1*a7c257b0Skamil //===- FuzzerExtFunctionsWeak.cpp - Interface to external functions -------===//
2*a7c257b0Skamil //
3*a7c257b0Skamil // The LLVM Compiler Infrastructure
4*a7c257b0Skamil //
5*a7c257b0Skamil // This file is distributed under the University of Illinois Open Source
6*a7c257b0Skamil // License. See LICENSE.TXT for details.
7*a7c257b0Skamil //
8*a7c257b0Skamil //===----------------------------------------------------------------------===//
9*a7c257b0Skamil // Implementation for Linux. This relies on the linker's support for weak
10*a7c257b0Skamil // symbols. We don't use this approach on Apple platforms because it requires
11*a7c257b0Skamil // clients of LibFuzzer to pass ``-U _<symbol_name>`` to the linker to allow
12*a7c257b0Skamil // weak symbols to be undefined. That is a complication we don't want to expose
13*a7c257b0Skamil // to clients right now.
14*a7c257b0Skamil //===----------------------------------------------------------------------===//
15*a7c257b0Skamil #include "FuzzerDefs.h"
16*a7c257b0Skamil #if LIBFUZZER_LINUX || LIBFUZZER_NETBSD || LIBFUZZER_FUCHSIA || \
17*a7c257b0Skamil LIBFUZZER_FREEBSD || LIBFUZZER_OPENBSD
18*a7c257b0Skamil
19*a7c257b0Skamil #include "FuzzerExtFunctions.h"
20*a7c257b0Skamil #include "FuzzerIO.h"
21*a7c257b0Skamil
22*a7c257b0Skamil extern "C" {
23*a7c257b0Skamil // Declare these symbols as weak to allow them to be optionally defined.
24*a7c257b0Skamil #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \
25*a7c257b0Skamil __attribute__((weak, visibility("default"))) RETURN_TYPE NAME FUNC_SIG
26*a7c257b0Skamil
27*a7c257b0Skamil #include "FuzzerExtFunctions.def"
28*a7c257b0Skamil
29*a7c257b0Skamil #undef EXT_FUNC
30*a7c257b0Skamil }
31*a7c257b0Skamil
32*a7c257b0Skamil using namespace fuzzer;
33*a7c257b0Skamil
CheckFnPtr(void * FnPtr,const char * FnName,bool WarnIfMissing)34*a7c257b0Skamil static void CheckFnPtr(void *FnPtr, const char *FnName, bool WarnIfMissing) {
35*a7c257b0Skamil if (FnPtr == nullptr && WarnIfMissing) {
36*a7c257b0Skamil Printf("WARNING: Failed to find function \"%s\".\n", FnName);
37*a7c257b0Skamil }
38*a7c257b0Skamil }
39*a7c257b0Skamil
40*a7c257b0Skamil namespace fuzzer {
41*a7c257b0Skamil
ExternalFunctions()42*a7c257b0Skamil ExternalFunctions::ExternalFunctions() {
43*a7c257b0Skamil #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \
44*a7c257b0Skamil this->NAME = ::NAME; \
45*a7c257b0Skamil CheckFnPtr(reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(::NAME)), \
46*a7c257b0Skamil #NAME, WARN);
47*a7c257b0Skamil
48*a7c257b0Skamil #include "FuzzerExtFunctions.def"
49*a7c257b0Skamil
50*a7c257b0Skamil #undef EXT_FUNC
51*a7c257b0Skamil }
52*a7c257b0Skamil
53*a7c257b0Skamil } // namespace fuzzer
54*a7c257b0Skamil
55*a7c257b0Skamil #endif
56