# $Id: Makefile.include.header 76553 2019-01-01 01:45:53Z vboxsync $
## @file
# VirtualBox Guest Additions kernel module Makefile, common parts.
#
# (For 2.6.x, the main file must be called 'Makefile'!)
#

#
# Copyright (C) 2006-2019 Oracle Corporation
#
# This file is part of VirtualBox Open Source Edition (OSE), as
# available from http://www.virtualbox.org. This file is free software;
# you can redistribute it and/or modify it under the terms of the GNU
# General Public License (GPL) as published by the Free Software
# Foundation, in version 2 as it comes in the "COPYING" file of the
# VirtualBox OSE distribution. VirtualBox OSE is distributed in the
# hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
#

# Testing:
# * Building with KERN_DIR set uses the value specified and
#   the default value for the unspecified one if any.

#
# These file should be included by the Makefiles for any kernel modules we
# build as part of the Guest Additions.  The intended way of doing this is as
# follows:
#
# # Linux kbuild sets this to our source directory if we are called from
# # there
# obj ?= $(CURDIR)
# include $(obj)/Makefile.include.header
# MOD_NAME = <name of the module to be built, without extension>
# MOD_OBJS = <list of object files which should be included>
# MOD_DEFS = <any additional defines which this module needs>
# MOD_INCL = <any additional include paths which this module needs>
# MOD_CFLAGS = <any additional CFLAGS which this module needs>
# include $(obj)/Makefile.include.footer
#
# The kmk kBuild define KBUILD_TARGET_ARCH is available.
#


#
# First, figure out which architecture we're targeting and the build type.
# (We have to support basic cross building (ARCH=i386|x86_64).)
# While at it, warn about BUILD_* vars found to help with user problems.
#
ifeq ($(filter-out x86_64 amd64 AMD64,$(shell uname -m)),)
 BUILD_TARGET_ARCH_DEF := amd64
else
 BUILD_TARGET_ARCH_DEF := x86
endif
ifneq ($(filter-out amd64 x86,$(BUILD_TARGET_ARCH)),)
 $(warning Ignoring unknown BUILD_TARGET_ARCH value '$(BUILD_TARGET_ARCH)'.)
 BUILD_TARGET_ARCH :=
endif
ifeq ($(BUILD_TARGET_ARCH),)
 ifeq ($(ARCH),x86_64)
  BUILD_TARGET_ARCH := amd64
 else
  ifeq ($(ARCH),i386)
   BUILD_TARGET_ARCH := x86
  else
   BUILD_TARGET_ARCH := $(BUILD_TARGET_ARCH_DEF)
  endif
 endif
else
 ifneq ($(BUILD_TARGET_ARCH),$(BUILD_TARGET_ARCH_DEF))
  $(warning Using BUILD_TARGET_ARCH='$(BUILD_TARGET_ARCH)' from the $(origin BUILD_TARGET_ARCH).)
 endif
endif

ifneq ($(filter-out release profile debug strict,$(BUILD_TYPE)),)
 $(warning Ignoring unknown BUILD_TYPE value '$(BUILD_TYPE)'.)
 BUILD_TYPE :=
endif
ifeq ($(BUILD_TYPE),)
 BUILD_TYPE := release
else
 ifneq ($(BUILD_TYPE),release)
  $(warning Using BUILD_TYPE='$(BUILD_TYPE)' from the $(origin BUILD_TYPE).)
 endif
endif
ifeq ($(USERNAME),)
 USERNAME := noname
endif

ifeq ($(KERNELRELEASE),)

 #
 # building from this directory
 #

 # kernel base directory
 ifdef KERN_DIR
  ifndef KERN_VER
   ifeq ($(filter %/build,$(KERN_DIR)),)
    $(error The variable KERN_DIR must be a kernel build folder and end with /build without a trailing slash, or KERN_VER must be set)
   endif
  endif
 endif

 ifndef KERN_VER
  ifdef KERN_DIR
   KERN_VER = $(notdir $(patsubst %/build,%,$(KERN_DIR)))
   ifeq ($(shell expr $(KERN_VER) : '[0-9]*\.[0-9]*.[0-9]*'),0)
    $(error The kernel build folder path must end in <version>/build, or the variable KERN_VER must be set)
   endif
  endif
 KERN_VER ?= $(shell uname -r)
 endif

 # guess kernel major version (24 or later)
 ifeq ($(shell if grep '"2\.4\.' /lib/modules/$(KERN_VER)/build/include/linux/version.h > /dev/null 2>&1; then echo yes; fi),yes)
  KERN_VERSION := 24
 else
  KERN_VERSION := 26
 endif

else # neq($(KERNELRELEASE),)

 #
 # building from kbuild (make -C <kernel_directory> M=`pwd`)
 #

 # guess kernel version (24 or 26)
 ifeq ($(shell if echo "$(VERSION).$(PATCHLEVEL)." | grep '2\.4\.' > /dev/null; then echo yes; fi),yes)
  KERN_VERSION := 24
 else
  KERN_VERSION := 26
 endif

 KERN_VER := $(KERNELRELEASE)

endif # neq($(KERNELRELEASE),)

# Kernel build folder
ifeq ($(KERN_DIR),)
 KERN_DIR := /lib/modules/$(KERN_VER)/build
endif
ifneq ($(shell if test -d $(KERN_DIR); then echo yes; fi),yes)
 $(error Error: unable to find the headers of the Linux kernel to build against. \
          Specify KERN_VER=<version> (currently $(KERN_VER)) and run Make again)
endif
# Kernel include folder
KERN_INCL := $(KERN_DIR)/include
# module install folder
INSTALL_MOD_DIR ?= misc
MODULE_DIR := $(INSTALL_MOD_PATH)/lib/modules/$(KERN_VER)/$(INSTALL_MOD_DIR)

# debug - show guesses.
ifdef DEBUG
$(warning dbg: INSTALL_MOD_PATH = $(INSTALL_MOD_PATH))
$(warning dbg: INSTALL_MOD_DIR  = $(INSTALL_MOD_DIR))
$(warning dbg: KERN_DIR         = $(KERN_DIR))
$(warning dbg: KERN_INCL        = $(KERN_INCL))
$(warning dbg: KERN_VERSION     = $(KERN_VERSION))
$(warning dbg: MODULE_DIR       = $(MODULE_DIR))
endif