Messages in this thread | | | Date | Thu, 18 Feb 2010 00:31:45 +0800 | From | Cong Wang <> | Subject | Re: [net-next PATCH v4 1/3] sysctl: refactor integer handling proc code |
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Octavian Purdila wrote: > 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). >
I think the right behavior is accept "1 2 3" and return the number of bytes that we accept.
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