Merge MWL#180 into main MariaDB 5.3.

1 files changed, 61 insertions, 0 deletions

diff --git a/sql/rpl_utility.cc b/sql/rpl_utility.cc
index 6058c473e9f..d4616723117 100644
--- a/sql/rpl_utility.cc
+++ b/sql/rpl_utility.cc
@@ -14,6 +14,8 @@
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */
 
 #include "rpl_utility.h"
+
+#ifndef MYSQL_CLIENT
 #include "rpl_rli.h"
 
 /*********************************************************************
@@ -224,3 +226,62 @@ table_def::compatible_with(Relay_log_info const *rli_arg, TABLE *table)
 
   return error;
 }
+
+#endif /* MYSQL_CLIENT */
+
+
+/**
+   @param   even_buf    point to the buffer containing serialized event
+   @param   event_len   length of the event accounting possible checksum alg
+
+   @return  TRUE        if test fails
+            FALSE       as success
+*/
+bool event_checksum_test(uchar *event_buf, ulong event_len, uint8 alg)
+{
+  bool res= FALSE;
+  uint16 flags= 0; // to store in FD's buffer flags orig value
+
+  if (alg != BINLOG_CHECKSUM_ALG_OFF && alg != BINLOG_CHECKSUM_ALG_UNDEF)
+  {
+    ha_checksum incoming;
+    ha_checksum computed;
+
+    if (event_buf[EVENT_TYPE_OFFSET] == FORMAT_DESCRIPTION_EVENT)
+    {
+#ifndef DBUG_OFF
+      int8 fd_alg= event_buf[event_len - BINLOG_CHECKSUM_LEN - 
+                             BINLOG_CHECKSUM_ALG_DESC_LEN];
+#endif
+      /*
+        FD event is checksummed and therefore verified w/o the binlog-in-use flag
+      */
+      flags= uint2korr(event_buf + FLAGS_OFFSET);
+      if (flags & LOG_EVENT_BINLOG_IN_USE_F)
+        event_buf[FLAGS_OFFSET] &= ~LOG_EVENT_BINLOG_IN_USE_F;
+      /* 
+         The only algorithm currently is CRC32. Zero indicates 
+         the binlog file is checksum-free *except* the FD-event.
+      */
+      DBUG_ASSERT(fd_alg == BINLOG_CHECKSUM_ALG_CRC32 || fd_alg == 0);
+      DBUG_ASSERT(alg == BINLOG_CHECKSUM_ALG_CRC32);
+      /*
+        Complile time guard to watch over  the max number of alg
+      */
+      compile_time_assert(BINLOG_CHECKSUM_ALG_ENUM_END <= 0x80);
+    }
+    incoming= uint4korr(event_buf + event_len - BINLOG_CHECKSUM_LEN);
+    computed= my_checksum(0L, NULL, 0);
+    /* checksum the event content but the checksum part itself */
+    computed= my_checksum(computed, (const uchar*) event_buf, 
+                          event_len - BINLOG_CHECKSUM_LEN);
+    if (flags != 0)
+    {
+      /* restoring the orig value of flags of FD */
+      DBUG_ASSERT(event_buf[EVENT_TYPE_OFFSET] == FORMAT_DESCRIPTION_EVENT);
+      event_buf[FLAGS_OFFSET]= flags;
+    }
+    res= !(computed == incoming);
+  }
+  return DBUG_EVALUATE_IF("simulate_checksum_test_failure", TRUE, res);
+}