MDEV-495 backport --ignore-db-dir.

The feature was backported from MySQL 5.6.
Some code was added to make commands as
        SELECT * FROM ignored_db.t1;
        CALL ignored_db.proc();
        USE ignored_db;
to take that option into account.

per-file comments:
  mysql-test/r/ignore_db_dirs_basic.result
        test result added.
  mysql-test/t/ignore_db_dirs_basic-master.opt
        options for the test,
        actually the set of --ignore-db-dir lines.
  mysql-test/t/ignore_db_dirs_basic.test
        test for the feature.
        Same test from 5.6 was taken as a basis,
        then tests for SELECT, CALL etc were added.

per-file comments:
  sql/mysql_priv.h
MDEV-495 backport --ignore-db-dir.
        interface for db_name_is_in_ignore_list() added.
  sql/mysqld.cc
MDEV-495 backport --ignore-db-dir.
        --ignore-db-dir handling.
  sql/set_var.cc
MDEV-495 backport --ignore-db-dir.
        the @@ignore_db_dirs variable added.
  sql/sql_show.cc
MDEV-495 backport --ignore-db-dir.
        check if the directory is ignored.
  sql/sql_show.h
MDEV-495 backport --ignore-db-dir.
        interface added for opt_ignored_db_dirs.
  sql/table.cc
MDEV-495 backport --ignore-db-dir.
        check if the directory is ignored.

3 files changed, 96 insertions, 0 deletions

diff --git a/mysql-test/r/ignore_db_dirs_basic.result b/mysql-test/r/ignore_db_dirs_basic.result
new file mode 100644
index 00000000000..a0bbcb54f15
--- /dev/null
+++ b/mysql-test/r/ignore_db_dirs_basic.result
@@ -0,0 +1,47 @@
+select @@ignore_db_dirs;
+@@ignore_db_dirs
+e,lost+found,.mysqlgui,ignored_db
+# Check that SHOW DATABASES ignores all directories from
+# @@ignore_db_dirs and all directories with names starting
+# with '.'
+SHOW DATABASES;
+Database
+information_schema
+#mysql50#.otherdir
+mtr
+mysql
+test
+USE ignored_db;
+ERROR 42000: Incorrect database name 'ignored_db'
+SELECT * FROM ignored_db.t1;
+ERROR 42000: Incorrect database name 'ignored_db'
+CALL ignored_db.p1();
+ERROR 42000: Incorrect database name 'ignored_db'
+SELECT COUNT(*) FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME='ignored_db';
+COUNT(*)
+1
+CREATE DATABASE ignored_db;
+ERROR 42000: Incorrect database name 'ignored_db'
+CREATE DATABASE `lost+found`;
+USE `lost+found`;
+CREATE TABLE t1(id INT);
+INSERT INTO t1 VALUES (1), (2);
+SELECT * FROM `lost+found`.t1;
+id
+1
+2
+SHOW DATABASES;
+Database
+information_schema
+#mysql50#.otherdir
+lost+found
+mtr
+mysql
+test
+DROP DATABASE `lost+found`;
+SET @@global.ignore_db_dirs = 'aha';
+ERROR HY000: Variable 'ignore_db_dirs' is a read only variable
+SET @@local.ignore_db_dirs = 'aha';
+ERROR HY000: Variable 'ignore_db_dirs' is a read only variable
+SET @@ignore_db_dirs = 'aha';
+ERROR HY000: Variable 'ignore_db_dirs' is a read only variable
diff --git a/mysql-test/t/ignore_db_dirs_basic-master.opt b/mysql-test/t/ignore_db_dirs_basic-master.opt
new file mode 100644
index 00000000000..30ee4f67284
--- /dev/null
+++ b/mysql-test/t/ignore_db_dirs_basic-master.opt
@@ -0,0 +1,11 @@
+--ignore-db-dir=a
+--ignore-db-dir=b
+--ignore-db-dir=c
+--ignore-db-dir=
+--ignore-db-dir=d
+--ignore-db-dir x
+--ignore-db-dir=
+--ignore-db-dir=e
+--ignore-db-dir=lost+found
+--ignore-db-dir=.mysqlgui
+--ignore-db-dir=ignored_db
diff --git a/mysql-test/t/ignore_db_dirs_basic.test b/mysql-test/t/ignore_db_dirs_basic.test
new file mode 100644
index 00000000000..9544fc540f9
--- /dev/null
+++ b/mysql-test/t/ignore_db_dirs_basic.test
@@ -0,0 +1,38 @@
+select @@ignore_db_dirs;
+let $MYSQLD_DATADIR= `select @@datadir`;
+
+mkdir $MYSQLD_DATADIR/.mysqlgui;
+mkdir $MYSQLD_DATADIR/.otherdir;
+mkdir $MYSQLD_DATADIR/lost+found;
+mkdir $MYSQLD_DATADIR/ignored_db;
+--echo # Check that SHOW DATABASES ignores all directories from
+--echo # @@ignore_db_dirs and all directories with names starting
+--echo # with '.'
+SHOW DATABASES;
+--error ER_WRONG_DB_NAME
+USE ignored_db;
+--error ER_WRONG_DB_NAME
+SELECT * FROM ignored_db.t1;
+--error ER_WRONG_DB_NAME
+CALL ignored_db.p1();
+SELECT COUNT(*) FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME='ignored_db';
+--error ER_WRONG_DB_NAME
+CREATE DATABASE ignored_db;
+CREATE DATABASE `lost+found`;
+USE `lost+found`;
+CREATE TABLE t1(id INT);
+INSERT INTO t1 VALUES (1), (2);
+SELECT * FROM `lost+found`.t1;
+SHOW DATABASES;
+DROP DATABASE `lost+found`;
+rmdir $MYSQLD_DATADIR/.mysqlgui;
+rmdir $MYSQLD_DATADIR/.otherdir;
+rmdir $MYSQLD_DATADIR/lost+found;
+rmdir $MYSQLD_DATADIR/ignored_db;
+
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.ignore_db_dirs = 'aha';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@local.ignore_db_dirs = 'aha';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@ignore_db_dirs = 'aha';