gecko-dev/tools/reorder/rseed.c

/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is ``rseed''
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corp.  Portions created by the Initial Developer are
 * Copyright (C) 2001 the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Chris Waterson <waterson@netscape.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
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 * decision by deleting the provisions above and replace them with the notice
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 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/*

  A program that reads /dev/random to produce a seed for srand(3).

 */

#include <stdio.h>
#include <fcntl.h>

int
main(int argc, char *argv[])
{
    int fd, ok, seed = 0;

    fd = open("/dev/random", O_RDONLY);
    if (fd < 0) {
        perror("/dev/random");
        return 1;
    }

    ok = read(fd, &seed, sizeof seed);
    if (ok > 0)
        printf("%d\n", seed);
    else
        perror("/dev/random");

    close(fd);
    return 0;
}