From 806b3d861927812a06b077912814dda2518f2480 Mon Sep 17 00:00:00 2001
From: Dylan Katz <dylan.katz@leviathansecurity.com>
Date: Fri, 11 Sep 2020 11:03:02 -0700
Subject: [PATCH] Removed RWLock fuzzer

The class being fuzzed here was too simple for a fuzzer to be effective at finding crashes that were not working as intended.
To resolve the issue noted in 163775285 would require the fuzzer to simply use RWLock exactly as intended, defeating the point of fuzzing it.
Because of this, we have made the decision to remove this class. It should have a fairly small impact on coverage. In the future,
perhaps a better approach would be fuzzing pthread's rwlock methods directly.
Test: Made sure the project still builds without RWLock_fuzz.

Signed-off-by: Dylan Katz <dylan.katz@leviathansecurity.com>
Change-Id: Id5e77d053dc800a982176802dc506d26b54d810f
---
 libutils/Android.bp      |  6 -----
 libutils/RWLock_fuzz.cpp | 50 ----------------------------------------
 2 files changed, 56 deletions(-)
 delete mode 100755 libutils/RWLock_fuzz.cpp

diff --git a/libutils/Android.bp b/libutils/Android.bp
index 926e3d764..dd9fea041 100644
--- a/libutils/Android.bp
+++ b/libutils/Android.bp
@@ -268,12 +268,6 @@ cc_fuzz {
     srcs: ["StopWatch_fuzz.cpp"],
 }
 
-cc_fuzz {
-    name: "libutils_fuzz_rwlock",
-    defaults: ["libutils_fuzz_defaults"],
-    srcs: ["RWLock_fuzz.cpp"],
-}
-
 cc_fuzz {
     name: "libutils_fuzz_refbase",
     defaults: ["libutils_fuzz_defaults"],
diff --git a/libutils/RWLock_fuzz.cpp b/libutils/RWLock_fuzz.cpp
deleted file mode 100755
index e07590549..000000000
--- a/libutils/RWLock_fuzz.cpp
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- * Copyright 2020 The Android Open Source Project
- *
- * 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.
- */
-#include <functional>
-
-#include "fuzzer/FuzzedDataProvider.h"
-#include "utils/RWLock.h"
-
-static constexpr int MAX_OPERATIONS = 100;
-static constexpr int MAX_NAME_LEN = 2048;
-
-static const std::vector<std::function<void(android::RWLock*)>> operations = {
-        [](android::RWLock* lock) -> void {
-            // This might return a non-zero value if already locked
-            // Either way we are definitely locked now.
-            lock->tryWriteLock();
-        },
-        [](android::RWLock* lock) -> void { lock->tryReadLock(); },
-        [](android::RWLock* lock) -> void { lock->unlock(); },
-};
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-    FuzzedDataProvider dataProvider(data, size);
-    std::string nameStr = dataProvider.ConsumeRandomLengthString(MAX_NAME_LEN);
-    int type = dataProvider.ConsumeIntegral<int>();
-    android::RWLock rwLock = android::RWLock(type, nameStr.c_str());
-    std::vector<uint8_t> opsToRun = dataProvider.ConsumeRemainingBytes<uint8_t>();
-    int opsRun = 0;
-    for (auto it : opsToRun) {
-        if (opsRun++ >= MAX_OPERATIONS) {
-            break;
-        }
-        it = it % operations.size();
-        operations[it](&rwLock);
-    }
-    rwLock.unlock();
-    return 0;
-}