ubusd_id.c

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/*
 * Copyright (C) 2011 Felix Fietkau <nbd@openwrt.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <libubox/avl-cmp.h>
 
#include "ubusmsg.h"
#include "ubusd_id.h"
 
static int random_fd = -1;
 
static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
{
        const uint32_t *id1 = k1, *id2 = k2;
 
        if (*id1 < *id2)
                return -1;
        else
                return *id1 > *id2;
}
 
void ubus_init_string_tree(struct avl_tree *tree, bool dup)
{
        avl_init(tree, avl_strcmp, dup, NULL);
}
 
void ubus_init_id_tree(struct avl_tree *tree)
{
        if (random_fd < 0) {
                random_fd = open("/dev/urandom", O_RDONLY);
                if (random_fd < 0) {
                        perror("open");
                        exit(1);
                }
        }
 
        avl_init(tree, ubus_cmp_id, false, NULL);
}
 
bool ubus_alloc_id(struct avl_tree *tree, struct ubus_id *id, uint32_t val)
{
        id->avl.key = &id->id;
        if (val) {
                id->id = val;
                return avl_insert(tree, &id->avl) == 0;
        }
 
        do {
                if (read(random_fd, &id->id, sizeof(id->id)) != sizeof(id->id))
                        return false;
 
                if (id->id < UBUS_SYSTEM_OBJECT_MAX)
                        continue;
        } while (avl_insert(tree, &id->avl) != 0);
 
        return true;
}