Back up part of SYSCONF when switching to emulated BT

This fixes an issue where the Bluetooth info section could be fully
filled up by syncing 5 Wiimotes in passthrough mode then switching to
emulated Bluetooth; emulated Wiimotes were then unable to be used.

The "real" SYSCONF section is now backed up before being replaced with
a blank section that the emulated BT adapter can always fill with 5
Wiimotes without issues.

This backup is restored by the passthrough code, instead of during
the Bluetooth mode switch because this should be done regardless of the
user interface, and even without UI (if the config file is edited
manually).

Source/Core/Common/CommonPaths.h

@@ -120,6 +120,7 @@
 #define WII_STATE "state.dat"
 
 #define WII_SDCARD "sd.raw"
+#define WII_BTDINF_BACKUP "btdinf.bak"
 
 #define WII_SETTING "setting.txt"
 

Source/Core/Core/BootManager.cpp

@@ -35,6 +35,7 @@
 #include "Core/HW/Sram.h"
 #include "Core/HW/WiimoteReal/WiimoteReal.h"
 #include "Core/Host.h"
+#include "Core/IPC_HLE/WII_IPC_HLE_Device_usb_bt_base.h"
 #include "Core/Movie.h"
 #include "Core/NetPlayProto.h"
 #include "VideoCommon/VideoBackendBase.h"
@@ -399,6 +400,8 @@ bool BootCore(const std::string& _rFilename)
     // TODO: remove this if and once Dolphin supports WC24 standby mode.
     SConfig::GetInstance().m_SYSCONF->SetData<u8>("IPL.IDL", 0x00);
     NOTICE_LOG(BOOT, "Disabling WC24 'standby' (shutdown to idle) to avoid hanging on shutdown");
+
+    RestoreBTInfoSection();
   }
 
   // Run the game

Source/Core/Core/IPC_HLE/WII_IPC_HLE_Device_usb_bt_base.cpp

@@ -2,14 +2,56 @@
 // Licensed under GPLv2+
 // Refer to the license.txt file included.
 
-#include "Core/IPC_HLE/WII_IPC_HLE_Device_usb_bt_base.h"
+#include <string>
+#include <vector>
+
 #include "Common/Assert.h"
 #include "Common/CommonFuncs.h"
+#include "Common/CommonPaths.h"
 #include "Common/CommonTypes.h"
+#include "Common/FileUtil.h"
 #include "Common/Logging/Log.h"
 #include "Core/ConfigManager.h"
 #include "Core/Core.h"
 #include "Core/HW/Memmap.h"
+#include "Core/IPC_HLE/WII_IPC_HLE_Device_usb_bt_base.h"
+
+constexpr u16 BT_INFO_SECTION_LENGTH = 0x460;
+
+void BackUpBTInfoSection()
+{
+  const std::string filename = File::GetUserPath(D_SESSION_WIIROOT_IDX) + DIR_SEP WII_BTDINF_BACKUP;
+  if (File::Exists(filename))
+    return;
+  File::IOFile backup(filename, "wb");
+  std::vector<u8> section(BT_INFO_SECTION_LENGTH);
+  if (!SConfig::GetInstance().m_SYSCONF->GetArrayData("BT.DINF", section.data(),
+                                                      static_cast<u16>(section.size())))
+  {
+    ERROR_LOG(WII_IPC_WIIMOTE, "Failed to read source BT.DINF section");
+    return;
+  }
+  if (!backup.WriteBytes(section.data(), section.size()))
+    ERROR_LOG(WII_IPC_WIIMOTE, "Failed to back up BT.DINF section");
+}
+
+void RestoreBTInfoSection()
+{
+  const std::string filename = File::GetUserPath(D_SESSION_WIIROOT_IDX) + DIR_SEP WII_BTDINF_BACKUP;
+  if (!File::Exists(filename))
+    return;
+  File::IOFile backup(filename, "rb");
+  std::vector<u8> section(BT_INFO_SECTION_LENGTH);
+  if (!backup.ReadBytes(section.data(), section.size()))
+  {
+    ERROR_LOG(WII_IPC_WIIMOTE, "Failed to read backed up BT.DINF section");
+    return;
+  }
+  SConfig::GetInstance().m_SYSCONF->SetArrayData("BT.DINF", section.data(),
+                                                 static_cast<u16>(section.size()));
+  SConfig::GetInstance().m_SYSCONF->Save();
+  File::Delete(filename);
+}
 
 IPCCommandResult CWII_IPC_HLE_Device_usb_oh1_57e_305_base::IOCtl(u32 command_address)
 {

Source/Core/Core/IPC_HLE/WII_IPC_HLE_Device_usb_bt_base.h

@@ -7,6 +7,9 @@
 #include "Core/IPC_HLE/WII_IPC_HLE.h"
 #include "Core/IPC_HLE/WII_IPC_HLE_Device.h"
 
+void BackUpBTInfoSection();
+void RestoreBTInfoSection();
+
 class CWII_IPC_HLE_Device_usb_oh1_57e_305_base : public IWII_IPC_HLE_Device
 {
 public:

Source/Core/Core/IPC_HLE/WII_IPC_HLE_Device_usb_bt_emu.cpp

@@ -46,6 +46,7 @@ CWII_IPC_HLE_Device_usb_oh1_57e_305_emu::CWII_IPC_HLE_Device_usb_oh1_57e_305_emu
   else
   {
     sysconf = SConfig::GetInstance().m_SYSCONF;
+    BackUpBTInfoSection();
   }
 
   // Activate only first Wiimote by default
@@ -62,24 +63,13 @@ CWII_IPC_HLE_Device_usb_oh1_57e_305_emu::CWII_IPC_HLE_Device_usb_oh1_57e_305_emu
     u8 i = 0;
     while (i < MAX_BBMOTES)
     {
-      if (i < BT_DINF.num_registered)
-      {
-        tmpBD.b[5] = BT_DINF.active[i].bdaddr[0] = BT_DINF.registered[i].bdaddr[0];
-        tmpBD.b[4] = BT_DINF.active[i].bdaddr[1] = BT_DINF.registered[i].bdaddr[1];
-        tmpBD.b[3] = BT_DINF.active[i].bdaddr[2] = BT_DINF.registered[i].bdaddr[2];
-        tmpBD.b[2] = BT_DINF.active[i].bdaddr[3] = BT_DINF.registered[i].bdaddr[3];
-        tmpBD.b[1] = BT_DINF.active[i].bdaddr[4] = BT_DINF.registered[i].bdaddr[4];
-        tmpBD.b[0] = BT_DINF.active[i].bdaddr[5] = BT_DINF.registered[i].bdaddr[5];
-      }
-      else
-      {
+      // Previous records can be safely overwritten, since they are backed up
       tmpBD.b[5] = BT_DINF.active[i].bdaddr[0] = BT_DINF.registered[i].bdaddr[0] = i;
       tmpBD.b[4] = BT_DINF.active[i].bdaddr[1] = BT_DINF.registered[i].bdaddr[1] = 0;
       tmpBD.b[3] = BT_DINF.active[i].bdaddr[2] = BT_DINF.registered[i].bdaddr[2] = 0x79;
       tmpBD.b[2] = BT_DINF.active[i].bdaddr[3] = BT_DINF.registered[i].bdaddr[3] = 0x19;
       tmpBD.b[1] = BT_DINF.active[i].bdaddr[4] = BT_DINF.registered[i].bdaddr[4] = 2;
       tmpBD.b[0] = BT_DINF.active[i].bdaddr[5] = BT_DINF.registered[i].bdaddr[5] = 0x11;
-      }
 
       const char* wmName;
       if (i == WIIMOTE_BALANCE_BOARD)
@@ -95,6 +85,7 @@ CWII_IPC_HLE_Device_usb_oh1_57e_305_emu::CWII_IPC_HLE_Device_usb_oh1_57e_305_emu
       i++;
     }
 
+    BT_DINF.num_registered = MAX_BBMOTES;
     // save now so that when games load sysconf file it includes the new Wiimotes
     // and the correct order for connected Wiimotes
     if (!sysconf->SetArrayData("BT.DINF", (u8*)&BT_DINF, sizeof(_conf_pads)) || !sysconf->Save())