Hi I see what you mean. What do you suggest? To insert the entry to local data structure in "create_entry" or to remove the "SNMP_FREE" call? I lean towards the second, if it is possible and will not cause memory issues, since I still don't see how the already exists rows are inserted into local data structure as well. Was I suppose to insert them in "init"?
Naama -----Original Message----- From: dave.shi...@gmail.com [mailto:dave.shi...@gmail.com] On Behalf Of Dave Shield Sent: Tuesday, July 31, 2012 10:56 AM To: Naama Bar Menachem Cc: net-snmp-users@lists.sourceforge.net Subject: Re: How to delete/add line from raw table? On 31 July 2012 08:30, Naama Bar Menachem <naama.barmenac...@novelsat.com> wrote: > There is no double-free problem. The free is only called once and > crashes on the first time. Well *something* is wrong with it! The usual causes of problems with releasing memory are: - freeing a NULL pointer - freeing a pointer twice - freeing a pointer that wasn't allocated dynamically You could try compiling with one of the memory debugging tools (dmalloc, or libefence) to try and analyse where things are going wrong. > However, there is something I don't understand. As I said the data is > not stored locally on the agent, but on kernel. When the device is > loaded, there is always 5 rows in the table. Where those 5 rows are > allocated and stored in the local agent table? The agent typically keeps a local cached version of the underlying table being monitored. This could be a complete copy of all of the data from that table - or else a "skeleton" table, containing a dummy entry for each row of the table (with the actual data being looked up from the kernel in the handler). However this is done, it's usually set up in the 'createEntry' routine. Looking at your code, the entry that is set up in this routine is never actually used. You allocate a memory structure, but the block of code 'XXX - insert entry into local data structure' is empty. So the per-row data structure that you create here is simply dropped. The entry you work with elsewhere is set up within the nsCommonConfigDataForwardPolicyRouteTable_get_entry() routine, and seems to refer to a global buffer (which doesn't need freeing) Hence the cause of the crash is case 3 above. > In addition, I added a new row, and immediately destroyed it. I > printed the address the entry is pointing to, and it seems that in > "create_entry" the allocated entry is pointing to "0x1201f6160", while > on "remove_entry" it is pointing to "0x555aa6dc98". See above. If you are using your own mechanism for retrieving data from the underlying kernel - then you need to extend this to apply to updating values and creating/deleting rows as well. You probably need to replace the *whole* of the createEntry & deleteEntry routines with versions that work with your kernel table. Similarly for the SET processing of the column values. You apply the new values within the Action pass, but don't seem to be reversing this in the Undo pass, if some part of the SET fails. Dave ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
