package/pkg-kconfig.mk - buildroot - Git at Google

 ################################################################################
 # Kconfig package infrastructure
 #
 # This file implements an infrastructure that eases development of
 # package .mk files for packages that use kconfig for configuration files.
 # It is based on the generic-package infrastructure, and inherits all of its
 # features.
 #
 # See the Buildroot documentation for details on the usage of this
 # infrastructure.
 #
 ################################################################################

 ################################################################################
 # inner-kconfig-package -- generates the make targets needed to support a
 # kconfig package
 #
 #  argument 1 is the lowercase package name
 #  argument 2 is the uppercase package name, including a HOST_ prefix
 #             for host packages
 #  argument 3 is the uppercase package name, without the HOST_ prefix
 #             for host packages
 #  argument 4 is the type (target or host)
 ################################################################################

 define inner-kconfig-package

 # Call the generic package infrastructure to generate the necessary
 # make targets.
 # Note: this must be done _before_ attempting to use $$($(2)_DIR) in a
 # dependency expression
 $(call inner-generic-package,$(1),$(2),$(3),$(4))

 # Default values
 $(2)_KCONFIG_EDITORS ?= menuconfig
 $(2)_KCONFIG_OPTS ?=
 $(2)_KCONFIG_FIXUP_CMDS ?=
 $(2)_KCONFIG_FRAGMENT_FILES ?=

 # The config file as well as the fragments could be in-tree, so before
 # depending on them the package should be extracted (and patched) first.
 #
 # Since those files only have a order-only dependency, make would treat
 # any missing one as a "force" target:
 #   https://www.gnu.org/software/make/manual/make.html#Force-Targets
 # and would forcibly any rule that depend on those files, causing a
 # rebuild of the kernel each time make is called.
 #
 # So, we provide a recipe that checks all of those files exist, to
 # overcome that standard make behaviour.
 #
 $$($(2)_KCONFIG_FILE) $$($(2)_KCONFIG_FRAGMENT_FILES): | $(1)-patch
 	for f in $$($(2)_KCONFIG_FILE) $$($(2)_KCONFIG_FRAGMENT_FILES); do \
 		if [ ! -f "$$$${f}" ]; then \
 			printf "Kconfig fragment '%s' for '%s' does not exist\n" "$$$${f}" "$(1)"; \
 			exit 1; \
 		fi; \
 	done

 $(2)_KCONFIG_MAKE = \
 	$$($(2)_MAKE_ENV) $$(MAKE) -C $$($(2)_DIR) $$($(2)_KCONFIG_OPTS)

 # $(2)_KCONFIG_MAKE may already rely on shell expansion. As the $() syntax
 # of the shell conflicts with Make's own syntax, this means that backticks
 # are used with those shell constructs. Unfortunately, the backtick syntax
 # does not nest, and we need to use Make instead of the shell to handle
 # conditions.

 # A recursively expanded variable is necessary, to be sure that the shell
 # command is called when the rule is processed during the build and not
 # when the rule is created when parsing all packages.
 $(2)_KCONFIG_RULES = \
 	$$(shell $$($(2)_KCONFIG_MAKE) -pn config 2>/dev/null | \
 		sed 's/^\([_0-9a-zA-Z]*config\):.*/\1/ p; d')

 # The correct way to regenerate a .config file is to use 'make olddefconfig'.
 # For historical reasons, the target name is 'oldnoconfig' between Linux kernel
 # versions 2.6.36 and 3.6, and remains as an alias in later versions.
 # In older versions, and in some other projects that use kconfig, the target is
 # not supported at all, and we use 'yes "" | make oldconfig' as a fallback
 # only, as this can fail in complex cases.
 define $(2)_REGEN_DOT_CONFIG
 	$$(if $$(filter olddefconfig,$$($(2)_KCONFIG_RULES)),
 		$$(Q)$$($(2)_KCONFIG_MAKE) olddefconfig,
 		$$(if $$(filter oldnoconfig,$$($(2)_KCONFIG_RULES)),
 			$$(Q)$$($(2)_KCONFIG_MAKE) oldnoconfig,
 			$$(Q)(yes "" | $$($(2)_KCONFIG_MAKE) oldconfig)))
 endef

 # The specified source configuration file and any additional configuration file
 # fragments are merged together to .config, after the package has been patched.
 # Since the file could be a defconfig file it needs to be expanded to a
 # full .config first.
 $$($(2)_DIR)/.config: $$($(2)_KCONFIG_FILE) $$($(2)_KCONFIG_FRAGMENT_FILES)
 	$$(Q)$$(if $$($(2)_KCONFIG_DEFCONFIG), \
 		$$($(2)_KCONFIG_MAKE) $$($(2)_KCONFIG_DEFCONFIG), \
 		cp $$($(2)_KCONFIG_FILE) $$(@))
 	$$(Q)support/kconfig/merge_config.sh -m -O $$(@D) \
 		$$(@) $$($(2)_KCONFIG_FRAGMENT_FILES)
 	$$($(2)_REGEN_DOT_CONFIG)

 # If _KCONFIG_FILE or _KCONFIG_FRAGMENT_FILES exists, this dependency is
 # already implied, but if we only have a _KCONFIG_DEFCONFIG we have to add
 # it explicitly. It doesn't hurt to always have it though.
 $$($(2)_DIR)/.config: | $(1)-patch

 # In order to get a usable, consistent configuration, some fixup may be needed.
 # The exact rules are specified by the package .mk file.
 define $(2)_FIXUP_DOT_CONFIG
 	$$($(2)_KCONFIG_FIXUP_CMDS)
 	$$($(2)_REGEN_DOT_CONFIG)
 	$$(Q)touch $$($(2)_DIR)/.stamp_kconfig_fixup_done
 endef

 $$($(2)_DIR)/.stamp_kconfig_fixup_done: $$($(2)_DIR)/.config
 	$$($(2)_FIXUP_DOT_CONFIG)

 # Before running configure, the configuration file should be present and fixed
 $$($(2)_TARGET_CONFIGURE): $$($(2)_DIR)/.stamp_kconfig_fixup_done

 # Only enable the foo-*config targets when the package is actually enabled.
 # Note: the variable $(2)_KCONFIG_VAR is not related to the kconfig
 # infrastructure, but defined by pkg-generic.mk. The generic infrastructure is
 # already called above, so we can effectively use this variable.
 ifeq ($$($$($(2)_KCONFIG_VAR)),y)

 ifeq ($$(BR_BUILDING),y)
 # Either FOO_KCONFIG_FILE or FOO_KCONFIG_DEFCONFIG is required...
 ifeq ($$(or $$($(2)_KCONFIG_FILE),$$($(2)_KCONFIG_DEFCONFIG)),)
 $$(error Internal error: no value specified for $(2)_KCONFIG_FILE or $(2)_KCONFIG_DEFCONFIG)
 endif
 # ... but not both:
 ifneq ($$(and $$($(2)_KCONFIG_FILE),$$($(2)_KCONFIG_DEFCONFIG)),)
 $$(error Internal error: $(2)_KCONFIG_FILE and $(2)_KCONFIG_DEFCONFIG are mutually exclusive but both are defined)
 endif
 endif

 # For the configurators, we do want to use the system-provided host
 # tools, not the ones we build. This is particularly true for
 # pkg-config; if we use our pkg-config (from host-pkgconf), then it
 # would not look for the .pc from the host, but we do need them,
 # especially to find ncurses, GTK+, Qt (resp. for menuconfig and
 # nconfig, gconfig, xconfig).
 # So we simply remove our PATH and PKG_CONFIG_* variables.
 $(2)_CONFIGURATOR_MAKE_ENV = \
 	$$(filter-out PATH=% PKG_CONFIG=% PKG_CONFIG_SYSROOT_DIR=% PKG_CONFIG_LIBDIR=%,$$($(2)_MAKE_ENV))

 # Configuration editors (menuconfig, ...)
 #
 # We need to apply the configuration fixups right after a configuration
 # editor exits, so that it is possible to save the configuration right
 # after exiting an editor, and so the user always sees a .config file
 # that is clean wrt. our requirements.
 #
 # Because commands in $(1)_FIXUP_KCONFIG are probably using $(@D), we
 # need to have a valid @D set. But, because the configurators rules are
 # not real files and do not contain the path to the package build dir,
 # @D would be just '.' in this case. So, we use an intermediate rule
 # with a stamp-like file which path is in the package build dir, so we
 # end up having a valid @D.
 #
 $$(addprefix $(1)-,$$($(2)_KCONFIG_EDITORS)): $(1)-%: $$($(2)_DIR)/.kconfig_editor_%
 $$($(2)_DIR)/.kconfig_editor_%: $$($(2)_DIR)/.stamp_kconfig_fixup_done
 	$$($(2)_CONFIGURATOR_MAKE_ENV) $$(MAKE) -C $$($(2)_DIR) \
 		$$($(2)_KCONFIG_OPTS) $$(*)
 	rm -f $$($(2)_DIR)/.stamp_{kconfig_fixup_done,configured,built}
 	rm -f $$($(2)_DIR)/.stamp_{target,staging,images}_installed
 	$$($(2)_FIXUP_DOT_CONFIG)

 # Saving back the configuration
 #
 # Ideally, that should directly depend on $$($(2)_DIR)/.stamp_kconfig_fixup_done,
 # but that breaks the use-case in PR-8156 (from a clean tree):
 #   make menuconfig           <- enable kernel, use an in-tree defconfig, save and exit
 #   make linux-menuconfig     <- enable/disable whatever option, save and exit
 #   make menuconfig           <- change to use a custom defconfig file, set a path, save and exit
 #   make linux-update-config  <- should save to the new custom defconfig file
 #
 # Because of that use-case, saving the configuration can *not* directly
 # depend on the stamp file, because it itself depends on the .config,
 # which in turn depends on the (newly-set an non-existent) custom
 # defconfig file.
 #
 # Instead, we use an PHONY rule that will catch that situation.
 #
 $(1)-check-configuration-done:
 	@if [ ! -f $$($(2)_DIR)/.stamp_kconfig_fixup_done ]; then \
 		echo "$(1) is not yet configured"; \
 		exit 1; \
 	fi

 $(1)-savedefconfig: $(1)-check-configuration-done
 	$$($(2)_MAKE_ENV) $$(MAKE) -C $$($(2)_DIR) \
 		$$($(2)_KCONFIG_OPTS) savedefconfig

 # Target to copy back the configuration to the source configuration file
 # Even though we could use 'cp --preserve-timestamps' here, the separate
 # cp and 'touch --reference' is used for symmetry with $(1)-update-defconfig.
 $(1)-update-config: $(1)-check-configuration-done
 	@$$(if $$($(2)_KCONFIG_FRAGMENT_FILES), \
 		echo "Unable to perform $(1)-update-config when fragment files are set"; exit 1)
 	@$$(if $$($(2)_KCONFIG_DEFCONFIG), \
 		echo "Unable to perform $(1)-update-config when using a defconfig rule"; exit 1)
 	cp -f $$($(2)_DIR)/.config $$($(2)_KCONFIG_FILE)
 	touch --reference $$($(2)_DIR)/.config $$($(2)_KCONFIG_FILE)

 # Note: make sure the timestamp of the stored configuration is not newer than
 # the .config to avoid a useless rebuild. Note that, contrary to
 # $(1)-update-config, the reference for 'touch' is _not_ the file from which
 # we copy.
 $(1)-update-defconfig: $(1)-savedefconfig
 	@$$(if $$($(2)_KCONFIG_FRAGMENT_FILES), \
 		echo "Unable to perform $(1)-update-defconfig when fragment files are set"; exit 1)
 	@$$(if $$($(2)_KCONFIG_DEFCONFIG), \
 		echo "Unable to perform $(1)-update-defconfig when using a defconfig rule"; exit 1)
 	cp -f $$($(2)_DIR)/defconfig $$($(2)_KCONFIG_FILE)
 	touch --reference $$($(2)_DIR)/.config $$($(2)_KCONFIG_FILE)

 endif # package enabled

 .PHONY: \
 	$(1)-update-config \
 	$(1)-update-defconfig \
 	$(1)-savedefconfig \
 	$(1)-check-configuration-done \
 	$$($(2)_DIR)/.kconfig_editor_% \
 	$$(addprefix $(1)-,$$($(2)_KCONFIG_EDITORS))

 endef # inner-kconfig-package

 ################################################################################
 # kconfig-package -- the target generator macro for kconfig packages
 ################################################################################

 kconfig-package = $(call inner-kconfig-package,$(pkgname),$(call UPPERCASE,$(pkgname)),$(call UPPERCASE,$(pkgname)),target)
	################################################################################
	# Kconfig package infrastructure
	#
	# This file implements an infrastructure that eases development of
	# package .mk files for packages that use kconfig for configuration files.
	# It is based on the generic-package infrastructure, and inherits all of its
	# features.
	#
	# See the Buildroot documentation for details on the usage of this
	# infrastructure.
	#
	################################################################################

	################################################################################
	# inner-kconfig-package -- generates the make targets needed to support a
	# kconfig package
	#
	# argument 1 is the lowercase package name
	# argument 2 is the uppercase package name, including a HOST_ prefix
	# for host packages
	# argument 3 is the uppercase package name, without the HOST_ prefix
	# for host packages
	# argument 4 is the type (target or host)
	################################################################################

	define inner-kconfig-package

	# Call the generic package infrastructure to generate the necessary
	# make targets.
	# Note: this must be done _before_ attempting to use $$($(2)_DIR) in a
	# dependency expression
	$(call inner-generic-package,$(1),$(2),$(3),$(4))

	# Default values
	$(2)_KCONFIG_EDITORS ?= menuconfig
	$(2)_KCONFIG_OPTS ?=
	$(2)_KCONFIG_FIXUP_CMDS ?=
	$(2)_KCONFIG_FRAGMENT_FILES ?=

	# The config file as well as the fragments could be in-tree, so before
	# depending on them the package should be extracted (and patched) first.
	#
	# Since those files only have a order-only dependency, make would treat
	# any missing one as a "force" target:
	# https://www.gnu.org/software/make/manual/make.html#Force-Targets
	# and would forcibly any rule that depend on those files, causing a
	# rebuild of the kernel each time make is called.
	#
	# So, we provide a recipe that checks all of those files exist, to
	# overcome that standard make behaviour.
	#
	$$($(2)_KCONFIG_FILE) $$($(2)_KCONFIG_FRAGMENT_FILES): \| $(1)-patch
	for f in $$($(2)_KCONFIG_FILE) $$($(2)_KCONFIG_FRAGMENT_FILES); do \
	if [ ! -f "$$$${f}" ]; then \
	printf "Kconfig fragment '%s' for '%s' does not exist\n" "$$$${f}" "$(1)"; \
	exit 1; \
	fi; \
	done

	$(2)_KCONFIG_MAKE = \
	$$($(2)_MAKE_ENV) $$(MAKE) -C $$($(2)_DIR) $$($(2)_KCONFIG_OPTS)

	# $(2)_KCONFIG_MAKE may already rely on shell expansion. As the $() syntax
	# of the shell conflicts with Make's own syntax, this means that backticks
	# are used with those shell constructs. Unfortunately, the backtick syntax
	# does not nest, and we need to use Make instead of the shell to handle
	# conditions.

	# A recursively expanded variable is necessary, to be sure that the shell
	# command is called when the rule is processed during the build and not
	# when the rule is created when parsing all packages.
	$(2)_KCONFIG_RULES = \
	$$(shell $$($(2)_KCONFIG_MAKE) -pn config 2>/dev/null \| \
	sed 's/^\([_0-9a-zA-Z]config\):./\1/ p; d')

	# The correct way to regenerate a .config file is to use 'make olddefconfig'.
	# For historical reasons, the target name is 'oldnoconfig' between Linux kernel
	# versions 2.6.36 and 3.6, and remains as an alias in later versions.
	# In older versions, and in some other projects that use kconfig, the target is
	# not supported at all, and we use 'yes "" \| make oldconfig' as a fallback
	# only, as this can fail in complex cases.
	define $(2)_REGEN_DOT_CONFIG
	$$(if $$(filter olddefconfig,$$($(2)_KCONFIG_RULES)),
	$$(Q)$$($(2)_KCONFIG_MAKE) olddefconfig,
	$$(if $$(filter oldnoconfig,$$($(2)_KCONFIG_RULES)),
	$$(Q)$$($(2)_KCONFIG_MAKE) oldnoconfig,
	$$(Q)(yes "" \| $$($(2)_KCONFIG_MAKE) oldconfig)))
	endef

	# The specified source configuration file and any additional configuration file
	# fragments are merged together to .config, after the package has been patched.
	# Since the file could be a defconfig file it needs to be expanded to a
	# full .config first.
	$$($(2)_DIR)/.config: $$($(2)_KCONFIG_FILE) $$($(2)_KCONFIG_FRAGMENT_FILES)
	$$(Q)$$(if $$($(2)_KCONFIG_DEFCONFIG), \
	$$($(2)_KCONFIG_MAKE) $$($(2)_KCONFIG_DEFCONFIG), \
	cp $$($(2)_KCONFIG_FILE) $$(@))
	$$(Q)support/kconfig/merge_config.sh -m -O $$(@D) \
	$$(@) $$($(2)_KCONFIG_FRAGMENT_FILES)
	$$($(2)_REGEN_DOT_CONFIG)

	# If _KCONFIG_FILE or _KCONFIG_FRAGMENT_FILES exists, this dependency is
	# already implied, but if we only have a _KCONFIG_DEFCONFIG we have to add
	# it explicitly. It doesn't hurt to always have it though.
	$$($(2)_DIR)/.config: \| $(1)-patch

	# In order to get a usable, consistent configuration, some fixup may be needed.
	# The exact rules are specified by the package .mk file.
	define $(2)_FIXUP_DOT_CONFIG
	$$($(2)_KCONFIG_FIXUP_CMDS)
	$$($(2)_REGEN_DOT_CONFIG)
	$$(Q)touch $$($(2)_DIR)/.stamp_kconfig_fixup_done
	endef

	$$($(2)_DIR)/.stamp_kconfig_fixup_done: $$($(2)_DIR)/.config
	$$($(2)_FIXUP_DOT_CONFIG)

	# Before running configure, the configuration file should be present and fixed
	$$($(2)_TARGET_CONFIGURE): $$($(2)_DIR)/.stamp_kconfig_fixup_done

	# Only enable the foo-*config targets when the package is actually enabled.
	# Note: the variable $(2)_KCONFIG_VAR is not related to the kconfig
	# infrastructure, but defined by pkg-generic.mk. The generic infrastructure is
	# already called above, so we can effectively use this variable.
	ifeq ($$($$($(2)_KCONFIG_VAR)),y)

	ifeq ($$(BR_BUILDING),y)
	# Either FOO_KCONFIG_FILE or FOO_KCONFIG_DEFCONFIG is required...
	ifeq ($$(or $$($(2)_KCONFIG_FILE),$$($(2)_KCONFIG_DEFCONFIG)),)
	$$(error Internal error: no value specified for $(2)_KCONFIG_FILE or $(2)_KCONFIG_DEFCONFIG)
	endif
	# ... but not both:
	ifneq ($$(and $$($(2)_KCONFIG_FILE),$$($(2)_KCONFIG_DEFCONFIG)),)
	$$(error Internal error: $(2)_KCONFIG_FILE and $(2)_KCONFIG_DEFCONFIG are mutually exclusive but both are defined)
	endif
	endif

	# For the configurators, we do want to use the system-provided host
	# tools, not the ones we build. This is particularly true for
	# pkg-config; if we use our pkg-config (from host-pkgconf), then it
	# would not look for the .pc from the host, but we do need them,
	# especially to find ncurses, GTK+, Qt (resp. for menuconfig and
	# nconfig, gconfig, xconfig).
	# So we simply remove our PATH and PKG_CONFIG_* variables.
	$(2)_CONFIGURATOR_MAKE_ENV = \
	$$(filter-out PATH=% PKG_CONFIG=% PKG_CONFIG_SYSROOT_DIR=% PKG_CONFIG_LIBDIR=%,$$($(2)_MAKE_ENV))

	# Configuration editors (menuconfig, ...)
	#
	# We need to apply the configuration fixups right after a configuration
	# editor exits, so that it is possible to save the configuration right
	# after exiting an editor, and so the user always sees a .config file
	# that is clean wrt. our requirements.
	#
	# Because commands in $(1)_FIXUP_KCONFIG are probably using $(@D), we
	# need to have a valid @D set. But, because the configurators rules are
	# not real files and do not contain the path to the package build dir,
	# @D would be just '.' in this case. So, we use an intermediate rule
	# with a stamp-like file which path is in the package build dir, so we
	# end up having a valid @D.
	#
	$$(addprefix $(1)-,$$($(2)_KCONFIG_EDITORS)): $(1)-%: $$($(2)_DIR)/.kconfig_editor_%
	$$($(2)_DIR)/.kconfig_editor_%: $$($(2)_DIR)/.stamp_kconfig_fixup_done
	$$($(2)_CONFIGURATOR_MAKE_ENV) $$(MAKE) -C $$($(2)_DIR) \
	$$($(2)_KCONFIG_OPTS) $$(*)
	rm -f $$($(2)_DIR)/.stamp_{kconfig_fixup_done,configured,built}
	rm -f $$($(2)_DIR)/.stamp_{target,staging,images}_installed
	$$($(2)_FIXUP_DOT_CONFIG)

	# Saving back the configuration
	#
	# Ideally, that should directly depend on $$($(2)_DIR)/.stamp_kconfig_fixup_done,
	# but that breaks the use-case in PR-8156 (from a clean tree):
	# make menuconfig <- enable kernel, use an in-tree defconfig, save and exit
	# make linux-menuconfig <- enable/disable whatever option, save and exit
	# make menuconfig <- change to use a custom defconfig file, set a path, save and exit
	# make linux-update-config <- should save to the new custom defconfig file
	#
	# Because of that use-case, saving the configuration can not directly
	# depend on the stamp file, because it itself depends on the .config,
	# which in turn depends on the (newly-set an non-existent) custom
	# defconfig file.
	#
	# Instead, we use an PHONY rule that will catch that situation.
	#
	$(1)-check-configuration-done:
	@if [ ! -f $$($(2)_DIR)/.stamp_kconfig_fixup_done ]; then \
	echo "$(1) is not yet configured"; \
	exit 1; \
	fi

	$(1)-savedefconfig: $(1)-check-configuration-done
	$$($(2)_MAKE_ENV) $$(MAKE) -C $$($(2)_DIR) \
	$$($(2)_KCONFIG_OPTS) savedefconfig

	# Target to copy back the configuration to the source configuration file
	# Even though we could use 'cp --preserve-timestamps' here, the separate
	# cp and 'touch --reference' is used for symmetry with $(1)-update-defconfig.
	$(1)-update-config: $(1)-check-configuration-done
	@$$(if $$($(2)_KCONFIG_FRAGMENT_FILES), \
	echo "Unable to perform $(1)-update-config when fragment files are set"; exit 1)
	@$$(if $$($(2)_KCONFIG_DEFCONFIG), \
	echo "Unable to perform $(1)-update-config when using a defconfig rule"; exit 1)
	cp -f $$($(2)_DIR)/.config $$($(2)_KCONFIG_FILE)
	touch --reference $$($(2)_DIR)/.config $$($(2)_KCONFIG_FILE)

	# Note: make sure the timestamp of the stored configuration is not newer than
	# the .config to avoid a useless rebuild. Note that, contrary to
	# $(1)-update-config, the reference for 'touch' is _not_ the file from which
	# we copy.
	$(1)-update-defconfig: $(1)-savedefconfig
	@$$(if $$($(2)_KCONFIG_FRAGMENT_FILES), \
	echo "Unable to perform $(1)-update-defconfig when fragment files are set"; exit 1)
	@$$(if $$($(2)_KCONFIG_DEFCONFIG), \
	echo "Unable to perform $(1)-update-defconfig when using a defconfig rule"; exit 1)
	cp -f $$($(2)_DIR)/defconfig $$($(2)_KCONFIG_FILE)
	touch --reference $$($(2)_DIR)/.config $$($(2)_KCONFIG_FILE)

	endif # package enabled

	.PHONY: \
	$(1)-update-config \
	$(1)-update-defconfig \
	$(1)-savedefconfig \
	$(1)-check-configuration-done \
	$$($(2)_DIR)/.kconfig_editor_% \
	$$(addprefix $(1)-,$$($(2)_KCONFIG_EDITORS))

	endef # inner-kconfig-package

	################################################################################
	# kconfig-package -- the target generator macro for kconfig packages
	################################################################################

	kconfig-package = $(call inner-kconfig-package,$(pkgname),$(call UPPERCASE,$(pkgname)),$(call UPPERCASE,$(pkgname)),target)