another post-fix patch for MDEV-5850: MySQL Bug#21317: SHOW CREATE DATABASE does not obey to lower_case_table_names

(for case-insensitive filesystems)

sql/events.cc:
  for "SHOW EVENTS IN db_name"
sql/sp_head.h:
  for "CREATE EVENT", and everything SP-related
sql/sql_acl.cc:
  privilege check for mysql_change_db()
sql/sql_db.cc:
  for metadata locking of db names
sql/sql_parse.cc:
  any_db is a constant, it is not writable
sql/sql_show.cc:
  for SHOW CREATE TRIGGER and other trigger-related statements

6 files changed, 45 insertions, 18 deletions

diff --git a/sql/events.cc b/sql/events.cc
index 505710b3ccd..0c0fb0d5a38 100644
--- a/sql/events.cc
+++ b/sql/events.cc
@@ -764,6 +764,9 @@ Events::fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */)
                      NULL, NULL, 0, 0))
       DBUG_RETURN(1);
     db= thd->lex->select_lex.db;
+
+    if (lower_case_table_names)
+      my_casedn_str(system_charset_info, db);
   }
   ret= db_repository->fill_schema_events(thd, tables, db);
 
diff --git a/sql/sp_head.h b/sql/sp_head.h
index c1fb455e103..cc598186d08 100644
--- a/sql/sp_head.h
+++ b/sql/sp_head.h
@@ -122,6 +122,8 @@ public:
   sp_name(LEX_STRING db, LEX_STRING name, bool use_explicit_name)
     : m_db(db), m_name(name), m_explicit_name(use_explicit_name)
   {
+    if (lower_case_table_names && m_db.str)
+      m_db.length= my_casedn_str(files_charset_info, m_db.str);
     m_qname.str= 0;
     m_qname.length= 0;
   }
diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index 4b139405671..130113c17f1 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -7118,16 +7118,22 @@ bool check_grant_db(THD *thd, const char *db)
 {
   Security_context *sctx= thd->security_ctx;
   char helping [SAFE_NAME_LEN + USERNAME_LENGTH+2], *end;
-  char helping2 [SAFE_NAME_LEN + USERNAME_LENGTH+2];
+  char helping2 [SAFE_NAME_LEN + USERNAME_LENGTH+2], *tmp_db;
   uint len, UNINIT_VAR(len2);
   bool error= TRUE;
 
-  end= strmov(helping, sctx->priv_user) + 1;
-  end= strnmov(end, db, helping + sizeof(helping) - end);
+  tmp_db= strmov(helping, sctx->priv_user) + 1;
+  end= strnmov(tmp_db, db, helping + sizeof(helping) - tmp_db);
 
   if (end >= helping + sizeof(helping)) // db name was truncated
     return 1;                           // no privileges for an invalid db name
 
+  if (lower_case_table_names)
+  {
+    end = tmp_db + my_casedn_str(files_charset_info, tmp_db);
+    db=tmp_db;
+  }
+
   len= (uint) (end - helping) + 1;
 
   /*
diff --git a/sql/sql_db.cc b/sql/sql_db.cc
index 6c823e0480c..063b90a6780 100644
--- a/sql/sql_db.cc
+++ b/sql/sql_db.cc
@@ -579,7 +579,17 @@ int mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create_info,
     DBUG_RETURN(-1);
   }
 
-  if (lock_schema_name(thd, db))
+  char db_tmp[SAFE_NAME_LEN], *dbnorm;
+  if (lower_case_table_names)
+  {
+    strmake_buf(db_tmp, db);
+    my_casedn_str(system_charset_info, db_tmp);
+    dbnorm= db_tmp;
+  }
+  else
+    dbnorm= db;
+
+  if (lock_schema_name(thd, dbnorm))
     DBUG_RETURN(-1);
 
   /* Check directory */
@@ -783,7 +793,17 @@ bool mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent)
   Drop_table_error_handler err_handler;
   DBUG_ENTER("mysql_rm_db");
 
-  if (lock_schema_name(thd, db))
+  char db_tmp[SAFE_NAME_LEN], *dbnorm;
+  if (lower_case_table_names)
+  {
+    strmake_buf(db_tmp, db);
+    my_casedn_str(system_charset_info, db_tmp);
+    dbnorm= db_tmp;
+  }
+  else
+    dbnorm= db;
+
+  if (lock_schema_name(thd, dbnorm))
     DBUG_RETURN(true);
 
   length= build_table_filename(path, sizeof(path) - 1, db, "", "", 0);
@@ -808,7 +828,7 @@ bool mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent)
     }
   }
 
-  if (find_db_tables_and_rm_known_files(thd, dirp, db, path, &tables))
+  if (find_db_tables_and_rm_known_files(thd, dirp, dbnorm, path, &tables))
     goto exit;
 
   /*
@@ -825,7 +845,7 @@ bool mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent)
   /* Lock all tables and stored routines about to be dropped. */
   if (lock_table_names(thd, tables, NULL, thd->variables.lock_wait_timeout,
                        0) ||
-      lock_db_routines(thd, db))
+      lock_db_routines(thd, dbnorm))
     goto exit;
 
   if (!in_bootstrap)
@@ -872,10 +892,10 @@ bool mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent)
 
     ha_drop_database(path);
     tmp_disable_binlog(thd);
-    query_cache_invalidate1(thd, db);
-    (void) sp_drop_db_routines(thd, db); /* @todo Do not ignore errors */
+    query_cache_invalidate1(thd, dbnorm);
+    (void) sp_drop_db_routines(thd, dbnorm); /* @todo Do not ignore errors */
 #ifdef HAVE_EVENT_SCHEDULER
-    Events::drop_schema_events(thd, db);
+    Events::drop_schema_events(thd, dbnorm);
 #endif
     reenable_binlog(thd);
 
@@ -1013,13 +1033,6 @@ static bool find_db_tables_and_rm_known_files(THD *thd, MY_DIR *dirp,
   /* Now put the tables in the list */
   tot_list_next_local= tot_list_next_global= &tot_list;
 
-  if (lower_case_table_names)
-  {
-    /* Change database name to lower case for comparision */
-    db.str= thd->strmake(db.str, db.length);
-    db.length= my_casedn_str(files_charset_info, db.str);
-  }
-
   for (size_t idx=0; idx < files.elements(); idx++)
   {
     LEX_STRING *table= files.at(idx);
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 6a5073be3a7..055317f0445 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -6758,7 +6758,7 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
   {
     if (table->table.length)
       table->table.length= my_casedn_str(files_charset_info, table->table.str);
-    if (ptr->db_length)
+    if (ptr->db_length && ptr->db != any_db)
       ptr->db_length= my_casedn_str(files_charset_info, ptr->db);
   }
       
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index 43a5d1ffec7..15d353c087a 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -9381,6 +9381,9 @@ TABLE_LIST *get_trigger_table(THD *thd, const sp_name *trg_name)
   db= trg_name->m_db;
 
   db.str= thd->strmake(db.str, db.length);
+  if (lower_case_table_names)
+    db.length= my_casedn_str(files_charset_info, db.str);
+
   tbl_name.str= thd->strmake(tbl_name.str, tbl_name.length);
 
   if (db.str == NULL || tbl_name.str == NULL)