*: Convert list_delete(struct list *) to ** to allow nulling

Convert the list_delete(struct list *) function to use
struct list **.  This is to allow the list pointer to be nulled.

I keep running into uses of this list_delete function where we
forget to set the returned pointer to NULL and attempt to use
it and then experience a crash, usually after the developer
has long since left the building.

Let's make the api explicit in it setting the list pointer
to null.

Cynical Prediction:  This code will expose a attempt
to use the NULL'ed list pointer in some obscure bit
of code.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

6 files changed, 20 insertions, 21 deletions

diff --git a/bgpd/rfapi/bgp_rfapi_cfg.c b/bgpd/rfapi/bgp_rfapi_cfg.c
index 3dffb59d1..5ae27a287 100644
--- a/bgpd/rfapi/bgp_rfapi_cfg.c
+++ b/bgpd/rfapi/bgp_rfapi_cfg.c
@@ -2327,8 +2327,7 @@ static void bgp_rfapi_delete_nve_group(struct vty *vty, /* NULL = no output */
 			listnode_delete(rfg->nves, rfd);
 			listnode_add(orphaned_nves, rfd);
 		}
-		list_delete(rfg->nves);
-		rfg->nves = NULL;
+		list_delete_and_null(&rfg->nves);
 	}
 
 	/* delete it */
@@ -2405,7 +2404,7 @@ static void bgp_rfapi_delete_nve_group(struct vty *vty, /* NULL = no output */
 			if (vty)
 				vty_out(vty, "\n");
 		}
-		list_delete(orphaned_nves);
+		list_delete_and_null(&orphaned_nves);
 	}
 }
 
@@ -3420,7 +3419,7 @@ static void bgp_rfapi_delete_l2_group(struct vty *vty, /* NULL = no output */
 	if (rfg->rt_export_list)
 		ecommunity_free(&rfg->rt_export_list);
 	if (rfg->labels)
-		list_delete(rfg->labels);
+		list_delete_and_null(&rfg->labels);
 	if (rfg->rfp_cfg)
 		XFREE(MTYPE_RFAPI_RFP_GROUP_CFG, rfg->rfp_cfg);
 	listnode_delete(bgp->rfapi_cfg->l2_groups, rfg);
@@ -3825,10 +3824,10 @@ void bgp_rfapi_cfg_destroy(struct bgp *bgp, struct rfapi_cfg *h)
 	bgp_rfapi_delete_named_nve_group(NULL, bgp, NULL, RFAPI_GROUP_CFG_MAX);
 	bgp_rfapi_delete_named_l2_group(NULL, bgp, NULL);
 	if (h->l2_groups != NULL)
-		list_delete(h->l2_groups);
-	list_delete(h->nve_groups_sequential);
-	list_delete(h->rfg_export_direct_bgp_l);
-	list_delete(h->rfg_export_zebra_l);
+		list_delete_and_null(&h->l2_groups);
+	list_delete_and_null(&h->nve_groups_sequential);
+	list_delete_and_null(&h->rfg_export_direct_bgp_l);
+	list_delete_and_null(&h->rfg_export_zebra_l);
 	if (h->default_rt_export_list)
 		ecommunity_free(&h->default_rt_export_list);
 	if (h->default_rt_import_list)
diff --git a/bgpd/rfapi/rfapi.c b/bgpd/rfapi/rfapi.c
index 477716caf..6e31b6345 100644
--- a/bgpd/rfapi/rfapi.c
+++ b/bgpd/rfapi/rfapi.c
@@ -490,7 +490,8 @@ void del_vnc_route(struct rfapi_descriptor *rfd,
 		 * Delete local_nexthops list
 		 */
 		if (bi->extra && bi->extra->vnc.export.local_nexthops) {
-			list_delete(bi->extra->vnc.export.local_nexthops);
+			list_delete_and_null(
+				&bi->extra->vnc.export.local_nexthops);
 		}
 
 		bgp_aggregate_decrement(bgp, p, bi, afi, safi);
diff --git a/bgpd/rfapi/rfapi_rib.c b/bgpd/rfapi/rfapi_rib.c
index 748c0c476..92cd1888e 100644
--- a/bgpd/rfapi/rfapi_rib.c
+++ b/bgpd/rfapi/rfapi_rib.c
@@ -510,13 +510,12 @@ void rfapiRibClear(struct rfapi_descriptor *rfd)
 				 */
 				if (pn->info) {
 					if (pn->info != (void *)1) {
-						list_delete(
-							(struct list
-								 *)(pn->info));
+						list_delete_and_null(
+							(struct list **)(&pn->info));
 					}
 					pn->info = NULL;
-					route_unlock_node(
-						pn); /* linklist or 1 deleted */
+					/* linklist or 1 deleted */
+					route_unlock_node(pn);
 				}
 			}
 		}
@@ -1435,7 +1434,7 @@ callback:
 		}
 
 		delete_list->del = (void (*)(void *))rfapi_info_free;
-		list_delete(delete_list);
+		list_delete_and_null(&delete_list);
 	}
 
 	RFAPI_RIB_CHECK_COUNTS(0, 0);
@@ -1450,7 +1449,7 @@ callback:
 		route_unlock_node(pn);
 	}
 	if (lPendCost) {
-		list_delete(lPendCost);
+		list_delete_and_null(&lPendCost);
 		pn->info = NULL;
 		route_unlock_node(pn);
 	}
@@ -1634,7 +1633,7 @@ void rfapiRibUpdatePendingNode(
 	 */
 	if (pn->info) {
 		if (pn->info != (void *)1) {
-			list_delete((struct list *)(pn->info));
+			list_delete_and_null((struct list **)(&pn->info));
 		}
 		pn->info = NULL;
 		route_unlock_node(pn); /* linklist or 1 deleted */
diff --git a/bgpd/rfapi/rfapi_vty.c b/bgpd/rfapi/rfapi_vty.c
index c6958237a..7bfc8882e 100644
--- a/bgpd/rfapi/rfapi_vty.c
+++ b/bgpd/rfapi/rfapi_vty.c
@@ -3274,7 +3274,7 @@ static int rfapiDeleteLocalPrefixesByRFD(struct rfapi_local_reg_delete_arg *cda,
 				}
 				list_delete_all_node(adb_delete_list);
 			}
-			list_delete(adb_delete_list);
+			list_delete_and_null(&adb_delete_list);
 		}
 
 
diff --git a/bgpd/rfapi/vnc_import_bgp.c b/bgpd/rfapi/vnc_import_bgp.c
index 117d4fbfd..4122ae5a9 100644
--- a/bgpd/rfapi/vnc_import_bgp.c
+++ b/bgpd/rfapi/vnc_import_bgp.c
@@ -2426,7 +2426,7 @@ void vnc_import_bgp_exterior_add_route_interior(
 			skiplist_delete(it->monitor_exterior_orphans,
 					bi_exterior, NULL);
 		}
-		list_delete(list_adopted);
+		list_delete_and_null(&list_adopted);
 	}
 }
 
diff --git a/bgpd/rfapi/vnc_zebra.c b/bgpd/rfapi/vnc_zebra.c
index 3fc6ddfe3..b8058cf1e 100644
--- a/bgpd/rfapi/vnc_zebra.c
+++ b/bgpd/rfapi/vnc_zebra.c
@@ -584,7 +584,7 @@ static void vnc_zebra_add_del_prefix(struct bgp *bgp,
 		nve_list_to_nh_array(rn->p.family, nves, &nexthop_count,
 				     &nh_ary, &nhp_ary);
 
-		list_delete(nves);
+		list_delete_and_null(&nves);
 
 		if (nexthop_count)
 			vnc_zebra_route_msg(&rn->p, nexthop_count, nhp_ary,
@@ -753,7 +753,7 @@ static void vnc_zebra_add_del_group_afi(struct bgp *bgp,
 		vnc_zlog_debug_verbose("%s: family: %d, nve count: %d",
 				       __func__, family, nexthop_count);
 
-		list_delete(nves);
+		list_delete_and_null(&nves);
 
 		if (nexthop_count) {
 			/*