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

2 files changed, 122 insertions, 99 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.
-
diff --git a/lib/kernel/src/net_kernel.erl b/lib/kernel/src/net_kernel.erl
index 35a54f591e..a19c116388 100644
--- a/lib/kernel/src/net_kernel.erl
+++ b/lib/kernel/src/net_kernel.erl
@@ -53,18 +53,25 @@
 -define(tckr_dbg(X), ok).
 -endif.
 
-%% User Interface Exports
--export([start/1, start_link/1, stop/0,
-	 kernel_apply/3,
+%% Documented API functions.
+
+-export([allow/1,
+	 connect_node/1,
 	 monitor_nodes/1,
 	 monitor_nodes/2,
+	 start/1,
+	 stop/0]).
+
+%% Exports for internal use.
+
+-export([start_link/2,
+	 kernel_apply/3,
 	 longnames/0,
-	 allow/1,
 	 protocol_childspecs/0,
 	 epmd_module/0]).
 
 -export([connect/1, disconnect/1, hidden_connect/1, passive_cnct/1]).
--export([connect_node/1, hidden_connect_node/1]). %% explicit connect
+-export([hidden_connect_node/1]). %% explicit connect
 -export([set_net_ticktime/1, set_net_ticktime/2, get_net_ticktime/0]).
 
 -export([node_info/1, node_info/2, nodes_info/0,
@@ -73,7 +80,8 @@
 
 -export([publish_on_node/1, update_publish_nodes/1]).
 
-%% Internal Exports
+%% Internal exports for spawning processes.
+
 -export([do_spawn/3,
 	 spawn_func/6,
 	 ticker/2,
@@ -341,18 +349,18 @@ request(Req) ->
 start(Args) ->
     erl_distribution:start(Args).
 
-%% This is the main startup routine for net_kernel
-%% The defaults are longnames and a ticktime of 15 secs to the tcp_drv.
+%% This is the main startup routine for net_kernel (only for internal
+%% use by the Kernel application.
 
-start_link([Name]) ->
-    start_link([Name, longnames]);
+start_link([Name], CleanHalt) ->
+    start_link([Name, longnames], CleanHalt);
+start_link([Name, LongOrShortNames], CleanHalt) ->
+    start_link([Name, LongOrShortNames, 15000], CleanHalt);
 
-start_link([Name, LongOrShortNames]) ->
-    start_link([Name, LongOrShortNames, 15000]);
-
-start_link([Name, LongOrShortNames, Ticktime]) ->
-    case gen_server:start_link({local, net_kernel}, net_kernel,
-			       {Name, LongOrShortNames, Ticktime}, []) of
+start_link([Name, LongOrShortNames, Ticktime], CleanHalt) ->
+    Args = {Name, LongOrShortNames, Ticktime, CleanHalt},
+    case gen_server:start_link({local, net_kernel}, ?MODULE,
+			       Args, []) of
 	{ok, Pid} ->
 	    {ok, Pid};
 	{error, {already_started, Pid}} ->
@@ -361,12 +369,9 @@ start_link([Name, LongOrShortNames, Ticktime]) ->
 	    exit(nodistribution)
     end.
 
-%% auth:get_cookie should only be able to return an atom
-%% tuple cookies are unknowns
-
-init({Name, LongOrShortNames, TickT}) ->
+init({Name, LongOrShortNames, TickT, CleanHalt}) ->
     process_flag(trap_exit,true),
-    case init_node(Name, LongOrShortNames) of
+    case init_node(Name, LongOrShortNames, CleanHalt) of
 	{ok, Node, Listeners} ->
 	    process_flag(priority, max),
 	    Ticktime = to_integer(TickT),
@@ -1201,12 +1206,12 @@ get_proto_mod(_Family, _Protocol, []) ->
 
 %% -------- Initialisation functions ------------------------
 
-init_node(Name, LongOrShortNames) ->
-    {NameWithoutHost,_Host} = lists:splitwith(fun($@)->false;(_)->true end,
-				  atom_to_list(Name)),
+init_node(Name, LongOrShortNames, CleanHalt) ->
+    {NameWithoutHost0,_Host} = split_node(Name),
     case create_name(Name, LongOrShortNames, 1) of
 	{ok,Node} ->
-	    case start_protos(list_to_atom(NameWithoutHost),Node) of
+	    NameWithoutHost = list_to_atom(NameWithoutHost0),
+	    case start_protos(NameWithoutHost, Node, CleanHalt) of
 		{ok, Ls} ->
 		    {ok, Node, Ls};
 		Error ->
@@ -1240,8 +1245,7 @@ create_name(Name, LongOrShortNames, Try) ->
     end.
 
 create_hostpart(Name, LongOrShortNames) ->
-    {Head,Host} = lists:splitwith(fun($@)->false;(_)->true end,
-				  atom_to_list(Name)),
+    {Head,Host} = split_node(Name),
     Host1 = case {Host,LongOrShortNames} of
 		{[$@,_|_],longnames} ->
 		    {ok,Host};
@@ -1268,6 +1272,9 @@ create_hostpart(Name, LongOrShortNames) ->
 	    end,
     {Head,Host1}.
 
+split_node(Name) ->
+    lists:splitwith(fun(C) -> C =/= $@ end, atom_to_list(Name)).
+
 %%
 %%
 %%
@@ -1307,21 +1314,26 @@ epmd_module() ->
 %% Start all protocols
 %%
 
-start_protos(Name,Node) ->
+start_protos(Name, Node, CleanHalt) ->
     case init:get_argument(proto_dist) of
 	{ok, [Protos]} ->
-	    start_protos(Name,Protos, Node);
+	    start_protos(Name, Protos, Node, CleanHalt);
 	_ ->
-	    start_protos(Name,["inet_tcp"], Node)
+	    start_protos(Name, ["inet_tcp"], Node, CleanHalt)
     end.
 
-start_protos(Name,Ps, Node) ->
-    case start_protos(Name, Ps, Node, []) of
-	[] -> {error, badarg};
-	Ls -> {ok, Ls}
+start_protos(Name, Ps, Node, CleanHalt) ->
+    case start_protos(Name, Ps, Node, [], CleanHalt) of
+	[] ->
+	    case CleanHalt of
+		true -> halt(1);
+		false -> {error, badarg}
+	    end;
+	Ls ->
+	    {ok, Ls}
     end.
 
-start_protos(Name, [Proto | Ps], Node, Ls) ->
+start_protos(Name, [Proto | Ps], Node, Ls, CleanHalt) ->
     Mod = list_to_atom(Proto ++ "_dist"),
     case catch Mod:listen(Name) of
 	{ok, {Socket, Address, Creation}} ->
@@ -1334,33 +1346,48 @@ start_protos(Name, [Proto | Ps], Node, Ls) ->
 		      address = Address,
 		      accept = AcceptPid,
 		      module = Mod },
-		    start_protos(Name,Ps, Node, [L|Ls]);
+		    start_protos(Name,Ps, Node, [L|Ls], CleanHalt);
 		_ ->
 		    Mod:close(Socket),
-		    error_logger:info_msg("Invalid node name: ~p~n", [Node]),
-		    start_protos(Name, Ps, Node, Ls)
+		    S = "invalid node name: " ++ atom_to_list(Node),
+		    proto_error(CleanHalt, Proto, S),
+		    start_protos(Name, Ps, Node, Ls, CleanHalt)
 	    end;
 	{'EXIT', {undef,_}} ->
-	    error_logger:info_msg("Protocol: ~tp: not supported~n", [Proto]),
-	    start_protos(Name,Ps, Node, Ls);
+	    proto_error(CleanHalt, Proto, "not supported"),
+	    start_protos(Name, Ps, Node, Ls, CleanHalt);
 	{'EXIT', Reason} ->
-	    error_logger:info_msg("Protocol: ~tp: register error: ~tp~n",
-				  [Proto, Reason]),
-	    start_protos(Name,Ps, Node, Ls);
+	    register_error(CleanHalt, Proto, Reason),
+	    start_protos(Name, Ps, Node, Ls, CleanHalt);
 	{error, duplicate_name} ->
-	    error_logger:info_msg("Protocol: ~tp: the name " ++
-				  atom_to_list(Node) ++
-				  " seems to be in use by another Erlang node",
-				  [Proto]),
-	    start_protos(Name,Ps, Node, Ls);
+	    S = "the name " ++ atom_to_list(Node) ++
+		" seems to be in use by another Erlang node",
+	    proto_error(CleanHalt, Proto, S),
+	    start_protos(Name, Ps, Node, Ls, CleanHalt);
 	{error, Reason} ->
-	    error_logger:info_msg("Protocol: ~tp: register/listen error: ~tp~n",
-				  [Proto, Reason]),
-	    start_protos(Name,Ps, Node, Ls)
+	    register_error(CleanHalt, Proto, Reason),
+	    start_protos(Name, Ps, Node, Ls, CleanHalt)
     end;
-start_protos(_,[], _Node, Ls) ->
+start_protos(_, [], _Node, Ls, _CleanHalt) ->
     Ls.
 
+register_error(false, Proto, Reason) ->
+    S = io_lib:format("register/listen error: ~p", [Reason]),
+    proto_error(false, Proto, lists:flatten(S));
+register_error(true, Proto, Reason) ->
+    S = "Protocol '" ++ Proto ++ "': register/listen error: ",
+    erlang:display_string(S),
+    erlang:display(Reason).
+
+proto_error(CleanHalt, Proto, String) ->
+    S = "Protocol '" ++ Proto ++ "': " ++ String ++ "\n",
+    case CleanHalt of
+	false ->
+	    error_logger:info_msg(S);
+	true ->
+	    erlang:display_string(S)
+    end.
+
 set_node(Node, Creation) when node() =:= nonode@nohost ->
     case catch erlang:setnode(Node, Creation) of
 	true ->