Merge branch 'egil/20/erts/signal-service/OTP-14186'

* egil/20/erts/signal-service/OTP-14186:
  kernel: Document signal server
  erts: Use os module instead of erts_internal for set_signal/2
  erts: Do not handle SIGILL
  erts: Fix thread suspend in crashdump
  erts: Do not enable SIGINT
  erts: Use generic signal handler
  erts: Add OS signal tests
  erts: Handle SIGUSR1 via signal service instead
  erts: Handle SIGTERM via signal service instead
  kernel: Add gen_event signal server and default handler
  erts: Add SIGHUP signal handler
  erts: Remove whitespace errors

Conflicts:
	erts/emulator/beam/bif.tab

7 files changed, 165 insertions, 8 deletions

diff --git a/lib/kernel/doc/src/kernel_app.xml b/lib/kernel/doc/src/kernel_app.xml
index df681a505f..c581fa9d1e 100644
--- a/lib/kernel/doc/src/kernel_app.xml
+++ b/lib/kernel/doc/src/kernel_app.xml
@@ -11,7 +11,7 @@
       Licensed under the Apache License, Version 2.0 (the "License");
       you may not use this file except in compliance with the License.
       You may obtain a copy of the License at
- 
+
           http://www.apache.org/licenses/LICENSE-2.0
 
       Unless required by applicable law or agreed to in writing, software
@@ -19,7 +19,7 @@
       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
       See the License for the specific language governing permissions and
       limitations under the License.
-    
+
     </legalnotice>
 
     <title>kernel</title>
@@ -58,6 +58,60 @@
   </section>
 
   <section>
+      <title>OS Signal Event Handler</title>
+      <p>Asynchronous OS signals may be subscribed to via the Kernel applications event manager
+          (see <seealso marker="doc/design_principles:des_princ">OTP Design Principles</seealso> and
+          <seealso marker="stdlib:gen_event"><c>gen_event(3)</c></seealso>) registered as <c>erl_signal_server</c>.
+          A default signal handler is installed which handles the following signals:</p>
+          <taglist>
+              <tag><c>sigusr1</c></tag>
+              <item><p>The default handler will halt Erlang and produce a crashdump
+                      with slogan "Received SIGUSR1".
+                      This is equivalent to calling <c>erlang:halt("Received SIGUSR1")</c>.
+              </p></item>
+
+              <tag><c>sigquit</c></tag>
+              <item><p>The default handler will halt Erlang immediately.
+                      This is equivalent to calling <c>erlang:halt()</c>.
+              </p></item>
+
+              <tag><c>sigterm</c></tag>
+              <item><p>The default handler will terminate Erlang normally.
+                      This is equivalent to calling <c>init:stop()</c>.
+              </p></item>
+          </taglist>
+
+          <section>
+              <title>Events</title>
+              <p>Any event handler added to <c>erl_signal_server</c> must handle the following events.</p>
+              <taglist>
+                  <tag><c>sighup</c></tag>
+                  <item><p>Hangup detected on controlling terminal or death of controlling process</p></item>
+                  <tag><c>sigquit</c></tag>
+                  <item><p>Quit from keyboard</p></item>
+                  <tag><c>sigabrt</c></tag>
+                  <item><p>Abort signal from abort</p></item>
+                  <tag><c>sigalrm</c></tag>
+                  <item><p>Timer signal from alarm</p></item>
+                  <tag><c>sigterm</c></tag>
+                  <item><p>Termination signal</p></item>
+                  <tag><c>sigusr1</c></tag>
+                  <item><p>User-defined signal 1</p></item>
+                  <tag><c>sigusr2</c></tag>
+                  <item><p>User-defined signal 2</p></item>
+                  <tag><c>sigchld</c></tag>
+                  <item><p>Child process stopped or terminated</p></item>
+                  <tag><c>sigstop</c></tag>
+                  <item><p>Stop process</p></item>
+                  <tag><c>sigtstp</c></tag>
+                  <item><p>Stop typed at terminal</p></item>
+              </taglist>
+
+              <p>Setting OS signals are described in <seealso marker="os#set_signal/2"><c>os:set_signal/2</c></seealso>.</p>
+          </section>
+  </section>
+
+  <section>
     <title>Configuration</title>
     <p>The following configuration parameters are defined for the Kernel
       application. For more information about configuration parameters,
@@ -405,4 +459,3 @@ MaxT = TickTime + TickTime / 4</code>
       <seealso marker="stdlib:timer"><c>timer(3)</c></seealso></p>
   </section>
 </appref>
-
diff --git a/lib/kernel/doc/src/os.xml b/lib/kernel/doc/src/os.xml
index 739ac35d2a..6ba69d12a3 100644
--- a/lib/kernel/doc/src/os.xml
+++ b/lib/kernel/doc/src/os.xml
@@ -11,7 +11,7 @@
       Licensed under the Apache License, Version 2.0 (the "License");
       you may not use this file except in compliance with the License.
       You may obtain a copy of the License at
- 
+
           http://www.apache.org/licenses/LICENSE-2.0
 
       Unless required by applicable law or agreed to in writing, software
@@ -19,7 +19,7 @@
       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
       See the License for the specific language governing permissions and
       limitations under the License.
-    
+
     </legalnotice>
 
     <title>os</title>
@@ -156,6 +156,32 @@ DirOut = os:cmd("dir"), % on Win32 platform</code>
     </func>
 
     <func>
+      <name name="set_signal" arity="2"/>
+      <fsummary>Enables or disables handling of OS signals.</fsummary>
+      <desc>
+          <p>Enables or disables OS signals.</p>
+          <p>Each signal my be set to one of the following options:</p>
+          <taglist>
+              <tag><c>ignore</c></tag>
+              <item>
+                  This signal will be ignored.
+              </item>
+
+              <tag><c>default</c></tag>
+              <item>
+                  This signal will use the default signal handler for the operating system.
+              </item>
+
+              <tag><c>handle</c></tag>
+              <item>
+                  This signal will notify <c>erl_signal_server</c> when it is received by
+                  the Erlang runtime system.
+              </item>
+          </taglist>
+      </desc>
+    </func>
+
+    <func>
       <name name="system_time" arity="0"/>
       <fsummary>Current OS system time.</fsummary>
       <desc>
@@ -296,4 +322,3 @@ calendar:now_to_universal_time(TS),
     </func>
   </funcs>
 </erlref>
-
diff --git a/lib/kernel/src/Makefile b/lib/kernel/src/Makefile
index 2b72f78dcf..2a89faaf13 100644
--- a/lib/kernel/src/Makefile
+++ b/lib/kernel/src/Makefile
@@ -71,6 +71,7 @@ MODULES = \
 	erl_distribution \
 	erl_epmd \
 	erl_reply \
+	erl_signal_handler \
 	erts_debug \
 	error_handler \
 	error_logger \
diff --git a/lib/kernel/src/erl_signal_handler.erl b/lib/kernel/src/erl_signal_handler.erl
new file mode 100644
index 0000000000..8f924d2adc
--- /dev/null
+++ b/lib/kernel/src/erl_signal_handler.erl
@@ -0,0 +1,57 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(erl_signal_handler).
+-behaviour(gen_event).
+-export([init/1, format_status/2,
+         handle_event/2, handle_call/2, handle_info/2,
+         terminate/2, code_change/3]).
+
+-record(state,{}).
+
+init(_Args) ->
+    {ok, #state{}}.
+
+handle_event(sigusr1, S) ->
+    erlang:halt("Received SIGUSR1"),
+    {ok, S};
+handle_event(sigquit, S) ->
+    erlang:halt(),
+    {ok, S};
+handle_event(sigterm, S) ->
+    error_logger:info_msg("SIGTERM received - shutting down~n"),
+    ok = init:stop(),
+    {ok, S};
+handle_event(_SignalMsg, S) ->
+    {ok, S}.
+
+handle_info(_Info, S) ->
+    {ok, S}.
+
+handle_call(_Request, S) ->
+    {ok, ok, S}.
+
+format_status(_Opt, [_Pdict,_S]) ->
+    ok.
+
+code_change(_OldVsn, S, _Extra) ->
+    {ok, S}.
+
+terminate(_Args, _S) ->
+    ok.
diff --git a/lib/kernel/src/kernel.app.src b/lib/kernel/src/kernel.app.src
index 4d08a55c7c..25e4ddd95c 100644
--- a/lib/kernel/src/kernel.app.src
+++ b/lib/kernel/src/kernel.app.src
@@ -34,6 +34,7 @@
 	     erl_boot_server,
 	     erl_distribution,
 	     erl_reply,
+             erl_signal_handler,
 	     error_handler,
 	     error_logger,
 	     file,
diff --git a/lib/kernel/src/kernel.erl b/lib/kernel/src/kernel.erl
index 3d0ef81318..59eca242b1 100644
--- a/lib/kernel/src/kernel.erl
+++ b/lib/kernel/src/kernel.erl
@@ -32,6 +32,14 @@
 start(_, []) ->
     case supervisor:start_link({local, kernel_sup}, kernel, []) of
 	{ok, Pid} ->
+            %% add signal handler
+            case whereis(erl_signal_server) of
+                %% in case of minimal mode
+                undefined -> ok;
+                _ ->
+                    ok = gen_event:add_handler(erl_signal_server, erl_signal_handler, [])
+            end,
+            %% add error handler
 	    Type = get_error_logger_type(),
             case error_logger:swap_handler(Type) of
                 ok -> {ok, Pid, []};
@@ -131,6 +139,9 @@ init([]) ->
 		      permanent, 2000, worker, [inet_db]},
 	    NetSup = {net_sup, {erl_distribution, start_link, []}, 
 		      permanent, infinity, supervisor,[erl_distribution]},
+            SigSrv = #{id => erl_signal_server,
+                       start => {gen_event, start_link, [{local, erl_signal_server}]},
+                       type => worker, restart => permanent, shutdown => 2000, modules => dynamic},
 	    DistAC = start_dist_ac(),
 
 	    Timer = start_timer(),
@@ -141,7 +152,7 @@ init([]) ->
 			      permanent, infinity, supervisor, [?MODULE]},
 	    {ok, {SupFlags,
 		  [Code, Rpc, Global, InetDb | DistAC] ++
-		  [NetSup, Glo_grp, File,
+		  [NetSup, Glo_grp, File, SigSrv,
 		   StdError, User, Config, SafeSupervisor] ++ Timer}}
     end;
 init(safe) ->
diff --git a/lib/kernel/src/os.erl b/lib/kernel/src/os.erl
index f8519d3a5e..c3ffcb3f70 100644
--- a/lib/kernel/src/os.erl
+++ b/lib/kernel/src/os.erl
@@ -29,7 +29,7 @@
 
 -export([getenv/0, getenv/1, getenv/2, getpid/0,
          perf_counter/0, perf_counter/1,
-         putenv/2, system_time/0, system_time/1,
+         putenv/2, set_signal/2, system_time/0, system_time/1,
 	 timestamp/0, unsetenv/1]).
 
 -spec getenv() -> [string()].
@@ -104,6 +104,15 @@ timestamp() ->
 unsetenv(_) ->
     erlang:nif_error(undef).
 
+-spec set_signal(Signal, Option) -> 'ok' when
+      Signal :: 'sighup'  | 'sigquit' | 'sigabrt' | 'sigalrm' |
+                'sigterm' | 'sigusr1' | 'sigusr2' | 'sigchld' |
+                'sigstop' | 'sigtstp',
+      Option :: 'default' | 'handle' | 'ignore'.
+
+set_signal(_Signal, _Option) ->
+    erlang:nif_error(undef).
+
 %%% End of BIFs
 
 -spec type() -> {Osfamily, Osname} when