LooseFileLoader: Hook extremely early to intercept files

Author: praydog

src/Mods.cpp

@@ -82,7 +82,7 @@ std::optional<std::string> Mods::on_initialize() const {
         }
     }
 
-    utility::Config cfg{ (REFramework::get_persistent_dir() / "re2_fw_config.txt").string() };
+    utility::Config cfg{ (REFramework::get_persistent_dir() / REFrameworkConfig::REFRAMEWORK_CONFIG_NAME).string() };
 
     for (auto& mod : m_mods) {
         spdlog::info("{:s}::on_config_load()", mod->get_name().data());
@@ -96,7 +96,7 @@ std::optional<std::string> Mods::on_initialize() const {
 std::optional<std::string> Mods::on_initialize_d3d_thread() const {
     std::scoped_lock _{g_framework->get_hook_monitor_mutex()};
 
-    utility::Config cfg{ (REFramework::get_persistent_dir() / "re2_fw_config.txt").string() };
+    utility::Config cfg{ (REFramework::get_persistent_dir() / REFrameworkConfig::REFRAMEWORK_CONFIG_NAME).string() };
 
     // once here to at least setup the values
     for (auto& mod : m_mods) {

src/REFramework.cpp

@@ -28,6 +28,7 @@ extern "C" {
 #include "utility/Thread.hpp"
 
 #include "Mods.hpp"
+#include "mods/LooseFileLoader.hpp"
 #include "mods/PluginLoader.hpp"
 #include "sdk/REGlobals.hpp"
 #include "sdk/Application.hpp"
@@ -43,7 +44,6 @@ extern "C" {
 namespace fs = std::filesystem;
 using namespace std::literals;
 
-
 std::unique_ptr<REFramework> g_framework{};
 
 void REFramework::hook_monitor() {
@@ -539,6 +539,20 @@ REFramework::REFramework(HMODULE reframework_module)
     bool found_renderer = false;
     bool renderer_has_render_frame_fn = false;
 
+    if (sdk::RETypeDB::get() != nullptr) {
+        auto& loader = LooseFileLoader::get(); // Initialize this really early
+
+        const auto config_path = get_persistent_dir(REFrameworkConfig::REFRAMEWORK_CONFIG_NAME.data()).string();
+        if (fs::exists(utility::widen(config_path))) {
+            utility::Config cfg{ config_path };
+            loader->on_config_load(cfg);
+        }
+
+        if (loader->is_enabled()) {
+            loader->hook();
+        }
+    }
+
     while (true) try {
         const auto tdb = sdk::RETypeDB::get();
 
@@ -827,7 +841,7 @@ void REFramework::on_frame_d3d11() {
     if (is_init_ok) {
         // Write default config once if it doesn't exist.
         if (!std::exchange(m_created_default_cfg, true)) {
-            if (!fs::exists({utility::widen(get_persistent_dir("re2_fw_config.txt").string())})) {
+            if (!fs::exists({utility::widen(get_persistent_dir(REFrameworkConfig::REFRAMEWORK_CONFIG_NAME.data()).string())})) {
                 save_config();
             }
         }
@@ -932,7 +946,7 @@ void REFramework::on_frame_d3d12() {
     if (is_init_ok) {
         // Write default config once if it doesn't exist.
         if (!std::exchange(m_created_default_cfg, true)) {
-            if (!fs::exists({utility::widen(get_persistent_dir("re2_fw_config.txt").string())})) {
+            if (!fs::exists({utility::widen(get_persistent_dir(REFrameworkConfig::REFRAMEWORK_CONFIG_NAME.data()).string())})) {
                 save_config();
             }
         }
@@ -1313,7 +1327,7 @@ std::filesystem::path REFramework::get_persistent_dir() {
 void REFramework::save_config() {
     std::scoped_lock _{m_config_mtx};
 
-    spdlog::info("Saving config re2_fw_config.txt");
+    spdlog::info("Saving config {}", REFrameworkConfig::REFRAMEWORK_CONFIG_NAME.data());
 
     utility::Config cfg{};
 
@@ -1322,7 +1336,7 @@ void REFramework::save_config() {
     }
 
     try {
-        if (!cfg.save((get_persistent_dir() / "re2_fw_config.txt").string())) {
+        if (!cfg.save((get_persistent_dir() / REFrameworkConfig::REFRAMEWORK_CONFIG_NAME.data()).string())) {
             spdlog::error("Failed to save config");
             return;
         }

src/mods/LooseFileLoader.cpp

@@ -161,30 +161,53 @@ void LooseFileLoader::hook() {
         return;
     }
 
-    auto initial_candidate = [&]() -> std::optional<uintptr_t> {
-        const auto via_io_file = tdb->find_type("via.io.file");
+    auto initial_candidates = [&]() -> std::vector<uintptr_t> {
+        sdk::RETypeDefinition* via_io_file = nullptr;
+
+        // We need to look for via.io.file manually because LooseFileLoader gets loaded extremely early
+        // meaning VM stuff may not work correctly
+        for (auto i = 0; i < tdb->get_num_types(); ++i) {
+            const auto t = tdb->get_type(i);
+
+            if (t == nullptr || t->get_name() == nullptr) {
+                continue;
+            }
+
+            if (std::string_view{t->get_name()} == "file") {
+                if (t->get_declaring_type() != nullptr && std::string_view{t->get_declaring_type()->get_name()} == "io") {
+                    via_io_file = t;
+                    break;
+                }
+            }
+        }
 
         if (via_io_file == nullptr) {
             spdlog::error("[LooseFileLoader] Failed to find via.io.file");
-            return std::nullopt;
+            return {};
         }
 
-        // "exist" and "exists" are 2 different functions. one searches in pak and other doesnt.
-        const auto exists_fn = via_io_file->get_method("exists(System.String)");
+        spdlog::info("[LooseFileLoader] Found via.io.file");
 
-        if (exists_fn == nullptr) {
-            spdlog::error("[LooseFileLoader] Failed to find via.io.file.exists(System.String)");
-            return std::nullopt;
-        }
+        std::vector<uintptr_t> candidates{};
+
+        // Same reason as above, manually loop through methods because VM stuff may not work correctly
+        for (auto& m : via_io_file->get_methods()) {
+            if (m.get_name() == nullptr) {
+                continue;
+            }
 
-        const auto exists_ptr = exists_fn->get_function();
+            if (std::string_view{m.get_name()} == "exists") {
+                if (auto func = m.get_function(); func != nullptr) {
+                    candidates.push_back((uintptr_t)func);
+                }
+            }
+        }
 
-        if (exists_ptr == nullptr) {
-            spdlog::error("[LooseFileLoader] Failed to get function pointer for via.io.file.exists(System.String)");
-            return std::nullopt;
+        if (candidates.empty()) {
+            spdlog::error("[LooseFileLoader] Failed to find via.io.file.exists methods");
         }
 
-        return (uintptr_t)exists_ptr;
+        return candidates;
     }();
 
     const auto game_module = utility::get_executable();
@@ -224,7 +247,7 @@ void LooseFileLoader::hook() {
         });
     };
 
-    if (!initial_candidate) {
+    if (initial_candidates.empty()) {
         // Basically what we're doing here is finding an initial "mov r8d, 800h"
         // and then finding a "mov r8d, 400h" in the function, as well as another "mov r8d, 800h"
         // I call this a landmark scan, where we find a sequence of instructions that are unique to the function
@@ -263,7 +286,13 @@ void LooseFileLoader::hook() {
             }
         }
     } else {
-        check_fn(initial_candidate.value());
+        for (const auto& c : initial_candidates) {
+            check_fn(c);
+
+            if (candidate) {
+                break;
+            }
+        }
     }
 
     if (!candidate) {

src/mods/LooseFileLoader.hpp

@@ -23,8 +23,13 @@ class LooseFileLoader : public Mod {
     void on_frame() override;
     void on_draw_ui() override;
 
-private:
     void hook();
+
+    bool is_enabled() const {
+        return m_enabled->value();
+    }
+
+private:
     bool handle_path(const wchar_t* path, size_t hash);
 
 #if TDB_VER > 67

src/mods/REFrameworkConfig.hpp

@@ -4,6 +4,7 @@
 
 class REFrameworkConfig : public Mod {
 public:
+    static inline constexpr std::string_view REFRAMEWORK_CONFIG_NAME{ "re2_fw_config.txt" };
     static std::shared_ptr<REFrameworkConfig>& get();
 
 public: