[Buildroot] [PATCH 3/6] infra: fix 'packages-file-list.txt' with TLP

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello,

Adding Gustavo in Cc. Gustavo, you are working on TLP support. Could
you comment on the below patch?

See also my comments below.

On Mon, 14 Nov 2016 14:22:35 +0100, J?r?me Pouiller wrote:
> Until now, `$(BUILD_DIR)/packages-file-list.txt' was not filled properly when
> top level parallelization is enabled. Therefore, all scripts that rely on
> packages-file-list.txt did not work.
> 
> In order to fix it,this patch place target installation task in a critical
> section.
> 
> Signed-off-by: J?r?me Pouiller <jezz@sysmic.org>
> ---
>  package/pkg-generic.mk | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/package/pkg-generic.mk b/package/pkg-generic.mk
> index 987efa6..c5f70e0 100644
> --- a/package/pkg-generic.mk
> +++ b/package/pkg-generic.mk
> @@ -62,6 +62,9 @@ GLOBAL_INSTRUMENTATION_HOOKS += step_time
>  # files currently installed in the target. Note that the MD5 is also
>  # stored, in order to identify if the files are overwritten.
>  define step_pkg_size_start
> +	while ! flock $(BUILD_DIR) -c "[ ! -e $(BUILD_DIR)/.target_lock ] && touch $(BUILD_DIR)/.target_lock"; do \
> +		sleep 0.5; \
> +	done

I personally don't really like this retry loop around flock, but since
package-file-list.txt is a global file, I don't really see how to do
otherwise. Unless storing a per-package file with just the time/date of
the start/end of each step for this package, and then have a
post-processing logic at the very end of the build that regroups all
those per-package files into a single global file, ordering the entries
by their timestamp. Don't know if it's really better.


>  	(cd $(TARGET_DIR) ; find . -type f -print0 | xargs -0 md5sum) | sort > \
>  		$($(PKG)_DIR)/.br_filelist_before
>  endef
> @@ -78,6 +81,7 @@ define step_pkg_size_end
>  		while read hash file ; do \
>  			echo "$(1),$${file}" >> $(BUILD_DIR)/packages-file-list.txt ; \
>  		done
> +	rm $(BUILD_DIR)/.target_lock
>  endef
>  
>  define step_pkg_size

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com