BUG#34141: mysqlbinlog cannot read 4.1 binlogs containing load data infile

Main problem: mysql 5.1 cannot read binlogs from 4.1.
Subproblem 1: There is a mistake in sql_ex_info::init. The read_str()
function updates its first argument to point to the next character to
read. However, it is applied only to a copy of the buffer pointer, so the
real buffer pointer is not updated.
Fix 1: do not take a copy of the buffer pointer. The copy was needed
because sql_ex_info::init does not use the const attribute on some of its
arguments. So we add the const attribute, too.
Subproblem 2: The first BINLOG statement is asserted to be a
FORMAT_DESCRIPTION_LOG_EVENT, but 4.1 binlogs begin with START_EVENT_V3.
Fix 2: allow START_EVENT_V3 too.


mysql-test/suite/binlog/std_data/binlog_old_version_4_1.000001:
  New BitKeeper file ``mysql-test/suite/binlog/std_data/binlog_old_version_4_1.000001''
mysql-test/suite/binlog/r/binlog_old_versions.result:
  Updated result file.
mysql-test/suite/binlog/t/binlog_old_versions.test:
  Added a test reading an old 4.1 binlog.
sql/log_event.cc:
  1. Added const keyword at the following places:
   - input buffer for pretty_print_str
   - input buffer for write_str
   - input buffer, end pointer, and return value from sql_ex_info::init
  2. Fixed the bug by not taking a copy of buf before calling read_str in
  sql_ex_info::init().
sql/log_event.h:
  Added const keyword to fields of the sql_ex_info struct.
  Added const keyword to arguments and return value of sql_ex_info::init
sql/sql_binlog.cc:
  The first BINLOG statement must describe the format for future BINLOG
  statements. Otherwise, we do not know how to read the BINLOG statement.
  Problem: only FORMAT_DESCRIPTION_EVENT is currently allowed as the first
  event. Binlogs from 4.1 begin with a START_EVENT_V3, which serves the
  same purpose.
  Fix: We now allow the first BINLOG statement to be a START_EVENT_V3, as
  well as a FORMAT_DESCRIPTION_EVENT.

1 files changed, 6 insertions, 6 deletions

diff --git a/sql/log_event.h b/sql/log_event.h
index 31c1ab7173a..c85d620d831 100644
--- a/sql/log_event.h
+++ b/sql/log_event.h
@@ -152,11 +152,11 @@ struct old_sql_ex
 struct sql_ex_info
 {
   sql_ex_info() {}                            /* Remove gcc warning */
-  char* field_term;
-  char* enclosed;
-  char* line_term;
-  char* line_start;
-  char* escaped;
+  const char* field_term;
+  const char* enclosed;
+  const char* line_term;
+  const char* line_start;
+  const char* escaped;
   int cached_new_format;
   uint8 field_term_len,enclosed_len,line_term_len,line_start_len, escaped_len;
   char opt_flags;
@@ -171,7 +171,7 @@ struct sql_ex_info
 	    line_start_len + escaped_len + 6 : 7);
   }
   bool write_data(IO_CACHE* file);
-  char* init(char* buf,char* buf_end,bool use_new_format);
+  const char* init(const char* buf, const char* buf_end, bool use_new_format);
   bool new_format()
   {
     return ((cached_new_format != -1) ? cached_new_format :