From abddf0b0af6c20ca89e9085c1dc3bea9d2ac580f Mon Sep 17 00:00:00 2001
From: Georg Richter <georg@mariadb.com>
Date: Wed, 22 Jun 2022 16:25:37 +0200
Subject: [PATCH] Fixed ROTATE_EVENT

If timestamp is zero and flag LOG_EVEBNT_ARTIFICIAL_F was set the
event is a fake ROTATE_EVENT (https://mariadb.com/kb/en/fake-rotate_event/)
and needs different handling:
- a checksum might follow if @@binlog_checksum was set (CRC32)
- length calculation is different
---
 include/mariadb_rpl.h    |  1 +
 libmariadb/mariadb_rpl.c | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/include/mariadb_rpl.h b/include/mariadb_rpl.h
index 0f7b948e..f3e39894 100644
--- a/include/mariadb_rpl.h
+++ b/include/mariadb_rpl.h
@@ -155,6 +155,7 @@ typedef struct st_mariadb_rpl {
   uint32_t flags;
   uint8_t fd_header_len; /* header len from last format description event */
   uint8_t use_checksum;
+  uint8_t artificial_checksun;
 } MARIADB_RPL;
 
 /* Event header */
diff --git a/libmariadb/mariadb_rpl.c b/libmariadb/mariadb_rpl.c
index 23ca4635..679db345 100644
--- a/libmariadb/mariadb_rpl.c
+++ b/libmariadb/mariadb_rpl.c
@@ -67,6 +67,21 @@ MARIADB_RPL * STDCALL mariadb_rpl_init_ex(MYSQL *mysql, unsigned int version)
   }
   rpl->version= version;
   rpl->mysql= mysql;
+
+  if (!mysql_query(mysql, "select @@binlog_checksum"))
+  {
+    MYSQL_RES *result;
+    if ((result= mysql_store_result(mysql)))
+    {
+      MYSQL_ROW row= mysql_fetch_row(result);
+      if (!strcmp(row[0], "CRC32"))
+      {
+        rpl->artificial_checksun= 1;
+      }
+      mysql_free_result(result);
+    }
+  }
+
   return rpl;
 }
 
@@ -378,8 +393,23 @@ MARIADB_RPL_EVENT * STDCALL mariadb_rpl_fetch(MARIADB_RPL *rpl, MARIADB_RPL_EVEN
       break;
     case ROTATE_EVENT:
       rpl_event->event.rotate.position= uint8korr(ev);
-      len= rpl_event->event_length - (ev - rpl->mysql->net.read_pos) - 8;
       ev+= 8;
+      if (rpl_event->timestamp == 0 &&
+          rpl_event->flags & LOG_EVENT_ARTIFICIAL_F)
+      {
+        const uint8_t header_size= 19;
+        len= rpl_event->event_length - header_size - 8;
+        if (rpl->artificial_checksun)
+        {
+          len-= 4;
+          int4store(ev + len, rpl_event->checksum);
+          rpl->artificial_checksun= 0;
+        }
+      }
+      else
+      {
+        len= rpl_event->event_length - (ev - rpl->mysql->net.read_pos) - 1;
+      }
       if (rpl_alloc_string(rpl_event, &rpl_event->event.rotate.filename, ev, len) ||
           ma_set_rpl_filename(rpl, ev, len))
         goto mem_error;