george.karpenkov | 29efa6d | 2017-08-21 23:25:50 +0000 | [diff] [blame] | 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 | |
| 41 | ExternalFunctions::ExternalFunctions() { |
| 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 |