[systemd-devel] setting up to allow separate udev and systemd builds

[William Hubbs]

Hello Auke,

On Fri, Jun 15, 2012 at 04:26:36AM +0000, Kok, Auke-jan H wrote:
> On Fri, Jun 15, 2012 at 2:32 AM, William Hubbs <w.d.hubbs at gmail.com> wrote:
> > Hello Auke,
> >
> > I will answer your concerns as best as I can below.
> >
> > On Thu, Jun 14, 2012 at 03:35:09PM -0700, Kok, Auke-jan H wrote:
> >> 1) Timing. systemd+udevd just got merged.  We had a huge build system
> >> change. Let's not change it drastically again entirely now.
> >
> > From the point of view of a source based distro, the build system
> > as it currently stands is broken. Upstream supports running udev without
> > systemd, so why not building udev standalone as well, especially since
> > there is interest in doing the work?
> 
> It's not broken at all. What is broken is the assumption that one can just
> run `make install` willy nilly in a source distro and overwrite files in
> the live system.
> 
> This is a design problem in ALL source based distro's (including the one
> I worked on for years) and can't be fixed by upstream. Source distro's
> should really work on doing a proper `make DESTDIR= install` or use
> fakeroot/chroot installs and buffer the installation of files before the
> real rootfs is overwritten.
> 
> Not solving that is an error that the source distributions should solve,
> and definitely should not be the reason for an upstream project to jump
> to the aid of source distros.

As Wulf already pointed out, gentoo already does this properly, and we
also do our own sanity checks before we move the package to the live fs.

This is definitely not an issue we expect upstream projects to solve
 other than supporting DESTDIR, which udev and systemd already do.

> >> 4) Can be maintained out of tree for now: Nothing prevents gentoo from
> >> keeping this patch out of tree for their purposes.
> >
> >  Yes, we could, but what about exherbo, funtoo, linux from scratch and
> >  the other source based distros that may be out there?
> 
> they could pull the patch from gentoo's repository.

I suppose they could if they were comfortable doing that, but I tend to
agree with Wulf on this; I would rather not have custom patches being
shared between distros. Honestly I would rather have as few custom
patches as possible; custom patches can be a headache to maintain.

> I think this patch would be a lot more acceptable if you drop the split
> Makefile.am, remove the --disable-systemd option and just create an extra
> "make install-udev" target.
> 
> It would be a lot smaller too.

I could rework it so I don't split up the makefiles, sure, but let me
explain why the install-udev target does not solve the issue we are
trying to solve.

systemd has several more dependencies than udev. Because of that and
because of the way the build system is setup to only do a full systemd
build, I have to install all of systemd's dependencies on every gentoo
user's system regardless of whether or not they are using systemd or
udev standalone.

What I need is a way to tell the configure script and Makefiles that I
am only interested in building udev and not a full systemd build.

There was another patch that came from the linux from scratch community
posted on the linux-hotplug list [1].

I spoke with Kay about that patch, and he didn't sound like he liked it
too much.

William

[1] http://www.spinics.net/lists/hotplug/msg05529.html
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