1 files changed, 55 insertions, 40 deletions

diff --git a/sql/sql_db.cc b/sql/sql_db.cc
index bc6b30040d6..3ea6821ef80 100644
--- a/sql/sql_db.cc
+++ b/sql/sql_db.cc
@@ -595,7 +595,8 @@ static long mysql_rm_known_files(THD *thd, MY_DIR *dirp, const char *db,
     1	error
 */
 
-bool mysql_change_db(THD *thd, const char *name)
+bool mysql_change_db(THD *thd, const char *name,
+		     bool empty_is_ok, bool no_access_check)
 {
   int length, db_length;
   char *dbname=my_strdup((char*) name,MYF(MY_WME));
@@ -604,62 +605,76 @@ bool mysql_change_db(THD *thd, const char *name)
   HA_CREATE_INFO create;
   DBUG_ENTER("mysql_change_db");
 
-  if (!dbname || !(db_length=strip_sp(dbname)))
+  if ((!dbname || !(db_length=strip_sp(dbname))) && !empty_is_ok)
   {
     x_free(dbname);				/* purecov: inspected */
     send_error(thd,ER_NO_DB_ERROR);	/* purecov: inspected */
     DBUG_RETURN(1);				/* purecov: inspected */
   }
-  if ((db_length > NAME_LEN) || check_db_name(dbname))
+  if (!empty_is_ok || (dbname && db_length))
   {
-    net_printf(thd, ER_WRONG_DB_NAME, dbname);
-    x_free(dbname);
-    DBUG_RETURN(1);
+    if ((db_length > NAME_LEN) || check_db_name(dbname))
+    {
+      net_printf(thd, ER_WRONG_DB_NAME, dbname);
+      x_free(dbname);
+      DBUG_RETURN(1);
+    }
   }
   DBUG_PRINT("info",("Use database: %s", dbname));
-#ifndef NO_EMBEDDED_ACCESS_CHECKS
-  if (test_all_bits(thd->master_access,DB_ACLS))
-    db_access=DB_ACLS;
-  else
-    db_access= (acl_get(thd->host,thd->ip, thd->priv_user,dbname,0) |
-		thd->master_access);
-  if (!(db_access & DB_ACLS) && (!grant_option || check_grant_db(thd,dbname)))
+  if (!empty_is_ok || (dbname && db_length))
   {
-    net_printf(thd,ER_DBACCESS_DENIED_ERROR,
-	       thd->priv_user,
-	       thd->priv_host,
-	       dbname);
-    mysql_log.write(thd,COM_INIT_DB,ER(ER_DBACCESS_DENIED_ERROR),
-		    thd->priv_user,
-		    thd->priv_host,
-		    dbname);
-    my_free(dbname,MYF(0));
-    DBUG_RETURN(1);
-  }
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
+    if (! no_access_check)
+    {
+      if (test_all_bits(thd->master_access,DB_ACLS))
+	db_access=DB_ACLS;
+      else
+	db_access= (acl_get(thd->host,thd->ip, thd->priv_user,dbname,0) |
+		    thd->master_access);  
+      if (!(db_access & DB_ACLS) &&
+	  (!grant_option || check_grant_db(thd,dbname)))
+      {
+	net_printf(thd,ER_DBACCESS_DENIED_ERROR,
+		   thd->priv_user,
+		   thd->priv_host,
+		   dbname);
+	mysql_log.write(thd,COM_INIT_DB,ER(ER_DBACCESS_DENIED_ERROR),
+			thd->priv_user,
+			thd->priv_host,
+			dbname);
+	my_free(dbname,MYF(0));
+	DBUG_RETURN(1);
+      }
+    }
 #endif
-  (void) sprintf(path,"%s/%s",mysql_data_home,dbname);
-  length=unpack_dirname(path,path);		// Convert if not unix
-  if (length && path[length-1] == FN_LIBCHAR)
-    path[length-1]=0;				// remove ending '\'
-  if (access(path,F_OK))
-  {
-    net_printf(thd,ER_BAD_DB_ERROR,dbname);
-    my_free(dbname,MYF(0));
-    DBUG_RETURN(1);
+    (void) sprintf(path,"%s/%s",mysql_data_home,dbname);
+    length=unpack_dirname(path,path);		// Convert if not unix
+    if (length && path[length-1] == FN_LIBCHAR)
+      path[length-1]=0;				// remove ending '\'
+    if (access(path,F_OK))
+    {
+      net_printf(thd,ER_BAD_DB_ERROR,dbname);
+      my_free(dbname,MYF(0));
+      DBUG_RETURN(1);
+    }
   }
   send_ok(thd);
   x_free(thd->db);
   thd->db=dbname;				// THD::~THD will free this
   thd->db_length=db_length;
+  if (!empty_is_ok || (dbname && db_length))
+  {
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
-  thd->db_access=db_access;
+    if (! no_access_check)
+      thd->db_access=db_access;
 #endif
-  strmov(path+unpack_dirname(path,path), MY_DB_OPT_FILE);
-  load_db_opt(thd, path, &create);
-  thd->db_charset= create.default_table_charset ?
-		   create.default_table_charset :
-		   thd->variables.collation_server;
-  thd->variables.collation_database= thd->db_charset;
+    strmov(path+unpack_dirname(path,path), MY_DB_OPT_FILE);
+    load_db_opt(thd, path, &create);
+    thd->db_charset= create.default_table_charset ?
+      create.default_table_charset :
+      thd->variables.collation_server;
+    thd->variables.collation_database= thd->db_charset;
+  }
   DBUG_RETURN(0);
 }