[Net-snmp-patches] [ net-snmp-Patches-3290705 ] Eradicates file handle leak during HUPs

[SourceForge.net <no...@so...>]

Patches item #3290705, was opened at 2011-04-20 18:42
Message generated for change (Settings changed) made by hardaker
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=312694&aid=3290705&group_id=12694

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: None
Group: None
Status: Open
Resolution: None
>Priority: 4
Private: No
Submitted By: Daniel Ng ()
Assigned to: Nobody/Anonymous (nobody)
Summary: Eradicates file handle leak during HUPs

Initial Comment:
I have noticed that the handling of the Target Address Table ( see
snmpTargetAddrTable_create()) and Target Parameters Table (see
snmpTargetParamTable_create()) during a HUP is not actually done if
callbacks are enabled.

For example, init_snmpTargetAddrEntry() should register a callback for
the SNMPD_CALLBACK_PRE_UPDATE_CONFIG to handle the shutdown of the
Target Address Table. This is how it is currently done for the
Notificaitons Table via:

snmp_register_callback(SNMP_CALLBACK_APPLICATION,
                          SNMPD_CALLBACK_PRE_UPDATE_CONFIG,
                          notifyTable_unregister_notifications, NULL);


The result of this incomplete handling of HUP for the Target Address
and Target Parameters Tables is:
-sockets which are created for each trap sink are never closed (thus
causing File Handle leaks)
-the data structures related to these Tables are never freed (thus
causing memory leaks)

Here's a patch for v5.6. It stops the leaking of file handles, but there is still a memory leak (about 500 bytes per HUP are leaked). The memory leak was always present- it was uncovered by the patch, not introduced by it.

A crash was worked around by commenting out a free() in snmp_transport.c. Not ideal, but if you have any better suggestions I'd love to know!



----------------------------------------------------------------------

Comment By: Wes Hardaker (hardaker)
Date: 2011-05-25 14:07

Message:
Well, unfortunately commenting out the free is definitely not the right
solution.  Do you have a back-trace for when it's crashing?

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=312694&aid=3290705&group_id=12694