freebsd-nq/sys/dev/random/random_adaptors.c
David E. O'Brien 5711939b63 * Add random_adaptors.[ch] which is basically a store of random_adaptor's.
random_adaptor is basically an adapter that plugs in to random(4).
  random_adaptor can only be plugged in to random(4) very early in bootup.
  Unplugging random_adaptor from random(4) is not supported, and is probably a
  bad idea anyway, due to potential loss of entropy pools.
  We currently have 3 random_adaptors:
  + yarrow
  + rdrand (ivy.c)
  + nehemeiah

* Remove platform dependent logic from probe.c, and move it into
  corresponding registration routines of each random_adaptor provider.
  probe.c doesn't do anything other than picking a specific random_adaptor
  from a list of registered ones.

* If the kernel doesn't have any random_adaptor adapters present then the
  creation of /dev/random is postponed until next random_adaptor is kldload'ed.

* Fix randomdev_soft.c to refer to its own random_adaptor, instead of a
  system wide one.

Submitted by: arthurmesh@gmail.com, obrien
Obtained from: Juniper Networks
Reviewed by: so (des)
2013-08-09 15:31:50 +00:00

139 lines
3.8 KiB
C

/*-
* Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com>
* Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
* 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/param.h>
__FBSDID("$FreeBSD$");
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/selinfo.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/libkern.h>
#include <dev/random/random_adaptors.h>
#include <dev/random/randomdev.h>
LIST_HEAD(adaptors_head, random_adaptors);
static struct adaptors_head adaptors = LIST_HEAD_INITIALIZER(adaptors);
static struct sx adaptors_lock; /* need a sleepable lock */
/* List for the dynamic sysctls */
static struct sysctl_ctx_list random_clist;
MALLOC_DEFINE(M_RANDOM_ADAPTORS, "random_adaptors", "Random adaptors buffers");
int
random_adaptor_register(const char *name, struct random_adaptor *rsp)
{
struct random_adaptors *rpp;
KASSERT(name != NULL && rsp != NULL, ("invalid input to %s", __func__));
rpp = malloc(sizeof(struct random_adaptors), M_RANDOM_ADAPTORS, M_WAITOK);
rpp->name = name;
rpp->rsp = rsp;
sx_xlock(&adaptors_lock);
LIST_INSERT_HEAD(&adaptors, rpp, entries);
sx_xunlock(&adaptors_lock);
return (0);
}
struct random_adaptor *
random_adaptor_get(const char *name)
{
struct random_adaptors *rpp;
struct random_adaptor *rsp;
rsp = NULL;
sx_slock(&adaptors_lock);
LIST_FOREACH(rpp, &adaptors, entries)
if (strcmp(rpp->name, name) == 0)
rsp = rpp->rsp;
sx_sunlock(&adaptors_lock);
return (rsp);
}
static void
random_adaptors_deinit(void *unused)
{
sx_destroy(&adaptors_lock);
sysctl_ctx_free(&random_clist);
}
static int
random_sysctl_adaptors_handler(SYSCTL_HANDLER_ARGS)
{
struct random_adaptors *rpp;
int error;
error = 0;
sx_slock(&adaptors_lock);
if (LIST_EMPTY(&adaptors))
error = SYSCTL_OUT(req, "", strlen(""));
LIST_FOREACH(rpp, &adaptors, entries) {
if (0 != SYSCTL_OUT(req, rpp->name, strlen(rpp->name)))
break;
}
sx_sunlock(&adaptors_lock);
return (error);
}
static void
random_adaptors_init(void *unused)
{
SYSCTL_PROC(_kern_random, OID_AUTO, adaptors,
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
NULL, 0, random_sysctl_adaptors_handler, "",
"Random Number Generator adaptors");
sx_init(&adaptors_lock, "random_adaptors");
}
SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Random Number Generator");
SYSINIT(random_adaptors, SI_SUB_DRIVERS, SI_ORDER_FIRST, random_adaptors_init,
NULL);
SYSUNINIT(random_adaptors, SI_SUB_DRIVERS, SI_ORDER_FIRST,
random_adaptors_deinit, NULL);