Look at the following scenario: A requires B. B, in the %post, runs an activity that is essential for A. If you install A with YUM, and that activity of B fails, YUM will install A anyway, but A will not be functional because the %post of B failed. Checking that the %post of B completed successfully in %pre of A will prevent that situation. -----Original Message----- From: Rpm-list [mailto:rpm-list-bounces@xxxxxxxxxxxxx] On Behalf Of Panu Matilainen Sent: Wednesday, December 03, 2014 8:48 AM To: rpm-list@xxxxxxxxxxxxx Subject: Re: %pre scripts with a non-zero exit status. On 12/02/2014 06:55 PM, Eran Ben Natan wrote: > That is exactly the purpose of the %pre – to verify that all > prerequisites are met, so, yes, this is a good idea. That is what dependencies are for. Doing such checks in %pre is generally speaking a bad idea. And no, that is not what %pre exists for. Not at all! > > *From:*Rpm-list [mailto:rpm-list-bounces@xxxxxxxxxxxxx] *On Behalf Of *doc > *Sent:* Tuesday, December 02, 2014 6:52 PM > *To:* rpm-list@xxxxxxxxxxxxx > *Subject:* %pre scripts with a non-zero exit status. > > I'm being asked to create a %pre scriptlet which if certain > configuration conditions are not met will not install the rpm package. > > Is this a good idea? > > My understanding of rpm scriptlets is that they should always (except > under extreme conditions) exit with a status of 0. Needless to say, > these rpms with the %pre failures would be installed by rpm, yum and > zypper. Indeed. %pre (and %pretrans in newer rpm versions) has the capability to cancel out package installation, %preun similarly can cancel uninstall. Doing so is almost always a terrible idea however, because the scriptlets are executed at a point where its not possible to cancel other packages. So when you're using %pre to cancel package installation, you're pulling the carpet underneath everything else in the same transaction: your package does not know what other packages might depend on it. Non-zero exit from %pre/%preun should be a last-gasp measure for preventing install. Its basically okay if you know the package will ALWAYS be installed alone in a transaction, but there's usually no way to guarantee such a thing. - Panu - _______________________________________________ Rpm-list mailing list Rpm-list@xxxxxxxxxxxxx http://lists.rpm.org/mailman/listinfo/rpm-list _______________________________________________ Rpm-list mailing list Rpm-list@xxxxxxxxxxxxx http://lists.rpm.org/mailman/listinfo/rpm-list
