Bug #21251297 and Bug #21436364: Make some P_S tables world readable

The MySQL ACL system does not currently support granting stuff to public.
So the only currently possible fix is to make performance schema override
the ACL code and return that the tables are accessible to public.

Fixed by reverting parts of the fix for bug #14569746 pertaining to
PERFORMANCE_SCHEMA.SESSION_ACCOUNT_CONNECT_ATTR, namely re-introducing
the PFS_readonly_world_acl derived class and returning it into the tables
share.

Also used PFS_readonly_world_acl (and another derivate
of PFS_truncatable_world_acl) to ensure performance_schema.session_status,
performance_schema.global_status, performance_schema.session_variables and
performance_schema.global_variables are using the world readable derivates
too.
Test cases updated.

Author: gkodinov

mysql-test/suite/perfschema/r/connect_attrs.result

@@ -35,9 +35,11 @@ SELECT COUNT(DISTINCT PROCESSLIST_ID)
 FROM performance_schema.session_connect_attrs;
 COUNT(DISTINCT PROCESSLIST_ID)
 2
+# must return 1
 SELECT COUNT(DISTINCT PROCESSLIST_ID)
 FROM performance_schema.session_account_connect_attrs;
-ERROR 42000: SELECT command denied to user 'wl5924'@'localhost' for table 'session_account_connect_attrs'
+COUNT(DISTINCT PROCESSLIST_ID)
+1
 SELECT COUNT(DISTINCT PROCESSLIST_ID)
 FROM performance_schema.session_connect_attrs;
 ERROR 42000: SELECT command denied to user 'wl5924'@'localhost' for table 'session_connect_attrs'

mysql-test/suite/perfschema/t/connect_attrs.test

@@ -57,7 +57,7 @@ SELECT COUNT(DISTINCT PROCESSLIST_ID)
   FROM performance_schema.session_connect_attrs;
 
 connection non_privileged_user;
---error ER_TABLEACCESS_DENIED_ERROR
+--echo # must return 1
 SELECT COUNT(DISTINCT PROCESSLIST_ID)
   FROM performance_schema.session_account_connect_attrs;
 

storage/perfschema/pfs_engine_table.cc

@@ -843,6 +843,19 @@ PFS_readonly_acl::check(ulong want_access, ulong *save_priv) const
   return ACL_INTERNAL_ACCESS_CHECK_GRANT;
 }
 
+
+PFS_readonly_world_acl pfs_readonly_world_acl;
+
+ACL_internal_access_result
+PFS_readonly_world_acl::check(ulong want_access, ulong *save_priv) const
+{
+  ACL_internal_access_result res= PFS_readonly_acl::check(want_access, save_priv);
+  if (res == ACL_INTERNAL_ACCESS_CHECK_GRANT)
+    res= ACL_INTERNAL_ACCESS_GRANTED;
+  return res;
+}
+
+
 PFS_truncatable_acl pfs_truncatable_acl;
 
 ACL_internal_access_result
@@ -858,6 +871,19 @@ PFS_truncatable_acl::check(ulong want_access, ulong *save_priv) const
   return ACL_INTERNAL_ACCESS_CHECK_GRANT;
 }
 
+
+PFS_truncatable_world_acl pfs_truncatable_world_acl;
+
+ACL_internal_access_result
+PFS_truncatable_world_acl::check(ulong want_access, ulong *save_priv) const
+{
+  ACL_internal_access_result res= PFS_truncatable_acl::check(want_access, save_priv);
+  if (res == ACL_INTERNAL_ACCESS_CHECK_GRANT)
+    res= ACL_INTERNAL_ACCESS_GRANTED;
+  return res;
+}
+
+
 PFS_updatable_acl pfs_updatable_acl;
 
 ACL_internal_access_result

storage/perfschema/pfs_engine_table.h

@@ -403,6 +403,45 @@ class PFS_unknown_acl : public ACL_internal_table_access
 /** Singleton instance of PFS_unknown_acl. */
 extern PFS_unknown_acl pfs_unknown_acl;
 
+
+/**
+  Privileges for world readable tables.
+*/
+class PFS_readonly_world_acl : public PFS_readonly_acl
+{
+public:
+  PFS_readonly_world_acl()
+  {}
+
+  ~PFS_readonly_world_acl()
+  {}
+  virtual ACL_internal_access_result check(ulong want_access, ulong *save_priv) const;
+};
+
+
+/** Singleton instance of PFS_readonly_world_acl */
+extern PFS_readonly_world_acl pfs_readonly_world_acl;
+
+
+/**
+Privileges for world readable truncatable tables.
+*/
+class PFS_truncatable_world_acl : public PFS_truncatable_acl
+{
+public:
+  PFS_truncatable_world_acl()
+  {}
+
+  ~PFS_truncatable_world_acl()
+  {}
+  virtual ACL_internal_access_result check(ulong want_access, ulong *save_priv) const;
+};
+
+
+/** Singleton instance of PFS_readonly_world_acl */
+extern PFS_truncatable_world_acl pfs_truncatable_world_acl;
+
+
 /** Position of a cursor, for simple iterations. */
 struct PFS_simple_index
 {

storage/perfschema/table_global_status.cc

@@ -50,7 +50,7 @@ PFS_engine_table_share
 table_global_status::m_share=
 {
   { C_STRING_WITH_LEN("global_status") },
-  &pfs_truncatable_acl,
+  &pfs_truncatable_world_acl,
   table_global_status::create,
   NULL, /* write_row */
   table_global_status::delete_all_rows,

storage/perfschema/table_global_variables.cc

@@ -50,7 +50,7 @@ PFS_engine_table_share
 table_global_variables::m_share=
 {
   { C_STRING_WITH_LEN("global_variables") },
-  &pfs_readonly_acl,
+  &pfs_readonly_world_acl,
   table_global_variables::create,
   NULL, /* write_row */
   NULL, /* delete_all_rows */

storage/perfschema/table_session_account_connect_attrs.cc

@@ -21,7 +21,7 @@ PFS_engine_table_share
 table_session_account_connect_attrs::m_share=
 {
   { C_STRING_WITH_LEN("session_account_connect_attrs") },
-  &pfs_readonly_acl,
+  &pfs_readonly_world_acl,
   table_session_account_connect_attrs::create,
   NULL, /* write_row */
   NULL, /* delete_all_rows */

storage/perfschema/table_session_status.cc

@@ -50,7 +50,7 @@ PFS_engine_table_share
 table_session_status::m_share=
 {
   { C_STRING_WITH_LEN("session_status") },
-  &pfs_readonly_acl,
+  &pfs_readonly_world_acl,
   table_session_status::create,
   NULL, /* write_row */
   NULL, /* delete_all_rows */

storage/perfschema/table_session_variables.cc

@@ -50,7 +50,7 @@ PFS_engine_table_share
 table_session_variables::m_share=
 {
   { C_STRING_WITH_LEN("session_variables") },
-  &pfs_readonly_acl,
+  &pfs_readonly_world_acl,
   table_session_variables::create,
   NULL, /* write_row */
   NULL, /* delete_all_rows */