dependencies: some improvements

As far as I'm concerned, this should be the last version of this patch series. I think it is clean and complete and has received the necessary review.

---
v4: add Acks by ThomasP and update after feedback
v5: add extra patch to fix download problem because dl dir is absent
v6: use $(@D) and line up with latest git

As suggested by Arnout Vandecappelle, move toolchain/dependencies to support/dependencies, as it really is not toolchain-specific anymore.

---
 Makefile                               |    2 ++
 toolchain/dependencies/dependencies.mk |    2 +-
 toolchain/dependencies/dependencies.sh |  Bin
 toolchain/toolchain-buildroot.mk       |    1 -
 toolchain/toolchain-crosstool-ng.mk    |    1 -
 toolchain/toolchain-external.mk        |    1 -
 6 files changed, 3 insertions(+), 4 deletions(-)

@@ -297,6 +297,8 @@ include package/Makefile.in
 
 all: world
 
+include support/dependencies/dependencies.mk
+
 # We also need the various per-package makefiles, which also add
 # each selected package to TARGETS if that package was selected
 # in the .config file.

rename from toolchain/dependencies/dependencies.mk
rename to support/dependencies/dependencies.mk
@@ -14,7 +14,7 @@ core-dependencies:
 	@HOSTCC="$(firstword $(HOSTCC))" MAKE="$(MAKE)" \
 		CONFIG_FILE="$(CONFIG_DIR)/.config" \
 		DL_TOOLS="$(sort $(DL_TOOLS_DEPENDENCIES))" \
-		$(TOPDIR)/toolchain/dependencies/dependencies.sh
+		$(TOPDIR)/support/dependencies/dependencies.sh
 
 dependencies: core-dependencies $(DEPENDENCIES_HOST_PREREQ)
 

rename from toolchain/dependencies/dependencies.sh
rename to support/dependencies/dependencies.sh

@@ -1,6 +1,5 @@
 # Include files required for the internal toolchain backend
 
-include toolchain/dependencies/dependencies.mk
 include toolchain/elf2flt/elf2flt.mk
 include toolchain/gcc/gcc-uclibc-4.x.mk
 include toolchain/gdb/gdb.mk

@@ -2,7 +2,6 @@
 
 # Explicit ordering:
 include toolchain/helpers.mk
-include toolchain/dependencies/dependencies.mk
 include toolchain/elf2flt/elf2flt.mk
 include toolchain/gcc/gcc-uclibc-4.x.mk
 include toolchain/gdb/gdb.mk

@@ -1,7 +1,6 @@
 # Required includes for the external toolchain backend
 
 include toolchain/helpers.mk
-include toolchain/dependencies/dependencies.mk
 include toolchain/elf2flt/elf2flt.mk
 include toolchain/gcc/gcc-uclibc-4.x.mk
 include toolchain/gdb/gdb.mk

Thomas> As suggested by Arnout Vandecappelle, move toolchain/dependencies to Thomas> support/dependencies, as it really is not toolchain-specific anymore.

Committed, thanks.

Bye, Peter Korsgaard

Although support/dependencies/dependencies.sh checks for the version of make, this script doesn't get a chance to run if make encounters a syntax error as a result of being too old.

For example, the following syntax is only supported from make 3.81 onwards:

ifeq ($(BR2_TOOLCHAIN_BUILDROOT),y)
include toolchain/toolchain-buildroot.mk
else ifeq ($(BR2_TOOLCHAIN_EXTERNAL),y)
include toolchain/toolchain-external.mk
else ifeq ($(BR2_TOOLCHAIN_CTNG),y)
include toolchain/toolchain-crosstool-ng.mk
endif

This patch adds a check for the version of make very early in the Makefile, so that old make versions are handled gracefully.

---
 Makefile |  6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

@@ -26,6 +26,12 @@
 # Set and export the version string
 export BR2_VERSION:=2012.02-git
 
+# Check for minimal make version (note: this check will break at make 10.x)
+MIN_MAKE_VERSION=3.81
+ifeq (,$(filter $(MIN_MAKE_VERSION),$(firstword $(sort $(MAKE_VERSION) $(MIN_MAKE_VERSION)))))
+$(error You have make '$(MAKE_VERSION)' installed. GNU make >= $(MIN_MAKE_VERSION) is required)
+endif
+
 # This top-level Makefile can *not* be executed in parallel
 .NOTPARALLEL:
 

Thomas> Although support/dependencies/dependencies.sh checks for the Thomas> version of make, this script doesn't get a chance to run if Thomas> make encounters a syntax error as a result of being too old.

Thomas> export BR2_VERSION:=2012.02-git

Thomas> +# Check for minimal make version (note: this check will break Thomas> at make 10.x)

Thomas> +MIN_MAKE_VERSION=3.81
Thomas> +ifeq (,$(filter $(MIN_MAKE_VERSION),$(firstword $(sort $(MAKE_VERSION) $(MIN_MAKE_VERSION)))))

It seems simpler to just compare with MAKE_VERSION, so I changed it to be:

ifeq ($(firstword $(sort $(MAKE_VERSION) $(MIN_MAKE_VERSION))),$(MAKE_VERSION))

Committed, thanks.

Bye, Peter Korsgaard

Peter> It seems simpler to just compare with MAKE_VERSION, so I changed it to Peter> be:

Peter> ifeq ($(firstword $(sort $(MAKE_VERSION) $(MIN_MAKE_VERSION))),$(MAKE_VERSION))

Ehh, swap that:

ifneq ($(firstword $(sort $(MAKE_VERSION) $(MIN_MAKE_VERSION))),$(MIN_MAKE_VERSION))

Otherwise it would fail for 3.81.

Bye, Peter Korsgaard

Sometimes, buildroot needs a certain host tool to do its job, e.g. tar. In many cases, we expect this tool to be present on the host system, but this is not always the case. Or maybe, the version on the host system is not suitable, and we need a more recent one.

In some of these cases, instead of bailing out, buildroot could build the package first (but only if the existing system package is not suitable).

To aid in detecting if a host package is suitable or not, this patch adds a function suitable-host-package. When called with parameter foo, it will execute check-host-foo.sh. This script should return either the path to the suitable host package, or the empty string if no suitable package can be found. The rules to determine whether something is suitable or not is left to check-host-foo.sh and depends on foo.

An example usage of suitable-host-package is:
DEPENDENCIES_HOST_PREREQ += $(if $(call suitable-host-package,foo),,host-foo)

To avoid cluttering the existing dependencies.mk file, it includes any check-host-foo.mk file. These files can be used to hold appropriate dependency-related actions for foo.

v1 Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <[email protected]>

---
v3: Add optional second parameter to suitable-host-package, to specify a
candidate tool.

 support/dependencies/dependencies.mk |  10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

@@ -6,6 +6,16 @@
 ######################################################################
 
 DEPENDENCIES_HOST_PREREQ:=
+
+# suitable-host-pkg: calls check-host-$(1).sh shell script. Parameter (2)
+# can be the candidate to be checked. If not present, the check-host-$(1).sh
+# script should use 'which' to find a candidate. The script should return
+# the path to the suitable host tool, or nothing if no suitable tool was found.
+define suitable-host-package
+$(shell support/dependencies/check-host-$(1).sh $(2))
+endef
+-include support/dependencies/check-host-*.mk
+
 ifeq ($(BR2_STRIP_sstrip),y)
 DEPENDENCIES_HOST_PREREQ+=host-sstrip
 endif

Thomas> Sometimes, buildroot needs a certain host tool to do its job, Thomas> e.g. tar. In many cases, we expect this tool to be present on Thomas> the host system, but this is

Committed, thanks.

Bye, Peter Korsgaard

If during the dependencies step, a package needs to be downloaded, the download directory already has to be present. If not, the file will be downloaded under the name 'dl' instead of in the directory 'dl'.

This patch changes the order of dirs and dependencies in the world target to fix this.

---
 Makefile |  2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

@@ -375,7 +375,7 @@ dirs: $(DL_DIR) $(TOOLCHAIN_DIR) $(BUILD
 
 prepare: $(BUILD_DIR)/buildroot-config/auto.conf
 
-world: prepare dependencies dirs $(BASE_TARGETS) $(TARGETS_ALL)
+world: prepare dirs dependencies $(BASE_TARGETS) $(TARGETS_ALL)
 
 $(O)/toolchainfile.cmake:
 	@echo -en "\

Thomas> If during the dependencies step, a package needs to be downloaded, the Thomas> download directory already has to be present. If not, the file will be Thomas> downloaded under the name 'dl' instead of in the directory 'dl'.

Thomas> This patch changes the order of dirs and dependencies in the Thomas> world target to fix this.

Committed, thanks.

Bye, Peter Korsgaard

Some toolchains, like the one built with buildroot itself, use hardlinks (for example to link between the c++ and g++ binary). Unpacking such a toolchain with the --strip-components options does not work correctly if the system tar is too old (<1.17). Even recent releases of RedHat/CentOS still ship with tar 1.15.

This patch checks for a suitable tar version (tar 1.17+) on the host system, and adds host-tar to the host dependencies if none can be found.

host-tar is download and extracted as cpio.gz instead of tar.gz, to prevent chicken-egg problem.

v4 Acked-by: Arnout Vandecappelle (Essensium/Mind) <[email protected]>

---
v3: remove chicken-egg problem, causing great simplification; update check-
host-tar.sh with Arnout's comments.
v4: use 'define' for HOST_TAR_EXTRACT_CMDS after suggestion by ThomasP
v6: use $(@D) instead of HOST_TAR_DIR, suggestion from Arnout. Additionally,
I needed to set HOST_TAR_DEPENDENCIES to nothing, after the automatic derivation of HOST_ dependencies.

 package/Makefile.package.in            |  12 ------------
 package/tar/tar.mk                     |  13 +++++++++++++
 support/dependencies/check-host-tar.mk |   9 +++++++++
 support/dependencies/check-host-tar.sh |  35 +++++++++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+), 12 deletions(-)

@@ -299,18 +299,6 @@ define DOWNLOAD
 	exit 1
 endef
 
-# Utility programs used to build packages
-TAR ?= tar
-
-# Automatically detect tar --strip-path/components option
-TAR_STRIP_COMPONENTS := \
-  $(shell $(TAR) --help | grep strip-path > /dev/null ; \
-  if test $$? = 0 ; then \
-   echo '--strip-path' ; \
-  else \
-   echo '--strip-components' ; \
-  fi)
-
 # Needed for the foreach loops to loop over the list of hooks, so that
 # each hook call is properly separated by a newline.
 define sep

@@ -10,6 +10,19 @@ TAR_SITE = $(BR2_GNU_MIRROR)/tar
 # Prefer full-blown tar over buybox's version
 ifeq ($(BR2_PACKAGE_BUSYBOX),y)
 TAR_DEPENDENCIES += busybox
+HOST_TAR_DEPENDENCIES =
 endif
 
 $(eval $(call AUTOTARGETS))
+
+# host-tar: use cpio.gz instead of tar.gz to prevent chicken-egg problem
+# of needing tar to build tar.
+HOST_TAR_SOURCE = tar-$(TAR_VERSION).cpio.gz
+define HOST_TAR_EXTRACT_CMDS
+	mkdir -p $(@D)
+	cd $(@D) && \
+		$(INFLATE.gz) $(DL_DIR)/$(HOST_TAR_SOURCE) | cpio -i
+	mv $(@D)/tar-$(TAR_VERSION)/* $(@D)
+	rmdir $(@D)/tar-$(TAR_VERSION)
+endef
+$(eval $(call AUTOTARGETS,host))

new file mode 100644
@@ -0,0 +1,9 @@
+TAR ?= tar
+
+ifeq (,$(call suitable-host-package,tar,$(TAR)))
+  DEPENDENCIES_HOST_PREREQ += host-tar
+  TAR = $(HOST_DIR)/usr/bin/tar
+endif
+
+# Since TAR is at least 1.17, it will certainly support --strip-components
+TAR_STRIP_COMPONENTS = --strip-components

new file mode 100755
@@ -0,0 +1,35 @@
+#!/bin/sh
+
+candidate="$1"
+
+tar=`which $candidate`
+if [ ! -x "$tar" ]; then
+	tar=`which tar`
+	if [ ! -x "$tar" ]; then
+		# echo nothing: no suitable tar found
+		exit 1
+	fi
+fi
+
+# Output of 'tar --version' examples:
+# tar (GNU tar) 1.15.1
+# tar (GNU tar) 1.25
+version=`$tar --version | head -n 1 | sed 's/^.*\s\([0-9]\+\.\S\+\).*$/\1/'`
+major=`echo "$version" | cut -d. -f1`
+minor=`echo "$version" | cut -d. -f2`
+bugfix=`echo "$version" | cut -d. -f3`
+
+# Minimal version = 1.17 (previous versions do not correctly unpack archives
+# containing hard-links if the --strip-components option is used).
+major_min=1
+minor_min=17
+if [ $major -gt $major_min ]; then
+	echo $tar
+else
+	if [ $major -eq $major_min -a $minor -ge $minor_min ]; then
+		echo $tar
+	else
+		# echo nothing: no suitable tar found
+		exit 1
+	fi
+fi

Thomas> Some toolchains, like the one built with buildroot itself, use Thomas> hardlinks (for example to link between the c++ and g++ Thomas> binary). Unpacking such a toolchain with the --strip-components Thomas> options does not work correctly if the system tar is too old Thomas> (<1.17). Even recent releases of RedHat/CentOS still ship with Thomas> tar 1.15.

Committed, thanks.

Bye, Peter Korsgaard