if (NOT DEFINED KDIR)
	set(KDIR "/usr/src/linux")
endif (NOT DEFINED KDIR)

# Try to figure out the kernel release once so we can show it before building.
execute_process(
	COMMAND make -s -C ${KDIR} kernelrelease
	RESULT_VARIABLE IPOE_KERNEL_RELEASE_RESULT
	OUTPUT_VARIABLE IPOE_KERNEL_RELEASE
	OUTPUT_STRIP_TRAILING_WHITESPACE
	ERROR_QUIET
)

if (NOT IPOE_KERNEL_RELEASE_RESULT STREQUAL "0" OR IPOE_KERNEL_RELEASE STREQUAL "")
	find_program(UNAME_EXECUTABLE uname)

	if (UNAME_EXECUTABLE)
		execute_process(
			COMMAND ${UNAME_EXECUTABLE} -r
			OUTPUT_VARIABLE IPOE_KERNEL_RELEASE
			OUTPUT_STRIP_TRAILING_WHITESPACE
		)
	else()
		set(IPOE_KERNEL_RELEASE "unknown")
	endif()
endif()

ADD_CUSTOM_COMMAND(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/driver/ipoe.ko
	COMMAND rm -rf ${CMAKE_CURRENT_BINARY_DIR}/driver
	COMMAND mkdir ${CMAKE_CURRENT_BINARY_DIR}/driver
	COMMAND ln -sf ${CMAKE_CURRENT_SOURCE_DIR}/* ${CMAKE_CURRENT_BINARY_DIR}/driver
	COMMAND ln -sf ${CMAKE_BINARY_DIR}/version.h ${CMAKE_CURRENT_BINARY_DIR}/driver
	COMMAND ${CMAKE_COMMAND} -E echo "[ 99%] Generating driver/ipoe.ko for kernel ${IPOE_KERNEL_RELEASE}"
	COMMAND make -C ${KDIR} M=${CMAKE_CURRENT_BINARY_DIR}/driver modules
	DEPENDS ipoe.c ipoe.h
)

ADD_CUSTOM_TARGET(ipoe_drv ALL
	DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/driver/ipoe.ko
)

IF (NOT DEFINED CPACK_TYPE)
	INSTALL(CODE "EXECUTE_PROCESS(COMMAND make -C ${KDIR} M=${CMAKE_CURRENT_BINARY_DIR}/drivers/ipoe modules_install)")
ENDIF()