Filesystem/Archives: Implemented the SaveData archive

The savedata for each game is stored in /savedata/<ProgramID> for NCCH files. ELF files and 3DSX files use the folder 0 because they have no ID information

Got rid of the code duplication in File and Directory

Files that deal with the host machine's file system now live in DiskFile, similarly for directories and DiskDirectory and archives with DiskArchive.

FS_U: Use the correct error code when a file wasn't found

25 files changed, 458 insertions, 490 deletions

diff --git a/src/common/common_paths.h b/src/common/common_paths.h
index 42e1a29c..a8688975 100644
--- a/src/common/common_paths.h
+++ b/src/common/common_paths.h
@@ -40,6 +40,7 @@
 #define MAPS_DIR          "maps"
 #define CACHE_DIR         "cache"
 #define SDMC_DIR          "sdmc"
+#define SAVEDATA_DIR      "savedata"
 #define SYSDATA_DIR       "sysdata"
 #define SHADERCACHE_DIR   "shader_cache"
 #define STATESAVES_DIR    "state_saves"
diff --git a/src/common/file_util.cpp b/src/common/file_util.cpp
index 88c46c11..42cdf326 100644
--- a/src/common/file_util.cpp
+++ b/src/common/file_util.cpp
@@ -676,6 +676,7 @@ const std::string& GetUserPath(const unsigned int DirIDX, const std::string &new
         paths[D_MAPS_IDX]           = paths[D_USER_IDX] + MAPS_DIR DIR_SEP;
         paths[D_CACHE_IDX]          = paths[D_USER_IDX] + CACHE_DIR DIR_SEP;
         paths[D_SDMC_IDX]           = paths[D_USER_IDX] + SDMC_DIR DIR_SEP;
+        paths[D_SAVEDATA_IDX]       = paths[D_USER_IDX] + SAVEDATA_DIR DIR_SEP;
         paths[D_SYSDATA_IDX]        = paths[D_USER_IDX] + SYSDATA_DIR DIR_SEP;
         paths[D_SHADERCACHE_IDX]    = paths[D_USER_IDX] + SHADERCACHE_DIR DIR_SEP;
         paths[D_SHADERS_IDX]        = paths[D_USER_IDX] + SHADERS_DIR DIR_SEP;
@@ -718,6 +719,7 @@ const std::string& GetUserPath(const unsigned int DirIDX, const std::string &new
             paths[D_MAPS_IDX]           = paths[D_USER_IDX] + MAPS_DIR DIR_SEP;
             paths[D_CACHE_IDX]          = paths[D_USER_IDX] + CACHE_DIR DIR_SEP;
             paths[D_SDMC_IDX]           = paths[D_USER_IDX] + SDMC_DIR DIR_SEP;
+            paths[D_SAVEDATA_IDX]       = paths[D_USER_IDX] + SAVEDATA_DIR DIR_SEP;
             paths[D_SHADERCACHE_IDX]    = paths[D_USER_IDX] + SHADERCACHE_DIR DIR_SEP;
             paths[D_SHADERS_IDX]        = paths[D_USER_IDX] + SHADERS_DIR DIR_SEP;
             paths[D_STATESAVES_IDX]     = paths[D_USER_IDX] + STATESAVES_DIR DIR_SEP;
diff --git a/src/common/file_util.h b/src/common/file_util.h
index a9d48cfe..e691b613 100644
--- a/src/common/file_util.h
+++ b/src/common/file_util.h
@@ -27,6 +27,7 @@ enum {
     D_STATESAVES_IDX,
     D_SCREENSHOTS_IDX,
     D_SDMC_IDX,
+    D_SAVEDATA_IDX,
     D_SYSDATA_IDX,
     D_HIRESTEXTURES_IDX,
     D_DUMP_IDX,
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 198e4afd..f71232c1 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -18,11 +18,11 @@ set(SRCS
             arm/skyeye_common/vfp/vfpinstr.cpp
             arm/skyeye_common/vfp/vfpsingle.cpp
             file_sys/archive_romfs.cpp
+            file_sys/archive_savedata.cpp
             file_sys/archive_sdmc.cpp
+            file_sys/disk_archive.cpp
             file_sys/file_romfs.cpp
-            file_sys/file_sdmc.cpp
             file_sys/directory_romfs.cpp
-            file_sys/directory_sdmc.cpp
             hle/kernel/address_arbiter.cpp
             hle/kernel/event.cpp
             hle/kernel/kernel.cpp
@@ -99,13 +99,13 @@ set(HEADERS
             arm/arm_interface.h
             file_sys/archive_backend.h
             file_sys/archive_romfs.h
+            file_sys/archive_savedata.h
             file_sys/archive_sdmc.h
+            file_sys/disk_archive.h
             file_sys/file_backend.h
             file_sys/file_romfs.h
-            file_sys/file_sdmc.h
             file_sys/directory_backend.h
             file_sys/directory_romfs.h
-            file_sys/directory_sdmc.h
             hle/kernel/address_arbiter.h
             hle/kernel/event.h
             hle/kernel/kernel.h
diff --git a/src/core/file_sys/archive_savedata.cpp b/src/core/file_sys/archive_savedata.cpp
new file mode 100644
index 00000000..2414564e
--- /dev/null
+++ b/src/core/file_sys/archive_savedata.cpp
@@ -0,0 +1,33 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include <sys/stat.h>
+
+#include "common/common_types.h"
+#include "common/file_util.h"
+
+#include "core/file_sys/archive_savedata.h"
+#include "core/file_sys/disk_archive.h"
+#include "core/settings.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// FileSys namespace
+
+namespace FileSys {
+
+Archive_SaveData::Archive_SaveData(const std::string& mount_point, u64 program_id) 
+        : DiskArchive(mount_point + Common::StringFromFormat("%016X", program_id) + DIR_SEP) {
+    LOG_INFO(Service_FS, "Directory %s set as SaveData.", this->mount_point.c_str());
+}
+
+bool Archive_SaveData::Initialize() {
+    if (!FileUtil::CreateFullPath(mount_point)) {
+        LOG_ERROR(Service_FS, "Unable to create SaveData path.");
+        return false;
+    }
+
+    return true;
+}
+
+} // namespace FileSys
diff --git a/src/core/file_sys/archive_savedata.h b/src/core/file_sys/archive_savedata.h
new file mode 100644
index 00000000..b3e56113
--- /dev/null
+++ b/src/core/file_sys/archive_savedata.h
@@ -0,0 +1,32 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+
+#include "core/file_sys/disk_archive.h"
+#include "core/loader/loader.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// FileSys namespace
+
+namespace FileSys {
+
+/// File system interface to the SaveData archive
+class Archive_SaveData final : public DiskArchive {
+public:
+    Archive_SaveData(const std::string& mount_point, u64 program_id);
+
+    /**
+     * Initialize the archive.
+     * @return CreateSaveDataResult AlreadyExists if the SaveData folder already exists,
+     * Success if it was created properly and Failure if there was any error
+     */
+    bool Initialize();
+
+    std::string GetName() const override { return "SaveData"; }
+};
+
+} // namespace FileSys
diff --git a/src/core/file_sys/archive_sdmc.cpp b/src/core/file_sys/archive_sdmc.cpp
index 9d58668e..dccdf7f6 100644
--- a/src/core/file_sys/archive_sdmc.cpp
+++ b/src/core/file_sys/archive_sdmc.cpp
@@ -8,8 +8,7 @@
 #include "common/file_util.h"
 
 #include "core/file_sys/archive_sdmc.h"
-#include "core/file_sys/directory_sdmc.h"
-#include "core/file_sys/file_sdmc.h"
+#include "core/file_sys/disk_archive.h"
 #include "core/settings.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -17,18 +16,10 @@
 
 namespace FileSys {
 
-Archive_SDMC::Archive_SDMC(const std::string& mount_point) {
-    this->mount_point = mount_point;
+Archive_SDMC::Archive_SDMC(const std::string& mount_point) : DiskArchive(mount_point) {
     LOG_INFO(Service_FS, "Directory %s set as SDMC.", mount_point.c_str());
 }
 
-Archive_SDMC::~Archive_SDMC() {
-}
-
-/**
- * Initialize the archive.
- * @return true if it initialized successfully
- */
 bool Archive_SDMC::Initialize() {
     if (!Settings::values.use_virtual_sd) {
         LOG_WARNING(Service_FS, "SDMC disabled by config.");
@@ -43,74 +34,4 @@ bool Archive_SDMC::Initialize() {
     return true;
 }
 
-/**
- * Open a file specified by its path, using the specified mode
- * @param path Path relative to the archive
- * @param mode Mode to open the file with
- * @return Opened file, or nullptr
- */
-std::unique_ptr<FileBackend> Archive_SDMC::OpenFile(const Path& path, const Mode mode) const {
-    LOG_DEBUG(Service_FS, "called path=%s mode=%u", path.DebugStr().c_str(), mode.hex);
-    File_SDMC* file = new File_SDMC(this, path, mode);
-    if (!file->Open())
-        return nullptr;
-    return std::unique_ptr<FileBackend>(file);
-}
-
-/**
- * Delete a file specified by its path
- * @param path Path relative to the archive
- * @return Whether the file could be deleted
- */
-bool Archive_SDMC::DeleteFile(const FileSys::Path& path) const {
-    return FileUtil::Delete(GetMountPoint() + path.AsString());
-}
-
-bool Archive_SDMC::RenameFile(const FileSys::Path& src_path, const FileSys::Path& dest_path) const {
-    return FileUtil::Rename(GetMountPoint() + src_path.AsString(), GetMountPoint() + dest_path.AsString());
-}
-
-/**
- * Delete a directory specified by its path
- * @param path Path relative to the archive
- * @return Whether the directory could be deleted
- */
-bool Archive_SDMC::DeleteDirectory(const FileSys::Path& path) const {
-    return FileUtil::DeleteDir(GetMountPoint() + path.AsString());
-}
-
-/**
- * Create a directory specified by its path
- * @param path Path relative to the archive
- * @return Whether the directory could be created
- */
-bool Archive_SDMC::CreateDirectory(const Path& path) const {
-    return FileUtil::CreateDir(GetMountPoint() + path.AsString());
-}
-
-bool Archive_SDMC::RenameDirectory(const FileSys::Path& src_path, const FileSys::Path& dest_path) const {
-    return FileUtil::Rename(GetMountPoint() + src_path.AsString(), GetMountPoint() + dest_path.AsString());
-}
-
-/**
- * Open a directory specified by its path
- * @param path Path relative to the archive
- * @return Opened directory, or nullptr
- */
-std::unique_ptr<DirectoryBackend> Archive_SDMC::OpenDirectory(const Path& path) const {
-    LOG_DEBUG(Service_FS, "called path=%s", path.DebugStr().c_str());
-    Directory_SDMC* directory = new Directory_SDMC(this, path);
-    if (!directory->Open())
-        return nullptr;
-    return std::unique_ptr<DirectoryBackend>(directory);
-}
-
-/**
- * Getter for the path used for this Archive
- * @return Mount point of that passthrough archive
- */
-std::string Archive_SDMC::GetMountPoint() const {
-    return mount_point;
-}
-
 } // namespace FileSys
diff --git a/src/core/file_sys/archive_sdmc.h b/src/core/file_sys/archive_sdmc.h
index 05904524..c84c6948 100644
--- a/src/core/file_sys/archive_sdmc.h
+++ b/src/core/file_sys/archive_sdmc.h
@@ -6,7 +6,7 @@
 
 #include "common/common_types.h"
 
-#include "core/file_sys/archive_backend.h"
+#include "core/file_sys/disk_archive.h"
 #include "core/loader/loader.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -15,10 +15,9 @@
 namespace FileSys {
 
 /// File system interface to the SDMC archive
-class Archive_SDMC final : public ArchiveBackend {
+class Archive_SDMC final : public DiskArchive {
 public:
     Archive_SDMC(const std::string& mount_point);
-    ~Archive_SDMC() override;
 
     /**
      * Initialize the archive.
@@ -27,67 +26,6 @@ public:
     bool Initialize();
 
     std::string GetName() const override { return "SDMC"; }
-
-    /**
-     * Open a file specified by its path, using the specified mode
-     * @param path Path relative to the archive
-     * @param mode Mode to open the file with
-     * @return Opened file, or nullptr
-     */
-    std::unique_ptr<FileBackend> OpenFile(const Path& path, const Mode mode) const override;
-
-    /**
-     * Delete a file specified by its path
-     * @param path Path relative to the archive
-     * @return Whether the file could be deleted
-     */
-    bool DeleteFile(const FileSys::Path& path) const override;
-
-    /**
-     * Rename a File specified by its path
-     * @param src_path Source path relative to the archive
-     * @param dest_path Destination path relative to the archive
-     * @return Whether rename succeeded
-     */
-    bool RenameFile(const FileSys::Path& src_path, const FileSys::Path& dest_path) const override;
-
-    /**
-     * Delete a directory specified by its path
-     * @param path Path relative to the archive
-     * @return Whether the directory could be deleted
-     */
-    bool DeleteDirectory(const FileSys::Path& path) const override;
-
-    /**
-     * Create a directory specified by its path
-     * @param path Path relative to the archive
-     * @return Whether the directory could be created
-     */
-    bool CreateDirectory(const Path& path) const override;
-
-    /**
-     * Rename a Directory specified by its path
-     * @param src_path Source path relative to the archive
-     * @param dest_path Destination path relative to the archive
-     * @return Whether rename succeeded
-     */
-    bool RenameDirectory(const FileSys::Path& src_path, const FileSys::Path& dest_path) const override;
-
-    /**
-     * Open a directory specified by its path
-     * @param path Path relative to the archive
-     * @return Opened directory, or nullptr
-     */
-    std::unique_ptr<DirectoryBackend> OpenDirectory(const Path& path) const override;
-
-    /**
-     * Getter for the path used for this Archive
-     * @return Mount point of that passthrough archive
-     */
-    std::string GetMountPoint() const;
-
-private:
-    std::string mount_point;
 };
 
 } // namespace FileSys
diff --git a/src/core/file_sys/directory_sdmc.cpp b/src/core/file_sys/directory_sdmc.cpp
deleted file mode 100644
index 51978764..00000000
--- a/src/core/file_sys/directory_sdmc.cpp
+++ /dev/null
@@ -1,88 +0,0 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2
-// Refer to the license.txt file included.
-
-#include <sys/stat.h>
-
-#include "common/common_types.h"
-#include "common/file_util.h"
-
-#include "core/file_sys/directory_sdmc.h"
-#include "core/file_sys/archive_sdmc.h"
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-// FileSys namespace
-
-namespace FileSys {
-
-Directory_SDMC::Directory_SDMC(const Archive_SDMC* archive, const Path& path) {
-    // TODO(Link Mauve): normalize path into an absolute path without "..", it can currently bypass
-    // the root directory we set while opening the archive.
-    // For example, opening /../../usr/bin can give the emulated program your installed programs.
-    this->path = archive->GetMountPoint() + path.AsString();
-
-}
-
-Directory_SDMC::~Directory_SDMC() {
-    Close();
-}
-
-bool Directory_SDMC::Open() {
-    if (!FileUtil::IsDirectory(path))
-        return false;
-    FileUtil::ScanDirectoryTree(path, directory);
-    children_iterator = directory.children.begin();
-    return true;
-}
-
-/**
- * List files contained in the directory
- * @param count Number of entries to return at once in entries
- * @param entries Buffer to read data into
- * @return Number of entries listed
- */
-u32 Directory_SDMC::Read(const u32 count, Entry* entries) {
-    u32 entries_read = 0;
-
-    while (entries_read < count && children_iterator != directory.children.cend()) {
-        const FileUtil::FSTEntry& file = *children_iterator;
-        const std::string& filename = file.virtualName;
-        Entry& entry = entries[entries_read];
-
-        LOG_TRACE(Service_FS, "File %s: size=%llu dir=%d", filename.c_str(), file.size, file.isDirectory);
-
-        // TODO(Link Mauve): use a proper conversion to UTF-16.
-        for (size_t j = 0; j < FILENAME_LENGTH; ++j) {
-            entry.filename[j] = filename[j];
-            if (!filename[j])
-                break;
-        }
-
-        FileUtil::SplitFilename83(filename, entry.short_name, entry.extension);
-
-        entry.is_directory = file.isDirectory;
-        entry.is_hidden = (filename[0] == '.');
-        entry.is_read_only = 0;
-        entry.file_size = file.size;
-
-        // We emulate a SD card where the archive bit has never been cleared, as it would be on
-        // most user SD cards.
-        // Some homebrews (blargSNES for instance) are known to mistakenly use the archive bit as a
-        // file bit.
-        entry.is_archive = !file.isDirectory;
-
-        ++entries_read;
-        ++children_iterator;
-    }
-    return entries_read;
-}
-
-/**
- * Close the directory
- * @return true if the directory closed correctly
- */
-bool Directory_SDMC::Close() const {
-    return true;
-}
-
-} // namespace FileSys
diff --git a/src/core/file_sys/directory_sdmc.h b/src/core/file_sys/directory_sdmc.h
deleted file mode 100644
index 407a256e..00000000
--- a/src/core/file_sys/directory_sdmc.h
+++ /dev/null
@@ -1,55 +0,0 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include "common/common_types.h"
-#include "common/file_util.h"
-
-#include "core/file_sys/directory_backend.h"
-#include "core/file_sys/archive_sdmc.h"
-#include "core/loader/loader.h"
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-// FileSys namespace
-
-namespace FileSys {
-
-class Directory_SDMC final : public DirectoryBackend {
-public:
-    Directory_SDMC();
-    Directory_SDMC(const Archive_SDMC* archive, const Path& path);
-    ~Directory_SDMC() override;
-
-    /**
-    * Open the directory
-    * @return true if the directory opened correctly
-    */
-    bool Open() override;
-
-    /**
-     * List files contained in the directory
-     * @param count Number of entries to return at once in entries
-     * @param entries Buffer to read data into
-     * @return Number of entries listed
-     */
-    u32 Read(const u32 count, Entry* entries) override;
-
-    /**
-     * Close the directory
-     * @return true if the directory closed correctly
-     */
-    bool Close() const override;
-
-private:
-    std::string path;
-    u32 total_entries_in_directory;
-    FileUtil::FSTEntry directory;
-
-    // We need to remember the last entry we returned, so a subsequent call to Read will continue
-    // from the next one.  This iterator will always point to the next unread entry.
-    std::vector<FileUtil::FSTEntry>::iterator children_iterator;
-};
-
-} // namespace FileSys
diff --git a/src/core/file_sys/disk_archive.cpp b/src/core/file_sys/disk_archive.cpp
new file mode 100644
index 00000000..eabf5805
--- /dev/null
+++ b/src/core/file_sys/disk_archive.cpp
@@ -0,0 +1,167 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#include <sys/stat.h>
+
+#include "common/common_types.h"
+#include "common/file_util.h"
+
+#include "core/file_sys/disk_archive.h"
+#include "core/settings.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// FileSys namespace
+
+namespace FileSys {
+
+std::unique_ptr<FileBackend> DiskArchive::OpenFile(const Path& path, const Mode mode) const {
+    LOG_DEBUG(Service_FS, "called path=%s mode=%01X", path.DebugStr().c_str(), mode.hex);
+    DiskFile* file = new DiskFile(this, path, mode);
+    if (!file->Open())
+        return nullptr;
+    return std::unique_ptr<FileBackend>(file);
+}
+
+bool DiskArchive::DeleteFile(const FileSys::Path& path) const {
+    return FileUtil::Delete(GetMountPoint() + path.AsString());
+}
+
+bool DiskArchive::RenameFile(const FileSys::Path& src_path, const FileSys::Path& dest_path) const {
+    return FileUtil::Rename(GetMountPoint() + src_path.AsString(), GetMountPoint() + dest_path.AsString());
+}
+
+bool DiskArchive::DeleteDirectory(const FileSys::Path& path) const {
+    return FileUtil::DeleteDir(GetMountPoint() + path.AsString());
+}
+
+bool DiskArchive::CreateDirectory(const Path& path) const {
+    return FileUtil::CreateDir(GetMountPoint() + path.AsString());
+}
+
+bool DiskArchive::RenameDirectory(const FileSys::Path& src_path, const FileSys::Path& dest_path) const {
+    return FileUtil::Rename(GetMountPoint() + src_path.AsString(), GetMountPoint() + dest_path.AsString());
+}
+
+std::unique_ptr<DirectoryBackend> DiskArchive::OpenDirectory(const Path& path) const {
+    LOG_DEBUG(Service_FS, "called path=%s", path.DebugStr().c_str());
+    DiskDirectory* directory = new DiskDirectory(this, path);
+    if (!directory->Open())
+        return nullptr;
+    return std::unique_ptr<DirectoryBackend>(directory);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+DiskFile::DiskFile(const DiskArchive* archive, const Path& path, const Mode mode) {
+    // TODO(Link Mauve): normalize path into an absolute path without "..", it can currently bypass
+    // the root directory we set while opening the archive.
+    // For example, opening /../../etc/passwd can give the emulated program your users list.
+    this->path = archive->GetMountPoint() + path.AsString();
+    this->mode.hex = mode.hex;
+    this->archive = archive;
+}
+
+bool DiskFile::Open() {
+    if (!mode.create_flag && !FileUtil::Exists(path)) {
+        LOG_ERROR(Service_FS, "Non-existing file %s can’t be open without mode create.", path.c_str());
+        return false;
+    }
+
+    std::string mode_string;
+    if (mode.create_flag)
+        mode_string = "w+";
+    else if (mode.write_flag)
+        mode_string = "r+"; // Files opened with Write access can be read from
+    else if (mode.read_flag)
+        mode_string = "r";
+
+    // Open the file in binary mode, to avoid problems with CR/LF on Windows systems
+    mode_string += "b";
+
+    file = new FileUtil::IOFile(path, mode_string.c_str());
+    return true;
+}
+
+size_t DiskFile::Read(const u64 offset, const u32 length, u8* buffer) const {
+    file->Seek(offset, SEEK_SET);
+    return file->ReadBytes(buffer, length);
+}
+
+size_t DiskFile::Write(const u64 offset, const u32 length, const u32 flush, const u8* buffer) const {
+    file->Seek(offset, SEEK_SET);
+    size_t written = file->WriteBytes(buffer, length);
+    if (flush)
+        file->Flush();
+    return written;
+}
+
+size_t DiskFile::GetSize() const {
+    return static_cast<size_t>(file->GetSize());
+}
+
+bool DiskFile::SetSize(const u64 size) const {
+    file->Resize(size);
+    file->Flush();
+    return true;
+}
+
+bool DiskFile::Close() const {
+    return file->Close();
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+DiskDirectory::DiskDirectory(const DiskArchive* archive, const Path& path) {
+    // TODO(Link Mauve): normalize path into an absolute path without "..", it can currently bypass
+    // the root directory we set while opening the archive.
+    // For example, opening /../../usr/bin can give the emulated program your installed programs.
+    this->path = archive->GetMountPoint() + path.AsString();
+    this->archive = archive;
+}
+
+bool DiskDirectory::Open() {
+    if (!FileUtil::IsDirectory(path))
+        return false;
+    FileUtil::ScanDirectoryTree(path, directory);
+    children_iterator = directory.children.begin();
+    return true;
+}
+
+u32 DiskDirectory::Read(const u32 count, Entry* entries) {
+    u32 entries_read = 0;
+
+    while (entries_read < count && children_iterator != directory.children.cend()) {
+        const FileUtil::FSTEntry& file = *children_iterator;
+        const std::string& filename = file.virtualName;
+        Entry& entry = entries[entries_read];
+
+        LOG_TRACE(Service_FS, "File %s: size=%llu dir=%d", filename.c_str(), file.size, file.isDirectory);
+
+        // TODO(Link Mauve): use a proper conversion to UTF-16.
+        for (size_t j = 0; j < FILENAME_LENGTH; ++j) {
+            entry.filename[j] = filename[j];
+            if (!filename[j])
+                break;
+        }
+
+        FileUtil::SplitFilename83(filename, entry.short_name, entry.extension);
+
+        entry.is_directory = file.isDirectory;
+        entry.is_hidden = (filename[0] == '.');
+        entry.is_read_only = 0;
+        entry.file_size = file.size;
+
+        // We emulate a SD card where the archive bit has never been cleared, as it would be on
+        // most user SD cards.
+        // Some homebrews (blargSNES for instance) are known to mistakenly use the archive bit as a
+        // file bit.
+        entry.is_archive = !file.isDirectory;
+
+        ++entries_read;
+        ++children_iterator;
+    }
+    return entries_read;
+}
+
+} // namespace FileSys
diff --git a/src/core/file_sys/disk_archive.h b/src/core/file_sys/disk_archive.h
new file mode 100644
index 00000000..778c8395
--- /dev/null
+++ b/src/core/file_sys/disk_archive.h
@@ -0,0 +1,101 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+
+#include "core/file_sys/archive_backend.h"
+#include "core/loader/loader.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// FileSys namespace
+
+namespace FileSys {
+
+/**
+ * Helper which implements a backend accessing the host machine's filesystem. 
+ * This should be subclassed by concrete archive types, which will provide the 
+ * base directory on the host filesystem and override any required functionality.
+ */
+class DiskArchive : public ArchiveBackend {
+public:
+    DiskArchive(const std::string& mount_point_) : mount_point(mount_point_) {}
+
+    virtual std::string GetName() const = 0;
+    std::unique_ptr<FileBackend> OpenFile(const Path& path, const Mode mode) const override;
+    bool DeleteFile(const FileSys::Path& path) const override;
+    bool RenameFile(const FileSys::Path& src_path, const FileSys::Path& dest_path) const override;
+    bool DeleteDirectory(const FileSys::Path& path) const override;
+    bool CreateDirectory(const Path& path) const override;
+    bool RenameDirectory(const FileSys::Path& src_path, const FileSys::Path& dest_path) const override;
+    std::unique_ptr<DirectoryBackend> OpenDirectory(const Path& path) const override;
+
+    /**
+     * Getter for the path used for this Archive
+     * @return Mount point of that passthrough archive
+     */
+    const std::string& GetMountPoint() const {
+        return mount_point;
+    }
+
+protected:
+    std::string mount_point;
+};
+
+class DiskFile : public FileBackend {
+public:
+    DiskFile();
+    DiskFile(const DiskArchive* archive, const Path& path, const Mode mode);
+    
+    ~DiskFile() override {
+        Close();
+    }
+
+    bool Open() override;
+    size_t Read(const u64 offset, const u32 length, u8* buffer) const override;
+    size_t Write(const u64 offset, const u32 length, const u32 flush, const u8* buffer) const override;
+    size_t GetSize() const override;
+    bool SetSize(const u64 size) const override;
+    bool Close() const override;
+    
+    void Flush() const override {
+        file->Flush();
+    }
+
+protected:
+    const DiskArchive* archive;
+    std::string path;
+    Mode mode;
+    FileUtil::IOFile* file;
+};
+
+class DiskDirectory : public DirectoryBackend {
+public:
+    DiskDirectory();
+    DiskDirectory(const DiskArchive* archive, const Path& path);
+
+    ~DiskDirectory() override {
+        Close();
+    }
+
+    bool Open() override;
+    u32 Read(const u32 count, Entry* entries) override;
+
+    bool Close() const override {
+        return true;
+    }
+
+protected:
+    const DiskArchive* archive;
+    std::string path;
+    u32 total_entries_in_directory;
+    FileUtil::FSTEntry directory;
+
+    // We need to remember the last entry we returned, so a subsequent call to Read will continue
+    // from the next one.  This iterator will always point to the next unread entry.
+    std::vector<FileUtil::FSTEntry>::iterator children_iterator;
+};
+
+} // namespace FileSys
diff --git a/src/core/file_sys/file_backend.h b/src/core/file_sys/file_backend.h
index 1b81d5fe..539ec731 100644
--- a/src/core/file_sys/file_backend.h
+++ b/src/core/file_sys/file_backend.h
@@ -61,6 +61,11 @@ public:
      * @return true if the file closed correctly
      */
     virtual bool Close() const = 0;
+
+    /**
+     * Flushes the file
+     */
+    virtual void Flush() const = 0;
 };
 
 } // namespace FileSys
diff --git a/src/core/file_sys/file_romfs.h b/src/core/file_sys/file_romfs.h
index 09fa2e7e..32fa6b6d 100644
--- a/src/core/file_sys/file_romfs.h
+++ b/src/core/file_sys/file_romfs.h
@@ -64,6 +64,8 @@ public:
      */
     bool Close() const override;
 
+    void Flush() const override { }
+
 private:
     const Archive_RomFS* archive;
 };
diff --git a/src/core/file_sys/file_sdmc.cpp b/src/core/file_sys/file_sdmc.cpp
deleted file mode 100644
index 46c29900..00000000
--- a/src/core/file_sys/file_sdmc.cpp
+++ /dev/null
@@ -1,110 +0,0 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2
-// Refer to the license.txt file included.
-
-#include <sys/stat.h>
-
-#include "common/common_types.h"
-#include "common/file_util.h"
-
-#include "core/file_sys/file_sdmc.h"
-#include "core/file_sys/archive_sdmc.h"
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-// FileSys namespace
-
-namespace FileSys {
-
-File_SDMC::File_SDMC(const Archive_SDMC* archive, const Path& path, const Mode mode) {
-    // TODO(Link Mauve): normalize path into an absolute path without "..", it can currently bypass
-    // the root directory we set while opening the archive.
-    // For example, opening /../../etc/passwd can give the emulated program your users list.
-    this->path = archive->GetMountPoint() + path.AsString();
-    this->mode.hex = mode.hex;
-}
-
-File_SDMC::~File_SDMC() {
-    Close();
-}
-
-/**
- * Open the file
- * @return true if the file opened correctly
- */
-bool File_SDMC::Open() {
-    if (!mode.create_flag && !FileUtil::Exists(path)) {
-        LOG_ERROR(Service_FS, "Non-existing file %s can’t be open without mode create.", path.c_str());
-        return false;
-    }
-
-    std::string mode_string;
-    if (mode.create_flag)
-        mode_string = "w+";
-    else if (mode.write_flag)
-        mode_string = "r+"; // Files opened with Write access can be read from
-    else if (mode.read_flag)
-        mode_string = "r";
-    
-    // Open the file in binary mode, to avoid problems with CR/LF on Windows systems
-    mode_string += "b";
-
-    file = new FileUtil::IOFile(path, mode_string.c_str());
-    return true;
-}
-
-/**
- * Read data from the file
- * @param offset Offset in bytes to start reading data from
- * @param length Length in bytes of data to read from file
- * @param buffer Buffer to read data into
- * @return Number of bytes read
- */
-size_t File_SDMC::Read(const u64 offset, const u32 length, u8* buffer) const {
-    file->Seek(offset, SEEK_SET);
-    return file->ReadBytes(buffer, length);
-}
-
-/**
- * Write data to the file
- * @param offset Offset in bytes to start writing data to
- * @param length Length in bytes of data to write to file
- * @param flush The flush parameters (0 == do not flush)
- * @param buffer Buffer to read data from
- * @return Number of bytes written
- */
-size_t File_SDMC::Write(const u64 offset, const u32 length, const u32 flush, const u8* buffer) const {
-    file->Seek(offset, SEEK_SET);
-    size_t written = file->WriteBytes(buffer, length);
-    if (flush)
-        file->Flush();
-    return written;
-}
-
-/**
- * Get the size of the file in bytes
- * @return Size of the file in bytes
- */
-size_t File_SDMC::GetSize() const {
-    return static_cast<size_t>(file->GetSize());
-}
-
-/**
- * Set the size of the file in bytes
- * @param size New size of the file
- * @return true if successful
- */
-bool File_SDMC::SetSize(const u64 size) const {
-    file->Resize(size);
-    file->Flush();
-    return true;
-}
-
-/**
- * Close the file
- * @return true if the file closed correctly
- */
-bool File_SDMC::Close() const {
-    return file->Close();
-}
-
-} // namespace FileSys
diff --git a/src/core/file_sys/file_sdmc.h b/src/core/file_sys/file_sdmc.h
deleted file mode 100644
index e0154859..00000000
--- a/src/core/file_sys/file_sdmc.h
+++ /dev/null
@@ -1,75 +0,0 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include "common/common_types.h"
-#include "common/file_util.h"
-
-#include "core/file_sys/file_backend.h"
-#include "core/file_sys/archive_sdmc.h"
-#include "core/loader/loader.h"
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-// FileSys namespace
-
-namespace FileSys {
-
-class File_SDMC final : public FileBackend {
-public:
-    File_SDMC();
-    File_SDMC(const Archive_SDMC* archive, const Path& path, const Mode mode);
-    ~File_SDMC() override;
-
-    /**
-     * Open the file
-     * @return true if the file opened correctly
-     */
-    bool Open() override;
-
-    /**
-     * Read data from the file
-     * @param offset Offset in bytes to start reading data from
-     * @param length Length in bytes of data to read from file
-     * @param buffer Buffer to read data into
-     * @return Number of bytes read
-     */
-    size_t Read(const u64 offset, const u32 length, u8* buffer) const override;
-
-    /**
-     * Write data to the file
-     * @param offset Offset in bytes to start writing data to
-     * @param length Length in bytes of data to write to file
-     * @param flush The flush parameters (0 == do not flush)
-     * @param buffer Buffer to read data from
-     * @return Number of bytes written
-     */
-    size_t Write(const u64 offset, const u32 length, const u32 flush, const u8* buffer) const override;
-
-    /**
-     * Get the size of the file in bytes
-     * @return Size of the file in bytes
-     */
-    size_t GetSize() const override;
-
-    /**
-     * Set the size of the file in bytes
-     * @param size New size of the file
-     * @return true if successful
-     */
-    bool SetSize(const u64 size) const override;
-
-    /**
-     * Close the file
-     * @return true if the file closed correctly
-     */
-    bool Close() const override;
-
-private:
-    std::string path;
-    Mode mode;
-    FileUtil::IOFile* file;
-};
-
-} // namespace FileSys
diff --git a/src/core/hle/kernel/kernel.cpp b/src/core/hle/kernel/kernel.cpp
index 929422b3..6a690e91 100644
--- a/src/core/hle/kernel/kernel.cpp
+++ b/src/core/hle/kernel/kernel.cpp
@@ -14,6 +14,7 @@ namespace Kernel {
 
 Handle g_main_thread = 0;
 ObjectPool g_object_pool;
+u64 g_program_id = 0;
 
 ObjectPool::ObjectPool() {
     next_id = INITIAL_NEXT_ID;
diff --git a/src/core/hle/kernel/kernel.h b/src/core/hle/kernel/kernel.h
index 7e0f15c8..7123485b 100644
--- a/src/core/hle/kernel/kernel.h
+++ b/src/core/hle/kernel/kernel.h
@@ -151,6 +151,12 @@ private:
 extern ObjectPool g_object_pool;
 extern Handle g_main_thread;
 
+/// The ID code of the currently running game
+/// TODO(Subv): This variable should not be here, 
+/// we need a way to store information about the currently loaded application 
+/// for later query during runtime, maybe using the LDR service?
+extern u64 g_program_id;
+
 /// Initialize the kernel
 void Init();
 
diff --git a/src/core/hle/result.h b/src/core/hle/result.h
index 15c4a267..14d2be4a 100644
--- a/src/core/hle/result.h
+++ b/src/core/hle/result.h
@@ -17,6 +17,8 @@
 /// Detailed description of the error. This listing is likely incomplete.
 enum class ErrorDescription : u32 {
     Success = 0,
+    FS_NotFound = 100,
+    FS_NotFormatted = 340, ///< This is used by the FS service when creating a SaveData archive
     InvalidSection = 1000,
     TooLarge = 1001,
     NotAuthorized = 1002,
diff --git a/src/core/hle/service/fs/archive.cpp b/src/core/hle/service/fs/archive.cpp
index caf82d55..9c383473 100644
--- a/src/core/hle/service/fs/archive.cpp
+++ b/src/core/hle/service/fs/archive.cpp
@@ -9,6 +9,7 @@
 #include "common/file_util.h"
 #include "common/math_util.h"
 
+#include "core/file_sys/archive_savedata.h"
 #include "core/file_sys/archive_backend.h"
 #include "core/file_sys/archive_sdmc.h"
 #include "core/file_sys/directory_backend.h"
@@ -135,6 +136,13 @@ public:
             break;
         }
 
+        case FileCommand::Flush:
+        {
+            LOG_TRACE(Service_FS, "Flush");
+            backend->Flush();
+            break;
+        }
+
         // Unknown command...
         default:
             LOG_ERROR(Service_FS, "Unknown command=0x%08X!", cmd);
@@ -220,9 +228,18 @@ ResultVal<ArchiveHandle> OpenArchive(ArchiveIdCode id_code) {
 
     auto itr = id_code_map.find(id_code);
     if (itr == id_code_map.end()) {
+        if (id_code == ArchiveIdCode::SaveData) {
+            // When a SaveData archive is created for the first time, it is not yet formatted
+            // and the save file/directory structure expected by the game has not yet been initialized. 
+            // Returning the NotFormatted error code will signal the game to provision the SaveData archive 
+            // with the files and folders that it expects. 
+            // The FormatSaveData service call will create the SaveData archive when it is called.
+            return ResultCode(ErrorDescription::FS_NotFormatted, ErrorModule::FS,
+                              ErrorSummary::InvalidState, ErrorLevel::Status);
+        }
         // TODO: Verify error against hardware
         return ResultCode(ErrorDescription::NotFound, ErrorModule::FS,
-                ErrorSummary::NotFound, ErrorLevel::Permanent);
+                          ErrorSummary::NotFound, ErrorLevel::Permanent);
     }
 
     // This should never even happen in the first place with 64-bit handles, 
@@ -260,8 +277,8 @@ ResultVal<Handle> OpenFileFromArchive(ArchiveHandle archive_handle, const FileSy
 
     std::unique_ptr<FileSys::FileBackend> backend = archive->backend->OpenFile(path, mode);
     if (backend == nullptr) {
-        return ResultCode(ErrorDescription::NotFound, ErrorModule::FS,
-                          ErrorSummary::NotFound, ErrorLevel::Permanent);
+        return ResultCode(ErrorDescription::FS_NotFound, ErrorModule::FS,
+                          ErrorSummary::NotFound, ErrorLevel::Status);
     }
 
     auto file = std::make_unique<File>(std::move(backend), path);
@@ -366,6 +383,28 @@ ResultVal<Handle> OpenDirectoryFromArchive(ArchiveHandle archive_handle, const F
     return MakeResult<Handle>(handle);
 }
 
+ResultCode FormatSaveData() {
+    // TODO(Subv): Actually wipe the savedata folder after creating or opening it
+
+    // Do not create the archive again if it already exists
+    if (id_code_map.find(ArchiveIdCode::SaveData) != id_code_map.end())
+        return UnimplementedFunction(ErrorModule::FS); // TODO(Subv): Find the correct error code
+
+    // Create the SaveData archive
+    std::string savedata_directory = FileUtil::GetUserPath(D_SAVEDATA_IDX);
+    auto savedata_archive = std::make_unique<FileSys::Archive_SaveData>(savedata_directory,
+        Kernel::g_program_id);
+
+    if (savedata_archive->Initialize()) {
+        CreateArchive(std::move(savedata_archive), ArchiveIdCode::SaveData);
+        return RESULT_SUCCESS;
+    } else {
+        LOG_ERROR(Service_FS, "Can't instantiate SaveData archive with path %s",
+            savedata_archive->GetMountPoint().c_str());
+        return UnimplementedFunction(ErrorModule::FS); // TODO(Subv): Find the proper error code
+    }
+}
+
 /// Initialize archives
 void ArchiveInit() {
     next_handle = 1;
@@ -375,9 +414,9 @@ void ArchiveInit() {
     // archive type is SDMC, so it is the only one getting exposed.
 
     std::string sdmc_directory = FileUtil::GetUserPath(D_SDMC_IDX);
-    auto archive = std::make_unique<FileSys::Archive_SDMC>(sdmc_directory);
-    if (archive->Initialize())
-        CreateArchive(std::move(archive), ArchiveIdCode::SDMC);
+    auto sdmc_archive = std::make_unique<FileSys::Archive_SDMC>(sdmc_directory);
+    if (sdmc_archive->Initialize())
+        CreateArchive(std::move(sdmc_archive), ArchiveIdCode::SDMC);
     else
         LOG_ERROR(Service_FS, "Can't instantiate SDMC archive with path %s", sdmc_directory.c_str());
 }
diff --git a/src/core/hle/service/fs/archive.h b/src/core/hle/service/fs/archive.h
index a38de92e..a128276b 100644
--- a/src/core/hle/service/fs/archive.h
+++ b/src/core/hle/service/fs/archive.h
@@ -109,6 +109,12 @@ ResultCode RenameDirectoryBetweenArchives(ArchiveHandle src_archive_handle, cons
  */
 ResultVal<Handle> OpenDirectoryFromArchive(ArchiveHandle archive_handle, const FileSys::Path& path);
 
+/**
+ * Creates a blank SaveData archive.
+ * @return ResultCode 0 on success or the corresponding code on error
+ */
+ResultCode FormatSaveData();
+
 /// Initialize archives
 void ArchiveInit();
 
diff --git a/src/core/hle/service/fs/fs_user.cpp b/src/core/hle/service/fs/fs_user.cpp
index 0f75d5e3..f99d84b2 100644
--- a/src/core/hle/service/fs/fs_user.cpp
+++ b/src/core/hle/service/fs/fs_user.cpp
@@ -3,11 +3,11 @@
 // Refer to the license.txt file included.
 
 #include "common/common.h"
+#include "common/file_util.h"
 #include "common/scope_exit.h"
-
 #include "common/string_util.h"
-#include "core/hle/service/fs/archive.h"
 #include "core/hle/result.h"
+#include "core/hle/service/fs/archive.h"
 #include "core/hle/service/fs/fs_user.h"
 #include "core/settings.h"
 
@@ -50,9 +50,7 @@ static void Initialize(Service::Interface* self) {
 static void OpenFile(Service::Interface* self) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
 
-    // TODO(Link Mauve): cmd_buff[2], aka archive handle lower word, isn't used according to
-    // 3dmoo's or ctrulib's implementations.  Triple check if it's really the case.
-    Handle archive_handle = static_cast<Handle>(cmd_buff[3]);
+    ArchiveHandle archive_handle = MakeArchiveHandle(cmd_buff[2], cmd_buff[3]);
     auto filename_type    = static_cast<FileSys::LowPathType>(cmd_buff[4]);
     u32 filename_size     = cmd_buff[5];
     FileSys::Mode mode; mode.hex = cmd_buff[6];
@@ -398,6 +396,36 @@ static void IsSdmcDetected(Service::Interface* self) {
     LOG_DEBUG(Service_FS, "called");
 }
 
+/**
+ * FS_User::FormatSaveData service function
+ *  Inputs:
+ *  Outputs:
+ *      1 : Result of function, 0 on success, otherwise error code
+ */
+static void FormatSaveData(Service::Interface* self) {
+    u32* cmd_buff = Kernel::GetCommandBuffer();
+    LOG_DEBUG(Service_FS, "(STUBBED)");
+
+    // TODO(Subv): Find out what the inputs and outputs of this function are
+
+    cmd_buff[1] = FormatSaveData().raw;
+}
+
+/**
+ * FS_User::FormatThisUserSaveData service function
+ *  Inputs:
+ *  Outputs:
+ *      1 : Result of function, 0 on success, otherwise error code
+ */
+static void FormatThisUserSaveData(Service::Interface* self) {
+    u32* cmd_buff = Kernel::GetCommandBuffer();
+    LOG_DEBUG(Service_FS, "(STUBBED)");
+
+    // TODO(Subv): Find out what the inputs and outputs of this function are
+
+    cmd_buff[1] = FormatSaveData().raw;
+}
+
 const FSUserInterface::FunctionInfo FunctionTable[] = {
     {0x000100C6, nullptr,               "Dummy1"},
     {0x040100C4, nullptr,               "Control"},
@@ -415,7 +443,7 @@ const FSUserInterface::FunctionInfo FunctionTable[] = {
     {0x080C00C2, OpenArchive,           "OpenArchive"},
     {0x080D0144, nullptr,               "ControlArchive"},
     {0x080E0080, CloseArchive,          "CloseArchive"},
-    {0x080F0180, nullptr,               "FormatThisUserSaveData"},
+    {0x080F0180, FormatThisUserSaveData,"FormatThisUserSaveData"},
     {0x08100200, nullptr,               "CreateSystemSaveData"},
     {0x08110040, nullptr,               "DeleteSystemSaveData"},
     {0x08120080, nullptr,               "GetFreeBytes"},
@@ -476,7 +504,7 @@ const FSUserInterface::FunctionInfo FunctionTable[] = {
     {0x08490040, nullptr,               "GetArchiveResource"},
     {0x084A0002, nullptr,               "ExportIntegrityVerificationSeed"},
     {0x084B0002, nullptr,               "ImportIntegrityVerificationSeed"},
-    {0x084C0242, nullptr,               "FormatSaveData"},
+    {0x084C0242, FormatSaveData,        "FormatSaveData"},
     {0x084D0102, nullptr,               "GetLegacySubBannerData"},
     {0x084E0342, nullptr,               "UpdateSha256Context"},
     {0x084F0102, nullptr,               "ReadSpecialFile"},
diff --git a/src/core/loader/loader.cpp b/src/core/loader/loader.cpp
index 463dacca..480274d2 100644
--- a/src/core/loader/loader.cpp
+++ b/src/core/loader/loader.cpp
@@ -74,6 +74,7 @@ ResultStatus LoadFile(const std::string& filename) {
 
         // Load application and RomFS
         if (ResultStatus::Success == app_loader.Load()) {
+            Kernel::g_program_id = app_loader.GetProgramId();
             Service::FS::CreateArchive(std::make_unique<FileSys::Archive_RomFS>(app_loader), Service::FS::ArchiveIdCode::RomFS);
             return ResultStatus::Success;
         }
diff --git a/src/core/loader/ncch.cpp b/src/core/loader/ncch.cpp
index ba9ba00c..4d23656e 100644
--- a/src/core/loader/ncch.cpp
+++ b/src/core/loader/ncch.cpp
@@ -315,4 +315,8 @@ ResultStatus AppLoader_NCCH::ReadRomFS(std::vector<u8>& buffer) const {
     return ResultStatus::Error;
 }
 
+u64 AppLoader_NCCH::GetProgramId() const {
+    return *reinterpret_cast<u64 const*>(&ncch_header.program_id[0]);
+}
+
 } // namespace Loader
diff --git a/src/core/loader/ncch.h b/src/core/loader/ncch.h
index 03116add..2fe2a7d8 100644
--- a/src/core/loader/ncch.h
+++ b/src/core/loader/ncch.h
@@ -191,6 +191,12 @@ public:
      */
     ResultStatus ReadRomFS(std::vector<u8>& buffer) const override;
 
+    /*
+     * Gets the program id from the NCCH header
+     * @return u64 Program id
+     */
+    u64 GetProgramId() const;
+
 private:
 
     /**