IOS/KD/VFF: Implement reading from VFF

Source/Core/Core/IOS/Network/KD/NetKDRequest.cpp

@@ -616,8 +616,8 @@ NWC24::ErrorCode NetKDRequestDevice::KDDownload(const u16 entry_index,
     }
   }
 
-  NWC24::ErrorCode reply = IOS::HLE::NWC24::OpenVFF(m_dl_list.GetVFFPath(entry_index), content_name,
+  NWC24::ErrorCode reply = IOS::HLE::NWC24::WriteToVFF(m_dl_list.GetVFFPath(entry_index),
-                                                    m_ios.GetFS(), file_data);
+                                                       content_name, m_ios.GetFS(), file_data);
 
   if (reply != NWC24::WC24_OK)
   {

Source/Core/Core/IOS/Network/KD/VFF/VFFUtil.cpp

@@ -237,6 +237,48 @@ static ErrorCode WriteFile(const std::string& filename, const std::vector<u8>& t
   return WC24_OK;
 }
 
+static ErrorCode ReadFile(const std::string& filename, std::vector<u8>& out)
+{
+  FIL src{};
+  const auto open_error_code = f_open(&src, filename.c_str(), FA_READ);
+  if (open_error_code != FR_OK)
+  {
+    ERROR_LOG_FMT(IOS_WC24, "Failed to open file {} in VFF", filename);
+    return WC24_ERR_FILE_OPEN;
+  }
+
+  Common::ScopeGuard vff_close_guard{[&] { f_close(&src); }};
+
+  u32 size = static_cast<u32>(out.size());
+  u32 read_size{};
+  const auto read_error_code = f_read(&src, out.data(), size, &read_size);
+  if (read_error_code != FR_OK)
+  {
+    ERROR_LOG_FMT(IOS_WC24, "Failed to read file {} in VFF: {}", filename,
+                  static_cast<u32>(read_error_code));
+    return WC24_ERR_FILE_READ;
+  }
+
+  if (read_size != size)
+  {
+    ERROR_LOG_FMT(IOS_WC24, "Failed to read bytes of file {} to VFF ({} != {})", filename,
+                  read_size, size);
+    return WC24_ERR_FILE_READ;
+  }
+
+  // As prior operations did not fail, dismiss the guard and handle a potential error with f_close.
+  vff_close_guard.Dismiss();
+
+  const auto close_error_code = f_close(&src);
+  if (close_error_code != FR_OK)
+  {
+    ERROR_LOG_FMT(IOS_WC24, "Failed to close file {} in VFF", filename);
+    return WC24_ERR_FILE_CLOSE;
+  }
+
+  return WC24_OK;
+}
+
 namespace
 {
 class VffFatFsCallbacks : public Common::FatFsCallbacks
@@ -258,7 +300,7 @@ public:
 };
 }  // namespace
 
-ErrorCode OpenVFF(const std::string& path, const std::string& filename,
+ErrorCode WriteToVFF(const std::string& path, const std::string& filename,
                      const std::shared_ptr<FS::FileSystem>& fs, const std::vector<u8>& data)
 {
   VffFatFsCallbacks callbacks;
@@ -286,6 +328,8 @@ ErrorCode OpenVFF(const std::string& path, const std::string& filename,
       return;
     }
 
+    Common::ScopeGuard unmount_guard{[] { f_unmount(""); }};
+
     const FRESULT vff_mount_error_code = vff_mount(callbacks.m_vff, &fatfs);
     if (vff_mount_error_code != FR_OK)
     {
@@ -295,8 +339,6 @@ ErrorCode OpenVFF(const std::string& path, const std::string& filename,
       return;
     }
 
-    Common::ScopeGuard unmount_guard{[] { f_unmount(""); }};
-
     const auto write_error_code = WriteFile(filename, data);
     if (write_error_code != WC24_OK)
     {
@@ -312,4 +354,108 @@ ErrorCode OpenVFF(const std::string& path, const std::string& filename,
 
   return return_value;
 }
+
+ErrorCode ReadFromVFF(const std::string& path, const std::string& filename,
+                      const std::shared_ptr<FS::FileSystem>& fs, std::vector<u8>& out)
+{
+  VffFatFsCallbacks callbacks;
+  ErrorCode return_value;
+  Common::RunInFatFsContext(callbacks, [&]() {
+    auto temp = fs->OpenFile(PID_KD, PID_KD, path, FS::Mode::ReadWrite);
+    if (!temp)
+    {
+      ERROR_LOG_FMT(IOS_WC24, "Failed to open VFF at: {}", path);
+      return_value = WC24_ERR_NOT_FOUND;
+      return;
+    }
+
+    callbacks.m_vff = &*temp;
+
+    FATFS fatfs{};
+    const FRESULT fatfs_mount_error_code = f_mount(&fatfs, "", 0);
+    if (fatfs_mount_error_code != FR_OK)
+    {
+      // The VFF is most likely broken.
+      ERROR_LOG_FMT(IOS_WC24, "Failed to mount VFF at: {}", path);
+      return_value = WC24_ERR_BROKEN;
+      return;
+    }
+
+    Common::ScopeGuard unmount_guard{[] { f_unmount(""); }};
+
+    const FRESULT vff_mount_error_code = vff_mount(callbacks.m_vff, &fatfs);
+    if (vff_mount_error_code != FR_OK)
+    {
+      // The VFF is most likely broken.
+      ERROR_LOG_FMT(IOS_WC24, "Failed to mount VFF at: {}", path);
+      return_value = WC24_ERR_BROKEN;
+      return;
+    }
+
+    const ErrorCode read_error_code = ReadFile(filename, out);
+    if (read_error_code != WC24_OK)
+    {
+      return_value = read_error_code;
+      return;
+    }
+
+    return_value = WC24_OK;
+    return;
+  });
+
+  return return_value;
+}
+
+ErrorCode DeleteFileFromVFF(const std::string& path, const std::string& filename,
+                            const std::shared_ptr<FS::FileSystem>& fs)
+{
+  VffFatFsCallbacks callbacks;
+  ErrorCode return_value;
+  Common::RunInFatFsContext(callbacks, [&]() {
+    auto temp = fs->OpenFile(PID_KD, PID_KD, path, FS::Mode::ReadWrite);
+    if (!temp)
+    {
+      ERROR_LOG_FMT(IOS_WC24, "Failed to open VFF at: {}", path);
+      return_value = WC24_ERR_NOT_FOUND;
+      return;
+    }
+
+    callbacks.m_vff = &*temp;
+
+    FATFS fatfs{};
+    const FRESULT fatfs_mount_error_code = f_mount(&fatfs, "", 0);
+    if (fatfs_mount_error_code != FR_OK)
+    {
+      // The VFF is most likely broken.
+      ERROR_LOG_FMT(IOS_WC24, "Failed to mount VFF at: {}", path);
+      return_value = WC24_ERR_BROKEN;
+      return;
+    }
+
+    Common::ScopeGuard unmount_guard{[] { f_unmount(""); }};
+
+    const FRESULT vff_mount_error_code = vff_mount(callbacks.m_vff, &fatfs);
+    if (vff_mount_error_code != FR_OK)
+    {
+      // The VFF is most likely broken.
+      ERROR_LOG_FMT(IOS_WC24, "Failed to mount VFF at: {}", path);
+      return_value = WC24_ERR_BROKEN;
+      return;
+    }
+
+    const FRESULT unlink_code = f_unlink(filename.c_str());
+    if (unlink_code != FR_OK)
+    {
+      ERROR_LOG_FMT(IOS_WC24, "Failed to delete file {} in VFF at: {} Code: {}", filename, path,
+                    static_cast<u32>(unlink_code));
+      return_value = WC24_ERR_BROKEN;
+      return;
+    }
+
+    return_value = WC24_OK;
+    return;
+  });
+
+  return return_value;
+}
 }  // namespace IOS::HLE::NWC24

Source/Core/Core/IOS/Network/KD/VFF/VFFUtil.h

@@ -22,8 +22,12 @@ namespace NWC24
 constexpr u16 SECTOR_SIZE = 512;
 constexpr u16 VF_LITTLE_ENDIAN = 0xFFFE;
 constexpr u16 VF_BIG_ENDIAN = 0xFEFF;
-ErrorCode OpenVFF(const std::string& path, const std::string& filename,
+ErrorCode WriteToVFF(const std::string& path, const std::string& filename,
                      const std::shared_ptr<FS::FileSystem>& fs, const std::vector<u8>& data);
+ErrorCode ReadFromVFF(const std::string& path, const std::string& filename,
+                      const std::shared_ptr<FS::FileSystem>& fs, std::vector<u8>& out);
+ErrorCode DeleteFileFromVFF(const std::string& path, const std::string& filename,
+                            const std::shared_ptr<FS::FileSystem>& fs);
 
 #pragma pack(push, 1)
 struct VFFHeader final