         }
2427     }
2428     addReplySds(c,sdsnew(type));
2429     addReply(c,shared.crlf);
2430 }
2431
2432 static void saveCommand(redisClient *c) {
2433     if (server.bgsaveinprogress) {
2434         addReplySds(c,sdsnew("-ERR background save in progress\r\n"));
2435         return;
2436     }
2437     if (rdbSave(server.dbfilename) == REDIS_OK) {
2438         addReply(c,shared.ok);
2439     } else {
2440         addReply(c,shared.err);
2441     }
2442 }
2443
2444 static void bgsaveCommand(redisClient *c) {
2445     if (server.bgsaveinprogress) {
2446         addReplySds(c,sdsnew("-ERR background save already in progress\r\n"));
2447         return;
2448     }
2449     if (rdbSaveBackground(server.dbfilename) == REDIS_OK) {
2450         addReply(c,shared.ok);
2451     } else {
2452         addReply(c,shared.err);
2453     }
2454 }
2455
2456 static void shutdownCommand(redisClient *c) {
2457     redisLog(REDIS_WARNING,"User requested shutdown, saving DB...");
2458     /* XXX: TODO kill the child if there is a bgsave in progress */
2459     if (rdbSave(server.dbfilename) == REDIS_OK) {
2460         if (server.daemonize) {
2461             unlink(server.pidfile);
2462         }
2463         redisLog(REDIS_WARNING,"%zu bytes used at exit",zmalloc_used_memory());
2464         redisLog(REDIS_WARNING,"Server exit now, bye bye...");
2465         exit(1);
2466     } else {
2467         redisLog(REDIS_WARNING,"Error trying to save the DB, can't exit");
2468         addReplySds(c,sdsnew("-ERR can't quit, problems saving the DB\r\n"));
2469     }
2470 }
2471
2472 static void renameGenericCommand(redisClient *c, int nx) {
2473     robj *o;
2474
2475     /* To use the same key as src and dst is probably an error */
2476     if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) {
2477         addReply(c,shared.sameobjecterr);
2478         return;
2479     }
2480
2481     o = lookupKeyWrite(c->db,c->argv[1]);
2482     if (o == NULL) {
2483         addReply(c,shared.nokeyerr);
2484         return;
2485     }
2486     incrRefCount(o);
2487     deleteIfVolatile(c->db,c->argv[2]);
2488     if (dictAdd(c->db->dict,c->argv[2],o) == DICT_ERR) {
2489         if (nx) {
2490             decrRefCount(o);
2491             addReply(c,shared.czero);
2492             return;
2493         }
2494         dictReplace(c->db->dict,c->argv[2],o);
2495     } else {
2496         incrRefCount(c->argv[2]);
2497     }
2498     deleteKey(c->db,c->argv[1]);
2499     server.dirty++;
2500     addReply(c,nx ? shared.cone : shared.ok);
2501 }
2502
2503 static void renameCommand(redisClient *c) {
2504     renameGenericCommand(c,0);
2505 }
2506
2507 static void renamenxCommand(redisClient *c) {
2508     renameGenericCommand(c,1);
2509 }
2510
2511 static void moveCommand(redisClient *c) {
2512     robj *o;
2513     redisDb *src, *dst;
2514     int srcid;
2515
2516     /* Obtain source and target DB pointers */
2517     src = c->db;
2518     srcid = c->db->id;
2519     if (selectDb(c,atoi(c->argv[2]->ptr)) == REDIS_ERR) {
2520         addReply(c,shared.outofrangeerr);
2521         return;
2522     }
2523     dst = c->db;
2524     selectDb(c,srcid); /* Back to the source DB */
2525
2526     /* If the user is moving using as target the same
2527      * DB as the source DB it is probably an error. */
2528     if (src == dst) {
2529         addReply(c,shared.sameobjecterr);
2530         return;
2531     }
2532
2533     /* Check if the element exists and get a reference */
2534     o = lookupKeyWrite(c->db,c->argv[1]);
2535     if (!o) {
2536         addReply(c,shared.czero);
2537         return;
2538     }
2539
2540     /* Try to add the element to the target DB */
2541     deleteIfVolatile(dst,c->argv[1]);
2542     if (dictAdd(dst->dict,c->argv[1],o) == DICT_ERR) {
2543         addReply(c,shared.czero);
2544         return;
2545     }
2546     incrRefCount(c->argv[1]);
2547     incrRefCount(o);
2548
2549     /* OK! key moved, free the entry in the source DB */
2550     deleteKey(src,c->argv[1]);
2551     server.dirty++;
2552     addReply(c,shared.cone);
2553 }
2554
2555 /* =================================== Lists ================================ */
2556 static void pushGenericCommand(redisClient *c, int where) {
2557     robj *lobj;
2558     list *list;
2559
2560     lobj = lookupKeyWrite(c->db,c->argv[1]);
2561     if (lobj == NULL) {
2562         lobj = createListObject();
2563         list = lobj->ptr;
2564         if (where == REDIS_HEAD) {
2565             if (!listAddNodeHead(list,c->argv[2])) oom("listAddNodeHead");
2566         } else {
2567             if (!listAddNodeTail(list,c->argv[2])) oom("listAddNodeTail");
2568         }
2569         dictAdd(c->db->dict,c->argv[1],lobj);
2570         incrRefCount(c->argv[1]);
2571         incrRefCount(c->argv[2]);
2572     } else {
2573         if (lobj->type != REDIS_LIST) {
2574             addReply(c,shared.wrongtypeerr);
2575             return;
2576         }
2577         list = lobj->ptr;
2578         if (where == REDIS_HEAD) {
2579             if (!listAddNodeHead(list,c->argv[2])) oom("listAddNodeHead");
2580         } else {
2581             if (!listAddNodeTail(list,c->argv[2])) oom("listAddNodeTail");
2582         }
2583         incrRefCount(c->argv[2]);
2584     }
2585     server.dirty++;
2586     addReply(c,shared.ok);
2587 }
2588
2589 static void lpushCommand(redisClient *c) {
2590     pushGenericCommand(c,REDIS_HEAD);
2591 }
2592
2593 static void rpushCommand(redisClient *c) {
2594     pushGenericCommand(c,REDIS_TAIL);
2595 }
2596
2597 static void llenCommand(redisClient *c) {
2598     robj *o;
2599     list *l;
2600
2601     o = lookupKeyRead(c->db,c->argv[1]);
2602     if (o == NULL) {
2603         addReply(c,shared.czero);
2604         return;
2605     } else {
2606         if (o->type != REDIS_LIST) {
2607             addReply(c,shared.wrongtypeerr);
2608         } else {
2609             l = o->ptr;
2610             addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",listLength(l)));
2611         }
2612     }
2613 }
2614
2615 static void lindexCommand(redisClient *c) {
2616     robj *o;
2617     int index = atoi(c->argv[2]->ptr);
2618
2619     o = lookupKeyRead(c->db,c->argv[1]);
2620     if (o == NULL) {
2621         addReply(c,shared.nullbulk);
2622     } else {
2623         if (o->type != REDIS_LIST) {
2624             addReply(c,shared.wrongtypeerr);
2625         } else {
2626             list *list = o->ptr;
2627             listNode *ln;
2628
2629             ln = listIndex(list, index);
2630             if (ln == NULL) {
2631                 addReply(c,shared.nullbulk);
2632             } else {
2633                 robj *ele = listNodeValue(ln);
2634                 addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(ele->ptr)));
2635                 addReply(c,ele);
2636                 addReply(c,shared.crlf);
2637             }
2638         }
2639     }
2640 }
2641
2642 static void lsetCommand(redisClient *c) {
2643     robj *o;
2644     int index = atoi(c->argv[2]->ptr);
2645
2646     o = lookupKeyWrite(c->db,c->argv[1]);
2647     if (o == NULL) {
2648         addReply(c,shared.nokeyerr);
2649     } else {
2650         if (o->type != REDIS_LIST) {
2651             addReply(c,shared.wrongtypeerr);
2652         } else {
2653             list *list = o->ptr;
2654             listNode *ln;
2655
2656             ln = listIndex(list, index);
2657             if (ln == NULL) {
2658                 addReply(c,shared.outofrangeerr);
2659             } else {
2660                 robj *ele = listNodeValue(ln);
2661
2662                 decrRefCount(ele);
2663                 listNodeValue(ln) = c->argv[3];
2664                 incrRefCount(c->argv[3]);
2665                 addReply(c,shared.ok);
2666                 server.dirty++;
2667             }
2668         }
2669     }
2670 }
2671
2672 static void popGenericCommand(redisClient *c, int where) {
2673     robj *o;
2674
2675     o = lookupKeyWrite(c->db,c->argv[1]);
2676     if (o == NULL) {
2677         addReply(c,shared.nullbulk);
2678     } else {
2679         if (o->type != REDIS_LIST) {
2680             addReply(c,shared.wrongtypeerr);
2681         } else {
2682             list *list = o->ptr;
2683             listNode *ln;
2684
2685             if (where == REDIS_HEAD)
2686                 ln = listFirst(list);
2687             else
2688                 ln = listLast(list);
2689
2690             if (ln == NULL) {
2691                 addReply(c,shared.nullbulk);
2692             } else {
2693                 robj *ele = listNodeValue(ln);
2694                 addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(ele->ptr)));
2695                 addReply(c,ele);
2696                 addReply(c,shared.crlf);
2697                 listDelNode(list,ln);
2698                 server.dirty++;
2699             }
2700         }
2701     }
2702 }
2703
2704 static void lpopCommand(redisClient *c) {
2705     popGenericCommand(c,REDIS_HEAD);
2706 }
2707
2708 static void rpopCommand(redisClient *c) {
2709     popGenericCommand(c,REDIS_TAIL);
2710 }
2711
2712 static void lrangeCommand(redisClient *c) {
2713     robj *o;
2714     int start = atoi(c->argv[2]->ptr);
2715     int end = atoi(c->argv[3]->ptr);
2716
2717     o = lookupKeyRead(c->db,c->argv[1]);
2718     if (o == NULL) {
2719         addReply(c,shared.nullmultibulk);
2720     } else {
2721         if (o->type != REDIS_LIST) {
2722             addReply(c,shared.wrongtypeerr);
2723         } else {
2724             list *list = o->ptr;
2725             listNode *ln;
2726             int llen = listLength(list);
2727             int rangelen, j;
2728             robj *ele;
2729
2730             /* convert negative indexes */
2731             if (start < 0) start = llen+start;
2732             if (end < 0) end = llen+end;
2733             if (start < 0) start = 0;
2734             if (end < 0) end = 0;
2735
2736             /* indexes sanity checks */
2737             if (start > end || start >= llen) {
2738                 /* Out of range start or start > end result in empty list */
2739                 addReply(c,shared.emptymultibulk);
2740                 return;
2741             }
2742             if (end >= llen) end = llen-1;
2743             rangelen = (end-start)+1;
2744
2745             /* Return the result in form of a multi-bulk reply */
2746             ln = listIndex(list, start);
2747             addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",rangelen));
2748             for (j = 0; j < rangelen; j++) {
2749                 ele = listNodeValue(ln);
2750                 addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",(int)sdslen(ele->ptr)));
2751                 addReply(c,ele);
2752                 addReply(c,shared.crlf);
2753                 ln = ln->next;
2754             }
2755         }
2756     }
2757 }
2758
2759 static void ltrimCommand(redisClient *c) {
2760     robj *o;
2761     int start = atoi(c->argv[2]->ptr);
2762     int end = atoi(c->argv[3]->ptr);
2763
2764     o = lookupKeyWrite(c->db,c->argv[1]);
2765     if (o == NULL) {
2766         addReply(c,shared.nokeyerr);
2767     } else {
2768         if (o->type != REDIS_LIST) {
2769             addReply(c,shared.wrongtypeerr);
2770         } else {
2771             list *list = o->ptr;
2772             listNode *ln;
2773             int llen = listLength(list);
2774             int j, ltrim, rtrim;
2775
2776             /* convert negative indexes */
2777             if (start < 0) start = llen+start;
2778             if (end < 0) end = llen+end;
2779             if (start < 0) start = 0;
2780             if (end < 0) end = 0;
2781
2782             /* indexes sanity checks */
2783             if (start > end || start >= llen) {
2784                 /* Out of range start or start > end result in empty list */
2785                 ltrim = llen;
2786                 rtrim = 0;
2787             } else {
2788                 if (end >= llen) end = llen-1;
2789                 ltrim = start;
2790                 rtrim = llen-end-1;
2791             }
2792
2793             /* Remove list elements to perform the trim */
2794             for (j = 0; j < ltrim; j++) {
2795                 ln = listFirst(list);
2796                 listDelNode(list,ln);
2797             }
2798             for (j = 0; j < rtrim; j++) {
2799                 ln = listLast(list);
2800                 listDelNode(list,ln);
2801             }
2802             addReply(c,shared.ok);
2803             server.dirty++;
2804         }
2805     }
2806 }
2807
2808 static void lremCommand(redisClient *c) {
2809     robj *o;
2810
2811     o = lookupKeyWrite(c->db,c->argv[1]);
2812     if (o == NULL) {
2813         addReply(c,shared.nokeyerr);
2814     } else {
2815         if (o->type != REDIS_LIST) {
2816             addReply(c,shared.wrongtypeerr);
2817         } else {
2818             list *list = o->ptr;
2819             listNode *ln, *next;
2820             int toremove = atoi(c->argv[2]->ptr);
2821             int removed = 0;
2822             int fromtail = 0;
2823
2824             if (toremove < 0) {
2825                 toremove = -toremove;
2826                 fromtail = 1;
2827             }
2828             ln = fromtail ? list->tail : list->head;
2829             while (ln) {
2830                 robj *ele = listNodeValue(ln);
2831
2832                 next = fromtail ? ln->prev : ln->next;
2833                 if (sdscmp(ele->ptr,c->argv[3]->ptr) == 0) {
2834                     listDelNode(list,ln);
2835                     server.dirty++;
2836                     removed++;
2837                     if (toremove && removed == toremove) break;
2838                 }
2839                 ln = next;
2840             }
2841             addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",removed));
2842         }
2843     }
2844 }
2845
2846 /* ==================================== Sets ================================ */
2847
2848 static void saddCommand(redisClient *c) {
2849     robj *set;
2850
2851     set = lookupKeyWrite(c->db,c->argv[1]);
2852     if (set == NULL) {
2853         set = createSetObject();
2854         dictAdd(c->db->dict,c->argv[1],set);
2855         incrRefCount(c->argv[1]);
2856     } else {
2857         if (set->type != REDIS_SET) {
2858             addReply(c,shared.wrongtypeerr);
2859             return;
2860         }
2861     }
2862     if (dictAdd(set->ptr,c->argv[2],NULL) == DICT_OK) {
2863         incrRefCount(c->argv[2]);
2864         server.dirty++;
2865         addReply(c,shared.cone);
2866     } else {
2867         addReply(c,shared.czero);
2868     }
2869 }
2870
2871 static void sremCommand(redisClient *c) {
2872     robj *set;
2873
2874     set = lookupKeyWrite(c->db,c->argv[1]);
2875     if (set == NULL) {
2876         addReply(c,shared.czero);
2877     } else {
2878         if (set->type != REDIS_SET) {
2879             addReply(c,shared.wrongtypeerr);
2880             return;
2881         }
2882         if (dictDelete(set->ptr,c->argv[2]) == DICT_OK) {
2883             server.dirty++;
2884             addReply(c,shared.cone);
2885         } else {
2886             addReply(c,shared.czero);
2887         }
2888     }
2889 }
2890
2891 static void smoveCommand(redisClient *c) {
2892     robj *srcset, *dstset;
2893
2894     srcset = lookupKeyWrite(c->db,c->argv[1]);
2895     dstset = lookupKeyWrite(c->db,c->argv[2]);
2896
2897     /* If the source key does not exist return 0, if it's of the wrong type
2898      * raise an error */
2899     if (srcset == NULL || srcset->type != REDIS_SET) {
2900         addReply(c, srcset ? shared.wrongtypeerr : shared.czero);
2901         return;
2902     }
2903     /* Error if the destination key is not a set as well */
2904     if (dstset && dstset->type != REDIS_SET) {
2905         addReply(c,shared.wrongtypeerr);
2906         return;
2907     }
2908     /* Remove the element from the source set */
2909     if (dictDelete(srcset->ptr,c->argv[3]) == DICT_ERR) {
2910         /* Key not found in the src set! return zero */
2911         addReply(c,shared.czero);
2912         return;
2913     }
2914     server.dirty++;
2915     /* Add the element to the destination set */
2916     if (!dstset) {
2917         dstset = createSetObject();
2918         dictAdd(c->db->dict,c->argv[2],dstset);
2919         incrRefCount(c->argv[2]);
2920     }
2921     if (dictAdd(dstset->ptr,c->argv[3],NULL) == DICT_OK)
2922         incrRefCount(c->argv[3]);
2923     addReply(c,shared.cone);
2924 }
2925
2926 static void sismemberCommand(redisClient *c) {
2927     robj *set;
2928
2929     set = lookupKeyRead(c->db,c->argv[1]);
2930     if (set == NULL) {
2931         addReply(c,shared.czero);
2932     } else {
2933         if (set->type != REDIS_SET) {
2934             addReply(c,shared.wrongtypeerr);
2935             return;
2936         }
2937         if (dictFind(set->ptr,c->argv[2]))
2938             addReply(c,shared.cone);
2939         else
2940             addReply(c,shared.czero);
2941     }
2942 }
2943
2944 static void scardCommand(redisClient *c) {
2945     robj *o;
2946     dict *s;
2947
2948     o = lookupKeyRead(c->db,c->argv[1]);
2949     if (o == NULL) {
2950         addReply(c,shared.czero);
2951         return;
2952     } else {
2953         if (o->type != REDIS_SET) {
2954             addReply(c,shared.wrongtypeerr);
2955         } else {
2956             s = o->ptr;
2957             addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",
2958                 dictSize(s)));
2959         }
2960     }
2961 }
2962
2963 static int qsortCompareSetsByCardinality(const void *s1, const void *s2) {
2964     dict **d1 = (void*) s1, **d2 = (void*) s2;
2965
2966     return dictSize(*d1)-dictSize(*d2);
2967 }
2968
2969 static void sinterGenericCommand(redisClient *c, robj **setskeys, int setsnum, robj *dstkey) {
2970     dict **dv = zmalloc(sizeof(dict*)*setsnum);
2971     dictIterator *di;
2972     dictEntry *de;
2973     robj *lenobj = NULL, *dstset = NULL;
2974     int j, cardinality = 0;
2975
2976     if (!dv) oom("sinterCommand");
2977     for (j = 0; j < setsnum; j++) {
2978         robj *setobj;
2979
2980         setobj = dstkey ?
2981                     lookupKeyWrite(c->db,setskeys[j]) :
2982                     lookupKeyRead(c->db,setskeys[j]);
2983         if (!setobj) {
2984             zfree(dv);
2985             if (dstkey) {
2986                 deleteKey(c->db,dstkey);
2987                 addReply(c,shared.ok);
2988             } else {
2989                 addReply(c,shared.nullmultibulk);
2990             }
2991             return;
2992         }
2993         if (setobj->type != REDIS_SET) {
2994             zfree(dv);
2995             addReply(c,shared.wrongtypeerr);
2996             return;
2997         }
2998         dv[j] = setobj->ptr;
2999     }
3000     /* Sort sets from the smallest to largest, this will improve our
3001      * algorithm's performace */
3002     qsort(dv,setsnum,sizeof(dict*),qsortCompareSetsByCardinality);
3003
3004     /* The first thing we should output is the total number of elements...
3005      * since this is a multi-bulk write, but at this stage we don't know
3006      * the intersection set size, so we use a trick, append an empty object
3007      * to the output list and save the pointer to later modify it with the
3008      * right length */
3009     if (!dstkey) {
3010         lenobj = createObject(REDIS_STRING,NULL);
3011         addReply(c,lenobj);
3012         decrRefCount(lenobj);
3013     } else {
3014         /* If we have a target key where to store the resulting set
3015          * create this key with an empty set inside */
3016         dstset = createSetObject();
3017     }
3018
3019     /* Iterate all the elements of the first (smallest) set, and test
3020      * the element against all the other sets, if at least one set does
3021      * not include the element it is discarded */
3022     di = dictGetIterator(dv[0]);
3023     if (!di) oom("dictGetIterator");
3024
3025     while((de = dictNext(di)) != NULL) {
3026         robj *ele;
3027
3028         for (j = 1; j < setsnum; j++)
3029             if (dictFind(dv[j],dictGetEntryKey(de)) == NULL) break;
3030         if (j != setsnum)
3031             continue; /* at least one set does not contain the member */
3032         ele = dictGetEntryKey(de);
3033         if (!dstkey) {
3034             addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",sdslen(ele->ptr)));
3035             addReply(c,ele);
3036             addReply(c,shared.crlf);
3037             cardinality++;
3038         } else {
3039             dictAdd(dstset->ptr,ele,NULL);
3040             incrRefCount(ele);
3041         }
3042     }
3043     dictReleaseIterator(di);
3044
3045     if (dstkey) {
3046         /* Store the resulting set into the target */
3047         deleteKey(c->db,dstkey);
3048         dictAdd(c->db->dict,dstkey,dstset);
3049         incrRefCount(dstkey);
3050     }
3051
3052     if (!dstkey) {
3053         lenobj->ptr = sdscatprintf(sdsempty(),"*%d\r\n",cardinality);
3054     } else {
3055         addReply(c,shared.ok);
3056         server.dirty++;
3057     }
3058     zfree(dv);
3059 }
3060
3061 static void sinterCommand(redisClient *c) {
3062     sinterGenericCommand(c,c->argv+1,c->argc-1,NULL);
3063 }
3064
3065 static void sinterstoreCommand(redisClient *c) {
3066     sinterGenericCommand(c,c->argv+2,c->argc-2,c->argv[1]);
3067 }
3068
3069 #define REDIS_OP_UNION 0
3070 #define REDIS_OP_DIFF 1
3071
3072 static void sunionDiffGenericCommand(redisClient *c, robj **setskeys, int setsnum, robj *dstkey, int op) {
3073     dict **dv = zmalloc(sizeof(dict*)*setsnum);
3074     dictIterator *di;
3075     dictEntry *de;
3076     robj *dstset = NULL;
3077     int j, cardinality = 0;
3078
3079     if (!dv) oom("sunionDiffGenericCommand");
3080     for (j = 0; j < setsnum; j++) {
3081         robj *setobj;
3082
3083         setobj = dstkey ?
3084                     lookupKeyWrite(c->db,setskeys[j]) :
3085                     lookupKeyRead(c->db,setskeys[j]);
3086         if (!setobj) {
3087             dv[j] = NULL;
3088             continue;
3089         }
3090         if (setobj->type != REDIS_SET) {
3091             zfree(dv);
3092             addReply(c,shared.wrongtypeerr);
3093             return;
3094         }
3095         dv[j] = setobj->ptr;
3096     }
3097
3098     /* We need a temp set object to store our union. If the dstkey
3099      * is not NULL (that is, we are inside an SUNIONSTORE operation) then
3100      * this set object will be the resulting object to set into the target key*/
3101     dstset = createSetObject();
3102
3103     /* Iterate all the elements of all the sets, add every element a single
3104      * time to the result set */
3105     for (j = 0; j < setsnum; j++) {
3106         if (op == REDIS_OP_DIFF && j == 0 && !dv[j]) break; /* result set is empty */
3107         if (!dv[j]) continue; /* non existing keys are like empty sets */
3108
3109         di = dictGetIterator(dv[j]);
3110         if (!di) oom("dictGetIterator");
3111
3112         while((de = dictNext(di)) != NULL) {
3113             robj *ele;
3114
3115             /* dictAdd will not add the same element multiple times */
3116             ele = dictGetEntryKey(de);
3117             if (op == REDIS_OP_UNION || j == 0) {
3118                 if (dictAdd(dstset->ptr,ele,NULL) == DICT_OK) {
3119                     incrRefCount(ele);
3120                     cardinality++;
3121                 }
3122             } else if (op == REDIS_OP_DIFF) {
3123                 if (dictDelete(dstset->ptr,ele) == DICT_OK) {
3124                     cardinality--;
3125                 }
3126             }
3127         }
3128         dictReleaseIterator(di);
3129
3130         if (op == REDIS_OP_DIFF && cardinality == 0) break; /* result set is empty */
3131     }
3132
3133     /* Output the content of the resulting set, if not in STORE mode */
3134     if (!dstkey) {
3135         addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",cardinality));
3136         di = dictGetIterator(dstset->ptr);
3137         if (!di) oom("dictGetIterator");
3138         while((de = dictNext(di)) != NULL) {
3139             robj *ele;
3140
3141             ele = dictGetEntryKey(de);
3142             addReplySds(c,sdscatprintf(sdsempty(),
3143                     "$%d\r\n",sdslen(ele->ptr)));
3144             addReply(c,ele);
3145             addReply(c,shared.crlf);
3146         }
3147         dictReleaseIterator(di);
3148     } else {
3149         /* If we have a target key where to store the resulting set
3150          * create this key with the result set inside */
3151         deleteKey(c->db,dstkey);
3152         dictAdd(c->db->dict,dstkey,dstset);
3153         incrRefCount(dstkey);
3154         server.dirty++;
3155     }
3156
3157     /* Cleanup */
3158     if (!dstkey) {
3159         decrRefCount(dstset);
3160     } else {
3161         addReply(c,shared.ok);
3162         server.dirty++;
3163     }
3164     zfree(dv);
3165 }
3166
3167 static void sunionCommand(redisClient *c) {
3168     sunionDiffGenericCommand(c,c->argv+1,c->argc-1,NULL,REDIS_OP_UNION);
3169 }
3170
3171 static void sunionstoreCommand(redisClient *c) {
3172     sunionDiffGenericCommand(c,c->argv+2,c->argc-2,c->argv[1],REDIS_OP_UNION);
3173 }
3174
3175 static void sdiffCommand(redisClient *c) {
3176     sunionDiffGenericCommand(c,c->argv+1,c->argc-1,NULL,REDIS_OP_DIFF);
3177 }
3178
3179 static void sdiffstoreCommand(redisClient *c) {
3180     sunionDiffGenericCommand(c,c->argv+2,c->argc-2,c->argv[1],REDIS_OP_DIFF);
3181 }
3182
3183 static void flushdbCommand(redisClient *c) {
3184     server.dirty += dictSize(c->db->dict);
3185     dictEmpty(c->db->dict);
3186     dictEmpty(c->db->expires);
3187     addReply(c,shared.ok);
3188 }
3189
3190 static void flushallCommand(redisClient *c) {
3191     server.dirty += emptyDb();
3192     addReply(c,shared.ok);
3193     rdbSave(server.dbfilename);
3194     server.dirty++;
3195 }
3196
3197 redisSortOperation *createSortOperation(int type, robj *pattern) {
3198     redisSortOperation *so = zmalloc(sizeof(*so));
3199     if (!so) oom("createSortOperation");
3200     so->type = type;
3201     so->pattern = pattern;
3202     return so;
3203 }
3204
3205 /* Return the value associated to the key with a name obtained
3206  * substituting the first occurence of '*' in 'pattern' with 'subst' */
3207 robj *lookupKeyByPattern(redisDb *db, robj *pattern, robj *subst) {
3208     char *p;
3209     sds spat, ssub;
3210     robj keyobj;
3211     int prefixlen, sublen, postfixlen;
3212     /* Expoit the internal sds representation to create a sds string allocated on the stack in order to make this function faster */
3213     struct {
3214         long len;
3215         long free;
3216         char buf[REDIS_SORTKEY_MAX+1];
3217     } keyname;
3218
3219     spat = pattern->ptr;
3220     ssub = subst->ptr;
3221     if (sdslen(spat)+sdslen(ssub)-1 > REDIS_SORTKEY_MAX) return NULL;
3222     p = strchr(spat,'*');
3223     if (!p) return NULL;
3224
3225     prefixlen = p-spat;
3226     sublen = sdslen(ssub);
3227     postfixlen = sdslen(spat)-(prefixlen+1);
3228     memcpy(keyname.buf,spat,prefixlen);
3229     memcpy(keyname.buf+prefixlen,ssub,sublen);
3230     memcpy(keyname.buf+prefixlen+sublen,p+1,postfixlen);
3231     keyname.buf[prefixlen+sublen+postfixlen] = '\0';
3232     keyname.len = prefixlen+sublen+postfixlen;
3233
3234     keyobj.refcount = 1;
3235     keyobj.type = REDIS_STRING;
3236     keyobj.ptr = ((char*)&keyname)+(sizeof(long)*2);
3237
3238     /* printf("lookup '%s' => %p\n", keyname.buf,de); */
3239     return lookupKeyRead(db,&keyobj);
3240 }
3241
3242 /* sortCompare() is used by qsort in sortCommand(). Given that qsort_r with
3243  * the additional parameter is not standard but a BSD-specific we have to
3244  * pass sorting parameters via the global 'server' structure */
3245 static int sortCompare(const void *s1, const void *s2) {
3246     const redisSortObject *so1 = s1, *so2 = s2;
3247     int cmp;
3248
3249     if (!server.sort_alpha) {
3250         /* Numeric sorting. Here it's trivial as we precomputed scores */
3251         if (so1->u.score > so2->u.score) {
3252             cmp = 1;
3253         } else if (so1->u.score < so2->u.score) {
3254             cmp = -1;
3255         } else {
3256             cmp = 0;
3257         }
3258     } else {
3259         /* Alphanumeric sorting */
3260         if (server.sort_bypattern) {
3261             if (!so1->u.cmpobj || !so2->u.cmpobj) {
3262                 /* At least one compare object is NULL */
3263                 if (so1->u.cmpobj == so2->u.cmpobj)
3264                     cmp = 0;
3265                 else if (so1->u.cmpobj == NULL)
3266                     cmp = -1;
3267                 else
3268                     cmp = 1;
3269             } else {
3270                 /* We have both the objects, use strcoll */
3271                 cmp = strcoll(so1->u.cmpobj->ptr,so2->u.cmpobj->ptr);
3272             }
3273         } else {
3274             /* Compare elements directly */
3275             cmp = strcoll(so1->obj->ptr,so2->obj->ptr);
3276         }
3277     }
3278     return server.sort_desc ? -cmp : cmp;
3279 }
3280
3281 /* The SORT command is the most complex command in Redis. Warning: this code
3282  * is optimized for speed and a bit less for readability */
3283 static void sortCommand(redisClient *c) {
3284     list *operations;
3285     int outputlen = 0;
3286     int desc = 0, alpha = 0;
3287     int limit_start = 0, limit_count = -1, start, end;
3288     int j, dontsort = 0, vectorlen;
3289     int getop = 0; /* GET operation counter */
3290     robj *sortval, *sortby = NULL;
3291     redisSortObject *vector; /* Resulting vector to sort */
3292
3293     /* Lookup the key to sort. It must be of the right types */
3294     sortval = lookupKeyRead(c->db,c->argv[1]);
3295     if (sortval == NULL) {
3296         addReply(c,shared.nokeyerr);
3297         return;
3298     }
3299     if (sortval->type != REDIS_SET && sortval->type != REDIS_LIST) {
3300         addReply(c,shared.wrongtypeerr);
3301         return;
3302     }
3303
3304     /* Create a list of operations to perform for every sorted element.
3305      * Operations can be GET/DEL/INCR/DECR */
3306     operations = listCreate();
3307     listSetFreeMethod(operations,zfree);
3308     j = 2;
3309
3310     /* Now we need to protect sortval incrementing its count, in the future
3311      * SORT may have options able to overwrite/delete keys during the sorting
3312      * and the sorted key itself may get destroied */
3313     incrRefCount(sortval);
3314
3315     /* The SORT command has an SQL-alike syntax, parse it */
3316     while(j < c->argc) {
3317         int leftargs = c->argc-j-1;
3318         if (!strcasecmp(c->argv[j]->ptr,"asc")) {
3319             desc = 0;
3320         } else if (!strcasecmp(c->argv[j]->ptr,"desc")) {
3321             desc = 1;
3322         } else if (!strcasecmp(c->argv[j]->ptr,"alpha")) {
3323             alpha = 1;
3324         } else if (!strcasecmp(c->argv[j]->ptr,"limit") && leftargs >= 2) {
3325             limit_start = atoi(c->argv[j+1]->ptr);
3326             limit_count = atoi(c->argv[j+2]->ptr);
3327             j+=2;
3328         } else if (!strcasecmp(c->argv[j]->ptr,"by") && leftargs >= 1) {
3329             sortby = c->argv[j+1];
3330             /* If the BY pattern does not contain '*', i.e. it is constant,
3331              * we don't need to sort nor to lookup the weight keys. */
3332             if (strchr(c->argv[j+1]->ptr,'*') == NULL) dontsort = 1;
3333             j++;
3334         } else if (!strcasecmp(c->argv[j]->ptr,"get") && leftargs >= 1) {
3335             listAddNodeTail(operations,createSortOperation(
3336                 REDIS_SORT_GET,c->argv[j+1]));
3337             getop++;
3338             j++;
3339         } else if (!strcasecmp(c->argv[j]->ptr,"del") && leftargs >= 1) {
3340             listAddNodeTail(operations,createSortOperation(
3341                 REDIS_SORT_DEL,c->argv[j+1]));
3342             j++;
3343         } else if (!strcasecmp(c->argv[j]->ptr,"incr") && leftargs >= 1) {
3344             listAddNodeTail(operations,createSortOperation(
3345                 REDIS_SORT_INCR,c->argv[j+1]));
3346             j++;
3347         } else if (!strcasecmp(c->argv[j]->ptr,"get") && leftargs >= 1) {
3348             listAddNodeTail(operations,createSortOperation(
3349                 REDIS_SORT_DECR,c->argv[j+1]));
3350             j++;
3351         } else {
3352             decrRefCount(sortval);
3353             listRelease(operations);
3354             addReply(c,shared.syntaxerr);
3355             return;
3356         }
3357         j++;
3358     }
3359
3360     /* Load the sorting vector with all the objects to sort */
3361     vectorlen = (sortval->type == REDIS_LIST) ?
3362         listLength((list*)sortval->ptr) :
3363         dictSize((dict*)sortval->ptr);
3364     vector = zmalloc(sizeof(redisSortObject)*vectorlen);
3365     if (!vector) oom("allocating objects vector for SORT");
3366     j = 0;
3367     if (sortval->type == REDIS_LIST) {
3368         list *list = sortval->ptr;
3369         listNode *ln;
3370
3371         listRewind(list);
3372         while((ln = listYield(list))) {
3373             robj *ele = ln->value;
3374             vector[j].obj = ele;
3375             vector[j].u.score = 0;
3376             vector[j].u.cmpobj = NULL;
3377             j++;
3378         }
3379     } else {
3380         dict *set = sortval->ptr;
3381         dictIterator *di;
3382         dictEntry *setele;
3383
3384         di = dictGetIterator(set);
3385         if (!di) oom("dictGetIterator");
3386         while((setele = dictNext(di)) != NULL) {
3387             vector[j].obj = dictGetEntryKey(setele);
3388             vector[j].u.score = 0;
3389             vector[j].u.cmpobj = NULL;
3390             j++;
3391         }
3392         dictReleaseIterator(di);
3393     }
3394     assert(j == vectorlen);
3395
3396     /* Now it's time to load the right scores in the sorting vector */
3397     if (dontsort == 0) {
3398         for (j = 0; j < vectorlen; j++) {
3399             if (sortby) {
3400                 robj *byval;
3401
3402                 byval = lookupKeyByPattern(c->db,sortby,vector[j].obj);
3403                 if (!byval || byval->type != REDIS_STRING) continue;
3404                 if (alpha) {
3405                     vector[j].u.cmpobj = byval;
3406                     incrRefCount(byval);
3407                 } else {
3408                     vector[j].u.score = strtod(byval->ptr,NULL);
3409                 }
3410             } else {
3411                 if (!alpha) vector[j].u.score = strtod(vector[j].obj->ptr,NULL);
3412             }
3413         }
3414     }
3415
3416     /* We are ready to sort the vector... perform a bit of sanity check
3417      * on the LIMIT option too. We'll use a partial version of quicksort. */
3418     start = (limit_start < 0) ? 0 : limit_start;
3419     end = (limit_count < 0) ? vectorlen-1 : start+limit_count-1;
3420     if (start >= vectorlen) {
3421         start = vectorlen-1;
3422         end = vectorlen-2;
3423     }
3424     if (end >= vectorlen) end = vectorlen-1;
3425
3426     if (dontsort == 0) {
3427         server.sort_desc = desc;
3428         server.sort_alpha = alpha;
3429         server.sort_bypattern = sortby ? 1 : 0;
3430         if (sortby && (start != 0 || end != vectorlen-1))
3431             pqsort(vector,vectorlen,sizeof(redisSortObject),sortCompare, start,end);
3432         else
3433             qsort(vector,vectorlen,sizeof(redisSortObject),sortCompare);
3434     }
3435
3436     /* Send command output to the output buffer, performing the specified
3437      * GET/DEL/INCR/DECR operations if any. */
3438     outputlen = getop ? getop*(end-start+1) : end-start+1;
3439     addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",outputlen));
3440     for (j = start; j <= end; j++) {
3441         listNode *ln;
3442         if (!getop) {
3443             addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",
3444                 sdslen(vector[j].obj->ptr)));
3445             addReply(c,vector[j].obj);
3446             addReply(c,shared.crlf);
3447         }
3448         listRewind(operations);
3449         while((ln = listYield(operations))) {
3450             redisSortOperation *sop = ln->value;
3451             robj *val = lookupKeyByPattern(c->db,sop->pattern,
3452                 vector[j].obj);
3453
3454             if (sop->type == REDIS_SORT_GET) {
3455                 if (!val || val->type != REDIS_STRING) {
3456                     addReply(c,shared.nullbulk);
3457                 } else {
3458                     addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",
3459                         sdslen(val->ptr)));
3460                     addReply(c,val);
3461                     addReply(c,shared.crlf);
3462                 }
3463             } else if (sop->type == REDIS_SORT_DEL) {
3464                 /* TODO */
3465             }
3466         }
3467     }
3468
3469     /* Cleanup */
3470     decrRefCount(sortval);
3471     listRelease(operations);
3472     for (j = 0; j < vectorlen; j++) {
3473         if (sortby && alpha && vector[j].u.cmpobj)
3474             decrRefCount(vector[j].u.cmpobj);
3475     }
3476     zfree(vector);
3477 }
3478
3479 static void infoCommand(redisClient *c) {
3480     sds info;
3481     time_t uptime = time(NULL)-server.stat_starttime;
3482
3483     info = sdscatprintf(sdsempty(),
3484         "redis_version:%s\r\n"
3485         "connected_clients:%d\r\n"
3486         "connected_slaves:%d\r\n"
3487         "used_memory:%zu\r\n"
3488         "changes_since_last_save:%lld\r\n"
3489         "bgsave_in_progress:%d\r\n"
3490         "last_save_time:%d\r\n"
3491         "total_connections_received:%lld\r\n"
3492         "total_commands_processed:%lld\r\n"
3493         "uptime_in_seconds:%d\r\n"
3494         "uptime_in_days:%d\r\n"
3495         ,REDIS_VERSION,
3496         listLength(server.clients)-listLength(server.slaves),
3497         listLength(server.slaves),
3498         server.usedmemory,
3499         server.dirty,
3500         server.bgsaveinprogress,
3501         server.lastsave,
3502         server.stat_numconnections,
3503         server.stat_numcommands,
3504         uptime,
3505         uptime/(3600*24)
3506     );
3507     addReplySds(c,sdscatprintf(sdsempty(),"$%d\r\n",sdslen(info)));
3508     addReplySds(c,info);
3509     addReply(c,shared.crlf);
3510 }
3511
3512 static void monitorCommand(redisClient *c) {
3513     /* ignore MONITOR if aleady slave or in monitor mode */
3514     if (c->flags & REDIS_SLAVE) return;
3515
3516     c->flags |= (REDIS_SLAVE|REDIS_MONITOR);
3517     c->slaveseldb = 0;
3518     if (!listAddNodeTail(server.monitors,c)) oom("listAddNodeTail");
3519     addReply(c,shared.ok);
3520 }
3521
3522 /* ================================= Expire ================================= */
3523 static int removeExpire(redisDb *db, robj *key) {
3524     if (dictDelete(db->expires,key) == DICT_OK) {
3525         return 1;
3526     } else {
3527         return 0;
3528     }
3529 }
3530
3531 static int setExpire(redisDb *db, robj *key, time_t when) {
3532     if (dictAdd(db->expires,key,(void*)when) == DICT_ERR) {
3533         return 0;
3534     } else {
3535         incrRefCount(key);
3536         return 1;
3537     }
3538 }
3539
3540 /* Return the expire time of the specified key, or -1 if no expire
3541  * is associated with this key (i.e. the key is non volatile) */
3542 static time_t getExpire(redisDb *db, robj *key) {
3543     dictEntry *de;
3544
3545     /* No expire? return ASAP */
3546     if (dictSize(db->expires) == 0 ||
3547        (de = dictFind(db->expires,key)) == NULL) return -1;
3548
3549     return (time_t) dictGetEntryVal(de);
3550 }
3551
3552 static int expireIfNeeded(redisDb *db, robj *key) {
3553     time_t when;
3554     dictEntry *de;
3555
3556     /* No expire? return ASAP */
3557     if (dictSize(db->expires) == 0 ||
3558        (de = dictFind(db->expires,key)) == NULL) return 0;
3559
3560     /* Lookup the expire */
3561     when = (time_t) dictGetEntryVal(de);
3562     if (time(NULL) <= when) return 0;
3563
3564     /* Delete the key */
3565     dictDelete(db->expires,key);
3566     return dictDelete(db->dict,key) == DICT_OK;
3567 }
3568
3569 static int deleteIfVolatile(redisDb *db, robj *key) {
3570     dictEntry *de;
3571
3572     /* No expire? return ASAP */
3573     if (dictSize(db->expires) == 0 ||
3574        (de = dictFind(db->expires,key)) == NULL) return 0;
3575
3576     /* Delete the key */
3577     server.dirty++;
3578     dictDelete(db->expires,key);
3579     return dictDelete(db->dict,key) == DICT_OK;
3580 }
3581
3582 static void expireCommand(redisClient *c) {
3583     dictEntry *de;
3584     int seconds = atoi(c->argv[2]->ptr);
3585
3586     de = dictFind(c->db->dict,c->argv[1]);
3587     if (de == NULL) {
3588         addReply(c,shared.czero);
3589         return;
3590     }
3591     if (seconds <= 0) {
3592         addReply(c, shared.czero);
3593         return;
3594     } else {
3595         time_t when = time(NULL)+seconds;
3596         if (setExpire(c->db,c->argv[1],when))
3597             addReply(c,shared.cone);
3598         else
3599             addReply(c,shared.czero);
3600         return;
3601     }
3602 }
3603
3604 /* =============================== Replication  ============================= */
3605
3606 static int syncWrite(int fd, char *ptr, ssize_t size, int timeout) {
3607     ssize_t nwritten, ret = size;
3608     time_t start = time(NULL);
3609
3610     timeout++;
3611     while(size) {
3612         if (aeWait(fd,AE_WRITABLE,1000) & AE_WRITABLE) {
3613             nwritten = write(fd,ptr,size);
3614             if (nwritten == -1) return -1;
3615             ptr += nwritten;
3616             size -= nwritten;
3617         }
3618         if ((time(NULL)-start) > timeout) {
3619             errno = ETIMEDOUT;
3620             return -1;
3621         }
3622     }
3623     return ret;
3624 }
3625
3626 static int syncRead(int fd, char *ptr, ssize_t size, int timeout) {
3627     ssize_t nread, totread = 0;
3628     time_t start = time(NULL);
3629
3630     timeout++;
3631     while(size) {
3632         if (aeWait(fd,AE_READABLE,1000) & AE_READABLE) {
3633             nread = read(fd,ptr,size);
3634             if (nread == -1) return -1;
3635             ptr += nread;
3636             size -= nread;
3637             totread += nread;
3638         }
3639         if ((time(NULL)-start) > timeout) {
3640             errno = ETIMEDOUT;
3641             return -1;
3642         }
3643     }
3644     return totread;
3645 }
3646
3647 static int syncReadLine(int fd, char *ptr, ssize_t size, int timeout) {
3648     ssize_t nread = 0;
3649
3650     size--;
3651     while(size) {
3652         char c;
3653
3654         if (syncRead(fd,&c,1,timeout) == -1) return -1;
3655         if (c == '\n') {
3656             *ptr = '\0';
3657             if (nread && *(ptr-1) == '\r') *(ptr-1) = '\0';
3658             return nread;
3659         } else {
3660             *ptr++ = c;
3661             *ptr = '\0';
3662             nread++;
3663         }
3664     }
3665     return nread;
3666 }
3667
3668 static void syncCommand(redisClient *c) {
3669     /* ignore SYNC if aleady slave or in monitor mode */
3670     if (c->flags & REDIS_SLAVE) return;
3671
3672     /* SYNC can't be issued when the server has pending data to send to
3673      * the client about already issued commands. We need a fresh reply
3674      * buffer registering the differences between the BGSAVE and the current
3675      * dataset, so that we can copy to other slaves if needed. */
3676     if (listLength(c->reply) != 0) {
3677         addReplySds(c,sdsnew("-ERR SYNC is invalid with pending input\r\n"));
3678         return;
3679     }
3680
3681     redisLog(REDIS_NOTICE,"Slave ask for synchronization");
3682     /* Here we need to check if there is a background saving operation
3683      * in progress, or if it is required to start one */
3684     if (server.bgsaveinprogress) {
3685         /* Ok a background save is in progress. Let's check if it is a good
3686          * one for replication, i.e. if there is another slave that is
3687          * registering differences since the server forked to save */
3688         redisClient *slave;
3689         listNode *ln;
3690
3691         listRewind(server.slaves);
3692         while((ln = listYield(server.slaves))) {
3693             slave = ln->value;
3694             if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_END) break;
3695         }
3696         if (ln) {
3697             /* Perfect, the server is already registering differences for
3698              * another slave. Set the right state, and copy the buffer. */
3699             listRelease(c->reply);
3700             c->reply = listDup(slave->reply);
3701             if (!c->reply) oom("listDup copying slave reply list");
3702             c->replstate = REDIS_REPL_WAIT_BGSAVE_END;
3703             redisLog(REDIS_NOTICE,"Waiting for end of BGSAVE for SYNC");
3704         } else {
3705             /* No way, we need to wait for the next BGSAVE in order to
3706              * register differences */
3707             c->replstate = REDIS_REPL_WAIT_BGSAVE_START;
3708             redisLog(REDIS_NOTICE,"Waiting for next BGSAVE for SYNC");
3709         }
3710     } else {
3711         /* Ok we don't have a BGSAVE in progress, let's start one */
3712         redisLog(REDIS_NOTICE,"Starting BGSAVE for SYNC");
3713         if (rdbSaveBackground(server.dbfilename) != REDIS_OK) {
3714             redisLog(REDIS_NOTICE,"Replication failed, can't BGSAVE");
3715             addReplySds(c,sdsnew("-ERR Unalbe to perform background save\r\n"));
3716             return;
3717         }
3718         c->replstate = REDIS_REPL_WAIT_BGSAVE_END;
3719     }
3720     c->repldbfd = -1;
3721     c->flags |= REDIS_SLAVE;
3722     c->slaveseldb = 0;
3723     if (!listAddNodeTail(server.slaves,c)) oom("listAddNodeTail");
3724     return;
3725 }
3726
3727 static void sendBulkToSlave(aeEventLoop *el, int fd, void *privdata, int mask) {
3728     redisClient *slave = privdata;
3729     REDIS_NOTUSED(el);
3730     REDIS_NOTUSED(mask);
3731     char buf[REDIS_IOBUF_LEN];
3732     ssize_t nwritten, buflen;
3733
3734     if (slave->repldboff == 0) {
3735         /* Write the bulk write count before to transfer the DB. In theory here
3736          * we don't know how much room there is in the output buffer of the
3737          * socket, but in pratice SO_SNDLOWAT (the minimum count for output
3738          * operations) will never be smaller than the few bytes we need. */
3739         sds bulkcount;
3740
3741         bulkcount = sdscatprintf(sdsempty(),"$%lld\r\n",(unsigned long long)
3742             slave->repldbsize);
3743         if (write(fd,bulkcount,sdslen(bulkcount)) != (signed)sdslen(bulkcount))
3744         {
3745             sdsfree(bulkcount);
3746             freeClient(slave);
3747             return;
3748         }
3749         sdsfree(bulkcount);
3750     }
3751     lseek(slave->repldbfd,slave->repldboff,SEEK_SET);
3752     buflen = read(slave->repldbfd,buf,REDIS_IOBUF_LEN);
3753     if (buflen <= 0) {
3754         redisLog(REDIS_WARNING,"Read error sending DB to slave: %s",
3755             (buflen == 0) ? "premature EOF" : strerror(errno));
3756         freeClient(slave);
3757         return;
3758     }
3759     if ((nwritten = write(fd,buf,buflen)) == -1) {
3760         redisLog(REDIS_DEBUG,"Write error sending DB to slave: %s",
3761             strerror(errno));
3762         freeClient(slave);
3763         return;
3764     }
3765     slave->repldboff += nwritten;
3766     if (slave->repldboff == slave->repldbsize) {
3767         close(slave->repldbfd);
3768         slave->repldbfd = -1;
3769         aeDeleteFileEvent(server.el,slave->fd,AE_WRITABLE);
3770         slave->replstate = REDIS_REPL_ONLINE;
3771         if (aeCreateFileEvent(server.el, slave->fd, AE_WRITABLE,
3772             sendReplyToClient, slave, NULL) == AE_ERR) {
3773             freeClient(slave);
3774             return;
3775         }
3776         addReplySds(slave,sdsempty());
3777         redisLog(REDIS_NOTICE,"Synchronization with slave succeeded");
3778     }
3779 }
3780
3781 static void updateSalvesWaitingBgsave(int bgsaveerr) {
3782     listNode *ln;
3783     int startbgsave = 0;
3784
3785     listRewind(server.slaves);
3786     while((ln = listYield(server.slaves))) {
3787         redisClient *slave = ln->value;
3788
3789         if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_START) {
3790             startbgsave = 1;
3791             slave->replstate = REDIS_REPL_WAIT_BGSAVE_END;
3792         } else if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_END) {
3793             struct stat buf;
3794
3795             if (bgsaveerr != REDIS_OK) {
3796                 freeClient(slave);
3797                 redisLog(REDIS_WARNING,"SYNC failed. BGSAVE child returned an error");
3798                 continue;
3799             }
3800             if ((slave->repldbfd = open(server.dbfilename,O_RDONLY)) == -1 ||
3801                 fstat(slave->repldbfd,&buf) == -1) {
3802                 freeClient(slave);
3803                 redisLog(REDIS_WARNING,"SYNC failed. Can't open/stat DB after BGSAVE: %s", strerror(errno));
3804                 continue;
3805             }
3806             slave->repldboff = 0;
3807             slave->repldbsize = buf.st_size;
3808             slave->replstate = REDIS_REPL_SEND_BULK;
3809             aeDeleteFileEvent(server.el,slave->fd,AE_WRITABLE);
3810             if (aeCreateFileEvent(server.el, slave->fd, AE_WRITABLE, sendBulkToSlave, slave, NULL) == AE_ERR) {
3811                 freeClient(slave);
3812                 continue;
3813             }
3814         }
3815     }
3816     if (startbgsave) {
3817         if (rdbSaveBackground(server.dbfilename) != REDIS_OK) {
3818             listRewind(server.slaves);
3819             redisLog(REDIS_WARNING,"SYNC failed. BGSAVE failed");
3820             while((ln = listYield(server.slaves))) {
3821                 redisClient *slave = ln->value;
3822
3823                 if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_START)
3824                     freeClient(slave);
3825             }
3826         }
3827     }
3828 }
3829
3830 static int syncWithMaster(void) {
3831     char buf[1024], tmpfile[256];
3832     int dumpsize;
3833     int fd = anetTcpConnect(NULL,server.masterhost,server.masterport);
3834     int dfd;
3835
3836     if (fd == -1) {
3837         redisLog(REDIS_WARNING,"Unable to connect to MASTER: %s",
3838             strerror(errno));
3839         return REDIS_ERR;
3840     }
3841     /* Issue the SYNC command */
3842     if (syncWrite(fd,"SYNC \r\n",7,5) == -1) {
3843         close(fd);
3844         redisLog(REDIS_WARNING,"I/O error writing to MASTER: %s",
3845             strerror(errno));
3846         return REDIS_ERR;
3847     }
3848     /* Read the bulk write count */
3849     if (syncReadLine(fd,buf,1024,5) == -1) {
3850         close(fd);
3851         redisLog(REDIS_WARNING,"I/O error reading bulk count from MASTER: %s",
3852             strerror(errno));
3853         return REDIS_ERR;
3854     }
3855     dumpsize = atoi(buf+1);
3856     redisLog(REDIS_NOTICE,"Receiving %d bytes data dump from MASTER",dumpsize);
3857     /* Read the bulk write data on a temp file */
3858     snprintf(tmpfile,256,"temp-%d.%ld.rdb",(int)time(NULL),(long int)random());
3859     dfd = open(tmpfile,O_CREAT|O_WRONLY,0644);
3860     if (dfd == -1) {
3861         close(fd);
3862         redisLog(REDIS_WARNING,"Opening the temp file needed for MASTER <-> SLAVE synchronization: %s",strerror(errno));
3863         return REDIS_ERR;
3864     }
3865     while(dumpsize) {
3866         int nread, nwritten;
3867
3868         nread = read(fd,buf,(dumpsize < 1024)?dumpsize:1024);
3869         if (nread == -1) {
3870             redisLog(REDIS_WARNING,"I/O error trying to sync with MASTER: %s",
3871                 strerror(errno));
3872             close(fd);
3873             close(dfd);
3874             return REDIS_ERR;
3875         }
3876         nwritten = write(dfd,buf,nread);
3877         if (nwritten == -1) {
3878             redisLog(REDIS_WARNING,"Write error writing to the DB dump file needed for MASTER <-> SLAVE synchrnonization: %s", strerror(errno));
3879             close(fd);
3880             close(dfd);
3881             return REDIS_ERR;
3882         }
3883         dumpsize -= nread;
3884     }
3885     close(dfd);
3886     if (rename(tmpfile,server.dbfilename) == -1) {
3887         redisLog(REDIS_WARNING,"Failed trying to rename the temp DB into dump.rdb in MASTER <-> SLAVE synchronization: %s", strerror(errno));
3888         unlink(tmpfile);
3889         close(fd);
3890         return REDIS_ERR;
3891     }
3892     emptyDb();
3893     if (rdbLoad(server.dbfilename) != REDIS_OK) {
3894         redisLog(REDIS_WARNING,"Failed trying to load the MASTER synchronization DB from disk");
3895         close(fd);
3896         return REDIS_ERR;
3897     }
3898     server.master = createClient(fd);
3899     server.master->flags |= REDIS_MASTER;
3900     server.replstate = REDIS_REPL_CONNECTED;
3901     return REDIS_OK;
3902 }
3903
3904 /* =================================== Main! ================================ */
3905
3906 #ifdef __linux__
3907 int linuxOvercommitMemoryValue(void) {
3908     FILE *fp = fopen("/proc/sys/vm/overcommit_memory","r");
3909     char buf[64];
3910
3911     if (!fp) return -1;
3912     if (fgets(buf,64,fp) == NULL) {
3913         fclose(fp);
3914         return -1;
3915     }
3916     fclose(fp);
3917
3918     return atoi(buf);
3919 }
3920
3921 void linuxOvercommitMemoryWarning(void) {
3922     if (linuxOvercommitMemoryValue() == 0) {
3923         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.");
3924     }
3925 }
3926 #endif /* __linux__ */
3927
3928 static void daemonize(void) {
3929     int fd;
3930     FILE *fp;
3931
3932     if (fork() != 0) exit(0); /* parent exits */
3933     setsid(); /* create a new session */
3934
3935     /* Every output goes to /dev/null. If Redis is daemonized but
3936      * the 'logfile' is set to 'stdout' in the configuration file
3937      * it will not log at all. */
3938     if ((fd = open("/dev/null", O_RDWR, 0)) != -1) {
3939         dup2(fd, STDIN_FILENO);
3940         dup2(fd, STDOUT_FILENO);
3941         dup2(fd, STDERR_FILENO);
3942         if (fd > STDERR_FILENO) close(fd);
3943     }
3944     /* Try to write the pid file */
3945     fp = fopen(server.pidfile,"w");
3946     if (fp) {
3947         fprintf(fp,"%d\n",getpid());
3948         fclose(fp);
3949     }
3950 }
3951
3952 int main(int argc, char **argv) {
3953 #ifdef __linux__
3954     linuxOvercommitMemoryWarning();
3955 #endif
3956
3957     initServerConfig();
3958     if (argc == 2) {
3959         ResetServerSaveParams();
3960         loadServerConfig(argv[1]);
3961     } else if (argc > 2) {
3962         fprintf(stderr,"Usage: ./redis-server [/path/to/redis.conf]\n");
3963         exit(1);
3964     }
3965     initServer();
3966     if (server.daemonize) daemonize();
3967     redisLog(REDIS_NOTICE,"Server started, Redis version " REDIS_VERSION);
3968     if (rdbLoad(server.dbfilename) == REDIS_OK)
3969         redisLog(REDIS_NOTICE,"DB loaded from disk");
3970     if (aeCreateFileEvent(server.el, server.fd, AE_READABLE,
3971         acceptHandler, NULL, NULL) == AE_ERR) oom("creating file event");
3972     redisLog(REDIS_NOTICE,"The server is now ready to accept connections on port %d", server.port);
3973     aeMain(server.el);
3974     aeDeleteEventLoop(server.el);
3975     return 0;
3976 }