# 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 scripts/Kbuild.include
  
  srcdir        := $(srctree)/$(obj)

  
  # When make is run under a fakechroot environment, the function
  # $(wildcard $(srcdir)/*/.) doesn't only return directories, but also regular
  # files. So, we are using a combination of sort/dir/wildcard which works
  # with fakechroot.
  subdirs       := $(patsubst $(srcdir)/%/,%,\
  		 $(filter-out $(srcdir)/,\
  		 $(sort $(dir $(wildcard $(srcdir)/*/)))))

  # Recursion
  __headers: $(subdirs)
  
  .PHONY: $(subdirs)
  $(subdirs):

  	$(Q)$(MAKE) $(hdr-inst)=$(obj)/$@ dst=$(dst)/$@

  
  # Skip header install/check for include/uapi and arch/$(hdr-arch)/include/uapi.
  # We have only sub-directories there.
  skip-inst := $(if $(filter %/uapi,$(obj)),1)
  
  ifeq ($(skip-inst),)

  # Kbuild file is optional

  kbuild-file := $(srctree)/$(obj)/Kbuild

  -include $(kbuild-file)

  installdir    := $(INSTALL_HDR_PATH)/$(dst)

  gendir        := $(objtree)/$(subst include/,include/generated/,$(obj))

  header-files  := $(notdir $(wildcard $(srcdir)/*.h))
  header-files  += $(notdir $(wildcard $(srcdir)/*.agh))
  header-files  := $(filter-out $(no-export-headers), $(header-files))
  genhdr-files  := $(notdir $(wildcard $(gendir)/*.h))
  genhdr-files  := $(filter-out $(header-files), $(genhdr-files))

  # files used to track state of install/check

  install-file  := $(installdir)/.install
  check-file    := $(installdir)/.check

  # all headers files for this dir

  all-files     := $(header-files) $(genhdr-files)

  output-files  := $(addprefix $(installdir)/, $(all-files))

  ifneq ($(mandatory-y),)
  missing       := $(filter-out $(all-files),$(mandatory-y))
  ifneq ($(missing),)
  $(error Some mandatory headers ($(missing)) are missing in $(obj))
  endif
  endif

  # Work out what needs to be removed

  oldheaders    := $(patsubst $(installdir)/%,%,$(wildcard $(installdir)/*.h))

  unwanted      := $(filter-out $(all-files),$(oldheaders))

  # Prefix unwanted with full paths to $(INSTALL_HDR_PATH)

  unwanted-file := $(addprefix $(installdir)/, $(unwanted))

  printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))

  quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
                              file$(if $(word 2, $(all-files)),s))

        cmd_install = \

          $(CONFIG_SHELL) $< $(installdir) $(srcdir) $(header-files); \
          $(CONFIG_SHELL) $< $(installdir) $(gendir) $(genhdr-files); \

          touch $@

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

  quiet_cmd_check = CHECK   $(printdir) ($(words $(all-files)) files)

  # Headers list can be pretty long, xargs helps to avoid
  # the "Argument list too long" error.
        cmd_check = for f in $(all-files); do                          \

                    echo "$(installdir)/$${f}"; done                      \

                    | xargs                                            \
                    $(PERL) $< $(INSTALL_HDR_PATH)/include $(SRCARCH); \

  	          touch $@

  ifndef HDRCHECK
  # Rules for installing headers

  __headers: $(install-file)

  	@:

  targets += $(install-file)

  $(install-file): scripts/headers_install.sh \

  		 $(addprefix $(srcdir)/,$(header-files)) \
  		 $(addprefix $(gendir)/,$(genhdr-files)) FORCE

  	$(if $(unwanted),$(call cmd,remove),)
  	$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
  	$(call if_changed,install)

  else

  __headers: $(check-file)

  	@:

  targets += $(check-file)
  $(check-file): scripts/headers_check.pl $(output-files) FORCE
  	$(call if_changed,check)

  endif

  targets := $(wildcard $(sort $(targets)))
  cmd_files := $(wildcard \
               $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))

  ifneq ($(cmd_files),)
  	include $(cmd_files)

  endif

  endif # skip-inst

  .PHONY: $(PHONY)
  PHONY += FORCE
  FORCE: ;