1 /*
   2  * Copyright (c) 2015, 2020, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /*
  25  * @test
  26  * @requires vm.compMode != "Xcomp"
  27  * @summary Verifies behaviour of Unsafe.allocateMemory
  28  * @library /test/lib
  29  * @modules java.base/jdk.internal.misc
  30  *          java.management
  31  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:MallocMaxTestWords=100m AllocateMemory
  32  */
  33 
  34 import jdk.internal.misc.Unsafe;
  35 import static jdk.test.lib.Asserts.*;
  36 
  37 public class AllocateMemory {
  38     public static void main(String args[]) throws Exception {
  39         Unsafe unsafe = Unsafe.getUnsafe();
  40 
  41         // Allocate a byte, write to the location and read back the value
  42         long address = unsafe.allocateMemory(1);
  43         assertNotEquals(address, 0L);
  44 
  45         unsafe.putByte(address, Byte.MAX_VALUE);
  46         assertEquals(Byte.MAX_VALUE, unsafe.getByte(address));
  47         unsafe.freeMemory(address);
  48 
  49         // Call to allocateMemory() with a negative value should result in an IllegalArgumentException
  50         try {
  51             address = unsafe.allocateMemory(-1);
  52             throw new RuntimeException("Did not get expected IllegalArgumentException");
  53         } catch (IllegalArgumentException e) {
  54             // Expected
  55             assertNotEquals(address, 0L);
  56         }
  57 
  58         // allocateMemory() should throw an OutOfMemoryError when the underlying malloc fails,
  59         // we test this by limiting the malloc using -XX:MallocMaxTestWords
  60         try {
  61             address = unsafe.allocateMemory(100 * 1024 * 1024 * 8);
  62             throw new RuntimeException("Did not get expected OutOfMemoryError");
  63         } catch (OutOfMemoryError e) {
  64             // Expected
  65         }
  66 
  67         // Allocation should fail on a 32-bit system if the aligned-up
  68         // size overflows a size_t
  69         if (Unsafe.ADDRESS_SIZE == 4) {
  70             try {
  71                 address = unsafe.allocateMemory((long)Integer.MAX_VALUE * 2);
  72                 throw new RuntimeException("Did not get expected IllegalArgumentException");
  73             } catch (IllegalArgumentException e) {
  74                 // Expected
  75             }
  76         }
  77 
  78         // Allocation should fail if the aligned-up size overflows a
  79         // Java long
  80         try {
  81             address = unsafe.allocateMemory((long)Long.MAX_VALUE);
  82             throw new RuntimeException("Did not get expected IllegalArgumentException");
  83         } catch (IllegalArgumentException e) {
  84             // Expected
  85         }
  86     }
  87 }