Merge branch 'siri/sasl/xxgrade_app-with-restart/OTP-9735'

* siri/sasl/xxgrade_app-with-restart/OTP-9735:
  Fix release_handler:upgrade_app and downgrade_app when upgrading emulator

14 files changed, 315 insertions, 11 deletions

diff --git a/lib/sasl/doc/src/release_handler.xml b/lib/sasl/doc/src/release_handler.xml
index 7f32100d4b..bd4a513750 100644
--- a/lib/sasl/doc/src/release_handler.xml
+++ b/lib/sasl/doc/src/release_handler.xml
@@ -492,7 +492,7 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]).
   </section>
   <funcs>
     <func>
-      <name>upgrade_app(App, Dir) -> {ok, Unpurged} | restart_new_emulator | {error, Reason}</name>
+      <name>upgrade_app(App, Dir) -> {ok, Unpurged} | restart_emulator | {error, Reason}</name>
       <fsummary>Upgrade to a new application version</fsummary>
       <type>
         <v>App = atom()</v>
@@ -521,14 +521,21 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]).
           does.</p>
         <p>Returns <c>{ok, Unpurged}</c> if evaluating the script is
           successful, where <c>Unpurged</c> is a list of unpurged
-          modules, or <c>restart_new_emulator</c> if this instruction is
+          modules, or <c>restart_emulator</c> if this instruction is
           encountered in the script, or <c>{error, Reason}</c> if
           an error occurred when finding or evaluating the script.</p>
+	<p>If the <c>restart_new_emulator</c> instruction is found in
+	  the script, <c>upgrade_app/2</c> will return
+	  <c>{error,restart_new_emulator}</c>. The reason for this is
+	  that this instruction requires that a new version of the
+	  emulator is started before the rest of the upgrade
+	  instructions can be executed, and this can only be done by
+          <c>install_release/1,2</c>.</p>
       </desc>
     </func>
     <func>
       <name>downgrade_app(App, Dir) -></name>
-      <name>downgrade_app(App, OldVsn, Dir) -> {ok, Unpurged} | restart_new_emulator | {error, Reason}</name>
+      <name>downgrade_app(App, OldVsn, Dir) -> {ok, Unpurged} | restart_emulator | {error, Reason}</name>
       <fsummary>Downgrade to a previous application version</fsummary>
       <type>
         <v>App = atom()</v>
@@ -562,7 +569,7 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]).
           does.</p>
         <p>Returns <c>{ok, Unpurged}</c> if evaluating the script is
           successful, where <c>Unpurged</c> is a list of unpurged
-          modules, or <c>restart_new_emulator</c> if this instruction is
+          modules, or <c>restart_emulator</c> if this instruction is
           encountered in the script, or <c>{error, Reason}</c> if
           an error occurred when finding or evaluating the script.</p>
       </desc>
@@ -638,7 +645,7 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]).
       </desc>
     </func>
     <func>
-      <name>eval_appup_script(App, ToVsn, ToDir, Script) -> {ok, Unpurged} | restart_new_emulator | {error, Reason}</name>
+      <name>eval_appup_script(App, ToVsn, ToDir, Script) -> {ok, Unpurged} | restart_emulator | {error, Reason}</name>
       <fsummary>Evaluate an application upgrade or downgrade script</fsummary>
       <type>
         <v>App = atom()</v>
@@ -651,8 +658,8 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]).
       <desc>
         <p>Evaluates an application upgrade or downgrade script
           <c>Script</c>, the result from calling
-          <seealso marker="#upgrade_app/2">upgrade_app/2</seealso> or
-          <seealso marker="#downgrade_app/3">downgrade_app/2,3</seealso>,
+          <seealso marker="#upgrade_app/2">upgrade_script/2</seealso> or
+          <seealso marker="#downgrade_app/3">downgrade_script/3</seealso>,
           exactly in the same way as
           <seealso marker="#install_release/1">install_release/1,2</seealso>
           does.</p>
@@ -663,9 +670,16 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]).
           <c>.appup</c> files should be located under <c>Dir/ebin</c>.</p>
         <p>Returns <c>{ok, Unpurged}</c> if evaluating the script is
           successful, where <c>Unpurged</c> is a list of unpurged
-          modules, or <c>restart_new_emulator</c> if this instruction is
+          modules, or <c>restart_emulator</c> if this instruction is
           encountered in the script, or <c>{error, Reason}</c> if
           an error occurred when evaluating the script.</p>
+	<p>If the <c>restart_new_emulator</c> instruction is found in
+	  the script, <c>eval_appup_script/4</c> will return
+	  <c>{error,restart_new_emulator}</c>. The reason for this is
+	  that this instruction requires that a new version of the
+	  emulator is started before the rest of the upgrade
+	  instructions can be executed, and this can only be done by
+          <c>install_release/1,2</c>.</p>
       </desc>
     </func>
   </funcs>
diff --git a/lib/sasl/src/release_handler_1.erl b/lib/sasl/src/release_handler_1.erl
index b4b288646f..37275eff45 100644
--- a/lib/sasl/src/release_handler_1.erl
+++ b/lib/sasl/src/release_handler_1.erl
@@ -459,7 +459,9 @@ eval({apply, {M, F, A}}, EvalState) ->
     apply(M, F, A),
     EvalState;
 eval(restart_emulator, _EvalState) ->
-    throw(restart_emulator).
+    throw(restart_emulator);
+eval(restart_new_emulator, _EvalState) ->
+    throw(restart_new_emulator).
 
 get_opt(Tag, EvalState, Default) ->
     case lists:keysearch(Tag, 1, EvalState#eval_state.opts) of
diff --git a/lib/sasl/test/release_handler_SUITE.erl b/lib/sasl/test/release_handler_SUITE.erl
index 11f8bbe4fe..454fe26323 100644
--- a/lib/sasl/test/release_handler_SUITE.erl
+++ b/lib/sasl/test/release_handler_SUITE.erl
@@ -60,7 +60,8 @@ cases() ->
     [otp_2740, otp_2760, otp_5761, otp_9402, otp_9417,
      otp_9395_check_old_code, otp_9395_check_and_purge,
      otp_9395_update_many_mods, otp_9395_rm_many_mods,
-     instructions, eval_appup, supervisor_which_children_timeout,
+     instructions, eval_appup, eval_appup_with_restart,
+     supervisor_which_children_timeout,
      release_handler_which_releases, install_release_syntax_check].
 
 groups() ->
@@ -1226,6 +1227,12 @@ eval_appup(Conf) when is_list(Conf) ->
     App11Dir = code:lib_dir(app1),
     ok = gen_server:call(harry, error),
 
+    %% Read appup script
+    {ok,"2.0",UpScript} = release_handler:upgrade_script(app1,App12Dir),
+    [{load_object_code,_},
+     point_of_no_return,
+     {load,_}] = UpScript,
+
     %% Upgrade to app1-2.0
     {ok, []} = release_handler:upgrade_app(app1, App12Dir),
     App12Dir = code:lib_dir(app1),
@@ -1236,6 +1243,12 @@ eval_appup(Conf) when is_list(Conf) ->
     %% (see myrel/lib2/app1-2.0/ebin/app1.app)
     [{var,val2}] = ets:lookup(otp_6162, var),
 
+    %% Read appup script
+    {ok,DnScript} = release_handler:downgrade_script(app1,"1.0",App11Dir),
+    [{load_object_code,_},
+     point_of_no_return,
+     {load,_}] = DnScript,
+
     %% Downgrade to app1-1.0
     {ok, []} = release_handler:downgrade_app(app1,"1.0",App11Dir),
     App11Dir = code:lib_dir(app1),
@@ -1253,6 +1266,85 @@ eval_appup(Conf) when is_list(Conf) ->
     ok.
 
 
+%% Test upgrade and downgrade of applications when appup contains
+%% restart_emulator and restart_new_emulator instructions
+eval_appup_with_restart(Conf) when is_list(Conf) ->
+
+    %% Set some paths
+    RelDir = filename:join(?config(data_dir, Conf), "app1_app2"),
+    App11Dir = filename:join([RelDir, "lib1", "app1-1.0"]),
+    App13Dir = filename:join([RelDir, "lib3", "app1-3.0"]), %restart_emulator
+    App14Dir = filename:join([RelDir, "lib4", "app1-4.0"]), %restart_new_emulator
+    EbinDir1 = filename:join(App11Dir, "ebin"),
+    EbinDir3 = filename:join(App13Dir, "ebin"),
+    EbinDir4 = filename:join(App14Dir, "ebin"),
+
+    %% Start app1-1.0
+    code:add_patha(EbinDir1),
+    ok = application:start(app1),
+    App11Dir = code:lib_dir(app1),
+
+    %% Read appup script
+    {ok,"3.0",UpScript3} = release_handler:upgrade_script(app1,App13Dir),
+    [{load_object_code,_},
+     point_of_no_return,
+     {load,_},
+     restart_emulator] = UpScript3,
+
+    %% Upgrade to app1-3.0 - restart_emulator
+    restart_emulator = release_handler:upgrade_app(app1, App13Dir),
+    App13Dir = code:lib_dir(app1),
+
+    %% Fake full upgrade to 3.0
+    {ok,AppSpec} = file:consult(filename:join([App13Dir,"ebin","app1.app"])),
+    application_controller:change_application_data(AppSpec,[]),
+
+    %% Read appup script
+    {ok,"4.0",UpScript4} = release_handler:upgrade_script(app1,App14Dir),
+    [restart_new_emulator,point_of_no_return] = UpScript4,
+
+    %% Try pgrade to app1-4.0 - restart_new_emulator
+    {error,restart_new_emulator} = release_handler:upgrade_app(app1, App14Dir),
+    App13Dir = code:lib_dir(app1),
+
+    %% Read appup script
+    {ok,DnScript1} = release_handler:downgrade_script(app1,"1.0",App11Dir),
+    [{load_object_code,_},
+     point_of_no_return,
+     {load,_},
+     restart_emulator] = DnScript1,
+
+    %% Still running 3.0 - downgrade to app1-1.0 - restart_emulator
+    restart_emulator = release_handler:downgrade_app(app1,"1.0",App11Dir),
+    App11Dir = code:lib_dir(app1),
+
+    ok = application:stop(app1),
+    ok = application:unload(app1),
+    true = code:del_path(EbinDir1),
+
+    %% Start again as version 4.0
+    code:add_patha(EbinDir4),
+    ok = application:start(app1),
+    App14Dir = code:lib_dir(app1),
+
+    %% Read appup script
+    {ok,DnScript3} = release_handler:downgrade_script(app1,"3.0",App13Dir),
+    [point_of_no_return,restart_emulator] = DnScript3,
+
+    %% Downgrade to app1-3.0 - restart_new_emulator
+    restart_emulator = release_handler:downgrade_app(app1,"3.0",App13Dir),
+    App13Dir = code:lib_dir(app1),
+
+    ok = application:stop(app1),
+    ok = application:unload(app1),
+
+    true = code:del_path(EbinDir3),
+    false = code:del_path(EbinDir1),
+    false = code:del_path(EbinDir4),
+
+    ok.
+
+
 %% Test the example/target_system.erl module
 target_system(Conf) when is_list(Conf) ->
     PrivDir = priv_dir(Conf),
diff --git a/lib/sasl/test/release_handler_SUITE_data/Makefile.src b/lib/sasl/test/release_handler_SUITE_data/Makefile.src
index edb446413d..6f40088161 100644
--- a/lib/sasl/test/release_handler_SUITE_data/Makefile.src
+++ b/lib/sasl/test/release_handler_SUITE_data/Makefile.src
@@ -50,7 +50,13 @@ APP= \
      app1_app2/lib2/app1-2.0/ebin/app1.@EMULATOR@ \
      app1_app2/lib2/app2-1.0/ebin/app2_sup.@EMULATOR@ \
      app1_app2/lib2/app2-1.0/ebin/app2_server.@EMULATOR@ \
-     app1_app2/lib2/app2-1.0/ebin/app2.@EMULATOR@
+     app1_app2/lib2/app2-1.0/ebin/app2.@EMULATOR@ \
+     app1_app2/lib3/app1-3.0/ebin/app1_sup.@EMULATOR@ \
+     app1_app2/lib3/app1-3.0/ebin/app1_server.@EMULATOR@ \
+     app1_app2/lib3/app1-3.0/ebin/app1.@EMULATOR@ \
+     app1_app2/lib4/app1-4.0/ebin/app1_sup.@EMULATOR@ \
+     app1_app2/lib4/app1-4.0/ebin/app1_server.@EMULATOR@ \
+     app1_app2/lib4/app1-4.0/ebin/app1.@EMULATOR@
 
 OTP2740=  \
      otp_2740/vsn_atom.@EMULATOR@ \
@@ -183,6 +189,22 @@ app1_app2/lib2/app2-1.0/ebin/app2.@EMULATOR@: app1_app2/lib2/app2-1.0/src/app2.e
 	erlc $(EFLAGS) -oapp1_app2/lib2/app2-1.0/ebin app1_app2/lib2/app2-1.0/src/app2.erl
 
 
+app1_app2/lib3/app1-3.0/ebin/app1_sup.@EMULATOR@: app1_app2/lib3/app1-3.0/src/app1_sup.erl
+	erlc $(EFLAGS) -oapp1_app2/lib3/app1-3.0/ebin app1_app2/lib3/app1-3.0/src/app1_sup.erl
+app1_app2/lib3/app1-3.0/ebin/app1_server.@EMULATOR@: app1_app2/lib3/app1-3.0/src/app1_server.erl
+	erlc $(EFLAGS) -oapp1_app2/lib3/app1-3.0/ebin app1_app2/lib3/app1-3.0/src/app1_server.erl
+app1_app2/lib3/app1-3.0/ebin/app1.@EMULATOR@: app1_app2/lib3/app1-3.0/src/app1.erl
+	erlc $(EFLAGS) -oapp1_app2/lib3/app1-3.0/ebin app1_app2/lib3/app1-3.0/src/app1.erl
+
+
+app1_app2/lib4/app1-4.0/ebin/app1_sup.@EMULATOR@: app1_app2/lib4/app1-4.0/src/app1_sup.erl
+	erlc $(EFLAGS) -oapp1_app2/lib4/app1-4.0/ebin app1_app2/lib4/app1-4.0/src/app1_sup.erl
+app1_app2/lib4/app1-4.0/ebin/app1_server.@EMULATOR@: app1_app2/lib4/app1-4.0/src/app1_server.erl
+	erlc $(EFLAGS) -oapp1_app2/lib4/app1-4.0/ebin app1_app2/lib4/app1-4.0/src/app1_server.erl
+app1_app2/lib4/app1-4.0/ebin/app1.@EMULATOR@: app1_app2/lib4/app1-4.0/src/app1.erl
+	erlc $(EFLAGS) -oapp1_app2/lib4/app1-4.0/ebin app1_app2/lib4/app1-4.0/src/app1.erl
+
+
 otp_2740/vsn_atom.@EMULATOR@: otp_2740/vsn_atom.erl
 	erlc $(EFLAGS) -ootp_2740 otp_2740/vsn_atom.erl
 otp_2740/vsn_list.@EMULATOR@: otp_2740/vsn_list.erl
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/ebin/app1.app b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/ebin/app1.app
new file mode 100644
index 0000000000..4adc0540c4
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/ebin/app1.app
@@ -0,0 +1,9 @@
+{application, app1,
+ [{description, "very simple example application"},
+  {id, "app1"},
+  {vsn, "3.0"},
+  {modules, [app1, app1_sup, app1_server]},
+  {registered, [harry]},
+  {applications, [kernel, stdlib, sasl]},
+  {env, [{var,val2}]},
+  {mod, {app1, []}}]}.
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/ebin/app1.appup b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/ebin/app1.appup
new file mode 100644
index 0000000000..a5cdfe9fcc
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/ebin/app1.appup
@@ -0,0 +1,4 @@
+{"3.0",
+ [{"1.0", [{load_module, app1_server},restart_emulator]}],
+ [{"1.0", [{load_module, app1_server},restart_emulator]}]
+}.
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/src/app1.erl b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/src/app1.erl
new file mode 100644
index 0000000000..f123c8f470
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/src/app1.erl
@@ -0,0 +1,22 @@
+-module(app1).
+
+-behaviour(application).
+
+%% Application callbacks
+-export([start/2, stop/1]).
+-export([config_change/3]).
+
+start(_Type, _StartArgs) ->
+    case app1_sup:start_link() of
+	{ok, Pid} ->
+	    {ok, Pid};
+	Error ->
+	    Error
+    end.
+
+stop(_State) ->
+    ok.
+
+config_change(Changed, _New, _Removed) ->
+    catch ets:insert(otp_6162, hd(Changed)),
+    ok.
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/src/app1_server.erl b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/src/app1_server.erl
new file mode 100644
index 0000000000..660d095ebf
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/src/app1_server.erl
@@ -0,0 +1,35 @@
+-module(app1_server).
+
+-behaviour(gen_server).
+
+%% API
+-export([start_link/0]).
+
+%% gen_server callbacks
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
+	 terminate/2, code_change/3]).
+
+start_link() ->
+    gen_server:start_link({local, harry}, ?MODULE, [], []).
+
+init([]) ->
+    {ok, []}.
+
+handle_call(error, _From, State) ->
+    Reply = error,
+    {reply, Reply, State};
+handle_call(_Request, _From, State) ->
+    Reply = ok,
+    {reply, Reply, State}.
+
+handle_cast(_Msg, State) ->
+    {noreply, State}.
+
+handle_info(_Info, State) ->
+    {noreply, State}.
+
+terminate(_Reason, _State) ->
+    ok.
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/src/app1_sup.erl b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/src/app1_sup.erl
new file mode 100644
index 0000000000..e6ad9b6967
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib3/app1-3.0/src/app1_sup.erl
@@ -0,0 +1,17 @@
+-module(app1_sup).
+
+-behaviour(supervisor).
+
+%% API
+-export([start_link/0]).
+
+%% Supervisor callbacks
+-export([init/1]).
+
+start_link() ->
+    supervisor:start_link(?MODULE, []).
+
+init([]) ->
+    AChild = {harry,{app1_server,start_link,[]},
+	      permanent,2000,worker,[app1_server]},
+    {ok,{{one_for_all,0,1}, [AChild]}}.
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/ebin/app1.app b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/ebin/app1.app
new file mode 100644
index 0000000000..243bc21f02
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/ebin/app1.app
@@ -0,0 +1,9 @@
+{application, app1,
+ [{description, "very simple example application"},
+  {id, "app1"},
+  {vsn, "4.0"},
+  {modules, [app1, app1_sup, app1_server]},
+  {registered, [harry]},
+  {applications, [kernel, stdlib, sasl]},
+  {env, [{var,val2}]},
+  {mod, {app1, []}}]}.
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/ebin/app1.appup b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/ebin/app1.appup
new file mode 100644
index 0000000000..72535c8b34
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/ebin/app1.appup
@@ -0,0 +1,4 @@
+{"4.0",
+ [{"3.0", [restart_new_emulator]}],
+ [{"3.0", [restart_new_emulator]}]
+}.
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/src/app1.erl b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/src/app1.erl
new file mode 100644
index 0000000000..f123c8f470
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/src/app1.erl
@@ -0,0 +1,22 @@
+-module(app1).
+
+-behaviour(application).
+
+%% Application callbacks
+-export([start/2, stop/1]).
+-export([config_change/3]).
+
+start(_Type, _StartArgs) ->
+    case app1_sup:start_link() of
+	{ok, Pid} ->
+	    {ok, Pid};
+	Error ->
+	    Error
+    end.
+
+stop(_State) ->
+    ok.
+
+config_change(Changed, _New, _Removed) ->
+    catch ets:insert(otp_6162, hd(Changed)),
+    ok.
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/src/app1_server.erl b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/src/app1_server.erl
new file mode 100644
index 0000000000..660d095ebf
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/src/app1_server.erl
@@ -0,0 +1,35 @@
+-module(app1_server).
+
+-behaviour(gen_server).
+
+%% API
+-export([start_link/0]).
+
+%% gen_server callbacks
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
+	 terminate/2, code_change/3]).
+
+start_link() ->
+    gen_server:start_link({local, harry}, ?MODULE, [], []).
+
+init([]) ->
+    {ok, []}.
+
+handle_call(error, _From, State) ->
+    Reply = error,
+    {reply, Reply, State};
+handle_call(_Request, _From, State) ->
+    Reply = ok,
+    {reply, Reply, State}.
+
+handle_cast(_Msg, State) ->
+    {noreply, State}.
+
+handle_info(_Info, State) ->
+    {noreply, State}.
+
+terminate(_Reason, _State) ->
+    ok.
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
diff --git a/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/src/app1_sup.erl b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/src/app1_sup.erl
new file mode 100644
index 0000000000..e6ad9b6967
--- /dev/null
+++ b/lib/sasl/test/release_handler_SUITE_data/app1_app2/lib4/app1-4.0/src/app1_sup.erl
@@ -0,0 +1,17 @@
+-module(app1_sup).
+
+-behaviour(supervisor).
+
+%% API
+-export([start_link/0]).
+
+%% Supervisor callbacks
+-export([init/1]).
+
+start_link() ->
+    supervisor:start_link(?MODULE, []).
+
+init([]) ->
+    AChild = {harry,{app1_server,start_link,[]},
+	      permanent,2000,worker,[app1_server]},
+    {ok,{{one_for_all,0,1}, [AChild]}}.