12 files changed, 605 insertions, 40 deletions

diff --git a/src/core/file_sys/disk_filesystem.cpp b/src/core/file_sys/disk_filesystem.cpp
new file mode 100644
index 000000000..22b17ba04
--- /dev/null
+++ b/src/core/file_sys/disk_filesystem.cpp
@@ -0,0 +1,146 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cstring>
+#include <memory>
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "core/file_sys/disk_filesystem.h"
+#include "core/file_sys/errors.h"
+
+namespace FileSys {
+
+std::string Disk_FileSystem::GetName() const {
+    return "Disk";
+}
+
+ResultVal<std::unique_ptr<StorageBackend>> Disk_FileSystem::OpenFile(const std::string& path,
+                                                                     Mode mode) const {
+    ASSERT_MSG(mode == Mode::Read || mode == Mode::Write, "Other file modes are not supported");
+
+    std::string full_path = base_directory + path;
+    auto file = std::make_shared<FileUtil::IOFile>(full_path, mode == Mode::Read ? "rb" : "wb");
+
+    if (!file->IsOpen()) {
+        return ERROR_PATH_NOT_FOUND;
+    }
+
+    return MakeResult<std::unique_ptr<StorageBackend>>(
+        std::make_unique<Disk_Storage>(std::move(file)));
+}
+
+ResultCode Disk_FileSystem::DeleteFile(const Path& path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(bunnei): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::RenameFile(const Path& src_path, const Path& dest_path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::DeleteDirectory(const Path& path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::DeleteDirectoryRecursively(const Path& path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::CreateFile(const std::string& path, u64 size) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+
+    std::string full_path = base_directory + path;
+    if (size == 0) {
+        FileUtil::CreateEmptyFile(full_path);
+        return RESULT_SUCCESS;
+    }
+
+    FileUtil::IOFile file(full_path, "wb");
+    // Creates a sparse file (or a normal file on filesystems without the concept of sparse files)
+    // We do this by seeking to the right size, then writing a single null byte.
+    if (file.Seek(size - 1, SEEK_SET) && file.WriteBytes("", 1) == 1) {
+        return RESULT_SUCCESS;
+    }
+
+    LOG_ERROR(Service_FS, "Too large file");
+    // TODO(Subv): Find out the correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::CreateDirectory(const Path& path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::RenameDirectory(const Path& src_path, const Path& dest_path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultVal<std::unique_ptr<DirectoryBackend>> Disk_FileSystem::OpenDirectory(
+    const Path& path) const {
+    return MakeResult<std::unique_ptr<DirectoryBackend>>(std::make_unique<Disk_Directory>());
+}
+
+u64 Disk_FileSystem::GetFreeSpaceSize() const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    return 0;
+}
+
+ResultVal<FileSys::EntryType> Disk_FileSystem::GetEntryType(const std::string& path) const {
+    std::string full_path = base_directory + path;
+    if (!FileUtil::Exists(full_path)) {
+        return ERROR_PATH_NOT_FOUND;
+    }
+
+    // TODO(Subv): Find out the EntryType values
+    UNIMPLEMENTED_MSG("Unimplemented GetEntryType");
+}
+
+ResultVal<size_t> Disk_Storage::Read(const u64 offset, const size_t length, u8* buffer) const {
+    LOG_TRACE(Service_FS, "called offset=%llu, length=%zu", offset, length);
+    file->Seek(offset, SEEK_SET);
+    return MakeResult<size_t>(file->ReadBytes(buffer, length));
+}
+
+ResultVal<size_t> Disk_Storage::Write(const u64 offset, const size_t length, const bool flush,
+                                      const u8* buffer) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    file->Seek(offset, SEEK_SET);
+    size_t written = file->WriteBytes(buffer, length);
+    if (flush) {
+        file->Flush();
+    }
+    return MakeResult<size_t>(written);
+}
+
+u64 Disk_Storage::GetSize() const {
+    return file->GetSize();
+}
+
+bool Disk_Storage::SetSize(const u64 size) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    return false;
+}
+
+u32 Disk_Directory::Read(const u32 count, Entry* entries) {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    return 0;
+}
+
+bool Disk_Directory::Close() const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    return true;
+}
+
+} // namespace FileSys
diff --git a/src/core/file_sys/disk_filesystem.h b/src/core/file_sys/disk_filesystem.h
new file mode 100644
index 000000000..53767b949
--- /dev/null
+++ b/src/core/file_sys/disk_filesystem.h
@@ -0,0 +1,66 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <cstddef>
+#include <memory>
+#include <string>
+#include "common/common_types.h"
+#include "common/file_util.h"
+#include "core/file_sys/directory.h"
+#include "core/file_sys/filesystem.h"
+#include "core/file_sys/storage.h"
+#include "core/hle/result.h"
+
+namespace FileSys {
+
+class Disk_FileSystem : public FileSystemBackend {
+public:
+    explicit Disk_FileSystem(std::string base_directory)
+        : base_directory(std::move(base_directory)) {}
+
+    std::string GetName() const override;
+
+    ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const std::string& path,
+                                                        Mode mode) const override;
+    ResultCode DeleteFile(const Path& path) const override;
+    ResultCode RenameFile(const Path& src_path, const Path& dest_path) const override;
+    ResultCode DeleteDirectory(const Path& path) const override;
+    ResultCode DeleteDirectoryRecursively(const Path& path) const override;
+    ResultCode CreateFile(const std::string& path, u64 size) const override;
+    ResultCode CreateDirectory(const Path& path) const override;
+    ResultCode RenameDirectory(const Path& src_path, const Path& dest_path) const override;
+    ResultVal<std::unique_ptr<DirectoryBackend>> OpenDirectory(const Path& path) const override;
+    u64 GetFreeSpaceSize() const override;
+    ResultVal<EntryType> GetEntryType(const std::string& path) const override;
+
+protected:
+    std::string base_directory;
+};
+
+class Disk_Storage : public StorageBackend {
+public:
+    Disk_Storage(std::shared_ptr<FileUtil::IOFile> file) : file(std::move(file)) {}
+
+    ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
+    ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
+    u64 GetSize() const override;
+    bool SetSize(u64 size) const override;
+    bool Close() const override {
+        return false;
+    }
+    void Flush() const override {}
+
+private:
+    std::shared_ptr<FileUtil::IOFile> file;
+};
+
+class Disk_Directory : public DirectoryBackend {
+public:
+    u32 Read(const u32 count, Entry* entries) override;
+    bool Close() const override;
+};
+
+} // namespace FileSys
diff --git a/src/core/file_sys/errors.h b/src/core/file_sys/errors.h
index be3224ef8..0ed7d2a0c 100644
--- a/src/core/file_sys/errors.h
+++ b/src/core/file_sys/errors.h
@@ -10,36 +10,17 @@ namespace FileSys {
 
 namespace ErrCodes {
 enum {
-    RomFSNotFound = 100,
-    ArchiveNotMounted = 101,
-    FileNotFound = 112,
-    PathNotFound = 113,
-    GameCardNotInserted = 141,
-    NotFound = 120,
-    FileAlreadyExists = 180,
-    DirectoryAlreadyExists = 185,
-    AlreadyExists = 190,
-    InvalidOpenFlags = 230,
-    DirectoryNotEmpty = 240,
-    NotAFile = 250,
-    NotFormatted = 340, ///< This is used by the FS service when creating a SaveData archive
-    ExeFSSectionNotFound = 567,
-    CommandNotAllowed = 630,
-    InvalidReadFlag = 700,
-    InvalidPath = 702,
-    WriteBeyondEnd = 705,
-    UnsupportedOpenFlags = 760,
-    IncorrectExeFSReadSize = 761,
-    UnexpectedFileOrDirectory = 770,
+    NotFound = 1,
 };
 }
 
+constexpr ResultCode ERROR_PATH_NOT_FOUND(ErrorModule::FS, ErrCodes::NotFound);
+
 // TODO(bunnei): Replace these with correct errors for Switch OS
 constexpr ResultCode ERROR_INVALID_PATH(ResultCode(-1));
 constexpr ResultCode ERROR_UNSUPPORTED_OPEN_FLAGS(ResultCode(-1));
 constexpr ResultCode ERROR_INVALID_OPEN_FLAGS(ResultCode(-1));
 constexpr ResultCode ERROR_FILE_NOT_FOUND(ResultCode(-1));
-constexpr ResultCode ERROR_PATH_NOT_FOUND(ResultCode(-1));
 constexpr ResultCode ERROR_UNEXPECTED_FILE_OR_DIRECTORY(ResultCode(-1));
 constexpr ResultCode ERROR_DIRECTORY_ALREADY_EXISTS(ResultCode(-1));
 constexpr ResultCode ERROR_FILE_ALREADY_EXISTS(ResultCode(-1));
diff --git a/src/core/file_sys/filesystem.h b/src/core/file_sys/filesystem.h
index 02705506b..94ad2abf2 100644
--- a/src/core/file_sys/filesystem.h
+++ b/src/core/file_sys/filesystem.h
@@ -27,11 +27,14 @@ enum LowPathType : u32 {
     Wchar = 4,
 };
 
-union Mode {
-    u32 hex;
-    BitField<0, 1, u32> read_flag;
-    BitField<1, 1, u32> write_flag;
-    BitField<2, 1, u32> create_flag;
+enum EntryType : u32 {
+    Directory = 0,
+    File = 1,
+};
+
+enum class Mode : u32 {
+    Read = 1,
+    Write = 2,
 };
 
 class Path {
@@ -86,7 +89,7 @@ public:
      * @param size The size of the new file, filled with zeroes
      * @return Result of the operation
      */
-    virtual ResultCode CreateFile(const Path& path, u64 size) const = 0;
+    virtual ResultCode CreateFile(const std::string& path, u64 size) const = 0;
 
     /**
      * Delete a file specified by its path
@@ -138,8 +141,8 @@ public:
      * @param mode Mode to open the file with
      * @return Opened file, or error code
      */
-    virtual ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const Path& path,
-                                                                const Mode& mode) const = 0;
+    virtual ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const std::string& path,
+                                                                Mode mode) const = 0;
 
     /**
      * Open a directory specified by its path
@@ -153,6 +156,12 @@ public:
      * @return The number of free bytes in the archive
      */
     virtual u64 GetFreeSpaceSize() const = 0;
+
+    /**
+     * Get the type of the specified path
+     * @return The type of the specified path or error code
+     */
+    virtual ResultVal<EntryType> GetEntryType(const std::string& path) const = 0;
 };
 
 class FileSystemFactory : NonCopyable {
@@ -174,10 +183,9 @@ public:
     /**
      * Deletes the archive contents and then re-creates the base folder
      * @param path Path to the archive
-     * @param format_info Format information for the new archive
      * @return ResultCode of the operation, 0 on success
      */
-    virtual ResultCode Format(const Path& path, const FileSys::ArchiveFormatInfo& format_info) = 0;
+    virtual ResultCode Format(const Path& path) = 0;
 
     /**
      * Retrieves the format info about the archive with the specified path
diff --git a/src/core/file_sys/program_metadata.cpp b/src/core/file_sys/program_metadata.cpp
new file mode 100644
index 000000000..a6dcebcc3
--- /dev/null
+++ b/src/core/file_sys/program_metadata.cpp
@@ -0,0 +1,114 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cinttypes>
+#include "common/file_util.h"
+#include "common/logging/log.h"
+#include "core/file_sys/program_metadata.h"
+#include "core/loader/loader.h"
+
+namespace FileSys {
+
+Loader::ResultStatus ProgramMetadata::Load(const std::string& file_path) {
+    FileUtil::IOFile file(file_path, "rb");
+    if (!file.IsOpen())
+        return Loader::ResultStatus::Error;
+
+    std::vector<u8> file_data(file.GetSize());
+
+    if (!file.ReadBytes(file_data.data(), file_data.size()))
+        return Loader::ResultStatus::Error;
+
+    Loader::ResultStatus result = Load(file_data);
+    if (result != Loader::ResultStatus::Success)
+        LOG_ERROR(Service_FS, "Failed to load NPDM from file %s!", file_path.c_str());
+
+    return result;
+}
+
+Loader::ResultStatus ProgramMetadata::Load(const std::vector<u8> file_data, size_t offset) {
+    size_t total_size = static_cast<size_t>(file_data.size() - offset);
+    if (total_size < sizeof(Header))
+        return Loader::ResultStatus::Error;
+
+    size_t header_offset = offset;
+    memcpy(&npdm_header, &file_data[offset], sizeof(Header));
+
+    size_t aci_offset = header_offset + npdm_header.aci_offset;
+    size_t acid_offset = header_offset + npdm_header.acid_offset;
+    memcpy(&aci_header, &file_data[aci_offset], sizeof(AciHeader));
+    memcpy(&acid_header, &file_data[acid_offset], sizeof(AcidHeader));
+
+    size_t fac_offset = acid_offset + acid_header.fac_offset;
+    size_t fah_offset = aci_offset + aci_header.fah_offset;
+    memcpy(&acid_file_access, &file_data[fac_offset], sizeof(FileAccessControl));
+    memcpy(&aci_file_access, &file_data[fah_offset], sizeof(FileAccessHeader));
+
+    return Loader::ResultStatus::Success;
+}
+
+bool ProgramMetadata::Is64BitProgram() const {
+    return npdm_header.has_64_bit_instructions;
+}
+
+ProgramAddressSpaceType ProgramMetadata::GetAddressSpaceType() const {
+    return npdm_header.address_space_type;
+}
+
+u8 ProgramMetadata::GetMainThreadPriority() const {
+    return npdm_header.main_thread_priority;
+}
+
+u8 ProgramMetadata::GetMainThreadCore() const {
+    return npdm_header.main_thread_cpu;
+}
+
+u32 ProgramMetadata::GetMainThreadStackSize() const {
+    return npdm_header.main_stack_size;
+}
+
+u64 ProgramMetadata::GetTitleID() const {
+    return aci_header.title_id;
+}
+
+u64 ProgramMetadata::GetFilesystemPermissions() const {
+    return aci_file_access.permissions;
+}
+
+void ProgramMetadata::Print() const {
+    LOG_DEBUG(Service_FS, "Magic:                  %.4s", npdm_header.magic.data());
+    LOG_DEBUG(Service_FS, "Main thread priority:   0x%02x", npdm_header.main_thread_priority);
+    LOG_DEBUG(Service_FS, "Main thread core:       %u", npdm_header.main_thread_cpu);
+    LOG_DEBUG(Service_FS, "Main thread stack size: 0x%x bytes", npdm_header.main_stack_size);
+    LOG_DEBUG(Service_FS, "Process category:       %u", npdm_header.process_category);
+    LOG_DEBUG(Service_FS, "Flags:                  %02x", npdm_header.flags);
+    LOG_DEBUG(Service_FS, " > 64-bit instructions: %s",
+              npdm_header.has_64_bit_instructions ? "YES" : "NO");
+
+    auto address_space = "Unknown";
+    switch (npdm_header.address_space_type) {
+    case ProgramAddressSpaceType::Is64Bit:
+        address_space = "64-bit";
+        break;
+    case ProgramAddressSpaceType::Is32Bit:
+        address_space = "32-bit";
+        break;
+    }
+
+    LOG_DEBUG(Service_FS, " > Address space:       %s\n", address_space);
+
+    // Begin ACID printing (potential perms, signed)
+    LOG_DEBUG(Service_FS, "Magic:                  %.4s", acid_header.magic.data());
+    LOG_DEBUG(Service_FS, "Flags:                  %02x", acid_header.flags);
+    LOG_DEBUG(Service_FS, " > Is Retail:           %s", acid_header.is_retail ? "YES" : "NO");
+    LOG_DEBUG(Service_FS, "Title ID Min:           %016" PRIX64, acid_header.title_id_min);
+    LOG_DEBUG(Service_FS, "Title ID Max:           %016" PRIX64, acid_header.title_id_max);
+    LOG_DEBUG(Service_FS, "Filesystem Access:      %016" PRIX64 "\n", acid_file_access.permissions);
+
+    // Begin ACI0 printing (actual perms, unsigned)
+    LOG_DEBUG(Service_FS, "Magic:                  %.4s", aci_header.magic.data());
+    LOG_DEBUG(Service_FS, "Title ID:               %016" PRIX64, aci_header.title_id);
+    LOG_DEBUG(Service_FS, "Filesystem Access:      %016" PRIX64 "\n", aci_file_access.permissions);
+}
+} // namespace FileSys
diff --git a/src/core/file_sys/program_metadata.h b/src/core/file_sys/program_metadata.h
new file mode 100644
index 000000000..b80a08485
--- /dev/null
+++ b/src/core/file_sys/program_metadata.h
@@ -0,0 +1,154 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <string>
+#include <vector>
+#include "common/bit_field.h"
+#include "common/common_types.h"
+#include "common/swap.h"
+
+namespace Loader {
+enum class ResultStatus;
+}
+
+namespace FileSys {
+
+enum class ProgramAddressSpaceType : u8 {
+    Is64Bit = 1,
+    Is32Bit = 2,
+};
+
+enum class ProgramFilePermission : u64 {
+    MountContent = 1ULL << 0,
+    SaveDataBackup = 1ULL << 5,
+    SdCard = 1ULL << 21,
+    Calibration = 1ULL << 34,
+    Bit62 = 1ULL << 62,
+    Everything = 1ULL << 63,
+};
+
+/**
+ * Helper which implements an interface to parse Program Description Metadata (NPDM)
+ * Data can either be loaded from a file path or with data and an offset into it.
+ */
+class ProgramMetadata {
+public:
+    Loader::ResultStatus Load(const std::string& file_path);
+    Loader::ResultStatus Load(const std::vector<u8> file_data, size_t offset = 0);
+
+    bool Is64BitProgram() const;
+    ProgramAddressSpaceType GetAddressSpaceType() const;
+    u8 GetMainThreadPriority() const;
+    u8 GetMainThreadCore() const;
+    u32 GetMainThreadStackSize() const;
+    u64 GetTitleID() const;
+    u64 GetFilesystemPermissions() const;
+
+    void Print() const;
+
+private:
+    struct Header {
+        std::array<char, 4> magic;
+        std::array<u8, 8> reserved;
+        union {
+            u8 flags;
+
+            BitField<0, 1, u8> has_64_bit_instructions;
+            BitField<1, 3, ProgramAddressSpaceType> address_space_type;
+            BitField<4, 4, u8> reserved_2;
+        };
+        u8 reserved_3;
+        u8 main_thread_priority;
+        u8 main_thread_cpu;
+        std::array<u8, 8> reserved_4;
+        u32_le process_category;
+        u32_le main_stack_size;
+        std::array<u8, 0x10> application_name;
+        std::array<u8, 0x40> reserved_5;
+        u32_le aci_offset;
+        u32_le aci_size;
+        u32_le acid_offset;
+        u32_le acid_size;
+    };
+
+    static_assert(sizeof(Header) == 0x80, "NPDM header structure size is wrong");
+
+    struct AcidHeader {
+        std::array<u8, 0x100> signature;
+        std::array<u8, 0x100> nca_modulus;
+        std::array<char, 4> magic;
+        u32_le nca_size;
+        std::array<u8, 0x4> reserved;
+        union {
+            u32 flags;
+
+            BitField<0, 1, u32> is_retail;
+            BitField<1, 31, u32> flags_unk;
+        };
+        u64_le title_id_min;
+        u64_le title_id_max;
+        u32_le fac_offset;
+        u32_le fac_size;
+        u32_le sac_offset;
+        u32_le sac_size;
+        u32_le kac_offset;
+        u32_le kac_size;
+        INSERT_PADDING_BYTES(0x8);
+    };
+
+    static_assert(sizeof(AcidHeader) == 0x240, "ACID header structure size is wrong");
+
+    struct AciHeader {
+        std::array<char, 4> magic;
+        std::array<u8, 0xC> reserved;
+        u64_le title_id;
+        INSERT_PADDING_BYTES(0x8);
+        u32_le fah_offset;
+        u32_le fah_size;
+        u32_le sac_offset;
+        u32_le sac_size;
+        u32_le kac_offset;
+        u32_le kac_size;
+        INSERT_PADDING_BYTES(0x8);
+    };
+
+    static_assert(sizeof(AciHeader) == 0x40, "ACI0 header structure size is wrong");
+
+#pragma pack(push, 1)
+
+    struct FileAccessControl {
+        u8 version;
+        INSERT_PADDING_BYTES(3);
+        u64_le permissions;
+        std::array<u8, 0x20> unknown;
+    };
+
+    static_assert(sizeof(FileAccessControl) == 0x2C, "FS access control structure size is wrong");
+
+    struct FileAccessHeader {
+        u8 version;
+        INSERT_PADDING_BYTES(3);
+        u64_le permissions;
+        u32_le unk_offset;
+        u32_le unk_size;
+        u32_le unk_offset_2;
+        u32_le unk_size_2;
+    };
+
+    static_assert(sizeof(FileAccessHeader) == 0x1C, "FS access header structure size is wrong");
+
+#pragma pack(pop)
+
+    Header npdm_header;
+    AciHeader aci_header;
+    AcidHeader acid_header;
+
+    FileAccessControl acid_file_access;
+    FileAccessHeader aci_file_access;
+};
+
+} // namespace FileSys
diff --git a/src/core/file_sys/romfs_factory.cpp b/src/core/file_sys/romfs_factory.cpp
index e0de49f05..b21427948 100644
--- a/src/core/file_sys/romfs_factory.cpp
+++ b/src/core/file_sys/romfs_factory.cpp
@@ -23,7 +23,7 @@ ResultVal<std::unique_ptr<FileSystemBackend>> RomFS_Factory::Open(const Path& pa
     return MakeResult<std::unique_ptr<FileSystemBackend>>(std::move(archive));
 }
 
-ResultCode RomFS_Factory::Format(const Path& path, const FileSys::ArchiveFormatInfo& format_info) {
+ResultCode RomFS_Factory::Format(const Path& path) {
     LOG_ERROR(Service_FS, "Unimplemented Format archive %s", GetName().c_str());
     // TODO(bunnei): Find the right error code for this
     return ResultCode(-1);
diff --git a/src/core/file_sys/romfs_factory.h b/src/core/file_sys/romfs_factory.h
index 10ea13966..e0698e642 100644
--- a/src/core/file_sys/romfs_factory.h
+++ b/src/core/file_sys/romfs_factory.h
@@ -23,7 +23,7 @@ public:
         return "ArchiveFactory_RomFS";
     }
     ResultVal<std::unique_ptr<FileSystemBackend>> Open(const Path& path) override;
-    ResultCode Format(const Path& path, const FileSys::ArchiveFormatInfo& format_info) override;
+    ResultCode Format(const Path& path) override;
     ResultVal<ArchiveFormatInfo> GetFormatInfo(const Path& path) const override;
 
 private:
diff --git a/src/core/file_sys/romfs_filesystem.cpp b/src/core/file_sys/romfs_filesystem.cpp
index ca1463d7c..f1f9b4d04 100644
--- a/src/core/file_sys/romfs_filesystem.cpp
+++ b/src/core/file_sys/romfs_filesystem.cpp
@@ -14,8 +14,8 @@ std::string RomFS_FileSystem::GetName() const {
     return "RomFS";
 }
 
-ResultVal<std::unique_ptr<StorageBackend>> RomFS_FileSystem::OpenFile(const Path& path,
-                                                                      const Mode& mode) const {
+ResultVal<std::unique_ptr<StorageBackend>> RomFS_FileSystem::OpenFile(const std::string& path,
+                                                                      Mode mode) const {
     return MakeResult<std::unique_ptr<StorageBackend>>(
         std::make_unique<RomFS_Storage>(romfs_file, data_offset, data_size));
 }
@@ -48,7 +48,7 @@ ResultCode RomFS_FileSystem::DeleteDirectoryRecursively(const Path& path) const
     return ResultCode(-1);
 }
 
-ResultCode RomFS_FileSystem::CreateFile(const Path& path, u64 size) const {
+ResultCode RomFS_FileSystem::CreateFile(const std::string& path, u64 size) const {
     LOG_CRITICAL(Service_FS, "Attempted to create a file in an ROMFS archive (%s).",
                  GetName().c_str());
     // TODO(bunnei): Use correct error code
@@ -79,6 +79,12 @@ u64 RomFS_FileSystem::GetFreeSpaceSize() const {
     return 0;
 }
 
+ResultVal<FileSys::EntryType> RomFS_FileSystem::GetEntryType(const std::string& path) const {
+    LOG_CRITICAL(Service_FS, "Called within an ROMFS archive (path %s).", path.c_str());
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
 ResultVal<size_t> RomFS_Storage::Read(const u64 offset, const size_t length, u8* buffer) const {
     LOG_TRACE(Service_FS, "called offset=%llu, length=%zu", offset, length);
     romfs_file->Seek(data_offset + offset, SEEK_SET);
diff --git a/src/core/file_sys/romfs_filesystem.h b/src/core/file_sys/romfs_filesystem.h
index 900ea567a..cedd70645 100644
--- a/src/core/file_sys/romfs_filesystem.h
+++ b/src/core/file_sys/romfs_filesystem.h
@@ -29,17 +29,18 @@ public:
 
     std::string GetName() const override;
 
-    ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const Path& path,
-                                                        const Mode& mode) const override;
+    ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const std::string& path,
+                                                        Mode mode) const override;
     ResultCode DeleteFile(const Path& path) const override;
     ResultCode RenameFile(const Path& src_path, const Path& dest_path) const override;
     ResultCode DeleteDirectory(const Path& path) const override;
     ResultCode DeleteDirectoryRecursively(const Path& path) const override;
-    ResultCode CreateFile(const Path& path, u64 size) const override;
+    ResultCode CreateFile(const std::string& path, u64 size) const override;
     ResultCode CreateDirectory(const Path& path) const override;
     ResultCode RenameDirectory(const Path& src_path, const Path& dest_path) const override;
     ResultVal<std::unique_ptr<DirectoryBackend>> OpenDirectory(const Path& path) const override;
     u64 GetFreeSpaceSize() const override;
+    ResultVal<EntryType> GetEntryType(const std::string& path) const override;
 
 protected:
     std::shared_ptr<FileUtil::IOFile> romfs_file;
diff --git a/src/core/file_sys/savedata_factory.cpp b/src/core/file_sys/savedata_factory.cpp
new file mode 100644
index 000000000..c3329ce52
--- /dev/null
+++ b/src/core/file_sys/savedata_factory.cpp
@@ -0,0 +1,56 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cinttypes>
+#include <memory>
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "common/string_util.h"
+#include "core/file_sys/disk_filesystem.h"
+#include "core/file_sys/savedata_factory.h"
+#include "core/hle/kernel/process.h"
+
+namespace FileSys {
+
+SaveData_Factory::SaveData_Factory(std::string nand_directory)
+    : nand_directory(std::move(nand_directory)) {}
+
+ResultVal<std::unique_ptr<FileSystemBackend>> SaveData_Factory::Open(const Path& path) {
+    std::string save_directory = GetFullPath();
+    // Return an error if the save data doesn't actually exist.
+    if (!FileUtil::IsDirectory(save_directory)) {
+        // TODO(Subv): Find out correct error code.
+        return ResultCode(-1);
+    }
+
+    auto archive = std::make_unique<Disk_FileSystem>(save_directory);
+    return MakeResult<std::unique_ptr<FileSystemBackend>>(std::move(archive));
+}
+
+ResultCode SaveData_Factory::Format(const Path& path) {
+    LOG_WARNING(Service_FS, "Format archive %s", GetName().c_str());
+    // Create the save data directory.
+    if (!FileUtil::CreateFullPath(GetFullPath())) {
+        // TODO(Subv): Find the correct error code.
+        return ResultCode(-1);
+    }
+
+    return RESULT_SUCCESS;
+}
+
+ResultVal<ArchiveFormatInfo> SaveData_Factory::GetFormatInfo(const Path& path) const {
+    LOG_ERROR(Service_FS, "Unimplemented GetFormatInfo archive %s", GetName().c_str());
+    // TODO(bunnei): Find the right error code for this
+    return ResultCode(-1);
+}
+
+std::string SaveData_Factory::GetFullPath() const {
+    u64 title_id = Kernel::g_current_process->program_id;
+    // TODO(Subv): Somehow obtain this value.
+    u32 user = 0;
+    return Common::StringFromFormat("%ssave/%016" PRIX64 "/%08X/", nand_directory.c_str(), title_id,
+                                    user);
+}
+
+} // namespace FileSys
diff --git a/src/core/file_sys/savedata_factory.h b/src/core/file_sys/savedata_factory.h
new file mode 100644
index 000000000..73a42aab6
--- /dev/null
+++ b/src/core/file_sys/savedata_factory.h
@@ -0,0 +1,33 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <string>
+#include "common/common_types.h"
+#include "core/file_sys/filesystem.h"
+#include "core/hle/result.h"
+
+namespace FileSys {
+
+/// File system interface to the SaveData archive
+class SaveData_Factory final : public FileSystemFactory {
+public:
+    explicit SaveData_Factory(std::string nand_directory);
+
+    std::string GetName() const override {
+        return "SaveData_Factory";
+    }
+    ResultVal<std::unique_ptr<FileSystemBackend>> Open(const Path& path) override;
+    ResultCode Format(const Path& path) override;
+    ResultVal<ArchiveFormatInfo> GetFormatInfo(const Path& path) const override;
+
+private:
+    std::string nand_directory;
+
+    std::string GetFullPath() const;
+};
+
+} // namespace FileSys