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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2001,2007 Oracle. All rights reserved.
*
* $Id: os_uid.c,v 12.27 2007/05/17 15:15:46 bostic Exp $
*/
#include "db_config.h"
#include "db_int.h"
/*
* __os_unique_id --
* Return a unique 32-bit value.
*
* PUBLIC: void __os_unique_id __P((DB_ENV *, u_int32_t *));
*/
void
__os_unique_id(dbenv, idp)
DB_ENV *dbenv;
u_int32_t *idp;
{
db_timespec v;
pid_t pid;
u_int32_t id;
*idp = 0;
/*
* Our randomized value is comprised of our process ID, the current
* time of day and a stack address, all XOR'd together.
*/
__os_id(dbenv, &pid, NULL);
__os_gettime(dbenv, &v);
id = (u_int32_t)pid ^
(u_int32_t)v.tv_sec ^ (u_int32_t)v.tv_nsec ^ P_TO_UINT32(&pid);
/*
* We could try and find a reasonable random-number generator, but
* that's not all that easy to do. Seed and use srand()/rand(), if
* we can find them.
*/
if (DB_GLOBAL(uid_init) == 0) {
DB_GLOBAL(uid_init) = 1;
srand((u_int)id);
}
id ^= (u_int)rand();
*idp = id;
}
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