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: 19 virtual int getRandomNumber() { 20 return 4; // chosen by fair dice roll. 21 // guaranteed to be random. 22 } 23 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 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
