%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2012. 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(snmpa_mib).
%% c(snmpa_mib).
%%%-----------------------------------------------------------------
%%% This module implements a MIB server.
%%%-----------------------------------------------------------------
%% External exports
-export([start_link/3, stop/1,
lookup/2, next/3, which_mib/2, which_mibs/1, whereis_mib/2,
load_mibs/2, unload_mibs/2,
register_subagent/3, unregister_subagent/2, info/1, info/2,
verbosity/2, dump/1, dump/2,
backup/2,
invalidate_cache/1,
gc_cache/1, gc_cache/2, gc_cache/3,
enable_cache/1, disable_cache/1,
enable_cache_autogc/1, disable_cache_autogc/1,
update_cache_gclimit/2,
update_cache_age/2,
which_cache_size/1
]).
%% Internal exports
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2,
code_change/3]).
-include_lib("kernel/include/file.hrl").
-include("snmpa_internal.hrl").
-include("snmp_types.hrl").
-include("snmp_verbosity.hrl").
-include("snmp_debug.hrl").
-define(SERVER, ?MODULE).
-define(NO_CACHE, no_mibs_cache).
-define(DEFAULT_CACHE_USAGE, true).
-define(CACHE_GC_TICKTIME, timer:minutes(1)).
-define(DEFAULT_CACHE_AUTOGC, true).
-define(DEFAULT_CACHE_GCLIMIT, 100).
-define(DEFAULT_CACHE_AGE, timer:minutes(10)).
-define(CACHE_GC_TRIGGER, cache_gc_trigger).
-ifdef(snmp_debug).
-define(GS_START_LINK(Prio, Mibs, Opts),
gen_server:start_link(?MODULE, [Prio, Mibs, Opts], [{debug,[trace]}])).
-else.
-define(GS_START_LINK(Prio, Mibs, Opts),
gen_server:start_link(?MODULE, [Prio, Mibs, Opts], [])).
-endif.
%%-----------------------------------------------------------------
%% Internal Data structures
%%
%% State
%% data - is the MIB data (defined in snmpa_mib_data)
%% meo - mib entry override
%% teo - trap (notification) entry override
%%-----------------------------------------------------------------
-record(state, {data, meo, teo, backup,
cache, cache_tmr, cache_autogc, cache_gclimit, cache_age}).
%%-----------------------------------------------------------------
%% Func: start_link/1
%% Args: Mibs is a list of mibnames.
%% Prio is priority of mib-server
%% Opts is a list of options
%% Purpose: starts the mib server synchronized
%% Returns: {ok, Pid} | {error, Reason}
%%-----------------------------------------------------------------
start_link(Prio, Mibs, Opts) ->
?d("start_link -> entry with"
"~n Prio: ~p"
"~n Mibs: ~p"
"~n Opts: ~p", [Prio, Mibs, Opts]),
?GS_START_LINK(Prio, Mibs, Opts).
verbosity(MibServer, Verbosity) ->
cast(MibServer, {verbosity,Verbosity}).
stop(MibServer) ->
call(MibServer, stop).
invalidate_cache(MibServer) ->
call(MibServer, invalidate_cache).
gc_cache(MibServer) ->
call(MibServer, gc_cache).
gc_cache(MibServer, Age) ->
call(MibServer, {gc_cache, Age}).
gc_cache(MibServer, Age, GcLimit) ->
call(MibServer, {gc_cache, Age, GcLimit}).
which_cache_size(MibServer) ->
call(MibServer, cache_size).
enable_cache(MibServer) ->
update_cache_opts(MibServer, cache, true).
disable_cache(MibServer) ->
update_cache_opts(MibServer, cache, false).
enable_cache_autogc(MibServer) ->
update_cache_opts(MibServer, autogc, true).
disable_cache_autogc(MibServer) ->
update_cache_opts(MibServer, autogc, false).
update_cache_gclimit(MibServer, GcLimit)
when ((is_integer(GcLimit) andalso (GcLimit > 0)) orelse
(GcLimit =:= infinity)) ->
update_cache_opts(MibServer, gclimit, GcLimit);
update_cache_gclimit(_, BadLimit) ->
{error, {bad_gclimit, BadLimit}}.
update_cache_age(MibServer, Age)
when is_integer(Age) andalso (Age > 0) ->
update_cache_opts(MibServer, age, Age);
update_cache_age(_, BadAge) ->
{error, {bad_age, BadAge}}.
update_cache_opts(MibServer, Key, Value) ->
call(MibServer, {update_cache_opts, Key, Value}).
%%-----------------------------------------------------------------
%% Func: lookup/2
%% Purpose: Finds the mib entry corresponding to the Oid. If it is a
%% variable, the Oid must be <Oid for var>.0 and if it is
%% a table, Oid must be <table>.<entry>.<col>.<any>
%% Returns: {variable, MibEntry} |
%% {table_column, MibEntry, TableEntryOid} |
%% {subagent, SubAgentPid} |
%% false
%%-----------------------------------------------------------------
lookup(MibServer, Oid) ->
call(MibServer, {lookup, Oid}).
which_mib(MibServer, Oid) ->
call(MibServer, {which_mib, Oid}).
%%-----------------------------------------------------------------
%% Func: next/3
%% Purpose: Finds the lexicographically next oid.
%% Returns: {subagent, SubAgentPid, SANextOid} |
%% endOfMibView |
%% genErr |
%% NextOid
%% The SANextOid is used by the agent if the SubAgent returns
%% endOfMib, in a new call to next/2.
%%-----------------------------------------------------------------
next(MibServer, Oid, MibView) ->
call(MibServer, {next, Oid, MibView}).
%%----------------------------------------------------------------------
%% Purpose: Loads mibs into the mib process.
%% Args: Mibs is a list of Filenames (compiled mibs).
%% Returns: ok | {error, Reason}
%%----------------------------------------------------------------------
load_mibs(MibServer, Mibs) ->
call(MibServer, {load_mibs, Mibs}).
%%----------------------------------------------------------------------
%% Purpose: Loads mibs into the mib process.
%% Args: Mibs is a list of Filenames (compiled mibs).
%% Returns: ok | {error, Reason}
%%----------------------------------------------------------------------
unload_mibs(MibServer, Mibs) ->
call(MibServer, {unload_mibs, Mibs}).
%%----------------------------------------------------------------------
%% Purpose: Simple management functions
%% Args: Mib is the name of the mib (atom)
%% Returns: ok | {error, Reason}
%%----------------------------------------------------------------------
which_mibs(MibServer) ->
call(MibServer, which_mibs).
whereis_mib(MibServer, Mib) ->
call(MibServer, {whereis_mib, Mib}).
%%----------------------------------------------------------------------
%% Registers subagent with pid Pid under subtree Oid.
%%----------------------------------------------------------------------
register_subagent(MibServer, Oid, Pid) ->
call(MibServer, {register_subagent, Oid, Pid}).
unregister_subagent(MibServer, OidOrPid) ->
call(MibServer, {unregister_subagent, OidOrPid}).
info(MibServer) ->
call(MibServer, info).
info(MibServer, Type) ->
call(MibServer, {info, Type}).
dump(MibServer) ->
call(MibServer, dump).
dump(MibServer, File) when is_list(File) ->
call(MibServer, {dump, File}).
backup(MibServer, BackupDir) when is_list(BackupDir) ->
call(MibServer, {backup, BackupDir}).
%%--------------------------------------------------
%% The standard MIB 'stdmib' must be present in the
%% current directory.
%%--------------------------------------------------
init([Prio, Mibs, Opts]) ->
?d("init -> entry with"
"~n Prio: ~p"
"~n Mibs: ~p"
"~n Opts: ~p", [Prio, Mibs, Opts]),
case (catch do_init(Prio, Mibs, Opts)) of
{ok, State} ->
{ok, State};
{error, Reason} ->
config_err("failed starting mib-server: ~n~p", [Reason]),
{stop, {error, Reason}};
Error ->
config_err("failed starting mib-server: ~n~p", [Error]),
{stop, {error, Error}}
end.
do_init(Prio, Mibs, Opts) ->
process_flag(priority, Prio),
process_flag(trap_exit, true),
put(sname,ms),
put(verbosity, ?vvalidate(get_verbosity(Opts))),
?vlog("starting",[]),
%% Extract the cache options
{Cache, CacheOptions} =
case get_opt(cache, Opts, ?DEFAULT_CACHE_USAGE) of
true ->
{new_cache(), []};
false ->
{?NO_CACHE, []};
CacheOpts when is_list(CacheOpts) ->
{new_cache(), CacheOpts};
Bad ->
throw({error, {bad_option, {cache, Bad}}})
end,
CacheAutoGC = get_cacheopt_autogc(Cache, CacheOptions),
CacheGcLimit = get_cacheopt_gclimit(Cache, CacheOptions),
CacheAge = get_cacheopt_age(Cache, CacheOptions),
%% Maybe start the cache gc timer
CacheGcTimer =
if
((Cache =/= ?NO_CACHE) andalso
(CacheAutoGC =:= true)) ->
start_cache_gc_timer();
true ->
undefined
end,
MeOverride = get_me_override(Opts),
TeOverride = get_te_override(Opts),
MibStorage = get_mib_storage(Opts),
Data = snmpa_mib_data:new(MibStorage),
?vtrace("init -> mib data created",[]),
case (catch mib_operations(load_mib, Mibs, Data,
MeOverride, TeOverride, true)) of
{ok, Data2} ->
?vdebug("started",[]),
snmpa_mib_data:sync(Data2),
?vdebug("mib data synced",[]),
{ok, #state{data = Data2,
teo = TeOverride,
meo = MeOverride,
cache = Cache,
cache_tmr = CacheGcTimer,
cache_autogc = CacheAutoGC,
cache_gclimit = CacheGcLimit,
cache_age = CacheAge}};
{'aborted at', Mib, _NewData, Reason} ->
?vinfo("failed loading mib ~p: ~p",[Mib,Reason]),
{error, {Mib, Reason}}
end.
%%----------------------------------------------------------------------
%% Returns: {ok, NewMibData} | {'aborted at', Mib, NewData, Reason}
%% Args: Operation is load_mib | unload_mib.
%%----------------------------------------------------------------------
mib_operations(Operation, Mibs, Data, MeOverride, TeOverride) ->
mib_operations(Operation, Mibs, Data, MeOverride, TeOverride, false).
mib_operations(_Operation, [], Data, _MeOverride, _TeOverride, _Force) ->
{ok, Data};
mib_operations(Operation, [Mib|Mibs], Data0, MeOverride, TeOverride, Force) ->
?vtrace("mib operations ~p on"
"~n Mibs: ~p"
"~n with "
"~n MeOverride: ~p"
"~n TeOverride: ~p"
"~n Force: ~p", [Operation,Mibs,MeOverride,TeOverride,Force]),
Data = mib_operation(Operation, Mib, Data0, MeOverride, TeOverride, Force),
mib_operations(Operation, Mibs, Data, MeOverride, TeOverride, Force).
mib_operation(Operation, Mib, Data0, MeOverride, TeOverride, Force)
when is_list(Mib) ->
?vtrace("mib operation on mib ~p", [Mib]),
case apply(snmpa_mib_data, Operation, [Data0,Mib,MeOverride,TeOverride]) of
{error, 'already loaded'} when (Operation =:= load_mib) andalso
(Force =:= true) ->
?vlog("ignore mib ~p -> already loaded", [Mib]),
Data0;
{error, 'not loaded'} when (Operation =:= unload_mib) andalso
(Force =:= true) ->
?vlog("ignore mib ~p -> not loaded", [Mib]),
Data0;
{error, Reason} ->
?vlog("mib_operation -> failed ~p of mib ~p for ~p",
[Operation, Mib, Reason]),
throw({'aborted at', Mib, Data0, Reason});
{ok, Data} ->
Data
end;
mib_operation(_Op, Mib, Data, _MeOverride, _TeOverride, _Force) ->
throw({'aborted at', Mib, Data, bad_mibname}).
%%-----------------------------------------------------------------
%% Handle messages
%%-----------------------------------------------------------------
handle_call(invalidate_cache, _From, #state{cache = Cache} = State) ->
?vlog("invalidate_cache", []),
NewCache = maybe_invalidate_cache(Cache),
{reply, ignore, State#state{cache = NewCache}};
handle_call(cache_size, _From, #state{cache = Cache} = State) ->
?vlog("cache_size", []),
Reply = maybe_cache_size(Cache),
{reply, Reply, State};
handle_call(gc_cache, _From,
#state{cache = Cache,
cache_age = Age,
cache_gclimit = GcLimit} = State) ->
?vlog("gc_cache", []),
Result = maybe_gc_cache(Cache, Age, GcLimit),
{reply, Result, State};
handle_call({gc_cache, Age}, _From,
#state{cache = Cache,
cache_gclimit = GcLimit} = State) ->
?vlog("gc_cache with Age = ~p", [Age]),
Result = maybe_gc_cache(Cache, Age, GcLimit),
{reply, Result, State};
handle_call({gc_cache, Age, GcLimit}, _From,
#state{cache = Cache} = State) ->
?vlog("gc_cache with Age = ~p and GcLimut = ~p", [Age, GcLimit]),
Result = maybe_gc_cache(Cache, Age, GcLimit),
{reply, Result, State};
handle_call({update_cache_opts, Key, Value}, _From, State) ->
?vlog("update_cache_opts: ~p -> ~p", [Key, Value]),
{Result, NewState} = handle_update_cache_opts(Key, Value, State),
{reply, Result, NewState};
handle_call({lookup, Oid}, _From,
#state{data = Data, cache = Cache} = State) ->
?vlog("lookup ~p", [Oid]),
Key = {lookup, Oid},
{Reply, NewState} =
case maybe_cache_lookup(Cache, Key) of
?NO_CACHE ->
{snmpa_mib_data:lookup(Data, Oid), State};
[] ->
Rep = snmpa_mib_data:lookup(Data, Oid),
ets:insert(Cache, {Key, Rep, timestamp()}),
{Rep, maybe_start_cache_gc_timer(State)};
[{Key, Rep, _}] ->
?vdebug("lookup -> found in cache", []),
ets:update_element(Cache, Key, {3, timestamp()}),
{Rep, State}
end,
?vdebug("lookup -> Reply: ~p", [Reply]),
{reply, Reply, NewState};
handle_call({which_mib, Oid}, _From, #state{data = Data} = State) ->
?vlog("which_mib ~p",[Oid]),
Reply = snmpa_mib_data:which_mib(Data, Oid),
?vdebug("which_mib: ~p",[Reply]),
{reply, Reply, State};
handle_call({next, Oid, MibView}, _From,
#state{data = Data, cache = Cache} = State) ->
?vlog("next ~p [~p]", [Oid, MibView]),
Key = {next, Oid, MibView},
{Reply, NewState} =
case maybe_cache_lookup(Cache, Key) of
?NO_CACHE ->
{snmpa_mib_data:next(Data, Oid, MibView), State};
[] ->
Rep = snmpa_mib_data:next(Data, Oid, MibView),
ets:insert(Cache, {Key, Rep, timestamp()}),
{Rep, maybe_start_cache_gc_timer(State)};
[{Key, Rep, _}] ->
?vdebug("lookup -> found in cache", []),
ets:update_element(Cache, Key, {3, timestamp()}),
{Rep, State}
end,
?vdebug("next -> Reply: ~p", [Reply]),
{reply, Reply, NewState};
handle_call({load_mibs, Mibs}, _From,
#state{data = Data,
teo = TeOverride,
meo = MeOverride,
cache = Cache} = State) ->
?vlog("load mibs ~p",[Mibs]),
%% Invalidate cache
NewCache = maybe_invalidate_cache(Cache),
{NData,Reply} =
case (catch mib_operations(load_mib, Mibs, Data,
MeOverride, TeOverride)) of
{'aborted at', Mib, NewData, Reason} ->
?vlog("aborted at ~p for reason ~p",[Mib,Reason]),
{NewData,{error, {'load aborted at', Mib, Reason}}};
{ok, NewData} ->
{NewData,ok}
end,
snmpa_mib_data:sync(NData),
{reply, Reply, State#state{data = NData, cache = NewCache}};
handle_call({unload_mibs, Mibs}, _From,
#state{data = Data,
teo = TeOverride,
meo = MeOverride,
cache = Cache} = State) ->
?vlog("unload mibs ~p",[Mibs]),
%% Invalidate cache
NewCache = maybe_invalidate_cache(Cache),
%% Unload mib(s)
{NData,Reply} =
case (catch mib_operations(unload_mib, Mibs, Data,
MeOverride, TeOverride)) of
{'aborted at', Mib, NewData, Reason} ->
?vlog("aborted at ~p for reason ~p",[Mib,Reason]),
{NewData, {error, {'unload aborted at', Mib, Reason}}};
{ok, NewData} ->
{NewData,ok}
end,
snmpa_mib_data:sync(NData),
{reply, Reply, State#state{data = NData, cache = NewCache}};
handle_call(which_mibs, _From, #state{data = Data} = State) ->
?vlog("which mibs",[]),
Reply = snmpa_mib_data:which_mibs(Data),
{reply, Reply, State};
handle_call({whereis_mib, Mib}, _From, #state{data = Data} = State) ->
?vlog("whereis mib: ~p",[Mib]),
Reply = snmpa_mib_data:whereis_mib(Data, Mib),
{reply, Reply, State};
handle_call({register_subagent, Oid, Pid}, _From,
#state{data = Data, cache = Cache} = State) ->
?vlog("register subagent ~p, ~p",[Oid,Pid]),
%% Invalidate cache
NewCache = maybe_invalidate_cache(Cache),
case snmpa_mib_data:register_subagent(Data, Oid, Pid) of
{error, Reason} ->
?vlog("registration failed: ~p",[Reason]),
{reply, {error, Reason}, State#state{cache = NewCache}};
NewData ->
{reply, ok, State#state{data = NewData, cache = NewCache}}
end;
handle_call({unregister_subagent, OidOrPid}, _From,
#state{data = Data, cache = Cache} = State) ->
?vlog("unregister subagent ~p",[OidOrPid]),
%% Invalidate cache
NewCache = maybe_invalidate_cache(Cache),
case snmpa_mib_data:unregister_subagent(Data, OidOrPid) of
{ok, NewData, DeletedSubagentPid} ->
{reply, {ok, DeletedSubagentPid}, State#state{data = NewData,
cache = NewCache}};
{error, Reason} ->
?vlog("unregistration failed: ~p",[Reason]),
{reply, {error, Reason}, State#state{cache = NewCache}};
NewData ->
{reply, ok, State#state{data = NewData, cache = NewCache}}
end;
handle_call(info, _From, #state{data = Data, cache = Cache} = State) ->
?vlog("info",[]),
Reply =
case (catch snmpa_mib_data:info(Data)) of
Info when is_list(Info) ->
[{cache, size_cache(Cache)} | Info];
E ->
[{error, E}]
end,
{reply, Reply, State};
handle_call({info, Type}, _From, #state{data = Data} = State) ->
?vlog("info ~p",[Type]),
Reply =
case (catch snmpa_mib_data:info(Data, Type)) of
Info when is_list(Info) ->
Info;
E ->
[{error, E}]
end,
{reply, Reply, State};
handle_call(dump, _From, State) ->
?vlog("dump",[]),
Reply = snmpa_mib_data:dump(State#state.data),
{reply, Reply, State};
handle_call({dump, File}, _From, #state{data = Data} = State) ->
?vlog("dump on ~s",[File]),
Reply = snmpa_mib_data:dump(Data, File),
{reply, Reply, State};
%% This check (that there is no backup already in progress) is also
%% done in the master agent process, but just in case a user issues
%% a backup call to this process directly, we add a similar check here.
handle_call({backup, BackupDir}, From,
#state{backup = undefined, data = Data} = State) ->
?vlog("backup to ~s", [BackupDir]),
Pid = self(),
V = get(verbosity),
case file:read_file_info(BackupDir) of
{ok, #file_info{type = directory}} ->
BackupServer =
erlang:spawn_link(
fun() ->
put(sname, ambs),
put(verbosity, V),
Dir = filename:join([BackupDir]),
Reply = snmpa_mib_data:backup(Data, Dir),
Pid ! {backup_done, Reply},
unlink(Pid)
end),
?vtrace("backup server: ~p", [BackupServer]),
{noreply, State#state{backup = {BackupServer, From}}};
{ok, _} ->
{reply, {error, not_a_directory}, State};
Error ->
{reply, Error, State}
end;
handle_call({backup, _BackupDir}, From, #state{backup = Backup} = S) ->
?vinfo("backup already in progress: ~p", [Backup]),
{reply, {error, backup_in_progress}, S};
handle_call(stop, _From, State) ->
?vlog("stop",[]),
{stop, normal, ok, State};
handle_call(Req, _From, State) ->
warning_msg("received unknown request: ~n~p", [Req]),
Reply = {error, {unknown, Req}},
{reply, Reply, State}.
handle_cast({verbosity, Verbosity}, State) ->
?vlog("verbosity: ~p -> ~p",[get(verbosity),Verbosity]),
put(verbosity,snmp_verbosity:validate(Verbosity)),
{noreply, State};
handle_cast(Msg, State) ->
warning_msg("received unknown message: ~n~p", [Msg]),
{noreply, State}.
handle_info({'EXIT', Pid, Reason}, #state{backup = {Pid, From}} = S) ->
?vlog("backup server (~p) exited for reason ~n~p", [Pid, Reason]),
gen_server:reply(From, {error, Reason}),
{noreply, S#state{backup = undefined}};
handle_info({'EXIT', Pid, Reason}, S) ->
%% The only other processes we should be linked to are
%% either the master agent or our supervisor, so die...
{stop, {received_exit, Pid, Reason}, S};
handle_info({backup_done, Reply}, #state{backup = {_, From}} = S) ->
?vlog("backup done:"
"~n Reply: ~p", [Reply]),
gen_server:reply(From, Reply),
{noreply, S#state{backup = undefined}};
handle_info(?CACHE_GC_TRIGGER, #state{cache = Cache,
cache_age = Age,
cache_gclimit = GcLimit,
cache_autogc = true} = S)
when (Cache =/= ?NO_CACHE) ->
?vlog("cache gc trigger event", []),
maybe_gc_cache(Cache, Age, GcLimit),
Tmr = start_cache_gc_timer(),
{noreply, S#state{cache_tmr = Tmr}};
handle_info(?CACHE_GC_TRIGGER, S) ->
?vlog("out-of-date cache gc trigger event - ignore", []),
{noreply, S#state{cache_tmr = undefined}};
handle_info(Info, State) ->
warning_msg("received unknown info: ~n~p", [Info]),
{noreply, State}.
terminate(_Reason, #state{data = Data}) ->
catch snmpa_mib_data:close(Data),
ok.
%%----------------------------------------------------------
%% Code change
%%----------------------------------------------------------
%% downgrade
%%
%% code_change({down, _Vsn}, S1, downgrade_to_pre_4_12) ->
%% #state{data = Data, meo = MEO, teo = TEO, backup = B, cache = Cache} = S1,
%% del_cache(Cache),
%% S2 = {state, Data, MEO, TEO, B},
%% {ok, S2};
%% %% upgrade
%% %%
%% code_change(_Vsn, S1, upgrade_from_pre_4_12) ->
%% {state, Data, MEO, TEO, B} = S1,
%% Cache = new_cache(),
%% S2 = #state{data = Data, meo = MEO, teo = TEO, backup = B, cache = Cache},
%% {ok, S2};
code_change(_Vsn, State, _Extra) ->
{ok, State}.
%%-----------------------------------------------------------------
%% Option access functions
%%-----------------------------------------------------------------
get_verbosity(Options) ->
get_opt(verbosity, Options, ?default_verbosity).
get_me_override(Options) ->
get_opt(mibentry_override, Options, false).
get_te_override(Options) ->
get_opt(trapentry_override, Options, false).
get_mib_storage(Options) ->
get_opt(mib_storage, Options, ets).
get_cacheopt_autogc(Cache, CacheOpts) ->
IsValid = fun(AutoGC) when ((AutoGC =:= true) orelse
(AutoGC =:= false)) ->
true;
(_) ->
false
end,
get_cacheopt(Cache, autogc, CacheOpts,
false, ?DEFAULT_CACHE_AUTOGC,
IsValid).
get_cacheopt_gclimit(Cache, CacheOpts) ->
IsValid = fun(Limit) when ((is_integer(Limit) andalso (Limit > 0)) orelse
(Limit =:= infinity)) ->
true;
(_) ->
false
end,
get_cacheopt(Cache, gclimit, CacheOpts,
infinity, ?DEFAULT_CACHE_GCLIMIT,
IsValid).
get_cacheopt_age(Cache, CacheOpts) ->
IsValid = fun(Age) when is_integer(Age) andalso (Age > 0) ->
true;
(_) ->
false
end,
get_cacheopt(Cache, age, CacheOpts,
?DEFAULT_CACHE_AGE, ?DEFAULT_CACHE_AGE,
IsValid).
get_cacheopt(?NO_CACHE, _, _, NoCacheVal, _, _) ->
NoCacheVal;
get_cacheopt(_, Key, Opts, _, Default, IsValid) ->
Val = get_opt(Key, Opts, Default),
case IsValid(Val) of
true ->
Val;
false ->
throw({error, {bad_option, {Key, Val}}})
end.
%% ----------------------------------------------------------------
handle_update_cache_opts(cache, true = _Value,
#state{cache = ?NO_CACHE} = State) ->
{ok, State#state{cache = new_cache()}};
handle_update_cache_opts(cache, true = _Value, State) ->
{ok, State};
handle_update_cache_opts(cache, false = _Value,
#state{cache = ?NO_CACHE} = State) ->
{ok, State};
handle_update_cache_opts(cache, false = _Value,
#state{cache = Cache,
cache_tmr = Tmr} = State) ->
maybe_stop_cache_gc_timer(Tmr),
del_cache(Cache),
{ok, State#state{cache = ?NO_CACHE, cache_tmr = undefined}};
handle_update_cache_opts(autogc, true = _Value,
#state{cache_autogc = true} = State) ->
{ok, State};
handle_update_cache_opts(autogc, true = Value, State) ->
{ok, maybe_start_cache_gc_timer(State#state{cache_autogc = Value})};
handle_update_cache_opts(autogc, false = _Value,
#state{cache_autogc = false} = State) ->
{ok, State};
handle_update_cache_opts(autogc, false = Value,
#state{cache_tmr = Tmr} = State) ->
maybe_stop_cache_gc_timer(Tmr),
{ok, State#state{cache_autogc = Value, cache_tmr = undefined}};
handle_update_cache_opts(age, Age, State) ->
{ok, State#state{cache_age = Age}};
handle_update_cache_opts(gclimit, GcLimit, State) ->
{ok, State#state{cache_gclimit = GcLimit}};
handle_update_cache_opts(BadKey, Value, State) ->
{{error, {bad_cache_opt, BadKey, Value}}, State}.
maybe_stop_cache_gc_timer(undefined) ->
ok;
maybe_stop_cache_gc_timer(Tmr) ->
erlang:cancel_timer(Tmr).
maybe_start_cache_gc_timer(#state{cache = Cache,
cache_autogc = true,
cache_tmr = undefined} = State)
when (Cache =/= ?NO_CACHE) ->
Tmr = start_cache_gc_timer(),
State#state{cache_tmr = Tmr};
maybe_start_cache_gc_timer(State) ->
State.
start_cache_gc_timer() ->
erlang:send_after(?CACHE_GC_TICKTIME, self(), ?CACHE_GC_TRIGGER).
%% ----------------------------------------------------------------
maybe_gc_cache(?NO_CACHE, _Age) ->
?vtrace("cache not enabled", []),
ok;
maybe_gc_cache(Cache, Age) ->
MatchSpec = gc_cache_matchspec(Age),
Keys = ets:select(Cache, MatchSpec),
do_gc_cache(Cache, Keys),
{ok, length(Keys)}.
maybe_gc_cache(?NO_CACHE, _Age, _GcLimit) ->
ok;
maybe_gc_cache(Cache, Age, infinity = _GcLimit) ->
maybe_gc_cache(Cache, Age);
maybe_gc_cache(Cache, Age, GcLimit) ->
MatchSpec = gc_cache_matchspec(Age),
Keys =
case ets:select(Cache, MatchSpec, GcLimit) of
{Match, _Cont} ->
Match;
'$end_of_table' ->
[]
end,
do_gc_cache(Cache, Keys),
{ok, length(Keys)}.
gc_cache_matchspec(Age) ->
Oldest = timestamp() - Age,
MatchHead = {'$1', '_', '$2'},
Guard = [{'<', '$2', Oldest}],
MatchFunc = {MatchHead, Guard, ['$1']},
MatchSpec = [MatchFunc],
MatchSpec.
do_gc_cache(_, []) ->
ok;
do_gc_cache(Cache, [Key|Keys]) ->
ets:delete(Cache, Key),
do_gc_cache(Cache, Keys).
maybe_invalidate_cache(?NO_CACHE) ->
?NO_CACHE;
maybe_invalidate_cache(Cache) ->
del_cache(Cache),
new_cache().
maybe_cache_size(?NO_CACHE) ->
{error, not_enabled};
maybe_cache_size(Cache) ->
{ok, ets:info(Cache, size)}.
new_cache() ->
ets:new(snmpa_mib_cache, [set, protected, {keypos, 1}]).
del_cache(?NO_CACHE) ->
ok;
del_cache(Cache) ->
ets:delete(Cache).
maybe_cache_lookup(?NO_CACHE, _) ->
?NO_CACHE;
maybe_cache_lookup(Cache, Key) ->
ets:lookup(Cache, Key).
size_cache(?NO_CACHE) ->
undefined;
size_cache(Cache) ->
case (catch ets:info(Cache, memory)) of
Sz when is_integer(Sz) ->
Sz;
_ ->
undefined
end.
timestamp() ->
snmp_misc:now(ms).
%% ----------------------------------------------------------------
get_opt(Key, Options, Default) ->
snmp_misc:get_option(Key, Options, Default).
%% ----------------------------------------------------------------
cast(MibServer, Msg) ->
gen_server:cast(MibServer, Msg).
call(MibServer, Req) ->
call(MibServer, Req, infinity).
call(MibServer, Req, To) ->
gen_server:call(MibServer, Req, To).
%% ----------------------------------------------------------------
%% info_msg(F, A) ->
%% ?snmpa_info("Mib server: " ++ F, A).
warning_msg(F, A) ->
?snmpa_warning("Mib server: " ++ F, A).
%% error_msg(F, A) ->
%% ?snmpa_error("Mib server: " ++ F, A).
config_err(F, A) ->
snmpa_error:config_err(F, A).
