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|
%%% Copyright (c) 2019, Sunet.
%%% See LICENSE for licensing information.
%% A remote manager is a genserver for coordination of remotes for all
%% tokens.
%% Provide a lookup service for servers in need of a remote to send
%% requests to, by keeping track of which module is current for a
%% given vtoken and spawn a p11p_remote genserver "on demand".
%%
%% Provide a client event and a server event API for servers and
%% remotes, respectively, where events like "remote timed out" and
%% "p11 client hung up" can be reported.
%%
%% Keep track of successful p11 requests which might cause state
%% changes in a token, like logins. When switching token under the
%% feet of the p11 client, replay whatever is needed to the new
%% token. This includes the p11-kit RPC protocol version octet.
%% Certain state changing p11 requests cannot be replayed, like
%% generation of a new key. Any such (successful) request invalidates
%% all other remotes for the given vtoken.
-module(p11p_remote_manager).
-behaviour(gen_server).
%% API.
-export([start_link/0]).
-export([remote_for_token/1, client_event/2]). % For servers.
-export([server_event/2]). % For remotes.
%% Genserver callbacks.
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2,
code_change/3]).
%% Records and types.
-record(remote, {
tokname :: string(),
servid :: atom(),
modpath :: string(),
modenv :: [],
balance :: integer(),
pid :: pid() | undefined
}).
-record(token, {
mode :: p11p_config:token_mode_t(),
balance_count :: integer(),
remotes :: [#remote{}] % Active remote in hd().
}).
-record(state, {
tokens :: #{string() => #token{}}
}).
%% API implementation.
-spec start_link() -> {ok, pid()} | {error, term()}.
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
-spec remote_for_token(string()) -> pid().
remote_for_token(TokName) ->
gen_server:call(?MODULE, {remote_for_token, TokName}).
client_event(Event, Args) ->
gen_server:cast(?MODULE, {client_event, Event, Args}).
server_event(Event, Args) ->
gen_server:cast(?MODULE, {server_event, Event, Args}).
%% Genserver callbacks.
init([]) ->
{ok, #state{tokens = init_tokens(p11p_config:tokens())}}.
handle_call({remote_for_token, TokNameIn}, _, #state{tokens = Tokens} = S) ->
#{TokNameIn := TokenIn} = Tokens,
RemotesIn = TokenIn#token.remotes,
lager:debug("all remotes: ~p", [RemotesIn]),
{Remotes, BalanceCount} =
case TokenIn#token.balance_count of
0 ->
lager:debug("~p: balancing: next remote", [self()]),
Rotated = rotate_remotes(RemotesIn),
First = hd(Rotated),
{Rotated, First#remote.balance - 1};
N when N > 0 ->
lager:debug("~p: balancing: ~B more invocations", [self(), N]),
{RemotesIn, N - 1};
-1 ->
{RemotesIn, -1}
end,
#remote{tokname = TokNameIn,
servid = ServId,
modpath = ModPath,
modenv = ModEnv,
pid = PidIn} = SelectedRemote = hd(Remotes),
case PidIn of
undefined ->
{ok, Pid} =
p11p_remote:start_link(ServId, TokNameIn, ModPath, ModEnv),
Remote = SelectedRemote#remote{pid = Pid},
Token = TokenIn#token{remotes = [Remote | tl(Remotes)],
balance_count = BalanceCount},
{reply, Pid, S#state{tokens = Tokens#{TokNameIn := Token}}};
_ ->
{reply, PidIn, S}
end;
handle_call(Call, _From, State) ->
lager:debug("Unhandled call: ~p~n", [Call]),
{reply, unhandled, State}.
handle_cast({server_event, timeout, [TokNameIn, Server]},
#state{tokens = Tokens} = S) ->
lager:debug("~p: ~s: timed out, stopping ~p", [self(), TokNameIn, Server]),
gen_server:stop(Server), % Hang up on p11 client.
%% TODO: do some code dedup with remote_for_token?
#{TokNameIn := TokenIn} = Tokens,
Remotes = TokenIn#token.remotes,
SelectedRemote = hd(Remotes),
Remote = SelectedRemote#remote{pid = undefined},
Token = TokenIn#token{remotes = tl(Remotes) ++ [Remote]},
lager:debug("~p: ~s: updated token: ~p", [self(), TokNameIn, Token]),
{noreply, S#state{tokens = Tokens#{TokNameIn := Token}}};
handle_cast({client_event, client_gone, [TokName, Pid]},
#state{tokens = Tokens} = S) ->
lager:debug("~p: asking remote ~p to stop", [self(), Pid]),
p11p_remote:stop(Pid, normal),
#{TokName := TokenIn} = Tokens,
Remotes = lists:map(fun(E) ->
case E#remote.pid of
Pid -> E#remote{pid = undefined};
_ -> E
end
end, TokenIn#token.remotes),
Token = TokenIn#token{remotes = Remotes},
{noreply, S#state{tokens = Tokens#{TokName := Token}}};
handle_cast(Cast, State) ->
lager:debug("Unhandled cast: ~p~n", [Cast]),
{noreply, State}.
handle_info({Port, {exit_status, Status}}, State) ->
%% FIXME: do we need to be trapping exits explicitly?
lager:info("~p: process ~p exited with ~p", [self(), Port, Status]),
{noreply, State};
handle_info(Info, State) ->
lager:debug("~p: Unhandled info: ~p~n", [self(), Info]),
{noreply, State}.
terminate(_Reason, _State) ->
ok.
code_change(_OldVersion, State, _Extra) ->
{ok, State}.
%% Private functions
-spec init_tokens([p11p_config:token()]) -> #{string() => #token{}}.
init_tokens(ConfTokens) ->
init_tokens(ConfTokens, #{}).
init_tokens([], Acc)->
lager:debug("~p: created tokens from config: ~p", [self(), Acc]),
Acc;
init_tokens([H|T], Acc)->
init_tokens(T, Acc#{p11p_config:nameof(H) => new_token(H)}).
new_token(Conf) ->
Name = p11p_config:nameof(Conf),
Mode = p11p_config:token_mode(Name),
Remotes = remotes(Name,
p11p_config:modules_for_token(Name),
Mode),
R0 = hd(Remotes),
#token{
mode = p11p_config:token_mode(Name),
balance_count = R0#remote.balance,
remotes = Remotes
}.
remotes(TokName, ConfModules, ConfMode) ->
remotes(TokName, ConfModules, ConfMode, []).
remotes(_, [], _, Acc) ->
Acc;
remotes(TokName, [H|T], ConfMode, Acc) ->
ModName = p11p_config:nameof(H),
ServName = "p11p_remote:" ++ TokName ++ ":" ++ ModName,
ModPath = p11p_config:module_path(H),
ModEnv = p11p_config:module_env(H),
remotes(TokName, T, ConfMode, [#remote{
tokname = TokName,
servid = list_to_atom(ServName),
modpath = ModPath,
modenv = ModEnv,
balance = balance(ConfMode, length(T) + 1)
}
| Acc]).
-spec balance(p11p_config:token_mode_t(), non_neg_integer()) -> integer().
balance({balance, Ratios}, N) ->
lists:nth(N, Ratios);
balance(_, _) ->
-1.
%% -spec balance_count(p11p_config:token_mode_t()) -> integer().
%% balance_count(#token{mode = {balance, _}, balance_count = C}) ->
%% C - 1;
%% balance_count(_) ->
%% -1.
rotate_remotes(L) ->
lists:reverse([hd(L) | lists:reverse(tl(L))]).
|
