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+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 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.
+%% You may obtain a copy of the License at
+%5
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% 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.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(persistent_term_SUITE).
+-include_lib("common_test/include/ct.hrl").
+
+-export([all/0,suite/0,
+ basic/1,purging/1,sharing/1,get_trapping/1,
+ info/1,info_trapping/1,killed_while_trapping/1,
+ off_heap_values/1,keys/1,collisions/1,
+ init_restart/1]).
+
+%%
+-export([test_init_restart_cmd/1]).
+
+suite() ->
+ [{ct_hooks,[ts_install_cth]},
+ {timetrap,{minutes,10}}].
+
+all() ->
+ [basic,purging,sharing,get_trapping,info,info_trapping,
+ killed_while_trapping,off_heap_values,keys,collisions,
+ init_restart].
+
+basic(_Config) ->
+ Chk = chk(),
+ N = 777,
+ Seq = lists:seq(1, N),
+ par(2, N, Seq),
+ seq(3, Seq),
+ seq(3, Seq), %Same values.
+ _ = [begin
+ Key = {?MODULE,{key,I}},
+ true = persistent_term:erase(Key),
+ false = persistent_term:erase(Key),
+ {'EXIT',{badarg,_}} = (catch persistent_term:get(Key))
+ end || I <- Seq],
+ [] = [P || {{?MODULE,_},_}=P <- persistent_term:get()],
+ chk(Chk).
+
+par(C, N, Seq) ->
+ _ = [spawn_link(fun() ->
+ ok = persistent_term:put({?MODULE,{key,I}},
+ {value,C*I})
+ end) || I <- Seq],
+ Result = wait(N),
+ _ = [begin
+ Double = C*I,
+ {{?MODULE,{key,I}},{value,Double}} = Res
+ end || {I,Res} <- lists:zip(Seq, Result)],
+ ok.
+
+seq(C, Seq) ->
+ _ = [ok = persistent_term:put({?MODULE,{key,I}}, {value,C*I}) ||
+ I <- Seq],
+ All = persistent_term:get(),
+ All = [P || {{?MODULE,_},_}=P <- persistent_term:get()],
+ All = [{Key,persistent_term:get(Key)} || {Key,_} <- All],
+ Result = lists:sort(All),
+ _ = [begin
+ Double = C*I,
+ {{?MODULE,{key,I}},{value,Double}} = Res
+ end || {I,Res} <- lists:zip(Seq, Result)],
+ ok.
+
+wait(N) ->
+ All = [P || {{?MODULE,_},_}=P <- persistent_term:get()],
+ case length(All) of
+ N ->
+ All = [{Key,persistent_term:get(Key)} || {Key,_} <- All],
+ lists:sort(All);
+ _ ->
+ receive after 10 -> ok end,
+ wait(N)
+ end.
+
+%% Make sure that terms that have been erased are copied into all
+%% processes that still hold a pointer to them.
+
+purging(_Config) ->
+ Chk = chk(),
+ do_purging(fun(K) -> persistent_term:put(K, {?MODULE,new}) end,
+ replaced),
+ do_purging(fun persistent_term:erase/1, erased),
+ chk(Chk).
+
+do_purging(Eraser, Type) ->
+ Parent = self(),
+ Key = {?MODULE,?FUNCTION_NAME},
+ ok = persistent_term:put(Key, {term,[<<"abc",0:777/unit:8>>]}),
+ Ps0 = [spawn_monitor(fun() -> purging_tester(Parent, Key) end) ||
+ _ <- lists:seq(1, 50)],
+ Ps = maps:from_list(Ps0),
+ purging_recv(gotten, Ps),
+ Eraser(Key),
+ _ = [P ! {Parent,Type} || P <- maps:keys(Ps)],
+ purging_wait(Ps).
+
+purging_recv(Tag, Ps) when map_size(Ps) > 0 ->
+ receive
+ {Pid,Tag} ->
+ true = is_map_key(Pid, Ps),
+ purging_recv(Tag, maps:remove(Pid, Ps))
+ end;
+purging_recv(_, _) -> ok.
+
+purging_wait(Ps) when map_size(Ps) > 0 ->
+ receive
+ {'DOWN',Ref,process,Pid,Reason} ->
+ normal = Reason,
+ Ref = map_get(Pid, Ps),
+ purging_wait(maps:remove(Pid, Ps))
+ end;
+purging_wait(_) -> ok.
+
+purging_tester(Parent, Key) ->
+ Term = persistent_term:get(Key),
+ purging_check_term(Term),
+ 0 = erts_debug:size_shared(Term),
+ Parent ! {self(),gotten},
+ receive
+ {Parent,erased} ->
+ {'EXIT',{badarg,_}} = (catch persistent_term:get(Key)),
+ purging_tester_1(Term);
+ {Parent,replaced} ->
+ {?MODULE,new} = persistent_term:get(Key),
+ purging_tester_1(Term)
+ end.
+
+%% Wait for the term to be copied into this process.
+purging_tester_1(Term) ->
+ purging_check_term(Term),
+ receive after 1 -> ok end,
+ case erts_debug:size_shared(Term) of
+ 0 ->
+ purging_tester_1(Term);
+ Size ->
+ %% The term has been copied into this process.
+ purging_check_term(Term),
+ Size = erts_debug:size(Term)
+ end.
+
+purging_check_term({term,[<<"abc",0:777/unit:8>>]}) ->
+ ok.
+
+%% Test that sharing is preserved when storing terms.
+
+sharing(_Config) ->
+ Chk = chk(),
+ Depth = 10,
+ Size = 2*Depth,
+ Shared = lists:foldl(fun(_, A) -> [A|A] end,
+ [], lists:seq(1, Depth)),
+ Size = erts_debug:size(Shared),
+ Key = {?MODULE,?FUNCTION_NAME},
+ ok = persistent_term:put(Key, Shared),
+ SharedStored = persistent_term:get(Key),
+ Size = erts_debug:size(SharedStored),
+ 0 = erts_debug:size_shared(SharedStored),
+
+ {Pid,Ref} = spawn_monitor(fun() ->
+ Term = persistent_term:get(Key),
+ Size = erts_debug:size(Term),
+ 0 = erts_debug:size_shared(Term),
+ true = Term =:= SharedStored
+ end),
+ receive
+ {'DOWN',Ref,process,Pid,normal} ->
+ true = persistent_term:erase(Key),
+ Size = erts_debug:size(SharedStored),
+ chk(Chk)
+ end.
+
+%% Test trapping of persistent_term:get/0.
+
+get_trapping(_Config) ->
+ Chk = chk(),
+
+ %% Assume that the get/0 traps after 4000 iterations
+ %% in a non-debug emulator.
+ N = case test_server:timetrap_scale_factor() of
+ 1 -> 10000;
+ _ -> 1000
+ end,
+ spawn_link(fun() -> get_trapping_create(N) end),
+ All = do_get_trapping(N, []),
+ N = get_trapping_check_result(lists:sort(All), 1),
+ erlang:garbage_collect(),
+ get_trapping_erase(N),
+ chk(Chk).
+
+do_get_trapping(N, Prev) ->
+ case persistent_term:get() of
+ Prev when length(Prev) >= N ->
+ All = [P || {{?MODULE,{get_trapping,_}},_}=P <- Prev],
+ case length(All) of
+ N -> All;
+ _ -> do_get_trapping(N, Prev)
+ end;
+ New ->
+ receive after 1 -> ok end,
+ do_get_trapping(N, New)
+ end.
+
+get_trapping_create(0) ->
+ ok;
+get_trapping_create(N) ->
+ ok = persistent_term:put({?MODULE,{get_trapping,N}}, N),
+ get_trapping_create(N-1).
+
+get_trapping_check_result([{{?MODULE,{get_trapping,N}},N}|T], N) ->
+ get_trapping_check_result(T, N+1);
+get_trapping_check_result([], N) -> N-1.
+
+get_trapping_erase(0) ->
+ ok;
+get_trapping_erase(N) ->
+ true = persistent_term:erase({?MODULE,{get_trapping,N}}),
+ get_trapping_erase(N-1).
+
+%% Test retrieving information about persistent terms.
+
+info(_Config) ->
+ Chk = chk(),
+
+ %% White box test of info/0.
+ N = 100,
+ try
+ Overhead = info_literal_area_overhead(),
+ io:format("Overhead = ~p\n", [Overhead]),
+ info_wb(N, Overhead, info_info())
+ after
+ _ = [_ = persistent_term:erase({?MODULE,I}) ||
+ I <- lists:seq(1, N)]
+ end,
+
+ chk(Chk).
+
+%% White box test of persistent_term:info/0. We take into account
+%% that there might already exist persistent terms (created by the
+%% OTP standard libraries), but we assume that they are not
+%% changed during the execution of this test case.
+
+info_wb(0, _, _) ->
+ ok;
+info_wb(N, Overhead, {BaseCount,BaseMemory}) ->
+ Key = {?MODULE,N},
+ Value = lists:seq(1, N),
+ ok = persistent_term:put(Key, Value),
+
+ %% Calculate the extra memory needed for this term.
+ WordSize = erlang:system_info(wordsize),
+ ExtraMemory = Overhead + 2 * N * WordSize,
+
+ %% Call persistent_term:info/0.
+ {Count,Memory} = info_info(),
+
+ %% There should be one more persistent term.
+ Count = BaseCount + 1,
+
+ %% Verify that the amount of memory is correct.
+ case BaseMemory + ExtraMemory of
+ Memory ->
+ %% Exactly right. The size of the hash table was not changed.
+ ok;
+ Expected ->
+ %% The size of the hash table has been doubled to avoid filling
+ %% the table to more than 50 percent. The previous number
+ %% of entries must have been exactly half the size of the
+ %% hash table. The expected number of extra words added by
+ %% the resizing will be twice that number.
+ ExtraWords = BaseCount * 2,
+ true = ExtraWords * WordSize =:= (Memory - Expected)
+ end,
+ info_wb(N-1, Overhead, {Count,Memory}).
+
+info_info() ->
+ #{count:=Count,memory:=Memory} = persistent_term:info(),
+ true = is_integer(Count) andalso Count >= 0,
+ true = is_integer(Memory) andalso Memory >= 0,
+ {Count,Memory}.
+
+%% Calculate the number of extra bytes needed for storing each term in
+%% the literal, assuming that the key is a tuple of size 2 with
+%% immediate elements. The calculated number is the size of the
+%% ErtsLiteralArea struct excluding the storage for the literal term
+%% itself.
+
+info_literal_area_overhead() ->
+ Key1 = {?MODULE,1},
+ Key2 = {?MODULE,2},
+ #{memory:=Mem0} = persistent_term:info(),
+ ok = persistent_term:put(Key1, literal),
+ #{memory:=Mem1} = persistent_term:info(),
+ ok = persistent_term:put(Key2, literal),
+ #{memory:=Mem2} = persistent_term:info(),
+ true = persistent_term:erase(Key1),
+ true = persistent_term:erase(Key2),
+
+ %% The size of the hash table may have doubled when inserting
+ %% one of the keys. To avoiding counting the change in the hash
+ %% table size, take the smaller size increase.
+ min(Mem2-Mem1, Mem1-Mem0).
+
+%% Test trapping of persistent_term:info/0.
+
+info_trapping(_Config) ->
+ Chk = chk(),
+
+ %% Assume that the info/0 traps after 4000 iterations
+ %% in a non-debug emulator.
+ N = case test_server:timetrap_scale_factor() of
+ 1 -> 10000;
+ _ -> 1000
+ end,
+ spawn_link(fun() -> info_trapping_create(N) end),
+ All = do_info_trapping(N, 0),
+ N = info_trapping_check_result(lists:sort(All), 1),
+ erlang:garbage_collect(),
+ info_trapping_erase(N),
+ chk(Chk).
+
+do_info_trapping(N, PrevMem) ->
+ case info_info() of
+ {N,Mem} ->
+ true = Mem >= PrevMem,
+ All = [P || {{?MODULE,{info_trapping,_}},_}=P <- persistent_term:get()],
+ case length(All) of
+ N -> All;
+ _ -> do_info_trapping(N, PrevMem)
+ end;
+ {_,Mem} ->
+ true = Mem >= PrevMem,
+ receive after 1 -> ok end,
+ do_info_trapping(N, Mem)
+ end.
+
+info_trapping_create(0) ->
+ ok;
+info_trapping_create(N) ->
+ ok = persistent_term:put({?MODULE,{info_trapping,N}}, N),
+ info_trapping_create(N-1).
+
+info_trapping_check_result([{{?MODULE,{info_trapping,N}},N}|T], N) ->
+ info_trapping_check_result(T, N+1);
+info_trapping_check_result([], N) -> N-1.
+
+info_trapping_erase(0) ->
+ ok;
+info_trapping_erase(N) ->
+ true = persistent_term:erase({?MODULE,{info_trapping,N}}),
+ info_trapping_erase(N-1).
+
+%% Test that hash tables are deallocated if a process running
+%% persistent_term:get/0 is killed.
+
+killed_while_trapping(_Config) ->
+ Chk = chk(),
+ N = case test_server:timetrap_scale_factor() of
+ 1 -> 20000;
+ _ -> 2000
+ end,
+ kwt_put(N),
+ kwt_spawn(10),
+ kwt_erase(N),
+ chk(Chk).
+
+kwt_put(0) ->
+ ok;
+kwt_put(N) ->
+ ok = persistent_term:put({?MODULE,{kwt,N}}, N),
+ kwt_put(N-1).
+
+kwt_spawn(0) ->
+ ok;
+kwt_spawn(N) ->
+ Pids = [spawn(fun kwt_getter/0) || _ <- lists:seq(1, 20)],
+ erlang:yield(),
+ _ = [exit(Pid, kill) || Pid <- Pids],
+ kwt_spawn(N-1).
+
+kwt_getter() ->
+ _ = persistent_term:get(),
+ kwt_getter().
+
+kwt_erase(0) ->
+ ok;
+kwt_erase(N) ->
+ true = persistent_term:erase({?MODULE,{kwt,N}}),
+ kwt_erase(N-1).
+
+%% Test storing off heap values (such as ref-counted binaries).
+
+off_heap_values(_Config) ->
+ Chk = chk(),
+ Key = {?MODULE,?FUNCTION_NAME},
+ Val = {a,list_to_binary(lists:seq(0, 255)),make_ref(),fun() -> ok end},
+ ok = persistent_term:put(Key, Val),
+ FetchedVal = persistent_term:get(Key),
+ Val = FetchedVal,
+ true = persistent_term:erase(Key),
+ off_heap_values_wait(FetchedVal, Val),
+ chk(Chk).
+
+off_heap_values_wait(FetchedVal, Val) ->
+ case erts_debug:size_shared(FetchedVal) of
+ 0 ->
+ Val = FetchedVal,
+ ok;
+ _ ->
+ erlang:yield(),
+ off_heap_values_wait(FetchedVal, Val)
+ end.
+
+%% Test some more data types as keys. Use the module name as a key
+%% to minimize the risk of collision with any key used
+%% by the OTP libraries.
+
+keys(_Config) ->
+ Chk = chk(),
+ do_key(?MODULE),
+ do_key([?MODULE]),
+ do_key(?MODULE_STRING),
+ do_key(list_to_binary(?MODULE_STRING)),
+ chk(Chk).
+
+do_key(Key) ->
+ Val = term_to_binary(Key),
+ ok = persistent_term:put(Key, Val),
+ StoredVal = persistent_term:get(Key),
+ Val = StoredVal,
+ true = persistent_term:erase(Key).
+
+%% Create persistent terms with keys that are known to collide.
+%% Delete them in random order, making sure that all others
+%% terms can still be found.
+
+collisions(_Config) ->
+ Chk = chk(),
+
+ %% Create persistent terms with random keys.
+ Keys = lists:flatten(colliding_keys()),
+ Kvs = [{K,rand:uniform(1000)} || K <- Keys],
+ _ = [ok = persistent_term:put(K, V) || {K,V} <- Kvs],
+ _ = [V = persistent_term:get(K) || {K,V} <- Kvs],
+
+ %% Now delete the persistent terms in random order.
+ collisions_delete(lists:keysort(2, Kvs)),
+
+ chk(Chk).
+
+collisions_delete([{Key,Val}|Kvs]) ->
+ Val = persistent_term:get(Key),
+ true = persistent_term:erase(Key),
+ true = lists:sort(persistent_term:get()) =:= lists:sort(Kvs),
+ _ = [V = persistent_term:get(K) || {K,V} <- Kvs],
+ collisions_delete(Kvs);
+collisions_delete([]) ->
+ ok.
+
+colliding_keys() ->
+ %% Collisions found by Jesper L. Andersen for breaking maps.
+ L = [[764492191,2361333849],
+ [49527266765044,90940896816021,20062927283041,267080852079651],
+ [249858369443708,206247021789428,20287304470696,25847120931175],
+ [10645228898670,224705626119556,267405565521452,258214397180678],
+ [264783762221048,166955943492306,98802957003141,102012488332476],
+ [69425677456944,177142907243411,137138950917722,228865047699598],
+ [116031213307147,29203342183358,37406949328742,255198080174323],
+ [200358182338308,235207156008390,120922906095920,116215987197289],
+ [58728890318426,68877471005069,176496507286088,221041411345780],
+ [91094120814795,50665258299931,256093108116737,19777509566621],
+ [74646746200247,98350487270564,154448261001199,39881047281135],
+ [23408943649483,164410325820923,248161749770122,274558342231648],
+ [169531547115055,213630535746863,235098262267796,200508473898303],
+ [235098564415817,85039146398174,51721575960328,173069189684390],
+ [176136386396069,155368359051606,147817099696487,265419485459634],
+ [137542881551462,40028925519736,70525669519846,63445773516557],
+ [173854695142814,114282444507812,149945832627054,99605565798831],
+ [177686773562184,127158716984798,132495543008547],
+ [227073396444896,139667311071766,158915951283562],
+ [26212438434289,94902985796531,198145776057315],
+ [266279278943923,58550737262493,74297973216378],
+ [32373606512065,131854353044428,184642643042326],
+ [34335377662439,85341895822066,273492717750246]],
+
+ %% Verify that the keys still collide (this will fail if the
+ %% internal hash function has been changed).
+ erts_debug:set_internal_state(available_internal_state, true),
+ try
+ case erlang:system_info(wordsize) of
+ 8 ->
+ verify_colliding_keys(L);
+ 4 ->
+ %% Not guaranteed to collide on a 32-bit system.
+ ok
+ end
+ after
+ erts_debug:set_internal_state(available_internal_state, false)
+ end,
+
+ L.
+
+verify_colliding_keys([[K|Ks]|Gs]) ->
+ Hash = internal_hash(K),
+ [Hash] = lists:usort([internal_hash(Key) || Key <- Ks]),
+ verify_colliding_keys(Gs);
+verify_colliding_keys([]) ->
+ ok.
+
+internal_hash(Term) ->
+ erts_debug:get_internal_state({internal_hash,Term}).
+
+%% Test that all persistent terms are erased by init:restart/0.
+
+init_restart(_Config) ->
+ File = "command_file",
+ ok = file:write_file(File, term_to_binary(restart)),
+ {ok,[[Erl]]} = init:get_argument(progname),
+ ModPath = filename:dirname(code:which(?MODULE)),
+ Cmd = Erl ++ " -pa " ++ ModPath ++ " -noshell "
+ "-run " ++ ?MODULE_STRING ++ " test_init_restart_cmd " ++
+ File,
+ io:format("~s\n", [Cmd]),
+ Expected = "12ok",
+ case os:cmd(Cmd) of
+ Expected ->
+ ok;
+ Actual ->
+ io:format("Expected: ~s", [Expected]),
+ io:format("Actual: ~s\n", [Actual]),
+ ct:fail(unexpected_output)
+ end.
+
+test_init_restart_cmd([File]) ->
+ try
+ do_test_init_restart_cmd(File)
+ catch
+ C:R ->
+ io:format("\n~p ~p\n", [C,R]),
+ halt()
+ end,
+ receive
+ _ -> ok
+ end.
+
+do_test_init_restart_cmd(File) ->
+ {ok,Bin} = file:read_file(File),
+ Seq = lists:seq(1, 50),
+ case binary_to_term(Bin) of
+ restart ->
+ _ = [persistent_term:put({?MODULE,I}, {value,I}) ||
+ I <- Seq],
+ ok = file:write_file(File, term_to_binary(was_restarted)),
+ io:put_chars("1"),
+ init:restart(),
+ receive
+ _ -> ok
+ end;
+ was_restarted ->
+ io:put_chars("2"),
+ ok = file:delete(File),
+ _ = [begin
+ Key = {?MODULE,I},
+ {'EXIT',{badarg,_}} = (catch persistent_term:get(Key))
+ end || I <- Seq],
+ io:put_chars("ok"),
+ init:stop()
+ end.
+
+%% Check that there is the same number of persistents terms before
+%% and after each test case.
+
+chk() ->
+ persistent_term:info().
+
+chk(Chk) ->
+ Chk = persistent_term:info(),
+ Key = {?MODULE,?FUNCTION_NAME},
+ ok = persistent_term:put(Key, {term,Chk}),
+ Term = persistent_term:get(Key),
+ true = persistent_term:erase(Key),
+ chk_not_stuck(Term),
+ ok.
+
+chk_not_stuck(Term) ->
+ %% Hash tables to be deleted are put onto a queue.
+ %% Make sure that the queue isn't stuck by a table with
+ %% a non-zero ref count.
+
+ case erts_debug:size_shared(Term) of
+ 0 ->
+ erlang:yield(),
+ chk_not_stuck(Term);
+ _ ->
+ ok
+ end.