serval-dna/srandomdev.c

/* 
Serval Distributed Numbering Architecture (DNA)
Copyright (C) 2010 Paul Gardner-Stephen 

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

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.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

/*-
 * Copyright (c) 2006 Verdens Gang AS
 * Copyright (c) 2006-2008 Linpro AS
 * All rights reserved.
 *
 * Author: Dag-Erling Sm<EFBFBD>\u017ergrav <des@linpro.no>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id$
 */

#ifndef HAVE_SRANDOMDEV

#ifndef WIN32
#include <sys/time.h>
#include <unistd.h>
#endif

#include "serval.h"
#include <fcntl.h>
#include <stdlib.h>
#include <time.h>

void
srandomdev(void)
{
        struct timeval tv;
        unsigned int seed;
#ifndef WIN32
        FILE *fd;

        fd = fopen("/dev/urandom", "r");
        if (fd >= 0) {
                fread(&seed, sizeof seed, 1, fd);
                fclose(fd);
        } else 
#endif
		{

                gettimeofday(&tv, NULL);
                /* NOTE: intentional use of uninitialized variable */
                seed ^= (getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec;
        }
        srandom(seed);
}
#endif