1 files changed, 410 insertions, 0 deletions
diff --git a/apps/couch/src/couch_auth_cache.erl b/apps/couch/src/couch_auth_cache.erl
new file mode 100644
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+++ b/apps/couch/src/couch_auth_cache.erl
@@ -0,0 +1,410 @@
+% 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_auth_cache).
+-behaviour(gen_server).
+
+% public API
+-export([get_user_creds/1]).
+
+% gen_server API
+-export([start_link/0, init/1, handle_call/3, handle_info/2, handle_cast/2]).
+-export([code_change/3, terminate/2]).
+
+-include("couch_db.hrl").
+-include("couch_js_functions.hrl").
+
+-define(STATE, auth_state_ets).
+-define(BY_USER, auth_by_user_ets).
+-define(BY_ATIME, auth_by_atime_ets).
+
+-record(state, {
+    max_cache_size = 0,
+    cache_size = 0,
+    db_notifier = nil
+}).
+
+
+-spec get_user_creds(UserName::string() | binary()) ->
+    Credentials::list() | nil.
+
+get_user_creds(UserName) when is_list(UserName) ->
+    get_user_creds(?l2b(UserName));
+
+get_user_creds(UserName) ->
+    UserCreds = case couch_config:get("admins", ?b2l(UserName)) of
+    "-hashed-" ++ HashedPwdAndSalt ->
+        % the name is an admin, now check to see if there is a user doc
+        % which has a matching name, salt, and password_sha
+        [HashedPwd, Salt] = string:tokens(HashedPwdAndSalt, ","),
+        case get_from_cache(UserName) of
+        nil ->
+            [{<<"roles">>, [<<"_admin">>]},
+                {<<"salt">>, ?l2b(Salt)},
+                {<<"password_sha">>, ?l2b(HashedPwd)}];
+        UserProps when is_list(UserProps) ->
+            DocRoles = couch_util:get_value(<<"roles">>, UserProps),
+            [{<<"roles">>, [<<"_admin">> | DocRoles]},
+                {<<"salt">>, ?l2b(Salt)},
+                {<<"password_sha">>, ?l2b(HashedPwd)}]
+        end;
+    _Else ->
+        get_from_cache(UserName)
+    end,
+    validate_user_creds(UserCreds).
+
+
+get_from_cache(UserName) ->
+    exec_if_auth_db(
+        fun(_AuthDb) ->
+            maybe_refresh_cache(),
+            case ets:lookup(?BY_USER, UserName) of
+            [] ->
+                gen_server:call(?MODULE, {fetch, UserName}, infinity);
+            [{UserName, {Credentials, _ATime}}] ->
+                couch_stats_collector:increment({couchdb, auth_cache_hits}),
+                gen_server:cast(?MODULE, {cache_hit, UserName}),
+                Credentials
+            end
+        end,
+        nil
+    ).
+
+
+validate_user_creds(nil) ->
+    nil;
+validate_user_creds(UserCreds) ->
+    case couch_util:get_value(<<"_conflicts">>, UserCreds) of
+    undefined ->
+        ok;
+    _ConflictList ->
+        throw({unauthorized,
+            <<"User document conflicts must be resolved before the document",
+              " is used for authentication purposes.">>
+        })
+    end,
+    UserCreds.
+
+
+start_link() ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+
+
+init(_) ->
+    ?STATE = ets:new(?STATE, [set, protected, named_table]),
+    ?BY_USER = ets:new(?BY_USER, [set, protected, named_table]),
+    ?BY_ATIME = ets:new(?BY_ATIME, [ordered_set, private, named_table]),
+    AuthDbName = couch_config:get("couch_httpd_auth", "authentication_db"),
+    true = ets:insert(?STATE, {auth_db_name, ?l2b(AuthDbName)}),
+    true = ets:insert(?STATE, {auth_db, open_auth_db()}),
+    process_flag(trap_exit, true),
+    ok = couch_config:register(
+        fun("couch_httpd_auth", "auth_cache_size", SizeList) ->
+            Size = list_to_integer(SizeList),
+            ok = gen_server:call(?MODULE, {new_max_cache_size, Size}, infinity)
+        end
+    ),
+    ok = couch_config:register(
+        fun("couch_httpd_auth", "authentication_db", DbName) ->
+            ok = gen_server:call(?MODULE, {new_auth_db, ?l2b(DbName)}, infinity)
+        end
+    ),
+    {ok, Notifier} = couch_db_update_notifier:start_link(fun handle_db_event/1),
+    State = #state{
+        db_notifier = Notifier,
+        max_cache_size = list_to_integer(
+            couch_config:get("couch_httpd_auth", "auth_cache_size", "50")
+        )
+    },
+    {ok, State}.
+
+
+handle_db_event({Event, DbName}) ->
+    [{auth_db_name, AuthDbName}] = ets:lookup(?STATE, auth_db_name),
+    case DbName =:= AuthDbName of
+    true ->
+        case Event of
+        deleted -> gen_server:call(?MODULE, auth_db_deleted, infinity);
+        created -> gen_server:call(?MODULE, auth_db_created, infinity);
+        _Else   -> ok
+        end;
+    false ->
+        ok
+    end.
+
+
+handle_call({new_auth_db, AuthDbName}, _From, State) ->
+    NewState = clear_cache(State),
+    true = ets:insert(?STATE, {auth_db_name, AuthDbName}),
+    true = ets:insert(?STATE, {auth_db, open_auth_db()}),
+    {reply, ok, NewState};
+
+handle_call(auth_db_deleted, _From, State) ->
+    NewState = clear_cache(State),
+    true = ets:insert(?STATE, {auth_db, nil}),
+    {reply, ok, NewState};
+
+handle_call(auth_db_created, _From, State) ->
+    NewState = clear_cache(State),
+    true = ets:insert(?STATE, {auth_db, open_auth_db()}),
+    {reply, ok, NewState};
+
+handle_call({new_max_cache_size, NewSize}, _From, State) ->
+    case NewSize >= State#state.cache_size of
+    true ->
+        ok;
+    false ->
+        lists:foreach(
+            fun(_) ->
+                LruTime = ets:last(?BY_ATIME),
+                [{LruTime, UserName}] = ets:lookup(?BY_ATIME, LruTime),
+                true = ets:delete(?BY_ATIME, LruTime),
+                true = ets:delete(?BY_USER, UserName)
+            end,
+            lists:seq(1, State#state.cache_size - NewSize)
+        )
+    end,
+    NewState = State#state{
+        max_cache_size = NewSize,
+        cache_size = erlang:min(NewSize, State#state.cache_size)
+    },
+    {reply, ok, NewState};
+
+handle_call({fetch, UserName}, _From, State) ->
+    {Credentials, NewState} = case ets:lookup(?BY_USER, UserName) of
+    [{UserName, {Creds, ATime}}] ->
+        couch_stats_collector:increment({couchdb, auth_cache_hits}),
+        cache_hit(UserName, Creds, ATime),
+        {Creds, State};
+    [] ->
+        couch_stats_collector:increment({couchdb, auth_cache_misses}),
+        Creds = get_user_props_from_db(UserName),
+        State1 = add_cache_entry(UserName, Creds, erlang:now(), State),
+        {Creds, State1}
+    end,
+    {reply, Credentials, NewState};
+
+handle_call(refresh, _From, State) ->
+    exec_if_auth_db(fun refresh_entries/1),
+    {reply, ok, State}.
+
+
+handle_cast({cache_hit, UserName}, State) ->
+    case ets:lookup(?BY_USER, UserName) of
+    [{UserName, {Credentials, ATime}}] ->
+        cache_hit(UserName, Credentials, ATime);
+    _ ->
+        ok
+    end,
+    {noreply, State}.
+
+
+handle_info(_Msg, State) ->
+    {noreply, State}.
+
+
+terminate(_Reason, #state{db_notifier = Notifier}) ->
+    couch_db_update_notifier:stop(Notifier),
+    exec_if_auth_db(fun(AuthDb) -> catch couch_db:close(AuthDb) end),
+    true = ets:delete(?BY_USER),
+    true = ets:delete(?BY_ATIME),
+    true = ets:delete(?STATE).
+
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+
+
+clear_cache(State) ->
+    exec_if_auth_db(fun(AuthDb) -> catch couch_db:close(AuthDb) end),
+    true = ets:delete_all_objects(?BY_USER),
+    true = ets:delete_all_objects(?BY_ATIME),
+    State#state{cache_size = 0}.
+
+
+add_cache_entry(UserName, Credentials, ATime, State) ->
+    case State#state.cache_size >= State#state.max_cache_size of
+    true ->
+        free_mru_cache_entry();
+    false ->
+        ok
+    end,
+    true = ets:insert(?BY_ATIME, {ATime, UserName}),
+    true = ets:insert(?BY_USER, {UserName, {Credentials, ATime}}),
+    State#state{cache_size = couch_util:get_value(size, ets:info(?BY_USER))}.
+
+
+free_mru_cache_entry() ->
+    case ets:last(?BY_ATIME) of
+    '$end_of_table' ->
+        ok;  % empty cache
+    LruTime ->
+        [{LruTime, UserName}] = ets:lookup(?BY_ATIME, LruTime),
+        true = ets:delete(?BY_ATIME, LruTime),
+        true = ets:delete(?BY_USER, UserName)
+    end.
+
+
+cache_hit(UserName, Credentials, ATime) ->
+    NewATime = erlang:now(),
+    true = ets:delete(?BY_ATIME, ATime),
+    true = ets:insert(?BY_ATIME, {NewATime, UserName}),
+    true = ets:insert(?BY_USER, {UserName, {Credentials, NewATime}}).
+
+
+refresh_entries(AuthDb) ->
+    case reopen_auth_db(AuthDb) of
+    nil ->
+        ok;
+    AuthDb2 ->
+        case AuthDb2#db.update_seq > AuthDb#db.update_seq of
+        true ->
+            {ok, _, _} = couch_db:enum_docs_since(
+                AuthDb2,
+                AuthDb#db.update_seq,
+                fun(DocInfo, _, _) -> refresh_entry(AuthDb2, DocInfo) end,
+                AuthDb#db.update_seq,
+                []
+            ),
+            true = ets:insert(?STATE, {auth_db, AuthDb2});
+        false ->
+            ok
+        end
+    end.
+
+
+refresh_entry(Db, #doc_info{high_seq = DocSeq} = DocInfo) ->
+    case is_user_doc(DocInfo) of
+    {true, UserName} ->
+        case ets:lookup(?BY_USER, UserName) of
+        [] ->
+            ok;
+        [{UserName, {_OldCreds, ATime}}] ->
+            {ok, Doc} = couch_db:open_doc(Db, DocInfo, [conflicts, deleted]),
+            NewCreds = user_creds(Doc),
+            true = ets:insert(?BY_USER, {UserName, {NewCreds, ATime}})
+        end;
+    false ->
+        ok
+    end,
+    {ok, DocSeq}.
+
+
+user_creds(#doc{deleted = true}) ->
+    nil;
+user_creds(#doc{} = Doc) ->
+    {Creds} = couch_query_servers:json_doc(Doc),
+    Creds.
+
+
+is_user_doc(#doc_info{id = <<"org.couchdb.user:", UserName/binary>>}) ->
+    {true, UserName};
+is_user_doc(_) ->
+    false.
+
+
+maybe_refresh_cache() ->
+    case cache_needs_refresh() of
+    true ->
+        ok = gen_server:call(?MODULE, refresh, infinity);
+    false ->
+        ok
+    end.
+
+
+cache_needs_refresh() ->
+    exec_if_auth_db(
+        fun(AuthDb) ->
+            case reopen_auth_db(AuthDb) of
+            nil ->
+                false;
+            AuthDb2 ->
+                AuthDb2#db.update_seq > AuthDb#db.update_seq
+            end
+        end,
+        false
+    ).
+
+
+reopen_auth_db(AuthDb) ->
+    case (catch gen_server:call(AuthDb#db.main_pid, get_db, infinity)) of
+    {ok, AuthDb2} ->
+        AuthDb2;
+    _ ->
+        nil
+    end.
+
+
+exec_if_auth_db(Fun) ->
+    exec_if_auth_db(Fun, ok).
+
+exec_if_auth_db(Fun, DefRes) ->
+    case ets:lookup(?STATE, auth_db) of
+    [{auth_db, #db{} = AuthDb}] ->
+        Fun(AuthDb);
+    _ ->
+        DefRes
+    end.
+
+
+open_auth_db() ->
+    [{auth_db_name, DbName}] = ets:lookup(?STATE, auth_db_name),
+    {ok, AuthDb} = ensure_users_db_exists(DbName, [sys_db]),
+    AuthDb.
+
+
+get_user_props_from_db(UserName) ->
+    exec_if_auth_db(
+        fun(AuthDb) ->
+            Db = reopen_auth_db(AuthDb),
+            DocId = <<"org.couchdb.user:", UserName/binary>>,
+            try
+                {ok, Doc} = couch_db:open_doc(Db, DocId, [conflicts]),
+                {DocProps} = couch_query_servers:json_doc(Doc),
+                DocProps
+            catch
+            _:_Error ->
+                nil
+            end
+        end,
+        nil
+    ).
+
+ensure_users_db_exists(DbName, Options) ->
+    Options1 = [{user_ctx, #user_ctx{roles=[<<"_admin">>]}} | Options],
+    case couch_db:open(DbName, Options1) of
+    {ok, Db} ->
+        ensure_auth_ddoc_exists(Db, <<"_design/_auth">>),
+        {ok, Db};
+    _Error ->
+        {ok, Db} = couch_db:create(DbName, Options1),
+        ok = ensure_auth_ddoc_exists(Db, <<"_design/_auth">>),
+        {ok, Db}
+    end.
+
+ensure_auth_ddoc_exists(Db, DDocId) ->
+    case couch_db:open_doc(Db, DDocId) of
+    {not_found, _Reason} ->
+        {ok, AuthDesign} = auth_design_doc(DDocId),
+        {ok, _Rev} = couch_db:update_doc(Db, AuthDesign, []);
+    _ ->
+        ok
+    end,
+    ok.
+
+auth_design_doc(DocId) ->
+    DocProps = [
+        {<<"_id">>, DocId},
+        {<<"language">>,<<"javascript">>},
+        {<<"validate_doc_update">>, ?AUTH_DB_DOC_VALIDATE_FUNCTION}
+    ],
+    {ok, couch_doc:from_json_obj({DocProps})}.