compiler-rt/lib/fuzzer/FuzzerInterface.h

   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