1 /*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 class A {
18 public:
getRandomNumber()19 virtual int getRandomNumber() {
20 return 4; // chosen by fair dice roll.
21 // guaranteed to be random.
22 }
23
~A()24 virtual ~A() {}
25 };
26
27 A a;
28
29 // nested macros to make it easy to define a large amount of read-only data
30 // which will require relocation.
31 #define A_16 &a, &a, &a, &a, &a, &a, &a, &a, &a, &a, &a, &a, &a, &a, &a, &a,
32 #define A_128 A_16 A_16 A_16 A_16 A_16 A_16 A_16 A_16
33 #define A_1024 A_128 A_128 A_128 A_128 A_128 A_128 A_128 A_128
34
35 extern "C" A* const lots_of_relro[] = {
36 A_1024 A_1024 A_1024 A_1024 A_1024 A_1024 A_1024 A_1024
37 };
38
getRandomNumber()39 extern "C" int getRandomNumber() {
40 // access the relro section (twice, in fact, once for the pointer, and once
41 // for the vtable of A) to check it's actually there.
42 return lots_of_relro[0]->getRandomNumber();
43 }
44