Bob Proulx writes:
> Meeuwissen Olaf wrote:
>> I just upgraded a number of packages on a machine where I had
>> manually added a `kvm` group. This caused the postinst script
>> to fail with
>>
>> The group `kvm' already exists and is not a system group. Exiting.
>>
>> leaving `eudev` unconfigured.
>
> I noticed this on Sunday and also investigated. And then today
> another user DeepDive on #devuan IRC reported the same problem.
> Therefore I am raising the severity to important due to the effect
> this has for many users.
Thanks. I was wondering whether to do so on the initial report.
>> I don't know if the `kvm` *must* be a system group but things
>> have been working fine for me with a non-system group. As long as
>> a non-system `kvm` group exists, configuring `eudev` will fail.
>> This is easily confirmed with
>>
>> $ sudo dpkg-reconfigure eudev
>> The group `kvm' already exists and is not a system group. Exiting.
>>
>> Changing the group to a system group fixes this behaviour.
>>
>> I worked around the issue by appending `|| true` in the postscript
>> to the `adduser` command that tries to create the system group.
>>
>> If the `kvm` group does not have to be a system group, I would expect
>> configuration to succeed if a non-system `kvm` group is present.
>
> But the code used in the postinst is problematic. The code is this.
> (I know the web version does not show indentation. Imagine the code
> being indented. Check the original files.)
>
> #!/bin/sh
> set -e
> ...
> case "$1" in
> configure)
> ...
> # Add new system group used by udev rules
> addgroup --quiet --system input
>
> # Make /dev/kvm accessible to kvm group
> addgroup --quiet --system kvm
>
> # Make /dev/dri/renderD* accessible to render group
> addgroup --quiet --system render
>
> Those are unconditional additions. Which means that if the addgroup
> returns a non-zero exit code then due to the set -e the configure
> fails and the package is left unconfigured.
>
> It is true that the addgroup would return 0 (success) if it would not
> need to do the action. But if the user has already locally configured
> an account user or group then that previously existing configuration
> should be maintained.
>
> Therefore group addition should not be unconditional. It should be
> conditional upon the group not already existing. I present two
> alternative examples from existing packages that handle this in two
> different ways.
>
> The first from postfix. The "try it and see" method.
>
> cd ${CHROOT}
> # make sure that the postfix user exists. Simplest portable way to check is to
> # chown something, so we'll create the directories that we need here.
> makedir private root:root 700
> chgrp postfix private 2>/dev/null ||
> addgroup --system postfix
> chown postfix private 2>/dev/null ||
> adduser --system --home ${CHROOT} --no-create-home --disabled-password --ingroup postfix postfix
>
> The second from libvirt-daemon-system. The "check it and see" method.
>
> if ! getent group libvirt >/dev/null; then
> addgroup --quiet --system libvirt
> fi
> if ! getent group kvm >/dev/null; then
> addgroup --quiet --system kvm
> fi
>
> Again for the web display please imagine the above having indentation.
>
> And so either way seems good and acceptable. I would probably do the
> same thing libvirt-daemon-system is doing as that is simple enough.
I would also go the libvirt-daemon-system way. It more clearly states
what is going on.
> Here is a suggested fix for this.
>
> # Add new system group used by udev rules
> if ! getent group input >/dev/null; then
> addgroup --quiet --system input
> fi
>
> # Make /dev/kvm accessible to kvm group
> if ! getent group kvm >/dev/null; then
> addgroup --quiet --system kvm
> fi
>
> # Make /dev/dri/renderD* accessible to render group
> if ! getent group render >/dev/null; then
> addgroup --quiet --system render
> fi
>
> Thank you for maintaining eudev in Devuan! :-)
And thank you for actually suggesting a fix!
Hope this helps,
--
Olaf Meeuwissen, LPIC-2 FLOSS Engineer -- EPSON AVASYS CORPORATION
Free Software Foundation Associate Member since 2004-01-27
Support Free Software https://my.fsf.org/donate
Join the Free Software Foundation https://my.fsf.org/join
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[devuan-dev] bug#548: [EXTERNAL] Re…
