We currently need to generate reproducible archives in at least two
locations: the git and svn download backends. We also know of some
future potential use (e.g. the other download backends, like cvs, or
in the upcoming download post-processors for vendoring, like cargo
and go).
However, we are currently limited to a narrow range of tar versions
that we support, to create reproducible archives, because the gnu
format we use has changed with tar 1.30.
As a consequence, and as time advances, more and more distros are,
or will eventually start, shipping with tar 1.30 or later, and thus
we need to always build our on host-tar.
Now, thanks to some grunt work by Vincent, we have a set of options
that we can pass tar, to generate reproducible archives back from
tar-1.27 and up through tar-1.32, the latest released version.
However, those options are non-trivial, so we do not want to have
to repeat those (and maintain them) in multiple locations.
Introduce a helper that can generate a reproducible archive from
an input directory.
The --pax-option, to set specific PAX headers, does not accept
RFC2822 timestamps which value are too away from some fixed point
(set atcompile-time?):
tar: Time stamp is out of allowed range
However, the same timestamps passed as strict compliant ISO 8601 are
accepted, so that's what we expect as a date format.
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Vincent Fazio <vfazio@xes-inc.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Reviewed-by: Vincent Fazio <vfazio@xes-inc.com>
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# Here is a Makefile used to test all the versions of tar, with
# different output formats and different sets of options:
# Versions prior to 1.27 do not build on recent machines, because
# 'gets()' got removed (rightfully so), so don't count them as
# candidates.
VERSIONS = 1.27 1.27.1 1.28 1.29 1.30 1.31 1.32
DATE = Thu 21 May 2020 06:44:11 PM CEST
TARS = \
$(patsubst %,test_gnu_%.tar,$(VERSIONS)) \
$(patsubst %,test_posix_%.tar,$(VERSIONS)) \
$(patsubst %,test_posix_paxoption_%.tar,$(VERSIONS))
all: $(TARS)
sha1sum $(^)
.INTERMEDIATE: test_%.tar
test_gnu_%.tar: tar.% list
./$(<) cf - -C test \
--transform="s#^\./#test-version/#" \
--numeric-owner --owner=0 --group=0 \
--mtime="$(DATE)" \
--format=gnu \
-T list \
>$(@)
test_posix_%.tar: tar.% list
./$(<) cf - -C test \
--transform="s#^\./#test-version/#" \
--numeric-owner --owner=0 --group=0 \
--mtime="$(DATE)" \
--format=posix \
-T list \
>$(@)
test_posix_paxoption_%.tar: tar.% list
./$(<) cf - -C test \
--transform="s#^\./#test-version/#" \
--numeric-owner --owner=0 --group=0 \
--mtime="$(DATE)" \
--format=posix \
--pax-option='delete=atime,delete=ctime,delete=mtime' \
--pax-option='exthdr.name=%d/PaxHeaders/%f,exthdr.mtime={$(DATE)}' \
-T list \
>$(@)
list: .FORCE
list: test
(cd test && find . -not -type d ) |LC_ALL=C sort >$(@)
LONG = L$$(for i in $$(seq 1 200); do printf 'o'; done)ng
test: .FORCE
test:
rm -rf test
mkdir -p test/bar
echo foo >test/Foo
echo bar >test/bar/Bar
ln -s bar/Bar test/buz
echo long >test/Very-$(LONG)-filename
ln test/Very-$(LONG)-filename \
test/short
.PRECIOUS: tar.%
tar.%: tar-%
cd $(<) && ./configure
$(MAKE) -C $(<)
install -m 0755 $(<)/src/tar $(@)
.PRECIOUS: tar-%
tar-%: tar-%.tar.gz
tar xzf $(<)
.PRECIOUS: tar-%.tar.gz
tar-%.tar.gz:
wget "https://ftp.gnu.org/gnu/tar/$(@)"
.FORCE:
clean:
rm -rf tar-* tar.* test_* test list
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