1 //===- FuzzerExtFunctionsDlsym.cpp - Interface to external functions ------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // Implementation for operating systems that support dlsym(). We only use it on 10 // Apple platforms for now. We don't use this approach on Linux because it 11 // requires that clients of LibFuzzer pass ``--export-dynamic`` to the linker. 12 // That is a complication we don't wish to expose to clients right now. 13 //===----------------------------------------------------------------------===// 14 #include "FuzzerInternal.h" 15 #if LIBFUZZER_APPLE 16 17 #include "FuzzerExtFunctions.h" 18 #include <dlfcn.h> 19 20 using namespace fuzzer; 21 22 template <typename T> 23 static 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 38 namespace fuzzer { 39 40 ExternalFunctions::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_FUNC 47 } 48 } // namespace fuzzer 49 #endif // LIBFUZZER_APPLE 50
