Feature/VMT hook example (#59)

CMakeLists.txt

@@ -324,6 +324,32 @@ if(SAFETYHOOK_BUILD_EXAMPLES) # build-examples
 		safetyhook::safetyhook
 	)
 
+endif()
+# Target: example-vmthook
+if(SAFETYHOOK_BUILD_EXAMPLES) # build-examples
+	set(example-vmthook_SOURCES
+		"example/vmthook.cpp"
+		cmake.toml
+	)
+
+	add_executable(example-vmthook)
+
+	target_sources(example-vmthook PRIVATE ${example-vmthook_SOURCES})
+	source_group(TREE ${CMAKE_CURRENT_SOURCE_DIR} FILES ${example-vmthook_SOURCES})
+
+	target_compile_features(example-vmthook PRIVATE
+		cxx_std_23
+	)
+
+	target_link_libraries(example-vmthook PRIVATE
+		safetyhook::safetyhook
+	)
+
+	get_directory_property(CMKR_VS_STARTUP_PROJECT DIRECTORY ${PROJECT_SOURCE_DIR} DEFINITION VS_STARTUP_PROJECT)
+	if(NOT CMKR_VS_STARTUP_PROJECT)
+		set_property(DIRECTORY ${PROJECT_SOURCE_DIR} PROPERTY VS_STARTUP_PROJECT example-vmthook)
+	endif()
+
 endif()
 # Target: test
 set(test_SOURCES

cmake.toml

@@ -129,6 +129,10 @@ sources = ["example/threadsafe.cpp"]
 type = "example-dll"
 sources = ["example/dll.cpp"]
 
+[target.example-vmthook]
+type = "example"
+sources = ["example/vmthook.cpp"]
+
 [target.test]
 type = "executable"
 sources = ["test/*.cpp"]

example/midhook.cpp

@@ -1,4 +1,4 @@
-#include <iostream>
+#include <print>
 
 #if __has_include(<Zydis/Zydis.h>)
 #include <Zydis/Zydis.h>
@@ -25,7 +25,7 @@ void hooked_add_42(SafetyHookContext& ctx) {
 SafetyHookMid g_hook{};
 
 int main() {
-    std::cout << add_42(2) << "\n";
+    std::println("unhooked add_42(2) = {}", add_42(2));
 
     // Let's disassemble add_42 and hook its RET.
     ZydisDecoder decoder{};
@@ -55,11 +55,11 @@ int main() {
 
     g_hook = safetyhook::create_mid(ip, hooked_add_42);
 
-    std::cout << add_42(3) << "\n";
+    std::println("hooked add_42(3) = {}", add_42(3));
 
-    g_hook.reset();
+    g_hook = {};
 
-    std::cout << add_42(4) << "\n";
+    std::println("unhooked add_42(4) = {}", add_42(4));
 
     return 0;
 }

example/minimal.cpp

@@ -1,4 +1,4 @@
-#include <iostream>
+#include <print>
 
 #include <safetyhook.hpp>
 
@@ -13,16 +13,16 @@ int hook_add(int x, int y) {
 }
 
 int main() {
-    std::cout << "unhooked add(2, 3) = " << add(2, 3) << "\n";
+    std::println("unhooked add(2, 3) = {}", add(2, 3));
 
     // Create a hook on add.
     g_add_hook = safetyhook::create_inline(reinterpret_cast<void*>(add), reinterpret_cast<void*>(hook_add));
 
-    std::cout << "hooked add(3, 4) = " << add(3, 4) << "\n";
+    std::println("hooked add(3, 4) = {}", add(3, 4));
 
     g_add_hook = {};
 
-    std::cout << "unhooked add(5, 6) = " << add(5, 6) << "\n";
+    std::println("unhooked add(5, 6) = {}", add(5, 6));
 
     return 0;
 }

example/multiple.cpp

@@ -1,11 +1,11 @@
-#include <iostream>
+#include <print>
 
 #include <safetyhook.hpp>
 
 SafetyHookInline hook0, hook1, hook2, hook3;
 
 __declspec(noinline) void say_hi(const std::string& name) {
-    std::cout << "hello " << name << "\n";
+    std::println("hello {}", name);
 }
 
 void hook0_fn(const std::string& name) {

example/threadsafe.cpp

@@ -1,12 +1,12 @@
-#include <iostream>
+#include <print>
 #include <thread>
 
 #include <safetyhook.hpp>
 
 SafetyHookInline g_hook{};
 
 __declspec(noinline) void SayHello(int times) {
-    std::cout << "Hello #" << times << std::endl;
+    std::println("Hello #{}", times);
 }
 
 void Hooked_SayHello(int times [[maybe_unused]]) {

example/vmthook.cpp

@@ -0,0 +1,40 @@
+#include <memory>
+#include <print>
+
+#include <safetyhook.hpp>
+
+class Interface {
+public:
+    virtual ~Interface() = default;
+    virtual int add_42(int a) = 0;
+};
+
+class Target : public Interface {
+public:
+    int add_42(int a) override { return a + 42; }
+};
+
+SafetyHookVmt g_target_hook;
+SafetyHookVm g_add_42_hook;
+
+class Hook : public Target {
+public:
+    int hooked_add_42(int a) { return g_add_42_hook.thiscall<int>(this, a) + 1337; }
+};
+
+int main() {
+    auto target = std::make_unique<Target>();
+
+    std::println("unhooked target->add_42(1) = {}", target->add_42(1));
+
+    g_target_hook = safetyhook::create_vmt(target.get());
+    g_add_42_hook = safetyhook::create_vm(g_target_hook, 1, &Hook::hooked_add_42);
+
+    std::println("hooked target->add_42(2) = {}", target->add_42(1));
+
+    g_target_hook = {};
+
+    std::println("unhooked target->add_42(3) = {}", target->add_42(1));
+
+    return 0;
+}