Add initial project files (excluding ignored content)

external/safetyhook/example/midhook.cpp

@@ -0,0 +1,65 @@
+#include <print>
+
+#if __has_include("Zydis/Zydis.h")
+#include "Zydis/Zydis.h"
+#elif __has_include("Zydis.h")
+#include "Zydis.h"
+#else
+#error "Zydis not found"
+#endif
+
+#include <safetyhook.hpp>
+
+SAFETYHOOK_NOINLINE int add_42(int a) {
+    return a + 42;
+}
+
+void hooked_add_42(SafetyHookContext& ctx) {
+#if SAFETYHOOK_ARCH_X86_64
+    ctx.rax = 1337;
+#elif SAFETYHOOK_ARCH_X86_32
+    ctx.eax = 1337;
+#endif
+}
+
+SafetyHookMid g_hook{};
+
+int main() {
+    std::println("unhooked add_42(2) = {}", add_42(2));
+
+    // Let's disassemble add_42 and hook its RET.
+    // NOTE: On Linux we should specify -falign-functions=32 to add some padding to the function otherwise we'll
+    // end up hooking the next function's prologue. This is pretty hacky in general but it's just an example.
+    ZydisDecoder decoder{};
+
+#if SAFETYHOOK_ARCH_X86_64
+    ZydisDecoderInit(&decoder, ZYDIS_MACHINE_MODE_LONG_64, ZYDIS_STACK_WIDTH_64);
+#elif SAFETYHOOK_ARCH_X86_32
+    ZydisDecoderInit(&decoder, ZYDIS_MACHINE_MODE_LEGACY_32, ZYDIS_STACK_WIDTH_32);
+#endif
+
+    auto ip = reinterpret_cast<uint8_t*>(add_42);
+
+    while (*ip != 0xC3) {
+        ZydisDecodedInstruction ix{};
+
+        ZydisDecoderDecodeInstruction(&decoder, nullptr, reinterpret_cast<void*>(ip), 15, &ix);
+
+        // Follow JMPs
+        if (ix.opcode == 0xE9) {
+            ip += ix.length + (int32_t)ix.raw.imm[0].value.s;
+        } else {
+            ip += ix.length;
+        }
+    }
+
+    g_hook = safetyhook::create_mid(ip, hooked_add_42);
+
+    std::println("hooked add_42(3) = {}", add_42(3));
+
+    g_hook = {};
+
+    std::println("unhooked add_42(4) = {}", add_42(4));
+
+    return 0;
+}