From 688cc6d190f708359b3880085665b84605cae44b Mon Sep 17 00:00:00 2001
From: Hannes Mehnert <hannes@mehnert.org>
Date: Wed, 8 Jan 2025 14:23:42 +0100
Subject: [PATCH] de-deprecate miou-unix

---
 rng/miou/mirage_crypto_rng_miou_unix.mli |  1 -
 rng/mirage_crypto_rng.mli                | 12 ++++++++++++
 rng/rng.ml                               |  5 ++++-
 tests/test_miou_entropy_collection.ml    |  6 +-----
 tests/test_miou_rng.ml                   |  6 +-----
 5 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/rng/miou/mirage_crypto_rng_miou_unix.mli b/rng/miou/mirage_crypto_rng_miou_unix.mli
index 2a025d5c..057afbc8 100644
--- a/rng/miou/mirage_crypto_rng_miou_unix.mli
+++ b/rng/miou/mirage_crypto_rng_miou_unix.mli
@@ -14,7 +14,6 @@ type rng
 (** Type of tasks seeding the RNG. *)
 
 val initialize : ?g:'a -> ?sleep:int64 -> 'a Mirage_crypto_rng.generator -> rng
-[@@deprecated "Use 'Mirage_crypto_rng_unix.use_default ()' instead."]
 (** [initialize ?g ?sleep (module Generator)] will allow the RNG to operate in a
     returned task. This task periodically launches sub-tasks that seed the
     engine (using [getrandom()], [getentropy()] or [BCryptGenRandom()] depending
diff --git a/rng/mirage_crypto_rng.mli b/rng/mirage_crypto_rng.mli
index ad7e9299..240c9379 100644
--- a/rng/mirage_crypto_rng.mli
+++ b/rng/mirage_crypto_rng.mli
@@ -30,6 +30,18 @@
     Fortuna and producing random numbers is not thread-safe} (it is on Miou_unix
     via Pfortuna).
 
+    Suitable entropy feeding of generators are provided by other libraries
+    {{!Mirage_crypto_rng_mirage}mirage-crypto-rng-mirage} (for MirageOS),
+    and {{!Mirage_crypto_rng_miou_unix}mirage-crypto-miou-unix} (for Miou_unix).
+
+    The intention is that "initialize" in the respective sub-library is called
+    once, which sets the default generator and registers entropy
+    harvesting asynchronous tasks. The semantics is that the entropy is always
+    fed to the {{!default_generator}default generator}, which is not necessarily
+    the one set by "initialize". The reasoning behind this is that the default
+    generator should be used in most setting, and that should be fed a constant
+    stream of entropy.
+
     The RNGs here are merely the deterministic part of a full random number
     generation suite. For proper operation, they need to be seeded with a
     high-quality entropy source.
diff --git a/rng/rng.ml b/rng/rng.ml
index c410d415..0c628bfc 100644
--- a/rng/rng.ml
+++ b/rng/rng.ml
@@ -15,7 +15,10 @@ let setup_rng =
    following:\
    \n  If you are using MirageOS, use the random device in config.ml: \
    `let main = Mirage.main \"Unikernel.Main\" (random @-> job)`, \
-   and `let () = register \"my_unikernel\" [main $ default_random]`."
+   and `let () = register \"my_unikernel\" [main $ default_random]`. \
+   \n  If you are using miou, execute \
+   `Mirage_crypto_rng_miou_unix.initialize (module Mirage_crypto_rng.Fortuna)` \
+   at startup."
 
 let () = Printexc.register_printer (function
     | Unseeded_generator ->
diff --git a/tests/test_miou_entropy_collection.ml b/tests/test_miou_entropy_collection.ml
index 45a7f20f..57ad3eab 100644
--- a/tests/test_miou_entropy_collection.ml
+++ b/tests/test_miou_entropy_collection.ml
@@ -20,11 +20,7 @@ end
 
 let () =
   Miou_unix.run @@ fun () ->
-  let rng =
-    begin[@alert "-deprecated"]
-      Mirage_crypto_rng_miou_unix.initialize (module Printing_rng)
-    end
-  in
+  let rng = Mirage_crypto_rng_miou_unix.initialize (module Printing_rng) in
   Format.printf "entropy sources: %a@,%!"
     (fun ppf -> List.iter (fun x ->
          Mirage_crypto_rng.Entropy.pp_source ppf x;
diff --git a/tests/test_miou_rng.ml b/tests/test_miou_rng.ml
index 852a3251..1cd5dcb8 100644
--- a/tests/test_miou_rng.ml
+++ b/tests/test_miou_rng.ml
@@ -1,9 +1,5 @@
 let () = Miou_unix.run @@ fun () ->
-  let rng =
-    begin[@alert "-deprecated"]
-      Mirage_crypto_rng_miou_unix.(initialize (module Pfortuna))
-    end
-  in
+  let rng = Mirage_crypto_rng_miou_unix.(initialize (module Pfortuna)) in
   let random_num = Mirage_crypto_rng.generate 32 in
   assert (String.length random_num = 32);
   Printf.printf "32 bit random number: %s\n%!" (Ohex.encode random_num);