ubusd_id.c

   1 /*
   2  * Copyright (C) 2011 Felix Fietkau <nbd@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <unistd.h>
  17 #include <fcntl.h>
  18 #include <libubox/avl-cmp.h>
  19
  20 #include "ubusmsg.h"
  21 #include "ubusd_id.h"
  22
  23 static int random_fd = -1;
  24
  25 static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
  26 {
  27         const uint32_t *id1 = k1, *id2 = k2;
  28
  29         if (*id1 < *id2)
  30                 return -1;
  31         else
  32                 return *id1 > *id2;
  33 }
  34
  35 void ubus_init_string_tree(struct avl_tree *tree, bool dup)
  36 {
  37         avl_init(tree, avl_strcmp, dup, NULL);
  38 }
  39
  40 void ubus_init_id_tree(struct avl_tree *tree)
  41 {
  42         if (random_fd < 0) {
  43                 random_fd = open("/dev/urandom", O_RDONLY);
  44                 if (random_fd < 0) {
  45                         perror("open");
  46                         exit(1);
  47                 }
  48         }
  49
  50         avl_init(tree, ubus_cmp_id, false, NULL);
  51 }
  52
  53 bool ubus_alloc_id(struct avl_tree *tree, struct ubus_id *id, uint32_t val)
  54 {
  55         id->avl.key = &id->id;
  56         if (val) {
  57                 id->id = val;
  58                 return avl_insert(tree, &id->avl) == 0;
  59         }
  60
  61         do {
  62                 if (read(random_fd, &id->id, sizeof(id->id)) != sizeof(id->id))
  63                         return false;
  64
  65                 if (id->id < UBUS_SYSTEM_OBJECT_MAX)
  66                         continue;
  67         } while (avl_insert(tree, &id->avl) != 0);
  68
  69         return true;
  70 }
  71