kumquat-buildroot/fs/common.mk
Thomas De Schampheleire 54456cc698 infra: consistently use double dollar signs inside inner-xxx-targets
The inner-xxx-targets in the buildroot package infrastructures are
evaluated using $(eval) which causes variable references to be a bit
different than in regular make code. As we want most references to be
expanded only at the time of the $(eval) we should not use standard
references $(VAR) but rather use double dollar signs $$(VAR). This includes
function references like $(call), $(subst), etc. The only exception is the
reference to pkgdir/pkgname and numbered variables, which are parameters to
the inner block: $(1), $(2), etc.

This patch introduces consistent usage of double-dollar signs throughout the
different inner-xxx-targets blocks.

In some cases, this would potentially cause circular references, in
particular when the value of HOST_FOO_VAR would be obtained from the
corresponding FOO_VAR if HOST_FOO_VAR is not defined. In these cases, a test
is added to check for a host package (the only case where such constructions
are relevant; these are not circular).

Benefits of these changes are:
- behavior of variables is now again as expected. For example, setting
  $(2)_VERSION = virtual in pkg-virtual.mk will effectively work, while
  originally it would cause very odd results.

- The output of 'make printvars' is now much more useful. This target shows
  the value of all variables, and the expression that led to that value.
  However, if the expression was coming from an inner-xxx-targets block, and
  was using single dollar signs, it would show in printvars as
    VAR = value (value)
  while if double dollar signs are used, it would effectively look like
    VAR = value (actual expression)
  as is intended.
  This improvement is for example effective for FOO_DL_VERSION, FOO_RAWNAME,
  FOO_SITE_METHOD and FOO_MAKE.

The correctness of this patch has been verified using 'make printvars',
'make manual' and 'make legal-info' before and after applying this patch,
and comparing the output.

Insight-provided-by: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2014-06-14 19:09:54 +02:00

113 lines
4.2 KiB
Makefile

#
# Macro that builds the needed Makefile target to create a root
# filesystem image.
#
# The following variable must be defined before calling this macro
#
# ROOTFS_$(FSTYPE)_CMD, the command that generates the root
# filesystem image. A single command is allowed. The filename of the
# filesystem image that it must generate is $$@.
#
# The following variables can optionaly be defined
#
# ROOTFS_$(FSTYPE)_DEPENDENCIES, the list of dependencies needed to
# build the root filesystem (usually host tools)
#
# ROOTFS_$(FSTYPE)_PRE_GEN_HOOKS, a list of hooks to call before
# generating the filesystem image
#
# ROOTFS_$(FSTYPE)_POST_TARGETS, the list of targets that should be
# run after running the main filesystem target. This is useful for
# initramfs, to rebuild the kernel once the initramfs is generated.
#
# In terms of configuration option, this macro assumes that the
# BR2_TARGET_ROOTFS_$(FSTYPE) config option allows to enable/disable
# the generation of a filesystem image of a particular type. If
# configura options BR2_TARGET_ROOTFS_$(FSTYPE)_GZIP,
# BR2_TARGET_ROOTFS_$(FSTYPE)_BZIP2 or
# BR2_TARGET_ROOTFS_$(FSTYPE)_LZMA exist and are enabled, then the
# macro will automatically generate a compressed filesystem image.
FAKEROOT_SCRIPT = $(BUILD_DIR)/_fakeroot.fs
FULL_DEVICE_TABLE = $(BUILD_DIR)/_device_table.txt
ROOTFS_DEVICE_TABLES = $(call qstrip,$(BR2_ROOTFS_DEVICE_TABLE) \
$(BR2_ROOTFS_STATIC_DEVICE_TABLE))
USERS_TABLE = $(BUILD_DIR)/_users_table.txt
ROOTFS_USERS_TABLES = $(call qstrip,$(BR2_ROOTFS_USERS_TABLES))
# Since this function will be called from within an $(eval ...)
# all variable references except the arguments must be $$-quoted.
define ROOTFS_TARGET_INTERNAL
# extra deps
ROOTFS_$(2)_DEPENDENCIES += host-fakeroot host-makedevs \
$$(if $$(PACKAGES_USERS),host-mkpasswd)
ifeq ($$(BR2_TARGET_ROOTFS_$(2)_GZIP),y)
ROOTFS_$(2)_COMPRESS_EXT = .gz
ROOTFS_$(2)_COMPRESS_CMD = gzip -9 -c
endif
ifeq ($$(BR2_TARGET_ROOTFS_$(2)_BZIP2),y)
ROOTFS_$(2)_COMPRESS_EXT = .bz2
ROOTFS_$(2)_COMPRESS_CMD = bzip2 -9 -c
endif
ifeq ($$(BR2_TARGET_ROOTFS_$(2)_LZMA),y)
ROOTFS_$(2)_DEPENDENCIES += host-lzma
ROOTFS_$(2)_COMPRESS_EXT = .lzma
ROOTFS_$(2)_COMPRESS_CMD = $$(LZMA) -9 -c
endif
ifeq ($$(BR2_TARGET_ROOTFS_$(2)_LZO),y)
ROOTFS_$(2)_DEPENDENCIES += host-lzop
ROOTFS_$(2)_COMPRESS_EXT = .lzo
ROOTFS_$(2)_COMPRESS_CMD = $$(LZOP) -9 -c
endif
ifeq ($$(BR2_TARGET_ROOTFS_$(2)_XZ),y)
ROOTFS_$(2)_COMPRESS_EXT = .xz
ROOTFS_$(2)_COMPRESS_CMD = xz -9 -C crc32 -c
endif
$$(BINARIES_DIR)/rootfs.$(1): target-finalize $$(ROOTFS_$(2)_DEPENDENCIES)
@$$(call MESSAGE,"Generating root filesystem image rootfs.$(1)")
$$(foreach hook,$$(ROOTFS_$(2)_PRE_GEN_HOOKS),$$(call $$(hook))$$(sep))
rm -f $$(FAKEROOT_SCRIPT)
rm -f $$(TARGET_DIR_WARNING_FILE)
rm -f $$(USERS_TABLE)
echo "chown -h -R 0:0 $$(TARGET_DIR)" >> $$(FAKEROOT_SCRIPT)
ifneq ($$(ROOTFS_DEVICE_TABLES),)
cat $$(ROOTFS_DEVICE_TABLES) > $$(FULL_DEVICE_TABLE)
ifeq ($$(BR2_ROOTFS_DEVICE_CREATION_STATIC),y)
printf '$$(subst $$(sep),\n,$$(PACKAGES_DEVICES_TABLE))' >> $$(FULL_DEVICE_TABLE)
endif
printf '$$(subst $$(sep),\n,$$(PACKAGES_PERMISSIONS_TABLE))' >> $$(FULL_DEVICE_TABLE)
echo "$$(HOST_DIR)/usr/bin/makedevs -d $$(FULL_DEVICE_TABLE) $$(TARGET_DIR)" >> $$(FAKEROOT_SCRIPT)
endif
ifneq ($$(ROOTFS_USERS_TABLES),)
cat $$(ROOTFS_USERS_TABLES) >> $$(USERS_TABLE)
endif
printf '$$(subst $$(sep),\n,$$(PACKAGES_USERS))' >> $$(USERS_TABLE)
PATH=$$(BR_PATH) $$(TOPDIR)/support/scripts/mkusers $$(USERS_TABLE) $$(TARGET_DIR) >> $$(FAKEROOT_SCRIPT)
echo "$$(ROOTFS_$(2)_CMD)" >> $$(FAKEROOT_SCRIPT)
chmod a+x $$(FAKEROOT_SCRIPT)
PATH=$$(BR_PATH) $$(HOST_DIR)/usr/bin/fakeroot -- $$(FAKEROOT_SCRIPT)
$$(INSTALL) -m 0644 support/misc/target-dir-warning.txt $$(TARGET_DIR_WARNING_FILE)
-@rm -f $$(FAKEROOT_SCRIPT) $$(FULL_DEVICE_TABLE)
ifneq ($$(ROOTFS_$(2)_COMPRESS_CMD),)
PATH=$$(BR_PATH) $$(ROOTFS_$(2)_COMPRESS_CMD) $$@ > $$@$$(ROOTFS_$(2)_COMPRESS_EXT)
endif
rootfs-$(1)-show-depends:
@echo $$(ROOTFS_$(2)_DEPENDENCIES)
rootfs-$(1): $$(BINARIES_DIR)/rootfs.$(1) $$(ROOTFS_$(2)_POST_TARGETS)
ifeq ($$(BR2_TARGET_ROOTFS_$(2)),y)
TARGETS_ROOTFS += rootfs-$(1)
endif
endef
define ROOTFS_TARGET
$(call ROOTFS_TARGET_INTERNAL,$(1),$(call UPPERCASE,$(1)))
endef
include $(sort $(wildcard fs/*/*.mk))