[syslog-ng] [Non-DoD Source] Re: Syslog 3.5 (pipe file issue)

[László Várady]

Hi,

As Laci pointed out, this is an expected behavior.
Named pipes are not regular files, the "file size" is always 0 byte.

>From https://linux.die.net/man/4/fifo:
*When processes are exchanging data via the FIFO, the kernel passes all
data internally without writing it to the file system.*

If you are interested in the capacity of named pipes, you can read about
this here:
https://linux.die.net/man/7/pipe (Chapter name: Pipe capacity)

--
László Várady

On Fri, Oct 27, 2017 at 4:56 PM Amin, Jitesh CTR (US) <
jitesh.amin.ctr at mail.mil> wrote:

> Hi Laci,
> So we can create named pipe object with filename successfully.
>
> But the then the file always shows 0 bytes in size even after data is
> being written to this file. Additionally the timestamp on this file never
> changes (as new data get's written and so I would assume that modify date
> on file would also be updated).
>
> Thanks
> Jitesh
> ------------------------------
> *From:* syslog-ng [syslog-ng-bounces at lists.balabit.hu] on behalf of
> Szemere, László [laszlo.szemere at balabit.com]
> *Sent:* Friday, October 27, 2017 9:46 AM
> *To:* Syslog-ng users' and developers' mailing list
> *Subject:* [Non-DoD Source] Re: [syslog-ng] Syslog 3.5 (pipe file issue)
>
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>
>
> Hello Jitesh,
>
>  I am afraid I can not clearly understand your problem. Since OSE 3.0.2, a
> named pipe destination creates a new pipe object automatically with the
> predefined filename. (Caution-
> https://www.balabit.com/documents/syslog-ng-ose-3.11-guides/en/syslog-ng-ose-guide-admin/html-single/index.html#configuring-destinations-pipe
>  < Caution-
> https://www.balabit.com/documents/syslog-ng-ose-3.11-guides/en/syslog-ng-ose-guide-admin/html-single/index.html#configuring-destinations-pipe
>  > )
>
>  For me, this is the expected behavior of named pipes (man page: Caution-
> http://man7.org/linux/man-pages/man1/mkfifo.1.html < Caution-
> http://man7.org/linux/man-pages/man1/mkfifo.1.html >  further information
> on level 3: Caution-http://man7.org/linux/man-pages/man3/mkfifo.3.html
>  < Caution-http://man7.org/linux/man-pages/man3/mkfifo.3.html > ). Please
> try to rephrase your question, to give us more understanding about your use
> case.
>
> Br,
> Laci
>
>
>
>
> On Fri, Oct 27, 2017 at 2:42 PM, Amin, Jitesh CTR (US) <
> jitesh.amin.ctr at mail.mil < Caution-mailto:jitesh.amin.ctr at mail.mil > >
> wrote:
>
>> Hi,
>> We have the syslog-ng 3.5 installed on Linux OS. We are trying to use the
>> pipe function (to pipe data to the log file). This pipe file is FIFO.
>>
>> One of the issues we are seeing is that, the file size of this pipe file
>> is always ZERO and never grows and second the timestampe on the file never
>> updates or changes.
>>
>> Though when we do a "cat pipefilename" command we do see contents of the
>> file.
>>
>> Can you please let us know what we could be doing wrong or any feedback
>> on how to resolve the issue?
>>
>> Thanks
>> Jitesh
>>
>>
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