linux/scripts/package/debian/rules

#!/usr/bin/make -f
# SPDX-License-Identifier: GPL-2.0-only

# in case debian/rules is executed directly
export DEB_RULES_REQUIRES_ROOT := no

include debian/rules.vars

ifneq (,$(filter-out parallel=1,$(filter parallel=%,$(DEB_BUILD_OPTIONS))))
    NUMJOBS = $(patsubst parallel=%,%,$(filter parallel=%,$(DEB_BUILD_OPTIONS)))
    MAKEFLAGS += -j$(NUMJOBS)
endif

# When KBUILD_VERBOSE is undefined (presumably you are directly working with
# the debianized tree), show verbose logs unless DEB_BUILD_OPTION=terse is set.
ifeq ($(origin KBUILD_VERBOSE),undefined)
    ifeq (,$(filter terse,$(DEB_BUILD_OPTIONS)))
        export KBUILD_VERBOSE := 1
    else
        Q := @
    endif
endif

revision = $(lastword $(subst -, ,$(shell dpkg-parsechangelog -S Version)))
CROSS_COMPILE ?= $(filter-out $(DEB_BUILD_GNU_TYPE)-, $(DEB_HOST_GNU_TYPE)-)
make-opts = ARCH=$(ARCH) KERNELRELEASE=$(KERNELRELEASE) KBUILD_BUILD_VERSION=$(revision) $(addprefix CROSS_COMPILE=,$(CROSS_COMPILE))

binary-targets := $(addprefix binary-, image image-dbg headers libc-dev)

all-packages = $(shell dh_listpackages)
image-package = $(filter linux-image-% user-%, $(filter-out %-dbg, $(all-packages)))
image-dbg-package = $(filter %-dbg, $(all-packages))
libc-dev-package = $(filter linux-libc-dev, $(all-packages))
headers-package = $(filter linux-headers-%, $(all-packages))

mk-files = $(patsubst binary-%,debian/%.files,$1)
package = $($(@:binary-%=%-package))

# DH_OPTION is an environment variable common for all debhelper commands.
# We could 'export' it, but here it is passed from the command line to clarify
# which package is being processed in the build log.
DH_OPTIONS = -p$(package)

define binary
	$(Q)dh_testdir $(DH_OPTIONS)
	$(Q)dh_testroot $(DH_OPTIONS)
	$(Q)dh_prep $(DH_OPTIONS)
	$(Q)+$(MAKE) $(make-opts) run-command KBUILD_RUN_COMMAND='+$$(srctree)/scripts/package/builddeb $(package)'
	$(Q)dh_installdocs $(DH_OPTIONS)
	$(Q)dh_installchangelogs $(DH_OPTIONS)
	$(Q)dh_compress $(DH_OPTIONS)
	$(Q)dh_fixperms $(DH_OPTIONS)
	$(Q)dh_gencontrol $(DH_OPTIONS) -- -f$(call mk-files,$@)
	$(Q)dh_md5sums $(DH_OPTIONS)
	$(Q)dh_builddeb $(DH_OPTIONS) -- $(addprefix -Z,$(KDEB_COMPRESS))
endef

.PHONY: $(binary-targets)
$(binary-targets): build-arch
	$(Q)truncate -s0 $(call mk-files,$@)
	$(if $(package),$(binary))

.PHONY: binary binary-indep binary-arch
binary: binary-arch binary-indep
binary-indep: build-indep
binary-arch: $(binary-targets)
	$(Q)cat $(call mk-files,$^) > debian/files

.PHONY: build build-indep build-arch
build: build-arch build-indep
build-indep:
build-arch:
	$(Q)$(MAKE) $(make-opts) olddefconfig
	$(Q)$(MAKE) $(make-opts) $(if $(filter um,$(ARCH)),,headers) all

.PHONY: clean
clean:
	$(Q)dh_clean
	$(Q)rm -rf debian/deb-env.vars* debian/*.files
	$(Q)$(MAKE) ARCH=$(ARCH) clean

# If DEB_HOST_ARCH is empty, it is likely that debian/rules was executed
# directly. Run 'dpkg-architecture --print-set --print-format=make' to
# generate a makefile construct that exports all DEB_* variables.
ifndef DEB_HOST_ARCH
include debian/deb-env.vars

debian/deb-env.vars:
	$(Q)dpkg-architecture -a$$(cat debian/arch) --print-set --print-format=make > $@.tmp
	$(Q)mv $@.tmp $@
endif