On Mon, Feb 01, 2016 at 07:41:59AM -0800, Josh Triplett wrote:
> On Mon, Feb 01, 2016 at 04:24:21PM +0100, Ondřej Surý wrote:
> > Hi Michael,
> >
> > I never bothered to implement more than 'd', but I am happy to
> > contribute my sysvrc shell snippet I use as replacement for systems
> > without systemd-tmpfiles installed.
> >
> > ```
> > do_tmpfiles() {
> > local type path mode user group age argument
> > if [ -r "$1" ]; then
> > if [ -x /bin/systemd-tmpfiles ]; then
> > /bin/systemd-tmpfiles --create "$1"
> > else
> > while read type path mode user group age argument; do
> > case "$type" in
> > d)
> > mkdir -p "$path";
> > chmod "$mode" "$path";
> > chown "$user:$group" "$path";
> > ;;
> > \#*)
> > ;;
> > *)
> > log_warning_msg "tmpfile.d type '$type' is not
> > supported yet"
> > ;;
> > esac
> > done < "$1"
> > fi
> > else
> > log_warning_msg "tmpfiles.d file '$1' doesn't exist or is not
> > readable"
> > fi
> > }
> > ```
> >
> > It should be fairly easy to implement the most common stuff used in
> > Debian.
>
> Implementing the various operation letters makes up half the problem.
> The other half involves handling the various tmpfiles.d directories and
> the precedence between them. That includes the usual "override files
> with the same filename" mechanism, but also:
>
> > All configuration files are sorted by their filename in lexicographic
> > order, regardless of which of the directories they reside in. If
> > multiple files specify the same path, the entry in the file with the
> > lexicographically earliest name will be applied. All other conflicting
> > entries will be logged as errors. When two lines are prefix and suffix
> > of each other, then the prefix is always processed first, the suffix
> > later. Lines that take globs are applied after those accepting no
> > globs. If multiple operations shall be applied on the same file, (such
> > as ACL, xattr, file attribute adjustments), these are always done in
> > the same fixed order. Otherwise, the files/directories are processed
> > in the order they are listed.
>
> That logic seems relatively straightforward (though fiddly) to implement
> in a language with associative arrays, such as bash or Python, but not
> in a language without them, such as POSIX sh.
Also, "Fields may be enclosed within quotes and contain C-style
escapes.". And fields can contain a few substitution fields. See "man
tmpfiles.d".
