Decouple yarrow from random(4) device.

* Make Yarrow an optional kernel component -- enabled by "YARROW_RNG" option.
  The files sha2.c, hash.c, randomdev_soft.c and yarrow.c comprise yarrow.

* random(4) device doesn't really depend on rijndael-*.  Yarrow, however, does.

* 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: obrien

1 files changed, 2 insertions, 4 deletions

diff --git a/sys/dev/random/randomdev.h b/sys/dev/random/randomdev.h
index deb6831..75b2c19 100644
--- a/sys/dev/random/randomdev.h
+++ b/sys/dev/random/randomdev.h
@@ -38,7 +38,7 @@ typedef void random_write_func_t(void *, int);
 typedef int random_poll_func_t(int, struct thread *);
 typedef void random_reseed_func_t(void);
 
-struct random_systat {
+struct random_adaptor {
 	struct selinfo		rsel;
 	const char		*ident;
 	int			seeded;
@@ -51,7 +51,5 @@ struct random_systat {
 	random_reseed_func_t	*reseed;
 };
 
-extern struct random_systat *random_systat;
-
-extern void random_ident_hardware(struct random_systat **);
+extern void random_ident_hardware(struct random_adaptor **);
 extern void random_null_func(void);