fix: support Mod Organizer 2.

When launching with MO2, std::weakly_canonical is not behaving correctly. Security layer is now denying access when / or \ is present in child path, only with MO2.
Only use path from std::directory_iterator entries when listing files. Building a custom path was getting in the way when using MO2.

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Fixed
+- support [MO2](https://github.com/ModOrganizer2/modorganizer/).
 
 ------------------------
 

scripts/RedFileSystem/Test/FileSystemStorageTest.reds

@@ -33,7 +33,7 @@ public class FileSystemStorageTest extends BaseTest {
     let status = this.m_storage.Exists("..\\..\\..\\..\\..\\..\\..\\steam.exe");
 
     this.ExpectString("IsFile denied", s"\(status)", "Denied");
-    let status = this.m_storage.IsFile("test\\");
+    let status = this.m_storage.IsFile("test");
 
     this.ExpectString("IsFile false", s"\(status)", "False");
     let status = this.m_storage.IsFile("test.json");

src/FileSystem.cpp

@@ -10,6 +10,7 @@ RED4ext::Logger* FileSystem::logger = nullptr;
 
 std::filesystem::path FileSystem::game_path;
 std::filesystem::path FileSystem::storages_path;
+bool FileSystem::has_mo2 = false;
 
 std::regex FileSystem::storage_name_rule("[A-Za-z]{3,24}");
 
@@ -20,6 +21,7 @@ void FileSystem::load(RED4ext::PluginHandle p_handle,
                       RED4ext::Logger* p_logger) {
   handle = p_handle;
   logger = p_logger;
+  detect_mo2();
   auto path = std::filesystem::absolute(".");
 
   game_path = path.parent_path().parent_path();
@@ -126,6 +128,10 @@ Red::Handle<FileSystemStorage> FileSystem::get_shared_storage() {
   return storage;
 }
 
+bool FileSystem::is_mo2_detected() {
+  return has_mo2;
+}
+
 bool FileSystem::request_directory(const std::filesystem::path& p_path) {
   std::error_code error;
   bool is_present = std::filesystem::exists(p_path, error);
@@ -137,10 +143,10 @@ bool FileSystem::request_directory(const std::filesystem::path& p_path) {
     return true;
   }
   is_present = std::filesystem::create_directory(p_path, error);
-  if (!is_present || error) {
+  if (error) {
     return false;
   }
-  return true;
+  return is_present;
 }
 
 bool FileSystem::migrate_directory(const std::filesystem::path& p_old_path,
@@ -169,6 +175,14 @@ bool FileSystem::migrate_directory(const std::filesystem::path& p_old_path,
   return true;
 }
 
+void FileSystem::detect_mo2() {
+  has_mo2 = GetModuleHandle(TEXT("usvfs_x64.dll")) != nullptr;
+  if (!has_mo2) {
+    return;
+  }
+  logger->Info(handle, "RedFileSystem launched using MO2.");
+}
+
 Red::Handle<FileSystemStorage> FileSystem::find_storage(
   const std::string& p_name) {
   for (const auto& storage : storages) {

src/FileSystem.h

@@ -24,6 +24,7 @@ class FileSystem : public Red::IScriptable {
 
   static std::filesystem::path game_path;
   static std::filesystem::path storages_path;
+  static bool has_mo2;
 
   static std::regex storage_name_rule;
 
@@ -33,6 +34,7 @@ class FileSystem : public Red::IScriptable {
   static bool request_directory(const std::filesystem::path& p_path);
   static bool migrate_directory(const std::filesystem::path& p_old_path,
                                 const std::filesystem::path& p_new_path);
+  static void detect_mo2();
 
   static Red::Handle<FileSystemStorage> find_storage(const std::string& p_name);
 
@@ -43,6 +45,8 @@ class FileSystem : public Red::IScriptable {
   static Red::Handle<FileSystemStorage> get_storage(const Red::CString& p_name);
   static Red::Handle<FileSystemStorage> get_shared_storage();
 
+  static bool is_mo2_detected();
+
   RTTI_IMPL_TYPEINFO(RedFS::FileSystem);
   RTTI_IMPL_ALLOCATOR();
 };

src/FileSystemStorage.cpp

@@ -1,4 +1,5 @@
 #include "FileSystemStorage.h"
+#include "FileSystem.h"
 
 #include <utility>
 
@@ -82,7 +83,7 @@ Red::DynArray<Red::Handle<File>> FileSystemStorage::get_files() {
   for (const auto& entry : entries) {
     if (entry.is_regular_file()) {
       auto file_name = entry.path().filename();
-      auto file_path = storage_path / file_name;
+      auto file_path = entry.path();
       auto file_mutex = get_mutex(file_path);
       auto file = Red::MakeHandle<File>(file_mutex, file_name, file_path);
 
@@ -123,7 +124,7 @@ Red::DynArray<Red::Handle<AsyncFile>> FileSystemStorage::get_async_files() {
   for (const auto& entry : entries) {
     if (entry.is_regular_file()) {
       auto file_name = entry.path().filename();
-      auto file_path = storage_path / file_name;
+      auto file_path = entry.path();
       auto file_mutex = get_mutex(file_path);
       auto file = Red::MakeHandle<AsyncFile>(file_mutex, file_name, file_path);
 
@@ -136,9 +137,19 @@ Red::DynArray<Red::Handle<AsyncFile>> FileSystemStorage::get_async_files() {
 std::filesystem::path FileSystemStorage::restrict_path(
   const std::string& p_path, std::error_code& p_error) const {
   std::filesystem::path path = storage_path / p_path;
-  std::filesystem::path real_path =
-    std::filesystem::weakly_canonical(path, p_error);
-
+  std::filesystem::path real_path;
+
+  // NOTE: See issue regarding usage of `std::weakly_canonical` with MO2:
+  //       https://github.com/ModOrganizer2/modorganizer/issues/2039
+  if (FileSystem::is_mo2_detected()) {
+    if (p_path.find('/') != std::string::npos ||
+        p_path.find('\\') != std::string::npos) {
+      p_error = std::make_error_code(std::errc::permission_denied);
+    }
+    return path;
+  } else {
+    real_path = std::filesystem::weakly_canonical(path, p_error);
+  }
   if (p_error) {
     return real_path;
   }