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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>
#ifdef __linux__
#include <sys/random.h>
/* Added in Linux 5.6; define it in case the libc headers are older. */
#ifndef GRND_INSECURE
#define GRND_INSECURE 0x0004
#endif
#endif
#include <libubox/avl-cmp.h>
#include "ubusmsg.h"
#include "ubusd_id.h"
#ifndef __linux__
static int random_fd = -1;
#endif
static ssize_t read_random(void *buf, size_t len)
{
#ifdef __linux__
/*
* IDs only need to be hard to guess, not crypto-strong.
* GRND_INSECURE returns bytes without blocking on the CRNG, so
* ubusd does not stall boot on boards whose pool seeds late.
*/
return getrandom(buf, len, GRND_INSECURE);
#else
if (random_fd < 0) {
random_fd = open("/dev/urandom", O_RDONLY);
if (random_fd < 0) {
perror("open /dev/urandom");
return -1;
}
}
return read(random_fd, buf, len);
#endif
}
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)
{
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 {
do {
if (read_random(&id->id, sizeof(id->id)) != sizeof(id->id))
return false;
} while (id->id < UBUS_SYSTEM_OBJECT_MAX);
} while (avl_insert(tree, &id->avl) != 0);
return true;
}
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