From 1824e3a3a37eb9618aa487e6e071395758bdaca8 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Fri, 30 Dec 2011 19:34:40 +0100
Subject: [PATCH] Fixed replication when multiple slaves are attaching at the
 same time. The output buffer was not copied correctly between slaves. This
 fixes issue #141.

---
 src/networking.c  | 10 ++++++++++
 src/redis.h       |  1 +
 src/replication.c |  3 +--
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/networking.c b/src/networking.c
index 59512f0f..df059f6b 100644
--- a/src/networking.c
+++ b/src/networking.c
@@ -401,6 +401,16 @@ void addReplyBulkLongLong(redisClient *c, long long ll) {
     addReplyBulkCBuffer(c,buf,len);
 }
 
+/* Copy 'src' client output buffers into 'dst' client output buffers.
+ * The function takes care of freeing the old output buffers of the
+ * destination client. */
+void copyClientOutputBuffer(redisClient *dst, redisClient *src) {
+    listRelease(dst->reply);
+    dst->reply = listDup(src->reply);
+    memcpy(dst->buf,src->buf,src->bufpos);
+    dst->bufpos = src->bufpos;
+}
+
 static void acceptCommonHandler(int fd) {
     redisClient *c;
     if ((c = createClient(fd)) == NULL) {
diff --git a/src/redis.h b/src/redis.h
index aa79b4ad..95e1127b 100644
--- a/src/redis.h
+++ b/src/redis.h
@@ -774,6 +774,7 @@ void addReplyStatus(redisClient *c, char *status);
 void addReplyDouble(redisClient *c, double d);
 void addReplyLongLong(redisClient *c, long long ll);
 void addReplyMultiBulkLen(redisClient *c, long length);
+void copyClientOutputBuffer(redisClient *dst, redisClient *src);
 void *dupClientReplyValue(void *o);
 void getClientsMaxBuffers(unsigned long *longest_output_list,
                           unsigned long *biggest_input_buffer);
diff --git a/src/replication.c b/src/replication.c
index e08517e8..479dcf43 100644
--- a/src/replication.c
+++ b/src/replication.c
@@ -122,8 +122,7 @@ void syncCommand(redisClient *c) {
         if (ln) {
             /* Perfect, the server is already registering differences for
              * another slave. Set the right state, and copy the buffer. */
-            listRelease(c->reply);
-            c->reply = listDup(slave->reply);
+            copyClientOutputBuffer(c,slave);
             c->replstate = REDIS_REPL_WAIT_BGSAVE_END;
             redisLog(REDIS_NOTICE,"Waiting for end of BGSAVE for SYNC");
         } else {
-- 
2.45.2