MDEV-30188: Ensure all binlog* variables are visible as system variables

Turn the remaining three `binlog*` options binlog_do_db, binlog_ignore_db,
binlog_rows_event_max_size into global variables so that they can be
visible from the SQL user level. This is for audit / secure
configuration check purposes.

Create new MTR tests to make sure that the newly created global
variables can be visible from the command line interface.

Behavior before the code change:

    MariaDB [(none)]> SHOW GLOBAL VARIABLES WHERE
        -> Variable_name LIKE 'binlog_do_db' OR
        -> Variable_name LIKE 'binlog_ignore_db' OR
        -> Variable_name LIKE 'binlog_row_event_max_size';
    Empty set (0.001 sec)

Behavior after the code change:

    MariaDB [(none)]> SHOW GLOBAL VARIABLES WHERE
        -> Variable_name LIKE 'binlog_do_db' OR
        -> Variable_name LIKE 'binlog_ignore_db' OR
        -> Variable_name LIKE 'binlog_row_event_max_size';
    +---------------------------+-------+
    | Variable_name             | Value |
    +---------------------------+-------+
    | binlog_do_db              |       |
    | binlog_ignore_db          |       |
    | binlog_row_event_max_size | 8192  |
    +---------------------------+-------+
    3 rows in set (0.001 sec)

Note:

For `binlog_do_db` and `binlog_ignore_db`, we add a new class
`Sys_var_binlog_filter` to handle the dynamically-composable command line
options for `binlog_do_db` and `binlog_ignore_db`. Below
is the motivation:

When the users start the server with the option
    --binlog-do-db="database1" --binlog-do-db="database2"
The expected behavior is that the system should allow replication for
both `database1` and `database2`, which is the logic of the original
code.

However, when turning the variables into system variables, the
functionality does not exist any more, since system variables will only
handle the last occurrence of the option, and in this case, the system
will only be able to handle `database2`.

Copyright:

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the BSD-new
license. I am contributing on behalf of my employer Amazon Web Services, Inc.

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

+#
+# MDEV-30188 Show "--binlog_do_db" state in SYSTEM VARIABLES
+#
+SELECT @@binlog_do_db AS EXPECT_NULL;
+EXPECT_NULL
+
+SET @@GLOBAL.binlog_do_db='database1';
+ERROR HY000: Variable 'binlog_do_db' is a read only variable
+# restart: --binlog_do_db=database1 --binlog_do_db=database2
+SELECT @@binlog_do_db AS EXPECT_database1_database2;
+EXPECT_database1_database2
+database1,database2

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

+#
+# MDEV-30188 Show "--binlog_ignore_db" state in SYSTEM VARIABLES
+#
+SELECT @@binlog_ignore_db AS EXPECT_NULL;
+EXPECT_NULL
+
+SET @@GLOBAL.binlog_ignore_db='database1';
+ERROR HY000: Variable 'binlog_ignore_db' is a read only variable
+# restart: --binlog_ignore_db=database1 --binlog_ignore_db=database2
+SELECT @@binlog_ignore_db AS EXPECT_database1_database2;
+EXPECT_database1_database2
+database1,database2

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

+#
+# MDEV-30188 Show "--binlog_row_event_max_size" state in SYSTEM VARIABLES
+#
+SELECT @@binlog_row_event_max_size AS EXPECT_8192;
+EXPECT_8192
+8192
+SET @@GLOBAL.binlog_row_event_max_size=128;
+ERROR HY000: Variable 'binlog_row_event_max_size' is a read only variable
+# restart: --binlog_row_event_max_size=4096
+SELECT @@binlog_row_event_max_size AS EXPECT_4096;
+EXPECT_4096
+4096

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

@@ -412,6 +412,16 @@ NUMERIC_BLOCK_SIZE	NULL
 ENUM_VALUE_LIST	OFF,ON
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	OPTIONAL
+VARIABLE_NAME	BINLOG_DO_DB
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	VARCHAR
+VARIABLE_COMMENT	Tells the primary it should log updates for the specified database, and exclude all others not explicitly mentioned.
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	NULL
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	NULL
 VARIABLE_NAME	BINLOG_EXPIRE_LOGS_SECONDS
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BIGINT UNSIGNED
@@ -442,6 +452,16 @@ NUMERIC_BLOCK_SIZE	NULL
 ENUM_VALUE_LIST	MIXED,STATEMENT,ROW
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	BINLOG_IGNORE_DB
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	VARCHAR
+VARIABLE_COMMENT	Tells the primary that updates to the given database should not be logged to the binary log.
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	NULL
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	NULL
 VARIABLE_NAME	BINLOG_OPTIMIZE_THREAD_SCHEDULING
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BOOLEAN
@@ -452,6 +472,16 @@ NUMERIC_BLOCK_SIZE	NULL
 ENUM_VALUE_LIST	OFF,ON
 READ_ONLY	YES
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	BINLOG_ROW_EVENT_MAX_SIZE
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	BIGINT UNSIGNED
+VARIABLE_COMMENT	The maximum size of a row-based binary log event in bytes. Rows will be grouped into events smaller than this size if possible. The value has to be a multiple of 256.
+NUMERIC_MIN_VALUE	256
+NUMERIC_MAX_VALUE	4294967040
+NUMERIC_BLOCK_SIZE	256
+ENUM_VALUE_LIST	NULL
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	REQUIRED
 VARIABLE_NAME	BINLOG_ROW_IMAGE
 VARIABLE_SCOPE	SESSION
 VARIABLE_TYPE	ENUM

mysql-test/suite/sys_vars/t/binlog_do_db.test

+--echo #
+--echo # MDEV-30188 Show "--binlog_do_db" state in SYSTEM VARIABLES
+--echo #
+
+# Confirm that "--binlog_do_db" option has the default value.
+SELECT @@binlog_do_db AS EXPECT_NULL;
+
+# `READ ONLY` variables must not be able to be reset.
+--Error ER_INCORRECT_GLOBAL_LOCAL_VAR (1238): Variable 'binlog_do_db' is a read only variable
+SET @@GLOBAL.binlog_do_db='database1';
+
+# Restart the server with "--binlog_do_db='database1' --binlog_do_db='database2'" option
+--let $restart_parameters = "--binlog_do_db='database1' --binlog_do_db='database2'"
+--source include/restart_mysqld.inc
+SELECT @@binlog_do_db AS EXPECT_database1_database2;
+

mysql-test/suite/sys_vars/t/binlog_ignore_db.test

+--echo #
+--echo # MDEV-30188 Show "--binlog_ignore_db" state in SYSTEM VARIABLES
+--echo #
+
+# Confirm that "--binlog_ignore_db" option has the default value.
+SELECT @@binlog_ignore_db AS EXPECT_NULL;
+
+# `READ ONLY` variables must not be able to be reset.
+--Error ER_INCORRECT_GLOBAL_LOCAL_VAR (1238): Variable 'binlog_ignore_db' is a read only variable
+SET @@GLOBAL.binlog_ignore_db='database1';
+
+# Restart the server with "--binlog_ignore_db='database1' --binlog_ignore_db='database2'" option
+--let $restart_parameters = "--binlog_ignore_db='database1' --binlog_ignore_db='database2'"
+--source include/restart_mysqld.inc
+SELECT @@binlog_ignore_db AS EXPECT_database1_database2;
+

mysql-test/suite/sys_vars/t/binlog_row_event_max_size.test

+--echo #
+--echo # MDEV-30188 Show "--binlog_row_event_max_size" state in SYSTEM VARIABLES
+--echo #
+
+SELECT @@binlog_row_event_max_size AS EXPECT_8192;
+
+# `READ ONLY` variables must not be able to be reset.
+--Error ER_INCORRECT_GLOBAL_LOCAL_VAR (1238): Variable 'binlog_row_event_max_size' is a read only variable
+SET @@GLOBAL.binlog_row_event_max_size=128;
+
+# Restart the server the server with "--binlog_row_event_max_size=4096" option
+--let $restart_parameters = "--binlog_row_event_max_size=4096"
+--source include/restart_mysqld.inc
+SELECT @@binlog_row_event_max_size AS EXPECT_4096;
+
+

sql/mysqld.cc

@@ -6491,16 +6491,6 @@ struct my_option my_long_options[]=
   {"binlog-ignore-db", OPT_BINLOG_IGNORE_DB,
    "Tells the master that updates to the given database should not be logged to the binary log.",
    0, 0, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
-  {"binlog-row-event-max-size", 0,
-   "The maximum size of a row-based binary log event in bytes. Rows will be "
-   "grouped into events smaller than this size if possible. "
-   "The value has to be a multiple of 256.",
-   &opt_binlog_rows_event_max_size, &opt_binlog_rows_event_max_size,
-   0, GET_ULONG, REQUIRED_ARG,
-   /* def_value */ 8192, /* min_value */  256, /* max_value */ UINT_MAX32-1,
-   /* sub_size */     0, /* block_size */ 256,
-   /* app_type */ 0
-  },
 #ifndef DISABLE_GRANT_OPTIONS
   {"bootstrap", OPT_BOOTSTRAP, "Used by mysql installation scripts.", 0, 0, 0,
    GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},

sql/privilege.h

@@ -469,6 +469,9 @@ constexpr privilege_t PRIV_STMT_PURGE_BINLOG= BINLOG_ADMIN_ACL;
 // Was REPL_SLAVE_ACL prior to 10.5.2
 constexpr privilege_t PRIV_STMT_SHOW_BINLOG_EVENTS= BINLOG_MONITOR_ACL;
 
+constexpr privilege_t PRIV_SET_SYSTEM_GLOBAL_VAR_BINLOG_DO_DB = BINLOG_ADMIN_ACL | SUPER_ACL;
+
+constexpr privilege_t PRIV_SET_SYSTEM_GLOBAL_VAR_BINLOG_IGNORE_DB = BINLOG_ADMIN_ACL | SUPER_ACL;
 
 /*
   Privileges for replication related statements and commands

sql/sys_vars.cc

@@ -41,6 +41,7 @@
 #include <thr_alarm.h>
 #include "slave.h"
 #include "rpl_mi.h"
+#include "rpl_filter.h"
 #include "transaction.h"
 #include "mysqld.h"
 #include "lock.h"
@@ -3140,7 +3141,6 @@ static Sys_var_ulong Sys_query_prealloc_size(
        BLOCK_SIZE(1024), NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
        ON_UPDATE(fix_thd_mem_root));
 
-
 // this has to be NO_CMD_LINE as the command-line option has a different name
 static Sys_var_mybool Sys_skip_external_locking(
        "skip_external_locking", "Don't use system (external) locking",
@@ -5597,6 +5597,30 @@ Sys_var_rpl_filter::global_value_ptr(THD *thd,
   return ret;
 }
 
+const uchar *
+Sys_var_binlog_filter::global_value_ptr(THD *thd,
+                                        const LEX_CSTRING *base_name) const
+{
+  char buf[256];
+  String tmp(buf, sizeof(buf), &my_charset_bin);
+  uchar *ret;
+
+  tmp.length(0);
+
+  switch (opt_id) {
+  case OPT_BINLOG_DO_DB:
+    binlog_filter->get_do_db(&tmp);
+    break;
+  case OPT_BINLOG_IGNORE_DB:
+    binlog_filter->get_ignore_db(&tmp);
+    break;
+  }
+
+  ret= (uchar *) thd->strmake(tmp.ptr(), tmp.length());
+
+  return ret;
+}
+
 static Sys_var_rpl_filter Sys_replicate_do_db(
        "replicate_do_db", OPT_REPLICATE_DO_DB,
        "Tell the slave to restrict replication to updates of tables "
@@ -5607,6 +5631,12 @@ static Sys_var_rpl_filter Sys_replicate_do_db(
        "actual names of table(s) being updated are checked.",
        PRIV_SET_SYSTEM_GLOBAL_VAR_REPLICATE_DO_DB);
 
+static Sys_var_binlog_filter Sys_binlog_do_db(
+      "binlog_do_db", OPT_BINLOG_DO_DB,
+      "Tells the primary it should log updates for the specified database, "
+      "and exclude all others not explicitly mentioned.",
+      PRIV_SET_SYSTEM_GLOBAL_VAR_BINLOG_DO_DB);
+
 static Sys_var_rpl_filter Sys_replicate_rewrite_db(
        "replicate_rewrite_db", OPT_REPLICATE_REWRITE_DB,
        "Tells the slave to replicate binlog events "
@@ -5630,6 +5660,11 @@ static Sys_var_rpl_filter Sys_replicate_ignore_db(
        "actual names of table(s) being updated are checked.",
        PRIV_SET_SYSTEM_GLOBAL_VAR_REPLICATE_IGNORE_DB);
 
+static Sys_var_binlog_filter Sys_binlog_ignore_db(
+      "binlog_ignore_db", OPT_BINLOG_IGNORE_DB,
+      "Tells the primary that updates to the given database should not be logged to the binary log.",
+      PRIV_SET_SYSTEM_GLOBAL_VAR_BINLOG_IGNORE_DB);
+
 static Sys_var_rpl_filter Sys_replicate_ignore_table(
        "replicate_ignore_table", OPT_REPLICATE_IGNORE_TABLE,
        "Tells the slave thread not to replicate any statement that "
@@ -5656,6 +5691,15 @@ static Sys_var_charptr_fscs Sys_slave_load_tmpdir(
        READ_ONLY GLOBAL_VAR(slave_load_tmpdir), CMD_LINE(REQUIRED_ARG),
        DEFAULT(0));
 
+static Sys_var_ulong Sys_opt_binlog_rows_event_max_size(
+      "binlog_row_event_max_size",
+      "The maximum size of a row-based binary log event in bytes. Rows will be "
+      "grouped into events smaller than this size if possible. "
+      "The value has to be a multiple of 256.",
+      READ_ONLY GLOBAL_VAR(opt_binlog_rows_event_max_size), CMD_LINE(REQUIRED_ARG),
+      VALID_RANGE(256, UINT_MAX32 - (UINT_MAX32 % 256)), DEFAULT(8192),
+      BLOCK_SIZE(256));
+
 static Sys_var_on_access_global<Sys_var_uint,
                                 PRIV_SET_SYSTEM_GLOBAL_VAR_SLAVE_NET_TIMEOUT>
 Sys_slave_net_timeout(

sql/sys_vars.inl

@@ -797,6 +797,56 @@ class Sys_var_rpl_filter: public sys_var
   bool set_filter_value(const char *value, Master_info *mi);
 };
 
+class Sys_var_binlog_filter: public sys_var
+{
+private:
+  int opt_id;
+  privilege_t m_access_global;
+
+public:
+  Sys_var_binlog_filter(const char *name, int getopt_id, const char *comment,
+                     privilege_t access_global)
+    : sys_var(&all_sys_vars, name, comment, sys_var::READONLY+sys_var::GLOBAL, 0, NO_GETOPT,
+              NO_ARG, SHOW_CHAR, 0, NULL, VARIABLE_NOT_IN_BINLOG,
+              NULL, NULL, NULL), opt_id(getopt_id),
+      m_access_global(access_global)
+  {
+    option.var_type|= GET_STR;
+  }
+
+  bool do_check(THD *thd, set_var *var) override
+  {
+    DBUG_ASSERT(FALSE);
+    return true;
+  }
+  void session_save_default(THD *, set_var *) override
+  { DBUG_ASSERT(FALSE); }
+
+  void global_save_default(THD *thd, set_var *var) override
+  { DBUG_ASSERT(FALSE); }
+
+  bool session_update(THD *, set_var *) override
+  {
+    DBUG_ASSERT(FALSE);
+    return true;
+  }
+
+  bool global_update(THD *thd, set_var *var) override
+  {
+    DBUG_ASSERT(FALSE);
+    return true;
+  }
+
+  bool on_check_access_global(THD *thd) const override
+  {
+    return check_global_access(thd, m_access_global);
+  }
+
+  protected:
+  const uchar *global_value_ptr(THD *thd, const LEX_CSTRING *base)
+    const override;
+};
+
 /**
   The class for string variables. Useful for strings that aren't necessarily
   \0-terminated. Otherwise the same as Sys_var_charptr.