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-rw-r--r--tools/fuzzing/libfuzzer/FuzzerExtFunctionsDlsym.cpp51
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diff --git a/tools/fuzzing/libfuzzer/FuzzerExtFunctionsDlsym.cpp b/tools/fuzzing/libfuzzer/FuzzerExtFunctionsDlsym.cpp
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+++ b/tools/fuzzing/libfuzzer/FuzzerExtFunctionsDlsym.cpp
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+//===- FuzzerExtFunctionsDlsym.cpp - Interface to external functions ------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// Implementation for operating systems that support dlsym(). We only use it on
+// Apple platforms for now. We don't use this approach on Linux because it
+// requires that clients of LibFuzzer pass ``--export-dynamic`` to the linker.
+// That is a complication we don't wish to expose to clients right now.
+//===----------------------------------------------------------------------===//
+#include "FuzzerPlatform.h"
+#if LIBFUZZER_APPLE
+
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+#include <dlfcn.h>
+
+using namespace fuzzer;
+
+template <typename T>
+static T GetFnPtr(const char *FnName, bool WarnIfMissing) {
+ dlerror(); // Clear any previous errors.
+ void *Fn = dlsym(RTLD_DEFAULT, FnName);
+ if (Fn == nullptr) {
+ if (WarnIfMissing) {
+ const char *ErrorMsg = dlerror();
+ Printf("WARNING: Failed to find function \"%s\".", FnName);
+ if (ErrorMsg)
+ Printf(" Reason %s.", ErrorMsg);
+ Printf("\n");
+ }
+ }
+ return reinterpret_cast<T>(Fn);
+}
+
+namespace fuzzer {
+
+ExternalFunctions::ExternalFunctions() {
+#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \
+ this->NAME = GetFnPtr<decltype(ExternalFunctions::NAME)>(#NAME, WARN)
+
+#include "FuzzerExtFunctions.def"
+
+#undef EXT_FUNC
+}
+
+} // namespace fuzzer
+
+#endif // LIBFUZZER_APPLE