1*0b57cec5SDimitry Andric //===- FuzzerExtFunctionsWeak.cpp - Interface to external functions -------===// 2*0b57cec5SDimitry Andric // 3*0b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*0b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*0b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*0b57cec5SDimitry Andric // 7*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 8*0b57cec5SDimitry Andric // Implementation for Linux. This relies on the linker's support for weak 9*0b57cec5SDimitry Andric // symbols. We don't use this approach on Apple platforms because it requires 10*0b57cec5SDimitry Andric // clients of LibFuzzer to pass ``-U _<symbol_name>`` to the linker to allow 11*0b57cec5SDimitry Andric // weak symbols to be undefined. That is a complication we don't want to expose 12*0b57cec5SDimitry Andric // to clients right now. 13*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 14*0b57cec5SDimitry Andric #include "FuzzerDefs.h" 15*0b57cec5SDimitry Andric #if LIBFUZZER_LINUX || LIBFUZZER_NETBSD || LIBFUZZER_FUCHSIA || \ 16*0b57cec5SDimitry Andric LIBFUZZER_FREEBSD || LIBFUZZER_OPENBSD 17*0b57cec5SDimitry Andric 18*0b57cec5SDimitry Andric #include "FuzzerExtFunctions.h" 19*0b57cec5SDimitry Andric #include "FuzzerIO.h" 20*0b57cec5SDimitry Andric 21*0b57cec5SDimitry Andric extern "C" { 22*0b57cec5SDimitry Andric // Declare these symbols as weak to allow them to be optionally defined. 23*0b57cec5SDimitry Andric #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \ 24*0b57cec5SDimitry Andric __attribute__((weak, visibility("default"))) RETURN_TYPE NAME FUNC_SIG 25*0b57cec5SDimitry Andric 26*0b57cec5SDimitry Andric #include "FuzzerExtFunctions.def" 27*0b57cec5SDimitry Andric 28*0b57cec5SDimitry Andric #undef EXT_FUNC 29*0b57cec5SDimitry Andric } 30*0b57cec5SDimitry Andric 31*0b57cec5SDimitry Andric using namespace fuzzer; 32*0b57cec5SDimitry Andric 33*0b57cec5SDimitry Andric static void CheckFnPtr(void *FnPtr, const char *FnName, bool WarnIfMissing) { 34*0b57cec5SDimitry Andric if (FnPtr == nullptr && WarnIfMissing) { 35*0b57cec5SDimitry Andric Printf("WARNING: Failed to find function \"%s\".\n", FnName); 36*0b57cec5SDimitry Andric } 37*0b57cec5SDimitry Andric } 38*0b57cec5SDimitry Andric 39*0b57cec5SDimitry Andric namespace fuzzer { 40*0b57cec5SDimitry Andric 41*0b57cec5SDimitry Andric ExternalFunctions::ExternalFunctions() { 42*0b57cec5SDimitry Andric #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \ 43*0b57cec5SDimitry Andric this->NAME = ::NAME; \ 44*0b57cec5SDimitry Andric CheckFnPtr(reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(::NAME)), \ 45*0b57cec5SDimitry Andric #NAME, WARN); 46*0b57cec5SDimitry Andric 47*0b57cec5SDimitry Andric #include "FuzzerExtFunctions.def" 48*0b57cec5SDimitry Andric 49*0b57cec5SDimitry Andric #undef EXT_FUNC 50*0b57cec5SDimitry Andric } 51*0b57cec5SDimitry Andric 52*0b57cec5SDimitry Andric } // namespace fuzzer 53*0b57cec5SDimitry Andric 54*0b57cec5SDimitry Andric #endif 55