/*      $NetBSD: hyperentropy.c,v 1.17 2020/04/30 03:41:20 riastradh Exp $      */

/*
* Copyright (c) 2014 Antti Kantee.  All Rights Reserved.
*
* 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 ``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 THE 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.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: hyperentropy.c,v 1.17 2020/04/30 03:41:20 riastradh Exp $");

#include <sys/param.h>
#include <sys/kmem.h>
#include <sys/rndsource.h>

#include <rump-sys/kern.h>

#include <rump/rumpuser.h>

static krndsource_t rndsrc;

static void
feedrandom(size_t bytes, void *cookie __unused)
{
       uint8_t *rnddata;
       size_t n, nread;

       rnddata = kmem_intr_alloc(bytes, KM_SLEEP);
       n = 0;
       while (n < bytes) {
               if (rumpuser_getrandom(rnddata + n, bytes - n,
                       RUMPUSER_RANDOM_HARD|RUMPUSER_RANDOM_NOWAIT, &nread)
                   != 0)
                       break;
               n += MIN(nread, bytes - n);
       }
       if (n) {
               rnd_add_data_sync(&rndsrc, rnddata, n, NBBY*n);
       }
       kmem_intr_free(rnddata, bytes);
}

void
rump_hyperentropy_init(void)
{

       rndsource_setcb(&rndsrc, &feedrandom, NULL);
       rnd_attach_source(&rndsrc, "rump_hyperent", RND_TYPE_VM,
           RND_FLAG_COLLECT_VALUE|RND_FLAG_HASCB);
}