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% 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
% 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.
-module(couch_peruser).
-behaviour(gen_server).
-include_lib("couch/include/couch_db.hrl").
-define(USERDB_PREFIX, "userdb-").
% gen_server callbacks
-export([start_link/0, init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-export([init_changes_handler/1, changes_handler/3]).
-record(state, {parent, db_name, delete_dbs, changes_pid, changes_ref}).
-define(RELISTEN_DELAY, 5000).
start_link() ->
gen_server:start_link(?MODULE, [], []).
init() ->
case config:get_boolean("couch_peruser", "enable", false) of
false ->
#state{};
true ->
DbName = ?l2b(config:get(
"couch_httpd_auth", "authentication_db", "_users")),
DeleteDbs = config:get_boolean("couch_peruser", "delete_dbs", false),
State = #state{parent = self(),
db_name = DbName,
delete_dbs = DeleteDbs},
{Pid, Ref} = spawn_opt(
?MODULE, init_changes_handler, [State], [link, monitor]),
State#state{changes_pid=Pid, changes_ref=Ref}
end.
init_changes_handler(#state{db_name=DbName} = State) ->
try
{ok, Db} = couch_db:open_int(DbName, [?ADMIN_CTX, sys_db]),
FunAcc = {fun ?MODULE:changes_handler/3, State},
(couch_changes:handle_db_changes(
#changes_args{feed="continuous", timeout=infinity},
{json_req, null},
Db))(FunAcc)
catch error:database_does_not_exist ->
ok
end.
changes_handler({change, {Doc}, _Prepend}, _ResType, State=#state{}) ->
case couch_util:get_value(<<"id">>, Doc) of
<<"org.couchdb.user:",User/binary>> ->
case couch_util:get_value(<<"deleted">>, Doc, false) of
false ->
UserDb = ensure_user_db(User),
ok = ensure_security(User, UserDb, fun add_user/3),
State;
true ->
case State#state.delete_dbs of
true ->
_UserDb = delete_user_db(User),
State;
false ->
UserDb = user_db_name(User),
ok = ensure_security(User, UserDb, fun remove_user/3),
State
end
end;
_ ->
State
end;
changes_handler(_Event, _ResType, State) ->
State.
delete_user_db(User) ->
UserDb = user_db_name(User),
try
case fabric:delete_db(UserDb, [?ADMIN_CTX]) of
ok -> ok;
accepted -> ok
end
catch error:database_does_not_exist ->
ok
end,
UserDb.
ensure_user_db(User) ->
UserDb = user_db_name(User),
try
{ok, _DbInfo} = fabric:get_db_info(UserDb)
catch error:database_does_not_exist ->
case fabric:create_db(UserDb, [?ADMIN_CTX]) of
ok -> ok;
accepted -> ok
end
end,
UserDb.
add_user(User, Prop, {Modified, SecProps}) ->
{PropValue} = couch_util:get_value(Prop, SecProps, {[]}),
Names = couch_util:get_value(<<"names">>, PropValue, []),
case lists:member(User, Names) of
true ->
{Modified, SecProps};
false ->
{true,
lists:keystore(
Prop, 1, SecProps,
{Prop,
{lists:keystore(
<<"names">>, 1, PropValue,
{<<"names">>, [User | Names]})}})}
end.
remove_user(User, Prop, {Modified, SecProps}) ->
{PropValue} = couch_util:get_value(Prop, SecProps, {[]}),
Names = couch_util:get_value(<<"names">>, PropValue, []),
case lists:member(User, Names) of
false ->
{Modified, SecProps};
true ->
{true,
lists:keystore(
Prop, 1, SecProps,
{Prop,
{lists:keystore(
<<"names">>, 1, PropValue,
{<<"names">>, lists:delete(User, Names)})}})}
end.
ensure_security(User, UserDb, TransformFun) ->
{ok, Shards} = fabric:get_all_security(UserDb, [?ADMIN_CTX]),
{_ShardInfo, {SecProps}} = hd(Shards),
% assert that shards have the same security object
true = lists:all(fun ({_, {SecProps1}}) ->
SecProps =:= SecProps1
end, Shards),
case lists:foldl(
fun (Prop, SAcc) -> TransformFun(User, Prop, SAcc) end,
{false, SecProps},
[<<"admins">>, <<"members">>]) of
{false, _} ->
ok;
{true, SecProps1} ->
ok = fabric:set_security(UserDb, {SecProps1}, [?ADMIN_CTX])
end.
user_db_name(User) ->
HexUser = list_to_binary(
[string:to_lower(integer_to_list(X, 16)) || <<X>> <= User]),
<<?USERDB_PREFIX,HexUser/binary>>.
%% gen_server callbacks
init([]) ->
ok = subscribe_for_changes(),
{ok, init()}.
handle_call(_Msg, _From, State) ->
{reply, error, State}.
handle_cast(update_config, State) when State#state.changes_pid =/= undefined ->
% we don't want to have multiple changes handler at the same time
demonitor(State#state.changes_ref, [flush]),
exit(State#state.changes_pid, kill),
{noreply, init()};
handle_cast(update_config, _State) ->
{noreply, init()};
handle_cast(stop, State) ->
{stop, normal, State};
handle_cast(_Msg, State) ->
{noreply, State}.
handle_info({'DOWN', Ref, _, _, _Reason}, #state{changes_ref=Ref} = State) ->
{stop, normal, State};
handle_info({config_change, "couch_peruser", _, _, _}, State) ->
handle_cast(update_config, State);
handle_info({config_change, "couch_httpd_auth", "authentication_db", _, _}, State) ->
handle_cast(update_config, State);
handle_info({gen_event_EXIT, _Handler, _Reason}, State) ->
erlang:send_after(?RELISTEN_DELAY, self(), restart_config_listener),
{noreply, State};
handle_info({'EXIT', _Pid, _Reason}, State) ->
erlang:send_after(?RELISTEN_DELAY, self(), restart_config_listener),
{noreply, State};
handle_info(restart_config_listener, State) ->
ok = subscribe_for_changes(),
{noreply, State};
handle_info(_Msg, State) ->
{noreply, State}.
subscribe_for_changes() ->
config:subscribe_for_changes([
{"couch_httpd_auth", "authentication_db"},
"couch_peruser"
]).
terminate(_Reason, _State) ->
%% Everything should be linked or monitored, let nature
%% take its course.
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
|
