diff options
Diffstat (limited to 'agent/src/jmh/java/com/code_intelligence/jazzer/instrumentor/UnsafeCoverageMap.java')
-rw-r--r-- | agent/src/jmh/java/com/code_intelligence/jazzer/instrumentor/UnsafeCoverageMap.java | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/agent/src/jmh/java/com/code_intelligence/jazzer/instrumentor/UnsafeCoverageMap.java b/agent/src/jmh/java/com/code_intelligence/jazzer/instrumentor/UnsafeCoverageMap.java new file mode 100644 index 00000000..cf73928d --- /dev/null +++ b/agent/src/jmh/java/com/code_intelligence/jazzer/instrumentor/UnsafeCoverageMap.java @@ -0,0 +1,59 @@ +// Copyright 2022 Code Intelligence GmbH +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package com.code_intelligence.jazzer.instrumentor; + +import java.lang.reflect.Field; +import sun.misc.Unsafe; + +public final class UnsafeCoverageMap { + private static final Unsafe UNSAFE; + + static { + Unsafe unsafe; + try { + Field f = Unsafe.class.getDeclaredField("theUnsafe"); + f.setAccessible(true); + unsafe = (Unsafe) f.get(null); + } catch (IllegalAccessException | NoSuchFieldException e) { + e.printStackTrace(); + System.exit(1); + // Not reached. + unsafe = null; + } + UNSAFE = unsafe; + } + + // The current target, JsonSanitizer, uses less than 2048 coverage counters. + private static final long NUM_COUNTERS = 4096; + private static final long countersAddress = UNSAFE.allocateMemory(NUM_COUNTERS); + + static { + UNSAFE.setMemory(countersAddress, NUM_COUNTERS, (byte) 0); + } + + public static void enlargeIfNeeded(int nextId) { + // Statically sized counters buffer. + } + + public static void recordCoverage(final int id) { + final long address = countersAddress + id; + final byte counter = UNSAFE.getByte(address); + if (counter == -1) { + UNSAFE.putByte(address, (byte) 1); + } else { + UNSAFE.putByte(address, (byte) (counter + 1)); + } + } +} |