An idea on extending the "Package users" approach

Tushar Teredesai tushar at linuxfromscratch.org
Tue Jan 6 12:35:07 PST 2009


On Tue, Jan 6, 2009 at 1:31 PM, Angel Tsankov <fn42551 at fmi.uni-sofia.bg> wrote:
> Tushar Teredesai wrote:
>> On Sun, Jan 4, 2009 at 5:12 PM, Angel Tsankov
>> <fn42551 at fmi.uni-sofia.bg> wrote:
>>> In his hint "Package users" Matthias Benkmann recommends to name the
>>> primary group of a package user after the user name.  But why
>>> duplicate information instead of extending it?!
>>
>> Having username=groupname is helpful in cases where the user/group
>> needs to be changed to root for setuid/setgid scripts.
>>
> So?

If you do a chmod root /usr/bin/crontab, then after the operation you
do not know which package /usr/bin/crontab just by doing a ls -l
/usr/bin/crontab. See the TIP at the end of Section 4.4 of the
hint[1].

>
>>>  Couldn't we name the primary group after the
>>> package (just as he suggests) but name the package user after the
>>> package *and* the package version?  This would make it very easy to
>>> find which version or versions of a package are installed (provided
>>> that when removing version V of package P *all* files belonging to
>>> the respective user are removed).  Does anyone see any flaws of this
>>> idea?
>>
>> Lot of file clashes between users. Say you install foo-1.0 and then
>> upgrade to foo-1.2. Generally, there will be lot of files that will be
>> common to both foo-1.0 and foo-1.2. User foo-1.2 cannot update these
>> files belonging to foo-1.0 without manual intervention.
>>
> Upgrading foo-1.0 to foo-1.2 should go without problem as both users foo-1.0
> and foo-1.2 belong to the same group -- foo.
>

foo-1.0 and foo-1.2 are separate users. foo-1.2 will not be able to
overwrite files belonging to foo-1.0 unless you modify the
permissions. See Section 4.6 of the hint[1].

[1] http://www.linuxfromscratch.org/hints/downloads/files/more_control_and_pkg_man.txt
-- 
Tushar Teredesai
   mailto:tushar at linuxfromscratch.org
   http://www.linuxfromscratch.org/~tushar/



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