| 1 | //===- FuzzerExtFunctionsDlsym.cpp - Interface to external functions ------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // Implementation for operating systems that support dlsym(). We only use it on |
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| 9 | // Apple platforms for now. We don't use this approach on Linux because it |
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| 10 | // requires that clients of LibFuzzer pass ``--export-dynamic`` to the linker. |
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| 11 | // That is a complication we don't wish to expose to clients right now. |
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| 12 | //===----------------------------------------------------------------------===// |
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| 13 | #include "FuzzerPlatform.h" |
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| 14 | #if LIBFUZZER_APPLE |
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| 15 | |
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| 16 | #include "FuzzerExtFunctions.h" |
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| 17 | #include "FuzzerIO.h" |
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| 18 | #include <dlfcn.h> |
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| 19 | |
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| 20 | using namespace fuzzer; |
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| 21 | |
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| 22 | template <typename T> |
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| 23 | static T GetFnPtr(const char *FnName, bool WarnIfMissing) { |
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| 24 | dlerror(); // Clear any previous errors. |
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| 25 | void *Fn = dlsym(RTLD_DEFAULT, FnName); |
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| 26 | if (Fn == nullptr) { |
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| 27 | if (WarnIfMissing) { |
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| 28 | const char *ErrorMsg = dlerror(); |
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| 29 | Printf("WARNING: Failed to find function \"%s\"." , FnName); |
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| 30 | if (ErrorMsg) |
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| 31 | Printf(" Reason %s." , ErrorMsg); |
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| 32 | Printf("\n" ); |
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| 33 | } |
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| 34 | } |
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| 35 | return reinterpret_cast<T>(Fn); |
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| 36 | } |
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| 37 | |
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| 38 | namespace fuzzer { |
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| 39 | |
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| 40 | ExternalFunctions::ExternalFunctions() { |
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| 41 | #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \ |
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| 42 | this->NAME = GetFnPtr<decltype(ExternalFunctions::NAME)>(#NAME, WARN) |
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| 43 | |
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| 44 | #include "FuzzerExtFunctions.def" |
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| 45 | |
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| 46 | #undef EXT_FUNC |
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| 47 | } |
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| 48 | |
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| 49 | } // namespace fuzzer |
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| 50 | |
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| 51 | #endif // LIBFUZZER_APPLE |
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| 52 | |
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