Re: Config file statement ordering (Was: (ITS#4848) Another slapd startup segfault)

[Pierangelo Masarati <ando@sys-net.it>]

Pierangelo Masarati wrote:

> that is, if both the database and the overlay allow back-config, there
> are cases in which config_set_vals() can be called with (arg_type &
> ARG_OFFSET) and the c->be points to the database's structure while c->bi
> points to the overlay's structure, and the config statement refers to
> the database although appearing after the overlay's instantiation.
> 
> This is Bad (TM) and should be avoided.  However, for example, I have
> special needs in back-meta that require to allow overlay instantiation
> __before__ the database configuration is complete (in that case, I need
> an overlay to be instantiated before targets are defined, so that the
> overlay can get per-target configuration parameters much like the
> underlying database does).  This may defer introduction of back-config
> support for back-meta.


Please disregard the above patch, which is incorrect as well.  I think
the right way to address the problem of selecting the right context for
configure statements definitely consists in attaching into the
ConfigTable a Conf->bi pointer to the BackendInfo that ConfigTable entry
belongs to.  This would allow to determine if the ConfigTable entry
belongs to the underlying database, to an overlay, to the frontend or
whatever, by comparing the BackendInfo* with that of the above stuff.
Something like:

if ( c->be ) {
	if ( !overlay_is_over( c->be ) ) {
		ptr = c->be->be_private;
	} else if (((slap_overinfo *)c->be->bd_info)->oi_orig
		== Conf->bi )
	{
		ptr = c->be->be_private;
	}
}

if ( ptr == NULL && c->bi && c->bi->bi_type == Conf->bi->bi_type ) {
	ptr = c->bi->bi_private;
} else {
	// error
}

or whatever.



Ing. Pierangelo Masarati
OpenLDAP Core Team

SysNet s.n.c.
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