Added some interception macros that work on linux and macos

src/interception.h

@@ -0,0 +1,71 @@
+#pragma once
+
+//==============================================================================
+// The following is extracted from LLVM:
+//==============================================================================
+
+//===-- interception.h ------------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+//
+// Machinery for providing replacements/wrappers for system functions.
+//===----------------------------------------------------------------------===//
+
+#ifdef __linux__
+    #define INTERCEPTOR_ATTRIBUTE
+
+    #define INTERCEPTOR(ret_type, func, ...)        \
+    extern "C" INTERCEPTOR_ATTRIBUTE ret_type func(__VA_ARGS__)
+
+    #define INTERCEPT_FUNCTION(ret_type, func, ...) static auto real = (ret_type (*)(__VA_ARGS__))dlsym(RTLD_NEXT, #func);
+
+    #define REAL(func, ...) real __VA_ARGS__
+#elif __APPLE__
+    using uptr      = size_t;
+
+    struct interpose_substitution {
+        const uptr replacement;
+        const uptr original;
+    };
+
+    // For a function foo() create a global pair of pointers { wrap_foo, foo } in
+    // the __DATA,__interpose section.
+    // As a result all the calls to foo() will be routed to wrap_foo() at runtime.
+    #define INTERPOSER(func_name) __attribute__((used))     \
+    const interpose_substitution substitution_##func_name[] \
+    __attribute__((section("__DATA, __interpose"))) = { \
+    { reinterpret_cast<const uptr>(WRAP(func_name)),    \
+    reinterpret_cast<const uptr>(func_name) }         \
+    }
+
+    #define WRAP(x) wrap_##x
+    #define TRAMPOLINE(x) WRAP(x)
+    #define INTERCEPTOR_ATTRIBUTE
+    #define DECLARE_WRAPPER(ret_type, func, ...)
+
+    // #define REAL(func, ...) WRAP(func) (__VA_ARGS__)
+    #define REAL(x) x
+    #define DECLARE_REAL(ret_type, func, ...) \
+    extern "C" ret_type func(__VA_ARGS__);
+    #define ASSIGN_REAL(x, y)
+
+    #define INTERCEPTOR_ZZZ(suffix, ret_type, func, ...)  \
+    extern "C" ret_type func(__VA_ARGS__) suffix;       \
+    extern "C" ret_type WRAP(func)(__VA_ARGS__);        \
+    INTERPOSER(func);                                   \
+    extern "C" INTERCEPTOR_ATTRIBUTE ret_type WRAP(func)(__VA_ARGS__)
+
+    #define INTERCEPTOR(ret_type, func, ...) \
+    INTERCEPTOR_ZZZ(/*no symbol variants*/, ret_type, func, __VA_ARGS__)
+
+    #define INTERCEPTOR_WITH_SUFFIX(ret_type, func, ...) \
+    INTERCEPTOR_ZZZ(__DARWIN_ALIAS_C(func), ret_type, func, __VA_ARGS__)
+
+    #define INTERCEPT_FUNCTION(...)
+#endif