From: Yann E. MORIN Date: Mon, 28 Dec 2020 16:07:04 +0000 (+0100) Subject: support/download: add helper to generate a reproducible archive X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=cbe95b1a455bbefcaa90a08cf3dd1a590630921e;p=buildroot.git support/download: add helper to generate a reproducible archive 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 Cc: Thomas Petazzoni Cc: Vincent Fazio Acked-by: Arnout Vandecappelle (Essensium/Mind) Reviewed-by: Vincent Fazio ---8<------8<------8<------8<--- # 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 ---8<------8<------8<------8<--- --- diff --git a/support/download/helpers b/support/download/helpers new file mode 100755 index 0000000000..0e0432c884 --- /dev/null +++ b/support/download/helpers @@ -0,0 +1,70 @@ +# Generate a reproducible archive from the content of a directory +# +# $1 : input directory +# $2 : leading component in archive +# $3 : ISO8601 date: YYYY-MM-DDThh:mm:ssZZ +# $4 : output file +# $5... : globs of filenames to exclude from the archive, suitable for +# find's -path option, and relative to the input directory $1 +# +# Notes : +# - must not be called with CWD as, or below, the input directory +# - some temporary files are created in CWD, and removed at the end +# +# Example: +# $ find /path/to/temp/dir +# /path/to/temp/dir/ +# /path/to/temp/dir/some-file +# /path/to/temp/dir/some-dir/ +# /path/to/temp/dir/some-dir/some-other-file +# +# $ mk_tar_gz /path/to/some/dir \ +# foo_bar-1.2.3 \ +# 1970-01-01T00:00:00Z \ +# /path/to/foo.tar.gz \ +# '.git/*' '.svn/*' +# +# $ tar tzf /path/to/foo.tar.gz +# foo_bar-1.2.3/some-file +# foo_bar-1.2.3/some-dir/some-other-file +# +mk_tar_gz() { + local in_dir="${1}" + local base_dir="${2}" + local date="${3}" + local out="${4}" + shift 4 + local glob tmp pax_options + local -a find_opts + + for glob; do + find_opts+=( -or -path "./${glob#./}" ) + done + + pax_options="delete=atime,delete=ctime,delete=mtime" + pax_options+=",exthdr.name=%d/PaxHeaders/%f,exthdr.mtime={${date}}" + + tmp="$(mktemp --tmpdir="$(pwd)")" + pushd "${in_dir}" >/dev/null + + # Establish list + find . -not -type d -and -not \( -false "${find_opts[@]}" \) >"${tmp}.list" + # Sort list for reproducibility + LC_ALL=C sort <"${tmp}.list" >"${tmp}.sorted" + + # Create POSIX tarballs, since that's the format the most reproducible + tar cf - --transform="s#^\./#${base_dir}/#" \ + --numeric-owner --owner=0 --group=0 --mtime="${date}" \ + --format=posix --pax-option="${pax_options}" \ + -T "${tmp}.sorted" >"${tmp}.tar" + + # Compress the archive + gzip -6 -n <"${tmp}.tar" >"${out}" + + rm -f "${tmp}"{.list,.sorted,.tar} + + popd >/dev/null +} + +# Keep this line and the following as last lines in this file. +# vim: ft=bash