]> git.saurik.com Git - redis.git/blobdiff - redis.c
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[redis.git] / redis.c
diff --git a/redis.c b/redis.c
index 04c2c80b2711eafd55cb68fe50e460068017f8a5..f3db24265bcbedf56edc6e68298b92dd611fe092 100644 (file)
--- a/redis.c
+++ b/redis.c
@@ -27,7 +27,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-#define REDIS_VERSION "1.3.7"
+#define REDIS_VERSION "1.3.8"
 
 #include "fmacros.h"
 #include "config.h"
@@ -86,7 +86,7 @@
 #define REDIS_MAXIDLETIME       (60*5)  /* default client timeout */
 #define REDIS_IOBUF_LEN         1024
 #define REDIS_LOADBUF_LEN       1024
-#define REDIS_STATIC_ARGS       4
+#define REDIS_STATIC_ARGS       8
 #define REDIS_DEFAULT_DBNUM     16
 #define REDIS_CONFIGLINE_MAX    1024
 #define REDIS_OBJFREELIST_MAX   1000000 /* Max number of objects to cache */
    config file and the server is using more than maxmemory bytes of memory.
    In short this commands are denied on low memory conditions. */
 #define REDIS_CMD_DENYOOM       4
+#define REDIS_CMD_FORCE_REPLICATION 8 /* Force replication even if dirty is 0 */
 
 /* Object types */
 #define REDIS_STRING 0
@@ -327,6 +328,8 @@ typedef struct redisClient {
                              * is >= blockingto then the operation timed out. */
     list *io_keys;          /* Keys this client is waiting to be loaded from the
                              * swap file in order to continue. */
+    dict *pubsub_channels;  /* channels a client is interested in (SUBSCRIBE) */
+    list *pubsub_patterns;  /* patterns a client is interested in (SUBSCRIBE) */
 } redisClient;
 
 struct saveparam {
@@ -435,9 +438,18 @@ struct redisServer {
     unsigned long long vm_stats_swapped_objects;
     unsigned long long vm_stats_swapouts;
     unsigned long long vm_stats_swapins;
+    /* Pubsub */
+    dict *pubsub_channels; /* Map channels to list of subscribed clients */
+    list *pubsub_patterns; /* A list of pubsub_patterns */
+    /* Misc */
     FILE *devnull;
 };
 
+typedef struct pubsubPattern {
+    redisClient *client;
+    robj *pattern;
+} pubsubPattern;
+
 typedef void redisCommandProc(redisClient *c);
 struct redisCommand {
     char *name;
@@ -501,7 +513,9 @@ struct sharedObjectsStruct {
     *emptymultibulk, *wrongtypeerr, *nokeyerr, *syntaxerr, *sameobjecterr,
     *outofrangeerr, *plus,
     *select0, *select1, *select2, *select3, *select4,
-    *select5, *select6, *select7, *select8, *select9;
+    *select5, *select6, *select7, *select8, *select9,
+    *messagebulk, *subscribebulk, *unsubscribebulk, *mbulk3,
+    *psubscribebulk, *punsubscribebulk;
 } shared;
 
 /* Global vars that are actally used as constants. The following double
@@ -521,7 +535,7 @@ typedef struct iojob {
     robj *val;  /* the value to swap for REDIS_IOREQ_*_SWAP, otherwise this
                  * field is populated by the I/O thread for REDIS_IOREQ_LOAD. */
     off_t page; /* Swap page where to read/write the object */
-    off_t pages; /* Swap pages needed to safe object. PREPARE_SWAP return val */
+    off_t pages; /* Swap pages needed to save object. PREPARE_SWAP return val */
     int canceled; /* True if this command was canceled by blocking side of VM */
     pthread_t thread; /* ID of the thread processing this entry */
 } iojob;
@@ -541,7 +555,7 @@ static void incrRefCount(robj *o);
 static int rdbSaveBackground(char *filename);
 static robj *createStringObject(char *ptr, size_t len);
 static robj *dupStringObject(robj *o);
-static void replicationFeedSlaves(list *slaves, struct redisCommand *cmd, int dictid, robj **argv, int argc);
+static void replicationFeedSlaves(list *slaves, int dictid, robj **argv, int argc);
 static void feedAppendOnlyFile(struct redisCommand *cmd, int dictid, robj **argv, int argc);
 static int syncWithMaster(void);
 static robj *tryObjectSharing(robj *o);
@@ -601,6 +615,12 @@ static struct redisCommand *lookupCommand(char *name);
 static void call(redisClient *c, struct redisCommand *cmd);
 static void resetClient(redisClient *c);
 static void convertToRealHash(robj *o);
+static int pubsubUnsubscribeAllChannels(redisClient *c, int notify);
+static int pubsubUnsubscribeAllPatterns(redisClient *c, int notify);
+static void freePubsubPattern(void *p);
+static int listMatchPubsubPattern(void *a, void *b);
+static int compareStringObjects(robj *a, robj *b);
+static void usage();
 
 static void authCommand(redisClient *c);
 static void pingCommand(redisClient *c);
@@ -697,6 +717,12 @@ static void hvalsCommand(redisClient *c);
 static void hgetallCommand(redisClient *c);
 static void hexistsCommand(redisClient *c);
 static void configCommand(redisClient *c);
+static void hincrbyCommand(redisClient *c);
+static void subscribeCommand(redisClient *c);
+static void unsubscribeCommand(redisClient *c);
+static void psubscribeCommand(redisClient *c);
+static void punsubscribeCommand(redisClient *c);
+static void publishCommand(redisClient *c);
 
 /*================================= Globals ================================= */
 
@@ -756,6 +782,7 @@ static struct redisCommand cmdTable[] = {
     {"zrank",zrankCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
     {"zrevrank",zrevrankCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
     {"hset",hsetCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"hincrby",hincrbyCommand,4,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"hget",hgetCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
     {"hdel",hdelCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
     {"hlen",hlenCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
@@ -787,7 +814,7 @@ static struct redisCommand cmdTable[] = {
     {"lastsave",lastsaveCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
     {"type",typeCommand,2,REDIS_CMD_INLINE,NULL,1,1,1},
     {"multi",multiCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
-    {"exec",execCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"exec",execCommand,1,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,NULL,0,0,0},
     {"discard",discardCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
     {"sync",syncCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
     {"flushdb",flushdbCommand,1,REDIS_CMD_INLINE,NULL,0,0,0},
@@ -799,11 +826,14 @@ static struct redisCommand cmdTable[] = {
     {"slaveof",slaveofCommand,3,REDIS_CMD_INLINE,NULL,0,0,0},
     {"debug",debugCommand,-2,REDIS_CMD_INLINE,NULL,0,0,0},
     {"config",configCommand,-2,REDIS_CMD_BULK,NULL,0,0,0},
+    {"subscribe",subscribeCommand,-2,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"unsubscribe",unsubscribeCommand,-1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"psubscribe",psubscribeCommand,-2,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"punsubscribe",punsubscribeCommand,-1,REDIS_CMD_INLINE,NULL,0,0,0},
+    {"publish",publishCommand,3,REDIS_CMD_BULK|REDIS_CMD_FORCE_REPLICATION,NULL,0,0,0},
     {NULL,NULL,0,0,NULL,0,0,0}
 };
 
-static void usage();
-
 /*============================ Utility functions ============================ */
 
 /* Glob-style pattern matching. */
@@ -1139,7 +1169,9 @@ static void closeTimedoutClients(void) {
         if (server.maxidletime &&
             !(c->flags & REDIS_SLAVE) &&    /* no timeout for slaves */
             !(c->flags & REDIS_MASTER) &&   /* no timeout for masters */
-             (now - c->lastinteraction > server.maxidletime))
+            dictSize(c->pubsub_channels) == 0 && /* no timeout for pubsub */
+            listLength(c->pubsub_patterns) == 0 &&
+            (now - c->lastinteraction > server.maxidletime))
         {
             redisLog(REDIS_VERBOSE,"Closing idle client");
             freeClient(c);
@@ -1191,7 +1223,7 @@ void backgroundSaveDoneHandler(int statloc) {
         redisLog(REDIS_WARNING, "Background saving error");
     } else {
         redisLog(REDIS_WARNING,
-            "Background saving terminated by signal");
+            "Background saving terminated by signal %d", WTERMSIG(statloc));
         rdbRemoveTempFile(server.bgsavechildpid);
     }
     server.bgsavechildpid = -1;
@@ -1252,7 +1284,8 @@ void backgroundRewriteDoneHandler(int statloc) {
         redisLog(REDIS_WARNING, "Background append only file rewriting error");
     } else {
         redisLog(REDIS_WARNING,
-            "Background append only file rewriting terminated by signal");
+            "Background append only file rewriting terminated by signal %d",
+            WTERMSIG(statloc));
     }
 cleanup:
     sdsfree(server.bgrewritebuf);
@@ -1471,6 +1504,12 @@ static void createSharedObjects(void) {
     shared.select7 = createStringObject("select 7\r\n",10);
     shared.select8 = createStringObject("select 8\r\n",10);
     shared.select9 = createStringObject("select 9\r\n",10);
+    shared.messagebulk = createStringObject("$7\r\nmessage\r\n",13);
+    shared.subscribebulk = createStringObject("$9\r\nsubscribe\r\n",15);
+    shared.unsubscribebulk = createStringObject("$11\r\nunsubscribe\r\n",18);
+    shared.psubscribebulk = createStringObject("$10\r\npsubscribe\r\n",17);
+    shared.punsubscribebulk = createStringObject("$12\r\npunsubscribe\r\n",19);
+    shared.mbulk3 = createStringObject("*3\r\n",4);
 }
 
 static void appendServerSaveParams(time_t seconds, int changes) {
@@ -1574,6 +1613,10 @@ static void initServer() {
             server.db[j].io_keys = dictCreate(&keylistDictType,NULL);
         server.db[j].id = j;
     }
+    server.pubsub_channels = dictCreate(&keylistDictType,NULL);
+    server.pubsub_patterns = listCreate();
+    listSetFreeMethod(server.pubsub_patterns,freePubsubPattern);
+    listSetMatchMethod(server.pubsub_patterns,listMatchPubsubPattern);
     server.cronloops = 0;
     server.bgsavechildpid = -1;
     server.bgrewritechildpid = -1;
@@ -1837,6 +1880,12 @@ static void freeClient(redisClient *c) {
     if (c->flags & REDIS_BLOCKED)
         unblockClientWaitingData(c);
 
+    /* Unsubscribe from all the pubsub channels */
+    pubsubUnsubscribeAllChannels(c,0);
+    pubsubUnsubscribeAllPatterns(c,0);
+    dictRelease(c->pubsub_channels);
+    listRelease(c->pubsub_patterns);
+    /* Obvious cleanup */
     aeDeleteFileEvent(server.el,c->fd,AE_READABLE);
     aeDeleteFileEvent(server.el,c->fd,AE_WRITABLE);
     listRelease(c->reply);
@@ -1859,7 +1908,7 @@ static void freeClient(redisClient *c) {
         dontWaitForSwappedKey(c,ln->value);
     }
     listRelease(c->io_keys);
-    /* Other cleanup */
+    /* Master/slave cleanup */
     if (c->flags & REDIS_SLAVE) {
         if (c->replstate == REDIS_REPL_SEND_BULK && c->repldbfd != -1)
             close(c->repldbfd);
@@ -1872,6 +1921,7 @@ static void freeClient(redisClient *c) {
         server.master = NULL;
         server.replstate = REDIS_REPL_CONNECT;
     }
+    /* Release memory */
     zfree(c->argv);
     zfree(c->mbargv);
     freeClientMultiState(c);
@@ -2072,12 +2122,15 @@ static void call(redisClient *c, struct redisCommand *cmd) {
 
     dirty = server.dirty;
     cmd->proc(c);
-    if (server.appendonly && server.dirty-dirty)
+    dirty = server.dirty-dirty;
+
+    if (server.appendonly && dirty)
         feedAppendOnlyFile(cmd,c->db->id,c->argv,c->argc);
-    if (server.dirty-dirty && listLength(server.slaves))
-        replicationFeedSlaves(server.slaves,cmd,c->db->id,c->argv,c->argc);
+    if ((dirty || cmd->flags & REDIS_CMD_FORCE_REPLICATION) &&
+        listLength(server.slaves))
+        replicationFeedSlaves(server.slaves,c->db->id,c->argv,c->argc);
     if (listLength(server.monitors))
-        replicationFeedSlaves(server.monitors,cmd,c->db->id,c->argv,c->argc);
+        replicationFeedSlaves(server.monitors,c->db->id,c->argv,c->argc);
     server.stat_numcommands++;
 }
 
@@ -2187,10 +2240,6 @@ static int processCommand(redisClient *c) {
                 cmd->name));
         resetClient(c);
         return 1;
-    } else if (server.maxmemory && cmd->flags & REDIS_CMD_DENYOOM && zmalloc_used_memory() > server.maxmemory) {
-        addReplySds(c,sdsnew("-ERR command not allowed when used memory > 'maxmemory'\r\n"));
-        resetClient(c);
-        return 1;
     } else if (cmd->flags & REDIS_CMD_BULK && c->bulklen == -1) {
         /* This is a bulk command, we have to read the last argument yet. */
         int bulklen = atoi(c->argv[c->argc-1]->ptr);
@@ -2236,6 +2285,24 @@ static int processCommand(redisClient *c) {
         return 1;
     }
 
+    /* Handle the maxmemory directive */
+    if (server.maxmemory && (cmd->flags & REDIS_CMD_DENYOOM) &&
+        zmalloc_used_memory() > server.maxmemory)
+    {
+        addReplySds(c,sdsnew("-ERR command not allowed when used memory > 'maxmemory'\r\n"));
+        resetClient(c);
+        return 1;
+    }
+
+    /* Only allow SUBSCRIBE and UNSUBSCRIBE in the context of Pub/Sub */
+    if (dictSize(c->pubsub_channels) > 0 &&
+        cmd->proc != subscribeCommand && cmd->proc != unsubscribeCommand &&
+        cmd->proc != psubscribeCommand && cmd->proc != punsubscribeCommand) {
+        addReplySds(c,sdsnew("-ERR only (P)SUBSCRIBE / (P)UNSUBSCRIBE / QUIT allowed in this context\r\n"));
+        resetClient(c);
+        return 1;
+    }
+
     /* Exec the command */
     if (c->flags & REDIS_MULTI && cmd->proc != execCommand && cmd->proc != discardCommand) {
         queueMultiCommand(c,cmd);
@@ -2251,34 +2318,36 @@ static int processCommand(redisClient *c) {
     return 1;
 }
 
-static void replicationFeedSlaves(list *slaves, struct redisCommand *cmd, int dictid, robj **argv, int argc) {
+static void replicationFeedSlaves(list *slaves, int dictid, robj **argv, int argc) {
     listNode *ln;
     listIter li;
     int outc = 0, j;
     robj **outv;
-    /* (args*2)+1 is enough room for args, spaces, newlines */
-    robj *static_outv[REDIS_STATIC_ARGS*2+1];
+    /* We need 1+(ARGS*3) objects since commands are using the new protocol
+     * and we one 1 object for the first "*<count>\r\n" multibulk count, then
+     * for every additional object we have "$<count>\r\n" + object + "\r\n". */
+    robj *static_outv[REDIS_STATIC_ARGS*3+1];
+    robj *lenobj;
 
     if (argc <= REDIS_STATIC_ARGS) {
         outv = static_outv;
     } else {
-        outv = zmalloc(sizeof(robj*)*(argc*2+1));
+        outv = zmalloc(sizeof(robj*)*(argc*3+1));
     }
-    
-    for (j = 0; j < argc; j++) {
-        if (j != 0) outv[outc++] = shared.space;
-        if ((cmd->flags & REDIS_CMD_BULK) && j == argc-1) {
-            robj *lenobj;
 
-            lenobj = createObject(REDIS_STRING,
-                sdscatprintf(sdsempty(),"%lu\r\n",
-                    (unsigned long) stringObjectLen(argv[j])));
-            lenobj->refcount = 0;
-            outv[outc++] = lenobj;
-        }
+    lenobj = createObject(REDIS_STRING,
+            sdscatprintf(sdsempty(), "*%d\r\n", argc));
+    lenobj->refcount = 0;
+    outv[outc++] = lenobj;
+    for (j = 0; j < argc; j++) {
+        lenobj = createObject(REDIS_STRING,
+            sdscatprintf(sdsempty(),"$%lu\r\n",
+                (unsigned long) stringObjectLen(argv[j])));
+        lenobj->refcount = 0;
+        outv[outc++] = lenobj;
         outv[outc++] = argv[j];
+        outv[outc++] = shared.crlf;
     }
-    outv[outc++] = shared.crlf;
 
     /* Increment all the refcounts at start and decrement at end in order to
      * be sure to free objects if there is no slave in a replication state
@@ -2430,8 +2499,7 @@ static void readQueryFromClient(aeEventLoop *el, int fd, void *privdata, int mas
     } else {
         return;
     }
-    if (!(c->flags & REDIS_BLOCKED))
-        processInputBuffer(c);
+    processInputBuffer(c);
 }
 
 static int selectDb(redisClient *c, int id) {
@@ -2446,6 +2514,10 @@ static void *dupClientReplyValue(void *o) {
     return o;
 }
 
+static int listMatchObjects(void *a, void *b) {
+    return compareStringObjects(a,b) == 0;
+}
+
 static redisClient *createClient(int fd) {
     redisClient *c = zmalloc(sizeof(*c));
 
@@ -2473,6 +2545,10 @@ static redisClient *createClient(int fd) {
     c->blockingkeysnum = 0;
     c->io_keys = listCreate();
     listSetFreeMethod(c->io_keys,decrRefCount);
+    c->pubsub_channels = dictCreate(&setDictType,NULL);
+    c->pubsub_patterns = listCreate();
+    listSetFreeMethod(c->pubsub_patterns,decrRefCount);
+    listSetMatchMethod(c->pubsub_patterns,listMatchObjects);
     if (aeCreateFileEvent(server.el, c->fd, AE_READABLE,
         readQueryFromClient, c) == AE_ERR) {
         freeClient(c);
@@ -5016,7 +5092,7 @@ static int zslRandomLevel(void) {
     int level = 1;
     while ((random()&0xFFFF) < (ZSKIPLIST_P * 0xFFFF))
         level += 1;
-    return level;
+    return (level<ZSKIPLIST_MAXLEVEL) ? level : ZSKIPLIST_MAXLEVEL;
 }
 
 static void zslInsert(zskiplist *zsl, double score, robj *obj) {
@@ -5614,7 +5690,7 @@ static void zunionInterGenericCommand(redisClient *c, robj *dstkey, int op) {
         addReplyLong(c, dstzset->zsl->length);
         server.dirty++;
     } else {
-        decrRefCount(dstzset);
+        decrRefCount(dstobj);
         addReply(c, shared.czero);
     }
     zfree(src);
@@ -5929,10 +6005,8 @@ static void hsetCommand(redisClient *c) {
         decrRefCount(valobj);
         o->ptr = zm;
 
-        /* And here there is the second check for hash conversion...
-         * we want to do it only if the operation was not just an update as
-         * zipmapLen() is O(N). */
-        if (!update && zipmapLen(zm) > server.hash_max_zipmap_entries)
+        /* And here there is the second check for hash conversion. */
+        if (zipmapLen(zm) > server.hash_max_zipmap_entries)
             convertToRealHash(o);
     } else {
         tryObjectEncoding(c->argv[2]);
@@ -5949,6 +6023,78 @@ static void hsetCommand(redisClient *c) {
     addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",update == 0));
 }
 
+static void hincrbyCommand(redisClient *c) {
+    long long value = 0, incr = 0;
+    robj *o = lookupKeyWrite(c->db,c->argv[1]);
+
+    if (o == NULL) {
+        o = createHashObject();
+        dictAdd(c->db->dict,c->argv[1],o);
+        incrRefCount(c->argv[1]);
+    } else {
+        if (o->type != REDIS_HASH) {
+            addReply(c,shared.wrongtypeerr);
+            return;
+        }
+    }
+
+    robj *o_incr = getDecodedObject(c->argv[3]);
+    incr = strtoll(o_incr->ptr, NULL, 10);
+    decrRefCount(o_incr);
+
+    if (o->encoding == REDIS_ENCODING_ZIPMAP) {
+        unsigned char *zm = o->ptr;
+        unsigned char *zval;
+        unsigned int zvlen;
+
+        /* Find value if already present in hash */
+        if (zipmapGet(zm,c->argv[2]->ptr,sdslen(c->argv[2]->ptr),
+            &zval,&zvlen)) {
+            /* strtoll needs the char* to have a trailing \0, but
+             * the zipmap doesn't include them. */
+            sds szval = sdsnewlen(zval, zvlen);
+            value = strtoll(szval,NULL,10);
+            sdsfree(szval);
+        }
+
+        value += incr;
+        sds svalue = sdscatprintf(sdsempty(),"%lld",value);
+        zm = zipmapSet(zm,c->argv[2]->ptr,sdslen(c->argv[2]->ptr),
+            (unsigned char*)svalue,sdslen(svalue),NULL);
+        sdsfree(svalue);
+        o->ptr = zm;
+
+        /* Check if the zipmap needs to be converted. */
+        if (zipmapLen(zm) > server.hash_max_zipmap_entries)
+            convertToRealHash(o);
+    } else {
+        robj *hval;
+        dictEntry *de;
+
+        /* Find value if already present in hash */
+        de = dictFind(o->ptr,c->argv[2]);
+        if (de != NULL) {
+            hval = dictGetEntryVal(de);
+            if (hval->encoding == REDIS_ENCODING_RAW)
+                value = strtoll(hval->ptr,NULL,10);
+            else if (hval->encoding == REDIS_ENCODING_INT)
+                value = (long)hval->ptr;
+            else
+                redisAssert(1 != 1);
+        }
+
+        value += incr;
+        hval = createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",value));
+        tryObjectEncoding(hval);
+        if (dictReplace(o->ptr,c->argv[2],hval)) {
+            incrRefCount(c->argv[2]);
+        }
+    }
+
+    server.dirty++;
+    addReplyLong(c, value);
+}
+
 static void hgetCommand(redisClient *c) {
     robj *o;
 
@@ -6562,6 +6708,8 @@ static sds genRedisInfoString(void) {
         "expired_keys:%lld\r\n"
         "hash_max_zipmap_entries:%ld\r\n"
         "hash_max_zipmap_value:%ld\r\n"
+        "pubsub_channels:%ld\r\n"
+        "pubsub_patterns:%u\r\n"
         "vm_enabled:%d\r\n"
         "role:%s\r\n"
         ,REDIS_VERSION,
@@ -6584,6 +6732,8 @@ static sds genRedisInfoString(void) {
         server.stat_expiredkeys,
         server.hash_max_zipmap_entries,
         server.hash_max_zipmap_value,
+        dictSize(server.pubsub_channels),
+        listLength(server.pubsub_patterns),
         server.vm_enabled != 0,
         server.masterhost == NULL ? "master" : "slave"
     );
@@ -9154,6 +9304,265 @@ badarity:
         (char*) c->argv[1]->ptr));
 }
 
+/* =========================== Pubsub implementation ======================== */
+
+static void freePubsubPattern(void *p) {
+    pubsubPattern *pat = p;
+
+    decrRefCount(pat->pattern);
+    zfree(pat);
+}
+
+static int listMatchPubsubPattern(void *a, void *b) {
+    pubsubPattern *pa = a, *pb = b;
+
+    return (pa->client == pb->client) &&
+           (compareStringObjects(pa->pattern,pb->pattern) == 0);
+}
+
+/* Subscribe a client to a channel. Returns 1 if the operation succeeded, or
+ * 0 if the client was already subscribed to that channel. */
+static int pubsubSubscribeChannel(redisClient *c, robj *channel) {
+    struct dictEntry *de;
+    list *clients = NULL;
+    int retval = 0;
+
+    /* Add the channel to the client -> channels hash table */
+    if (dictAdd(c->pubsub_channels,channel,NULL) == DICT_OK) {
+        retval = 1;
+        incrRefCount(channel);
+        /* Add the client to the channel -> list of clients hash table */
+        de = dictFind(server.pubsub_channels,channel);
+        if (de == NULL) {
+            clients = listCreate();
+            dictAdd(server.pubsub_channels,channel,clients);
+            incrRefCount(channel);
+        } else {
+            clients = dictGetEntryVal(de);
+        }
+        listAddNodeTail(clients,c);
+    }
+    /* Notify the client */
+    addReply(c,shared.mbulk3);
+    addReply(c,shared.subscribebulk);
+    addReplyBulk(c,channel);
+    addReplyLong(c,dictSize(c->pubsub_channels)+listLength(c->pubsub_patterns));
+    return retval;
+}
+
+/* Unsubscribe a client from a channel. Returns 1 if the operation succeeded, or
+ * 0 if the client was not subscribed to the specified channel. */
+static int pubsubUnsubscribeChannel(redisClient *c, robj *channel, int notify) {
+    struct dictEntry *de;
+    list *clients;
+    listNode *ln;
+    int retval = 0;
+
+    /* Remove the channel from the client -> channels hash table */
+    incrRefCount(channel); /* channel may be just a pointer to the same object
+                            we have in the hash tables. Protect it... */
+    if (dictDelete(c->pubsub_channels,channel) == DICT_OK) {
+        retval = 1;
+        /* Remove the client from the channel -> clients list hash table */
+        de = dictFind(server.pubsub_channels,channel);
+        assert(de != NULL);
+        clients = dictGetEntryVal(de);
+        ln = listSearchKey(clients,c);
+        assert(ln != NULL);
+        listDelNode(clients,ln);
+        if (listLength(clients) == 0) {
+            /* Free the list and associated hash entry at all if this was
+             * the latest client, so that it will be possible to abuse
+             * Redis PUBSUB creating millions of channels. */
+            dictDelete(server.pubsub_channels,channel);
+        }
+    }
+    /* Notify the client */
+    if (notify) {
+        addReply(c,shared.mbulk3);
+        addReply(c,shared.unsubscribebulk);
+        addReplyBulk(c,channel);
+        addReplyLong(c,dictSize(c->pubsub_channels)+
+                       listLength(c->pubsub_patterns));
+
+    }
+    decrRefCount(channel); /* it is finally safe to release it */
+    return retval;
+}
+
+/* Subscribe a client to a pattern. Returns 1 if the operation succeeded, or 0 if the clinet was already subscribed to that pattern. */
+static int pubsubSubscribePattern(redisClient *c, robj *pattern) {
+    int retval = 0;
+
+    if (listSearchKey(c->pubsub_patterns,pattern) == NULL) {
+        retval = 1;
+        pubsubPattern *pat;
+        listAddNodeTail(c->pubsub_patterns,pattern);
+        incrRefCount(pattern);
+        pat = zmalloc(sizeof(*pat));
+        pat->pattern = getDecodedObject(pattern);
+        pat->client = c;
+        listAddNodeTail(server.pubsub_patterns,pat);
+    }
+    /* Notify the client */
+    addReply(c,shared.mbulk3);
+    addReply(c,shared.psubscribebulk);
+    addReplyBulk(c,pattern);
+    addReplyLong(c,dictSize(c->pubsub_channels)+listLength(c->pubsub_patterns));
+    return retval;
+}
+
+/* Unsubscribe a client from a channel. Returns 1 if the operation succeeded, or
+ * 0 if the client was not subscribed to the specified channel. */
+static int pubsubUnsubscribePattern(redisClient *c, robj *pattern, int notify) {
+    listNode *ln;
+    pubsubPattern pat;
+    int retval = 0;
+
+    incrRefCount(pattern); /* Protect the object. May be the same we remove */
+    if ((ln = listSearchKey(c->pubsub_patterns,pattern)) != NULL) {
+        retval = 1;
+        listDelNode(c->pubsub_patterns,ln);
+        pat.client = c;
+        pat.pattern = pattern;
+        ln = listSearchKey(server.pubsub_patterns,&pat);
+        listDelNode(server.pubsub_patterns,ln);
+    }
+    /* Notify the client */
+    if (notify) {
+        addReply(c,shared.mbulk3);
+        addReply(c,shared.punsubscribebulk);
+        addReplyBulk(c,pattern);
+        addReplyLong(c,dictSize(c->pubsub_channels)+
+                       listLength(c->pubsub_patterns));
+    }
+    decrRefCount(pattern);
+    return retval;
+}
+
+/* Unsubscribe from all the channels. Return the number of channels the
+ * client was subscribed from. */
+static int pubsubUnsubscribeAllChannels(redisClient *c, int notify) {
+    dictIterator *di = dictGetIterator(c->pubsub_channels);
+    dictEntry *de;
+    int count = 0;
+
+    while((de = dictNext(di)) != NULL) {
+        robj *channel = dictGetEntryKey(de);
+
+        count += pubsubUnsubscribeChannel(c,channel,notify);
+    }
+    dictReleaseIterator(di);
+    return count;
+}
+
+/* Unsubscribe from all the patterns. Return the number of patterns the
+ * client was subscribed from. */
+static int pubsubUnsubscribeAllPatterns(redisClient *c, int notify) {
+    listNode *ln;
+    listIter li;
+    int count = 0;
+
+    listRewind(c->pubsub_patterns,&li);
+    while ((ln = listNext(&li)) != NULL) {
+        robj *pattern = ln->value;
+
+        count += pubsubUnsubscribePattern(c,pattern,notify);
+    }
+    return count;
+}
+
+/* Publish a message */
+static int pubsubPublishMessage(robj *channel, robj *message) {
+    int receivers = 0;
+    struct dictEntry *de;
+    listNode *ln;
+    listIter li;
+
+    /* Send to clients listening for that channel */
+    de = dictFind(server.pubsub_channels,channel);
+    if (de) {
+        list *list = dictGetEntryVal(de);
+        listNode *ln;
+        listIter li;
+
+        listRewind(list,&li);
+        while ((ln = listNext(&li)) != NULL) {
+            redisClient *c = ln->value;
+
+            addReply(c,shared.mbulk3);
+            addReply(c,shared.messagebulk);
+            addReplyBulk(c,channel);
+            addReplyBulk(c,message);
+            receivers++;
+        }
+    }
+    /* Send to clients listening to matching channels */
+    if (listLength(server.pubsub_patterns)) {
+        listRewind(server.pubsub_patterns,&li);
+        channel = getDecodedObject(channel);
+        while ((ln = listNext(&li)) != NULL) {
+            pubsubPattern *pat = ln->value;
+
+            if (stringmatchlen((char*)pat->pattern->ptr,
+                                sdslen(pat->pattern->ptr),
+                                (char*)channel->ptr,
+                                sdslen(channel->ptr),0)) {
+                addReply(pat->client,shared.mbulk3);
+                addReply(pat->client,shared.messagebulk);
+                addReplyBulk(pat->client,channel);
+                addReplyBulk(pat->client,message);
+                receivers++;
+            }
+        }
+        decrRefCount(channel);
+    }
+    return receivers;
+}
+
+static void subscribeCommand(redisClient *c) {
+    int j;
+
+    for (j = 1; j < c->argc; j++)
+        pubsubSubscribeChannel(c,c->argv[j]);
+}
+
+static void unsubscribeCommand(redisClient *c) {
+    if (c->argc == 1) {
+        pubsubUnsubscribeAllChannels(c,1);
+        return;
+    } else {
+        int j;
+
+        for (j = 1; j < c->argc; j++)
+            pubsubUnsubscribeChannel(c,c->argv[j],1);
+    }
+}
+
+static void psubscribeCommand(redisClient *c) {
+    int j;
+
+    for (j = 1; j < c->argc; j++)
+        pubsubSubscribePattern(c,c->argv[j]);
+}
+
+static void punsubscribeCommand(redisClient *c) {
+    if (c->argc == 1) {
+        pubsubUnsubscribeAllPatterns(c,1);
+        return;
+    } else {
+        int j;
+
+        for (j = 1; j < c->argc; j++)
+            pubsubUnsubscribePattern(c,c->argv[j],1);
+    }
+}
+
+static void publishCommand(redisClient *c) {
+    int receivers = pubsubPublishMessage(c->argv[1],c->argv[2]);
+    addReplyLong(c,receivers);
+}
+
 /* ================================= Debugging ============================== */
 
 static void debugCommand(redisClient *c) {