MDEV-5850: MySQL Bug#21317: SHOW CREATE DATABASE does not obey to lower_case_table_names

Bug #3329 Incomplete lower_case_table_names=2 implementation

The problem was that check_db_name() converted database names to lower case also in case of lower_case_table_names=2.

Fixed by removing the conversion in check_db_name for lower_case_table_names = 2 and instead converting db name to
lower case at same places as table names are converted.

Fixed bug that SHOW CREATE DATABASE FOO showed information for database 'foo'.

I also removed some checks of lower_case_table_names when it was enough to use table_alias_charset.


mysql-test/mysql-test-run.pl:
  Added --use-copy argument to force mysql-test-run to copy files instead of doing symlinks. This is needed when you run
  with test directory on another file system
mysql-test/r/lowercase_table.result:
  Updated results
mysql-test/r/lowercase_table2.result:
  Updated results
mysql-test/suite/parts/r/partition_mgm_lc2_innodb.result:
  Updated results
mysql-test/suite/parts/r/partition_mgm_lc2_memory.result:
  Updated results
mysql-test/suite/parts/r/partition_mgm_lc2_myisam.result:
  Updated results
mysql-test/t/lowercase_table.test:
  Added tests with mixed case databases
mysql-test/t/lowercase_table2.test:
  Added tests with mixed case databases
sql/log.cc:
  Don't check lower_case_table_names when we can use table_alias_charset
sql/sql_base.cc:
  Don't check lower_case_table_names when we can use table_alias_charset
sql/sql_db.cc:
  Use cmp_db_names() for checking if current database changed.
  mysql_rm_db() now converts db to lower case if lower_case_table_names was used.
  Changed database options cache to use table_alias_charset. This fixed a bug where SHOW CREATE DATABASE showed wrong information.
sql/sql_parse.cc:
  Change also db name to lower case when file names are changed.
  Don't need to story copy of database name anymore when lower_case_table_names == 2 as check_db_name() don't convert in this case.
  Updated arguments to mysqld_show_create_db().
  When adding table to TABLE_LIST also convert db name to lower case if needed (same way as we do with table names).
sql/sql_show.cc:
  mysqld_show_create_db() now also takes original name as argument for output to user.
sql/sql_show.h:
  Updated prototype for mysqld_show_create_db()
sql/sql_table.cc:
  In mysql_rename_table(), do same conversions to database name as we do for the file name

8 files changed, 96 insertions, 76 deletions

diff --git a/sql/log.cc b/sql/log.cc
index 1943be2817f..e7a4c82b0b4 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -542,25 +542,19 @@ int check_if_log_table(const TABLE_LIST *table,
 {
   int result= 0;
   if (table->db_length == 5 &&
-      !(lower_case_table_names ?
-        my_strcasecmp(system_charset_info, table->db, "mysql") :
-        strcmp(table->db, "mysql")))
+      !my_strcasecmp(table_alias_charset, table->db, "mysql"))
   {
     const char *table_name= table->table_name;
 
     if (table->table_name_length == 11 &&
-        !(lower_case_table_names ?
-          my_strcasecmp(system_charset_info,
-                        table_name, "general_log") :
-          strcmp(table_name, "general_log")))
+        !my_strcasecmp(table_alias_charset, table_name, "general_log"))
     {
       result= QUERY_LOG_GENERAL;
       goto end;
     }
 
-    if (table->table_name_length == 8 && !(lower_case_table_names ?
-      my_strcasecmp(system_charset_info, table_name, "slow_log") :
-      strcmp(table_name, "slow_log")))
+    if (table->table_name_length == 8 &&
+        !my_strcasecmp(table_alias_charset, table_name, "slow_log"))
     {
       result= QUERY_LOG_SLOW;
       goto end;
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index fba5708adfe..47db5762cc8 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -1372,9 +1372,7 @@ retry:
     /* Skip if table alias does not match. */
     if (check_alias)
     {
-      if (lower_case_table_names ?
-          my_strcasecmp(files_charset_info, t_alias, res->alias) :
-          strcmp(t_alias, res->alias))
+      if (my_strcasecmp(table_alias_charset, t_alias, res->alias))
         goto next;
     }
 
diff --git a/sql/sql_db.cc b/sql/sql_db.cc
index bf55a20f2d9..6c823e0480c 100644
--- a/sql/sql_db.cc
+++ b/sql/sql_db.cc
@@ -78,6 +78,29 @@ typedef struct my_dbopt_st
 } my_dbopt_t;
 
 
+/**
+  Return TRUE if db1_name is equal to db2_name, FALSE otherwise.
+
+  The function allows to compare database names according to the MariaDB
+  rules. The database names db1 and db2 are equal if:
+     - db1 is NULL and db2 is NULL;
+     or
+     - db1 is not-NULL, db2 is not-NULL, db1 is equal to db2 in
+     table_alias_charset
+
+  This is the same rules as we use for filenames.
+*/
+
+static inline bool
+cmp_db_names(const char *db1_name,
+             const char *db2_name)
+{
+  return ((!db1_name && !db2_name) ||
+          (db1_name && db2_name &&
+           my_strcasecmp(table_alias_charset, db1_name, db2_name) == 0));
+}
+
+
 /*
   Function we use in the creation of our hash to get key.
 */
@@ -159,8 +182,7 @@ bool my_dboptions_cache_init(void)
   if (!dboptions_init)
   {
     dboptions_init= 1;
-    error= my_hash_init(&dboptions, lower_case_table_names ?
-                        &my_charset_bin : system_charset_info,
+    error= my_hash_init(&dboptions, table_alias_charset,
                         32, 0, 0, (my_hash_get_key) dboptions_get_key,
                         free_dbopt,0);
   }
@@ -192,8 +214,7 @@ void my_dbopt_cleanup(void)
 {
   mysql_rwlock_wrlock(&LOCK_dboptions);
   my_hash_free(&dboptions);
-  my_hash_init(&dboptions, lower_case_table_names ? 
-               &my_charset_bin : system_charset_info,
+  my_hash_init(&dboptions, table_alias_charset,
                32, 0, 0, (my_hash_get_key) dboptions_get_key,
                free_dbopt,0);
   mysql_rwlock_unlock(&LOCK_dboptions);
@@ -762,7 +783,6 @@ 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))
     DBUG_RETURN(true);
 
@@ -966,7 +986,7 @@ exit:
     SELECT DATABASE() in the future). For this we free() thd->db and set
     it to 0.
   */
-  if (thd->db && !strcmp(thd->db, db) && !error)
+  if (thd->db && cmp_db_names(thd->db, db) && !error)
     mysql_change_db_impl(thd, NULL, 0, thd->variables.collation_server);
   my_dirend(dirp);
   DBUG_RETURN(error);
@@ -993,6 +1013,13 @@ 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);
@@ -1300,27 +1327,6 @@ static void backup_current_db_name(THD *thd,
 
 
 /**
-  Return TRUE if db1_name is equal to db2_name, FALSE otherwise.
-
-  The function allows to compare database names according to the MySQL
-  rules. The database names db1 and db2 are equal if:
-     - db1 is NULL and db2 is NULL;
-     or
-     - db1 is not-NULL, db2 is not-NULL, db1 is equal (ignoring case) to
-       db2 in system character set (UTF8).
-*/
-
-static inline bool
-cmp_db_names(const char *db1_name,
-             const char *db2_name)
-{
-  return ((!db1_name && !db2_name) ||
-          (db1_name && db2_name &&
-           my_strcasecmp(system_charset_info, db1_name, db2_name) == 0));
-}
-
-
-/**
   @brief Change the current database and its attributes unconditionally.
 
   @param thd          thread handle
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index f2bbd7462fd..1891aa6147b 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -1435,7 +1435,10 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     lex_start(thd);
     /* Must be before we init the table list. */
     if (lower_case_table_names)
+    {
       table_name.length= my_casedn_str(files_charset_info, table_name.str);
+      db.length= my_casedn_str(files_charset_info, db.str);
+    }
     table_list.init_one_table(db.str, db.length, table_name.str,
                               table_name.length, table_name.str, TL_READ);
     /*
@@ -3869,9 +3872,7 @@ end_with_restore_list:
       prepared statement- safe.
     */
     HA_CREATE_INFO create_info(lex->create_info);
-    char *alias;
-    if (!(alias=thd->strmake(lex->name.str, lex->name.length)) ||
-        check_db_name(&lex->name))
+    if (check_db_name(&lex->name))
     {
       my_error(ER_WRONG_DB_NAME, MYF(0), lex->name.str);
       break;
@@ -3894,8 +3895,7 @@ end_with_restore_list:
 #endif
     if (check_access(thd, CREATE_ACL, lex->name.str, NULL, NULL, 1, 0))
       break;
-    res= mysql_create_db(thd,(lower_case_table_names == 2 ? alias :
-                              lex->name.str), &create_info, 0);
+    res= mysql_create_db(thd, lex->name.str, &create_info, 0);
     break;
   }
   case SQLCOM_DROP_DB:
@@ -3988,14 +3988,20 @@ end_with_restore_list:
   }
   case SQLCOM_SHOW_CREATE_DB:
   {
+    char db_name_buff[NAME_LEN+1];
+    LEX_STRING db_name;
     DBUG_EXECUTE_IF("4x_server_emul",
                     my_error(ER_UNKNOWN_ERROR, MYF(0)); goto error;);
-    if (check_db_name(&lex->name))
+
+    db_name.str= db_name_buff;
+    db_name.length= lex->name.length;
+    strmov(db_name.str, lex->name.str);
+    if (check_db_name(&db_name))
     {
-      my_error(ER_WRONG_DB_NAME, MYF(0), lex->name.str);
+      my_error(ER_WRONG_DB_NAME, MYF(0), db_name);
       break;
     }
-    res= mysqld_show_create_db(thd, lex->name.str, &lex->create_info);
+    res= mysqld_show_create_db(thd, &db_name, &lex->name, &lex->create_info);
     break;
   }
   case SQLCOM_CREATE_EVENT:
@@ -6748,8 +6754,14 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
 
   ptr->alias= alias_str;
   ptr->is_alias= alias ? TRUE : FALSE;
-  if (lower_case_table_names && table->table.length)
-    table->table.length= my_casedn_str(files_charset_info, table->table.str);
+  if (lower_case_table_names)
+  {
+    if (table->table.length)
+      table->table.length= my_casedn_str(files_charset_info, table->table.str);
+    if (ptr->db_length)
+      ptr->db_length= my_casedn_str(files_charset_info, ptr->db);
+  }
+      
   ptr->table_name=table->table.str;
   ptr->table_name_length=table->table.length;
   ptr->lock_type=   lock_type;
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index aa23f01ab7d..43a5d1ffec7 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -1009,9 +1009,10 @@ mysqld_show_create(THD *thd, TABLE_LIST *table_list)
 
   {
     /*
-      Use open_tables() directly rather than open_normal_and_derived_tables().
-      This ensures that close_thread_tables() is not called if open tables fails
-      and the error is ignored. This allows us to handle broken views nicely.
+      Use open_tables() directly rather than
+      open_normal_and_derived_tables().  This ensures that
+      close_thread_tables() is not called if open tables fails and the
+      error is ignored. This allows us to handle broken views nicely.
     */
     uint counter;
     Show_create_error_handler view_error_suppressor(thd, table_list);
@@ -1105,7 +1106,8 @@ exit:
   DBUG_RETURN(error);
 }
 
-bool mysqld_show_create_db(THD *thd, char *dbname,
+bool mysqld_show_create_db(THD *thd, LEX_STRING *dbname,
+                           LEX_STRING *orig_dbname,
                            HA_CREATE_INFO *create_info)
 {
   char buff[2048];
@@ -1123,32 +1125,32 @@ bool mysqld_show_create_db(THD *thd, char *dbname,
   if (test_all_bits(sctx->master_access, DB_ACLS))
     db_access=DB_ACLS;
   else
-    db_access= (acl_get(sctx->host, sctx->ip, sctx->priv_user, dbname, 0) |
+    db_access= (acl_get(sctx->host, sctx->ip, sctx->priv_user, dbname->str, 0) |
 		sctx->master_access);
-  if (!(db_access & DB_ACLS) && check_grant_db(thd,dbname))
+  if (!(db_access & DB_ACLS) && check_grant_db(thd,dbname->str))
   {
     status_var_increment(thd->status_var.access_denied_errors);
     my_error(ER_DBACCESS_DENIED_ERROR, MYF(0),
-             sctx->priv_user, sctx->host_or_ip, dbname);
+             sctx->priv_user, sctx->host_or_ip, dbname->str);
     general_log_print(thd,COM_INIT_DB,ER(ER_DBACCESS_DENIED_ERROR),
-                      sctx->priv_user, sctx->host_or_ip, dbname);
+                      sctx->priv_user, sctx->host_or_ip, orig_dbname->str);
     DBUG_RETURN(TRUE);
   }
 #endif
-  if (is_infoschema_db(dbname))
+  if (is_infoschema_db(dbname->str))
   {
-    dbname= INFORMATION_SCHEMA_NAME.str;
+    *dbname= INFORMATION_SCHEMA_NAME;
     create.default_table_charset= system_charset_info;
   }
   else
   {
-    if (check_db_dir_existence(dbname))
+    if (check_db_dir_existence(dbname->str))
     {
-      my_error(ER_BAD_DB_ERROR, MYF(0), dbname);
+      my_error(ER_BAD_DB_ERROR, MYF(0), dbname->str);
       DBUG_RETURN(TRUE);
     }
 
-    load_db_opt_by_name(thd, dbname, &create);
+    load_db_opt_by_name(thd, dbname->str, &create);
   }
   List<Item> field_list;
   field_list.push_back(new Item_empty_string("Database",NAME_CHAR_LEN));
@@ -1159,12 +1161,12 @@ bool mysqld_show_create_db(THD *thd, char *dbname,
     DBUG_RETURN(TRUE);
 
   protocol->prepare_for_resend();
-  protocol->store(dbname, strlen(dbname), system_charset_info);
+  protocol->store(orig_dbname->str, orig_dbname->length, system_charset_info);
   buffer.length(0);
   buffer.append(STRING_WITH_LEN("CREATE DATABASE "));
   if (create_options & HA_LEX_CREATE_IF_NOT_EXISTS)
     buffer.append(STRING_WITH_LEN("/*!32312 IF NOT EXISTS*/ "));
-  append_identifier(thd, &buffer, dbname, strlen(dbname));
+  append_identifier(thd, &buffer, dbname->str, dbname->length);
 
   if (create.default_table_charset)
   {
diff --git a/sql/sql_show.h b/sql/sql_show.h
index 0416f2fdaba..708a77d74cd 100644
--- a/sql/sql_show.h
+++ b/sql/sql_show.h
@@ -86,7 +86,9 @@ bool append_identifier(THD *thd, String *packet, const char *name,
 void mysqld_list_fields(THD *thd,TABLE_LIST *table, const char *wild);
 int mysqld_dump_create_info(THD *thd, TABLE_LIST *table_list, int fd);
 bool mysqld_show_create(THD *thd, TABLE_LIST *table_list);
-bool mysqld_show_create_db(THD *thd, char *dbname, HA_CREATE_INFO *create);
+bool mysqld_show_create_db(THD *thd, LEX_STRING *db_name,
+                           LEX_STRING *orig_db_name,
+                           HA_CREATE_INFO *create);
 
 void mysqld_list_processes(THD *thd,const char *user,bool verbose);
 int mysqld_show_status(THD *thd);
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index d30eb3169e3..ee3b954168d 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -5132,7 +5132,7 @@ mysql_rename_table(handlerton *base, const char *old_db,
   char from[FN_REFLEN + 1], to[FN_REFLEN + 1],
     lc_from[FN_REFLEN + 1], lc_to[FN_REFLEN + 1];
   char *from_base= from, *to_base= to;
-  char tmp_name[SAFE_NAME_LEN+1];
+  char tmp_name[SAFE_NAME_LEN+1], tmp_db_name[SAFE_NAME_LEN+1];
   handler *file;
   int error=0;
   ulonglong save_bits= thd->variables.option_bits;
@@ -5169,13 +5169,19 @@ mysql_rename_table(handlerton *base, const char *old_db,
   {
     strmov(tmp_name, old_name);
     my_casedn_str(files_charset_info, tmp_name);
-    build_table_filename(lc_from, sizeof(lc_from) - 1, old_db, tmp_name, "",
-                         flags & FN_FROM_IS_TMP);
+    strmov(tmp_db_name, old_db);
+    my_casedn_str(files_charset_info, tmp_db_name);
+
+    build_table_filename(lc_from, sizeof(lc_from) - 1, tmp_db_name, tmp_name,
+                         "", flags & FN_FROM_IS_TMP);
     from_base= lc_from;
 
     strmov(tmp_name, new_name);
     my_casedn_str(files_charset_info, tmp_name);
-    build_table_filename(lc_to, sizeof(lc_to) - 1, new_db, tmp_name, "",
+    strmov(tmp_db_name, new_db);
+    my_casedn_str(files_charset_info, tmp_db_name);
+
+    build_table_filename(lc_to, sizeof(lc_to) - 1, tmp_db_name, tmp_name, "",
                          flags & FN_TO_IS_TMP);
     to_base= lc_to;
   }
diff --git a/sql/table.cc b/sql/table.cc
index 8daf54920cd..268b35c409e 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -3440,10 +3440,11 @@ uint calculate_key_len(TABLE *table, uint key, const uchar *buf,
 
   SYNPOSIS
     check_db_name()
-    org_name		Name of database and length
+    org_name		Name of database
 
   NOTES
-    If lower_case_table_names is set then database is converted to lower case
+    If lower_case_table_names is set to 1 then database name is converted
+    to lower case
 
   RETURN
     0	ok
@@ -3465,13 +3466,12 @@ bool check_db_name(LEX_STRING *org_name)
   if (!name_length || name_length > NAME_LEN)
     return 1;
 
-  if (lower_case_table_names && name != any_db)
-    my_casedn_str(files_charset_info, name);
-
+  if (lower_case_table_names == 1 && name != any_db)
+    org_name->length= my_casedn_str(files_charset_info, name);
   if (db_name_is_in_ignore_db_dirs_list(name))
     return 1;
 
-  return check_table_name(name, name_length, check_for_path_chars);
+  return check_table_name(name, org_name->length, check_for_path_chars);
 }