Update on_load handling during boot

Introduce a transient worker that is started by kernel:init
and that only calls init:run_on_load_handlers(), which will
run all so far postponed (after code load) on_load handlers.
The worker exits immediately after that.

This on_load worker is run after code_server and standard_error,
which should provide enough fundamentals for the on_load handlers
themselves.

The need for explicitly calling on_load handlers from e.g user_drv
and the SSL distribution inet_tls_dist should vanish.

Therefore init:run_on_load_handlers/1 should be removed, but
to avoid bootstrap problems that can wait to a later commit.

lib/kernel/src/kernel.erl

@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1996-2022. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2023. All Rights Reserved.
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -58,14 +58,19 @@ config_change(Changed, New, Removed) ->
 %%%              | kernel_sup (A)|
 %%%	          ---------------
 %%%                      |
-%%%        -------------------------------
-%%%       |              |                |
-%%%  <std services> -------------   -------------
-%%%   (file,code,  | erl_dist (A)| | safe_sup (1)|
-%%%    rpc, ...)    -------------   -------------
-%%%		          |               |
-%%%                  (net_kernel,  (disk_log, pg,
-%%%          	      auth, ...)     ...)
+%%%        ------------------------------------------
+%%%       |             |          |        |        |
+%%%  <std services>     |    -------------  |  -------------
+%%%   (code, [stderr],  |   | erl_dist (A)| | | safe_sup (1)|
+%%%    ...)             |    -------------  |  -------------
+%%%		        |          |        |        |
+%%%                <on_load>  ([net_sup],   | (disk_log, pg,
+%%%               (transient)  rpc, global, |  ...)
+%%%                            ...)         |
+%%%                                         |
+%%%                                   <more services>
+%%%                                    (file, peer, [user],
+%%%                                     [logger], ...)
 %%%
 %%% The rectangular boxes are supervisors.  All supervisors except
 %%% for kernel_safe_sup terminates the entire erlang node if any of
@@ -118,6 +123,15 @@ init([]) ->
                  type => supervisor,
                  modules => [standard_error]},
 
+    OnLoad = #{id => on_load,
+               start =>
+                   {proc_lib, start_link,
+                    [?MODULE, ?FUNCTION_NAME, [on_load]]},
+               restart => transient,
+               shutdown => 2000,
+               type => worker,
+               modules => [?MODULE]},
+
     User = #{id => user,
              start => {user_sup, start, []},
              restart => temporary,
@@ -148,7 +162,8 @@ init([]) ->
     case init:get_argument(mode) of
         {ok, [["minimal"]|_]} ->
             {ok, {SupFlags,
-                  [Code, File, StdError] ++ Peer ++
+                  [Code, StdError, OnLoad] ++
+                      [File | Peer] ++
                       [User, LoggerSup, Config, RefC, SafeSup]}};
         _ ->
             DistChildren =
@@ -175,11 +190,18 @@ init([]) ->
             CompileServer = start_compile_server(),
 
             {ok, {SupFlags,
-                  [Code, InetDb | DistChildren] ++
-                      [File, SigSrv, StdError] ++ Peer ++
-                      [User, Config, RefC, SafeSup, LoggerSup] ++
+                  [Code, StdError, OnLoad, InetDb | DistChildren] ++
+                      [File, SigSrv | Peer] ++
+                      [User, LoggerSup, Config, RefC, SafeSup] ++
                       Timer ++ CompileServer}}
     end;
+init(on_load) ->
+    %% Run the on_load handlers for all modules that have been
+    %% loaded so far. Running them at this point means that
+    %% on_load handlers can safely call some essential kernel processes,
+    %% in particular call code:priv_dir/1 or code:lib_dir/1.
+    init:run_on_load_handlers(),
+    proc_lib:init_ack({ok, self()});
 init(safe) ->
     SupFlags = #{strategy => one_for_one,
                  intensity => 4,
@@ -189,12 +211,6 @@ init(safe) ->
     DiskLog = start_disk_log(),
     Pg = start_pg(),
 
-    %% Run the on_load handlers for all modules that have been
-    %% loaded so far. Running them at this point means that
-    %% on_load handlers can safely call kernel processes
-    %% (and in particular call code:priv_dir/1 or code:lib_dir/1).
-    init:run_on_load_handlers(),
-
     {ok, {SupFlags, Boot ++ DiskLog ++ Pg}}.
 
 start_distribution() ->

lib/kernel/src/user_drv.erl

@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1996-2021. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2023. All Rights Reserved.
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -139,9 +139,6 @@ callback_mode() -> state_functions.
 -spec init(arguments()) -> gen_statem:init_result(init).
 init(Args) ->
     process_flag(trap_exit, true),
-    %% When running in embedded mode we need to call prim_tty:on_load manually here
-    %% as the automatic call happens after user is started.
-    ok = init:run_on_load_handlers([prim_tty]),
 
     IsTTY = prim_tty:isatty(stdin) =:= true andalso prim_tty:isatty(stdout) =:= true,
     StartShell = maps:get(initial_shell, Args, undefined) =/= noshell,

lib/ssl/test/ssl_dist_SUITE.erl

@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2007-2022. All Rights Reserved.
+%% Copyright Ericsson AB 2007-2023. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -1102,6 +1102,7 @@ add_ssl_opts_config(Config) ->
 	{ok, _} = file:read_file_info(KrnlDir),
 	SSL_VSN = get_app_vsn(ssl),
 	VSN_CRYPTO = get_app_vsn(crypto),
+	VSN_ASN1 = get_app_vsn(asn1),
 	VSN_PKEY = get_app_vsn(public_key),
 
 	SslDir = filename:join([LibDir, "ssl-" ++ SSL_VSN]),
@@ -1116,6 +1117,7 @@ add_ssl_opts_config(Config) ->
 		  " [{kernel, \"~s\"},~n"
 		  "  {stdlib, \"~s\"},~n"
 		  "  {crypto, \"~s\"},~n"
+		  "  {asn1, \"~s\"},~n"
 		  "  {public_key, \"~s\"},~n"
 		  "  {ssl, \"~s\"}]}.~n",
 		  [case catch erlang:system_info(otp_release) of
@@ -1126,13 +1128,23 @@ add_ssl_opts_config(Config) ->
 		   KRNL_VSN,
 		   STDL_VSN,
 		   VSN_CRYPTO,
+                   VSN_ASN1,
 		   VSN_PKEY,
 		   SSL_VSN]),
 	ok = file:close(RelFile),
-	ok = systools:make_script(Script, []),
+        ct:log("Bootscript: ~p", [Script]),
+	case systools:make_script(Script, []) of
+            ok ->
+                ok;
+            NotOk ->
+                ct:log("Bootscript problem: ~p", [NotOk]),
+                erlang:error(NotOk)
+        end,
 	[{app_opts, "-boot " ++ Script} | Config]
     catch
-	_:_ ->
+	Class : Reason : Stacktrace ->
+            ct:log("Exception while generating bootscript:~n~p",
+                   [{Class, Reason, Stacktrace}]),
 	    [{app_opts, "-pa \"" ++ filename:dirname(code:which(ssl))++"\""}
 	     | add_comment_config(
 		 "Bootscript wasn't used since the test wasn't run on an "