Re: [ANNOUNCEMENT] TEST RELEASE: Cygwin 2.3.0-0.7

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

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On Nov  6 20:35, Achim Gratz wrote:
> Corinna Vinschen writes:
> > One of the sore points is performance hit when
> > using AuthZ to fetch the effective user permissions.  How's your
> > impression?  Is it noticable in your environment?
> 
> Aside from the somewhat contrived example I already gave, the normal
> day-to-day operation with the snapshot so far was uneventful.  Other
> users besides me have the snapshot installed since about a week, so if
> there were any catastrophic degradation I should know by now (I did ask
> them to report back if they see something that's different as before).

Sounds good.  Nevertheless, I'll release 2.3.0-1 and an 2.4.0-0.1 test
release today.

It occured to me that there's a potential way to tweak the code to
reduce the number of AuthZ calls.  Consider:

If the user has its own ACE, and if user_perms | all_group_perms |
other_perms == user_perms, or if user_perms are already RWX, then there
are no groups which could have more permissions than the user already
owns all by itself.

Good examples of this scenario are typical default POSIX perms 644 or
755 or even 775, used a lot throughout existing Cygwin trees.  None of
them require to check with AuthZ, but the AuthZ test is performed
indiscriminately if it's a not one of the "new" Cygwin ACLs.

I'll look into that this week.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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