[Pkg-sysvinit-devel] Bug#623174: Bug#621803: Add support for /run directory

[rleigh]

On Tue, Apr 26, 2011 at 06:48:15PM +0200, Marco d'Itri wrote:
> On Apr 26, rleigh <rleigh at codelibre.net> wrote:
> 
> > Testing with initramfs-tools (maks/run) with current unstable shows
> > udev appearing to work correctly with it using /dev/.udev when /run
> > is not present on the host system.  And also with /run present on
> Did you check with LVM and that all its persistent symlinks are still
> there?

I created a new kvm VM this morning which uses LVM, so I'll test
all the combinations later tonight.

> > In a kvm VM, I do see some errors from udev at startup:
> These are unrelated and harmless (the errors are old, only the message
> is new).
> 
> > > Why does /run should not be noexec?
> > If /run/shm is also on /run (not a separate mount), it needs to be
> > executable.
> Why do we need it executable?

From what I've read from past initscripts and other bug reports, it's
required for mmapping shared memory with PROT_EXEC, but I have not
verified this by writing a testcase.

> > > > Marco, have you tested this upgrade path?  That is /run in the
> > > > initramfs and no /run on the rootfs?  Is udev checking for that and
> > > No, but if the database is not copied to the initramfs then LVM will be
> > > annoyed.
> > Which database is this?  Is this something that the LVM scripts need
> > updating to handle?
> It is /dev/.udev/ or /run/udev/. I do not know exactly how LVM interacts
> with it, just that it must be preserved.

OK.  I feel that doing something like this:

if [ -d /run ] && [ ! -d /root/run ]; then
  mv /run/udev /dev/.udev
(or mv /run/udev /root/dev/.udev)
fi

at the point where we "mount --move" in the initramfs would be the
best action to take.  It preserves the udev state from the
initramfs when it would otherwise be lost.  In the case where
/run also exists on the rootfs, no action needs taking.

When I do the testing in my new VM, I'll test this type of change
as well.


Regards,
Roger

-- 
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