1 files changed, 91 insertions, 0 deletions
diff --git a/tools/fuzzing/interface/harness/FuzzerRunner.cpp b/tools/fuzzing/interface/harness/FuzzerRunner.cpp
new file mode 100644
index 0000000000..fc2094aa59
--- /dev/null
+++ b/tools/fuzzing/interface/harness/FuzzerRunner.cpp
@@ -0,0 +1,91 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * * This Source Code Form is subject to the terms of the Mozilla Public
+ * * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <cstdlib>
+
+#include "FuzzerRunner.h"
+#include "mozilla/Attributes.h"
+#include "prenv.h"
+
+#include "FuzzerTestHarness.h"
+
+namespace mozilla {
+
+// We use a static var 'fuzzerRunner' defined in nsAppRunner.cpp.
+// fuzzerRunner is initialized to nullptr but if this file is linked in,
+// then fuzzerRunner will be set here indicating that
+// we want to call into either LibFuzzer's main or the AFL entrypoint.
+class _InitFuzzer {
+ public:
+  _InitFuzzer() { fuzzerRunner = new FuzzerRunner(); }
+  void InitXPCOM() { mScopedXPCOM = new ScopedXPCOM("Fuzzer"); }
+  void DeinitXPCOM() {
+    if (mScopedXPCOM) delete mScopedXPCOM;
+    mScopedXPCOM = nullptr;
+  }
+
+ private:
+  ScopedXPCOM* mScopedXPCOM;
+} InitLibFuzzer;
+
+static void DeinitXPCOM() { InitLibFuzzer.DeinitXPCOM(); }
+
+int FuzzerRunner::Run(int* argc, char*** argv) {
+  /*
+   * libFuzzer uses exit() calls in several places instead of returning,
+   * so the destructor of ScopedXPCOM is not called in some cases.
+   * For fuzzing, this does not make a difference, but in debug builds
+   * when running a single testcase, this causes an assertion when destroying
+   * global linked lists. For this reason, we allocate ScopedXPCOM on the heap
+   * using the global InitLibFuzzer class, combined with an atexit call to
+   * destroy the ScopedXPCOM instance again.
+   */
+  InitLibFuzzer.InitXPCOM();
+  std::atexit(DeinitXPCOM);
+
+  const char* fuzzerEnv = getenv("FUZZER");
+
+  if (!fuzzerEnv) {
+    fprintf(stderr,
+            "Must specify fuzzing target in FUZZER environment variable\n");
+    exit(1);
+  }
+
+  std::string moduleNameStr(fuzzerEnv);
+  FuzzerFunctions funcs =
+      FuzzerRegistry::getInstance().getModuleFunctions(moduleNameStr);
+  FuzzerInitFunc initFunc = funcs.first;
+  FuzzerTestingFunc testingFunc = funcs.second;
+  if (initFunc) {
+    int ret = initFunc(argc, argv);
+    if (ret) {
+      fprintf(stderr, "Fuzzing Interface: Error: Initialize callback failed\n");
+      exit(1);
+    }
+  }
+
+  if (!testingFunc) {
+    fprintf(stderr, "Fuzzing Interface: Error: No testing callback found\n");
+    exit(1);
+  }
+
+#ifdef LIBFUZZER
+  int ret = mFuzzerDriver(argc, argv, testingFunc);
+#else
+  // For AFL, testingFunc points to the entry function we need.
+  int ret = testingFunc(NULL, 0);
+#endif
+
+  InitLibFuzzer.DeinitXPCOM();
+  return ret;
+}
+
+#ifdef LIBFUZZER
+void FuzzerRunner::setParams(LibFuzzerDriver aDriver) {
+  mFuzzerDriver = aDriver;
+}
+#endif
+
+}  // namespace mozilla