# SPDX-License-Identifier: GPL-2.0
# ==========================================================================
# Installing headers
#
# All headers under include/uapi, include/generated/uapi,
# arch/<arch>/include/uapi and arch/<arch>/include/generated/uapi are
# exported.
# They are preprocessed to remove __KERNEL__ section of the file.
#
# ==========================================================================

PHONY := __headers
__headers:

include $(srctree)/scripts/Kbuild.include

src := $(srctree)/$(obj)
gen := $(objtree)/$(subst include/,include/generated/,$(obj))
dst := usr/include

-include $(src)/Kbuild

# $(filter %/, ...) is a workaround for GNU Make <= 4.2.1, where
# $(wildcard $(src)/*/) contains not only directories but also regular files.
src-subdirs := $(patsubst $(src)/%/,%,$(filter %/, $(wildcard $(src)/*/)))
gen-subdirs := $(patsubst $(gen)/%/,%,$(filter %/, $(wildcard $(gen)/*/)))
all-subdirs := $(sort $(src-subdirs) $(gen-subdirs))

src-headers := $(if $(src-subdirs), $(shell cd $(src) && find $(src-subdirs) -name '*.h'))
src-headers := $(filter-out $(no-export-headers), $(src-headers))
gen-headers := $(if $(gen-subdirs), $(shell cd $(gen) && find $(gen-subdirs) -name '*.h'))
gen-headers := $(filter-out $(no-export-headers), $(gen-headers))

# If the same header is exported from source and generated directories,
# the former takes precedence, but this should be warned.
duplicated := $(filter $(gen-headers), $(src-headers))
$(if $(duplicated), $(warning duplicated header export: $(duplicated)))

gen-headers := $(filter-out $(duplicated), $(gen-headers))

# Add dst path prefix
all-subdirs := $(addprefix $(dst)/, $(all-subdirs))
src-headers := $(addprefix $(dst)/, $(src-headers))
gen-headers := $(addprefix $(dst)/, $(gen-headers))
all-headers := $(src-headers) $(gen-headers)

# Work out what needs to be removed
old-subdirs := $(wildcard $(all-subdirs))
old-headers := $(if $(old-subdirs),$(shell find $(old-subdirs) -name '*.h'))
unwanted    := $(filter-out $(all-headers), $(old-headers))

# Create directories
existing-dirs := $(sort $(dir $(old-headers)))
wanted-dirs   := $(sort $(dir $(all-headers)))
new-dirs      := $(filter-out $(existing-dirs), $(wanted-dirs))
$(if $(new-dirs), $(shell mkdir -p $(new-dirs)))

# Rules
quiet_cmd_install = HDRINST $@
      cmd_install = $(CONFIG_SHELL) $(srctree)/scripts/headers_install.sh $< $@

$(src-headers): $(dst)/%.h: $(src)/%.h $(srctree)/scripts/headers_install.sh FORCE
	$(call if_changed,install)

$(gen-headers): $(dst)/%.h: $(gen)/%.h $(srctree)/scripts/headers_install.sh FORCE
	$(call if_changed,install)

quiet_cmd_remove = REMOVE  $(unwanted)
      cmd_remove = rm -f $(unwanted)

__headers: $(all-headers)
ifneq ($(unwanted),)
	$(call cmd,remove)
endif
	@:

existing-headers := $(filter $(old-headers), $(all-headers))

-include $(foreach f,$(existing-headers),$(dir $(f)).$(notdir $(f)).cmd)

PHONY += FORCE
FORCE:

.PHONY: $(PHONY)