Add fuzzers for libutils classes

Adds fuzzers for BitSet, FileMap, String8, String16, and Vector.
Test: Ran fuzzers on Android Pixel 3a. Aggregate coverage was 1.2% (this is far lower than true coverage due to shared libraries being counted)

Change-Id: I739216fe88afa51dc2f73b857da91116853382f0

Removed unneeded cflags, moved libbase to defaults

Test: Built Android.bp successfully

Signed-off-by: Dylan Katz <dylan.katz@leviathansecurity.com>
Change-Id: I739216fe88afa51dc2f73b857da91116853382f0
diff --git a/libutils/FileMap_fuzz.cpp b/libutils/FileMap_fuzz.cpp
new file mode 100644
index 0000000..d800564
--- /dev/null
+++ b/libutils/FileMap_fuzz.cpp
@@ -0,0 +1,50 @@
+/*
+ * 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 <iostream>
+
+#include "android-base/file.h"
+#include "fuzzer/FuzzedDataProvider.h"
+#include "utils/FileMap.h"
+
+static constexpr uint16_t MAX_STR_SIZE = 256;
+static constexpr uint8_t MAX_FILENAME_SIZE = 32;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+    FuzzedDataProvider dataProvider(data, size);
+    TemporaryFile tf;
+    // Generate file contents
+    std::string contents = dataProvider.ConsumeRandomLengthString(MAX_STR_SIZE);
+    // If we have string contents, dump them into the file.
+    // Otherwise, just leave it as an empty file.
+    if (contents.length() > 0) {
+        const char* bytes = contents.c_str();
+        android::base::WriteStringToFd(bytes, tf.fd);
+    }
+    android::FileMap m;
+    // Generate create() params
+    std::string orig_name = dataProvider.ConsumeRandomLengthString(MAX_FILENAME_SIZE);
+    size_t length = dataProvider.ConsumeIntegralInRange<size_t>(1, SIZE_MAX);
+    off64_t offset = dataProvider.ConsumeIntegralInRange<off64_t>(1, INT64_MAX);
+    bool read_only = dataProvider.ConsumeBool();
+    m.create(orig_name.c_str(), tf.fd, offset, length, read_only);
+    m.getDataOffset();
+    m.getFileName();
+    m.getDataLength();
+    m.getDataPtr();
+    int enum_index = dataProvider.ConsumeIntegral<int>();
+    m.advise(static_cast<android::FileMap::MapAdvice>(enum_index));
+    return 0;
+}