[libFuzzer] add MagicSeparatorTest
llvm-svn: 359620
diff --git a/compiler-rt/test/fuzzer/MagicSeparatorTest.cpp b/compiler-rt/test/fuzzer/MagicSeparatorTest.cpp
new file mode 100644
index 0000000..2c0fbc9
--- /dev/null
+++ b/compiler-rt/test/fuzzer/MagicSeparatorTest.cpp
@@ -0,0 +1,49 @@
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// Simple test for a fuzzer.
+// This is a sample fuzz target for a custom serialization format that uses
+// a magic separator to split the input into several independent buffers.
+// The fuzzer must find the input consisting of 2 subinputs: "Fuzz" and "me".
+#include <cassert>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+#include <algorithm>
+#include <vector>
+
+// Splits [data,data+size) into a vector of strings using a "magic" Separator.
+std::vector<std::vector<uint8_t>> SplitInput(const uint8_t *Data, size_t Size,
+ const uint8_t *Separator,
+ size_t SeparatorSize) {
+ std::vector<std::vector<uint8_t>> Res;
+ assert(SeparatorSize > 0);
+ auto Beg = Data;
+ auto End = Data + Size;
+ // Using memmem here. std::search may be harder for libFuzzer today.
+ while (const uint8_t *Pos = (const uint8_t *)memmem(Beg, End - Beg,
+ Separator, SeparatorSize)) {
+ Res.push_back({Beg, Pos});
+ Beg = Pos + SeparatorSize;
+ }
+ if (Beg < End)
+ Res.push_back({Beg, End});
+ return Res;
+}
+
+static volatile int *Nil = nullptr;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+ if (Size > 10) return 0; // To make the test quick.
+ const uint8_t Separator[] = {0xDE, 0xAD, 0xBE, 0xEF};
+ auto Inputs = SplitInput(Data, Size, Separator, sizeof(Separator));
+ std::vector<uint8_t> Fuzz({'F', 'u', 'z', 'z'});
+ std::vector<uint8_t> Me({'m', 'e'});
+ if (Inputs.size() == 2 && Inputs[0] == Fuzz && Inputs[1] == Me)
+ *Nil = 42; // crash.
+ return 0;
+}
+