src/redis.c

   1 /*
   2  * Copyright (c) 2009-2010, 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 #include "redis.h"
  31
  32 #ifdef HAVE_BACKTRACE
  33 #include <execinfo.h>
  34 #include <ucontext.h>
  35 #endif /* HAVE_BACKTRACE */
  36
  37 #include <time.h>
  38 #include <signal.h>
  39 #include <sys/wait.h>
  40 #include <errno.h>
  41 #include <assert.h>
  42 #include <ctype.h>
  43 #include <stdarg.h>
  44 #include <arpa/inet.h>
  45 #include <sys/stat.h>
  46 #include <fcntl.h>
  47 #include <sys/time.h>
  48 #include <sys/resource.h>
  49 #include <sys/uio.h>
  50 #include <limits.h>
  51 #include <float.h>
  52 #include <math.h>
  53 #include <pthread.h>
  54 #include <sys/resource.h>
  55
  56 /* Our shared "common" objects */
  57
  58 struct sharedObjectsStruct shared;
  59
  60 /* Global vars that are actally used as constants. The following double
  61  * values are used for double on-disk serialization, and are initialized
  62  * at runtime to avoid strange compiler optimizations. */
  63
  64 double R_Zero, R_PosInf, R_NegInf, R_Nan;
  65
  66 /*================================= Globals ================================= */
  67
  68 /* Global vars */
  69 struct redisServer server; /* server global state */
  70 struct redisCommand *commandTable;
  71 struct redisCommand readonlyCommandTable[] = {
  72     {"get",getCommand,2,0,NULL,1,1,1},
  73     {"set",setCommand,3,REDIS_CMD_DENYOOM,NULL,0,0,0},
  74     {"setnx",setnxCommand,3,REDIS_CMD_DENYOOM,NULL,0,0,0},
  75     {"setex",setexCommand,4,REDIS_CMD_DENYOOM,NULL,0,0,0},
  76     {"append",appendCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
  77     {"strlen",strlenCommand,2,0,NULL,1,1,1},
  78     {"del",delCommand,-2,0,NULL,0,0,0},
  79     {"exists",existsCommand,2,0,NULL,1,1,1},
  80     {"setbit",setbitCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
  81     {"getbit",getbitCommand,3,0,NULL,1,1,1},
  82     {"setrange",setrangeCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
  83     {"getrange",getrangeCommand,4,0,NULL,1,1,1},
  84     {"substr",getrangeCommand,4,0,NULL,1,1,1},
  85     {"incr",incrCommand,2,REDIS_CMD_DENYOOM,NULL,1,1,1},
  86     {"decr",decrCommand,2,REDIS_CMD_DENYOOM,NULL,1,1,1},
  87     {"mget",mgetCommand,-2,0,NULL,1,-1,1},
  88     {"rpush",rpushCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
  89     {"lpush",lpushCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
  90     {"rpushx",rpushxCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
  91     {"lpushx",lpushxCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
  92     {"linsert",linsertCommand,5,REDIS_CMD_DENYOOM,NULL,1,1,1},
  93     {"rpop",rpopCommand,2,0,NULL,1,1,1},
  94     {"lpop",lpopCommand,2,0,NULL,1,1,1},
  95     {"brpop",brpopCommand,-3,0,NULL,1,1,1},
  96     {"brpoplpush",brpoplpushCommand,4,REDIS_CMD_DENYOOM,NULL,1,2,1},
  97     {"blpop",blpopCommand,-3,0,NULL,1,1,1},
  98     {"llen",llenCommand,2,0,NULL,1,1,1},
  99     {"lindex",lindexCommand,3,0,NULL,1,1,1},
 100     {"lset",lsetCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
 101     {"lrange",lrangeCommand,4,0,NULL,1,1,1},
 102     {"ltrim",ltrimCommand,4,0,NULL,1,1,1},
 103     {"lrem",lremCommand,4,0,NULL,1,1,1},
 104     {"rpoplpush",rpoplpushCommand,3,REDIS_CMD_DENYOOM,NULL,1,2,1},
 105     {"sadd",saddCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
 106     {"srem",sremCommand,3,0,NULL,1,1,1},
 107     {"smove",smoveCommand,4,0,NULL,1,2,1},
 108     {"sismember",sismemberCommand,3,0,NULL,1,1,1},
 109     {"scard",scardCommand,2,0,NULL,1,1,1},
 110     {"spop",spopCommand,2,0,NULL,1,1,1},
 111     {"srandmember",srandmemberCommand,2,0,NULL,1,1,1},
 112     {"sinter",sinterCommand,-2,REDIS_CMD_DENYOOM,NULL,1,-1,1},
 113     {"sinterstore",sinterstoreCommand,-3,REDIS_CMD_DENYOOM,NULL,2,-1,1},
 114     {"sunion",sunionCommand,-2,REDIS_CMD_DENYOOM,NULL,1,-1,1},
 115     {"sunionstore",sunionstoreCommand,-3,REDIS_CMD_DENYOOM,NULL,2,-1,1},
 116     {"sdiff",sdiffCommand,-2,REDIS_CMD_DENYOOM,NULL,1,-1,1},
 117     {"sdiffstore",sdiffstoreCommand,-3,REDIS_CMD_DENYOOM,NULL,2,-1,1},
 118     {"smembers",sinterCommand,2,0,NULL,1,1,1},
 119     {"zadd",zaddCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
 120     {"zincrby",zincrbyCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
 121     {"zrem",zremCommand,3,0,NULL,1,1,1},
 122     {"zremrangebyscore",zremrangebyscoreCommand,4,0,NULL,1,1,1},
 123     {"zremrangebyrank",zremrangebyrankCommand,4,0,NULL,1,1,1},
 124     {"zunionstore",zunionstoreCommand,-4,REDIS_CMD_DENYOOM,zunionInterBlockClientOnSwappedKeys,0,0,0},
 125     {"zinterstore",zinterstoreCommand,-4,REDIS_CMD_DENYOOM,zunionInterBlockClientOnSwappedKeys,0,0,0},
 126     {"zrange",zrangeCommand,-4,0,NULL,1,1,1},
 127     {"zrangebyscore",zrangebyscoreCommand,-4,0,NULL,1,1,1},
 128     {"zrevrangebyscore",zrevrangebyscoreCommand,-4,0,NULL,1,1,1},
 129     {"zcount",zcountCommand,4,0,NULL,1,1,1},
 130     {"zrevrange",zrevrangeCommand,-4,0,NULL,1,1,1},
 131     {"zcard",zcardCommand,2,0,NULL,1,1,1},
 132     {"zscore",zscoreCommand,3,0,NULL,1,1,1},
 133     {"zrank",zrankCommand,3,0,NULL,1,1,1},
 134     {"zrevrank",zrevrankCommand,3,0,NULL,1,1,1},
 135     {"hset",hsetCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
 136     {"hsetnx",hsetnxCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
 137     {"hget",hgetCommand,3,0,NULL,1,1,1},
 138     {"hmset",hmsetCommand,-4,REDIS_CMD_DENYOOM,NULL,1,1,1},
 139     {"hmget",hmgetCommand,-3,0,NULL,1,1,1},
 140     {"hincrby",hincrbyCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
 141     {"hdel",hdelCommand,3,0,NULL,1,1,1},
 142     {"hlen",hlenCommand,2,0,NULL,1,1,1},
 143     {"hkeys",hkeysCommand,2,0,NULL,1,1,1},
 144     {"hvals",hvalsCommand,2,0,NULL,1,1,1},
 145     {"hgetall",hgetallCommand,2,0,NULL,1,1,1},
 146     {"hexists",hexistsCommand,3,0,NULL,1,1,1},
 147     {"incrby",incrbyCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
 148     {"decrby",decrbyCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
 149     {"getset",getsetCommand,3,REDIS_CMD_DENYOOM,NULL,1,1,1},
 150     {"mset",msetCommand,-3,REDIS_CMD_DENYOOM,NULL,1,-1,2},
 151     {"msetnx",msetnxCommand,-3,REDIS_CMD_DENYOOM,NULL,1,-1,2},
 152     {"randomkey",randomkeyCommand,1,0,NULL,0,0,0},
 153     {"select",selectCommand,2,0,NULL,0,0,0},
 154     {"move",moveCommand,3,0,NULL,1,1,1},
 155     {"rename",renameCommand,3,0,NULL,1,1,1},
 156     {"renamenx",renamenxCommand,3,0,NULL,1,1,1},
 157     {"expire",expireCommand,3,0,NULL,0,0,0},
 158     {"expireat",expireatCommand,3,0,NULL,0,0,0},
 159     {"keys",keysCommand,2,0,NULL,0,0,0},
 160     {"dbsize",dbsizeCommand,1,0,NULL,0,0,0},
 161     {"auth",authCommand,2,0,NULL,0,0,0},
 162     {"ping",pingCommand,1,0,NULL,0,0,0},
 163     {"echo",echoCommand,2,0,NULL,0,0,0},
 164     {"save",saveCommand,1,0,NULL,0,0,0},
 165     {"bgsave",bgsaveCommand,1,0,NULL,0,0,0},
 166     {"bgrewriteaof",bgrewriteaofCommand,1,0,NULL,0,0,0},
 167     {"shutdown",shutdownCommand,1,0,NULL,0,0,0},
 168     {"lastsave",lastsaveCommand,1,0,NULL,0,0,0},
 169     {"type",typeCommand,2,0,NULL,1,1,1},
 170     {"multi",multiCommand,1,0,NULL,0,0,0},
 171     {"exec",execCommand,1,REDIS_CMD_DENYOOM,execBlockClientOnSwappedKeys,0,0,0},
 172     {"discard",discardCommand,1,0,NULL,0,0,0},
 173     {"sync",syncCommand,1,0,NULL,0,0,0},
 174     {"flushdb",flushdbCommand,1,0,NULL,0,0,0},
 175     {"flushall",flushallCommand,1,0,NULL,0,0,0},
 176     {"sort",sortCommand,-2,REDIS_CMD_DENYOOM,NULL,1,1,1},
 177     {"info",infoCommand,1,0,NULL,0,0,0},
 178     {"monitor",monitorCommand,1,0,NULL,0,0,0},
 179     {"ttl",ttlCommand,2,0,NULL,1,1,1},
 180     {"persist",persistCommand,2,0,NULL,1,1,1},
 181     {"slaveof",slaveofCommand,3,0,NULL,0,0,0},
 182     {"debug",debugCommand,-2,0,NULL,0,0,0},
 183     {"config",configCommand,-2,0,NULL,0,0,0},
 184     {"subscribe",subscribeCommand,-2,0,NULL,0,0,0},
 185     {"unsubscribe",unsubscribeCommand,-1,0,NULL,0,0,0},
 186     {"psubscribe",psubscribeCommand,-2,0,NULL,0,0,0},
 187     {"punsubscribe",punsubscribeCommand,-1,0,NULL,0,0,0},
 188     {"publish",publishCommand,3,REDIS_CMD_FORCE_REPLICATION,NULL,0,0,0},
 189     {"watch",watchCommand,-2,0,NULL,0,0,0},
 190     {"unwatch",unwatchCommand,1,0,NULL,0,0,0}
 191 };
 192
 193 /*============================ Utility functions ============================ */
 194
 195 void redisLog(int level, const char *fmt, ...) {
 196     const int syslogLevelMap[] = { LOG_DEBUG, LOG_INFO, LOG_NOTICE, LOG_WARNING };
 197     const char *c = ".-*#";
 198     time_t now = time(NULL);
 199     va_list ap;
 200     FILE *fp;
 201     char buf[64];
 202     char msg[REDIS_MAX_LOGMSG_LEN];
 203
 204     if (level < server.verbosity) return;
 205
 206     fp = (server.logfile == NULL) ? stdout : fopen(server.logfile,"a");
 207     if (!fp) return;
 208
 209     va_start(ap, fmt);
 210     vsnprintf(msg, sizeof(msg), fmt, ap);
 211     va_end(ap);
 212
 213     strftime(buf,sizeof(buf),"%d %b %H:%M:%S",localtime(&now));
 214     fprintf(fp,"[%d] %s %c %s\n",(int)getpid(),buf,c[level],msg);
 215     fflush(fp);
 216
 217     if (server.logfile) fclose(fp);
 218
 219     if (server.syslog_enabled) syslog(syslogLevelMap[level], "%s", msg);
 220 }
 221
 222 /* Redis generally does not try to recover from out of memory conditions
 223  * when allocating objects or strings, it is not clear if it will be possible
 224  * to report this condition to the client since the networking layer itself
 225  * is based on heap allocation for send buffers, so we simply abort.
 226  * At least the code will be simpler to read... */
 227 void oom(const char *msg) {
 228     redisLog(REDIS_WARNING, "%s: Out of memory\n",msg);
 229     sleep(1);
 230     abort();
 231 }
 232
 233 /*====================== Hash table type implementation  ==================== */
 234
 235 /* This is an hash table type that uses the SDS dynamic strings libary as
 236  * keys and radis objects as values (objects can hold SDS strings,
 237  * lists, sets). */
 238
 239 void dictVanillaFree(void *privdata, void *val)
 240 {
 241     DICT_NOTUSED(privdata);
 242     zfree(val);
 243 }
 244
 245 void dictListDestructor(void *privdata, void *val)
 246 {
 247     DICT_NOTUSED(privdata);
 248     listRelease((list*)val);
 249 }
 250
 251 int dictSdsKeyCompare(void *privdata, const void *key1,
 252         const void *key2)
 253 {
 254     int l1,l2;
 255     DICT_NOTUSED(privdata);
 256
 257     l1 = sdslen((sds)key1);
 258     l2 = sdslen((sds)key2);
 259     if (l1 != l2) return 0;
 260     return memcmp(key1, key2, l1) == 0;
 261 }
 262
 263 /* A case insensitive version used for the command lookup table. */
 264 int dictSdsKeyCaseCompare(void *privdata, const void *key1,
 265         const void *key2)
 266 {
 267     DICT_NOTUSED(privdata);
 268
 269     return strcasecmp(key1, key2) == 0;
 270 }
 271
 272 void dictRedisObjectDestructor(void *privdata, void *val)
 273 {
 274     DICT_NOTUSED(privdata);
 275
 276     if (val == NULL) return; /* Values of swapped out keys as set to NULL */
 277     decrRefCount(val);
 278 }
 279
 280 void dictSdsDestructor(void *privdata, void *val)
 281 {
 282     DICT_NOTUSED(privdata);
 283
 284     sdsfree(val);
 285 }
 286
 287 int dictObjKeyCompare(void *privdata, const void *key1,
 288         const void *key2)
 289 {
 290     const robj *o1 = key1, *o2 = key2;
 291     return dictSdsKeyCompare(privdata,o1->ptr,o2->ptr);
 292 }
 293
 294 unsigned int dictObjHash(const void *key) {
 295     const robj *o = key;
 296     return dictGenHashFunction(o->ptr, sdslen((sds)o->ptr));
 297 }
 298
 299 unsigned int dictSdsHash(const void *key) {
 300     return dictGenHashFunction((unsigned char*)key, sdslen((char*)key));
 301 }
 302
 303 unsigned int dictSdsCaseHash(const void *key) {
 304     return dictGenCaseHashFunction((unsigned char*)key, sdslen((char*)key));
 305 }
 306
 307 int dictEncObjKeyCompare(void *privdata, const void *key1,
 308         const void *key2)
 309 {
 310     robj *o1 = (robj*) key1, *o2 = (robj*) key2;
 311     int cmp;
 312
 313     if (o1->encoding == REDIS_ENCODING_INT &&
 314         o2->encoding == REDIS_ENCODING_INT)
 315             return o1->ptr == o2->ptr;
 316
 317     o1 = getDecodedObject(o1);
 318     o2 = getDecodedObject(o2);
 319     cmp = dictSdsKeyCompare(privdata,o1->ptr,o2->ptr);
 320     decrRefCount(o1);
 321     decrRefCount(o2);
 322     return cmp;
 323 }
 324
 325 unsigned int dictEncObjHash(const void *key) {
 326     robj *o = (robj*) key;
 327
 328     if (o->encoding == REDIS_ENCODING_RAW) {
 329         return dictGenHashFunction(o->ptr, sdslen((sds)o->ptr));
 330     } else {
 331         if (o->encoding == REDIS_ENCODING_INT) {
 332             char buf[32];
 333             int len;
 334
 335             len = ll2string(buf,32,(long)o->ptr);
 336             return dictGenHashFunction((unsigned char*)buf, len);
 337         } else {
 338             unsigned int hash;
 339
 340             o = getDecodedObject(o);
 341             hash = dictGenHashFunction(o->ptr, sdslen((sds)o->ptr));
 342             decrRefCount(o);
 343             return hash;
 344         }
 345     }
 346 }
 347
 348 /* Sets type */
 349 dictType setDictType = {
 350     dictEncObjHash,            /* hash function */
 351     NULL,                      /* key dup */
 352     NULL,                      /* val dup */
 353     dictEncObjKeyCompare,      /* key compare */
 354     dictRedisObjectDestructor, /* key destructor */
 355     NULL                       /* val destructor */
 356 };
 357
 358 /* Sorted sets hash (note: a skiplist is used in addition to the hash table) */
 359 dictType zsetDictType = {
 360     dictEncObjHash,            /* hash function */
 361     NULL,                      /* key dup */
 362     NULL,                      /* val dup */
 363     dictEncObjKeyCompare,      /* key compare */
 364     dictRedisObjectDestructor, /* key destructor */
 365     NULL                       /* val destructor */
 366 };
 367
 368 /* Db->dict, keys are sds strings, vals are Redis objects. */
 369 dictType dbDictType = {
 370     dictSdsHash,                /* hash function */
 371     NULL,                       /* key dup */
 372     NULL,                       /* val dup */
 373     dictSdsKeyCompare,          /* key compare */
 374     dictSdsDestructor,          /* key destructor */
 375     dictRedisObjectDestructor   /* val destructor */
 376 };
 377
 378 /* Db->expires */
 379 dictType keyptrDictType = {
 380     dictSdsHash,               /* hash function */
 381     NULL,                      /* key dup */
 382     NULL,                      /* val dup */
 383     dictSdsKeyCompare,         /* key compare */
 384     NULL,                      /* key destructor */
 385     NULL                       /* val destructor */
 386 };
 387
 388 /* Command table. sds string -> command struct pointer. */
 389 dictType commandTableDictType = {
 390     dictSdsCaseHash,           /* hash function */
 391     NULL,                      /* key dup */
 392     NULL,                      /* val dup */
 393     dictSdsKeyCaseCompare,     /* key compare */
 394     dictSdsDestructor,         /* key destructor */
 395     NULL                       /* val destructor */
 396 };
 397
 398 /* Hash type hash table (note that small hashes are represented with zimpaps) */
 399 dictType hashDictType = {
 400     dictEncObjHash,             /* hash function */
 401     NULL,                       /* key dup */
 402     NULL,                       /* val dup */
 403     dictEncObjKeyCompare,       /* key compare */
 404     dictRedisObjectDestructor,  /* key destructor */
 405     dictRedisObjectDestructor   /* val destructor */
 406 };
 407
 408 /* Keylist hash table type has unencoded redis objects as keys and
 409  * lists as values. It's used for blocking operations (BLPOP) and to
 410  * map swapped keys to a list of clients waiting for this keys to be loaded. */
 411 dictType keylistDictType = {
 412     dictObjHash,                /* hash function */
 413     NULL,                       /* key dup */
 414     NULL,                       /* val dup */
 415     dictObjKeyCompare,          /* key compare */
 416     dictRedisObjectDestructor,  /* key destructor */
 417     dictListDestructor          /* val destructor */
 418 };
 419
 420 int htNeedsResize(dict *dict) {
 421     long long size, used;
 422
 423     size = dictSlots(dict);
 424     used = dictSize(dict);
 425     return (size && used && size > DICT_HT_INITIAL_SIZE &&
 426             (used*100/size < REDIS_HT_MINFILL));
 427 }
 428
 429 /* If the percentage of used slots in the HT reaches REDIS_HT_MINFILL
 430  * we resize the hash table to save memory */
 431 void tryResizeHashTables(void) {
 432     int j;
 433
 434     for (j = 0; j < server.dbnum; j++) {
 435         if (htNeedsResize(server.db[j].dict))
 436             dictResize(server.db[j].dict);
 437         if (htNeedsResize(server.db[j].expires))
 438             dictResize(server.db[j].expires);
 439     }
 440 }
 441
 442 /* Our hash table implementation performs rehashing incrementally while
 443  * we write/read from the hash table. Still if the server is idle, the hash
 444  * table will use two tables for a long time. So we try to use 1 millisecond
 445  * of CPU time at every serverCron() loop in order to rehash some key. */
 446 void incrementallyRehash(void) {
 447     int j;
 448
 449     for (j = 0; j < server.dbnum; j++) {
 450         if (dictIsRehashing(server.db[j].dict)) {
 451             dictRehashMilliseconds(server.db[j].dict,1);
 452             break; /* already used our millisecond for this loop... */
 453         }
 454     }
 455 }
 456
 457 /* This function is called once a background process of some kind terminates,
 458  * as we want to avoid resizing the hash tables when there is a child in order
 459  * to play well with copy-on-write (otherwise when a resize happens lots of
 460  * memory pages are copied). The goal of this function is to update the ability
 461  * for dict.c to resize the hash tables accordingly to the fact we have o not
 462  * running childs. */
 463 void updateDictResizePolicy(void) {
 464     if (server.bgsavechildpid == -1 && server.bgrewritechildpid == -1)
 465         dictEnableResize();
 466     else
 467         dictDisableResize();
 468 }
 469
 470 /* ======================= Cron: called every 100 ms ======================== */
 471
 472 /* Try to expire a few timed out keys. The algorithm used is adaptive and
 473  * will use few CPU cycles if there are few expiring keys, otherwise
 474  * it will get more aggressive to avoid that too much memory is used by
 475  * keys that can be removed from the keyspace. */
 476 void activeExpireCycle(void) {
 477     int j;
 478
 479     for (j = 0; j < server.dbnum; j++) {
 480         int expired;
 481         redisDb *db = server.db+j;
 482
 483         /* Continue to expire if at the end of the cycle more than 25%
 484          * of the keys were expired. */
 485         do {
 486             long num = dictSize(db->expires);
 487             time_t now = time(NULL);
 488
 489             expired = 0;
 490             if (num > REDIS_EXPIRELOOKUPS_PER_CRON)
 491                 num = REDIS_EXPIRELOOKUPS_PER_CRON;
 492             while (num--) {
 493                 dictEntry *de;
 494                 time_t t;
 495
 496                 if ((de = dictGetRandomKey(db->expires)) == NULL) break;
 497                 t = (time_t) dictGetEntryVal(de);
 498                 if (now > t) {
 499                     sds key = dictGetEntryKey(de);
 500                     robj *keyobj = createStringObject(key,sdslen(key));
 501
 502                     propagateExpire(db,keyobj);
 503                     dbDelete(db,keyobj);
 504                     decrRefCount(keyobj);
 505                     expired++;
 506                     server.stat_expiredkeys++;
 507                 }
 508             }
 509         } while (expired > REDIS_EXPIRELOOKUPS_PER_CRON/4);
 510     }
 511 }
 512
 513 void updateLRUClock(void) {
 514     server.lruclock = (time(NULL)/REDIS_LRU_CLOCK_RESOLUTION) &
 515                                                 REDIS_LRU_CLOCK_MAX;
 516 }
 517
 518 int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
 519     int j, loops = server.cronloops++;
 520     REDIS_NOTUSED(eventLoop);
 521     REDIS_NOTUSED(id);
 522     REDIS_NOTUSED(clientData);
 523
 524     /* We take a cached value of the unix time in the global state because
 525      * with virtual memory and aging there is to store the current time
 526      * in objects at every object access, and accuracy is not needed.
 527      * To access a global var is faster than calling time(NULL) */
 528     server.unixtime = time(NULL);
 529     /* We have just 22 bits per object for LRU information.
 530      * So we use an (eventually wrapping) LRU clock with 10 seconds resolution.
 531      * 2^22 bits with 10 seconds resoluton is more or less 1.5 years.
 532      *
 533      * Note that even if this will wrap after 1.5 years it's not a problem,
 534      * everything will still work but just some object will appear younger
 535      * to Redis. But for this to happen a given object should never be touched
 536      * for 1.5 years.
 537      *
 538      * Note that you can change the resolution altering the
 539      * REDIS_LRU_CLOCK_RESOLUTION define.
 540      */
 541     updateLRUClock();
 542
 543     /* We received a SIGTERM, shutting down here in a safe way, as it is
 544      * not ok doing so inside the signal handler. */
 545     if (server.shutdown_asap) {
 546         if (prepareForShutdown() == REDIS_OK) exit(0);
 547         redisLog(REDIS_WARNING,"SIGTERM received but errors trying to shut down the server, check the logs for more information");
 548     }
 549
 550     /* Show some info about non-empty databases */
 551     for (j = 0; j < server.dbnum; j++) {
 552         long long size, used, vkeys;
 553
 554         size = dictSlots(server.db[j].dict);
 555         used = dictSize(server.db[j].dict);
 556         vkeys = dictSize(server.db[j].expires);
 557         if (!(loops % 50) && (used || vkeys)) {
 558             redisLog(REDIS_VERBOSE,"DB %d: %lld keys (%lld volatile) in %lld slots HT.",j,used,vkeys,size);
 559             /* dictPrintStats(server.dict); */
 560         }
 561     }
 562
 563     /* We don't want to resize the hash tables while a bacground saving
 564      * is in progress: the saving child is created using fork() that is
 565      * implemented with a copy-on-write semantic in most modern systems, so
 566      * if we resize the HT while there is the saving child at work actually
 567      * a lot of memory movements in the parent will cause a lot of pages
 568      * copied. */
 569     if (server.bgsavechildpid == -1 && server.bgrewritechildpid == -1) {
 570         if (!(loops % 10)) tryResizeHashTables();
 571         if (server.activerehashing) incrementallyRehash();
 572     }
 573
 574     /* Show information about connected clients */
 575     if (!(loops % 50)) {
 576         redisLog(REDIS_VERBOSE,"%d clients connected (%d slaves), %zu bytes in use",
 577             listLength(server.clients)-listLength(server.slaves),
 578             listLength(server.slaves),
 579             zmalloc_used_memory());
 580     }
 581
 582     /* Close connections of timedout clients */
 583     if ((server.maxidletime && !(loops % 100)) || server.bpop_blocked_clients)
 584         closeTimedoutClients();
 585
 586     /* Check if a background saving or AOF rewrite in progress terminated */
 587     if (server.bgsavechildpid != -1 || server.bgrewritechildpid != -1) {
 588         int statloc;
 589         pid_t pid;
 590
 591         if ((pid = wait3(&statloc,WNOHANG,NULL)) != 0) {
 592             if (pid == server.bgsavechildpid) {
 593                 backgroundSaveDoneHandler(statloc);
 594             } else {
 595                 backgroundRewriteDoneHandler(statloc);
 596             }
 597             updateDictResizePolicy();
 598         }
 599     } else {
 600         /* If there is not a background saving in progress check if
 601          * we have to save now */
 602          time_t now = time(NULL);
 603          for (j = 0; j < server.saveparamslen; j++) {
 604             struct saveparam *sp = server.saveparams+j;
 605
 606             if (server.dirty >= sp->changes &&
 607                 now-server.lastsave > sp->seconds) {
 608                 redisLog(REDIS_NOTICE,"%d changes in %d seconds. Saving...",
 609                     sp->changes, sp->seconds);
 610                 rdbSaveBackground(server.dbfilename);
 611                 break;
 612             }
 613          }
 614     }
 615
 616     /* Expire a few keys per cycle, only if this is a master.
 617      * On slaves we wait for DEL operations synthesized by the master
 618      * in order to guarantee a strict consistency. */
 619     if (server.masterhost == NULL) activeExpireCycle();
 620
 621     /* Remove a few cached objects from memory if we are over the
 622      * configured memory limit */
 623     while (server.ds_enabled && zmalloc_used_memory() >
 624             server.cache_max_memory)
 625     {
 626         if (cacheFreeOneEntry() == REDIS_ERR) break;
 627     }
 628
 629     /* Replication cron function -- used to reconnect to master and
 630      * to detect transfer failures. */
 631     if (!(loops % 10)) replicationCron();
 632
 633     return 100;
 634 }
 635
 636 /* This function gets called every time Redis is entering the
 637  * main loop of the event driven library, that is, before to sleep
 638  * for ready file descriptors. */
 639 void beforeSleep(struct aeEventLoop *eventLoop) {
 640     REDIS_NOTUSED(eventLoop);
 641     listNode *ln;
 642     redisClient *c;
 643
 644     /* Awake clients that got all the on disk keys they requested */
 645     if (server.ds_enabled && listLength(server.io_ready_clients)) {
 646         listIter li;
 647
 648         listRewind(server.io_ready_clients,&li);
 649         while((ln = listNext(&li))) {
 650             c = ln->value;
 651             struct redisCommand *cmd;
 652
 653             /* Resume the client. */
 654             listDelNode(server.io_ready_clients,ln);
 655             c->flags &= (~REDIS_IO_WAIT);
 656             server.cache_blocked_clients--;
 657             aeCreateFileEvent(server.el, c->fd, AE_READABLE,
 658                 readQueryFromClient, c);
 659             cmd = lookupCommand(c->argv[0]->ptr);
 660             redisAssert(cmd != NULL);
 661             call(c,cmd);
 662             resetClient(c);
 663             /* There may be more data to process in the input buffer. */
 664             if (c->querybuf && sdslen(c->querybuf) > 0)
 665                 processInputBuffer(c);
 666         }
 667     }
 668
 669     /* Try to process pending commands for clients that were just unblocked. */
 670     while (listLength(server.unblocked_clients)) {
 671         ln = listFirst(server.unblocked_clients);
 672         redisAssert(ln != NULL);
 673         c = ln->value;
 674         listDelNode(server.unblocked_clients,ln);
 675
 676         /* Process remaining data in the input buffer. */
 677         if (c->querybuf && sdslen(c->querybuf) > 0)
 678             processInputBuffer(c);
 679     }
 680
 681     /* Write the AOF buffer on disk */
 682     flushAppendOnlyFile();
 683 }
 684
 685 /* =========================== Server initialization ======================== */
 686
 687 void createSharedObjects(void) {
 688     int j;
 689
 690     shared.crlf = createObject(REDIS_STRING,sdsnew("\r\n"));
 691     shared.ok = createObject(REDIS_STRING,sdsnew("+OK\r\n"));
 692     shared.err = createObject(REDIS_STRING,sdsnew("-ERR\r\n"));
 693     shared.emptybulk = createObject(REDIS_STRING,sdsnew("$0\r\n\r\n"));
 694     shared.czero = createObject(REDIS_STRING,sdsnew(":0\r\n"));
 695     shared.cone = createObject(REDIS_STRING,sdsnew(":1\r\n"));
 696     shared.cnegone = createObject(REDIS_STRING,sdsnew(":-1\r\n"));
 697     shared.nullbulk = createObject(REDIS_STRING,sdsnew("$-1\r\n"));
 698     shared.nullmultibulk = createObject(REDIS_STRING,sdsnew("*-1\r\n"));
 699     shared.emptymultibulk = createObject(REDIS_STRING,sdsnew("*0\r\n"));
 700     shared.pong = createObject(REDIS_STRING,sdsnew("+PONG\r\n"));
 701     shared.queued = createObject(REDIS_STRING,sdsnew("+QUEUED\r\n"));
 702     shared.wrongtypeerr = createObject(REDIS_STRING,sdsnew(
 703         "-ERR Operation against a key holding the wrong kind of value\r\n"));
 704     shared.nokeyerr = createObject(REDIS_STRING,sdsnew(
 705         "-ERR no such key\r\n"));
 706     shared.syntaxerr = createObject(REDIS_STRING,sdsnew(
 707         "-ERR syntax error\r\n"));
 708     shared.sameobjecterr = createObject(REDIS_STRING,sdsnew(
 709         "-ERR source and destination objects are the same\r\n"));
 710     shared.outofrangeerr = createObject(REDIS_STRING,sdsnew(
 711         "-ERR index out of range\r\n"));
 712     shared.loadingerr = createObject(REDIS_STRING,sdsnew(
 713         "-LOADING Redis is loading the dataset in memory\r\n"));
 714     shared.space = createObject(REDIS_STRING,sdsnew(" "));
 715     shared.colon = createObject(REDIS_STRING,sdsnew(":"));
 716     shared.plus = createObject(REDIS_STRING,sdsnew("+"));
 717     shared.select0 = createStringObject("select 0\r\n",10);
 718     shared.select1 = createStringObject("select 1\r\n",10);
 719     shared.select2 = createStringObject("select 2\r\n",10);
 720     shared.select3 = createStringObject("select 3\r\n",10);
 721     shared.select4 = createStringObject("select 4\r\n",10);
 722     shared.select5 = createStringObject("select 5\r\n",10);
 723     shared.select6 = createStringObject("select 6\r\n",10);
 724     shared.select7 = createStringObject("select 7\r\n",10);
 725     shared.select8 = createStringObject("select 8\r\n",10);
 726     shared.select9 = createStringObject("select 9\r\n",10);
 727     shared.messagebulk = createStringObject("$7\r\nmessage\r\n",13);
 728     shared.pmessagebulk = createStringObject("$8\r\npmessage\r\n",14);
 729     shared.subscribebulk = createStringObject("$9\r\nsubscribe\r\n",15);
 730     shared.unsubscribebulk = createStringObject("$11\r\nunsubscribe\r\n",18);
 731     shared.psubscribebulk = createStringObject("$10\r\npsubscribe\r\n",17);
 732     shared.punsubscribebulk = createStringObject("$12\r\npunsubscribe\r\n",19);
 733     shared.mbulk3 = createStringObject("*3\r\n",4);
 734     shared.mbulk4 = createStringObject("*4\r\n",4);
 735     for (j = 0; j < REDIS_SHARED_INTEGERS; j++) {
 736         shared.integers[j] = createObject(REDIS_STRING,(void*)(long)j);
 737         shared.integers[j]->encoding = REDIS_ENCODING_INT;
 738     }
 739 }
 740
 741 void initServerConfig() {
 742     server.port = REDIS_SERVERPORT;
 743     server.bindaddr = NULL;
 744     server.unixsocket = NULL;
 745     server.ipfd = -1;
 746     server.sofd = -1;
 747     server.dbnum = REDIS_DEFAULT_DBNUM;
 748     server.verbosity = REDIS_VERBOSE;
 749     server.maxidletime = REDIS_MAXIDLETIME;
 750     server.saveparams = NULL;
 751     server.loading = 0;
 752     server.logfile = NULL; /* NULL = log on standard output */
 753     server.syslog_enabled = 0;
 754     server.syslog_ident = zstrdup("redis");
 755     server.syslog_facility = LOG_LOCAL0;
 756     server.glueoutputbuf = 1;
 757     server.daemonize = 0;
 758     server.appendonly = 0;
 759     server.appendfsync = APPENDFSYNC_EVERYSEC;
 760     server.no_appendfsync_on_rewrite = 0;
 761     server.lastfsync = time(NULL);
 762     server.appendfd = -1;
 763     server.appendseldb = -1; /* Make sure the first time will not match */
 764     server.pidfile = zstrdup("/var/run/redis.pid");
 765     server.dbfilename = zstrdup("dump.rdb");
 766     server.appendfilename = zstrdup("appendonly.aof");
 767     server.requirepass = NULL;
 768     server.rdbcompression = 1;
 769     server.activerehashing = 1;
 770     server.maxclients = 0;
 771     server.bpop_blocked_clients = 0;
 772     server.maxmemory = 0;
 773     server.maxmemory_policy = REDIS_MAXMEMORY_VOLATILE_LRU;
 774     server.maxmemory_samples = 3;
 775     server.ds_enabled = 0;
 776     server.ds_path = zstrdup("/tmp/redis.ds");
 777     server.cache_max_memory = 64LL*1024*1024; /* 64 MB of RAM */
 778     server.cache_blocked_clients = 0;
 779     server.hash_max_zipmap_entries = REDIS_HASH_MAX_ZIPMAP_ENTRIES;
 780     server.hash_max_zipmap_value = REDIS_HASH_MAX_ZIPMAP_VALUE;
 781     server.list_max_ziplist_entries = REDIS_LIST_MAX_ZIPLIST_ENTRIES;
 782     server.list_max_ziplist_value = REDIS_LIST_MAX_ZIPLIST_VALUE;
 783     server.set_max_intset_entries = REDIS_SET_MAX_INTSET_ENTRIES;
 784     server.shutdown_asap = 0;
 785
 786     updateLRUClock();
 787     resetServerSaveParams();
 788
 789     appendServerSaveParams(60*60,1);  /* save after 1 hour and 1 change */
 790     appendServerSaveParams(300,100);  /* save after 5 minutes and 100 changes */
 791     appendServerSaveParams(60,10000); /* save after 1 minute and 10000 changes */
 792     /* Replication related */
 793     server.isslave = 0;
 794     server.masterauth = NULL;
 795     server.masterhost = NULL;
 796     server.masterport = 6379;
 797     server.master = NULL;
 798     server.replstate = REDIS_REPL_NONE;
 799     server.repl_serve_stale_data = 1;
 800
 801     /* Double constants initialization */
 802     R_Zero = 0.0;
 803     R_PosInf = 1.0/R_Zero;
 804     R_NegInf = -1.0/R_Zero;
 805     R_Nan = R_Zero/R_Zero;
 806
 807     /* Command table -- we intiialize it here as it is part of the
 808      * initial configuration, since command names may be changed via
 809      * redis.conf using the rename-command directive. */
 810     server.commands = dictCreate(&commandTableDictType,NULL);
 811     populateCommandTable();
 812     server.delCommand = lookupCommandByCString("del");
 813     server.multiCommand = lookupCommandByCString("multi");
 814 }
 815
 816 void initServer() {
 817     int j;
 818
 819     signal(SIGHUP, SIG_IGN);
 820     signal(SIGPIPE, SIG_IGN);
 821     setupSigSegvAction();
 822
 823     if (server.syslog_enabled) {
 824         openlog(server.syslog_ident, LOG_PID | LOG_NDELAY | LOG_NOWAIT,
 825             server.syslog_facility);
 826     }
 827
 828     server.mainthread = pthread_self();
 829     server.clients = listCreate();
 830     server.slaves = listCreate();
 831     server.monitors = listCreate();
 832     server.unblocked_clients = listCreate();
 833     server.cache_flush_queue = listCreate();
 834     server.cache_flush_delay = 0;
 835
 836     createSharedObjects();
 837     server.el = aeCreateEventLoop();
 838     server.db = zmalloc(sizeof(redisDb)*server.dbnum);
 839     server.ipfd = anetTcpServer(server.neterr,server.port,server.bindaddr);
 840     if (server.ipfd == ANET_ERR) {
 841         redisLog(REDIS_WARNING, "Opening port: %s", server.neterr);
 842         exit(1);
 843     }
 844     if (server.unixsocket != NULL) {
 845         unlink(server.unixsocket); /* don't care if this fails */
 846         server.sofd = anetUnixServer(server.neterr,server.unixsocket);
 847         if (server.sofd == ANET_ERR) {
 848             redisLog(REDIS_WARNING, "Opening socket: %s", server.neterr);
 849             exit(1);
 850         }
 851     }
 852     if (server.ipfd < 0 && server.sofd < 0) {
 853         redisLog(REDIS_WARNING, "Configured to not listen anywhere, exiting.");
 854         exit(1);
 855     }
 856     for (j = 0; j < server.dbnum; j++) {
 857         server.db[j].dict = dictCreate(&dbDictType,NULL);
 858         server.db[j].expires = dictCreate(&keyptrDictType,NULL);
 859         server.db[j].blocking_keys = dictCreate(&keylistDictType,NULL);
 860         server.db[j].watched_keys = dictCreate(&keylistDictType,NULL);
 861         if (server.ds_enabled)
 862             server.db[j].io_keys = dictCreate(&keylistDictType,NULL);
 863         server.db[j].id = j;
 864     }
 865     server.pubsub_channels = dictCreate(&keylistDictType,NULL);
 866     server.pubsub_patterns = listCreate();
 867     listSetFreeMethod(server.pubsub_patterns,freePubsubPattern);
 868     listSetMatchMethod(server.pubsub_patterns,listMatchPubsubPattern);
 869     server.cronloops = 0;
 870     server.bgsavechildpid = -1;
 871     server.bgrewritechildpid = -1;
 872     server.bgrewritebuf = sdsempty();
 873     server.aofbuf = sdsempty();
 874     server.lastsave = time(NULL);
 875     server.dirty = 0;
 876     server.stat_numcommands = 0;
 877     server.stat_numconnections = 0;
 878     server.stat_expiredkeys = 0;
 879     server.stat_evictedkeys = 0;
 880     server.stat_starttime = time(NULL);
 881     server.stat_keyspace_misses = 0;
 882     server.stat_keyspace_hits = 0;
 883     server.unixtime = time(NULL);
 884     aeCreateTimeEvent(server.el, 1, serverCron, NULL, NULL);
 885     if (server.ipfd > 0 && aeCreateFileEvent(server.el,server.ipfd,AE_READABLE,
 886         acceptTcpHandler,NULL) == AE_ERR) oom("creating file event");
 887     if (server.sofd > 0 && aeCreateFileEvent(server.el,server.sofd,AE_READABLE,
 888         acceptUnixHandler,NULL) == AE_ERR) oom("creating file event");
 889
 890     if (server.appendonly) {
 891         server.appendfd = open(server.appendfilename,O_WRONLY|O_APPEND|O_CREAT,0644);
 892         if (server.appendfd == -1) {
 893             redisLog(REDIS_WARNING, "Can't open the append-only file: %s",
 894                 strerror(errno));
 895             exit(1);
 896         }
 897     }
 898
 899     if (server.ds_enabled) dsInit();
 900 }
 901
 902 /* Populates the Redis Command Table starting from the hard coded list
 903  * we have on top of redis.c file. */
 904 void populateCommandTable(void) {
 905     int j;
 906     int numcommands = sizeof(readonlyCommandTable)/sizeof(struct redisCommand);
 907
 908     for (j = 0; j < numcommands; j++) {
 909         struct redisCommand *c = readonlyCommandTable+j;
 910         int retval;
 911
 912         retval = dictAdd(server.commands, sdsnew(c->name), c);
 913         assert(retval == DICT_OK);
 914     }
 915 }
 916
 917 /* ====================== Commands lookup and execution ===================== */
 918
 919 struct redisCommand *lookupCommand(sds name) {
 920     return dictFetchValue(server.commands, name);
 921 }
 922
 923 struct redisCommand *lookupCommandByCString(char *s) {
 924     struct redisCommand *cmd;
 925     sds name = sdsnew(s);
 926
 927     cmd = dictFetchValue(server.commands, name);
 928     sdsfree(name);
 929     return cmd;
 930 }
 931
 932 /* Call() is the core of Redis execution of a command */
 933 void call(redisClient *c, struct redisCommand *cmd) {
 934     long long dirty;
 935
 936     dirty = server.dirty;
 937     cmd->proc(c);
 938     dirty = server.dirty-dirty;
 939
 940     if (server.appendonly && dirty)
 941         feedAppendOnlyFile(cmd,c->db->id,c->argv,c->argc);
 942     if ((dirty || cmd->flags & REDIS_CMD_FORCE_REPLICATION) &&
 943         listLength(server.slaves))
 944         replicationFeedSlaves(server.slaves,c->db->id,c->argv,c->argc);
 945     if (listLength(server.monitors))
 946         replicationFeedMonitors(server.monitors,c->db->id,c->argv,c->argc);
 947     server.stat_numcommands++;
 948 }
 949
 950 /* If this function gets called we already read a whole
 951  * command, argments are in the client argv/argc fields.
 952  * processCommand() execute the command or prepare the
 953  * server for a bulk read from the client.
 954  *
 955  * If 1 is returned the client is still alive and valid and
 956  * and other operations can be performed by the caller. Otherwise
 957  * if 0 is returned the client was destroied (i.e. after QUIT). */
 958 int processCommand(redisClient *c) {
 959     struct redisCommand *cmd;
 960
 961     /* The QUIT command is handled separately. Normal command procs will
 962      * go through checking for replication and QUIT will cause trouble
 963      * when FORCE_REPLICATION is enabled and would be implemented in
 964      * a regular command proc. */
 965     if (!strcasecmp(c->argv[0]->ptr,"quit")) {
 966         addReply(c,shared.ok);
 967         c->flags |= REDIS_CLOSE_AFTER_REPLY;
 968         return REDIS_ERR;
 969     }
 970
 971     /* Now lookup the command and check ASAP about trivial error conditions
 972      * such wrong arity, bad command name and so forth. */
 973     cmd = lookupCommand(c->argv[0]->ptr);
 974     if (!cmd) {
 975         addReplyErrorFormat(c,"unknown command '%s'",
 976             (char*)c->argv[0]->ptr);
 977         return REDIS_OK;
 978     } else if ((cmd->arity > 0 && cmd->arity != c->argc) ||
 979                (c->argc < -cmd->arity)) {
 980         addReplyErrorFormat(c,"wrong number of arguments for '%s' command",
 981             cmd->name);
 982         return REDIS_OK;
 983     }
 984
 985     /* Check if the user is authenticated */
 986     if (server.requirepass && !c->authenticated && cmd->proc != authCommand) {
 987         addReplyError(c,"operation not permitted");
 988         return REDIS_OK;
 989     }
 990
 991     /* Handle the maxmemory directive.
 992      *
 993      * First we try to free some memory if possible (if there are volatile
 994      * keys in the dataset). If there are not the only thing we can do
 995      * is returning an error. */
 996     if (server.maxmemory) freeMemoryIfNeeded();
 997     if (server.maxmemory && (cmd->flags & REDIS_CMD_DENYOOM) &&
 998         zmalloc_used_memory() > server.maxmemory)
 999     {
1000         addReplyError(c,"command not allowed when used memory > 'maxmemory'");
1001         return REDIS_OK;
1002     }
1003
1004     /* Only allow SUBSCRIBE and UNSUBSCRIBE in the context of Pub/Sub */
1005     if ((dictSize(c->pubsub_channels) > 0 || listLength(c->pubsub_patterns) > 0)
1006         &&
1007         cmd->proc != subscribeCommand && cmd->proc != unsubscribeCommand &&
1008         cmd->proc != psubscribeCommand && cmd->proc != punsubscribeCommand) {
1009         addReplyError(c,"only (P)SUBSCRIBE / (P)UNSUBSCRIBE / QUIT allowed in this context");
1010         return REDIS_OK;
1011     }
1012
1013     /* Only allow INFO and SLAVEOF when slave-serve-stale-data is no and
1014      * we are a slave with a broken link with master. */
1015     if (server.masterhost && server.replstate != REDIS_REPL_CONNECTED &&
1016         server.repl_serve_stale_data == 0 &&
1017         cmd->proc != infoCommand && cmd->proc != slaveofCommand)
1018     {
1019         addReplyError(c,
1020             "link with MASTER is down and slave-serve-stale-data is set to no");
1021         return REDIS_OK;
1022     }
1023
1024     /* Loading DB? Return an error if the command is not INFO */
1025     if (server.loading && cmd->proc != infoCommand) {
1026         addReply(c, shared.loadingerr);
1027         return REDIS_OK;
1028     }
1029
1030     /* Exec the command */
1031     if (c->flags & REDIS_MULTI &&
1032         cmd->proc != execCommand && cmd->proc != discardCommand &&
1033         cmd->proc != multiCommand && cmd->proc != watchCommand)
1034     {
1035         queueMultiCommand(c,cmd);
1036         addReply(c,shared.queued);
1037     } else {
1038         if (server.ds_enabled && blockClientOnSwappedKeys(c,cmd))
1039             return REDIS_ERR;
1040         call(c,cmd);
1041     }
1042     return REDIS_OK;
1043 }
1044
1045 /*================================== Shutdown =============================== */
1046
1047 int prepareForShutdown() {
1048     redisLog(REDIS_WARNING,"User requested shutdown, saving DB...");
1049     /* Kill the saving child if there is a background saving in progress.
1050        We want to avoid race conditions, for instance our saving child may
1051        overwrite the synchronous saving did by SHUTDOWN. */
1052     if (server.bgsavechildpid != -1) {
1053         redisLog(REDIS_WARNING,"There is a live saving child. Killing it!");
1054         kill(server.bgsavechildpid,SIGKILL);
1055         rdbRemoveTempFile(server.bgsavechildpid);
1056     }
1057     if (server.appendonly) {
1058         /* Append only file: fsync() the AOF and exit */
1059         aof_fsync(server.appendfd);
1060     } else if (server.saveparamslen > 0) {
1061         /* Snapshotting. Perform a SYNC SAVE and exit */
1062         if (rdbSave(server.dbfilename) != REDIS_OK) {
1063             /* Ooops.. error saving! The best we can do is to continue
1064              * operating. Note that if there was a background saving process,
1065              * in the next cron() Redis will be notified that the background
1066              * saving aborted, handling special stuff like slaves pending for
1067              * synchronization... */
1068             redisLog(REDIS_WARNING,"Error trying to save the DB, can't exit");
1069             return REDIS_ERR;
1070         }
1071     } else {
1072         redisLog(REDIS_WARNING,"Not saving DB.");
1073     }
1074     if (server.daemonize) unlink(server.pidfile);
1075     redisLog(REDIS_WARNING,"Server exit now, bye bye...");
1076     return REDIS_OK;
1077 }
1078
1079 /*================================== Commands =============================== */
1080
1081 void authCommand(redisClient *c) {
1082     if (!server.requirepass || !strcmp(c->argv[1]->ptr, server.requirepass)) {
1083       c->authenticated = 1;
1084       addReply(c,shared.ok);
1085     } else {
1086       c->authenticated = 0;
1087       addReplyError(c,"invalid password");
1088     }
1089 }
1090
1091 void pingCommand(redisClient *c) {
1092     addReply(c,shared.pong);
1093 }
1094
1095 void echoCommand(redisClient *c) {
1096     addReplyBulk(c,c->argv[1]);
1097 }
1098
1099 /* Convert an amount of bytes into a human readable string in the form
1100  * of 100B, 2G, 100M, 4K, and so forth. */
1101 void bytesToHuman(char *s, unsigned long long n) {
1102     double d;
1103
1104     if (n < 1024) {
1105         /* Bytes */
1106         sprintf(s,"%lluB",n);
1107         return;
1108     } else if (n < (1024*1024)) {
1109         d = (double)n/(1024);
1110         sprintf(s,"%.2fK",d);
1111     } else if (n < (1024LL*1024*1024)) {
1112         d = (double)n/(1024*1024);
1113         sprintf(s,"%.2fM",d);
1114     } else if (n < (1024LL*1024*1024*1024)) {
1115         d = (double)n/(1024LL*1024*1024);
1116         sprintf(s,"%.2fG",d);
1117     }
1118 }
1119
1120 /* Create the string returned by the INFO command. This is decoupled
1121  * by the INFO command itself as we need to report the same information
1122  * on memory corruption problems. */
1123 sds genRedisInfoString(void) {
1124     sds info;
1125     time_t uptime = time(NULL)-server.stat_starttime;
1126     int j;
1127     char hmem[64];
1128     struct rusage self_ru, c_ru;
1129
1130     getrusage(RUSAGE_SELF, &self_ru);
1131     getrusage(RUSAGE_CHILDREN, &c_ru);
1132
1133     bytesToHuman(hmem,zmalloc_used_memory());
1134     info = sdscatprintf(sdsempty(),
1135         "redis_version:%s\r\n"
1136         "redis_git_sha1:%s\r\n"
1137         "redis_git_dirty:%d\r\n"
1138         "arch_bits:%s\r\n"
1139         "multiplexing_api:%s\r\n"
1140         "process_id:%ld\r\n"
1141         "uptime_in_seconds:%ld\r\n"
1142         "uptime_in_days:%ld\r\n"
1143         "lru_clock:%ld\r\n"
1144         "used_cpu_sys:%.2f\r\n"
1145         "used_cpu_user:%.2f\r\n"
1146         "used_cpu_sys_childrens:%.2f\r\n"
1147         "used_cpu_user_childrens:%.2f\r\n"
1148         "connected_clients:%d\r\n"
1149         "connected_slaves:%d\r\n"
1150         "blocked_clients:%d\r\n"
1151         "used_memory:%zu\r\n"
1152         "used_memory_human:%s\r\n"
1153         "used_memory_rss:%zu\r\n"
1154         "mem_fragmentation_ratio:%.2f\r\n"
1155         "use_tcmalloc:%d\r\n"
1156         "loading:%d\r\n"
1157         "aof_enabled:%d\r\n"
1158         "changes_since_last_save:%lld\r\n"
1159         "bgsave_in_progress:%d\r\n"
1160         "last_save_time:%ld\r\n"
1161         "bgrewriteaof_in_progress:%d\r\n"
1162         "total_connections_received:%lld\r\n"
1163         "total_commands_processed:%lld\r\n"
1164         "expired_keys:%lld\r\n"
1165         "evicted_keys:%lld\r\n"
1166         "keyspace_hits:%lld\r\n"
1167         "keyspace_misses:%lld\r\n"
1168         "hash_max_zipmap_entries:%zu\r\n"
1169         "hash_max_zipmap_value:%zu\r\n"
1170         "pubsub_channels:%ld\r\n"
1171         "pubsub_patterns:%u\r\n"
1172         "ds_enabled:%d\r\n"
1173         "role:%s\r\n"
1174         ,REDIS_VERSION,
1175         redisGitSHA1(),
1176         strtol(redisGitDirty(),NULL,10) > 0,
1177         (sizeof(long) == 8) ? "64" : "32",
1178         aeGetApiName(),
1179         (long) getpid(),
1180         uptime,
1181         uptime/(3600*24),
1182         (unsigned long) server.lruclock,
1183         (float)self_ru.ru_utime.tv_sec+(float)self_ru.ru_utime.tv_usec/1000000,
1184         (float)self_ru.ru_stime.tv_sec+(float)self_ru.ru_stime.tv_usec/1000000,
1185         (float)c_ru.ru_utime.tv_sec+(float)c_ru.ru_utime.tv_usec/1000000,
1186         (float)c_ru.ru_stime.tv_sec+(float)c_ru.ru_stime.tv_usec/1000000,
1187         listLength(server.clients)-listLength(server.slaves),
1188         listLength(server.slaves),
1189         server.bpop_blocked_clients,
1190         zmalloc_used_memory(),
1191         hmem,
1192         zmalloc_get_rss(),
1193         zmalloc_get_fragmentation_ratio(),
1194 #ifdef USE_TCMALLOC
1195         1,
1196 #else
1197         0,
1198 #endif
1199         server.loading,
1200         server.appendonly,
1201         server.dirty,
1202         server.bgsavechildpid != -1,
1203         server.lastsave,
1204         server.bgrewritechildpid != -1,
1205         server.stat_numconnections,
1206         server.stat_numcommands,
1207         server.stat_expiredkeys,
1208         server.stat_evictedkeys,
1209         server.stat_keyspace_hits,
1210         server.stat_keyspace_misses,
1211         server.hash_max_zipmap_entries,
1212         server.hash_max_zipmap_value,
1213         dictSize(server.pubsub_channels),
1214         listLength(server.pubsub_patterns),
1215         server.ds_enabled != 0,
1216         server.masterhost == NULL ? "master" : "slave"
1217     );
1218     if (server.masterhost) {
1219         info = sdscatprintf(info,
1220             "master_host:%s\r\n"
1221             "master_port:%d\r\n"
1222             "master_link_status:%s\r\n"
1223             "master_last_io_seconds_ago:%d\r\n"
1224             "master_sync_in_progress:%d\r\n"
1225             ,server.masterhost,
1226             server.masterport,
1227             (server.replstate == REDIS_REPL_CONNECTED) ?
1228                 "up" : "down",
1229             server.master ? ((int)(time(NULL)-server.master->lastinteraction)) : -1,
1230             server.replstate == REDIS_REPL_TRANSFER
1231         );
1232
1233         if (server.replstate == REDIS_REPL_TRANSFER) {
1234             info = sdscatprintf(info,
1235                 "master_sync_left_bytes:%ld\r\n"
1236                 "master_sync_last_io_seconds_ago:%d\r\n"
1237                 ,(long)server.repl_transfer_left,
1238                 (int)(time(NULL)-server.repl_transfer_lastio)
1239             );
1240         }
1241     }
1242     if (server.ds_enabled) {
1243         lockThreadedIO();
1244         info = sdscatprintf(info,
1245             "cache_max_memory:%llu\r\n"
1246             "cache_blocked_clients:%lu\r\n"
1247             ,(unsigned long long) server.cache_max_memory,
1248             (unsigned long) server.cache_blocked_clients
1249         );
1250         unlockThreadedIO();
1251     }
1252     if (server.loading) {
1253         double perc;
1254         time_t eta, elapsed;
1255         off_t remaining_bytes = server.loading_total_bytes-
1256                                 server.loading_loaded_bytes;
1257
1258         perc = ((double)server.loading_loaded_bytes /
1259                server.loading_total_bytes) * 100;
1260
1261         elapsed = time(NULL)-server.loading_start_time;
1262         if (elapsed == 0) {
1263             eta = 1; /* A fake 1 second figure if we don't have enough info */
1264         } else {
1265             eta = (elapsed*remaining_bytes)/server.loading_loaded_bytes;
1266         }
1267
1268         info = sdscatprintf(info,
1269             "loading_start_time:%ld\r\n"
1270             "loading_total_bytes:%llu\r\n"
1271             "loading_loaded_bytes:%llu\r\n"
1272             "loading_loaded_perc:%.2f\r\n"
1273             "loading_eta_seconds:%ld\r\n"
1274             ,(unsigned long) server.loading_start_time,
1275             (unsigned long long) server.loading_total_bytes,
1276             (unsigned long long) server.loading_loaded_bytes,
1277             perc,
1278             eta
1279         );
1280     }
1281     for (j = 0; j < server.dbnum; j++) {
1282         long long keys, vkeys;
1283
1284         keys = dictSize(server.db[j].dict);
1285         vkeys = dictSize(server.db[j].expires);
1286         if (keys || vkeys) {
1287             info = sdscatprintf(info, "db%d:keys=%lld,expires=%lld\r\n",
1288                 j, keys, vkeys);
1289         }
1290     }
1291     return info;
1292 }
1293
1294 void infoCommand(redisClient *c) {
1295     sds info = genRedisInfoString();
1296     addReplySds(c,sdscatprintf(sdsempty(),"$%lu\r\n",
1297         (unsigned long)sdslen(info)));
1298     addReplySds(c,info);
1299     addReply(c,shared.crlf);
1300 }
1301
1302 void monitorCommand(redisClient *c) {
1303     /* ignore MONITOR if aleady slave or in monitor mode */
1304     if (c->flags & REDIS_SLAVE) return;
1305
1306     c->flags |= (REDIS_SLAVE|REDIS_MONITOR);
1307     c->slaveseldb = 0;
1308     listAddNodeTail(server.monitors,c);
1309     addReply(c,shared.ok);
1310 }
1311
1312 /* ============================ Maxmemory directive  ======================== */
1313
1314 /* This function gets called when 'maxmemory' is set on the config file to limit
1315  * the max memory used by the server, and we are out of memory.
1316  * This function will try to, in order:
1317  *
1318  * - Free objects from the free list
1319  * - Try to remove keys with an EXPIRE set
1320  *
1321  * It is not possible to free enough memory to reach used-memory < maxmemory
1322  * the server will start refusing commands that will enlarge even more the
1323  * memory usage.
1324  */
1325 void freeMemoryIfNeeded(void) {
1326     /* Remove keys accordingly to the active policy as long as we are
1327      * over the memory limit. */
1328     if (server.maxmemory_policy == REDIS_MAXMEMORY_NO_EVICTION) return;
1329
1330     while (server.maxmemory && zmalloc_used_memory() > server.maxmemory) {
1331         int j, k, freed = 0;
1332
1333         for (j = 0; j < server.dbnum; j++) {
1334             long bestval = 0; /* just to prevent warning */
1335             sds bestkey = NULL;
1336             struct dictEntry *de;
1337             redisDb *db = server.db+j;
1338             dict *dict;
1339
1340             if (server.maxmemory_policy == REDIS_MAXMEMORY_ALLKEYS_LRU ||
1341                 server.maxmemory_policy == REDIS_MAXMEMORY_ALLKEYS_RANDOM)
1342             {
1343                 dict = server.db[j].dict;
1344             } else {
1345                 dict = server.db[j].expires;
1346             }
1347             if (dictSize(dict) == 0) continue;
1348
1349             /* volatile-random and allkeys-random policy */
1350             if (server.maxmemory_policy == REDIS_MAXMEMORY_ALLKEYS_RANDOM ||
1351                 server.maxmemory_policy == REDIS_MAXMEMORY_VOLATILE_RANDOM)
1352             {
1353                 de = dictGetRandomKey(dict);
1354                 bestkey = dictGetEntryKey(de);
1355             }
1356
1357             /* volatile-lru and allkeys-lru policy */
1358             else if (server.maxmemory_policy == REDIS_MAXMEMORY_ALLKEYS_LRU ||
1359                 server.maxmemory_policy == REDIS_MAXMEMORY_VOLATILE_LRU)
1360             {
1361                 for (k = 0; k < server.maxmemory_samples; k++) {
1362                     sds thiskey;
1363                     long thisval;
1364                     robj *o;
1365
1366                     de = dictGetRandomKey(dict);
1367                     thiskey = dictGetEntryKey(de);
1368                     /* When policy is volatile-lru we need an additonal lookup
1369                      * to locate the real key, as dict is set to db->expires. */
1370                     if (server.maxmemory_policy == REDIS_MAXMEMORY_VOLATILE_LRU)
1371                         de = dictFind(db->dict, thiskey);
1372                     o = dictGetEntryVal(de);
1373                     thisval = estimateObjectIdleTime(o);
1374
1375                     /* Higher idle time is better candidate for deletion */
1376                     if (bestkey == NULL || thisval > bestval) {
1377                         bestkey = thiskey;
1378                         bestval = thisval;
1379                     }
1380                 }
1381             }
1382
1383             /* volatile-ttl */
1384             else if (server.maxmemory_policy == REDIS_MAXMEMORY_VOLATILE_TTL) {
1385                 for (k = 0; k < server.maxmemory_samples; k++) {
1386                     sds thiskey;
1387                     long thisval;
1388
1389                     de = dictGetRandomKey(dict);
1390                     thiskey = dictGetEntryKey(de);
1391                     thisval = (long) dictGetEntryVal(de);
1392
1393                     /* Expire sooner (minor expire unix timestamp) is better
1394                      * candidate for deletion */
1395                     if (bestkey == NULL || thisval < bestval) {
1396                         bestkey = thiskey;
1397                         bestval = thisval;
1398                     }
1399                 }
1400             }
1401
1402             /* Finally remove the selected key. */
1403             if (bestkey) {
1404                 robj *keyobj = createStringObject(bestkey,sdslen(bestkey));
1405                 dbDelete(db,keyobj);
1406                 server.stat_evictedkeys++;
1407                 decrRefCount(keyobj);
1408                 freed++;
1409             }
1410         }
1411         if (!freed) return; /* nothing to free... */
1412     }
1413 }
1414
1415 /* =================================== Main! ================================ */
1416
1417 #ifdef __linux__
1418 int linuxOvercommitMemoryValue(void) {
1419     FILE *fp = fopen("/proc/sys/vm/overcommit_memory","r");
1420     char buf[64];
1421
1422     if (!fp) return -1;
1423     if (fgets(buf,64,fp) == NULL) {
1424         fclose(fp);
1425         return -1;
1426     }
1427     fclose(fp);
1428
1429     return atoi(buf);
1430 }
1431
1432 void linuxOvercommitMemoryWarning(void) {
1433     if (linuxOvercommitMemoryValue() == 0) {
1434         redisLog(REDIS_WARNING,"WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.");
1435     }
1436 }
1437 #endif /* __linux__ */
1438
1439 void createPidFile(void) {
1440     /* Try to write the pid file in a best-effort way. */
1441     FILE *fp = fopen(server.pidfile,"w");
1442     if (fp) {
1443         fprintf(fp,"%d\n",getpid());
1444         fclose(fp);
1445     }
1446 }
1447
1448 void daemonize(void) {
1449     int fd;
1450
1451     if (fork() != 0) exit(0); /* parent exits */
1452     setsid(); /* create a new session */
1453
1454     /* Every output goes to /dev/null. If Redis is daemonized but
1455      * the 'logfile' is set to 'stdout' in the configuration file
1456      * it will not log at all. */
1457     if ((fd = open("/dev/null", O_RDWR, 0)) != -1) {
1458         dup2(fd, STDIN_FILENO);
1459         dup2(fd, STDOUT_FILENO);
1460         dup2(fd, STDERR_FILENO);
1461         if (fd > STDERR_FILENO) close(fd);
1462     }
1463 }
1464
1465 void version() {
1466     printf("Redis server version %s (%s:%d)\n", REDIS_VERSION,
1467         redisGitSHA1(), atoi(redisGitDirty()) > 0);
1468     exit(0);
1469 }
1470
1471 void usage() {
1472     fprintf(stderr,"Usage: ./redis-server [/path/to/redis.conf]\n");
1473     fprintf(stderr,"       ./redis-server - (read config from stdin)\n");
1474     exit(1);
1475 }
1476
1477 int main(int argc, char **argv) {
1478     time_t start;
1479
1480     initServerConfig();
1481     if (argc == 2) {
1482         if (strcmp(argv[1], "-v") == 0 ||
1483             strcmp(argv[1], "--version") == 0) version();
1484         if (strcmp(argv[1], "--help") == 0) usage();
1485         resetServerSaveParams();
1486         loadServerConfig(argv[1]);
1487     } else if ((argc > 2)) {
1488         usage();
1489     } else {
1490         redisLog(REDIS_WARNING,"Warning: no config file specified, using the default config. In order to specify a config file use 'redis-server /path/to/redis.conf'");
1491     }
1492     if (server.daemonize) daemonize();
1493     initServer();
1494     if (server.daemonize) createPidFile();
1495     redisLog(REDIS_NOTICE,"Server started, Redis version " REDIS_VERSION);
1496 #ifdef __linux__
1497     linuxOvercommitMemoryWarning();
1498 #endif
1499     start = time(NULL);
1500     if (server.appendonly) {
1501         if (loadAppendOnlyFile(server.appendfilename) == REDIS_OK)
1502             redisLog(REDIS_NOTICE,"DB loaded from append only file: %ld seconds",time(NULL)-start);
1503     } else {
1504         if (rdbLoad(server.dbfilename) == REDIS_OK)
1505             redisLog(REDIS_NOTICE,"DB loaded from disk: %ld seconds",time(NULL)-start);
1506     }
1507     if (server.ipfd > 0)
1508         redisLog(REDIS_NOTICE,"The server is now ready to accept connections on port %d", server.port);
1509     if (server.sofd > 0)
1510         redisLog(REDIS_NOTICE,"The server is now ready to accept connections at %s", server.unixsocket);
1511     aeSetBeforeSleepProc(server.el,beforeSleep);
1512     aeMain(server.el);
1513     aeDeleteEventLoop(server.el);
1514     return 0;
1515 }
1516
1517 /* ============================= Backtrace support ========================= */
1518
1519 #ifdef HAVE_BACKTRACE
1520 void *getMcontextEip(ucontext_t *uc) {
1521 #if defined(__FreeBSD__)
1522     return (void*) uc->uc_mcontext.mc_eip;
1523 #elif defined(__dietlibc__)
1524     return (void*) uc->uc_mcontext.eip;
1525 #elif defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
1526   #if __x86_64__
1527     return (void*) uc->uc_mcontext->__ss.__rip;
1528   #else
1529     return (void*) uc->uc_mcontext->__ss.__eip;
1530   #endif
1531 #elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
1532   #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
1533     return (void*) uc->uc_mcontext->__ss.__rip;
1534   #else
1535     return (void*) uc->uc_mcontext->__ss.__eip;
1536   #endif
1537 #elif defined(__i386__)
1538     return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
1539 #elif defined(__X86_64__) || defined(__x86_64__)
1540     return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
1541 #elif defined(__ia64__) /* Linux IA64 */
1542     return (void*) uc->uc_mcontext.sc_ip;
1543 #else
1544     return NULL;
1545 #endif
1546 }
1547
1548 void segvHandler(int sig, siginfo_t *info, void *secret) {
1549     void *trace[100];
1550     char **messages = NULL;
1551     int i, trace_size = 0;
1552     ucontext_t *uc = (ucontext_t*) secret;
1553     sds infostring;
1554     struct sigaction act;
1555     REDIS_NOTUSED(info);
1556
1557     redisLog(REDIS_WARNING,
1558         "======= Ooops! Redis %s got signal: -%d- =======", REDIS_VERSION, sig);
1559     infostring = genRedisInfoString();
1560     redisLog(REDIS_WARNING, "%s",infostring);
1561     /* It's not safe to sdsfree() the returned string under memory
1562      * corruption conditions. Let it leak as we are going to abort */
1563
1564     trace_size = backtrace(trace, 100);
1565     /* overwrite sigaction with caller's address */
1566     if (getMcontextEip(uc) != NULL) {
1567         trace[1] = getMcontextEip(uc);
1568     }
1569     messages = backtrace_symbols(trace, trace_size);
1570
1571     for (i=1; i<trace_size; ++i)
1572         redisLog(REDIS_WARNING,"%s", messages[i]);
1573
1574     /* free(messages); Don't call free() with possibly corrupted memory. */
1575     if (server.daemonize) unlink(server.pidfile);
1576
1577     /* Make sure we exit with the right signal at the end. So for instance
1578      * the core will be dumped if enabled. */
1579     sigemptyset (&act.sa_mask);
1580     /* When the SA_SIGINFO flag is set in sa_flags then sa_sigaction
1581      * is used. Otherwise, sa_handler is used */
1582     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
1583     act.sa_handler = SIG_DFL;
1584     sigaction (sig, &act, NULL);
1585     kill(getpid(),sig);
1586 }
1587
1588 void sigtermHandler(int sig) {
1589     REDIS_NOTUSED(sig);
1590
1591     redisLog(REDIS_WARNING,"SIGTERM received, scheduling shutting down...");
1592     server.shutdown_asap = 1;
1593 }
1594
1595 void setupSigSegvAction(void) {
1596     struct sigaction act;
1597
1598     sigemptyset (&act.sa_mask);
1599     /* When the SA_SIGINFO flag is set in sa_flags then sa_sigaction
1600      * is used. Otherwise, sa_handler is used */
1601     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
1602     act.sa_sigaction = segvHandler;
1603     sigaction (SIGSEGV, &act, NULL);
1604     sigaction (SIGBUS, &act, NULL);
1605     sigaction (SIGFPE, &act, NULL);
1606     sigaction (SIGILL, &act, NULL);
1607     sigaction (SIGBUS, &act, NULL);
1608
1609     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
1610     act.sa_handler = sigtermHandler;
1611     sigaction (SIGTERM, &act, NULL);
1612     return;
1613 }
1614
1615 #else /* HAVE_BACKTRACE */
1616 void setupSigSegvAction(void) {
1617 }
1618 #endif /* HAVE_BACKTRACE */
1619
1620 /* The End */