MDEV-16689: core-file should become a real server variable

Mysql Bug#56124 bug analog fix using Sys_var_bit.

client/mysqlbinlog.cc

@@ -71,7 +71,7 @@ ulong bytes_sent = 0L, bytes_received = 0L;
 ulong mysqld_net_retry_count = 10L;
 ulong open_files_limit;
 ulong opt_binlog_rows_event_max_size;
-uint test_flags = 0; 
+ulonglong test_flags = 0;
 static uint opt_protocol= 0;
 static FILE *result_file;
 static char *result_file_name= 0;

mysql-test/suite/sys_vars/r/sysvars_server_embedded.result

@@ -471,6 +471,20 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	CORE_FILE
+SESSION_VALUE	NULL
+GLOBAL_VALUE	ON
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	NULL
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	BOOLEAN
+VARIABLE_COMMENT	write a core-file on crashes
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	OFF,ON
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	NULL
 VARIABLE_NAME	DATADIR
 SESSION_VALUE	NULL
 GLOBAL_VALUE	PATH

mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result

@@ -471,6 +471,20 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	CORE_FILE
+SESSION_VALUE	NULL
+GLOBAL_VALUE	ON
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	NULL
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	BOOLEAN
+VARIABLE_COMMENT	write a core-file on crashes
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	OFF,ON
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	NULL
 VARIABLE_NAME	DATADIR
 SESSION_VALUE	NULL
 GLOBAL_VALUE	PATH

sql/mysqld.cc

@@ -482,7 +482,7 @@ my_bool opt_master_verify_checksum= 0;
 my_bool opt_slave_sql_verify_checksum= 1;
 const char *binlog_format_names[]= {"MIXED", "STATEMENT", "ROW", NullS};
 volatile sig_atomic_t calling_initgroups= 0; /**< Used in SIGSEGV handler. */
-uint mysqld_port, test_flags, select_errors, dropping_tables, ha_open_options;
+uint mysqld_port, select_errors, dropping_tables, ha_open_options;
 uint mysqld_extra_port;
 uint mysqld_port_timeout;
 ulong delay_key_write_options;
@@ -509,6 +509,7 @@ ulonglong max_binlog_cache_size=0;
 ulong slave_max_allowed_packet= 0;
 ulonglong binlog_stmt_cache_size=0;
 ulonglong  max_binlog_stmt_cache_size=0;
+ulonglong test_flags;
 ulonglong query_cache_size=0;
 ulong query_cache_limit=0;
 ulong executed_events=0;

sql/mysqld.h

@@ -159,7 +159,8 @@ extern ulong opt_tc_log_size, tc_log_max_pages_used, tc_log_page_size;
 extern ulong tc_log_page_waits;
 extern my_bool relay_log_purge, opt_innodb_safe_binlog, opt_innodb;
 extern my_bool relay_log_recovery;
-extern uint test_flags,select_errors,ha_open_options;
+extern uint select_errors,ha_open_options;
+extern ulonglong test_flags;
 extern uint protocol_version, mysqld_port, dropping_tables;
 extern ulong delay_key_write_options;
 extern char *opt_logname, *opt_slow_logname, *opt_bin_logname, 

sql/sys_vars.cc

@@ -440,6 +440,12 @@ bool check_has_super(sys_var *self, THD *thd, set_var *var)
 #endif
   return false;
 }
+
+static Sys_var_bit Sys_core_file("core_file", "write a core-file on crashes",
+          READ_ONLY GLOBAL_VAR(test_flags), NO_CMD_LINE,
+          TEST_CORE_ON_SIGNAL, DEFAULT(FALSE), NO_MUTEX_GUARD, NOT_IN_BINLOG,
+          0,0,0);
+
 static bool binlog_format_check(sys_var *self, THD *thd, set_var *var)
 {
   if (check_has_super(self, thd, var))