Merge branch 'bjorn/clearer-startup-crashes/OTP-13294'

* bjorn/clearer-startup-crashes/OTP-13294:
  Make distribution failures during start-up easier to read
  net_kernel: Separate exports into documented and non-documented groups
  erl_distribution: Simplify start_link/0 and friends
  Reorder and comment API functions
  Clean up splitting of node names

1 files changed, 43 insertions, 47 deletions

diff --git a/lib/kernel/src/erl_distribution.erl b/lib/kernel/src/erl_distribution.erl
index 99db7a8bf0..559e2a853b 100644
--- a/lib/kernel/src/erl_distribution.erl
+++ b/lib/kernel/src/erl_distribution.erl
@@ -21,20 +21,47 @@
 
 -behaviour(supervisor).
 
--export([start_link/0,start_link/1,init/1,start/1,stop/0]).
+-export([start_link/0,start_link/2,init/1,start/1,stop/0]).
 
 -define(DBG,erlang:display([?MODULE,?LINE])).
 
+%% Called during system start-up.
+
 start_link() ->
-    case catch start_p() of
-	{ok,Args} ->
-	    start_link(Args);
-	_ ->
-	    ignore
+    do_start_link([{sname,shortnames},{name,longnames}]).
+
+%% Called from net_kernel:start/1 to start distribution after the
+%% system has already started.
+
+start(Args) ->
+    C = {net_sup_dynamic, {?MODULE,start_link,[Args,false]}, permanent,
+	 1000, supervisor, [erl_distribution]},
+    supervisor:start_child(kernel_sup, C).
+
+%% Stop distribution.
+
+stop() ->
+    case supervisor:terminate_child(kernel_sup, net_sup_dynamic) of
+	ok ->
+	    supervisor:delete_child(kernel_sup, net_sup_dynamic);
+	Error ->
+	    case whereis(net_sup) of
+		Pid when is_pid(Pid) ->
+		    %% Dist. started through -sname | -name flags
+		    {error, not_allowed};
+		_ ->
+		    Error
+	    end
     end.
 
-start_link(Args) ->
-    supervisor:start_link({local,net_sup},erl_distribution,Args).
+%%%
+%%% Internal helper functions.
+%%%
+
+%% Helper start function.
+
+start_link(Args, CleanHalt) ->
+    supervisor:start_link({local,net_sup}, ?MODULE, [Args,CleanHalt]).
 
 init(NetArgs) ->
     Epmd = 
@@ -47,31 +74,20 @@ init(NetArgs) ->
 		  permanent,2000,worker,[EpmdMod]}]
 	end,
     Auth = {auth,{auth,start_link,[]},permanent,2000,worker,[auth]},
-    Kernel = {net_kernel,{net_kernel,start_link,[NetArgs]},
+    Kernel = {net_kernel,{net_kernel,start_link,NetArgs},
 	      permanent,2000,worker,[net_kernel]},
     EarlySpecs = net_kernel:protocol_childspecs(),
     {ok,{{one_for_all,0,1}, EarlySpecs ++ Epmd ++ [Auth,Kernel]}}.
 
-start_p() ->
-    sname(),
-    lname(),
-    false.
-
-sname() ->
-    case init:get_argument(sname) of
+do_start_link([{Arg,Flag}|T]) ->
+    case init:get_argument(Arg) of
 	{ok,[[Name]]} ->
-	    throw({ok,[list_to_atom(Name),shortnames|ticktime()]});
+	    start_link([list_to_atom(Name),Flag|ticktime()], true);
 	_ ->
-	    false
-    end.
-
-lname() ->
-    case init:get_argument(name) of
-	{ok,[[Name]]} ->
-	    throw({ok,[list_to_atom(Name),longnames|ticktime()]});
-	_ ->
-	    false
-    end.
+	    do_start_link(T)
+    end;
+do_start_link([]) ->
+    ignore.
 
 ticktime() ->
     %% catch, in case the system was started with boot file start_old,
@@ -84,23 +100,3 @@ ticktime() ->
 	_ ->
 	    []
     end.
-
-start(Args) ->
-    C = {net_sup_dynamic, {erl_distribution, start_link, [Args]}, permanent,
-	 1000, supervisor, [erl_distribution]},
-    supervisor:start_child(kernel_sup, C).
-
-stop() ->
-    case supervisor:terminate_child(kernel_sup, net_sup_dynamic) of
-	ok ->
-	    supervisor:delete_child(kernel_sup, net_sup_dynamic);
-	Error ->
-	    case whereis(net_sup) of
-		Pid when is_pid(Pid) ->
-		    %% Dist. started through -sname | -name flags
-		    {error, not_allowed};
-		_ ->
-		    Error
-	    end
-    end.
-