source: vendor/current/lib/util/genrand.c

/*
   Unix SMB/CIFS implementation.

   Functions to create reasonable random numbers for crypto use.

   Copyright (C) Jeremy Allison 2001

   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "replace.h"
#include "system/filesys.h"
#include "lib/util/genrand.h"
#include "sys_rw_data.h"
#include "lib/util/blocking.h"

static int urand_fd = -1;

static void open_urandom(void)
{
        if (urand_fd != -1) {
                return;
        }
        urand_fd = open( "/dev/urandom", O_RDONLY,0);
        if (urand_fd == -1) {
                abort();
        }
        smb_set_close_on_exec(urand_fd);
}

_PUBLIC_ void generate_random_buffer(uint8_t *out, int len)
{
        ssize_t rw_ret;

        open_urandom();

        rw_ret = read_data(urand_fd, out, len);
        if (rw_ret != len) {
                abort();
        }
}

/*
 * Keep generate_secret_buffer in case we ever want to do something
 * different
 */
_PUBLIC_ void generate_secret_buffer(uint8_t *out, int len)
{
        generate_random_buffer(out, len);
}