stdlib: Limit the size of proc_lib's crash reports

The size of the message queue and the dictionary is limited in
crash reports.

To avoid creating the potentially huge list of messages of the message
queue, messages are received (if the Kernel variable
error_logger_format_depth is set).

The tag 'message_queue_len' has been added to the crash report.

1 files changed, 86 insertions, 25 deletions

diff --git a/lib/stdlib/src/proc_lib.erl b/lib/stdlib/src/proc_lib.erl
index 2219467a8d..b2856be805 100644
--- a/lib/stdlib/src/proc_lib.erl
+++ b/lib/stdlib/src/proc_lib.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2016. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2017. 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.
@@ -519,7 +519,8 @@ my_info_1(Class, Reason, Stacktrace) ->
      get_process_info(self(), registered_name),         
      {error_info, {Class,Reason,Stacktrace}},
      get_ancestors(self()),        
-     get_process_info(self(), messages),
+     get_process_info(self(), message_queue_len),
+     get_messages(self()),
      get_process_info(self(), links),
      get_cleaned_dictionary(self()),
      get_process_info(self(), trap_exit),
@@ -539,12 +540,56 @@ get_ancestors(Pid) ->
 	    {ancestors,[]}
     end.
 
+%% The messages and the dictionary are possibly limited too much if
+%% some error handles output the messages or the dictionary using ~P
+%% or ~W with depth greater than the depth used here (the depth of
+%% control characters P and W takes precedence over the depth set by
+%% application variable error_logger_format_depth). However, it is
+%% assumed that all report handlers call proc_lib:format().
+get_messages(Pid) ->
+    Messages = get_process_messages(Pid),
+    {messages, error_logger:limit_term(Messages)}.
+
+get_process_messages(Pid) ->
+    case get_depth() of
+        unlimited ->
+            {messages, Messages} = get_process_info(Pid, messages),
+            Messages;
+        Depth ->
+            %% If there are more messages than Depth, garbage
+            %% collection can sometimes be avoided by collecting just
+            %% enough messages for the output. It is assumed the
+            %% process is about to die anyway.
+            receive_messages(Depth)
+    end.
+
+get_depth() ->
+    case application:get_env(kernel, error_logger_format_depth) of
+	{ok, Depth} when is_integer(Depth) ->
+	    max(10, Depth);
+	undefined ->
+	    unlimited
+    end.
+
+receive_messages(0) -> [];
+receive_messages(N) ->
+    receive
+        M ->
+            [M|receive_messages(N - 1)]
+    after 0 ->
+            []
+    end.
+
 get_cleaned_dictionary(Pid) ->
     case get_process_info(Pid,dictionary) of
-	{dictionary,Dict} -> {dictionary,clean_dict(Dict)};
+	{dictionary,Dict} -> {dictionary,cleaned_dict(Dict)};
 	_                 -> {dictionary,[]}
     end.
 
+cleaned_dict(Dict) ->
+    CleanDict = clean_dict(Dict),
+    error_logger:limit_term(CleanDict).
+
 clean_dict([{'$ancestors',_}|Dict]) ->
     clean_dict(Dict);
 clean_dict([{'$initial_call',_}|Dict]) ->
@@ -582,15 +627,18 @@ make_neighbour_reports1([P|Ps]) ->
 make_neighbour_reports1([]) ->
   [].
   
+%% Do not include messages or process dictionary, even if
+%% error_logger_format_depth is unlimited.
 make_neighbour_report(Pid) ->
   [{pid, Pid},
    get_process_info(Pid, registered_name),          
    get_initial_call(Pid),
    get_process_info(Pid, current_function),
    get_ancestors(Pid),
-   get_process_info(Pid, messages),
+   get_process_info(Pid, message_queue_len),
+   %% get_messages(Pid),
    get_process_info(Pid, links),
-   get_cleaned_dictionary(Pid),
+   %% get_cleaned_dictionary(Pid),
    get_process_info(Pid, trap_exit),
    get_process_info(Pid, status),
    get_process_info(Pid, heap_size),
@@ -722,24 +770,37 @@ format(CrashReport, Encoding) ->
 
 format([OwnReport,LinkReport], Encoding, Depth) ->
     Extra = {Encoding,Depth},
-    OwnFormat = format_report(OwnReport, Extra),
-    LinkFormat = format_report(LinkReport, Extra),
+    MyIndent = "    ",
+    OwnFormat = format_report(OwnReport, MyIndent, Extra),
+    LinkFormat = format_link_report(LinkReport, MyIndent, Extra),
     Str = io_lib:format("  crasher:~n~ts  neighbours:~n~ts",
                         [OwnFormat, LinkFormat]),
     lists:flatten(Str).
 
-format_report(Rep, Extra) when is_list(Rep) ->
-    format_rep(Rep, Extra);
-format_report(Rep, {Enc,_}) ->
-    io_lib:format("~"++modifier(Enc)++"p~n", [Rep]).
-
-format_rep([{initial_call,InitialCall}|Rep], {_Enc,Depth}=Extra) ->
-    [format_mfa(InitialCall, Depth)|format_rep(Rep, Extra)];
-format_rep([{error_info,{Class,Reason,StackTrace}}|Rep], Extra) ->
-    [format_exception(Class, Reason, StackTrace, Extra)|format_rep(Rep, Extra)];
-format_rep([{Tag,Data}|Rep], Extra) ->
-    [format_tag(Tag, Data, Extra)|format_rep(Rep, Extra)];
-format_rep(_, _Extra) ->
+format_link_report([Link|Reps], Indent, Extra) ->
+    Rep = case Link of
+              {neighbour,Rep0} -> Rep0;
+              _ -> Link
+          end,
+    LinkIndent = ["  ",Indent],
+    [Indent,"neighbour:\n",format_report(Rep, LinkIndent, Extra)|
+     format_link_report(Reps, Indent, Extra)];
+format_link_report([], _, _) ->
+    [].
+
+format_report(Rep, Indent, Extra) when is_list(Rep) ->
+    format_rep(Rep, Indent, Extra);
+format_report(Rep, Indent, {Enc,Depth}) ->
+    io_lib:format("~s~"++modifier(Enc)++"P~n", [Indent, Rep, Depth]).
+
+format_rep([{initial_call,InitialCall}|Rep], Indent, Extra) ->
+    [format_mfa(Indent, InitialCall, Extra)|format_rep(Rep, Indent, Extra)];
+format_rep([{error_info,{Class,Reason,StackTrace}}|Rep], Indent, Extra) ->
+    [format_exception(Class, Reason, StackTrace, Extra)|
+     format_rep(Rep, Indent, Extra)];
+format_rep([{Tag,Data}|Rep], Indent, Extra) ->
+    [format_tag(Indent, Tag, Data, Extra)|format_rep(Rep, Indent, Extra)];
+format_rep(_, _, _Extra) ->
     [].
 
 format_exception(Class, Reason, StackTrace, {Enc,_}=Extra) ->
@@ -750,14 +811,14 @@ format_exception(Class, Reason, StackTrace, {Enc,_}=Extra) ->
     [EI, lib:format_exception(1+length(EI), Class, Reason, 
                               StackTrace, StackFun, PF, Enc), "\n"].
 
-format_mfa({M,F,Args}=StartF, Depth) ->
+format_mfa(Indent, {M,F,Args}=StartF, Extra) ->
     try
 	A = length(Args),
-	["    initial call: ",atom_to_list(M),$:,atom_to_list(F),$/,
+	[Indent,"initial call: ",atom_to_list(M),$:,atom_to_list(F),$/,
 	 integer_to_list(A),"\n"]
     catch
 	error:_ ->
-	    format_tag(initial_call, StartF, Depth)
+	    format_tag(Indent, initial_call, StartF, Extra)
     end.
 
 pp_fun({Enc,Depth}) ->
@@ -770,12 +831,12 @@ pp_fun({Enc,Depth}) ->
             io_lib:format("~." ++ integer_to_list(I) ++ P, [Term|Tl])
     end.
 
-format_tag(Tag, Data, {_Enc,Depth}) ->
+format_tag(Indent, Tag, Data, {_Enc,Depth}) ->
     case Depth of
 	unlimited ->
-	    io_lib:format("    ~p: ~80.18p~n", [Tag, Data]);
+	    io_lib:format("~s~p: ~80.18p~n", [Indent, Tag, Data]);
 	_ ->
-	    io_lib:format("    ~p: ~80.18P~n", [Tag, Data, Depth])
+            io_lib:format("~s~p: ~80.18P~n", [Indent, Tag, Data, Depth])
     end.
 
 modifier(latin1) -> "";