Re: [PATCH] Allow disabling the build of all of systemd, leaving just udev

[Bruce Dubbs <bruce.dubbs@gmail.com>]

William Hubbs wrote:

> This is where I want to go once we have the Makefile broken up. This
> will also require some work in configure.ac, but I think it will be
> worth that because it will give packagers the flexability to build what
> they want.
> 
> include Makefile-shared.am
> if ENABLE_UDEV
> include Makefile-udev.am
> endif
> if ENABLE_TOOLS
> include Makefile-tools.am
> endif
> if ENABLE_SYSTEMD
> include Makefile-systemd.am
> endif

With this type of setup, ENABLE_SYSTEMD must imply ENABLE_TOOLS and 
ENABLE_UDEV.

> The first stage of this will be breaking up Makefile.am and using
> includes without condissionals. Once everything builds cleanly in that
> setup, we can  do the work in configure.ac and add condissionals to
> Makefile.am.

The first thing that will have to be done is to break up 
libsystemd_shared_la_SOURCES in Makefile.am.  That definition combines 
files incompatible with udev-only with files required by udev.  udev needs:

log
label
mkdir
cgroup-util
strv
path-util
conf-files
hashmap
set
exit-status
util
dev-setup

but does not need:

cgroup-show
conf-parser
hwclock
pager
ratelimit
socket-util
spawn-ask-password-agent
spawn-polkit-agent
specifier
utf8
virt
watchdog

Basically all of the above are combined into libsystemd-core.la and that 
needs to be split into two.  I'd just split the first group into 
libudev-core.la.

To link, udev also needs the file in libsystemd_daemon_la_SOURCES 
(sd-daumon) for udevd, but that probably could be removed with some 
appropriate ifdefs in udevd.c.

   -- Bruce