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/*-
* Copyright (c) 2000-2004 Mark R V Murray
* 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
* in this position and unchanged.
* 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 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>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/queue.h>
#include <sys/random.h>
#include <sys/selinfo.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <machine/cpu.h>
#include <dev/random/randomdev_soft.h>
static int read_random_phony(void *, int);
/* Structure holding the desired entropy sources */
struct harvest_select harvest = { 1, 1, 1, 0 };
/* hold the address of the routine which is actually called if
* the randomdev is loaded
*/
static void (*reap_func)(u_int64_t, const void *, u_int, u_int, u_int,
enum esource) = NULL;
static int (*read_func)(void *, int) = read_random_phony;
/* Initialise the harvester at load time */
void
random_yarrow_init_harvester(void (*reaper)(u_int64_t, const void *, u_int,
u_int, u_int, enum esource), int (*reader)(void *, int))
{
reap_func = reaper;
read_func = reader;
}
/* Deinitialise the harvester at unload time */
void
random_yarrow_deinit_harvester(void)
{
reap_func = NULL;
read_func = read_random_phony;
}
/* Entropy harvesting routine. This is supposed to be fast; do
* not do anything slow in here!
* Implemented as in indirect call to allow non-inclusion of
* the entropy device.
*
* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle
* counters are built in, but on older hardware it will do a real time clock
* read which can be quite expensive.
*/
void
random_harvest(void *entropy, u_int count, u_int bits, u_int frac,
enum esource origin)
{
if (reap_func)
(*reap_func)(get_cyclecount(), entropy, count, bits, frac,
origin);
}
/* Userland-visible version of read_random */
int
read_random(void *buf, int count)
{
return ((*read_func)(buf, count));
}
/* If the entropy device is not loaded, make a token effort to
* provide _some_ kind of randomness. This should only be used
* inside other RNG's, like arc4random(9).
*/
static int
read_random_phony(void *buf, int count)
{
u_long randval;
int size, i;
/* srandom() is called in kern/init_main.c:proc0_post() */
/* Fill buf[] with random(9) output */
for (i = 0; i < count; i+= (int)sizeof(u_long)) {
randval = random();
size = MIN(count - i, sizeof(u_long));
memcpy(&((char *)buf)[i], &randval, (size_t)size);
}
return (count);
}
/* Helper routine to enable kthread_exit() to work while the module is
* being (or has been) unloaded.
* This routine is in this file because it is always linked into the kernel,
* and will thus never be unloaded. This is critical for unloadable modules
* that have threads.
*/
void
random_set_wakeup_exit(void *control)
{
wakeup(control);
kthread_exit(0);
/* NOTREACHED */
}
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