Bug#975591: insserv/update-rc.d coordination missing (was Re: Canonical method to locally disable an init script?)

[Thorsten Glaser]

On Wed, 25 Nov 2020, Bob Proulx wrote:

> Thorsten Glaser wrote:

> > So using disable is correct, defaults-disabled and remove isn't,

Right, I now figured out it isn’t.

>     root at angst:/etc# find /etc/rc?.d/ -name '*bind9'
>     /etc/rc0.d/K04bind9
>     /etc/rc1.d/K04bind9
>     /etc/rc2.d/K04bind9
>     /etc/rc3.d/K04bind9
>     /etc/rc4.d/K04bind9
>     /etc/rc5.d/K04bind9
>     /etc/rc6.d/K04bind9
> 
>     root at angst:/etc# apt-get install --reinstall bind9
[…]
> It warned that they were different from the LSB headers in the init
> script.  Because they were different.  And that could be any of the
> possible differences.  But it did not reset them.
> 
>     root at angst:/etc# find /etc/rc?.d -name '*bind9'
>     /etc/rc0.d/K04bind9
>     /etc/rc1.d/K04bind9
>     /etc/rc2.d/K04bind9
>     /etc/rc3.d/K04bind9
>     /etc/rc4.d/K04bind9
>     /etc/rc5.d/K04bind9
>     /etc/rc6.d/K04bind9

Right. I can verify that.

>     root at angst:/etc# find /etc/rc?.d -name '*bind9' -delete
>     root at angst:/etc# find /etc/rc?.d -name '*bind9'
> 
> All removed.  The re-install will reset the links to the defaults.
> 
>     root at angst:/etc# apt-get install --reinstall bind9
[…]
>     root at angst:/etc# find /etc/rc?.d -name '*bind9'
>     /etc/rc0.d/K04bind9
>     /etc/rc1.d/K04bind9
>     /etc/rc2.d/S03bind9
>     /etc/rc3.d/S03bind9
>     /etc/rc4.d/S03bind9
>     /etc/rc5.d/S03bind9
>     /etc/rc6.d/K04bind9

Yes, and that MUST NOT happen.

> Removing the S* links instead of disabling them with a K* link.  But
> leaving the K* links so it is an installed configuration.  Then

If the local administrator actively disables an init script, e.g. by
update-rc.d remove, it MUST NOT be re-added later. (This MIGHT require
insserv and update-rc.d to coordinate on “manually removed” state, but
this state MUST NOT be the presence of ANY symlinks for that script.)

Rationale:

Disabling an init script is *not* the same as leaving a K link…
because a K link will attempt to stop the service if manually started.
This MUST NOT happen.

Considering raising severity on this as disabling with update-rc.d remove
does not work and disabling with update-rc.d disable wrongly leaves any K
links around which causes unrelated software, that is, a manually started
service, to be broken, that is, stopped.

I just had this happen, so it isn’t an academic mind exercise.

bye,
//mirabilos
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