Re: interesting question
Package: packaging-manual
Version: 3.1.1.1
On Tue, Apr 04, 2000 at 12:48:27PM -0700, Joey Hess wrote to -devel:
> Here's an interesting hypothetical question we came up with at the
> office:
>
> Suppose a .deb is released that does rm -rf / in its prerm. We know it
> has been installed on a bunch of machines all over the place. How can we
> safely upgrade them?
>
> [explanation of difficulty snipped]
I just wrote a long thought about similar problems, and then realised
that I didn't understand the packaging manual, section 6.3, para 1.
Could I suggest the following rewording to clarify the issue (which
more clearly describes the behaviour of dpkg):
-----
1. If a version the package is already installed, call
old-prerm upgrade new-version
- 2. If this gives an error (ie, a non-zero exit status), dpkg
- will attempt instead:
+ 2. If the script runs but exits with a non-zero exit status, dpkg
+ will attempt:
new-prerm failed-upgrade old-version
Error unwind, for both the above cases:
old-postinst abort-upgrade new-version
-----
Still doesn't solve the problem Joey has, though. I wonder whether
the possibility of having a "prerm-override" file would help, or
whether it would just complicate things unnecessarily. Although I
could imagine situations in which non-malicious but still serious bugs
in prerm's could cause similar situations to arise. Basically, in the
current setup, prerm bugs are mostly unfixable.
Julian
--
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Julian Gilbey, Dept of Maths, QMW, Univ. of London. J.D.Gilbey@qmw.ac.uk
Debian GNU/Linux Developer, see http://www.debian.org/~jdg
Donate free food to the world's hungry: see http://www.thehungersite.com/
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