Fix for bug#15851 Unlistable directories yield no info from information_schema

  to skip directories which are not allowed for read

mysql-test/r/information_schema.result

@@ -1084,3 +1084,8 @@ DROP TABLE t1;
 DROP VIEW v1;
 DROP FUNCTION func1;
 DROP FUNCTION func2;
+create database mysqltest;
+create table mysqltest.t1(a int);
+select table_schema from information_schema.tables where table_schema='mysqltest';
+table_schema
+drop database mysqltest;

mysql-test/t/information_schema.test

@@ -790,3 +790,13 @@ DROP TABLE t1;
 DROP VIEW v1;
 DROP FUNCTION func1;
 DROP FUNCTION func2;
+
+#
+# Bug #15851 Unlistable directories yield no info from information_schema
+#
+create database mysqltest;
+create table mysqltest.t1(a int);
+--exec chmod -r $MYSQL_TEST_DIR/var/master-data/mysqltest
+select table_schema from information_schema.tables where table_schema='mysqltest';
+--exec chmod +r $MYSQL_TEST_DIR/var/master-data/mysqltest
+drop database mysqltest;

mysys/my_lib.c

@@ -170,6 +170,8 @@ MY_DIR	*my_dir(const char *path, myf MyFlags)
       bzero(finfo.mystat, sizeof(MY_STAT));
       VOID(strmov(tmp_file,dp->d_name));
       VOID(my_stat(tmp_path, finfo.mystat, MyFlags));
+      if (!(finfo.mystat->st_mode & MY_S_IREAD))
+        continue;
     }
     else
       finfo.mystat= NULL;