/** @file
  This is DCS boot loader application

Copyright (c) 2016. Disk Cryptography Services for EFI (DCS), Alex Kolotnikov
Copyright (c) 2016. VeraCrypt, Mounir IDRASSI 

This program and the accompanying materials
are licensed and made available under the terms and conditions
of the GNU Lesser General Public License, version 3.0 (LGPL-3.0).

The full text of the license may be found at
https://opensource.org/licenses/LGPL-3.0
**/

#include <Uefi.h>
#include <Library/CommonLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/DevicePathLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/PrintLib.h>
#include <Protocol/DcsBmlProto.h>
#include "DcsConfig.h"
#include <Guid/Gpt.h>
#include <Guid/GlobalVariable.h>

EFI_GUID          ImagePartGuid;
EFI_GUID          *gEfiExecPartGuid = &ImagePartGuid;
CHAR16            *gEfiExecCmdDefault = L"\\EFI\\Microsoft\\Boot\\Bootmgfw_ms.vc";
CHAR16            *gEfiExecCmdMS = L"\\EFI\\Microsoft\\Boot\\Bootmgfw.efi";
CHAR16            *gEfiExecCmd = NULL;
CHAR8             gDoExecCmdMsg[256];
CONST CHAR8* 	  g_szMsBootString = "bootmgfw.pdb";

EFI_STATUS
DoExecCmd() 
{
	EFI_STATUS          res;
	gDoExecCmdMsg[0] = 0;
	res = EfiFindPartByGUID(gEfiExecPartGuid, &gFileRootHandle);
	if (!EFI_ERROR(res)) {
		res = FileOpenRoot(gFileRootHandle, &gFileRoot);
		if (!EFI_ERROR(res)) {
            UINT32 lockFlags = 0;
            // Lock EFI boot variables
            InitBml();
            lockFlags = ConfigReadInt("DcsBmlLockFlags", BML_LOCK_SETVARIABLE | BML_SET_BOOTNEXT | BML_UPDATE_BOOTORDER);
            BmlLock(lockFlags);
			res = EfiExec(NULL, gEfiExecCmd);
			if (EFI_ERROR(res))
				AsciiSPrint(gDoExecCmdMsg, sizeof(gDoExecCmdMsg), "\nCan't exec %s start partition %g\n", gEfiExecCmd, gEfiExecPartGuid);
			else
				AsciiSPrint(gDoExecCmdMsg, sizeof(gDoExecCmdMsg), "\nDone exec %s start partition %g\n", gEfiExecCmd, gEfiExecPartGuid);
		}	else {
			AsciiSPrint(gDoExecCmdMsg, sizeof(gDoExecCmdMsg), "\nCan't open start partition %g\n", gEfiExecPartGuid);
		}
	}	else {
		AsciiSPrint(gDoExecCmdMsg, sizeof(gDoExecCmdMsg), "\nCan't find start partition %g\n", gEfiExecPartGuid);
	}
	return res;
}

EFI_STATUS
ExecMSWindowsLoader() {
	
	if (!EFI_ERROR(FileExist(NULL, gEfiExecCmdDefault)))
		return EfiExec(NULL, gEfiExecCmdDefault);
	else
	{
		if (!EFI_ERROR(FileExist(NULL, gEfiExecCmdMS)))
		{
			/* check if it is Microsoft one */
			UINT8*      fileData = NULL;
			UINTN       fileSize = 0;
			BOOLEAN		bFound = FALSE;
			if (!EFI_ERROR(FileLoad(NULL, gEfiExecCmdMS, &fileData, &fileSize)))
			{
				if ((fileSize > 32768) && !EFI_ERROR(MemoryHasPattern(fileData, fileSize, g_szMsBootString, AsciiStrLen(g_szMsBootString))))
				{
					bFound = TRUE;
				}
			}
			
			MEM_FREE(fileData);
			
			if (bFound)
				return EfiExec(NULL, gEfiExecCmdMS);
		}

		ERR_PRINT(L"Could not find the original Windows loader\r\n");
		
		return EFI_NOT_READY;
	}
}

//////////////////////////////////////////////////////////////////////////
// BML
//////////////////////////////////////////////////////////////////////////
CHAR16* sDcsBmlEfi = L"EFI\\VeraCrypt\\DcsBml.dcs";
CHAR16* sDcsBmlEfiDesc = L"VeraCrypt(DcsBml) driver";
CHAR16* sDcsBmlDriverVar = L"DriverDC5B";
UINT16  DcsBmlDriverNum = 0x0DC5B;

VOID
UpdateDriverBmlStart() {
    EFI_STATUS          res;
    UINTN               len;
    UINT32              attr;
    int                 drvInst;
    CHAR16*             tmp = NULL;

    // Driver load selected?
    drvInst = ConfigReadInt("DcsBmlDriver", 0);
    if (drvInst) {
        res = EfiGetVar(sDcsBmlDriverVar, &gEfiGlobalVariableGuid, &tmp, &len, &attr);
        // Driver installed?
        if (EFI_ERROR(res)) {
            // No -> install
            res = BootMenuItemCreate(sDcsBmlDriverVar, sDcsBmlEfiDesc, gFileRootHandle, sDcsBmlEfi, FALSE);
//            ERR_PRINT(L"Drv %s %r\n", sDcsBmlDriverVar, res);
            if (!EFI_ERROR(res)) {
                len = 0;
                res = EfiGetVar(L"DriverOrder", &gEfiGlobalVariableGuid, &tmp, &len, &attr);
                if (!EFI_ERROR(res)) len = len / 2;
                res = BootOrderInsert(L"DriverOrder", len, DcsBmlDriverNum);
            }
//            ERR_PRINT(L"Drv order %d %r\n", len, res);
        }
        MEM_FREE(tmp);
    }
    else {
        // uninstall driver
        res = EfiGetVar(sDcsBmlDriverVar, &gEfiGlobalVariableGuid, &tmp, &len, &attr);
        if (!EFI_ERROR(res)) {
            BootMenuItemRemove(sDcsBmlDriverVar);
            BootOrderRemove(L"DriverOrder", DcsBmlDriverNum);
        }
    }
    MEM_FREE(tmp);
}

/**
The actual entry point for the application.

@param[in] ImageHandle    The firmware allocated handle for the EFI image.
@param[in] SystemTable    A pointer to the EFI System Table.

@retval EFI_SUCCESS       The entry point executed successfully.
@retval other             Some error occur when executing this entry point.

**/
EFI_STATUS
EFIAPI
DcsBootMain(
   IN EFI_HANDLE        ImageHandle,
   IN EFI_SYSTEM_TABLE  *SystemTable
   )
{
   EFI_STATUS           res;
	UINTN               len;
	UINT32              attr;
	BOOLEAN             searchOnESP = FALSE;
	BOOLEAN             searchMsOnESP = FALSE;
	EFI_GUID          *pEfiExecPartBackup = NULL;
//	EFI_INPUT_KEY       key;

	InitBio();
   res = InitFS();
   if (EFI_ERROR(res)) {
      ERR_PRINT(L"InitFS %r\n", res);
   }

   // BML installed?
   if (EFI_ERROR(InitBml())) {
       // if not -> execute
       EfiExec(NULL, sDcsBmlEfi);
   }

   UpdateDriverBmlStart();

	// Try platform info
	if (EFI_ERROR(FileExist(NULL, L"\\EFI\\VeraCrypt\\PlatformInfo")) &&
		!EFI_ERROR(FileExist(NULL, L"\\EFI\\VeraCrypt\\DcsInfo.dcs"))) {
		res = EfiExec(NULL, L"\\EFI\\VeraCrypt\\DcsInfo.dcs");
		if (!EFI_ERROR(res) && 
			!EFI_ERROR(FileExist(NULL, L"\\EFI\\VeraCrypt\\PlatformInfo"))) {
			gST->RuntimeServices->ResetSystem(EfiResetCold, EFI_SUCCESS, 0, NULL);
		}
	}

	// Load all drivers
	res = EfiExec(NULL, L"\\EFI\\VeraCrypt\\LegacySpeaker.dcs");

	res = EfiGetPartGUID(gFileRootHandle, &ImagePartGuid);
	if (EFI_ERROR(res)) {
		ERR_PRINT(L"\nStart partition %r\n", res);
		return res;
	}

	EfiSetVar(L"DcsExecPartGuid", NULL, &ImagePartGuid, sizeof(EFI_GUID), EFI_VARIABLE_BOOTSERVICE_ACCESS);
	EfiSetVar(L"DcsExecCmd", NULL, gEfiExecCmdDefault, (StrLen(gEfiExecCmdDefault) + 1) * 2, EFI_VARIABLE_BOOTSERVICE_ACCESS);
	// Authorize
	gBS->SetWatchdogTimer(0, 0, 0, NULL);
	res = EfiExec(NULL, L"\\EFI\\VeraCrypt\\DcsInt.dcs");
   if (EFI_ERROR(res) && (res != EFI_DCS_POSTEXEC_REQUESTED)) {

      // Clear DcsExecPartGuid before execute OS to avoid problem in VirtualBox with reboot.
      EfiSetVar(L"DcsExecPartGuid", NULL, NULL, 0, EFI_VARIABLE_BOOTSERVICE_ACCESS);
      EfiSetVar(L"DcsExecCmd", NULL, NULL, 0, EFI_VARIABLE_BOOTSERVICE_ACCESS);
      // ERR_PRINT(L"\nDcsInt.efi %r\n",res);
	  if (res == EFI_DCS_SHUTDOWN_REQUESTED)
	  {
		res = EFI_SUCCESS;
		gST->RuntimeServices->ResetSystem(EfiResetShutdown, EFI_SUCCESS, 0, NULL);
	  }
	  else if (res == EFI_DCS_REBOOT_REQUESTED)
	  {
		res = EFI_SUCCESS;
		gST->RuntimeServices->ResetSystem(EfiResetCold, EFI_SUCCESS, 0, NULL);
	  }
	  else if (res == EFI_DCS_HALT_REQUESTED)
	  {
		  EfiCpuHalt();
	  }
	  else if (res == EFI_DCS_USER_CANCELED)
	  {
		  /* If user cancels password prompt, call original Windows loader */
		  res = ExecMSWindowsLoader ();
	  }
      return res;
   }

	res = EfiGetVar(L"DcsExecPartGuid", NULL, &gEfiExecPartGuid, &len, &attr);
	if (EFI_ERROR(res)) {
		gEfiExecPartGuid = &ImagePartGuid;
	}
	
	pEfiExecPartBackup = gEfiExecPartGuid;

	res = EfiGetVar(L"DcsExecCmd", NULL, &gEfiExecCmd, &len, &attr);
	if (EFI_ERROR(res)) {
		gEfiExecCmd = gEfiExecCmdDefault;
	}

	searchOnESP = CompareGuid(gEfiExecPartGuid, &ImagePartGuid) &&
		EFI_ERROR(FileExist(NULL, gEfiExecCmd));
		
	searchMsOnESP = CompareGuid(gEfiExecPartGuid, &ImagePartGuid) &&
		EFI_ERROR(FileExist(NULL, gEfiExecCmdMS));

    // Clear DcsExecPartGuid before execute OS to avoid problem in VirtualBox with reboot.
    EfiSetVar(L"DcsExecPartGuid", NULL, NULL, 0, EFI_VARIABLE_BOOTSERVICE_ACCESS);
    EfiSetVar(L"DcsExecCmd", NULL, NULL, 0, EFI_VARIABLE_BOOTSERVICE_ACCESS);

	// Find new start partition
    ConnectAllEfi();
	InitBio();
	res = InitFS();

	while (1)
	{
		// Default load of bootmgfw?
		if (searchOnESP) {
			// gEfiExecCmd is not found on start partition. Try from ESP
			EFI_BLOCK_IO_PROTOCOL *bio = NULL;
			EFI_PARTITION_TABLE_HEADER *gptHdr = NULL;
			EFI_PARTITION_ENTRY        *gptEntry = NULL;
			HARDDRIVE_DEVICE_PATH hdp;
			EFI_HANDLE disk;
			if (!EFI_ERROR(res = EfiGetPartDetails(gFileRootHandle, &hdp, &disk))) {
				if ((bio = EfiGetBlockIO(disk)) != NULL) {
					if (!EFI_ERROR(res = GptReadHeader(bio, 1, &gptHdr)) &&
						!EFI_ERROR(res = GptReadEntryArray(bio, gptHdr, &gptEntry))) {
						UINT32 i;
						for (i = 0; i < gptHdr->NumberOfPartitionEntries; ++i) {
							if (CompareGuid(&gptEntry[i].PartitionTypeGUID, &gEfiPartTypeSystemPartGuid)) {
								// select ESP GUID
								CopyGuid(gEfiExecPartGuid, &gptEntry[i].UniquePartitionGUID);
								res = DoExecCmd();
								if(EFI_ERROR(res)) continue;
							}
						}
					}
				}
			}
		}	else {
			res = DoExecCmd();
		}
		
		if(EFI_ERROR(res))
		{
			if (0 == StrCmp (gEfiExecCmd, gEfiExecCmdDefault))
			{
				gEfiExecCmd = gEfiExecCmdMS;
				searchOnESP = searchMsOnESP;
				gEfiExecPartGuid = pEfiExecPartBackup;
			}
			else
				break;
		}
		else
			break;
	}
	ERR_PRINT(L"%a\nStatus -  %r", gDoExecCmdMsg, res);
	EfiCpuHalt();
   return EFI_INVALID_PARAMETER;
}