[AGENT++] Memory corruptions with MibComplexEntry subclass get_next_request

[Reetesh Ranjan]

Frank,

Thanks for the help. It solved the issue.

I am now having some issue while trying to change the read/write
community from default "public". I tried to call
RequestList::set_read_community(), RequestList::set_write_community();
but just this addition to the earlier code starts causing another
memory corruption. I am creating an OctetStr object out of the string
literal for my community string, and call the set_write_community
method on the RequestList just after creating it. It leads to a memory
corruption. Remove the call to set_write_community and things work
fine again. Any inputs?

Thanks,
Reetesh

On Wed, Aug 18, 2010 at 10:06 PM, Frank Fock <fock at agentpp.com> wrote:
> You cannot assign an array of unint8 as value (and the wrong length).
> Simply assign a valid SnmpSyntax object and all will be fine.
>
> Frank
>
> On 18.08.2010 16:23, Reetesh Ranjan wrote:
>> I have done a simple derivation MibComplexEntry and following is the
>> derived get_next_request function (as per suggestion by Frank in
>> another thread from me).
>>
>> void SDCFsMibHandler::get_next_request(Request * request, int ind)
>> {
>>      uint8 lResponse[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
>>
>>      Vbx vb(request->get_oid(ind));
>>
>>      vb.set_value(lResponse, sizeof lResponse);
>>
>>      request->finish(ind, vb);
>> }
>>
>> This code is leading to memory corruption. Dmalloc finds an error 67
>> after function exits (but I am not sure whether because of local vars
>> destructed or somewhere later in the flow). When I replace the local
>> variable vb with an allocated one, then similar error comes for heap.
>> I am trying to do a simple operation of providing a value in the
>> get-next response.
>>
>> Here are the class definition and all methods implemented/derived:
>>
>> class SDCFsMibHandler : public MibComplexEntry
>> {
>> public:
>>      // constructor
>>      SDCFsMibHandler();
>>
>>      // destructor
>>      virtual
>>      ~SDCFsMibHandler() { }
>>
>>     // Needed to implement pure virtual functions (but are dummy)
>>    virtual MibEntry * clone() { return NULL; }
>>
>>    virtual OidxPtr max_key(void) { return NULL; }
>>
>>    virtual void get_request(Request *, int) { /* no-op */ }
>>
>>    virtual int prepare_set_request(Request*, int&) { return SNMP_ERROR_SUCCESS; }
>>
>>    virtual int undo_set_request(Request*, int&) { return SNMP_ERROR_SUCCESS; }
>>
>>    virtual void cleanup_set_request(Request*, int&) { }
>>
>>    // Important derived functions
>>    virtual void
>>    get_next_request(Request*, int);
>>
>>    virtual Oidx find_succ(const Oidx&  a, Request * req=NULL);
>>
>>    virtual int commit_set_request(Request*, int);
>> }
>>
>> SDCFsMibHandler::SDCFsMibHandler()
>>      : MibComplexEntry("1.3.1.4.1.108.1.200.1", READWRITE)
>> { }
>>
>> Oidx SDCFsMibHandler::find_succ(const Oidx&  a, Request * req)
>> {
>>      Oidx l = a.next_peer();
>>      return(l);
>> }
>>
>> My snmp processing code is lifted from the examples. Could you please
>> help me with any information on this?
>>
>> Thanks,
>> Reetesh
>> _______________________________________________
>> AGENTPP mailing list
>> AGENTPP at agentpp.org
>> http://lists.agentpp.org/mailman/listinfo/agentpp
>
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