RE: (ITS#6985) sssvlv / greaterThanOrEqual problem

[ctcard@hotmail.com]

>
> > >
> > > I am running slapd built from HEAD on June 30th 2011, with back-sql
> >
> > Can you confirm this issue with another backend, e.g. back-bdb? Bugs
> > specific to back-sql or to interaction with it could receive only marginal
> > attention.
> >
> > p.
> >
>
> I've imported my data into a server with a bdb backend, and I see the same problem.
>
> Looking at the code in sssvlv.c, it uses tavl_find3() to search the values, but the
> code in tavl_find3() looks to me that it only works properly with an exact match
> type of matching rule:
>
> Avlnode *
> tavl_find3( Avlnode *root, const void *data, AVL_CMP fcmp, int *ret )
> {
>     int    cmp = -1, dir;
>     Avlnode *prev = root;
>
>     while ( root != 0 && (cmp = (*fcmp)( data, root->avl_data )) != 0 ) {
>         prev = root;
>         dir = cmp > 0;
>         root = avl_child( root, dir );
>     }
>     *ret = cmp;
>     return root ? root : prev;
> }
>
> since the while loop terminates when the fcmp function returns 0 (i.e. exact match).
>

I think I've worked out where the problem is.
Firstly, there's a comment before tavl_find3() saying 
/*
 * tavl_find2 - returns Avlnode instead of data pointer.
 * tavl_find3 - as above, but returns Avlnode even if no match is found.
 *				also set *ret = last comparison result, or -1 if root == NULL.
 */

but the "or -1 if root == NULL" is not done.

Secondly, if no exact match is found, prev is returned which may point to a node which is less than the search 
node, depending on what the tree looks like, but we really want a pointer to the last node which was greater than
the search node to be returned.

Once these fixes are done, the correct node is returned by tavl_find3 to the call in send_list() in sssvlv.c (line 523).

There is another bug in send_list() in sssvlv.c, at lines 535-544:

			if ( i > 0 ) {
				tmp_node = tavl_end(so->so_tree, TAVL_DIR_RIGHT);
				dir = TAVL_DIR_LEFT;
			} else {
				tmp_node = tavl_end(so->so_tree, TAVL_DIR_LEFT);
				dir = TAVL_DIR_RIGHT;
			}
			for (i=0; tmp_node != cur_node;
				tmp_node = tavl_next( tmp_node, dir ), i++);
			so->so_vlv_target = i;
This code is ok if the cur_node is in the left hand side of the tree, but if it is in the rhs of the tree so_vlv_target is set
to an offset from the end of the list, rather than the beginning.


Chris