ams_mitm: Implement savedata redirection

stratosphere/ams_mitm/source/fs_mitm/fs_mitm_service.cpp

@@ -18,6 +18,7 @@
 #include "fs_mitm_service.hpp"
 #include "fsmitm_boot0storage.hpp"
 #include "fsmitm_layered_romfs_storage.hpp"
+#include "fsmitm_save_utils.hpp"
 
 namespace ams::mitm::fs {
 
@@ -78,6 +79,70 @@ namespace ams::mitm::fs {
         return ResultSuccess();
     }
 
+    Result FsMitmService::OpenSaveDataFileSystem(sf::Out<std::shared_ptr<IFileSystemInterface>> out, u8 _space_id, const FsSaveDataAttribute &attribute) {
+        /* We only want to intercept saves for games, right now. */
+        const bool is_game_or_hbl = this->client_info.override_status.IsHbl() || ncm::IsApplicationProgramId(this->client_info.program_id);
+        R_UNLESS(is_game_or_hbl, sm::mitm::ResultShouldForwardToSession());
+
+        /* Only redirect if the appropriate system setting is set. */
+        R_UNLESS(GetSettingsItemBooleanValue("atmosphere", "fsmitm_redirect_saves_to_sd"), sm::mitm::ResultShouldForwardToSession());
+
+        /* Only redirect if the specific title being accessed has a redirect save flag. */
+        R_UNLESS(cfg::HasContentSpecificFlag(this->client_info.program_id, "redirect_save"), sm::mitm::ResultShouldForwardToSession());
+
+        /* Only redirect account savedata. */
+        R_UNLESS(attribute.save_data_type == FsSaveDataType_Account, sm::mitm::ResultShouldForwardToSession());
+
+        /* Get enum type for space id. */
+        auto space_id = static_cast<FsSaveDataSpaceId>(_space_id);
+
+        /* Verify we can open the save. */
+        FsFileSystem save_fs;
+        R_UNLESS(R_SUCCEEDED(fsOpenSaveDataFileSystemFwd(this->forward_service.get(), &save_fs, space_id, &attribute)), sm::mitm::ResultShouldForwardToSession());
+        const sf::cmif::DomainObjectId target_object_id{serviceGetObjectId(&save_fs.s)};
+        std::unique_ptr<fs::fsa::IFileSystem> save_ifs = std::make_unique<fs::RemoteFileSystem>(save_fs);
+
+        /* Mount the SD card using fs.mitm's session. */
+        FsFileSystem sd_fs;
+        R_TRY(fsOpenSdCardFileSystem(&sd_fs));
+        std::shared_ptr<fs::fsa::IFileSystem> sd_ifs = std::make_shared<fs::RemoteFileSystem>(sd_fs);
+
+        /* Verify that we can open the save directory, and that it exists. */
+        const ncm::ProgramId application_id = attribute.application_id == 0 ? this->client_info.program_id : ncm::ProgramId{attribute.application_id};
+        char save_dir_path[fs::EntryNameLengthMax + 1];
+        R_TRY(mitm::fs::SaveUtil::GetDirectorySaveDataPath(save_dir_path, sizeof(save_dir_path), application_id, space_id, attribute));
+
+        /* Check if this is the first time we're making the save. */
+        bool is_new_save = false;
+        {
+            fs::DirectoryEntryType ent;
+            R_TRY_CATCH(sd_ifs->GetEntryType(&ent, save_dir_path)) {
+                R_CATCH(fs::ResultPathNotFound) { is_new_save = true; }
+                R_CATCH_ALL() { /* ... */ }
+            } R_END_TRY_CATCH;
+        }
+
+        /* Ensure the directory exists. */
+        R_TRY(fssystem::EnsureDirectoryExistsRecursively(sd_ifs.get(), save_dir_path));
+
+        /* Create directory savedata filesystem. */
+        std::unique_ptr<fs::fsa::IFileSystem> subdir_fs = std::make_unique<fssystem::SubDirectoryFileSystem>(sd_ifs, save_dir_path);
+        std::shared_ptr<fssystem::DirectorySaveDataFileSystem> dirsave_ifs = std::make_shared<fssystem::DirectorySaveDataFileSystem>(std::move(subdir_fs));
+
+        /* Ensure correct directory savedata filesystem state. */
+        R_TRY(dirsave_ifs->Initialize());
+
+        /* If it's the first time we're making the save, copy existing savedata over. */
+        if (is_new_save) {
+            /* TODO: Check error? */
+            dirsave_ifs->CopySaveFromFileSystem(save_ifs.get());
+        }
+
+        /* Set output. */
+        out.SetValue(std::make_shared<IFileSystemInterface>(std::move(dirsave_ifs), false), target_object_id);
+        return ResultSuccess();
+    }
+
     Result FsMitmService::OpenBisStorage(sf::Out<std::shared_ptr<IStorageInterface>> out, u32 _bis_partition_id) {
         const ::FsBisPartitionId bis_partition_id = static_cast<::FsBisPartitionId>(_bis_partition_id);
 

stratosphere/ams_mitm/source/fs_mitm/fs_mitm_service.hpp

@@ -63,7 +63,7 @@ namespace ams::mitm::fs {
             /* Result OpenFileSystemWithPatch(Out<std::shared_ptr<IFileSystemInterface>> out, u64 program_id, u32 filesystem_type); */
             /* Result OpenFileSystemWithId(Out<std::shared_ptr<IFileSystemInterface>> out, InPointer<char> path, u64 program_id, u32 filesystem_type); */
             Result OpenSdCardFileSystem(sf::Out<std::shared_ptr<IFileSystemInterface>> out);
-            /* Result OpenSaveDataFileSystem(Out<std::shared_ptr<IFileSystemInterface>> out, u8 space_id, FsSave save_struct); */
+            Result OpenSaveDataFileSystem(sf::Out<std::shared_ptr<IFileSystemInterface>> out, u8 space_id, const FsSaveDataAttribute &attribute);
             Result OpenBisStorage(sf::Out<std::shared_ptr<IStorageInterface>> out, u32 bis_partition_id);
             Result OpenDataStorageByCurrentProcess(sf::Out<std::shared_ptr<IStorageInterface>> out);
             Result OpenDataStorageByDataId(sf::Out<std::shared_ptr<IStorageInterface>> out, ncm::ProgramId /* TODO: ncm::DataId */ data_id, u8 storage_id);
@@ -72,7 +72,7 @@ namespace ams::mitm::fs {
                 /* MAKE_SERVICE_COMMAND_META(OpenFileSystemWithPatch, hos::Version_200), */
                 /* MAKE_SERVICE_COMMAND_META(OpenFileSystemWithId,    hos::Version_200), */
                 MAKE_SERVICE_COMMAND_META(OpenSdCardFileSystem),
-                /* MAKE_SERVICE_COMMAND_META(OpenSaveDataFileSystem), */
+                MAKE_SERVICE_COMMAND_META(OpenSaveDataFileSystem),
                 MAKE_SERVICE_COMMAND_META(OpenBisStorage),
                 MAKE_SERVICE_COMMAND_META(OpenDataStorageByCurrentProcess),
                 MAKE_SERVICE_COMMAND_META(OpenDataStorageByDataId),

stratosphere/ams_mitm/source/fs_mitm/fs_shim.c

@@ -50,3 +50,16 @@ Result fsOpenDataStorageByDataIdFwd(Service* s, FsStorage* out, u64 data_id, Ncm
         .out_objects = &out->s,
     );
 }
+
+Result fsOpenSaveDataFileSystemFwd(Service* s, FsFileSystem* out, FsSaveDataSpaceId save_data_space_id, const FsSaveDataAttribute *attr) {
+    const struct {
+        u8 save_data_space_id;
+        u8 pad[7];
+        FsSaveDataAttribute attr;
+    } in = { (u8)save_data_space_id, {0}, *attr };
+
+    return serviceDispatchIn(s, 51, in,
+        .out_num_objects = 1,
+        .out_objects = &out->s,
+    );
+}

stratosphere/ams_mitm/source/fs_mitm/fs_shim.h

@@ -17,6 +17,8 @@ Result fsOpenBisStorageFwd(Service* s, FsStorage* out, FsBisPartitionId partitio
 Result fsOpenDataStorageByCurrentProcessFwd(Service* s, FsStorage* out);
 Result fsOpenDataStorageByDataIdFwd(Service* s, FsStorage* out, u64 data_id, NcmStorageId storage_id);
 
+Result fsOpenSaveDataFileSystemFwd(Service* s, FsFileSystem* out, FsSaveDataSpaceId save_data_space_id, const FsSaveDataAttribute *attr);
+
 
 #ifdef __cplusplus
 }

stratosphere/ams_mitm/source/fs_mitm/fsmitm_save_utils.cpp

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2018-2019 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "fsmitm_save_utils.hpp"
+
+namespace ams::mitm::fs {
+
+    using namespace ams::fs;
+
+    namespace {
+
+        Result GetSaveDataSpaceIdString(const char **out_str, u8 space_id) {
+            switch (space_id) {
+                case FsSaveDataSpaceId_System:
+                case FsSaveDataSpaceId_ProperSystem:
+                    *out_str = "sys";
+                    break;
+                case FsSaveDataSpaceId_User:
+                    *out_str = "user";
+                    break;
+                case FsSaveDataSpaceId_SdSystem:
+                    *out_str = "sd_sys";
+                    break;
+                case FsSaveDataSpaceId_Temporary:
+                    *out_str = "temp";
+                    break;
+                case FsSaveDataSpaceId_SdUser:
+                    *out_str = "sd_user";
+                    break;
+                case FsSaveDataSpaceId_SafeMode:
+                    *out_str = "safe";
+                    break;
+                default:
+                    return fs::ResultInvalidSaveDataSpaceId();
+            }
+
+            return ResultSuccess();
+        }
+
+        Result GetSaveDataTypeString(const char **out_str, u8 save_data_type) {
+            switch (save_data_type) {
+                case FsSaveDataType_System:
+                    *out_str = "system";
+                    break;
+                case FsSaveDataType_Account:
+                    *out_str = "account";
+                    break;
+                case FsSaveDataType_Bcat:
+                    *out_str = "bcat";
+                    break;
+                case FsSaveDataType_Device:
+                    *out_str = "device";
+                    break;
+                case FsSaveDataType_Temporary:
+                    *out_str = "temp";
+                    break;
+                case FsSaveDataType_Cache:
+                    *out_str = "cache";
+                    break;
+                case FsSaveDataType_SystemBcat:
+                    *out_str = "system_bcat";
+                    break;
+                default:
+                    /* TODO: Better result? */
+                    return fs::ResultInvalidArgument();
+            }
+
+            return ResultSuccess();
+        }
+
+        constexpr inline bool IsEmptyAccountId(const AccountUid &uid) {
+            constexpr AccountUid empty_uid = {};
+            return std::memcmp(&uid, &empty_uid, sizeof(uid)) == 0;
+        }
+
+
+    }
+
+    Result SaveUtil::GetDirectorySaveDataPath(char *dst, size_t dst_size, ncm::ProgramId program_id, u8 space_id, const FsSaveDataAttribute &attribute) {
+        /* Saves should be separate for emunand vs sysnand. */
+        const char *emummc_str = emummc::IsActive() ? "emummc" : "sysmmc";
+
+        /* Get space_id, save_data_type strings. */
+        const char *space_id_str, *save_type_str;
+        R_TRY(GetSaveDataSpaceIdString(&space_id_str, space_id));
+        R_TRY(GetSaveDataTypeString(&save_type_str, attribute.save_data_type));
+
+        /* Initialize the path. */
+        const bool is_system = attribute.system_save_data_id != 0 && IsEmptyAccountId(attribute.uid);
+        size_t out_path_len;
+        if (is_system) {
+            out_path_len = static_cast<size_t>(std::snprintf(dst, dst_size, "/atmosphere/saves/%s/%s/%s/%016lx", emummc_str, space_id_str, save_type_str, attribute.system_save_data_id));
+        } else {
+            out_path_len = static_cast<size_t>(std::snprintf(dst, dst_size, "/atmosphere/saves/%s/%s/%s/%016lx/%016lx%016lx", emummc_str, space_id_str, save_type_str, static_cast<u64>(program_id), attribute.uid.uid[1], attribute.uid.uid[0]));
+        }
+
+        R_UNLESS(out_path_len < dst_size, fs::ResultTooLongPath());
+
+        return ResultSuccess();
+    }
+
+}

stratosphere/ams_mitm/source/fs_mitm/fsmitm_save_utils.hpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2018-2019 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+
+namespace ams::mitm::fs {
+
+    class SaveUtil {
+        public:
+            static Result GetDirectorySaveDataPath(char *dst, size_t dst_size, ncm::ProgramId program_id, u8 space_id, const FsSaveDataAttribute &attribute);
+    };
+
+}

stratosphere/libstratosphere/include/stratosphere/cfg/cfg_api.hpp

@@ -16,6 +16,7 @@
 #pragma once
 #include "cfg_types.hpp"
 #include "cfg_locale_types.hpp"
+#include "../sm/sm_types.hpp"
 
 namespace ams::cfg {
 
@@ -36,7 +37,7 @@ namespace ams::cfg {
     OverrideLocale GetOverrideLocale(ncm::ProgramId program_id);
 
     /* Flag utilities. */
-    bool HasFlag(ncm::ProgramId program_id, const char *flag);
+    bool HasFlag(const sm::MitmProcessInfo &process_info, const char *flag);
     bool HasContentSpecificFlag(ncm::ProgramId program_id, const char *flag);
     bool HasGlobalFlag(const char *flag);
 

stratosphere/libstratosphere/include/stratosphere/fs/fs_path_tool.hpp

@@ -30,7 +30,7 @@ namespace ams::fs {
 
     class PathTool {
         public:
-            static constexpr fssrv::sf::Path RootPath = fssrv::sf::FspPath::Encode("/");
+            static constexpr const char RootPath[] = "/";
         public:
             static constexpr inline bool IsSeparator(char c) {
                 return c == StringTraits::DirectorySeparator;

stratosphere/libstratosphere/include/stratosphere/fs/fs_remote_filesystem.hpp

@@ -33,7 +33,7 @@ namespace ams::fs {
 
             virtual ~RemoteFile() { fsFileClose(this->base_file.get()); }
         public:
-            virtual Result ReadImpl(size_t *out, s64 offset, void *buffer, size_t size, const ReadOption &option) override final {
+            virtual Result ReadImpl(size_t *out, s64 offset, void *buffer, size_t size, const fs::ReadOption &option) override final {
                 return fsFileRead(this->base_file.get(), offset, buffer, size, option.value, out);
             }
 
@@ -45,7 +45,7 @@ namespace ams::fs {
                 return fsFileFlush(this->base_file.get());
             }
 
-            virtual Result WriteImpl(s64 offset, const void *buffer, size_t size, const WriteOption &option) override final {
+            virtual Result WriteImpl(s64 offset, const void *buffer, size_t size, const fs::WriteOption &option) override final {
                 return fsFileWrite(this->base_file.get(), offset, buffer, size, option.value);
             }
 
@@ -53,7 +53,7 @@ namespace ams::fs {
                 return fsFileSetSize(this->base_file.get(), size);
             }
 
-            virtual Result OperateRangeImpl(void *dst, size_t dst_size, OperationId op_id, s64 offset, s64 size, const void *src, size_t src_size) override final {
+            virtual Result OperateRangeImpl(void *dst, size_t dst_size, fs::OperationId op_id, s64 offset, s64 size, const void *src, size_t src_size) override final {
                 /* TODO: How should this be handled? */
                 return fs::ResultNotImplemented();
             }

stratosphere/libstratosphere/include/stratosphere/fs/fsa/fs_ifile.hpp

@@ -24,7 +24,7 @@ namespace ams::fs::fsa {
         public:
             virtual ~IFile() { /* ... */ }
 
-            Result Read(size_t *out, s64 offset, void *buffer, size_t size, const ReadOption &option) {
+            Result Read(size_t *out, s64 offset, void *buffer, size_t size, const fs::ReadOption &option) {
                 R_UNLESS(out != nullptr, fs::ResultNullptrArgument());
                 if (size == 0) {
                     *out = 0;
@@ -51,7 +51,7 @@ namespace ams::fs::fsa {
                 return this->FlushImpl();
             }
 
-            Result Write(s64 offset, const void *buffer, size_t size, const WriteOption &option) {
+            Result Write(s64 offset, const void *buffer, size_t size, const fs::WriteOption &option) {
                 if (size == 0) {
                     if (option.HasFlushFlag()) {
                         R_TRY(this->Flush());
@@ -71,11 +71,11 @@ namespace ams::fs::fsa {
                 return this->SetSizeImpl(size);
             }
 
-            Result OperateRange(void *dst, size_t dst_size, OperationId op_id, s64 offset, s64 size, const void *src, size_t src_size) {
+            Result OperateRange(void *dst, size_t dst_size, fs::OperationId op_id, s64 offset, s64 size, const void *src, size_t src_size) {
                 return this->OperateRangeImpl(dst, dst_size, op_id, offset, size, src, src_size);
             }
 
-            Result OperateRange(OperationId op_id, s64 offset, s64 size) {
+            Result OperateRange(fs::OperationId op_id, s64 offset, s64 size) {
                 return this->OperateRangeImpl(nullptr, 0, op_id, offset, size, nullptr, 0);
             }
         public:
@@ -84,12 +84,12 @@ namespace ams::fs::fsa {
         protected:
             /* ...? */
         private:
-            virtual Result ReadImpl(size_t *out, s64 offset, void *buffer, size_t size, const ReadOption &option) = 0;
+            virtual Result ReadImpl(size_t *out, s64 offset, void *buffer, size_t size, const fs::ReadOption &option) = 0;
             virtual Result GetSizeImpl(s64 *out) = 0;
             virtual Result FlushImpl() = 0;
-            virtual Result WriteImpl(s64 offset, const void *buffer, size_t size, const WriteOption &option) = 0;
+            virtual Result WriteImpl(s64 offset, const void *buffer, size_t size, const fs::WriteOption &option) = 0;
             virtual Result SetSizeImpl(s64 size) = 0;
-            virtual Result OperateRangeImpl(void *dst, size_t dst_size, OperationId op_id, s64 offset, s64 size, const void *src, size_t src_size) = 0;
+            virtual Result OperateRangeImpl(void *dst, size_t dst_size, fs::OperationId op_id, s64 offset, s64 size, const void *src, size_t src_size) = 0;
     };
 
 }

stratosphere/libstratosphere/include/stratosphere/fssystem.hpp

@@ -19,3 +19,4 @@
 #include "fssystem/fssystem_path_tool.hpp"
 #include "fssystem/fssystem_subdirectory_filesystem.hpp"
 #include "fssystem/fssystem_directory_redirection_filesystem.hpp"
+#include "fssystem/fssystem_directory_savedata_filesystem.hpp"

stratosphere/libstratosphere/include/stratosphere/fssystem/fssystem_directory_redirection_filesystem.hpp

@@ -14,29 +14,33 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #pragma once
-#include "fssystem_path_resolution_filesystem.hpp"
+#include "impl/fssystem_path_resolution_filesystem.hpp"
 
 namespace ams::fssystem {
 
-    class DirectoryRedirectionFileSystem : public IPathResolutionFileSystem<DirectoryRedirectionFileSystem> {
+    class DirectoryRedirectionFileSystem : public impl::IPathResolutionFileSystem<DirectoryRedirectionFileSystem> {
         NON_COPYABLE(DirectoryRedirectionFileSystem);
         private:
-            using PathResolutionFileSystem = IPathResolutionFileSystem<DirectoryRedirectionFileSystem>;
+            using PathResolutionFileSystem = impl::IPathResolutionFileSystem<DirectoryRedirectionFileSystem>;
+            friend class impl::IPathResolutionFileSystem<DirectoryRedirectionFileSystem>;
         private:
             char *before_dir;
             size_t before_dir_len;
             char *after_dir;
             size_t after_dir_len;
-            bool unc_preserved;
         public:
-            DirectoryRedirectionFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *before, const char *after);
-            DirectoryRedirectionFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *before, const char *after, bool unc);
+            DirectoryRedirectionFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *before, const char *after, bool unc = false);
+            DirectoryRedirectionFileSystem(std::unique_ptr<fs::fsa::IFileSystem> &&fs, const char *before, const char *after, bool unc = false);
 
             virtual ~DirectoryRedirectionFileSystem();
+        protected:
+            inline std::optional<std::scoped_lock<os::Mutex>> GetAccessorLock() const {
+                /* No accessor lock is needed. */
+                return std::nullopt;
+            }
         private:
             Result GetNormalizedDirectoryPath(char **out, size_t *out_size, const char *dir);
             Result Initialize(const char *before, const char *after);
-        public:
             Result ResolveFullPath(char *out, size_t out_size, const char *relative_path);
     };
 

stratosphere/libstratosphere/include/stratosphere/fssystem/fssystem_directory_savedata_filesystem.hpp

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2018-2019 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include "impl/fssystem_path_resolution_filesystem.hpp"
+
+namespace ams::fssystem {
+
+    class DirectorySaveDataFileSystem : public impl::IPathResolutionFileSystem<DirectorySaveDataFileSystem> {
+        NON_COPYABLE(DirectorySaveDataFileSystem);
+        private:
+            using PathResolutionFileSystem = impl::IPathResolutionFileSystem<DirectorySaveDataFileSystem>;
+            friend class impl::IPathResolutionFileSystem<DirectorySaveDataFileSystem>;
+        private:
+            os::Mutex accessor_mutex;
+            s32 open_writable_files;
+        public:
+            DirectorySaveDataFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs);
+            DirectorySaveDataFileSystem(std::unique_ptr<fs::fsa::IFileSystem> fs);
+            Result Initialize();
+
+            virtual ~DirectorySaveDataFileSystem();
+        protected:
+            inline std::optional<std::scoped_lock<os::Mutex>> GetAccessorLock() {
+                /* We have a real accessor lock that we want to use. */
+                return std::make_optional<std::scoped_lock<os::Mutex>>(this->accessor_mutex);
+            }
+        private:
+            Result AllocateWorkBuffer(std::unique_ptr<u8[]> *out, size_t *out_size, size_t ideal_size);
+            Result SynchronizeDirectory(const char *dst, const char *src);
+            Result ResolveFullPath(char *out, size_t out_size, const char *relative_path);
+        public:
+            void OnWritableFileClose();
+            Result CopySaveFromFileSystem(fs::fsa::IFileSystem *save_fs);
+        public:
+            /* Overridden from IPathResolutionFileSystem */
+            virtual Result OpenFileImpl(std::unique_ptr<fs::fsa::IFile> *out_file, const char *path, fs::OpenMode mode) override;
+            virtual Result CommitImpl() override;
+
+            /* Overridden from IPathResolutionFileSystem but not commands. */
+            virtual Result CommitProvisionallyImpl(s64 counter) override;
+            virtual Result RollbackImpl() override;
+
+            /* Explicitly overridden to be not implemented. */
+            virtual Result GetFreeSpaceSizeImpl(s64 *out, const char *path) override;
+            virtual Result GetTotalSpaceSizeImpl(s64 *out, const char *path) override;
+            virtual Result GetFileTimeStampRawImpl(fs::FileTimeStampRaw *out, const char *path) override;
+            virtual Result QueryEntryImpl(char *dst, size_t dst_size, const char *src, size_t src_size, fs::fsa::QueryId query, const char *path) override;
+            virtual Result FlushImpl() override;
+    };
+
+}

stratosphere/libstratosphere/include/stratosphere/fssystem/fssystem_subdirectory_filesystem.hpp

@@ -14,26 +14,30 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #pragma once
-#include "fssystem_path_resolution_filesystem.hpp"
+#include "impl/fssystem_path_resolution_filesystem.hpp"
 
 namespace ams::fssystem {
 
-    class SubDirectoryFileSystem : public IPathResolutionFileSystem<SubDirectoryFileSystem> {
+    class SubDirectoryFileSystem : public impl::IPathResolutionFileSystem<SubDirectoryFileSystem> {
         NON_COPYABLE(SubDirectoryFileSystem);
         private:
-            using PathResolutionFileSystem = IPathResolutionFileSystem<SubDirectoryFileSystem>;
+            using PathResolutionFileSystem = impl::IPathResolutionFileSystem<SubDirectoryFileSystem>;
+            friend class impl::IPathResolutionFileSystem<SubDirectoryFileSystem>;
         private:
             char *base_path;
             size_t base_path_len;
-            bool unc_preserved;
         public:
-            SubDirectoryFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *bp);
-            SubDirectoryFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *bp, bool unc);
+            SubDirectoryFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *bp, bool unc = false);
+            SubDirectoryFileSystem(std::unique_ptr<fs::fsa::IFileSystem> &&fs, const char *bp, bool unc = false);
 
             virtual ~SubDirectoryFileSystem();
+        protected:
+            inline std::optional<std::scoped_lock<os::Mutex>> GetAccessorLock() const {
+                /* No accessor lock is needed. */
+                return std::nullopt;
+            }
         private:
             Result Initialize(const char *bp);
-        public:
             Result ResolveFullPath(char *out, size_t out_size, const char *relative_path);
     };
 

stratosphere/libstratosphere/include/stratosphere/fssystem/fssystem_utility.hpp

@@ -15,9 +15,119 @@
  */
 #pragma once
 #include "../fs/fs_common.hpp"
+#include "../fs/fs_file.hpp"
+#include "../fs/fs_directory.hpp"
+#include "../fs/fs_filesystem.hpp"
+#include "fssystem_path_tool.hpp"
 
 namespace ams::fssystem {
 
+    namespace impl {
+
+        /* Iteration. */
+        template<typename OnEnterDir, typename OnExitDir, typename OnFile>
+        Result IterateDirectoryRecursivelyImpl(fs::fsa::IFileSystem *fs, char *work_path, size_t work_path_size, fs::DirectoryEntry *dir_ent, OnEnterDir on_enter_dir, OnExitDir on_exit_dir, OnFile on_file) {
+            /* Open the directory. */
+            std::unique_ptr<fs::fsa::IDirectory> dir;
+            R_TRY(fs->OpenDirectory(&dir, work_path, fs::OpenDirectoryMode_All));
+
+            const size_t parent_len = strnlen(work_path, work_path_size - 1);
+
+            /* Read and handle entries. */
+            while (true) {
+                /* Read a single entry. */
+                s64 read_count = 0;
+                R_TRY(dir->Read(&read_count, dir_ent, 1));
+
+                /* If we're out of entries, we're done. */
+                if (read_count == 0) {
+                    break;
+                }
+
+                /* Validate child path size. */
+                const size_t child_name_len = strnlen(dir_ent->name, sizeof(dir_ent->name) - 1);
+                const bool is_dir = dir_ent->type == fs::DirectoryEntryType_Directory;
+                const size_t separator_size = is_dir ? 1 : 0;
+                R_UNLESS(parent_len + child_name_len + separator_size < work_path_size, fs::ResultTooLongPath());
+
+                /* Set child path. */
+                std::strncat(work_path, dir_ent->name, work_path_size - parent_len - 1);
+                {
+                    if (is_dir) {
+                        /* Enter directory. */
+                        R_TRY(on_enter_dir(work_path, *dir_ent));
+
+                        /* Append separator, recurse. */
+                        std::strncat(work_path, "/", work_path_size - (parent_len + child_name_len) - 1);
+                        R_TRY(IterateDirectoryRecursivelyImpl(fs, work_path, work_path_size, dir_ent, on_enter_dir, on_exit_dir, on_file));
+
+                        /* Exit directory. */
+                        R_TRY(on_exit_dir(work_path, *dir_ent));
+                    } else {
+                        /* Call file handler. */
+                        R_TRY(on_file(work_path, *dir_ent));
+                    }
+                }
+
+                /* Restore parent path. */
+                work_path[parent_len] = StringTraits::NullTerminator;
+            }
+
+            return ResultSuccess();
+        }
+
+        /* TODO: Cleanup. */
+
+    }
+
+    /* Iteration API */
+    template<typename OnEnterDir, typename OnExitDir, typename OnFile>
+    Result IterateDirectoryRecursively(fs::fsa::IFileSystem *fs, const char *root_path, char *work_path, size_t work_path_size, fs::DirectoryEntry *dir_ent_buf, OnEnterDir on_enter_dir, OnExitDir on_exit_dir, OnFile on_file) {
+        AMS_ASSERT(work_path_size >= fs::EntryNameLengthMax + 1);
+
+        /* Get size of the root path. */
+        size_t root_path_len = strnlen(root_path, fs::EntryNameLengthMax + 1);
+        R_UNLESS(root_path_len <= fs::EntryNameLengthMax, fs::ResultTooLongPath());
+
+        /* Copy root path in, add a / if necessary. */
+        std::memcpy(work_path, root_path, root_path_len);
+        if (!PathTool::IsSeparator(work_path[root_path_len - 1])) {
+            work_path[root_path_len++] = StringTraits::DirectorySeparator;
+        }
+
+        /* Make sure the result path is still valid. */
+        R_UNLESS(root_path_len <= fs::EntryNameLengthMax, fs::ResultTooLongPath());
+        work_path[root_path_len] = StringTraits::NullTerminator;
+
+        return impl::IterateDirectoryRecursivelyImpl(fs, work_path, work_path_size, dir_ent_buf, on_enter_dir, on_exit_dir, on_file);
+    }
+
+    template<typename OnEnterDir, typename OnExitDir, typename OnFile>
+    Result IterateDirectoryRecursively(fs::fsa::IFileSystem *fs, const char *root_path, OnEnterDir on_enter_dir, OnExitDir on_exit_dir, OnFile on_file) {
+        fs::DirectoryEntry dir_entry = {};
+        char work_path[fs::EntryNameLengthMax + 1] = {};
+        return IterateDirectoryRecursively(fs, root_path, work_path, sizeof(work_path), &dir_entry, on_enter_dir, on_exit_dir, on_file);
+    }
+
+    template<typename OnEnterDir, typename OnExitDir, typename OnFile>
+    Result IterateDirectoryRecursively(fs::fsa::IFileSystem *fs, OnEnterDir on_enter_dir, OnExitDir on_exit_dir, OnFile on_file) {
+        return IterateDirectoryRecursively(fs, PathTool::RootPath, on_enter_dir, on_exit_dir, on_file);
+    }
+
+    /* TODO: Cleanup API */
+
+    /* Copy API. */
+    Result CopyFile(fs::fsa::IFileSystem *dst_fs, fs::fsa::IFileSystem *src_fs, const char *dst_parent_path, const char *src_path, const fs::DirectoryEntry *dir_ent, void *work_buf, size_t work_buf_size);
+    NX_INLINE Result CopyFile(fs::fsa::IFileSystem *fs, const char *dst_parent_path, const char *src_path, const fs::DirectoryEntry *dir_ent, void *work_buf, size_t work_buf_size) {
+        return CopyFile(fs, fs, dst_parent_path, src_path, dir_ent, work_buf, work_buf_size);
+    }
+
+    Result CopyDirectoryRecursively(fs::fsa::IFileSystem *dst_fs, fs::fsa::IFileSystem *src_fs, const char *dst_path, const char *src_path, void *work_buf, size_t work_buf_size);
+    NX_INLINE Result CopyDirectoryRecursively(fs::fsa::IFileSystem *fs, const char *dst_path, const char *src_path, void *work_buf, size_t work_buf_size) {
+        return CopyDirectoryRecursively(fs, fs, dst_path, src_path, work_buf, work_buf_size);
+    }
+
+    /* Semaphore adapter class. */
     class SemaphoreAdapter : public os::Semaphore {
         public:
             SemaphoreAdapter(int c, int mc) : os::Semaphore(c, mc) { /* ... */ }
@@ -31,4 +141,29 @@ namespace ams::fssystem {
             }
     };
 
+    /* Other utility. */
+    Result EnsureDirectoryExistsRecursively(fs::fsa::IFileSystem *fs, const char *path);
+
+    template<typename F>
+    NX_INLINE Result RetryFinitelyForTargetLocked(F f) {
+        /* Retry up to 10 times, 100ms between retries. */
+        constexpr s32 MaxRetryCount = 10;
+        constexpr u64 RetryWaitTime = 100'000'000ul;
+
+        s32 remaining_retries = MaxRetryCount;
+        while (true) {
+            R_TRY_CATCH(f()) {
+                R_CATCH(fs::ResultTargetLocked) {
+                    R_UNLESS(remaining_retries > 0, fs::ResultTargetLocked());
+
+                    remaining_retries--;
+                    svcSleepThread(RetryWaitTime);
+                    continue;
+                }
+            } R_END_TRY_CATCH;
+
+            return ResultSuccess();
+        }
+    }
+
 }

stratosphere/libstratosphere/include/stratosphere/fssystem/impl/fssystem_path_resolution_filesystem.hpp

@@ -14,27 +14,29 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #pragma once
-#include "../fs/fs_common.hpp"
-#include "../fs/fsa/fs_ifile.hpp"
-#include "../fs/fsa/fs_idirectory.hpp"
-#include "../fs/fsa/fs_ifilesystem.hpp"
+#include "../../fs/fs_common.hpp"
+#include "../../fs/fsa/fs_ifile.hpp"
+#include "../../fs/fsa/fs_idirectory.hpp"
+#include "../../fs/fsa/fs_ifilesystem.hpp"
 
-namespace ams::fssystem {
+namespace ams::fssystem::impl {
 
     template<typename Impl>
     class IPathResolutionFileSystem : public fs::fsa::IFileSystem {
         NON_COPYABLE(IPathResolutionFileSystem);
         private:
             std::shared_ptr<fs::fsa::IFileSystem> shared_fs;
-            fs::fsa::IFileSystem *base_fs;
+            std::unique_ptr<fs::fsa::IFileSystem> unique_fs;
             bool unc_preserved;
+        protected:
+            fs::fsa::IFileSystem * const base_fs;
         public:
-            IPathResolutionFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs) : shared_fs(std::move(fs)), unc_preserved(false) {
-                this->base_fs = this->shared_fs.get();
+            IPathResolutionFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, bool unc = false) : shared_fs(std::move(fs)), unc_preserved(unc), base_fs(shared_fs.get())  {
+                /* ... */
             }
 
-            IPathResolutionFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, bool unc) : shared_fs(std::move(fs)), unc_preserved(unc) {
-                this->base_fs = this->shared_fs.get();
+            IPathResolutionFileSystem(std::unique_ptr<fs::fsa::IFileSystem> &&fs, bool unc = false) : unique_fs(std::move(fs)), unc_preserved(unc), base_fs(unique_fs.get())  {
+                /* ... */
             }
 
             virtual ~IPathResolutionFileSystem() { /* ... */ }
@@ -47,6 +49,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->CreateFile(full_path, size, option);
             }
 
@@ -54,6 +57,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->DeleteFile(full_path);
             }
 
@@ -61,6 +65,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->CreateDirectory(full_path);
             }
 
@@ -68,6 +73,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->DeleteDirectory(full_path);
             }
 
@@ -75,6 +81,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->DeleteDirectoryRecursively(full_path);
             }
 
@@ -84,6 +91,7 @@ namespace ams::fssystem {
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(old_full_path, sizeof(old_full_path), old_path));
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(new_full_path, sizeof(new_full_path), new_path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->RenameFile(old_path, new_path);
             }
 
@@ -93,6 +101,7 @@ namespace ams::fssystem {
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(old_full_path, sizeof(old_full_path), old_path));
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(new_full_path, sizeof(new_full_path), new_path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->RenameDirectory(old_path, new_path);
             }
 
@@ -100,6 +109,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->GetEntryType(out, full_path);
             }
 
@@ -107,6 +117,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->OpenFile(out_file, full_path, mode);
             }
 
@@ -114,17 +125,20 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->OpenDirectory(out_dir, full_path, mode);
             }
 
             virtual Result CommitImpl() override {
-                return this->base_fs->Rollback();
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
+                return this->base_fs->Commit();
             }
 
             virtual Result GetFreeSpaceSizeImpl(s64 *out, const char *path) override {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->GetFreeSpaceSize(out, full_path);
             }
 
@@ -132,6 +146,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->GetTotalSpaceSize(out, full_path);
             }
 
@@ -139,6 +154,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->CleanDirectoryRecursively(full_path);
             }
 
@@ -146,6 +162,7 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->GetFileTimeStampRaw(out, full_path);
             }
 
@@ -153,19 +170,23 @@ namespace ams::fssystem {
                 char full_path[fs::EntryNameLengthMax + 1];
                 R_TRY(static_cast<Impl*>(this)->ResolveFullPath(full_path, sizeof(full_path), path));
 
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->QueryEntry(dst, dst_size, src, src_size, query, full_path);
             }
 
             /* These aren't accessible as commands. */
             virtual Result CommitProvisionallyImpl(s64 counter) override {
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->CommitProvisionally(counter);
             }
 
             virtual Result RollbackImpl() override {
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->Rollback();
             }
 
             virtual Result FlushImpl() override {
+                std::optional optional_lock = static_cast<Impl*>(this)->GetAccessorLock();
                 return this->base_fs->Flush();
             }
     };

stratosphere/libstratosphere/include/stratosphere/sf/cmif/sf_cmif_domain_service_object.hpp

@@ -56,6 +56,10 @@ namespace ams::sf::cmif {
                 return this->impl_metadata.GetOutObjectCount();
             }
 
+            constexpr size_t GetImplOutHeadersSize() const {
+                return this->impl_metadata.GetOutHeadersSize();
+            }
+
             constexpr size_t GetImplOutDataTotalSize() const {
                 return this->impl_metadata.GetOutDataSize() + this->impl_metadata.GetOutHeadersSize();
             }

stratosphere/libstratosphere/source/cfg/cfg_flags.cpp

@@ -47,8 +47,8 @@ namespace ams::cfg {
     }
 
     /* Flag utilities. */
-    bool HasFlag(ncm::ProgramId program_id, const char *flag) {
-        return HasContentSpecificFlag(program_id, flag) || (IsHblProgramId(program_id) && HasHblFlag(flag));
+    bool HasFlag(const sm::MitmProcessInfo &process_info, const char *flag) {
+        return HasContentSpecificFlag(process_info.program_id, flag) || (process_info.override_status.IsHbl() && HasHblFlag(flag));
     }
 
     bool HasContentSpecificFlag(ncm::ProgramId program_id, const char *flag) {

stratosphere/libstratosphere/source/fssystem/fssystem_directory_redirection_filesystem.cpp

@@ -17,13 +17,17 @@
 
 namespace ams::fssystem {
 
-    DirectoryRedirectionFileSystem::DirectoryRedirectionFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *before, const char *after) : PathResolutionFileSystem(fs) {
+    DirectoryRedirectionFileSystem::DirectoryRedirectionFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *before, const char *after, bool unc)
+        : PathResolutionFileSystem(fs, unc)
+    {
         this->before_dir = nullptr;
         this->after_dir = nullptr;
         R_ASSERT(this->Initialize(before, after));
     }
 
-    DirectoryRedirectionFileSystem::DirectoryRedirectionFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *before, const char *after, bool unc) : PathResolutionFileSystem(fs, unc) {
+    DirectoryRedirectionFileSystem::DirectoryRedirectionFileSystem(std::unique_ptr<fs::fsa::IFileSystem> &&fs, const char *before, const char *after, bool unc)
+        : PathResolutionFileSystem(std::forward<std::unique_ptr<fs::fsa::IFileSystem>>(fs), unc)
+    {
         this->before_dir = nullptr;
         this->after_dir = nullptr;
         R_ASSERT(this->Initialize(before, after));

stratosphere/libstratosphere/source/fssystem/fssystem_directory_savedata_filesystem.cpp

@@ -0,0 +1,272 @@
+/*
+ * Copyright (c) 2018-2019 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+
+namespace ams::fssystem {
+
+    namespace {
+
+        constexpr size_t IdealWorkBufferSize = 0x100000; /* 1 MiB */
+
+        constexpr const char CommittedDirectoryPath[]     = "/0/";
+        constexpr const char WorkingDirectoryPath[]       = "/1/";
+        constexpr const char SynchronizingDirectoryPath[] = "/_/";
+
+        class DirectorySaveDataFile : public fs::fsa::IFile {
+            private:
+                std::unique_ptr<fs::fsa::IFile> base_file;
+                DirectorySaveDataFileSystem *parent_fs;
+                fs::OpenMode open_mode;
+            public:
+                DirectorySaveDataFile(std::unique_ptr<fs::fsa::IFile> f, DirectorySaveDataFileSystem *p, fs::OpenMode m) : base_file(std::move(f)), parent_fs(p), open_mode(m) {
+                    /* ... */
+                }
+
+                virtual ~DirectorySaveDataFile() {
+                    /* Observe closing of writable file. */
+                    if (this->open_mode & fs::OpenMode_Write) {
+                        this->parent_fs->OnWritableFileClose();
+                    }
+                }
+            public:
+                virtual Result ReadImpl(size_t *out, s64 offset, void *buffer, size_t size, const fs::ReadOption &option) override {
+                    return this->base_file->Read(out, offset, buffer, size, option);
+                }
+
+                virtual Result GetSizeImpl(s64 *out) override {
+                    return this->base_file->GetSize(out);
+                }
+
+                virtual Result FlushImpl() override {
+                    return this->base_file->Flush();
+                }
+
+                virtual Result WriteImpl(s64 offset, const void *buffer, size_t size, const fs::WriteOption &option) override {
+                    return this->base_file->Write(offset, buffer, size, option);
+                }
+
+                virtual Result SetSizeImpl(s64 size) override {
+                    return this->base_file->SetSize(size);
+                }
+
+                virtual Result OperateRangeImpl(void *dst, size_t dst_size, fs::OperationId op_id, s64 offset, s64 size, const void *src, size_t src_size) override {
+                    return this->base_file->OperateRange(dst, dst_size, op_id, offset, size, src, src_size);
+                }
+            public:
+                virtual sf::cmif::DomainObjectId GetDomainObjectId() const override {
+                    return this->base_file->GetDomainObjectId();
+                }
+        };
+
+    }
+
+    DirectorySaveDataFileSystem::DirectorySaveDataFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs)
+        : PathResolutionFileSystem(fs)
+    {
+        /* ... */
+    }
+
+    DirectorySaveDataFileSystem::DirectorySaveDataFileSystem(std::unique_ptr<fs::fsa::IFileSystem> fs)
+        : PathResolutionFileSystem(std::forward<std::unique_ptr<fs::fsa::IFileSystem>>(fs))
+    {
+        /* ... */
+    }
+
+    DirectorySaveDataFileSystem::~DirectorySaveDataFileSystem() {
+        /* ... */
+    }
+
+    Result DirectorySaveDataFileSystem::Initialize() {
+        /* Nintendo does not acquire the lock here, but I think we probably should. */
+        std::scoped_lock lk(this->accessor_mutex);
+
+        fs::DirectoryEntryType type;
+
+        /* Check that the working directory exists. */
+        R_TRY_CATCH(this->base_fs->GetEntryType(&type, WorkingDirectoryPath)) {
+            /* If path isn't found, create working directory and committed directory. */
+            R_CATCH(fs::ResultPathNotFound) {
+                R_TRY(this->base_fs->CreateDirectory(WorkingDirectoryPath));
+                R_TRY(this->base_fs->CreateDirectory(CommittedDirectoryPath));
+            }
+        } R_END_TRY_CATCH;
+
+        /* Now check for the committed directory. */
+        R_TRY_CATCH(this->base_fs->GetEntryType(&type, CommittedDirectoryPath)) {
+            /* Committed doesn't exist, so synchronize and rename. */
+            R_CATCH(fs::ResultPathNotFound) {
+                R_TRY(this->SynchronizeDirectory(SynchronizingDirectoryPath, WorkingDirectoryPath));
+                R_TRY(this->base_fs->RenameDirectory(SynchronizingDirectoryPath, CommittedDirectoryPath));
+                return ResultSuccess();
+            }
+        } R_END_TRY_CATCH;
+
+        /* The committed directory exists, so synchronize it to the working directory. */
+        return this->SynchronizeDirectory(WorkingDirectoryPath, CommittedDirectoryPath);
+    }
+
+    Result DirectorySaveDataFileSystem::AllocateWorkBuffer(std::unique_ptr<u8[]> *out, size_t *out_size, size_t size) {
+        /* Repeatedly try to allocate until success. */
+        while (size > 0x200) {
+            /* Allocate the buffer. */
+            if (auto mem = new (std::nothrow) u8[size]; mem != nullptr) {
+                out->reset(mem);
+                *out_size = size;
+                return ResultSuccess();
+            } else {
+                /* Divide size by two. */
+                size >>= 1;
+            }
+        }
+
+        /* TODO: Return a result here? Nintendo does not, but they have other allocation failed results. */
+        /* Consider returning ResultFsAllocationFailureInDirectorySaveDataFileSystem? */
+        AMS_ASSERT(false);
+    }
+
+    Result DirectorySaveDataFileSystem::SynchronizeDirectory(const char *dst, const char *src) {
+        /* Delete destination dir and recreate it. */
+        R_TRY_CATCH(this->base_fs->DeleteDirectoryRecursively(dst)) {
+            R_CATCH(fs::ResultPathNotFound) { /* Nintendo returns error unconditionally, but I think that's a bug in their code. */}
+        } R_END_TRY_CATCH;
+
+        R_TRY(this->base_fs->CreateDirectory(dst));
+
+        /* Get a work buffer to work with. */
+        std::unique_ptr<u8[]> work_buf;
+        size_t work_buf_size;
+        R_TRY(this->AllocateWorkBuffer(&work_buf, &work_buf_size, IdealWorkBufferSize));
+
+        /* Copy the directory recursively. */
+        return fssystem::CopyDirectoryRecursively(this->base_fs, dst, src, work_buf.get(), work_buf_size);
+    }
+
+    Result DirectorySaveDataFileSystem::ResolveFullPath(char *out, size_t out_size, const char *relative_path) {
+        R_UNLESS(strnlen(relative_path, fs::EntryNameLengthMax + 1) < fs::EntryNameLengthMax + 1, fs::ResultTooLongPath());
+        R_UNLESS(PathTool::IsSeparator(relative_path[0]), fs::ResultInvalidPath());
+
+        /* Copy working directory path. */
+        std::strncpy(out, WorkingDirectoryPath, out_size);
+        out[out_size - 1] = StringTraits::NullTerminator;
+
+        /* Normalize it. */
+        constexpr size_t WorkingDirectoryPathLength = sizeof(WorkingDirectoryPath) - 1;
+        size_t normalized_length;
+        return PathTool::Normalize(out + WorkingDirectoryPathLength - 1, &normalized_length, relative_path, out_size - (WorkingDirectoryPathLength - 1));
+    }
+
+    void DirectorySaveDataFileSystem::OnWritableFileClose() {
+        std::scoped_lock lk(this->accessor_mutex);
+        this->open_writable_files--;
+
+        /* Nintendo does not check this, but I think it's sensible to do so. */
+        AMS_ASSERT(this->open_writable_files >= 0);
+    }
+
+    Result DirectorySaveDataFileSystem::CopySaveFromFileSystem(fs::fsa::IFileSystem *save_fs) {
+        /* If the input save is null, there's nothing to copy. */
+        R_UNLESS(save_fs != nullptr, ResultSuccess());
+
+        /* Get a work buffer to work with. */
+        std::unique_ptr<u8[]> work_buf;
+        size_t work_buf_size;
+        R_TRY(this->AllocateWorkBuffer(&work_buf, &work_buf_size, IdealWorkBufferSize));
+
+        /* Copy the directory recursively. */
+        R_TRY(fssystem::CopyDirectoryRecursively(this->base_fs, save_fs, PathTool::RootPath, PathTool::RootPath, work_buf.get(), work_buf_size));
+
+        return this->Commit();
+    }
+
+    /* Overridden from IPathResolutionFileSystem */
+    Result DirectorySaveDataFileSystem::OpenFileImpl(std::unique_ptr<fs::fsa::IFile> *out_file, const char *path, fs::OpenMode mode) {
+        char full_path[fs::EntryNameLengthMax + 1];
+        R_TRY(this->ResolveFullPath(full_path, sizeof(full_path), path));
+
+        std::scoped_lock lk(this->accessor_mutex);
+        std::unique_ptr<fs::fsa::IFile> base_file;
+        R_TRY(this->base_fs->OpenFile(&base_file, full_path, mode));
+
+        std::unique_ptr<DirectorySaveDataFile> file(new (std::nothrow) DirectorySaveDataFile(std::move(base_file), this, mode));
+        R_UNLESS(file != nullptr, fs::ResultAllocationFailureInDirectorySaveDataFileSystem());
+
+        if (mode & fs::OpenMode_Write) {
+            this->open_writable_files++;
+        }
+
+        *out_file = std::move(file);
+        return ResultSuccess();
+    }
+
+    Result DirectorySaveDataFileSystem::CommitImpl() {
+        /* Here, Nintendo does the following (with retries): */
+        /* - Rename Committed -> Synchronizing. */
+        /* - Synchronize Working -> Synchronizing (deleting Synchronizing). */
+        /* - Rename Synchronizing -> Committed. */
+        std::scoped_lock lk(this->accessor_mutex);
+
+        R_UNLESS(this->open_writable_files == 0, fs::ResultPreconditionViolation());
+
+        const auto RenameCommitedDir      = [&]() { return this->base_fs->RenameDirectory(CommittedDirectoryPath, SynchronizingDirectoryPath); };
+        const auto SynchronizeWorkingDir  = [&]() { return this->SynchronizeDirectory(SynchronizingDirectoryPath, WorkingDirectoryPath); };
+        const auto RenameSynchronizingDir = [&]() { return this->base_fs->RenameDirectory(SynchronizingDirectoryPath, CommittedDirectoryPath); };
+
+        /* Rename Committed -> Synchronizing. */
+        R_TRY(fssystem::RetryFinitelyForTargetLocked(std::move(RenameCommitedDir)));
+
+        /* - Synchronize Working -> Synchronizing (deleting Synchronizing). */
+        R_TRY(fssystem::RetryFinitelyForTargetLocked(std::move(SynchronizeWorkingDir)));
+
+        /* - Rename Synchronizing -> Committed. */
+        R_TRY(fssystem::RetryFinitelyForTargetLocked(std::move(RenameSynchronizingDir)));
+
+        /* TODO: Should I call this->base_fs->Commit()? Nintendo does not. */
+        return ResultSuccess();
+    }
+
+    /* Overridden from IPathResolutionFileSystem but not commands. */
+    Result DirectorySaveDataFileSystem::CommitProvisionallyImpl(s64 counter) {
+        /* Nintendo does nothing here. */
+        return ResultSuccess();
+    }
+
+    Result DirectorySaveDataFileSystem::RollbackImpl() {
+        /* Initialize overwrites the working directory with the committed directory. */
+        return this->Initialize();
+    }
+
+    /* Explicitly overridden to be not implemented. */
+    Result DirectorySaveDataFileSystem::GetFreeSpaceSizeImpl(s64 *out, const char *path) {
+        return fs::ResultNotImplemented();
+    }
+
+    Result DirectorySaveDataFileSystem::GetTotalSpaceSizeImpl(s64 *out, const char *path) {
+        return fs::ResultNotImplemented();
+    }
+
+    Result DirectorySaveDataFileSystem::GetFileTimeStampRawImpl(fs::FileTimeStampRaw *out, const char *path) {
+        return fs::ResultNotImplemented();
+    }
+
+    Result DirectorySaveDataFileSystem::QueryEntryImpl(char *dst, size_t dst_size, const char *src, size_t src_size, fs::fsa::QueryId query, const char *path) {
+        return fs::ResultNotImplemented();
+    }
+
+    Result DirectorySaveDataFileSystem::FlushImpl() {
+        return fs::ResultNotImplemented();
+    }
+
+}

stratosphere/libstratosphere/source/fssystem/fssystem_subdirectory_filesystem.cpp

@@ -17,12 +17,16 @@
 
 namespace ams::fssystem {
 
-    SubDirectoryFileSystem::SubDirectoryFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *bp) : PathResolutionFileSystem(fs) {
+    SubDirectoryFileSystem::SubDirectoryFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *bp, bool unc)
+        : PathResolutionFileSystem(fs, unc)
+    {
         this->base_path = nullptr;
         R_ASSERT(this->Initialize(bp));
     }
 
-    SubDirectoryFileSystem::SubDirectoryFileSystem(std::shared_ptr<fs::fsa::IFileSystem> fs, const char *bp, bool unc) : PathResolutionFileSystem(fs, unc) {
+    SubDirectoryFileSystem::SubDirectoryFileSystem(std::unique_ptr<fs::fsa::IFileSystem> &&fs, const char *bp, bool unc)
+        : PathResolutionFileSystem(std::forward<std::unique_ptr<fs::fsa::IFileSystem>>(fs), unc)
+    {
         this->base_path = nullptr;
         R_ASSERT(this->Initialize(bp));
     }

stratosphere/libstratosphere/source/fssystem/fssystem_utility.cpp

@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2018-2019 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+
+namespace ams::fssystem {
+
+    namespace {
+
+        inline Result EnsureDirectoryExists(fs::fsa::IFileSystem *fs, const char *path) {
+            R_TRY_CATCH(fs->CreateDirectory(path)) {
+                R_CATCH(fs::ResultPathAlreadyExists) { /* If path already exists, there's no problem. */ }
+            } R_END_TRY_CATCH;
+
+            return ResultSuccess();
+        }
+
+    }
+
+    Result CopyFile(fs::fsa::IFileSystem *dst_fs, fs::fsa::IFileSystem *src_fs, const char *dst_parent_path, const char *src_path, const fs::DirectoryEntry *entry, void *work_buf, size_t work_buf_size) {
+        /* Open source file. */
+        std::unique_ptr<fs::fsa::IFile> src_file;
+        R_TRY(src_fs->OpenFile(&src_file, src_path, fs::OpenMode_Read));
+
+        /* Open dst file. */
+        std::unique_ptr<fs::fsa::IFile> dst_file;
+        {
+            char dst_path[fs::EntryNameLengthMax + 1];
+            const size_t original_size = static_cast<size_t>(std::snprintf(dst_path, sizeof(dst_path), "%s%s", dst_parent_path, entry->name));
+            /* TODO: Error code? N aborts here. */
+            AMS_ASSERT(original_size < sizeof(dst_path));
+
+            R_TRY(dst_fs->CreateFile(dst_path, entry->file_size));
+            R_TRY(dst_fs->OpenFile(&dst_file, dst_path, fs::OpenMode_Write));
+        }
+
+        /* Read/Write file in work buffer sized chunks. */
+        s64 remaining = entry->file_size;
+        s64 offset = 0;
+        while (remaining > 0) {
+            size_t read_size;
+            R_TRY(src_file->Read(&read_size, offset, work_buf, work_buf_size, fs::ReadOption()));
+            R_TRY(dst_file->Write(offset, work_buf, read_size, fs::WriteOption()));
+
+            remaining -= read_size;
+            offset    += read_size;
+        }
+
+        return ResultSuccess();
+    }
+
+    Result CopyDirectoryRecursively(fs::fsa::IFileSystem *dst_fs, fs::fsa::IFileSystem *src_fs, const char *dst_path, const char *src_path, void *work_buf, size_t work_buf_size) {
+        char dst_path_buf[fs::EntryNameLengthMax + 1];
+        const size_t original_size = static_cast<size_t>(std::snprintf(dst_path_buf, sizeof(dst_path_buf), "%s", dst_path));
+        AMS_ASSERT(original_size < sizeof(dst_path_buf));
+
+        return IterateDirectoryRecursively(src_fs, src_path,
+            [&](const char *path, const fs::DirectoryEntry &entry) -> Result { /* On Enter Directory */
+                /* Update path, create new dir. */
+                std::strncat(dst_path_buf, entry.name, sizeof(dst_path_buf) - strnlen(dst_path_buf, sizeof(dst_path_buf) - 1) - 1);
+                std::strncat(dst_path_buf, "/",        sizeof(dst_path_buf) - strnlen(dst_path_buf, sizeof(dst_path_buf) - 1) - 1);
+                return dst_fs->CreateDirectory(dst_path_buf);
+            },
+            [&](const char *path, const fs::DirectoryEntry &entry) -> Result { /* On Exit Directory */
+                /* Check we have a parent directory. */
+                const size_t len = strnlen(dst_path_buf, sizeof(dst_path_buf));
+                R_UNLESS(len >= 2, fs::ResultInvalidPathFormat());
+
+                /* Find previous separator, add null terminator */
+                char *cur = &dst_path_buf[len - 2];
+                while (!PathTool::IsSeparator(*cur) && cur > dst_path_buf) {
+                    cur--;
+                }
+                cur[1] = StringTraits::NullTerminator;
+
+                return ResultSuccess();
+            },
+            [&](const char *path, const fs::DirectoryEntry &entry) -> Result { /* On File */
+                return CopyFile(dst_fs, src_fs, dst_path_buf, path, &entry, work_buf, work_buf_size);
+            }
+        );
+    }
+
+    Result EnsureDirectoryExistsRecursively(fs::fsa::IFileSystem *fs, const char *path) {
+        /* Normalize the path. */
+        char normalized_path[fs::EntryNameLengthMax + 1];
+        size_t normalized_path_len;
+        R_TRY(PathTool::Normalize(normalized_path, &normalized_path_len, path, sizeof(normalized_path)));
+
+        /* Repeatedly call CreateDirectory on each directory leading to the target. */
+        for (size_t i = 1; i < normalized_path_len; i++) {
+            /* If we detect a separator, create the directory. */
+            if (PathTool::IsSeparator(normalized_path[i])) {
+                normalized_path[i] = StringTraits::NullTerminator;
+                R_TRY(EnsureDirectoryExists(fs, normalized_path));
+                normalized_path[i] = StringTraits::DirectorySeparator;
+            }
+        }
+
+        /* Call CreateDirectory on the final path. */
+        R_TRY(EnsureDirectoryExists(fs, normalized_path));
+
+        return ResultSuccess();
+    }
+
+}

stratosphere/libstratosphere/source/sf/cmif/sf_cmif_domain_service_object.cpp

@@ -149,8 +149,8 @@ namespace ams::sf::cmif {
 
         /* Write out header. */
         constexpr size_t out_header_size = sizeof(CmifDomainOutHeader);
-        const size_t impl_out_data_total_size = this->GetImplOutDataTotalSize();
-        AMS_ASSERT(out_header_size + impl_out_data_total_size <= raw_data.GetSize());
+        const size_t impl_out_headers_size = this->GetImplOutHeadersSize();
+        AMS_ASSERT(out_header_size + impl_out_headers_size <= raw_data.GetSize());
         *reinterpret_cast<CmifDomainOutHeader *>(raw_data.GetPointer()) = CmifDomainOutHeader{ .num_out_objects = 0, };
 
         /* Set output raw data. */