[AGENT++] agent++: Memory leak in MigGroup

[dominik.vogt at external.thalesgroup.com]

On Wed, Aug 11, 2010 at 03:29:39PM +0200, Dominik Vogt wrote:
>    On Wed, Aug 11, 2010 at 03:21:05PM +0200, Frank Fock wrote:
>    >    The first is a memory leak (when the objects in the group could not
>    be
>    >    added). This have to be fixed. The other is not a leak and is
>    intended
>    >    behavior. The Mib class is always responsible for deleting MibEntry
>    >    objects.
> 
>    The Mib class *does not* delete the items in the MibGroup.
>    Valgrind reports the memory to be leaked by losing the last
>    reference to the memory when the Mib is deleted.

Allright, this is what happens:

If an object with a certain Oid is added twice to a MibGroup*, the
items that are added in the *first* registration are leaked.  The
leak can be seen with this group definition:

  struct foo : public MibGroup
  {
  	foo();
  };
  
  foo::foo()
  	: MibGroup("1.3.6.1.2.1.1", "systemGroup") 
  {
	MibEntry *p1;
	MibEntry *p2;

  	add((p1 = new sysDescr("bar")));
  	add((p2 = new sysDescr("bar")));
  }

With this snippet of code, the memory referenced by *p1*,
allocated with the first call of new, is lost.  However, if I add

  delete p1;

at the end of the function, memory gets corrupted.  Deep
investigations into the memory structures stored in the Mib object
have shown me that a mix of memory allocated by the first and the
second new is stored in the Mib object.  There must be something
wrong in the code that checks if a certain oid already exists in
the Mib object.

Ciao

Dominik ^_^  ^_^

* Note:  Similar memory corruption may happen if simple MibEntry
objects with the same oid are added to the mid; I did not test
that case.

-- 

Doominik Vogt