[OpenSIPS-Users] FIFO very fragile

[Dave Singer]

Are you actually able to get results out of the reply fifo?
It's been a long time since I created my bash fifo script so I don't
remember all the particulars of what I ran into.
It can be important to start the read fifo before sending the command

Hear is a snippet from a bash fifo I did.

trap "\rm -f $dlg $fifo_reply ${fifo_answer}* 2> /dev/null; exit 1" 0
if [ ! -w $FIFO ] ; then # can I write to FIFO server?
        echo "Error opening ser's FIFO $FIFO" >> $DEBUG_OUT
        echo "FAILED"
        exit 1
fi
mkdir -p $fifo_dir 2> /dev/null
mkfifo $fifo_reply # create a reply FIFO
if [ $? -ne 0 ] ; then
        echo "error opening reply fifo $fifo_reply" >> $DEBUG_OUT
        echo "FAILED"
        exit 1
fi
chmod a+w $fifo_reply
# start reader now so that it is ready for replies
# immediately after a request is out
cat < $fifo_reply > $dlg  &
fifo_job="$!"

# set trap to cleanup in case of problems or outside kill
trap "kill -9 $fifo_job $fifo_answer_job 2>1 >> $DEBUG_OUT ;  exit 1" 0
# finally actually push command to the fifo
echo "reply pid: $fifo_job, reply fifo: $fifo_reply" >> $DEBUG_OUT

You may want to just use the fifo handeling built into opensipsctl
eg:
/path/opensipsctl fifo ps

Dave


On Mon, May 9, 2011 at 1:42 PM, Brett Nemeroff <brett at nemeroff.com> wrote:

> Dave,
> I don't think those are the issues. First of all, if I supply the full path
> to the reply fifo, I get an error message that the filename is invalid. More
> importantly, it doesn't work. :) without the full path, it does work.
>
> Secondly, I don't think it's SELinux issue because it *does work*
> repeatedly over and over. But an extra carriage return spoils the fun for
> everyone and I can't fix it without restarting opensips.
>
> Do you believe SELinux could cause an issue like that?
> Thanks!
> -Brett
>
>
> On Mon, May 9, 2011 at 3:39 PM, Dave Singer <dave.dorasinger at gmail.com>wrote:
>
>> Brett,
>> I believe you need the full path to the reply fifo.
>> Try:
>> echo -e ":address_dump:/tmp/my_fifo\n\n" > /tmp/opensips_fifo
>>
>> you may also have a permissions ( chmod a+w /tmp/my_fifo ) and/or SELinux
>> issue (very likely if SELinux is enabled, I posted a howto for SELinux in
>> the list a number of months back)
>>
>> Dave
>>
>> On Mon, May 9, 2011 at 9:40 AM, Brett Nemeroff <brett at nemeroff.com>wrote:
>>
>>> Hello List,
>>> So I've been doing some testing with the mi_fifo and found that it
>>> appears to be really fragile. Here's what I've done:
>>>
>>> mkfifo /tmp/my_fifo
>>> cat /tmp/my_fifo&
>>> echo -e ":address_dump:my_fifo\n\n" > /tmp/opensips_fifo
>>> *returns*
>>> 200 OK
>>>   48 <1.2.3.4,2, 0, 0, NULL, NULL>
>>> ** cat process ends
>>> cat /tmp/my_fifo&
>>> echo -e ":address_dump:my_fifo\n\n" > /tmp/opensips_fifo
>>> ** nothing
>>>
>>> At this point, I can't make the fifo work again until I restart opensips.
>>> If I detach from the fifo (kill the cat, so to speak), and reattach it
>>> doesn't work. Nothing seems to make it responsive again. At first I though
>>> something was horribly broken, but then I removed one of my \n from the fifo
>>> command and now it works "as expected". Two new-lines shouldn't break the
>>> fifo, right?
>>>
>>> Thanks!
>>> -Brett
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Users mailing list
>>> Users at lists.opensips.org
>>> http://lists.opensips.org/cgi-bin/mailman/listinfo/users
>>>
>>>
>>
>>
>> --
>> David Singer
>>
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>> http://lists.opensips.org/cgi-bin/mailman/listinfo/users
>>
>>
>
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>


-- 
David Singer
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