Add lesson 15

Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>

20 files changed, 1138 insertions, 0 deletions

diff --git a/Lesson_15/Conf/target.txt b/Lesson_15/Conf/target.txt
new file mode 100644
index 0000000..c109dcf
--- /dev/null
+++ b/Lesson_15/Conf/target.txt
@@ -0,0 +1,7 @@
+ACTIVE_PLATFORM       = UefiLessonsPkg/UefiLessonsPkg.dsc

+TARGET                = RELEASE

+TARGET_ARCH           = X64

+TOOL_CHAIN_CONF       = Conf/tools_def.txt

+TOOL_CHAIN_TAG        = GCC5

+BUILD_RULE_CONF = Conf/build_rule.txt

+

diff --git a/Lesson_15/README.md b/Lesson_15/README.md
new file mode 100644
index 0000000..2f72644
--- /dev/null
+++ b/Lesson_15/README.md
@@ -0,0 +1,400 @@
+Let's print content of variables that define boot options in UEFI.
+
+To do it, we need to use `GetVariable()` API function from the EFI Runtime Services:
+```
+GetVariable()
+
+Summary:
+Returns the value of a variable.
+
+Prototype:
+typedef
+EFI_STATUS
+GetVariable (
+ IN CHAR16 *VariableName,
+ IN EFI_GUID *VendorGuid,
+ OUT UINT32 *Attributes OPTIONAL,
+ IN OUT UINTN *DataSize,
+ OUT VOID *Data OPTIONAL
+ );
+
+Parameters:
+VariableName    A Null-terminated string that is the name of the vendor’s variable.
+VendorGuid      A unique identifier for the vendor
+Attributes      If not NULL, a pointer to the memory location to return the
+                attributes bitmask for the variable.
+                If not NULL, then Attributes is set on output both when
+                EFI_SUCCESS and when EFI_BUFFER_TOO_SMALL is returned.
+DataSize        On input, the size in bytes of the return Data buffer.
+                On output the size of data returned in Data.
+Data            The buffer to return the contents of the variable. May be NULL
+                with a zero DataSize in order to determine the size buffer needed.
+
+Description:
+Each vendor may create and manage its own variables without the risk of name conflicts by using a
+unique VendorGuid. When a variable is set its Attributes are supplied to indicate how the data variable
+should be stored and maintained by the system. The attributes affect when the variable may be accessed
+and volatility of the data
+
+If the Data buffer is too small to hold the contents of the variable, the error EFI_BUFFER_TOO_SMALL is
+returned and DataSize is set to the required buffer size to obtain the data.
+
+Status Codes Returned:
+EFI_SUCCESS 		The function completed successfully.
+EFI_NOT_FOUND 		The variable was not found.
+EFI_BUFFER_TOO_SMALL 	The DataSize is too small for the result. DataSize has been
+			updated with the size needed to complete the request. If
+			Attributes is not NULL, then the attributes bitmask for the
+			variable has been stored to the memory location pointed-to by
+			Attributes.
+...
+
+```
+
+In previous lesson we've discovered that these options are present in our environment under GUID `EFI_GLOBAL_VARIABLE` (gEfiGlobalVariableGuid):
+```
+Boot0000
+Boot0001
+Boot0002
+Boot0003
+Boot0004
+BootCurrent
+BootOrder
+```
+
+If we look at the UEFI spec for these options description we would find:
+```
+Each Boot#### variable contains an EFI_LOAD_OPTION. Each Boot#### variable is the name “Boot”
+appended with a unique four digit hexadecimal number. For example, Boot0001, Boot0002, Boot0A02,
+etc.
+
+...
+
+The BootOrder variable contains an array of UINT16’s that make up an ordered list of the Boot####
+options. The first element in the array is the value for the first logical boot option, the second element is
+the value for the second logical boot option, etc. The BootOrder order list is used by the firmware’s
+boot manager as the default boot order.
+
+...
+
+The BootCurrent variable is a single UINT16 that defines the Boot#### option that was selected on
+the current boot.
+```
+
+Create `ShowBootVariables` for this lesson.
+
+First let's try to get simple `UINT16 BootCurrent` option.
+
+We would be getting variables a lot in this program, so it is best to create a function that abstracts all the necessities of the `GetVariable` API calls:
+```
+EFI_STATUS
+GetNvramVariable( CHAR16   *VariableName,
+                  EFI_GUID *VariableOwnerGuid,
+                  VOID     **Buffer,
+                  UINTN    *BufferSize)
+{
+    UINTN Size = 0;
+    *BufferSize = 0;
+
+    EFI_STATUS Status = gRT->GetVariable(VariableName, VariableOwnerGuid, NULL, &Size, NULL);
+    if (Status != EFI_BUFFER_TOO_SMALL) {
+        Print(L"Error! 'gRT->GetVariable' call returned %r\n", Status);
+        return Status;
+    }
+
+    *Buffer = AllocateZeroPool(Size);
+    if (!Buffer) {
+        Print(L"Error! 'AllocateZeroPool' call returned %r\n", Status);
+        return EFI_OUT_OF_RESOURCES;
+    }
+
+    Status = gRT->GetVariable(VariableName, VariableOwnerGuid, NULL, &Size, *Buffer);
+    if (Status == EFI_SUCCESS) {
+        *BufferSize = Size;
+    } else {
+        FreePool( *Buffer );
+        *Buffer = NULL;
+    }
+
+    return Status;
+}
+```
+
+As with many other different UEFI APIs first `GetVariable` call gives us `EFI_BUFFER_TOO_SMALL` error, but fills `Size` variable with the size of the array that we need to allocate and pass to this function for the correct execution.
+We allocate necessary size with the `AllocateZeroPool` edk2 library call, like we did it in previous lesson. After that we call `GetVariable` function for the second time, expecting `EFI_SUCCESS` status.
+
+
+The main function would look like this:
+```
+#include <Library/UefiRuntimeServicesTableLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+#include <Library/MemoryAllocationLib.h>
+
+EFI_STATUS
+GetNvramVariable( CHAR16   *VariableName,
+                  EFI_GUID *VariableOwnerGuid,
+                  VOID     **Buffer,
+                  UINTN    *BufferSize)
+{
+  ...
+}
+
+INTN EFIAPI ShellAppMain(IN UINTN Argc, IN CHAR16 **Argv)
+{
+  UINTN OptionSize;
+  EFI_STATUS Status;
+
+  UINT16* BootCurrent;
+  Status = GetNvramVariable(L"BootCurrent", &gEfiGlobalVariableGuid, (VOID**)&BootCurrent, &OptionSize);
+  if (Status == EFI_SUCCESS) {
+    Print(L"BootCurrent=%d\n", *BootCurrent);
+  } else {
+    Print(L"Can't get BootCurrent variable\n");
+  }
+
+  return EFI_SUCCESS;
+}
+```
+
+If we execute this code under OVMF we would get:
+```
+FS0:\> ShowBootVariables.efi
+3
+```
+This means that `Boot0003` is active.
+
+
+Now let's get `UINT16 BootOrder[]` variable. It is an array of XXXX numbers that describe Boot option priority.
+So `{0,2,4,1,3}` for example would mean this order:
+```
+Boot0000
+Boot0002
+Boot0004
+Boot0001
+Boot0003
+```
+
+This is the code to get and print this array:
+```
+UINT16* BootOrderArray;
+Status = GetNvramVariable(L"BootOrder", &gEfiGlobalVariableGuid, (VOID**)&BootOrderArray, &OptionSize);
+if (Status == EFI_SUCCESS) {
+  for (UINTN i=0; i<(OptionSize/sizeof(UINT16)); i++) {
+    Print(L"Boot%04d%s\n", BootOrderArray[i], (BootOrderArray[i] == *BootCurrent)? L"*" : L"" );
+  }
+} else {
+  Print(L"Can't get BootOrder variable\n");
+}
+```
+
+If we execute this code under OVMF we would get:
+```
+Boot0000
+Boot0001
+Boot0002
+Boot0003*
+Boot0004
+```
+
+
+Now let's print information about every `Boot####` option.
+
+According to the UEFI the spec these options are stored in a `EFI_LOAD_OPTION` structure:
+```
+typedef struct _EFI_LOAD_OPTION {
+ UINT32 Attributes;
+ UINT16 FilePathListLength;
+ // CHAR16 Description[];
+ // EFI_DEVICE_PATH_PROTOCOL FilePathList[];
+ // UINT8 OptionalData[];
+} EFI_LOAD_OPTION;
+
+Parameters
+Attributes 		The attributes for this load option entry. All unused bits must be zero
+			and are reserved by the UEFI specification for future growth.
+FilePathListLength	Length in bytes of the FilePathList. OptionalData starts at
+			offset sizeof(UINT32) + sizeof(UINT16) +
+			StrSize(Description) + FilePathListLength of the
+			EFI_LOAD_OPTION descriptor.
+Description 		The user readable description for the load option. This field ends
+			with a Null character.
+FilePathList 		A packed array of UEFI device paths. The first element of the array is
+			a device path that describes the device and location of the Image for
+			this load option. The FilePathList[0] is specific to the device
+			type. Other device paths may optionally exist in the FilePathList,
+			but their usage is OSV specific. Each element in the array is variable
+			length, and ends at the device path end structure. Because the size
+			of Description is arbitrary, this data structure is not guaranteed
+			to be aligned on a natural boundary. This data structure may have to
+			be copied to an aligned natural boundary before it is used.
+OptionalData 		The remaining bytes in the load option descriptor are a binary data
+			buffer that is passed to the loaded image. If the field is zero bytes
+			long, a NULL pointer is passed to the loaded image. The number of
+			bytes in OptionalData can be computed by subtracting the
+			starting offset of OptionalData from total size in bytes of the
+			EFI_LOAD_OPTION. 
+```
+
+Pay attention to the fact that some fields in this structure are commented:
+```
+// CHAR16 Description[];
+// EFI_DEVICE_PATH_PROTOCOL FilePathList[];
+// UINT8 OptionalData[];
+```
+It is because these fields are variable size arrays, so we need to calculate offsets to them dynamically.
+
+Create a function that accepts names of a Boot variable (such as "Boot0003") and outputs all the needed information about it:
+```
+VOID PrintBootOption(CHAR16* BootOptionName)
+{
+  UINTN OptionSize;
+  UINT8* Buffer;
+
+  EFI_STATUS Status = GetNvramVariable(BootOptionName, &gEfiGlobalVariableGuid, (VOID**)&Buffer, &OptionSize);
+  if (Status == EFI_SUCCESS) {
+      EFI_LOAD_OPTION* LoadOption = (EFI_LOAD_OPTION*) Buffer;
+      CHAR16* Description = (CHAR16*)(Buffer + sizeof (EFI_LOAD_OPTION));
+      UINTN DescriptionSize = StrSize(Description);
+
+      Print(L"%s\n", Description);
+      if (LoadOption->FilePathListLength != 0) {
+        VOID* FilePathList = (UINT8 *)Description + DescriptionSize;
+        CHAR16* DevPathString = ConvertDevicePathToText(FilePathList, TRUE, FALSE);
+        Print(L"%s\n", DevPathString);
+      }
+  } else {
+    Print(L"Can't get %s variable\n", BootOptionName);
+  }
+}
+```
+
+This code uses pointer arithmetics that we've discussed above. To get `Description` field size we simply use `StrSize(Description)` call as `Description` field always ends with Null.
+
+To print DevicePath as a string we use `ConvertDevicePathToText` call (we've used it earlier in our `ImageInfo` application). To use it we need to add `#include <Library/DevicePathLib.h>` to our program.
+
+Now we need to construct "BootXXXX" variables from a `BootOrder` numbers.
+
+To do so we would use `UnicodeSPrint` function from the https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Library/PrintLib.h
+```
+/**
+  Produces a Null-terminated Unicode string in an output buffer based on a Null-terminated
+  Unicode format string and variable argument list.
+  This function is similar as snprintf_s defined in C11.
+
+  ...
+
+  @param  StartOfBuffer   A pointer to the output buffer for the produced Null-terminated
+                          Unicode string.
+  @param  BufferSize      The size, in bytes, of the output buffer specified by StartOfBuffer.
+  @param  FormatString    A Null-terminated Unicode format string.
+  @param  ...             Variable argument list whose contents are accessed based on the
+                          format string specified by FormatString.
+  @return The number of Unicode characters in the produced output buffer not including the
+          Null-terminator.
+**/
+
+UINTN
+EFIAPI
+UnicodeSPrint (
+  OUT CHAR16        *StartOfBuffer,
+  IN  UINTN         BufferSize,
+  IN  CONST CHAR16  *FormatString,
+  ...
+  );
+```
+
+Just in case in the same file there is a similar function for ASCII:
+```
+UINTN
+EFIAPI
+AsciiSPrint (
+  OUT CHAR8        *StartOfBuffer,
+  IN  UINTN        BufferSize,
+  IN  CONST CHAR8  *FormatString,
+  ...
+  );
+```
+
+
+So the code inside BootOrder loop now would look like this:
+```
+CHAR16 BootOptionStr[sizeof("Boot####")+1];
+UnicodeSPrint(BootOptionStr, (sizeof("Boot####")+1)*sizeof(CHAR16), L"Boot%04x", BootOrderArray[i]);
+Print(L"%s%s\n", BootOptionStr, (BootOrderArray[i] == *BootCurrent)? L"*" : L"" );
+PrintBootOption(BootOptionStr);
+Print(L"\n");
+```
+
+Don't forget to add `#include <Library/PrintLib.h>` to the start of the file.
+
+
+If we compile our app and execute it under OVMF we would get:
+```
+FS0:\> ShowBootVariables.efi
+Boot0000
+UiApp
+Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331)
+
+Boot0001
+UEFI QEMU DVD-ROM QM00003
+PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)
+
+Boot0002
+UEFI QEMU HARDDISK QM00001
+PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)
+
+Boot0003*
+EFI Internal Shell
+Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(7C04A583-9E3E-4F1C-AD65-E05268D0B4D1)
+
+Boot0004
+UEFI PXEv4 (MAC:525400123456)
+PciRoot(0x0)/Pci(0x3,0x0)/MAC(525400123456,0x1)/IPv4(0.0.0.0)
+```
+
+We are definitely in the UEFI shell, so the `BootCurrent`(="*") is placed correctly.
+
+If you want to know information about the printed GUIDs here it is:
+- `FILE_GUID = 7C04A583-9E3E-4f1c-AD65-E05268D0B4D1 # gUefiShellFileGuid`
+https://github.com/tianocore/edk2/blob/master/ShellPkg/Application/Shell/Shell.inf
+- `FILE_GUID = 462CAA21-7614-4503-836E-8AB6F4662331` - UiApp module is driver for BDS phase
+https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Application/UiApp/UiApp.inf
+
+
+As for the `7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1` it is a GUID for the firmware volume in our OVMF image.
+https://github.com/tianocore/edk2/blob/master/OvmfPkg/OvmfPkgX64.fdf
+
+This *.fdf file lists what drivers/apps are placed in every volume in the image (this includes volumes for SEC, PEI or DXE stages): 
+```
+...
+
+[FV.SECFV]
+FvNameGuid         = 763BED0D-DE9F-48F5-81F1-3E90E1B1A015
+BlockSize          = 0x1000
+FvAlignment        = 16
+...
+INF <...>
+...
+
+[FV.PEIFV]
+FvNameGuid         = 6938079B-B503-4E3D-9D24-B28337A25806
+BlockSize          = 0x10000
+FvAlignment        = 16
+...
+INF <...>
+...
+
+[FV.DXEFV]
+FvForceRebase      = FALSE
+FvNameGuid         = 7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1        ### <---- this is a GUID from our output
+BlockSize          = 0x10000
+FvAlignment        = 16
+...
+INF  ShellPkg/Application/Shell/Shell.inf          <--- this apps are placed in the FV.DXEFV firmware volume
+...
+INF  MdeModulePkg/Application/UiApp/UiApp.inf
+```
+
+For the complete edk2 FDF file specification look at the https://edk2-docs.gitbook.io/edk-ii-fdf-specification/
+
diff --git a/Lesson_15/UefiLessonsPkg/HelloWorld/HelloWorld.c b/Lesson_15/UefiLessonsPkg/HelloWorld/HelloWorld.c
new file mode 100644
index 0000000..1f05899
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/HelloWorld/HelloWorld.c
@@ -0,0 +1,15 @@
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+EFI_STATUS
+EFIAPI
+UefiMain (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  SystemTable->ConOut->OutputString(SystemTable->ConOut, L"Hello World!\n");
+  gST->ConOut->OutputString(gST->ConOut, L"Hello again!\n");
+  Print(L"Bye!\n");
+  return EFI_SUCCESS;
+}
diff --git a/Lesson_15/UefiLessonsPkg/HelloWorld/HelloWorld.inf b/Lesson_15/UefiLessonsPkg/HelloWorld/HelloWorld.inf
new file mode 100644
index 0000000..d65ca2e
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/HelloWorld/HelloWorld.inf
@@ -0,0 +1,18 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = HelloWorld
+  FILE_GUID                      = 2e55fa38-f148-42d3-af90-1be247323e30
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = UefiMain
+
+[Sources]
+  HelloWorld.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+
diff --git a/Lesson_15/UefiLessonsPkg/ImageHandle/ImageHandle.c b/Lesson_15/UefiLessonsPkg/ImageHandle/ImageHandle.c
new file mode 100644
index 0000000..32e9c43
--- /dev/null
+++ b/Lesson_15/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_15/UefiLessonsPkg/ImageHandle/ImageHandle.inf b/Lesson_15/UefiLessonsPkg/ImageHandle/ImageHandle.inf
new file mode 100644
index 0000000..34256ee
--- /dev/null
+++ b/Lesson_15/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
+
diff --git a/Lesson_15/UefiLessonsPkg/ImageInfo/ImageInfo.c b/Lesson_15/UefiLessonsPkg/ImageInfo/ImageInfo.c
new file mode 100644
index 0000000..c45570e
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/ImageInfo/ImageInfo.c
@@ -0,0 +1,44 @@
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+#include <Protocol/LoadedImage.h>
+#include <Library/DevicePathLib.h>
+
+EFI_STATUS
+EFIAPI
+UefiMain (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_STATUS Status;
+  EFI_LOADED_IMAGE_PROTOCOL* LoadedImage;
+
+  Status = gBS->HandleProtocol(
+    ImageHandle,
+    &gEfiLoadedImageProtocolGuid,
+    (VOID **) &LoadedImage
+  );
+
+  if (Status == EFI_SUCCESS) {
+    EFI_DEVICE_PATH_PROTOCOL* DevicePath;
+
+    Status = gBS->HandleProtocol(
+      ImageHandle,
+      &gEfiLoadedImageDevicePathProtocolGuid,
+      (VOID**) &DevicePath
+    );
+
+    if (Status == EFI_SUCCESS) {
+      Print(L"Image device: %s\n", ConvertDevicePathToText(DevicePath, FALSE, TRUE));
+      Print(L"Image file: %s\n",  ConvertDevicePathToText(LoadedImage->FilePath, FALSE, TRUE));	// EFI_DEVICE_PATH_PROTOCOL *FilePath
+      Print(L"Image Base: %X\n", LoadedImage->ImageBase);
+      Print(L"Image Size: %X\n", LoadedImage->ImageSize);
+    } else {
+      Print(L"Can't get EFI_LOADED_IMAGE_PROTOCOL, Status=%r\n", Status);
+    }
+  } else {
+    Print(L"Can't get EFI_DEVICE_PATH_PROTOCOL, Status=%r\n", Status);
+  }
+  return EFI_SUCCESS;
+}
diff --git a/Lesson_15/UefiLessonsPkg/ImageInfo/ImageInfo.inf b/Lesson_15/UefiLessonsPkg/ImageInfo/ImageInfo.inf
new file mode 100644
index 0000000..0ce54a6
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/ImageInfo/ImageInfo.inf
@@ -0,0 +1,22 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = ImageInfo
+  FILE_GUID                      = b68d3472-70c7-4928-841b-6566032e0a23
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = UefiMain
+
+[Sources]
+  ImageInfo.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+
+[Protocols]
+  gEfiLoadedImageProtocolGuid
+  gEfiLoadedImageDevicePathProtocolGuid
+
diff --git a/Lesson_15/UefiLessonsPkg/ListVariables/ListVariables.c b/Lesson_15/UefiLessonsPkg/ListVariables/ListVariables.c
new file mode 100644
index 0000000..1f3ef4a
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/ListVariables/ListVariables.c
@@ -0,0 +1,46 @@
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+
+#include <Library/MemoryAllocationLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+
+INTN EFIAPI ShellAppMain(IN UINTN Argc, IN CHAR16 **Argv)
+{
+  EFI_GUID VendorGuid;
+  UINTN VariableNameSize = sizeof (CHAR16);
+  CHAR16* VariableName = AllocateZeroPool(sizeof(CHAR16));
+  if (VariableName == NULL) {
+    Print(L"Error on AllocateZeroPool call\n");
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  while (TRUE)
+  {
+    UINTN VariableNameSizeOld = VariableNameSize;
+    EFI_STATUS Status = gRT->GetNextVariableName(&VariableNameSize, VariableName, &VendorGuid);
+    if (Status == EFI_SUCCESS) {
+      Print(L"%g: %s\n", VendorGuid, VariableName);
+    } else if (Status == EFI_BUFFER_TOO_SMALL) {
+      VariableName = ReallocatePool(VariableNameSizeOld, VariableNameSize, VariableName);
+      if (VariableName == NULL) {
+        Print(L"Error on ReallocatePool call\n");
+        return EFI_OUT_OF_RESOURCES;
+      }
+      Status = gRT->GetNextVariableName(&VariableNameSize, VariableName, &VendorGuid);
+      if (Status == EFI_SUCCESS) {
+        Print(L"%g: %s\n", VendorGuid, VariableName);
+      } else {
+        Print(L"Error on 'gRT->GetNextVariableName' call: %s\n", Status);
+        return Status;
+      }
+    } else if (Status == EFI_NOT_FOUND) {
+      FreePool(VariableName);
+      return EFI_SUCCESS;
+    } else {
+      Print(L"Error on 'gRT->GetNextVariableName' call: %s\n", Status);
+      return Status;
+    }
+  }
+  return EFI_SUCCESS;
+}
diff --git a/Lesson_15/UefiLessonsPkg/ListVariables/ListVariables.inf b/Lesson_15/UefiLessonsPkg/ListVariables/ListVariables.inf
new file mode 100644
index 0000000..14e9fa2
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/ListVariables/ListVariables.inf
@@ -0,0 +1,19 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = ListVariables
+  FILE_GUID                      = d66f68b2-3591-45af-bf5d-519152b9d877
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = ShellCEntryLib
+
+[Sources]
+  ListVariables.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+  ShellCEntryLib
+
diff --git a/Lesson_15/UefiLessonsPkg/MemoryInfo/MemoryInfo.c b/Lesson_15/UefiLessonsPkg/MemoryInfo/MemoryInfo.c
new file mode 100644
index 0000000..8c3bcf2
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/MemoryInfo/MemoryInfo.c
@@ -0,0 +1,215 @@
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+// for SetMem
+#include <Library/BaseMemoryLib.h>
+
+#include <Protocol/ShellParameters.h> 
+
+const CHAR16 *memory_types[] = { 
+    L"EfiReservedMemoryType", 
+    L"EfiLoaderCode", 
+    L"EfiLoaderData", 
+    L"EfiBootServicesCode", 
+    L"EfiBootServicesData", 
+    L"EfiRuntimeServicesCode", 
+    L"EfiRuntimeServicesData", 
+    L"EfiConventionalMemory", 
+    L"EfiUnusableMemory", 
+    L"EfiACPIReclaimMemory", 
+    L"EfiACPIMemoryNVS", 
+    L"EfiMemoryMappedIO", 
+    L"EfiMemoryMappedIOPortSpace", 
+    L"EfiPalCode",
+    L"EfiPersistentMemory",
+    L"EfiMaxMemoryType"
+};
+
+
+const CHAR16 *memory_types_OS_view[] = { 
+    L"reserved", // L"EfiReservedMemoryType", 
+    L"usable",   // L"EfiLoaderCode", 
+    L"usable",   // L"EfiLoaderData", 
+    L"usable",   // L"EfiBootServicesCode", 
+    L"usable",   // L"EfiBootServicesData", 
+    L"reserved", // L"EfiRuntimeServicesCode", 
+    L"reserved", // L"EfiRuntimeServicesData", 
+    L"usable",   // L"EfiConventionalMemory", 
+    L"reserved", // L"EfiUnusableMemory", 
+    L"ACPI data",// L"EfiACPIReclaimMemory", 
+    L"ACPI NVS", // L"EfiACPIMemoryNVS", 
+    L"reserved", // L"EfiMemoryMappedIO", 
+    L"reserved", // L"EfiMemoryMappedIOPortSpace", 
+    L"reserved", // L"EfiPalCode",
+    L"usable",   // L"EfiPersistentMemory",
+    L"usable",   // L"EfiMaxMemoryType"
+};
+
+
+const CHAR16 * 
+memory_type_to_str(UINT32 type) 
+{ 
+    if (type > sizeof(memory_types)/sizeof(CHAR16 *)) 
+        return L"Unknown"; 
+
+    return memory_types[type]; 
+}
+
+const CHAR16 *
+memory_type_to_str_OS_view(UINT32 type)
+{
+    if (type > sizeof(memory_types_OS_view)/sizeof(CHAR16 *)) 
+        return L"Unknown"; 
+
+    return memory_types_OS_view[type]; 
+}
+
+#define ATTRIBUTE_STR_SIZE 50
+
+#define CHECK_EFI_MEMORY_ATTRIBUTE(attr) if (attrs & EFI_MEMORY_##attr) { \
+                                           StrCpyS(&str[i], ATTRIBUTE_STR_SIZE, L" "#attr); \
+                                           i+=StrLen(L" "#attr); \
+                                         }
+
+const CHAR16 *
+memory_attrs_to_str(CHAR16* str, UINT64 attrs)
+{
+  int i=0;
+  SetMem((VOID *)str, sizeof(str), 0);
+
+  CHECK_EFI_MEMORY_ATTRIBUTE(UC)
+  CHECK_EFI_MEMORY_ATTRIBUTE(WC)
+  CHECK_EFI_MEMORY_ATTRIBUTE(WT)
+  CHECK_EFI_MEMORY_ATTRIBUTE(WB)
+  CHECK_EFI_MEMORY_ATTRIBUTE(UCE)
+  CHECK_EFI_MEMORY_ATTRIBUTE(WP)
+  CHECK_EFI_MEMORY_ATTRIBUTE(RP)
+  CHECK_EFI_MEMORY_ATTRIBUTE(XP)
+  CHECK_EFI_MEMORY_ATTRIBUTE(NV)
+  CHECK_EFI_MEMORY_ATTRIBUTE(MORE_RELIABLE)
+  CHECK_EFI_MEMORY_ATTRIBUTE(RO)
+  CHECK_EFI_MEMORY_ATTRIBUTE(SP)
+  CHECK_EFI_MEMORY_ATTRIBUTE(CPU_CRYPTO)
+  CHECK_EFI_MEMORY_ATTRIBUTE(RUNTIME)
+
+  return str;
+}
+
+EFI_STATUS
+EFIAPI
+UefiMain (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  UINTN MemoryMapSize = 0;
+  EFI_MEMORY_DESCRIPTOR* MemoryMap = NULL;
+  UINTN MapKey;
+  UINTN DescriptorSize;
+  UINT32 DescriptorVersion;
+
+  EFI_STATUS Status;
+
+
+  EFI_SHELL_PARAMETERS_PROTOCOL* ShellParameters;
+
+  Status = gBS->HandleProtocol(
+    ImageHandle,
+    &gEfiShellParametersProtocolGuid,
+    (VOID **) &ShellParameters
+  );
+
+  BOOLEAN full=FALSE;
+  if (Status == EFI_SUCCESS) {
+    if (ShellParameters->Argc == 2) {
+      if (!StrCmp(ShellParameters->Argv[1], L"full")) {
+        full=TRUE;
+      }
+    }
+  }
+
+
+  Status = gBS->GetMemoryMap(
+        &MemoryMapSize,
+        MemoryMap,
+        &MapKey,
+        &DescriptorSize,
+        &DescriptorVersion
+  );
+
+  if (Status == EFI_BUFFER_TOO_SMALL) {
+    Status = gBS->AllocatePool(
+          EfiBootServicesData,
+          MemoryMapSize,
+          (void**)&MemoryMap
+    );
+
+    if (EFI_ERROR(Status)) {
+      Print(L"AllocatePool error: %r\n", Status);
+      return Status;
+    }
+
+    Status = gBS->GetMemoryMap(
+          &MemoryMapSize,
+          MemoryMap,
+          &MapKey,
+          &DescriptorSize,
+          &DescriptorVersion
+    );
+
+    if (!EFI_ERROR(Status))
+    {
+      EFI_MEMORY_DESCRIPTOR* desc = MemoryMap;
+      EFI_MEMORY_DESCRIPTOR* next_desc;
+      int i = 0;
+      while ((UINT8 *)desc < (UINT8 *)MemoryMap + MemoryMapSize) {
+        UINTN PAGE_SIZE = 4096;
+        UINTN mapping_size =(UINTN) desc->NumberOfPages * PAGE_SIZE;
+
+        UINT64 Start = desc->PhysicalStart;
+
+        next_desc = (EFI_MEMORY_DESCRIPTOR *)((UINT8 *)desc + DescriptorSize);
+        if (!full) {
+	  while ((UINT8 *)next_desc < (UINT8 *)MemoryMap + MemoryMapSize) {
+	    mapping_size =(UINTN) desc->NumberOfPages * PAGE_SIZE;
+	    if ((desc->PhysicalStart + mapping_size) == (next_desc->PhysicalStart)) {
+
+              if (desc->Type != next_desc->Type) {
+                if (StrCmp(memory_type_to_str_OS_view(desc->Type), 
+                           memory_type_to_str_OS_view(next_desc->Type)))
+                  break;
+                }
+
+                desc=next_desc;
+	        next_desc = (EFI_MEMORY_DESCRIPTOR *)((UINT8 *)next_desc + DescriptorSize);
+	    } else {
+	        break;
+	    }
+	  }
+        }
+
+        if (full) {
+          CHAR16 str[ATTRIBUTE_STR_SIZE];
+          Print(L"[#%02d] Type: %s  Attr: %s\n", i++, 
+            memory_type_to_str(desc->Type), memory_attrs_to_str(str, desc->Attribute));
+          Print(L"      Phys: %016llx-%016llx\n", Start, Start + mapping_size - 1);
+        }
+        else {
+          Print(L" [mem: %016llx-%016llx] %s\n", Start, desc->PhysicalStart + mapping_size - 1,
+            memory_type_to_str_OS_view(desc->Type) );
+        }
+
+        desc = next_desc;
+      }
+
+      gBS->FreePool(MemoryMap);
+    } else {
+      Print(L"GetMemoryMap with buffer error: %r\n", Status);
+    }
+  } else {
+    Print(L"GetMemoryMap without buffer error: %r\n", Status);
+  }
+
+  return Status;
+}
+
diff --git a/Lesson_15/UefiLessonsPkg/MemoryInfo/MemoryInfo.inf b/Lesson_15/UefiLessonsPkg/MemoryInfo/MemoryInfo.inf
new file mode 100644
index 0000000..777010d
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/MemoryInfo/MemoryInfo.inf
@@ -0,0 +1,21 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = MemoryInfo
+  FILE_GUID                      = d2ce1d65-603e-4b48-b3e1-fe65d5d0bca8
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = UefiMain
+
+[Sources]
+  MemoryInfo.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+
+[Protocols]
+  gEfiShellParametersProtocolGuid
+
diff --git a/Lesson_15/UefiLessonsPkg/ShowBootVariables/ShowBootVariables.c b/Lesson_15/UefiLessonsPkg/ShowBootVariables/ShowBootVariables.c
new file mode 100644
index 0000000..7f6b58c
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/ShowBootVariables/ShowBootVariables.c
@@ -0,0 +1,93 @@
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+#include <Library/MemoryAllocationLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+
+#include <Library/DevicePathLib.h>
+#include <Library/PrintLib.h>
+
+
+EFI_STATUS
+GetNvramVariable( CHAR16   *VariableName,
+                  EFI_GUID *VariableOwnerGuid, 
+                  VOID     **Buffer,
+                  UINTN    *BufferSize)
+{
+    UINTN Size = 0;
+    *BufferSize = 0;
+
+    EFI_STATUS Status = gRT->GetVariable(VariableName, VariableOwnerGuid, NULL, &Size, NULL);
+    if (Status != EFI_BUFFER_TOO_SMALL) {
+        Print(L"Error! 'gRT->GetVariable' call returned %r\n", Status);
+        return Status;
+    }
+
+    *Buffer = AllocateZeroPool(Size);
+    if (!Buffer) {
+        Print(L"Error! 'AllocateZeroPool' call returned %r\n", Status);
+        return EFI_OUT_OF_RESOURCES;
+    }
+
+    Status = gRT->GetVariable(VariableName, VariableOwnerGuid, NULL, &Size, *Buffer);
+    if (Status == EFI_SUCCESS) {
+        *BufferSize = Size;
+    } else {
+        FreePool( *Buffer );
+        *Buffer = NULL;
+    }
+
+    return Status;
+}
+
+
+VOID PrintBootOption(CHAR16* BootOptionName)
+{
+  UINTN OptionSize;
+  UINT8* Buffer;
+ 
+  EFI_STATUS Status = GetNvramVariable(BootOptionName, &gEfiGlobalVariableGuid, (VOID**)&Buffer, &OptionSize);
+  if (Status == EFI_SUCCESS) {
+      EFI_LOAD_OPTION* LoadOption = (EFI_LOAD_OPTION*) Buffer;
+      CHAR16* Description = (CHAR16*)(Buffer + sizeof (EFI_LOAD_OPTION));
+      UINTN DescriptionSize = StrSize(Description);
+
+      Print(L"%s\n", Description);
+      if (LoadOption->FilePathListLength != 0) {
+        VOID* FilePathList = (UINT8 *)Description + DescriptionSize;
+        CHAR16* DevPathString = ConvertDevicePathToText(FilePathList, TRUE, FALSE);
+        Print(L"%s\n", DevPathString);
+      }
+  } else {
+    Print(L"Can't get %s variable\n", BootOptionName);
+  }
+}
+
+
+INTN EFIAPI ShellAppMain(IN UINTN Argc, IN CHAR16 **Argv)
+{
+  UINTN OptionSize;
+  EFI_STATUS Status;
+
+  UINT16* BootCurrent;
+  Status = GetNvramVariable(L"BootCurrent", &gEfiGlobalVariableGuid, (VOID**)&BootCurrent, &OptionSize);
+  if (Status != EFI_SUCCESS) {
+    Print(L"Can't get BootCurrent variable\n");
+  }
+
+  UINT16* BootOrderArray;
+  Status = GetNvramVariable(L"BootOrder", &gEfiGlobalVariableGuid, (VOID**)&BootOrderArray, &OptionSize);
+  if (Status == EFI_SUCCESS) {
+    for (UINTN i=0; i<(OptionSize/sizeof(UINT16)); i++) {
+      CHAR16 BootOptionStr[sizeof("Boot####")+1];
+      UnicodeSPrint(BootOptionStr, (sizeof("Boot####")+1)*sizeof(CHAR16), L"Boot%04x", BootOrderArray[i]);
+      Print(L"%s%s\n", BootOptionStr, (BootOrderArray[i] == *BootCurrent)? L"*" : L"" );
+      PrintBootOption(BootOptionStr);
+      Print(L"\n");
+    }
+  } else {
+    Print(L"Can't get BootOrder variable\n");
+  }
+
+  return EFI_SUCCESS;
+}
diff --git a/Lesson_15/UefiLessonsPkg/ShowBootVariables/ShowBootVariables.inf b/Lesson_15/UefiLessonsPkg/ShowBootVariables/ShowBootVariables.inf
new file mode 100644
index 0000000..d2cfba9
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/ShowBootVariables/ShowBootVariables.inf
@@ -0,0 +1,19 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = ShowBootVariables
+  FILE_GUID                      = 31266d12-9c60-478e-905e-05d117a3a9df
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = ShellCEntryLib
+
+[Sources]
+  ShowBootVariables.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+  ShellCEntryLib
+
diff --git a/Lesson_15/UefiLessonsPkg/SimpleShellApp/SimpleShellApp.c b/Lesson_15/UefiLessonsPkg/SimpleShellApp/SimpleShellApp.c
new file mode 100644
index 0000000..b13aa6c
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/SimpleShellApp/SimpleShellApp.c
@@ -0,0 +1,14 @@
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+INTN EFIAPI ShellAppMain(IN UINTN Argc, IN CHAR16 **Argv)
+{
+//  SystemTable->ConOut->OutputString(SystemTable->ConOut, L"Hello World!\n");
+  gST->ConOut->OutputString(gST->ConOut, L"Hello again!\n");
+  Print(L"Bye!\n");
+
+  for (UINTN i=Argc; i>0; i--) {
+    Print(L"Arg[%d]=%s\n", Argc-i, Argv[Argc-i]);
+  }
+  return 0;
+}
diff --git a/Lesson_15/UefiLessonsPkg/SimpleShellApp/SimpleShellApp.inf b/Lesson_15/UefiLessonsPkg/SimpleShellApp/SimpleShellApp.inf
new file mode 100644
index 0000000..013bf4e
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/SimpleShellApp/SimpleShellApp.inf
@@ -0,0 +1,19 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = SimpleShellApp
+  FILE_GUID                      = 2afd1202-545e-4f8d-b8fb-bc179e84ddc8
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = ShellCEntryLib
+
+[Sources]
+  SimpleShellApp.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+  ShellCEntryLib
+
diff --git a/Lesson_15/UefiLessonsPkg/SimplestApp/SimplestApp.c b/Lesson_15/UefiLessonsPkg/SimplestApp/SimplestApp.c
new file mode 100644
index 0000000..8bdf500
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/SimplestApp/SimplestApp.c
@@ -0,0 +1,10 @@
+EFI_STATUS
+EFIAPI
+UefiMain (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  return EFI_SUCCESS;
+}
+
diff --git a/Lesson_15/UefiLessonsPkg/SimplestApp/SimplestApp.inf b/Lesson_15/UefiLessonsPkg/SimplestApp/SimplestApp.inf
new file mode 100644
index 0000000..7d4bae2
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/SimplestApp/SimplestApp.inf
@@ -0,0 +1,16 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = SimplestApp
+  FILE_GUID                      = 4a298956-fbe0-47fb-ae3a-2d5a0a959a26
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = UefiMain
+
+[Sources]
+  SimplestApp.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
diff --git a/Lesson_15/UefiLessonsPkg/UefiLessonsPkg.dsc b/Lesson_15/UefiLessonsPkg/UefiLessonsPkg.dsc
new file mode 100644
index 0000000..5a3ae1c
--- /dev/null
+++ b/Lesson_15/UefiLessonsPkg/UefiLessonsPkg.dsc
@@ -0,0 +1,36 @@
+[Defines]
+  DSC_SPECIFICATION              = 0x0001001C
+  PLATFORM_GUID                  = 3db7270f-ffac-4139-90a4-0ae68f3f8167
+  PLATFORM_VERSION               = 0.01
+  PLATFORM_NAME                  = UefiLessonsPkg
+  SKUID_IDENTIFIER               = DEFAULT
+  SUPPORTED_ARCHITECTURES        = X64
+  BUILD_TARGETS                  = RELEASE
+
+
+[LibraryClasses]
+  UefiApplicationEntryPoint|MdePkg/Library/UefiApplicationEntryPoint/UefiApplicationEntryPoint.inf
+  UefiBootServicesTableLib|MdePkg/Library/UefiBootServicesTableLib/UefiBootServicesTableLib.inf
+  DebugLib|MdePkg/Library/UefiDebugLibConOut/UefiDebugLibConOut.inf
+  BaseLib|MdePkg/Library/BaseLib/BaseLib.inf
+  PcdLib|MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf
+  BaseMemoryLib|MdePkg/Library/BaseMemoryLib/BaseMemoryLib.inf
+  RegisterFilterLib|MdePkg/Library/RegisterFilterLibNull/RegisterFilterLibNull.inf
+  PrintLib|MdePkg/Library/BasePrintLib/BasePrintLib.inf
+  DebugPrintErrorLevelLib|MdePkg/Library/BaseDebugPrintErrorLevelLib/BaseDebugPrintErrorLevelLib.inf
+  UefiLib|MdePkg/Library/UefiLib/UefiLib.inf
+  MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
+  DevicePathLib|MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.inf
+  UefiRuntimeServicesTableLib|MdePkg/Library/UefiRuntimeServicesTableLib/UefiRuntimeServicesTableLib.inf
+  ShellCEntryLib|ShellPkg/Library/UefiShellCEntryLib/UefiShellCEntryLib.inf
+
+[Components]
+  UefiLessonsPkg/SimplestApp/SimplestApp.inf
+  UefiLessonsPkg/HelloWorld/HelloWorld.inf
+  UefiLessonsPkg/ImageHandle/ImageHandle.inf
+  UefiLessonsPkg/ImageInfo/ImageInfo.inf
+  UefiLessonsPkg/MemoryInfo/MemoryInfo.inf
+  UefiLessonsPkg/SimpleShellApp/SimpleShellApp.inf
+  UefiLessonsPkg/ListVariables/ListVariables.inf
+  UefiLessonsPkg/ShowBootVariables/ShowBootVariables.inf
+
diff --git a/README.md b/README.md
index 161d05b..c34a384 100644
--- a/README.md
+++ b/README.md
@@ -17,4 +17,5 @@ Lessons description:
 - Lesson 12: `EFI_SHELL_PARAMETERS_PROTOCOL`. Transform our EFI memory map to the Linux kernel style
 - Lesson 13: `ShellAppMain` entry point
 - Lesson 14: Get all variable names and GUIDs with the `gRT->GetNextVariableName` API
+- Lesson 15: Get and parse boot variables (BootOrder/BootCurrent/BootXXXX) with the `gRT->GetVariable` API