Bug#18742916 MYSQLBINLOG --RAW DOES NOT CHECK FOR ERRORS

Venkatesh Duggirala · Venkatesh Duggirala · commit 5138672d7084 · 2014-06-11T16:18:57.000+05:30
Problem: mysqlbinlog --raw does not check for fail write errors

Analysis: We have two my_fwrite calls in mysqlbinlog.cc file
which does not check for failures. If my_fwrite returns error and
if we are not catching the error we could end up in corrupting
written out binary logs without reporting any errors/warnings.

Fix: catch my_fwrite return values in those two places
and throw error if fails.
diff --git a/client/mysqlbinlog.cc b/client/mysqlbinlog.cc
@@ -2320,8 +2320,14 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
             error("Could not create log file '%s'", log_file_name);
             DBUG_RETURN(ERROR_STOP);
           }
-          my_fwrite(result_file, (const uchar*) BINLOG_MAGIC,
-                    BIN_LOG_HEADER_SIZE, MYF(0));
+          DBUG_EXECUTE_IF("simulate_result_file_write_error_for_FD_event",
+                          DBUG_SET("+d,simulate_fwrite_error"););
+          if (my_fwrite(result_file, (const uchar*) BINLOG_MAGIC,
+                        BIN_LOG_HEADER_SIZE, MYF(MY_NABP)))
+          {
+            error("Could not write into log file '%s'", log_file_name);
+            DBUG_RETURN(ERROR_STOP);
+          }
           /*
             Need to handle these events correctly in raw mode too 
             or this could get messy
@@ -2344,7 +2350,13 @@ static Exit_status dump_remote_log_entries(PRINT_EVENT_INFO *print_event_info,
 
       if (raw_mode)
       {
-        my_fwrite(result_file, net->read_pos + 1 , len - 1, MYF(0));
+        DBUG_EXECUTE_IF("simulate_result_file_write_error",
+                        DBUG_SET("+d,simulate_fwrite_error"););
+        if (my_fwrite(result_file, net->read_pos + 1 , len - 1, MYF(MY_NABP)))
+        {
+          error("Could not write into log file '%s'", log_file_name);
+          retval= ERROR_STOP;
+        }
         if (ev)
         {
           ev->temp_buf=0;
diff --git a/mysql-test/r/mysqlbinlog.result b/mysql-test/r/mysqlbinlog.result
@@ -969,5 +969,10 @@ DELIMITER ;
 ROLLBACK /* added by mysqlbinlog */;
 /*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
 /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
+#
+# Bug#18742916 : MYSQLBINLOG --RAW DOES NOT CHECK FOR ERRORS
+#
+ERROR: Could not write into log file 'MYSQLTEST_VARDIR/tmp/master-bin.000001'
+ERROR: Could not write into log file 'MYSQLTEST_VARDIR/tmp/master-bin.000001'
 
 End of tests
diff --git a/mysql-test/t/mysqlbinlog.test b/mysql-test/t/mysqlbinlog.test
@@ -563,5 +563,19 @@ eval SET GLOBAL SERVER_ID = $old_server_id;
 
 --exec $MYSQL_BINLOG -uroot --password="" std_data/master-bin.000001 2>&1
 
+--echo #
+--echo # Bug#18742916 : MYSQLBINLOG --RAW DOES NOT CHECK FOR ERRORS
+--echo #
+
+--replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+--error 1
+--exec $MYSQL_BINLOG -#d,simulate_result_file_write_error_for_FD_event --raw --read-from-remote-server --user=root --host=127.0.0.1 --port=$MASTER_MYPORT -r$MYSQLTEST_VARDIR/tmp/ master-bin.000001 2>&1
+
+--replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+--error 1
+--exec $MYSQL_BINLOG -#d,simulate_result_file_write_error --raw --read-from-remote-server --user=root --host=127.0.0.1 --port=$MASTER_MYPORT -r$MYSQLTEST_VARDIR/tmp/ master-bin.000001 2>&1
+# Cleanup
+--remove_file $MYSQLTEST_VARDIR/tmp/master-bin.000001
+
 --echo
 --echo End of tests
diff --git a/mysys/my_fstream.c b/mysys/my_fstream.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
+/* Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -104,6 +104,7 @@ size_t my_fwrite(FILE *stream, const uchar *Buffer, size_t Count, myf MyFlags)
   DBUG_ENTER("my_fwrite");
   DBUG_PRINT("my",("stream: 0x%lx  Buffer: 0x%lx  Count: %u  MyFlags: %d",
 		   (long) stream, (long) Buffer, (uint) Count, MyFlags));
+  DBUG_EXECUTE_IF("simulate_fwrite_error",  DBUG_RETURN(-1););
 
 #if !defined(NO_BACKGROUND) && defined(USE_MY_STREAM)
   errors=0;
