2 files changed, 123 insertions, 0 deletions
diff --git a/Lesson_21/UefiLessonsPkg/ImageHandle/ImageHandle.c b/Lesson_21/UefiLessonsPkg/ImageHandle/ImageHandle.c
new file mode 100644
index 0000000..32e9c43
--- /dev/null
+++ b/Lesson_21/UefiLessonsPkg/ImageHandle/ImageHandle.c
@@ -0,0 +1,105 @@
+#include <Library/MemoryAllocationLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+typedef struct {
+  UINTN               Signature;
+  /// All handles list of IHANDLE
+  LIST_ENTRY          AllHandles;
+  /// List of PROTOCOL_INTERFACE's for this handle
+  LIST_ENTRY          Protocols;
+  UINTN               LocateRequest;
+  /// The Handle Database Key value when this handle was last created or modified
+  UINT64              Key;
+} IHANDLE;
+
+typedef struct {
+  UINTN               Signature;
+  /// Link Entry inserted to mProtocolDatabase
+  LIST_ENTRY          AllEntries;
+  /// ID of the protocol
+  EFI_GUID            ProtocolID;
+  /// All protocol interfaces
+  LIST_ENTRY          Protocols;
+  /// Registerd notification handlers
+  LIST_ENTRY          Notify;
+} PROTOCOL_ENTRY;
+
+typedef struct {
+  UINTN                       Signature;
+  /// Link on IHANDLE.Protocols
+  LIST_ENTRY                  Link;
+  /// Back pointer
+  IHANDLE                     *Handle;
+  /// Link on PROTOCOL_ENTRY.Protocols
+  LIST_ENTRY                  ByProtocol;
+  /// The protocol ID
+  PROTOCOL_ENTRY              *Protocol;
+  /// The interface value
+  VOID                        *Interface;
+  /// OPEN_PROTOCOL_DATA list
+  LIST_ENTRY                  OpenList;
+  UINTN                       OpenListCount;
+
+} PROTOCOL_INTERFACE;
+
+
+#define offsetof(a,b) ((INTN)(&(((a*)(0))->b)))
+
+#define container_of(ptr, type, member) ({                      \
+        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
+        (type *)( (char *)__mptr - offsetof(type,member) );})
+
+EFI_STATUS
+EFIAPI
+UefiMain (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  IHANDLE* MyHandle = ImageHandle;
+  Print(L"Signature: %c %c %c %c\n", (MyHandle->Signature >>  0) & 0xff,
+                                     (MyHandle->Signature >>  8) & 0xff,
+                                     (MyHandle->Signature >> 16) & 0xff,
+                                     (MyHandle->Signature >> 24) & 0xff);
+
+  Print(L"Back Protocol Interface Link: %p\n", MyHandle->Protocols.BackLink);
+  Print(L"Forward Protocol Interface Link: %p\n", MyHandle->Protocols.ForwardLink);
+
+  LIST_ENTRY *FirstLink = MyHandle->Protocols.ForwardLink;
+  LIST_ENTRY *CurrentLink = FirstLink;
+  do {
+  	PROTOCOL_INTERFACE* MyProtocolInterface = container_of(CurrentLink, PROTOCOL_INTERFACE, Link);
+
+        Print(L"\n");
+        Print(L"Current Link: %p\n", CurrentLink);
+  	Print(L"Signature: %x %x %x %x\n", (MyProtocolInterface->Signature >>  0) & 0xff,
+        	                           (MyProtocolInterface->Signature >>  8) & 0xff,
+                	                   (MyProtocolInterface->Signature >> 16) & 0xff,
+                        	           (MyProtocolInterface->Signature >> 24) & 0xff);
+
+  	Print(L"Back Link: %p\n", MyProtocolInterface->Link.BackLink);
+	Print(L"Forward Link: %p\n", MyProtocolInterface->Link.ForwardLink);
+	Print(L"GUID=%g\n", MyProtocolInterface->Protocol->ProtocolID);
+        CurrentLink = MyProtocolInterface->Link.ForwardLink;
+  } while (CurrentLink != FirstLink);
+
+  Print(L"________\n");
+  EFI_GUID **ProtocolGuidArray;
+  UINTN ArrayCount;
+  //EFI_STATUS Status = gBS->ProtocolsPerHandle(NULL,		// Use this to test %r Print formatting option
+  EFI_STATUS Status = gBS->ProtocolsPerHandle(ImageHandle,
+					      &ProtocolGuidArray,
+					      &ArrayCount);
+
+  if (!EFI_ERROR(Status)) {
+    for (int i=0; i<ArrayCount; i++) {
+      Print(L"%g\n", ProtocolGuidArray[i]);
+    }
+    FreePool(ProtocolGuidArray);
+  } else {
+    Print(L"ProtocolsPerHandle error: %r\n", Status);
+  }
+
+  return EFI_SUCCESS;
+}
diff --git a/Lesson_21/UefiLessonsPkg/ImageHandle/ImageHandle.inf b/Lesson_21/UefiLessonsPkg/ImageHandle/ImageHandle.inf
new file mode 100644
index 0000000..34256ee
--- /dev/null
+++ b/Lesson_21/UefiLessonsPkg/ImageHandle/ImageHandle.inf
@@ -0,0 +1,18 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = ImageHandle
+  FILE_GUID                      = b68d3472-70c7-4928-841b-6566032e0a23
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = UefiMain
+
+[Sources]
+  ImageHandle.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+