Messages in this thread | | | From | Octavian Purdila <> | Subject | Re: [net-next PATCH v4 1/3] sysctl: refactor integer handling proc code | Date | Tue, 16 Feb 2010 16:00:54 +0200 |
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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).
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