1 //===- FuzzerInterface.h - Interface header for the Fuzzer ------*- C++ -* ===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
9 // Define the interface between the Fuzzer and the library being tested.
10 //===----------------------------------------------------------------------===//
12 // WARNING: keep the interface free of STL or any other header-based C++ lib,
13 // to avoid bad interactions between the code used in the fuzzer and
14 // the code used in the target function.
16 #ifndef LLVM_FUZZER_INTERFACE_H
17 #define LLVM_FUZZER_INTERFACE_H
24 typedef void (*UserCallback)(const uint8_t *Data, size_t Size);
25 /** Simple C-like interface with a single user-supplied callback.
30 #include "FuzzerInterface.h"
32 void LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
33 DoStuffWithData(Data, Size);
36 // Implement your own main() or use the one from FuzzerMain.cpp.
37 int main(int argc, char **argv) {
38 InitializeMeIfNeeded();
39 return fuzzer::FuzzerDriver(argc, argv, LLVMFuzzerTestOneInput);
43 int FuzzerDriver(int argc, char **argv, UserCallback Callback);
45 class FuzzerRandomBase {
48 virtual ~FuzzerRandomBase(){};
49 virtual void ResetSeed(int seed) = 0;
50 // Return a random number.
51 virtual size_t Rand() = 0;
52 // Return a random number in range [0,n).
53 size_t operator()(size_t n) { return Rand() % n; }
54 bool RandBool() { return Rand() % 2; }
57 class FuzzerRandomLibc : public FuzzerRandomBase {
59 FuzzerRandomLibc(int seed) { ResetSeed(seed); }
60 void ResetSeed(int seed) override;
61 ~FuzzerRandomLibc() override {}
62 size_t Rand() override;
65 /** An abstract class that allows to use user-supplied mutators with libFuzzer.
70 #include "FuzzerInterface.h"
71 class MyFuzzer : public fuzzer::UserSuppliedFuzzer {
73 MyFuzzer(fuzzer::FuzzerRandomBase *Rand);
74 // Must define the target function.
75 void TargetFunction(...) { ... }
76 // Optionally define the mutator.
77 size_t Mutate(...) { ... }
78 // Optionally define the CrossOver method.
79 size_t CrossOver(...) { ... }
82 int main(int argc, char **argv) {
84 fuzzer::FuzzerDriver(argc, argv, F);
88 class UserSuppliedFuzzer {
90 UserSuppliedFuzzer(); // Deprecated, don't use.
91 UserSuppliedFuzzer(FuzzerRandomBase *Rand);
92 /// Executes the target function on 'Size' bytes of 'Data'.
93 virtual void TargetFunction(const uint8_t *Data, size_t Size) = 0;
94 /// Mutates 'Size' bytes of data in 'Data' inplace into up to 'MaxSize' bytes,
95 /// returns the new size of the data, which should be positive.
96 virtual size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
97 return BasicMutate(Data, Size, MaxSize);
99 /// Crosses 'Data1' and 'Data2', writes up to 'MaxOutSize' bytes into Out,
100 /// returns the number of bytes written, which should be positive.
101 virtual size_t CrossOver(const uint8_t *Data1, size_t Size1,
102 const uint8_t *Data2, size_t Size2,
103 uint8_t *Out, size_t MaxOutSize) {
104 return BasicCrossOver(Data1, Size1, Data2, Size2, Out, MaxOutSize);
106 virtual ~UserSuppliedFuzzer();
108 FuzzerRandomBase &GetRand() { return *Rand; }
111 /// These can be called internally by Mutate and CrossOver.
112 size_t BasicMutate(uint8_t *Data, size_t Size, size_t MaxSize);
113 size_t BasicCrossOver(const uint8_t *Data1, size_t Size1,
114 const uint8_t *Data2, size_t Size2,
115 uint8_t *Out, size_t MaxOutSize);
117 bool OwnRand = false;
118 FuzzerRandomBase *Rand;
121 /// Runs the fuzzing with the UserSuppliedFuzzer.
122 int FuzzerDriver(int argc, char **argv, UserSuppliedFuzzer &USF);
124 } // namespace fuzzer
126 #endif // LLVM_FUZZER_INTERFACE_H