52 lines · cpp
1//===- FuzzerExtFunctionsDlsym.cpp - Interface to external functions ------===//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-exception6//7//===----------------------------------------------------------------------===//8// Implementation for operating systems that support dlsym(). We only use it on9// Apple platforms for now. We don't use this approach on Linux because it10// requires that clients of LibFuzzer pass ``--export-dynamic`` to the linker.11// That is a complication we don't wish to expose to clients right now.12//===----------------------------------------------------------------------===//13#include "FuzzerPlatform.h"14#if LIBFUZZER_APPLE15 16#include "FuzzerExtFunctions.h"17#include "FuzzerIO.h"18#include <dlfcn.h>19 20using namespace fuzzer;21 22template <typename T>23static T GetFnPtr(const char *FnName, bool WarnIfMissing) {24 dlerror(); // Clear any previous errors.25 void *Fn = dlsym(RTLD_DEFAULT, FnName);26 if (Fn == nullptr) {27 if (WarnIfMissing) {28 const char *ErrorMsg = dlerror();29 Printf("WARNING: Failed to find function \"%s\".", FnName);30 if (ErrorMsg)31 Printf(" Reason %s.", ErrorMsg);32 Printf("\n");33 }34 }35 return reinterpret_cast<T>(Fn);36}37 38namespace fuzzer {39 40ExternalFunctions::ExternalFunctions() {41#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \42 this->NAME = GetFnPtr<decltype(ExternalFunctions::NAME)>(#NAME, WARN)43 44#include "FuzzerExtFunctions.def"45 46#undef EXT_FUNC47}48 49} // namespace fuzzer50 51#endif // LIBFUZZER_APPLE52