1 //===- FuzzerExtFunctionsWeak.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 Linux. This relies on the linker's support for weak 10 // symbols. We don't use this approach on Apple platforms because it requires 11 // clients of LibFuzzer to pass ``-U _<symbol_name>`` to the linker to allow 12 // weak symbols to be undefined. That is a complication we don't want to expose 13 // to clients right now. 14 //===----------------------------------------------------------------------===// 15 #include "FuzzerDefs.h" 16 #if LIBFUZZER_LINUX || LIBFUZZER_NETBSD || LIBFUZZER_FUCHSIA || \ 17 LIBFUZZER_FREEBSD || LIBFUZZER_OPENBSD 18 19 #include "FuzzerExtFunctions.h" 20 #include "FuzzerIO.h" 21 22 extern "C" { 23 // Declare these symbols as weak to allow them to be optionally defined. 24 #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \ 25 __attribute__((weak, visibility("default"))) RETURN_TYPE NAME FUNC_SIG 26 27 #include "FuzzerExtFunctions.def" 28 29 #undef EXT_FUNC 30 } 31 32 using namespace fuzzer; 33 34 static void CheckFnPtr(void *FnPtr, const char *FnName, bool WarnIfMissing) { 35 if (FnPtr == nullptr && WarnIfMissing) { 36 Printf("WARNING: Failed to find function \"%s\".\n", FnName); 37 } 38 } 39 40 namespace fuzzer { 41 42 ExternalFunctions::ExternalFunctions() { 43 #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \ 44 this->NAME = ::NAME; \ 45 CheckFnPtr(reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(::NAME)), \ 46 #NAME, WARN); 47 48 #include "FuzzerExtFunctions.def" 49 50 #undef EXT_FUNC 51 } 52 53 } // namespace fuzzer 54 55 #endif 56
Indexes created Sat Sep 20 22:09:52 GMT 2025