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
  19 #include "ubusmsg.h"
  20 #include "ubusd_id.h"
  21
  22 static int random_fd = -1;
  23
  24 static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
  25 {
  26         const uint32_t *id1 = k1, *id2 = k2;
  27
  28         if (*id1 < *id2)
  29                 return -1;
  30         else
  31                 return *id1 > *id2;
  32 }
  33
  34 static int ubus_cmp_str(const void *k1, const void *k2, void *ptr)
  35 {
  36         return strcmp(k1, k2);
  37 }
  38
  39 void ubus_init_string_tree(struct avl_tree *tree, bool dup)
  40 {
  41         avl_init(tree, ubus_cmp_str, dup, NULL);
  42 }
  43
  44 void ubus_init_id_tree(struct avl_tree *tree)
  45 {
  46         if (random_fd < 0) {
  47                 random_fd = open("/dev/urandom", O_RDONLY);
  48                 if (random_fd < 0) {
  49                         perror("open");
  50                         exit(1);
  51                 }
  52         }
  53
  54         avl_init(tree, ubus_cmp_id, false, NULL);
  55 }
  56
  57 bool ubus_alloc_id(struct avl_tree *tree, struct ubus_id *id, uint32_t val)
  58 {
  59         id->avl.key = &id->id;
  60         if (val) {
  61                 id->id = val;
  62                 return avl_insert(tree, &id->avl) == 0;
  63         }
  64
  65         do {
  66                 if (read(random_fd, &id->id, sizeof(id->id)) != sizeof(id->id))
  67                         return false;
  68
  69                 if (id->id < UBUS_SYSTEM_OBJECT_MAX)
  70                         continue;
  71         } while (avl_insert(tree, &id->avl) != 0);
  72
  73         return true;
  74 }
  75