kumquat-buildroot/package/systemd/fakeroot_tmpfiles.sh
Norbert Lange 0d9b84b7a8 package/systemd: invoke systemd-tmpfilesd on final image
Especially for read-only filesystems it is helpful to
pre-create all folders for non-volatile paths.

This needs to run under fakeroot to allow setting
uids/gids/perms for the target fs.

systemd-tmpfilesd supports specifiers and target rootfs,
but some specifiers resolve to information from the host,
it is necessary to specially handle (skip) entries that
contain problematic specifiers.

Signed-off-by: Norbert Lange <nolange79@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
2022-01-09 15:09:39 +01:00

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#!/bin/sh
#
# The systemd-tmpfiles has the ability to grab information
# from the filesystem (instead from the running system).
#
# tmpfs directories (/tmp, /proc, ...) are skipped since they're not
# relevant for the rootfs image.
#
# However there are a few specifiers that *always* will grab
# information from the running system examples are %a, %b, %m, %H
# (Architecture, Boot UUID, Machine UUID, Hostname).
#
# See [1] for historic information.
#
# This script will (conservatively) skip tmpfiles lines that have
# such an specifier to prevent leaking host information.
#
# shell expansion is critical to be POSIX compliant,
# this script wont work with zsh in its default mode for example.
#
# The script takes several measures to handle more complex stuff
# like passing this correctly:
# f+ "/var/example" - - - - %B\n%o\n%w\n%W%%\n
#
# [1] - https://github.com/systemd/systemd/pull/16187
[ -n "${HOST_SYSTEMD_TMPFILES-}" ] ||
HOST_SYSTEMD_TMPFILES=systemd-tmpfiles
[ -n "${1-}" -a -d "${1-}"/usr/lib/tmpfiles.d ] ||
{ echo 1>&2 "$0: need ROOTFS argument"; exit 1; }
${HOST_SYSTEMD_TMPFILES} --no-pager --cat-config --root="$1" |
sed -e '/^[[:space:]]*#/d' -e 's,^[[:space:]]*,,' -e '/^$/d' |
while read -r line; do
# it is allowed to use quotes around arguments,
# so let the shell pack the arguments
eval "set -- $line"
# dont output warnings for directories we dont process
[ "${2#/dev}" = "${2}" ] && [ "${2#/proc}" = "${2}" ] &&
[ "${2#/run}" = "${2}" ] && [ "${2#/sys}" = "${2}" ] &&
[ "${2#/tmp}" = "${2}" ] && [ "${2#/mnt}" = "${2}" ] ||
continue
# blank out all specs that are ok to use,
# test if some remain. (Specs up to date with v250)
if echo "$2 ${7-}" | sed -e 's,%[%BCEgGhLMosStTuUVwW],,g' | grep -v -q '%'; then
# no "bad" specifiers, pass the line unmodified
eval "printf '%s\n' '$line'"
else
# warn
eval "printf 'ignored spec: %s\n' '$line' 1>&2"
fi
done |
TMPDIR= TEMP= TMP= ${HOST_SYSTEMD_TMPFILES} --create --boot --root="$1" \
--exclude-prefix=/dev --exclude-prefix=/proc --exclude-prefix=/run \
--exclude-prefix=/sys --exclude-prefix=/tmp --exclude-prefix=/mnt \
-