From 5ec08cb84abbceace3d3382000f48a8d2d7ca30e Mon Sep 17 00:00:00 2001
From: belliash <belliash@codingworkshop.eu.org>
Date: Wed, 16 Nov 2022 15:03:33 +0100
Subject: [PATCH] Implement PeGetSubSystem() routine

---
 xtldr/includes/blmod.h                 |  2 ++
 xtldr/modules/pecoff/includes/pecoff.h |  4 ++++
 xtldr/modules/pecoff/pecoff.c          | 22 ++++++++++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/xtldr/includes/blmod.h b/xtldr/includes/blmod.h
index 66f415a..cc45a30 100644
--- a/xtldr/includes/blmod.h
+++ b/xtldr/includes/blmod.h
@@ -22,6 +22,7 @@ typedef struct _XT_PECOFFF_IMAGE_PROTOCOL XT_PECOFF_IMAGE_PROTOCOL, *PXT_PECOFF_
 /* Pointers to the routines provided by the modules */
 typedef EFI_STATUS (*PXT_BOOTPROTO_BOOT_SYSTEM)(IN PXT_BOOT_PROTOCOL_PARAMETERS Parameters);
 typedef EFI_STATUS (*PXT_PECOFF_GET_ENTRY_POINT)(IN PPECOFF_IMAGE_CONTEXT Image, OUT PVOID *EntryPoint);
+typedef EFI_STATUS (*PXT_PECOFF_GET_SUBSYSTEM)(IN PPECOFF_IMAGE_CONTEXT Image, OUT PUSHORT SubSystem);
 typedef EFI_STATUS (*PXT_PECOFF_LOAD_IMAGE)(IN PEFI_FILE_HANDLE FileHandle, IN LOADER_MEMORY_TYPE MemoryType,
                                             IN PVOID VirtualAddress, OUT PPECOFF_IMAGE_CONTEXT *Image);
 typedef EFI_STATUS (*PXT_PECOFF_RELOCATE_IMAGE)(IN PPECOFF_IMAGE_CONTEXT Image, IN EFI_VIRTUAL_ADDRESS Address);
@@ -49,6 +50,7 @@ typedef struct _XT_BOOT_PROTOCOL_PARAMETERS
 typedef struct _XT_PECOFFF_IMAGE_PROTOCOL
 {
     PXT_PECOFF_GET_ENTRY_POINT GetEntryPoint;
+    PXT_PECOFF_GET_SUBSYSTEM GetSubSystem;
     PXT_PECOFF_LOAD_IMAGE Load;
     PXT_PECOFF_RELOCATE_IMAGE Relocate;
 } XT_PECOFF_IMAGE_PROTOCOL, *PXT_PECOFF_IMAGE_PROTOCOL;
diff --git a/xtldr/modules/pecoff/includes/pecoff.h b/xtldr/modules/pecoff/includes/pecoff.h
index 885f885..1c61de1 100644
--- a/xtldr/modules/pecoff/includes/pecoff.h
+++ b/xtldr/modules/pecoff/includes/pecoff.h
@@ -17,6 +17,10 @@ EFI_STATUS
 PeGetEntryPoint(IN PPECOFF_IMAGE_CONTEXT Image,
                 OUT PVOID *EntryPoint);
 
+EFI_STATUS
+PeGetSubSystem(IN PPECOFF_IMAGE_CONTEXT Image,
+               OUT PUSHORT SubSystem);
+
 EFI_STATUS
 PeLoadImage(IN PEFI_FILE_HANDLE FileHandle,
             IN LOADER_MEMORY_TYPE MemoryType,
diff --git a/xtldr/modules/pecoff/pecoff.c b/xtldr/modules/pecoff/pecoff.c
index a815232..3992223 100644
--- a/xtldr/modules/pecoff/pecoff.c
+++ b/xtldr/modules/pecoff/pecoff.c
@@ -50,6 +50,27 @@ PeGetEntryPoint(IN PPECOFF_IMAGE_CONTEXT Image,
     return STATUS_EFI_SUCCESS;
 }
 
+/**
+ * Returns an information about subsystem that is required to run PE/COFF image.
+ *
+ * @param Image
+ *        A pointer to the PE/COFF context structure representing the loaded image.
+ *
+ * @param SubSystem
+ *        A pointer to the memory area storing a value defined for the 'subsystem' field of the image.
+ *
+ * @return This routine returns a status code.
+ *
+ * @since XT 1.0
+ */
+EFI_STATUS
+PeGetSubSystem(IN PPECOFF_IMAGE_CONTEXT Image,
+               OUT PUSHORT SubSystem)
+{
+    *SubSystem = Image->PeHeader->OptionalHeader.Subsystem;
+    return STATUS_EFI_SUCCESS;
+}
+
 /**
  * Loads a PE/COFF image file.
  *
@@ -526,6 +547,7 @@ BlXtLdrModuleMain(IN EFI_HANDLE ImageHandle,
 
     /* Set routines available via PE/COFF image protocol */
     XtPeCoffProtocol.GetEntryPoint = PeGetEntryPoint;
+    XtPeCoffProtocol.GetSubSystem = PeGetSubSystem;
     XtPeCoffProtocol.Load = PeLoadImage;
     XtPeCoffProtocol.Relocate = PeRelocateImage;