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1 files changed, 371 insertions, 0 deletions

diff --git a/src/pubsub.c b/src/pubsub.c
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+/*
+ * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "server.h"
+
+/*-----------------------------------------------------------------------------
+ * Pubsub low level API
+ *----------------------------------------------------------------------------*/
+
+void freePubsubPattern(void *p) {
+    pubsubPattern *pat = p;
+
+    decrRefCount(pat->pattern);
+    zfree(pat);
+}
+
+int listMatchPubsubPattern(void *a, void *b) {
+    pubsubPattern *pa = a, *pb = b;
+
+    return (pa->client == pb->client) &&
+           (equalStringObjects(pa->pattern,pb->pattern));
+}
+
+/* Return the number of channels + patterns a client is subscribed to. */
+int clientSubscriptionsCount(client *c) {
+    return dictSize(c->pubsub_channels)+
+           listLength(c->pubsub_patterns);
+}
+
+/* Subscribe a client to a channel. Returns 1 if the operation succeeded, or
+ * 0 if the client was already subscribed to that channel. */
+int pubsubSubscribeChannel(client *c, robj *channel) {
+    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 = dictGetVal(de);
+        }
+        listAddNodeTail(clients,c);
+    }
+    /* Notify the client */
+    addReply(c,shared.mbulkhdr[3]);
+    addReply(c,shared.subscribebulk);
+    addReplyBulk(c,channel);
+    addReplyLongLong(c,clientSubscriptionsCount(c));
+    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. */
+int pubsubUnsubscribeChannel(client *c, robj *channel, int notify) {
+    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);
+        serverAssertWithInfo(c,NULL,de != NULL);
+        clients = dictGetVal(de);
+        ln = listSearchKey(clients,c);
+        serverAssertWithInfo(c,NULL,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.mbulkhdr[3]);
+        addReply(c,shared.unsubscribebulk);
+        addReplyBulk(c,channel);
+        addReplyLongLong(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 client was already subscribed to that pattern. */
+int pubsubSubscribePattern(client *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.mbulkhdr[3]);
+    addReply(c,shared.psubscribebulk);
+    addReplyBulk(c,pattern);
+    addReplyLongLong(c,clientSubscriptionsCount(c));
+    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. */
+int pubsubUnsubscribePattern(client *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.mbulkhdr[3]);
+        addReply(c,shared.punsubscribebulk);
+        addReplyBulk(c,pattern);
+        addReplyLongLong(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 to. */
+int pubsubUnsubscribeAllChannels(client *c, int notify) {
+    dictIterator *di = dictGetSafeIterator(c->pubsub_channels);
+    dictEntry *de;
+    int count = 0;
+
+    while((de = dictNext(di)) != NULL) {
+        robj *channel = dictGetKey(de);
+
+        count += pubsubUnsubscribeChannel(c,channel,notify);
+    }
+    /* We were subscribed to nothing? Still reply to the client. */
+    if (notify && count == 0) {
+        addReply(c,shared.mbulkhdr[3]);
+        addReply(c,shared.unsubscribebulk);
+        addReply(c,shared.nullbulk);
+        addReplyLongLong(c,dictSize(c->pubsub_channels)+
+                       listLength(c->pubsub_patterns));
+    }
+    dictReleaseIterator(di);
+    return count;
+}
+
+/* Unsubscribe from all the patterns. Return the number of patterns the
+ * client was subscribed from. */
+int pubsubUnsubscribeAllPatterns(client *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);
+    }
+    if (notify && count == 0) {
+        /* We were subscribed to nothing? Still reply to the client. */
+        addReply(c,shared.mbulkhdr[3]);
+        addReply(c,shared.punsubscribebulk);
+        addReply(c,shared.nullbulk);
+        addReplyLongLong(c,dictSize(c->pubsub_channels)+
+                       listLength(c->pubsub_patterns));
+    }
+    return count;
+}
+
+/* Publish a message */
+int pubsubPublishMessage(robj *channel, robj *message) {
+    int receivers = 0;
+    dictEntry *de;
+    listNode *ln;
+    listIter li;
+
+    /* Send to clients listening for that channel */
+    de = dictFind(server.pubsub_channels,channel);
+    if (de) {
+        list *list = dictGetVal(de);
+        listNode *ln;
+        listIter li;
+
+        listRewind(list,&li);
+        while ((ln = listNext(&li)) != NULL) {
+            client *c = ln->value;
+
+            addReply(c,shared.mbulkhdr[3]);
+            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.mbulkhdr[4]);
+                addReply(pat->client,shared.pmessagebulk);
+                addReplyBulk(pat->client,pat->pattern);
+                addReplyBulk(pat->client,channel);
+                addReplyBulk(pat->client,message);
+                receivers++;
+            }
+        }
+        decrRefCount(channel);
+    }
+    return receivers;
+}
+
+/*-----------------------------------------------------------------------------
+ * Pubsub commands implementation
+ *----------------------------------------------------------------------------*/
+
+void subscribeCommand(client *c) {
+    int j;
+
+    for (j = 1; j < c->argc; j++)
+        pubsubSubscribeChannel(c,c->argv[j]);
+    c->flags |= CLIENT_PUBSUB;
+}
+
+void unsubscribeCommand(client *c) {
+    if (c->argc == 1) {
+        pubsubUnsubscribeAllChannels(c,1);
+    } else {
+        int j;
+
+        for (j = 1; j < c->argc; j++)
+            pubsubUnsubscribeChannel(c,c->argv[j],1);
+    }
+    if (clientSubscriptionsCount(c) == 0) c->flags &= ~CLIENT_PUBSUB;
+}
+
+void psubscribeCommand(client *c) {
+    int j;
+
+    for (j = 1; j < c->argc; j++)
+        pubsubSubscribePattern(c,c->argv[j]);
+    c->flags |= CLIENT_PUBSUB;
+}
+
+void punsubscribeCommand(client *c) {
+    if (c->argc == 1) {
+        pubsubUnsubscribeAllPatterns(c,1);
+    } else {
+        int j;
+
+        for (j = 1; j < c->argc; j++)
+            pubsubUnsubscribePattern(c,c->argv[j],1);
+    }
+    if (clientSubscriptionsCount(c) == 0) c->flags &= ~CLIENT_PUBSUB;
+}
+
+void publishCommand(client *c) {
+    int receivers = pubsubPublishMessage(c->argv[1],c->argv[2]);
+    if (server.cluster_enabled)
+        clusterPropagatePublish(c->argv[1],c->argv[2]);
+    else
+        forceCommandPropagation(c,PROPAGATE_REPL);
+    addReplyLongLong(c,receivers);
+}
+
+/* PUBSUB command for Pub/Sub introspection. */
+void pubsubCommand(client *c) {
+    if (!strcasecmp(c->argv[1]->ptr,"channels") &&
+        (c->argc == 2 || c->argc ==3))
+    {
+        /* PUBSUB CHANNELS [<pattern>] */
+        sds pat = (c->argc == 2) ? NULL : c->argv[2]->ptr;
+        dictIterator *di = dictGetIterator(server.pubsub_channels);
+        dictEntry *de;
+        long mblen = 0;
+        void *replylen;
+
+        replylen = addDeferredMultiBulkLength(c);
+        while((de = dictNext(di)) != NULL) {
+            robj *cobj = dictGetKey(de);
+            sds channel = cobj->ptr;
+
+            if (!pat || stringmatchlen(pat, sdslen(pat),
+                                       channel, sdslen(channel),0))
+            {
+                addReplyBulk(c,cobj);
+                mblen++;
+            }
+        }
+        dictReleaseIterator(di);
+        setDeferredMultiBulkLength(c,replylen,mblen);
+    } else if (!strcasecmp(c->argv[1]->ptr,"numsub") && c->argc >= 2) {
+        /* PUBSUB NUMSUB [Channel_1 ... Channel_N] */
+        int j;
+
+        addReplyMultiBulkLen(c,(c->argc-2)*2);
+        for (j = 2; j < c->argc; j++) {
+            list *l = dictFetchValue(server.pubsub_channels,c->argv[j]);
+
+            addReplyBulk(c,c->argv[j]);
+            addReplyLongLong(c,l ? listLength(l) : 0);
+        }
+    } else if (!strcasecmp(c->argv[1]->ptr,"numpat") && c->argc == 2) {
+        /* PUBSUB NUMPAT */
+        addReplyLongLong(c,listLength(server.pubsub_patterns));
+    } else {
+        addReplyErrorFormat(c,
+            "Unknown PUBSUB subcommand or wrong number of arguments for '%s'",
+            (char*)c->argv[1]->ptr);
+    }
+}