From: Octavian Purdila <opurdila@ixiacom•com>
To: Cong Wang <amwang@redhat•com>
Cc: David Miller <davem@davemloft•net>,
Linux Kernel Network Developers <netdev@vger•kernel.org>,
Linux Kernel Developers <linux-kernel@vger•kernel.org>,
"Eric W. Biederman" <ebiederm@xmission•com>
Subject: Re: [net-next PATCH v4 1/3] sysctl: refactor integer handling proc code
Date: Tue, 16 Feb 2010 16:00:54 +0200 [thread overview]
Message-ID: <201002161600.54975.opurdila@ixiacom.com> (raw)
In-Reply-To: <4B7A98C7.3070107@redhat.com>
On Tuesday 16 February 2010 15:08:23 you wrote:
> Octavian Purdila wrote:
> > On Tuesday 16 February 2010 10:41:07 you wrote:
> >>> +
> >>> + if (!write && !first && left && !err)
> >>> + err = proc_put_newline(&buffer, &left);
> >>> + if (write && !err)
> >>> + err = proc_skip_wspace(&buffer, &left);
> >>> + if (err == -EFAULT /* do we really need to check for -EFAULT? */
> >>> || + (write && first))
> >>> + return err ? : -EINVAL;
> >>
> >> The logic here seems messy, adding one or two goto's may help?
> >
> > OK, I'll give it a try.
> >
> > What about the EFAULT check, is that really required?
>
> I think so, it means to keep the errno to user-space when it is EFAULT,
> right? This seems reasonable.
>
The problem I see is that this way we don't actually acknowledge some of the
set values, e.g. say that we have buffer="1 2 3" and length = 100. Although we
do accept values 1, 2 and 3 we don't acknowledge that to the user (as we would
do for, say "1 2 3 4a"), but return -EFAULT.
I think it would be better to skip this check. That means that the user will
get the ack for the 1, 2 and 3 values and next time it continues the write it
will get -EFAULT.
This will of course change the userspace ABI, albeit in a minor way, and it is
not clear to me if doing this is allowed (even if this new approach would be
the correct one).
next prev parent reply other threads:[~2010-02-16 14:00 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-15 22:00 [net-next PATCH v4 0/3] net: reserve ports for applications using fixed port Octavian Purdila
2010-02-15 22:00 ` [net-next PATCH v4 1/3] sysctl: refactor integer handling proc code Octavian Purdila
2010-02-16 8:41 ` Cong Wang
2010-02-16 10:48 ` Octavian Purdila
2010-02-16 13:08 ` Cong Wang
2010-02-16 14:00 ` Octavian Purdila [this message]
2010-02-17 16:31 ` Cong Wang
2010-02-17 21:09 ` Octavian Purdila
2010-02-18 3:58 ` Octavian Purdila
2010-02-16 11:41 ` Octavian Purdila
2010-02-16 13:09 ` Cong Wang
2010-02-16 13:44 ` Octavian Purdila
2010-02-17 16:21 ` Cong Wang
2010-02-17 16:33 ` Eric W. Biederman
2010-02-18 4:25 ` Octavian Purdila
2010-02-15 22:00 ` [net-next PATCH v4 2/3] sysctl: add proc_dobitmap Octavian Purdila
2010-02-16 9:12 ` Cong Wang
2010-02-15 22:00 ` [net-next PATCH v4 3/3] net: reserve ports for applications using fixed port numbers Octavian Purdila
2010-02-16 9:37 ` Cong Wang
2010-02-16 11:06 ` Octavian Purdila
2010-02-16 13:06 ` Cong Wang
2010-02-16 13:20 ` Eric Dumazet
2010-02-17 16:13 ` Cong Wang
2010-02-17 16:39 ` Eric Dumazet
2010-02-17 16:01 ` Octavian Purdila
2010-02-20 8:00 ` Cong Wang
2010-02-16 14:25 ` Octavian Purdila
2010-02-17 16:07 ` Cong Wang
2010-02-16 17:25 ` [net-next PATCH v4 0/3] net: reserve ports for applications using fixed port Eric W. Biederman
2010-02-16 18:04 ` Octavian Purdila
2010-02-16 18:49 ` Eric W. Biederman
2010-02-16 19:51 ` Octavian Purdila
2010-02-16 20:08 ` Eric W. Biederman
2010-02-16 21:22 ` Octavian Purdila
2010-02-17 15:57 ` Cong Wang
2010-02-17 16:10 ` Eric W. Biederman
2010-02-17 16:19 ` Cong Wang
2010-02-17 16:26 ` Eric W. Biederman
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