LLVM  6.0.0svn
FuzzerExtFunctionsDlsym.cpp
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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 "FuzzerDefs.h"
15 #if LIBFUZZER_APPLE
16 
17 #include "FuzzerExtFunctions.h"
18 #include "FuzzerIO.h"
19 #include <dlfcn.h>
20 
21 using namespace fuzzer;
22 
23 template <typename T>
24 static T GetFnPtr(const char *FnName, bool WarnIfMissing) {
25  dlerror(); // Clear any previous errors.
26  void *Fn = dlsym(RTLD_DEFAULT, FnName);
27  if (Fn == nullptr) {
28  if (WarnIfMissing) {
29  const char *ErrorMsg = dlerror();
30  Printf("WARNING: Failed to find function \"%s\".", FnName);
31  if (ErrorMsg)
32  Printf(" Reason %s.", ErrorMsg);
33  Printf("\n");
34  }
35  }
36  return reinterpret_cast<T>(Fn);
37 }
38 
39 namespace fuzzer {
40 
42 #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \
43  this->NAME = GetFnPtr<decltype(ExternalFunctions::NAME)>(#NAME, WARN)
44 
45 #include "FuzzerExtFunctions.def"
46 
47 #undef EXT_FUNC
48 }
49 
50 } // namespace fuzzer
51 
52 #endif // LIBFUZZER_APPLE
void Printf(const char *Fmt,...)
Definition: FuzzerIO.cpp:112