From 6c298a7bfa332e5b7d153648d741740abc3bcdf8 Mon Sep 17 00:00:00 2001 From: Steve Vinoski Date: Wed, 19 Mar 2014 11:45:11 -0400 Subject: fix sys:get_state/1,2 and sys:replace_state/2,3 when sys suspended Add two new system callbacks Module:system_get_state/1 and Module:system_replace_state/2 to allow sys:get_state/1,2 and sys:replace_state/2,3 to operate correctly even if a process is sys suspended. Modify gen_server, gen_fsm, and gen_event to support the new callbacks. If a callback module does not export these functions, then by default the Misc value (the same as that passed as the final argument to sys:handle_system_msg/6, and returned as part of the return value of sys:get_status/1,2) is treated as the callback module's state. The previous behaviour of intercepting the system message and passing a tuple of size 2 as the last argument to sys:handle_system_msg/6 is no longer supported. Add tests to verify the correctness of sys:get_state/1,2 and sys:replace_state/2,3 when processes are sys suspended. Add two tests for modules that implement special processes, one that exports system_get_state/1 and system_replace_state/2 and one that doesn't. Much of the credit for this patch goes to James Fish, who reported the initial problem and implemented much of the fix. --- lib/stdlib/test/Makefile | 2 + lib/stdlib/test/gen_event_SUITE.erl | 11 ++++ lib/stdlib/test/gen_fsm_SUITE.erl | 20 +++++- lib/stdlib/test/gen_server_SUITE.erl | 15 ++++- lib/stdlib/test/sys_SUITE.erl | 84 ++++++++++++++++++++++++-- lib/stdlib/test/sys_sp1.erl | 114 +++++++++++++++++++++++++++++++++++ lib/stdlib/test/sys_sp2.erl | 107 ++++++++++++++++++++++++++++++++ 7 files changed, 347 insertions(+), 6 deletions(-) create mode 100644 lib/stdlib/test/sys_sp1.erl create mode 100644 lib/stdlib/test/sys_sp2.erl (limited to 'lib/stdlib/test') diff --git a/lib/stdlib/test/Makefile b/lib/stdlib/test/Makefile index af82f22b21..39f6ce423a 100644 --- a/lib/stdlib/test/Makefile +++ b/lib/stdlib/test/Makefile @@ -73,6 +73,8 @@ MODULES= \ supervisor_SUITE \ supervisor_bridge_SUITE \ sys_SUITE \ + sys_sp1 \ + sys_sp2 \ tar_SUITE \ timer_SUITE \ timer_simple_SUITE \ diff --git a/lib/stdlib/test/gen_event_SUITE.erl b/lib/stdlib/test/gen_event_SUITE.erl index 5819ef3890..60a1ba8c60 100644 --- a/lib/stdlib/test/gen_event_SUITE.erl +++ b/lib/stdlib/test/gen_event_SUITE.erl @@ -974,6 +974,10 @@ get_state(Config) when is_list(Config) -> [{dummy1_h,false,State1},{dummy1_h,id,State2}] = lists:sort(Result1), Result2 = sys:get_state(Pid, 5000), [{dummy1_h,false,State1},{dummy1_h,id,State2}] = lists:sort(Result2), + ok = sys:suspend(Pid), + Result3 = sys:get_state(Pid), + [{dummy1_h,false,State1},{dummy1_h,id,State2}] = lists:sort(Result3), + ok = sys:resume(Pid), ok = gen_event:stop(Pid), ok. @@ -998,4 +1002,11 @@ replace_state(Config) when is_list(Config) -> Replace3 = fun(_) -> exit(fail) end, [{dummy1_h,false,NState2}] = sys:replace_state(Pid, Replace3), [{dummy1_h,false,NState2}] = sys:get_state(Pid), + %% verify state replaced if process sys suspended + NState3 = "replaced again and again", + Replace4 = fun({dummy1_h,false,_}=S) -> setelement(3,S,NState3) end, + ok = sys:suspend(Pid), + [{dummy1_h,false,NState3}] = sys:replace_state(Pid, Replace4), + ok = sys:resume(Pid), + [{dummy1_h,false,NState3}] = sys:get_state(Pid), ok. diff --git a/lib/stdlib/test/gen_fsm_SUITE.erl b/lib/stdlib/test/gen_fsm_SUITE.erl index fd15838b7d..8aeec07ae8 100644 --- a/lib/stdlib/test/gen_fsm_SUITE.erl +++ b/lib/stdlib/test/gen_fsm_SUITE.erl @@ -426,6 +426,14 @@ get_state(Config) when is_list(Config) -> {idle, State} = sys:get_state(gfsm), {idle, State} = sys:get_state(gfsm, 5000), stop_it(Pid2), + + %% check that get_state works when pid is sys suspended + {ok, Pid3} = gen_fsm:start(gen_fsm_SUITE, {state_data, State}, []), + {idle, State} = sys:get_state(Pid3), + ok = sys:suspend(Pid3), + {idle, State} = sys:get_state(Pid3, 5000), + ok = sys:resume(Pid3), + stop_it(Pid3), ok. replace_state(Config) when is_list(Config) -> @@ -442,8 +450,18 @@ replace_state(Config) when is_list(Config) -> {state0, NState2} = sys:get_state(Pid), %% verify no change in state if replace function crashes Replace3 = fun(_) -> error(fail) end, - {state0, NState2} = sys:replace_state(Pid, Replace3), + {'EXIT',{{callback_failed, + {gen_fsm,system_replace_state},{error,fail}},_}} = + (catch sys:replace_state(Pid, Replace3)), {state0, NState2} = sys:get_state(Pid), + %% verify state replaced if process sys suspended + ok = sys:suspend(Pid), + Suffix2 = " and again", + NState3 = NState2 ++ Suffix2, + Replace4 = fun({StateName, _}) -> {StateName, NState3} end, + {state0, NState3} = sys:replace_state(Pid, Replace4), + ok = sys:resume(Pid), + {state0, NState3} = sys:get_state(Pid, 5000), stop_it(Pid), ok. diff --git a/lib/stdlib/test/gen_server_SUITE.erl b/lib/stdlib/test/gen_server_SUITE.erl index a360a0809b..960e7f60e7 100644 --- a/lib/stdlib/test/gen_server_SUITE.erl +++ b/lib/stdlib/test/gen_server_SUITE.erl @@ -1049,6 +1049,9 @@ get_state(Config) when is_list(Config) -> {ok, Pid} = gen_server:start_link(?MODULE, {state,State}, []), State = sys:get_state(Pid), State = sys:get_state(Pid, 5000), + ok = sys:suspend(Pid), + State = sys:get_state(Pid), + ok = sys:resume(Pid), ok. %% Verify that sys:replace_state correctly replaces gen_server state @@ -1075,8 +1078,18 @@ replace_state(Config) when is_list(Config) -> NState2 = sys:get_state(Pid, 5000), %% verify no change in state if replace function crashes Replace3 = fun(_) -> throw(fail) end, - NState2 = sys:replace_state(Pid, Replace3), + {'EXIT',{{callback_failed, + {gen_server,system_replace_state},{throw,fail}},_}} = + (catch sys:replace_state(Pid, Replace3)), NState2 = sys:get_state(Pid, 5000), + %% verify state replaced if process sys suspended + ok = sys:suspend(Pid), + Suffix2 = " and again", + NState3 = NState2 ++ Suffix2, + Replace4 = fun(S) -> S ++ Suffix2 end, + NState3 = sys:replace_state(Pid, Replace4), + ok = sys:resume(Pid), + NState3 = sys:get_state(Pid, 5000), ok. %% Test that the time for a huge message queue is not diff --git a/lib/stdlib/test/sys_SUITE.erl b/lib/stdlib/test/sys_SUITE.erl index c06ba545e7..f38bc87ae5 100644 --- a/lib/stdlib/test/sys_SUITE.erl +++ b/lib/stdlib/test/sys_SUITE.erl @@ -19,7 +19,7 @@ -module(sys_SUITE). -export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1, init_per_group/2,end_per_group/2,log/1,log_to_file/1, - stats/1,trace/1,suspend/1,install/1]). + stats/1,trace/1,suspend/1,install/1,special_process/1]). -export([handle_call/3,terminate/2,init/1]). -include_lib("test_server/include/test_server.hrl"). @@ -27,14 +27,12 @@ %% Doesn't look into change_code at all -%% Doesn't address writing your own process that understands -%% system messages at all. suite() -> [{ct_hooks,[ts_install_cth]}]. all() -> - [log, log_to_file, stats, trace, suspend, install]. + [log, log_to_file, stats, trace, suspend, install, special_process]. groups() -> []. @@ -157,6 +155,84 @@ install(Config) when is_list(Config) -> ?line stop(), ok. +special_process(suite) -> []; +special_process(Config) when is_list(Config) -> + ok = spec_proc(sys_sp1), + ok = spec_proc(sys_sp2). + +spec_proc(Mod) -> + {ok,_} = Mod:start_link(100), + ok = sys:statistics(Mod,true), + ok = sys:trace(Mod,true), + 1 = Ch = Mod:alloc(), + Free = lists:seq(2,100), + Replace = case sys:get_state(Mod) of + {[Ch],Free} -> + fun({A,F}) -> + Free = F, + {A,[2,3,4]} + end; + {state,[Ch],Free} -> + fun({state,A,F}) -> + Free = F, + {state,A,[2,3,4]} + end + end, + case sys:replace_state(Mod, Replace) of + {[Ch],[2,3,4]} -> ok; + {state,[Ch],[2,3,4]} -> ok + end, + ok = Mod:free(Ch), + case sys:get_state(Mod) of + {[],[1,2,3,4]} -> ok; + {state,[],[1,2,3,4]} -> ok + end, + {ok,[{start_time,_}, + {current_time,_}, + {reductions,_}, + {messages_in,2}, + {messages_out,1}]} = sys:statistics(Mod,get), + ok = sys:statistics(Mod,false), + [] = sys:replace_state(Mod, fun(_) -> [] end), + process_flag(trap_exit,true), + ok = case catch sys:get_state(Mod) of + [] -> + ok; + {'EXIT',{{callback_failed, + {Mod,system_get_state},{throw,fail}},_}} -> + ok + end, + Mod:stop(), + WaitForUnregister = fun W() -> + case whereis(Mod) of + undefined -> ok; + _ -> timer:sleep(10), W() + end + end, + WaitForUnregister(), + {ok,_} = Mod:start_link(4), + ok = case catch sys:replace_state(Mod, fun(_) -> {} end) of + {} -> + ok; + {'EXIT',{{callback_failed, + {Mod,system_replace_state},{throw,fail}},_}} -> + ok + end, + Mod:stop(), + WaitForUnregister(), + {ok,_} = Mod:start_link(4), + StateFun = fun(_) -> error(fail) end, + ok = case catch sys:replace_state(Mod, StateFun) of + {} -> + ok; + {'EXIT',{{callback_failed, + {Mod,system_replace_state},{error,fail}},_}} -> + ok; + {'EXIT',{{callback_failed,StateFun,{error,fail}},_}} -> + ok + end, + Mod:stop(). + %%%%%%%%%%%%%%%%%%%% %% Dummy server diff --git a/lib/stdlib/test/sys_sp1.erl b/lib/stdlib/test/sys_sp1.erl new file mode 100644 index 0000000000..e84ffcfa12 --- /dev/null +++ b/lib/stdlib/test/sys_sp1.erl @@ -0,0 +1,114 @@ +%% +%% %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(sys_sp1). +-export([start_link/1, stop/0]). +-export([alloc/0, free/1]). +-export([init/1]). +-export([system_continue/3, system_terminate/4, + write_debug/3, + system_get_state/1, system_replace_state/2]). + +%% Implements the ch4 example from the Design Principles doc. Same as +%% sys_sp2 except this module exports system_get_state/1 and +%% system_replace_state/2 + +start_link(NumCh) -> + proc_lib:start_link(?MODULE, init, [[self(),NumCh]]). + +stop() -> + ?MODULE ! stop, + ok. + +alloc() -> + ?MODULE ! {self(), alloc}, + receive + {?MODULE, Res} -> + Res + end. + +free(Ch) -> + ?MODULE ! {free, Ch}, + ok. + +init([Parent,NumCh]) -> + register(?MODULE, self()), + Chs = channels(NumCh), + Deb = sys:debug_options([]), + proc_lib:init_ack(Parent, {ok, self()}), + loop(Chs, Parent, Deb). + +loop(Chs, Parent, Deb) -> + receive + {From, alloc} -> + Deb2 = sys:handle_debug(Deb, fun write_debug/3, + ?MODULE, {in, alloc, From}), + {Ch, Chs2} = alloc(Chs), + From ! {?MODULE, Ch}, + Deb3 = sys:handle_debug(Deb2, fun write_debug/3, + ?MODULE, {out, {?MODULE, Ch}, From}), + loop(Chs2, Parent, Deb3); + {free, Ch} -> + Deb2 = sys:handle_debug(Deb, fun write_debug/3, + ?MODULE, {in, {free, Ch}}), + Chs2 = free(Ch, Chs), + loop(Chs2, Parent, Deb2); + {system, From, Request} -> + sys:handle_system_msg(Request, From, Parent, + ?MODULE, Deb, Chs); + stop -> + sys:handle_debug(Deb, fun write_debug/3, + ?MODULE, {in, stop}), + ok + end. + +system_continue(Parent, Deb, Chs) -> + loop(Chs, Parent, Deb). + +system_terminate(Reason, _Parent, _Deb, _Chs) -> + exit(Reason). + +system_get_state([]) -> + throw(fail); +system_get_state(Chs) -> + {ok, Chs}. + +system_replace_state(_StateFun, {}) -> + throw(fail); +system_replace_state(StateFun, Chs) -> + NChs = StateFun(Chs), + {ok, NChs, NChs}. + +write_debug(Dev, Event, Name) -> + io:format(Dev, "~p event = ~p~n", [Name, Event]). + +channels(NumCh) -> + {_Allocated=[], _Free=lists:seq(1,NumCh)}. + +alloc({_, []}) -> + {error, "no channels available"}; +alloc({Allocated, [H|T]}) -> + {H, {[H|Allocated], T}}. + +free(Ch, {Alloc, Free}=Channels) -> + case lists:member(Ch, Alloc) of + true -> + {lists:delete(Ch, Alloc), [Ch|Free]}; + false -> + Channels + end. diff --git a/lib/stdlib/test/sys_sp2.erl b/lib/stdlib/test/sys_sp2.erl new file mode 100644 index 0000000000..56a5e4d071 --- /dev/null +++ b/lib/stdlib/test/sys_sp2.erl @@ -0,0 +1,107 @@ +%% +%% %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(sys_sp2). +-export([start_link/1, stop/0]). +-export([alloc/0, free/1]). +-export([init/1]). +-export([system_continue/3, system_terminate/4, + write_debug/3]). + +%% Implements the ch4 example from the Design Principles doc. Same as +%% sys_sp1 except this module does not export system_get_state/1 or +%% system_replace_state/2 + +start_link(NumCh) -> + proc_lib:start_link(?MODULE, init, [[self(),NumCh]]). + +stop() -> + ?MODULE ! stop, + ok. + +alloc() -> + ?MODULE ! {self(), alloc}, + receive + {?MODULE, Res} -> + Res + end. + +free(Ch) -> + ?MODULE ! {free, Ch}, + ok. + +%% can't use 2-tuple for state here as we do in sys_sp1, since the 2-tuple +%% is not compatible with the backward compatibility handling for +%% sys:get_state in sys.erl +-record(state, {alloc,free}). + +init([Parent,NumCh]) -> + register(?MODULE, self()), + Chs = channels(NumCh), + Deb = sys:debug_options([]), + proc_lib:init_ack(Parent, {ok, self()}), + loop(Chs, Parent, Deb). + +loop(Chs, Parent, Deb) -> + receive + {From, alloc} -> + Deb2 = sys:handle_debug(Deb, fun write_debug/3, + ?MODULE, {in, alloc, From}), + {Ch, Chs2} = alloc(Chs), + From ! {?MODULE, Ch}, + Deb3 = sys:handle_debug(Deb2, fun write_debug/3, + ?MODULE, {out, {?MODULE, Ch}, From}), + loop(Chs2, Parent, Deb3); + {free, Ch} -> + Deb2 = sys:handle_debug(Deb, fun write_debug/3, + ?MODULE, {in, {free, Ch}}), + Chs2 = free(Ch, Chs), + loop(Chs2, Parent, Deb2); + {system, From, Request} -> + sys:handle_system_msg(Request, From, Parent, + ?MODULE, Deb, Chs); + stop -> + sys:handle_debug(Deb, fun write_debug/3, + ?MODULE, {in, stop}), + ok + end. + +system_continue(Parent, Deb, Chs) -> + loop(Chs, Parent, Deb). + +system_terminate(Reason, _Parent, _Deb, _Chs) -> + exit(Reason). + +write_debug(Dev, Event, Name) -> + io:format(Dev, "~p event = ~p~n", [Name, Event]). + +channels(NumCh) -> + #state{alloc=[], free=lists:seq(1,NumCh)}. + +alloc(#state{free=[]}=Channels) -> + {{error, "no channels available"}, Channels}; +alloc(#state{alloc=Allocated, free=[H|T]}) -> + {H, #state{alloc=[H|Allocated], free=T}}. + +free(Ch, #state{alloc=Alloc, free=Free}=Channels) -> + case lists:member(Ch, Alloc) of + true -> + #state{alloc=lists:delete(Ch, Alloc), free=[Ch|Free]}; + false -> + Channels + end. -- cgit v1.2.3