From 5135d1a3579104b4c69994135c424c5a524c11f9 Mon Sep 17 00:00:00 2001
From: Mounir IDRASSI <mounir.idrassi@idrix.fr>
Date: Mon, 23 Sep 2019 15:38:14 +0200
Subject: Ensure that the correct Windows bootloader is executed when the user
 press ESCAPE

---
 DcsBoot/DcsBoot.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/DcsBoot/DcsBoot.c b/DcsBoot/DcsBoot.c
index 18fb005..080b052 100644
--- a/DcsBoot/DcsBoot.c
+++ b/DcsBoot/DcsBoot.c
@@ -29,6 +29,7 @@ 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() 
@@ -58,6 +59,39 @@ DoExecCmd()
 	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
 //////////////////////////////////////////////////////////////////////////
@@ -186,7 +220,7 @@ DcsBootMain(
 	  else if (res == EFI_DCS_USER_CANCELED)
 	  {
 		  /* If user cancels password prompt, call original Windows loader */
-		  res = EfiExec(NULL, gEfiExecCmdDefault);
+		  res = ExecMSWindowsLoader ();
 	  }
       return res;
    }
-- 
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