lib/qobj.c

   1 /*
   2  * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
   3  *
   4  * This file is part of Quagga
   5  *
   6  * Quagga is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2, or (at your option) any
   9  * later version.
  10  *
  11  * Quagga is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <zebra.h>
  22
  23 #include "thread.h"
  24 #include "memory.h"
  25 #include "hash.h"
  26 #include "log.h"
  27 #include "qobj.h"
  28
  29 static pthread_rwlock_t nodes_lock;
  30 static struct hash *nodes = NULL;
  31
  32 static unsigned int qobj_key(void *data)
  33 {
  34         struct qobj_node *node = data;
  35         return (unsigned int)node->nid;
  36 }
  37
  38 static int qobj_cmp(const void *a, const void *b)
  39 {
  40         const struct qobj_node *na = a, *nb = b;
  41         return na->nid == nb->nid;
  42 }
  43
  44 void qobj_reg(struct qobj_node *node, struct qobj_nodetype *type)
  45 {
  46         node->type = type;
  47         pthread_rwlock_wrlock(&nodes_lock);
  48         do {
  49                 node->nid = (uint64_t)random();
  50                 node->nid ^= (uint64_t)random() << 32;
  51         } while (!node->nid
  52                  || hash_get(nodes, node, hash_alloc_intern) != node);
  53         pthread_rwlock_unlock(&nodes_lock);
  54 }
  55
  56 void qobj_unreg(struct qobj_node *node)
  57 {
  58         pthread_rwlock_wrlock(&nodes_lock);
  59         hash_release(nodes, node);
  60         pthread_rwlock_unlock(&nodes_lock);
  61 }
  62
  63 struct qobj_node *qobj_get(uint64_t id)
  64 {
  65         struct qobj_node dummy = {.nid = id}, *rv;
  66         pthread_rwlock_rdlock(&nodes_lock);
  67         rv = hash_lookup(nodes, &dummy);
  68         pthread_rwlock_unlock(&nodes_lock);
  69         return rv;
  70 }
  71
  72 void *qobj_get_typed(uint64_t id, struct qobj_nodetype *type)
  73 {
  74         struct qobj_node dummy = {.nid = id};
  75         struct qobj_node *node;
  76         void *rv;
  77
  78         pthread_rwlock_rdlock(&nodes_lock);
  79         node = hash_lookup(nodes, &dummy);
  80
  81         /* note: we explicitly hold the lock until after we have checked the
  82          * type.
  83          * if the caller holds a lock that for example prevents the deletion of
  84          * route-maps, we can still race against a delete of something that
  85          * isn't
  86          * a route-map. */
  87         if (!node || node->type != type)
  88                 rv = NULL;
  89         else
  90                 rv = (char *)node - node->type->node_member_offset;
  91
  92         pthread_rwlock_unlock(&nodes_lock);
  93         return rv;
  94 }
  95
  96 void qobj_init(void)
  97 {
  98         if (!nodes) {
  99                 pthread_rwlock_init(&nodes_lock, NULL);
 100                 nodes = hash_create(qobj_key, qobj_cmp, NULL);
 101         }
 102 }
 103
 104 void qobj_finish(void)
 105 {
 106         hash_clean(nodes, NULL);
 107         hash_free(nodes);
 108         nodes = NULL;
 109         pthread_rwlock_destroy(&nodes_lock);
 110 }