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From: Giacomo Tesio <giacomo@tesio.it>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] create/create race
Date: Wed, 30 Nov 2016 17:16:23 +0100	[thread overview]
Message-ID: <CAHL7psGpqyb2T+H++eh-yOoVQqQBS1yu-Tnj_BfJKtNDY=zNLQ@mail.gmail.com> (raw)
In-Reply-To: <1f7987e063f01beaba1c53723d3f5b97@felloff.net>

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2016-11-30 16:40 GMT+01:00 <cinap_lenrek@felloff.net>:

> this makes no sense to me. the whole point of create with OEXCL is that
> it is atomic and it will *NOT* try to truncate-open the file when it
> already
> exist. OEXCL means just sending the Tcreate and nothing else. why is that
> not
> already what you try todo with your new create syscall?
>
> can you please state the problem that you are trying to fix?
>

Well, describing the whole picture would take a while (and would move the
thread topic to other unusual aspects of its design), but one of the reason
that can explain my question is that I want to simplify the kernel code as
much as possible, moving to user space all that can be moved without
affecting the system security.
In the end I'd like to get few orthogonal syscalls, so that you cannot
obtain the exact effect of one in term of 2 or more other.

I know that this seem a bit theoretical, but it's just a starting point and
has a lot of really pragmatic implications in my research project.
Stated in a different way, I want to keep it simple, and user space code is
usually simpler than kernel space code.


Btw, actually, I'm not proposing a change to Plan 9 or debating about its
design.
I'm just asking about the reasoning behind this specific choice, because I
guess that it's deeper than it seem (so much that I cannot grasp it by
reading the code).


Also I'm looking for "instances that *want* the existing effect", as
Charles perfectly described them, something that break without it, so that
I can dive deeper into the matter.


Giacomo

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  reply	other threads:[~2016-11-30 16:16 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-24 21:25 Giacomo Tesio
2016-11-30 11:04 ` Giacomo Tesio
2016-11-30 11:19   ` cinap_lenrek
2016-11-30 13:14   ` G. David Butler
2016-11-30 13:32     ` cinap_lenrek
2016-11-30 13:53       ` Charles Forsyth
2016-11-30 15:02         ` Giacomo Tesio
2016-11-30 15:08           ` Charles Forsyth
2016-11-30 15:28             ` Giacomo Tesio
2016-11-30 15:34               ` Charles Forsyth
2016-11-30 15:40               ` cinap_lenrek
2016-11-30 16:16                 ` Giacomo Tesio [this message]
2016-11-30 21:51                   ` Charles Forsyth
2016-11-30 21:53                     ` Charles Forsyth
2016-11-30 23:15                       ` Giacomo Tesio

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