[Pkg-sysvinit-devel] Bug#638019: /run/initctl

[Roger Leigh]

On Sun, Jan 08, 2012 at 03:34:13PM +0100, Robert Millan wrote:
> El 8 de gener de 2012 15:14, Roger Leigh <rleigh at codelibre.net> ha escrit:
> > path, "init u" on its own won't work.  I would suggest this strategy:
> >
> > 1) Create /run/initctl
> > 2) Symlink /dev/initctl (or /etc/.initctl) to /run/initctl
> > 3) Send SIGUSR1 to init
> >   → init reopens using the old path, but is redirected to use
> >     /run/initctl
> > 4) Wait for that action to complete
> > 5) Run "init q" to re-exec init.  The new init will use the new
> >   paths
> > 6) Delete the no-longer-needed /dev/initctl (or /etc/.initctl).
> 
> Seems good, but I dislike step 4, as it opens the door for race conditions.
> 
> Can't we just remove steps 4 and 5?  I think everything would work without
> them.

If we don't do that, then we are left running the old /sbin/init binary,
which is an important part of the upgrade.  If there's a way to detect
a listener on a pipe, we could do that.  Or if telinit/init return an
error code, we can loop until it succeeds.


Regards,
Roger

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