Re: [PATCH v2 2/2] pcapng: check if writev() returns a partial write

["Mário Kuka" <kuka@cesnet.cz>]

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> As pcapng is used in the dpdk application it writes to a file.
> You could repurpose it to something else, but even a pipe will not
> give partial writes unless you configure the pipe as non-blocking.
>
> Writing to a non-blocking pipe is going to have a load of other problems.
>
> This seems like a purely hypothetical case, can't see why it needs to be addressed.

OK, I'm sending patch v3 which only fixes the IVO_MAX limit issue.
I've removed the changes related to the partial write check.

On 29/07/2022 20:14, Stephen Hemminger wrote:
> On Fri, 29 Jul 2022 19:08:41 +0200
> Mário Kuka <kuka@cesnet.cz> wrote:
>
>>> Since this is being written to a file, handling partial writes makes little
>>> sense. The only case where partial write would happen would be if filesystem
>>> was full. Retrying just adds unnecessary complexity.
>>>
>>> If you really want to track this, then add a dropped counter.
>> But the file descriptor doesn't have to refer to just a regular file, what
>> if it's a socket or a pipe or some device? The pcapng documentation doesn't
>> say anything about any restrictions, so the implementation should be fully
>> generic. What's the point of a function to write packets to a file
>> descriptor
>> where there's a risk that it won't write all the packets or that the
>> file will
>> by corrupted due to a partial write and still not even let me know about
>> it?
> As pcapng is used in the dpdk application it writes to a file.
> You could repurpose it to something else, but even a pipe will not
> give partial writes unless you configure the pipe as non-blocking.
>
> Writing to a non-blocking pipe is going to have a load of other problems.
>
> This seems like a purely hypothetical case, can't see why it needs to be addressed.


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