#
# VirtualBox Guest Additions kernel module Makefile, common parts.
#
# (For 2.6.x, the main file must be called 'Makefile'!)
#
# Copyright (C) 2006-2015 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.
#

#
# 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>
# MOD_CLEAN = <list of directories that the clean target should look at>
# 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

ifneq ($(MAKECMDGOALS),clean)

ifeq ($(KERNELRELEASE),)

 #
 # building from this directory
 #

 # kernel base directory
 ifndef KERN_DIR
  KERN_DIR := /lib/modules/$(shell uname -r)/build
  ifneq ($(shell if test -d $(KERN_DIR); then echo yes; fi),yes)
   KERN_DIR := /usr/src/linux
   ifneq ($(shell if test -d $(KERN_DIR); then echo yes; fi),yes)
    $(error Error: unable to find the sources of your current Linux kernel. \
	           Specify KERN_DIR=<directory> and run Make again)
   endif
   $(warning Warning: using /usr/src/linux as the source directory of your \
                      Linux kernel. If this is not correct, specify \
		      KERN_DIR=<directory> and run Make again.)
  endif
 else
  ifneq ($(shell if test -d $(KERN_DIR); then echo yes; fi),yes)
   $(error Error: KERN_DIR does not point to a directory)
  endif
 endif

 # includes
 ifndef KERN_INCL
  KERN_INCL = $(KERN_DIR)/include
 endif
 ifneq ($(shell if test -d $(KERN_INCL); then echo yes; fi),yes)
  $(error Error: unable to find the include directory for your current Linux \
                 kernel. Specify KERN_INCL=<directory> and run Make again)
 endif

 # module install dir, only for current kernel
 ifneq ($(filter install install_rpm,$(MAKECMDGOALS)),)
  ifndef MODULE_DIR
   MODULE_DIR_TST := /lib/modules/$(shell uname -r)
   ifeq ($(shell if test -d $(MODULE_DIR_TST); then echo yes; fi),yes)
    MODULE_DIR := $(MODULE_DIR_TST)/misc
   else
    $(error Unable to find the folder to install the module to)
   endif
  endif # MODULE_DIR unspecified
 endif

 # guess kernel version (24 or 26)
 ifeq ($(shell if grep '"2\.4\.' $(KERN_INCL)/linux/version.h > /dev/null; 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

endif # neq($(KERNELRELEASE),)

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

endif # eq($(MAKECMDGOALS),clean)