[AGENT++] Broken pipe error with subagent

[Frank Fock]

Hi Claus,

If you need to handle such cases where the broken connection
cannot be detected through OS events, then you will have
to use the AgentXPing PDU to periodically check from the
subagent if the master is still there. If you do not receive
a response for, let's say three, consecutive ping requests
then close the session (and connection) and start a new
session.

Best regards,
Frank

Am 25.11.2012 10:32, schrieb Claus Klein:
> Hi Frank,
>
> We have also an embedded OS with no SIGPIPE,
> In case of a closed peer, there is too no error while write to the socked.
>
> This ends with a closed session by the Master agent (net-snmp), but 
> the subagent
> does not reregister the MIB.
>
> do {
> while((run) && (!mib->get_agentx()->quit())) {
>             req = reqList->receive(4 * 1000); // ms(4 sec)
> if(req) {
>                 mib->process_request(req);
>             } else {
>                 mib->cleanup();
>             }
>         }
>
>         mib->save_all();
>         loopCount = 0;
> // Make sure that all pending set requests which may
> // have locked any resources are terminated and resources
> // are freed before connection to master is reestablished.
>         reqList->terminate_set_requests();
> while((run) && (!mib->init())) {
> #ifdef _WIN32
>             Sleep(2 * 1000); // ms
> #else
> sleep(2); // sec(posix)
> #endif
> if(loopCount++ > 10) {
>                 loopCount = 0;
> // ping the master every 20 sec
>                 mib->ping_master();
>             }
>         }
>     } while((run));
>
> What can I do? quit() (does not break the 1. while rule)
>
> It is not an option to restart the system in this case.
>
>
> Thanks in advance
> Best Regards
> Claus
>
> On 19.11.2012, at 20:15, Frank Fock wrote:
>
>> Hi Claus,
>>
>> The signal SIGPIPE does not exists on Windows. So here it has not the be
>> handled.
>>
>> Best regards,
>> Frank
>>
>> Am 18.09.2012 06:36, schrieb Claus Klein:
>>> Hi,
>>>
>>> I have found that the SIGPIPE signal can also happens at an agentx
>>> subagent when the response is delayed and the master agent (net-snmp
>>> in this case) close the session after timeout:
>>>
>>> agentx/master: close transport
>>> agentx/master: response too late on session 0x39e660
>>> ...
>>>
>>> The subagent examples do not handle this signal?
>>>
>>> So I added the following code to the main:
>>>
>>> // catch SIGPIPE and ignore it this can occur when the master agent dies
>>> // and we are trying to send a delayed responce
>>> #ifndef _WIN32
>>> signal(SIGPIPE, SIG_IGN);
>>> #endif
>>>
>>>
>>> But how can it handled right under Windows?
>>>
>>> Can anyone please help?
>>>
>>> Thanks in advance
>>> Best Regards
>>> Claus
>>>
>>>
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>>> AGENTPP at agentpp.org <mailto:AGENTPP at agentpp.org>
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>>
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>>
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AGENT++
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73257 Koengen, Germany
https://agentpp.com
Phone: +49 7024 8688230
Fax:   +49 7024 8688231