From 990ddca5415d196bf7543a57a86aa47da13706c6 Mon Sep 17 00:00:00 2001
From: Siri Hansen <siri@erlang.org>
Date: Wed, 13 Sep 2017 16:32:58 +0200
Subject: cdv: Warn about unsafe crashdump

Warn the user if the node executing the crashdump viewer potentially
could overwrite the crashdump under inspection.
---
 lib/observer/src/cdv_wx.erl           | 35 +++++++++++++++++++++++++++++++++++
 lib/observer/src/crashdump_viewer.erl |  3 ++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/lib/observer/src/cdv_wx.erl b/lib/observer/src/cdv_wx.erl
index ffd7694ab3..c3f36cd689 100644
--- a/lib/observer/src/cdv_wx.erl
+++ b/lib/observer/src/cdv_wx.erl
@@ -412,6 +412,14 @@ load_dump(Frame,undefined) ->
 	    error
     end;
 load_dump(Frame,FileName) ->
+    case maybe_warn_filename(FileName) of
+        continue ->
+            do_load_dump(Frame,FileName);
+        stop ->
+            error
+    end.
+
+do_load_dump(Frame,FileName) ->
     ok = observer_lib:display_progress_dialog(wx:null(),
                                               "Crashdump Viewer",
 					      "Loading crashdump"),
@@ -432,6 +440,33 @@ load_dump(Frame,FileName) ->
 	    error
     end.
 
+maybe_warn_filename(FileName) ->
+    case os:getenv("ERL_CRASH_DUMP_SECONDS")=="0" orelse
+        os:getenv("ERL_CRASH_DUMP_BYTES")=="0" of
+        true ->
+            continue;
+        false ->
+            DumpName = case os:getenv("ERL_CRASH_DUMP") of
+                           false -> filename:absname("erl_crash.dump");
+                           Name -> filename:absname(Name)
+                       end,
+            case filename:absname(FileName) of
+                DumpName ->
+                    Warning =
+                        "WARNING: the current crashdump might be overwritten "
+                        "if the crashdump_viewer node crashes.\n\n"
+                        "Renaming the file before inspecting it will "
+                        "remove the problem.\n\n"
+                        "Do you want to continue?",
+                    case observer_lib:display_yes_no_dialog(Warning) of
+                        ?wxID_YES -> continue;
+                        ?wxID_NO -> stop
+                    end;
+                _ ->
+                    continue
+            end
+    end.
+
 %%%-----------------------------------------------------------------
 %%% Find help document (HTML files)
 get_help_doc(HelpId) ->
diff --git a/lib/observer/src/crashdump_viewer.erl b/lib/observer/src/crashdump_viewer.erl
index b01c3a1bac..95e12887cd 100644
--- a/lib/observer/src/crashdump_viewer.erl
+++ b/lib/observer/src/crashdump_viewer.erl
@@ -205,7 +205,8 @@ do_script_start(StartFun) ->
 			    io:format("\ncdv crash: ~tp\n",[Reason])
 		    end;
 		_ ->
-		    io:format("\ncdv crash: ~p\n",[unknown_reason])
+		    %io:format("\ncdv crash: ~p\n",[unknown_reason])
+                    ok
 	    end;
 	Error ->
 	    io:format("\ncdv start failed: ~tp\n",[Error])
-- 
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