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/*-
* Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com>
* 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/kernel.h>
#include <sys/module.h>
#include <sys/selinfo.h>
#include <sys/systm.h>
#include <dev/random/random_adaptors.h>
#include <dev/random/randomdev.h>
static int random_example_entropy_control;
#define RNG_NAME "example"
static int random_example_read(void *, int);
static void random_example_init(void);
struct random_adaptor random_example = {
.ident = "Example RNG",
.init = random_example_init,
.deinit = (random_deinit_func_t *)random_null_func,
.read = random_example_read,
.write = (random_write_func_t *)random_null_func,
.reseed = (random_reseed_func_t *)random_null_func,
.seeded = 1,
};
static void
random_example_init(void)
{
/*
* Init() is called only if this RNG was chosen to plugin in to
* random(4). In which case, we should no longer use this adaptor as
* an entropy source.
*/
random_example_entropy_control = 1;
}
/*
* Used under the license provided @ http://xkcd.com/221/
* http://creativecommons.org/licenses/by-nc/2.5/
*/
static u_char
getRandomNumber(void)
{
return 4; /* chosen by fair dice roll, guaranteed to be random */
}
static int
random_example_read(void *buf, int c)
{
u_char *b;
int count;
b = buf;
for (count = 0; count < c; count++) {
b[count] = getRandomNumber();
}
printf("returning %d bytes of pure randomness\n", c);
return (c);
}
static int
random_example_modevent(module_t mod, int type, void *unused)
{
switch (type) {
case MOD_LOAD:
/* start off by using this as an entropy source */
random_adaptor_use_as_entropy(RNG_NAME, &random_example,
&random_example_entropy_control);
random_adaptor_register(RNG_NAME, &random_example);
EVENTHANDLER_INVOKE(random_adaptor_attach, &random_example);
return (0);
}
return (EINVAL);
}
RANDOM_ADAPTOR_MODULE(random_example, random_example_modevent, 1);
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