1 //===- FuzzerInterface.h - Interface header for the Fuzzer ------*- C++ -* ===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // Define the interface between libFuzzer and the library being tested. 9 //===----------------------------------------------------------------------===// 10 11 // NOTE: the libFuzzer interface is thin and in the majority of cases 12 // you should not include this file into your target. In 95% of cases 13 // all you need is to define the following function in your file: 14 // extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size); 15 16 // WARNING: keep the interface in C. 17 18 #ifndef LLVM_FUZZER_INTERFACE_H 19 #define LLVM_FUZZER_INTERFACE_H 20 21 #include <stddef.h> 22 #include <stdint.h> 23 24 #ifdef __cplusplus 25 extern "C" { 26 #endif // __cplusplus 27 28 // Define FUZZER_INTERFACE_VISIBILITY to set default visibility in a way that 29 // doesn't break MSVC. 30 #if defined(_WIN32) 31 #define FUZZER_INTERFACE_VISIBILITY __declspec(dllexport) 32 #else 33 #define FUZZER_INTERFACE_VISIBILITY __attribute__((visibility("default"))) 34 #endif 35 36 // Mandatory user-provided target function. 37 // Executes the code under test with [Data, Data+Size) as the input. 38 // libFuzzer will invoke this function *many* times with different inputs. 39 // Must return 0. 40 FUZZER_INTERFACE_VISIBILITY int 41 LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size); 42 43 // Optional user-provided initialization function. 44 // If provided, this function will be called by libFuzzer once at startup. 45 // It may read and modify argc/argv. 46 // Must return 0. 47 FUZZER_INTERFACE_VISIBILITY int LLVMFuzzerInitialize(int *argc, char ***argv); 48 49 // Optional user-provided custom mutator. 50 // Mutates raw data in [Data, Data+Size) inplace. 51 // Returns the new size, which is not greater than MaxSize. 52 // Given the same Seed produces the same mutation. 53 FUZZER_INTERFACE_VISIBILITY size_t 54 LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size, size_t MaxSize, 55 unsigned int Seed); 56 57 // Optional user-provided custom cross-over function. 58 // Combines pieces of Data1 & Data2 together into Out. 59 // Returns the new size, which is not greater than MaxOutSize. 60 // Should produce the same mutation given the same Seed. 61 FUZZER_INTERFACE_VISIBILITY size_t 62 LLVMFuzzerCustomCrossOver(const uint8_t *Data1, size_t Size1, 63 const uint8_t *Data2, size_t Size2, uint8_t *Out, 64 size_t MaxOutSize, unsigned int Seed); 65 66 // Experimental, may go away in future. 67 // libFuzzer-provided function to be used inside LLVMFuzzerCustomMutator. 68 // Mutates raw data in [Data, Data+Size) inplace. 69 // Returns the new size, which is not greater than MaxSize. 70 FUZZER_INTERFACE_VISIBILITY size_t 71 LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize); 72 73 #undef FUZZER_INTERFACE_VISIBILITY 74 75 #ifdef __cplusplus 76 } // extern "C" 77 #endif // __cplusplus 78 79 #endif // LLVM_FUZZER_INTERFACE_H 80