A quick snippet for you:
add_action( 'pre_get_posts', 'filtre');
function filtre($query) {
//echo '<pre>'.print_r($query->query_vars['post_type'], true).'</pre>';
switch($query->query_vars['post_type']){
case 'attachment': // Media library
if( current_user_can('manage_own_media') ) $query->set('author', get_current_user_id() );
break;
case 'post': // Posts
if( current_user_can('manage_own_posts') ) $query->set('author', get_current_user_id() );
break;
case 'page': // Pages
if( current_user_can('manage_own_pages') ) $query->set('author', get_current_user_id() );
break;
} // switch post_type
return $query;
}
Of course this is assuming that there are custom permissions set up using the User Role Editor!
