Remove short-lived idea; thread to harvest (eg) RDRAND enropy into the usual harvest queues. It was a nifty idea, but too heavyweight.

Submitted by:	Arthur Mesh <arthurmesh@gmail.com>

3 files changed, 1 insertions, 92 deletions

diff --git a/share/examples/kld/random_adaptor/random_adaptor_example.c b/share/examples/kld/random_adaptor/random_adaptor_example.c
index f94a7c2..c0ab10a 100644
--- a/share/examples/kld/random_adaptor/random_adaptor_example.c
+++ b/share/examples/kld/random_adaptor/random_adaptor_example.c
@@ -37,16 +37,13 @@ __FBSDID("$FreeBSD$");
 #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,
+	.init = (random_init_func_t *)random_null_func,
 	.deinit = (random_deinit_func_t *)random_null_func,
 	.read = random_example_read,
 	.write = (random_write_func_t *)random_null_func,
@@ -54,18 +51,6 @@ struct random_adaptor random_example = {
 	.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/
@@ -98,9 +83,6 @@ 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);
diff --git a/sys/dev/random/random_adaptors.c b/sys/dev/random/random_adaptors.c
index b017993..f6a21f6 100644
--- a/sys/dev/random/random_adaptors.c
+++ b/sys/dev/random/random_adaptors.c
@@ -55,11 +55,6 @@ static struct sysctl_ctx_list random_clist;
 
 MALLOC_DEFINE(M_RANDOM_ADAPTORS, "random_adaptors", "Random adaptors buffers");
 
-struct entropy_thread_ctx {
-	 struct random_adaptor   *adaptor;
-	 int			 *control;
-};
-
 int
 random_adaptor_register(const char *name, struct random_adaptor *rsp)
 {
@@ -186,72 +181,6 @@ random_adaptor_choose(struct random_adaptor **adaptor)
 }
 
 static void
-random_proc(void *arg)
-{
-	struct entropy_thread_ctx *ctx;
-	u_char randomness[HARVESTSIZE];
-	int i;
-
-	ctx = (struct entropy_thread_ctx *)arg;
-
-	/* Sanity check. */
-	if (ctx->adaptor == NULL || ctx->adaptor->read == NULL)
-		return;
-
-	for (; *ctx->control == 0;) {
-		i = ctx->adaptor->read(randomness, sizeof(randomness));
-
-		if (i > 0)
-			/* Be very conservative with entropy estimation here. */
-			random_harvest(randomness, i, 0, 0, RANDOM_PURE);
-
-		/* Wake up every 10 secs. */
-		tsleep_sbt(ctx->adaptor, PWAIT | PCATCH, "-", SBT_1M / 6, 0, 0);
-	}
-
-	printf("<%s> entropy source is exiting\n", ctx->adaptor->ident);
-	free(ctx, M_RANDOM_ADAPTORS);
-	kproc_exit(0);
-}
-
-/*
- * Use RNG's output as an entropy source for another RNG. i.e.:
- * +--------+          +--------+
- * | Intel  |          | Yarrow |
- * | RDRAND +--------->|        |
- * +--------+          +--------+
- * Very useful for seeding software RNGs with output of
- * Hardware RNGs like Intel's RdRand and VIA's Padlock.
- *
- * Returns a handle to the newly created kernel process.
- */
-void *
-random_adaptor_use_as_entropy(const char *id, struct random_adaptor *adaptor,
-    int *control)
-{
-	int error;
-	struct proc *random_chain_proc;
-	struct entropy_thread_ctx *ctx;
-
-	KASSERT(adaptor != NULL, ("can't obtain randomness"));
-	KASSERT(control != NULL, ("can't control entropy process"));
-
-	ctx = malloc(sizeof(struct entropy_thread_ctx), M_RANDOM_ADAPTORS,
-	    M_WAITOK);
-
-	ctx->control = control;
-	ctx->adaptor = adaptor;
-
-	/* Start the thread */
-	error = kproc_create(random_proc, ctx, &random_chain_proc, RFHIGHPID,
-	    0, "%s_entropy", id);
-	if (error != 0)
-		panic("Cannot create rng chaining thread");
-
-	return random_chain_proc;
-}
-
-static void
 random_adaptors_deinit(void *unused)
 {
 
diff --git a/sys/dev/random/random_adaptors.h b/sys/dev/random/random_adaptors.h
index b3038e7..98f8c2e 100644
--- a/sys/dev/random/random_adaptors.h
+++ b/sys/dev/random/random_adaptors.h
@@ -40,8 +40,6 @@ struct random_adaptors {
 struct random_adaptor *random_adaptor_get(const char *);
 int random_adaptor_register(const char *, struct random_adaptor *);
 void random_adaptor_choose(struct random_adaptor **);
-void *random_adaptor_use_as_entropy(const char *, struct random_adaptor *,
-    int *);
 
 /*
  * random_adaptor's should be registered prior to