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 #include "jhash.h"
  29
  30 static pthread_rwlock_t nodes_lock;
  31 static struct hash *nodes = NULL;
  32
  33 static unsigned int qobj_key(void *data)
  34 {
  35         struct qobj_node *node = data;
  36         return (unsigned int)node->nid;
  37 }
  38
  39 static bool qobj_cmp(const void *a, const void *b)
  40 {
  41         const struct qobj_node *na = a, *nb = b;
  42         return na->nid == nb->nid;
  43 }
  44
  45 void qobj_reg(struct qobj_node *node, struct qobj_nodetype *type)
  46 {
  47         node->type = type;
  48         pthread_rwlock_wrlock(&nodes_lock);
  49         do {
  50                 node->nid = (uint64_t)random();
  51                 node->nid ^= (uint64_t)random() << 32;
  52         } while (!node->nid
  53                  || hash_get(nodes, node, hash_alloc_intern) != node);
  54         pthread_rwlock_unlock(&nodes_lock);
  55 }
  56
  57 void qobj_unreg(struct qobj_node *node)
  58 {
  59         pthread_rwlock_wrlock(&nodes_lock);
  60         hash_release(nodes, node);
  61         pthread_rwlock_unlock(&nodes_lock);
  62 }
  63
  64 struct qobj_node *qobj_get(uint64_t id)
  65 {
  66         struct qobj_node dummy = {.nid = id}, *rv;
  67         pthread_rwlock_rdlock(&nodes_lock);
  68         rv = hash_lookup(nodes, &dummy);
  69         pthread_rwlock_unlock(&nodes_lock);
  70         return rv;
  71 }
  72
  73 void *qobj_get_typed(uint64_t id, struct qobj_nodetype *type)
  74 {
  75         struct qobj_node dummy = {.nid = id};
  76         struct qobj_node *node;
  77         void *rv;
  78
  79         pthread_rwlock_rdlock(&nodes_lock);
  80         node = hash_lookup(nodes, &dummy);
  81
  82         /* note: we explicitly hold the lock until after we have checked the
  83          * type.
  84          * if the caller holds a lock that for example prevents the deletion of
  85          * route-maps, we can still race against a delete of something that
  86          * isn't
  87          * a route-map. */
  88         if (!node || node->type != type)
  89                 rv = NULL;
  90         else
  91                 rv = (char *)node - node->type->node_member_offset;
  92
  93         pthread_rwlock_unlock(&nodes_lock);
  94         return rv;
  95 }
  96
  97 void qobj_init(void)
  98 {
  99         if (!nodes) {
 100                 pthread_rwlock_init(&nodes_lock, NULL);
 101                 nodes = hash_create_size(16, qobj_key, qobj_cmp, "QOBJ Hash");
 102         }
 103 }
 104
 105 void qobj_finish(void)
 106 {
 107         hash_clean(nodes, NULL);
 108         hash_free(nodes);
 109         nodes = NULL;
 110         pthread_rwlock_destroy(&nodes_lock);
 111 }