Re: [OE-core] [PATCH 4/6] reproducible_build: clamp the rootfs tarball mtime to the epoch

["Jate Sujjavanich" <jatedev@gmail.com>]

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I have started using the following code to set the mtimes of files written
after the build timestamp. It assumes that SOURCE_DATE_EPOCH of packages
are never in the future.

# Set to empty to allow custom function below to run
REPRODUCIBLE_TIMESTAMP_ROOTFS ?= ""

# Use DATETIME of build as SOURCE_DATE_EPOCH for image
export SOURCE_DATE_EPOCH = "${@int( time.mktime( time.strptime('${DATETIME}',
'%Y%m%d%H%M%S') ) ) }"

reproducible_final_image_task () {
if [ "${BUILD_REPRODUCIBLE_BINARIES}" = "1" ]; then
if [ "$REPRODUCIBLE_TIMESTAMP_ROOTFS" = "" ]; then
# Use commit time of tuxzilla root in usual Syntux build
REPRODUCIBLE_TIMESTAMP_ROOTFS=`git -C "${COREBASE}/../" log -1 --pretty=%ct
2>/dev/null`
if [ "$REPRODUCIBLE_TIMESTAMP_ROOTFS" = "" ]; then
REPRODUCIBLE_TIMESTAMP_ROOTFS=`stat -c%Y ${@bb.utils.which(d.getVar("BBPATH"),
"conf/bitbake.conf")}`
fi
fi
# Set mtime of all files to a reproducible value
bbnote "reproducible_final_image_task: mtime set to
$REPRODUCIBLE_TIMESTAMP_ROOTFS"
# Files with mtime after build stamp should be part of rootfs creation
DAYS_SINCE_BUILD=`python3 -c "import time; print((time.time() -
${SOURCE_DATE_EPOCH}) / 86400)"`
find ${IMAGE_ROOTFS} -mtime -$DAYS_SINCE_BUILD -exec touch -h --date=@
$REPRODUCIBLE_TIMESTAMP_ROOTFS {} \;
fi
}


On Tue, Dec 1, 2020 at 12:16 PM Ross Burton <ross@burtonini.com> wrote:

> On Tue, 1 Dec 2020 at 15:45, Richard Purdie
> <richard.purdie@linuxfoundation.org> wrote:
> > I'm not convinced this is correct as it could mess up the timestamps of
> > stamps set in other recipes?
> >
> > It's also tar specific and should really be across all image types?
>
> Yes, it most likely should be done at rootfs time instead.
>
> Ross
>
> 
>
>

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