diff options
Diffstat (limited to 'lib/snmp/src/agent/snmpa_mib_storage_ets.erl')
-rw-r--r-- | lib/snmp/src/agent/snmpa_mib_storage_ets.erl | 341 |
1 files changed, 341 insertions, 0 deletions
diff --git a/lib/snmp/src/agent/snmpa_mib_storage_ets.erl b/lib/snmp/src/agent/snmpa_mib_storage_ets.erl new file mode 100644 index 0000000000..04faf46864 --- /dev/null +++ b/lib/snmp/src/agent/snmpa_mib_storage_ets.erl @@ -0,0 +1,341 @@ +%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 2013-2013. 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_storage_ets). + +-behaviour(snmpa_mib_storage). + +%%%----------------------------------------------------------------- +%%% This module implements the snmpa_mib_storage behaviour. +%%% It uses ets for storage. +%%%----------------------------------------------------------------- + +-export([ + open/5, + close/1, + read/2, + write/2, + delete/1, + delete/2, + match_object/2, + match_delete/2, + tab2list/1, + info/1, info/2, + sync/1, + backup/2 + ]). + + +-define(VMODULE,"MS-ETS"). +-include("snmp_verbosity.hrl"). + +-record(tab, {id, rec_name, file, checksum = false}). + + +%% --------------------------------------------------------------- +%% open +%% +%% Open or create an ets table. +%% Possibly also read data from a (specified) file (mirror) and +%% populate the table from that (the dir option). +%% +%% Opts - A list of implementation dependent options +%% ets_open_options() = [ets_open_option()] +%% ets_open_option() = {dir, filename()} | +%% {action, keep | clear} | +%% {checksum, boolean()} +%% +%% The RecName and Fields arguments are not used in this +%% implementation. +%% +%% --------------------------------------------------------------- + +%% This function creates the ets table +open(Name, RecName, _Fields, Type, Opts) -> + ?vtrace("open table ~p", [Name]), + case lists:keysearch(dir, 1, Opts) of + {value, {dir, Dir}} -> + Action = snmp_misc:get_option(action, Opts, keep), + Checksum = snmp_misc:get_option(checksum, Opts, false), + ?vtrace("open ~p database ~p - check if file exist", [Type, Name]), + File = filename:join(Dir, atom_to_list(Name) ++ ".db"), + case file:read_file_info(File) of + {ok, _} -> + ?vdebug("open ~p database ~p - file exist - try reading", + [Type, Name]), + case ets:file2tab(File, [{verify, Checksum}]) of + {ok, ID} -> + ?vtrace("open ~p database ~p - " + "data read from file", [Type, Name]), + {ok, #tab{id = ID, + rec_name = RecName, + file = File, + checksum = Checksum}}; + {error, Reason} when (Action =:= keep) -> + ?vinfo("open ~p database ~p - " + "failed reading from file (keep): " + "~n ~p", + [Type, Name, Reason]), + {error, {file2tab, Reason}}; + {error, Reason} -> + ?vlog("open ~p database ~p - " + "failed reading from file (clear): " + "~n ~p", [Type, Name, Reason]), + user_err("Warning: could not read file - " + "create new (empty): " + "~n File: ~p" + "~n Reason: ~p", [File, Reason]), + ID = ets:new(Name, [Type, protected, {keypos, 2}]), + write_ets_file(ID, File, Checksum), + {ok, #tab{id = ID, + rec_name = RecName, + file = File, + checksum = Checksum}} + end; + {error, enoent} -> + %% No such file - create it + ?vdebug("open ~p database ~p - " + "file does *not* exist - create", + [Type, Name]), + ID = ets:new(Name, [Type, protected, {keypos, 2}]), + write_ets_file(ID, File, Checksum), + {ok, #tab{id = ID, + rec_name = RecName, + file = File, + checksum = Checksum}}; + {error, Reason} when (Action =:= keep) -> + ?vinfo("open ~p database ~p - " + "failed reading file info (keep): " + "~n ~p", + [Type, Name, Reason]), + {error, {read_file_info, Reason}}; + {error, Reason} -> + ?vlog("open ~p database ~p - " + "failed reading file info (clear): " + "~n ~p", + [Type, Name, Reason]), + user_err("Warning: could not read file info - " + "create new file: " + "~n File: ~p" + "~n Reason: ~p", [File, Reason]), + ID = ets:new(Name, [Type, protected, {keypos, 2}]), + write_ets_file(ID, File, Checksum), + {ok, #tab{id = ID, + rec_name = RecName, + file = File, + checksum = Checksum}} + end; + false -> + ?vdebug("open ~p database ~p - ok", [Type, Name]), + ID = ets:new(Name, [Type, protected, {keypos, 2}]), + {ok, #tab{id = ID, rec_name = RecName}} + end. + + +%% --------------------------------------------------------------- +%% close +%% +%% Close the mib-storage table. +%% We will delete the table and if there is a file component, +%% will also be written to file. +%% --------------------------------------------------------------- +close(#tab{id = ID, file = undefined}) -> + ?vtrace("close (delete) table ~p", [ID]), + ets:delete(ID); +close(#tab{id = ID, file = File, checksum = Checksum}) -> + ?vtrace("close (delete) table ~p", [ID]), + write_ets_file(ID, File, Checksum), + ets:delete(ID). + + +%% --------------------------------------------------------------- +%% read +%% +%% Retrieve a record from the mib-storage table. +%% --------------------------------------------------------------- + +read(#tab{id = ID}, Key) -> + ?vtrace("read from table ~p: ~p", [ID, Key]), + case ets:lookup(ID, Key) of + [Rec|_] -> {value, Rec}; + _ -> false + end. + + +%% --------------------------------------------------------------- +%% write +%% +%% Write a record to the mib-storage table. +%% --------------------------------------------------------------- + +%% This is a very crude guard test is used instead of: is_record(Rec, RecName) +write(#tab{id = ID, rec_name = RecName}, Rec) + when (is_tuple(Rec) andalso (element(1, Rec) =:= RecName)) -> + ?vtrace("write to table ~p", [ID]), + ets:insert(ID, Rec). + + +%% --------------------------------------------------------------- +%% delete +%% +%% Delete the mib-storage table. +%% --------------------------------------------------------------- +delete(#tab{id = ID, file = undefined}) -> + ?vtrace("delete table ~p", [ID]), + ets:delete(ID); +delete(#tab{id = ID, file = File}) -> + ?vtrace("delete table ~p", [ID]), + file:delete(File), + ets:delete(ID). + + +%% --------------------------------------------------------------- +%% delete +%% +%% Delete a record from the mib-storage table. +%% --------------------------------------------------------------- +delete(#tab{id = ID}, Key) -> + ?vtrace("delete from table ~p: ~p", [ID, Key]), + ets:delete(ID, Key). + + +%% --------------------------------------------------------------- +%% match_object +%% +%% Search the mib-storage table for records witch matches +%% the pattern. +%% --------------------------------------------------------------- + +match_object(#tab{id = ID}, Pattern) -> + ?vtrace("match_object in ~p of ~p", [ID, Pattern]), + ets:match_object(ID, Pattern). + + +%% --------------------------------------------------------------- +%% match_delete +%% +%% Search the mib-storage table for records witch matches +%% the pattern and deletes them from the table. +%% --------------------------------------------------------------- + +match_delete(#tab{id = ID}, Pattern) -> + ?vtrace("match_delete in ~p with pattern ~p", [ID, Pattern]), + Recs = ets:match_object(ID, Pattern), + ets:match_delete(ID, Pattern), + Recs. + + +%% --------------------------------------------------------------- +%% tab2list +%% +%% Return all records in the mib-storage table in the form +%% of a list. +%% --------------------------------------------------------------- + +tab2list(#tab{id = ID}) -> + ?vtrace("tab2list -> list of ~p", [ID]), + ets:tab2list(ID). + + + +%% --------------------------------------------------------------- +%% info/1,2 +%% +%% Retrieve implementation dependent mib-storage table +%% information. +%% --------------------------------------------------------------- +info(#tab{id = ID}) -> + ?vtrace("info on ~p", [ID]), + case ets:info(ID) of + undefined -> + []; + L -> + L + end. + + +info(TabId, all = _Item) -> + info(TabId); +info(#tab{id = ID}, Item) -> + ?vtrace("info on ~p", [ID]), + ets:info(ID, Item). + + +%% --------------------------------------------------------------- +%% sync +%% +%% Dump mib-storage table to disc (if there is a file compionent) +%% --------------------------------------------------------------- + +sync(#tab{file = undefined}) -> + ok; +sync(#tab{id = ID, file = File, checksum = Checksum}) -> + ?vtrace("sync ~p", [ID]), + write_ets_file(ID, File, Checksum). + + +%% --------------------------------------------------------------- +%% backup +%% +%% Make a backup copy of the mib-storage table. Only valid id +%% there is a file component. +%% --------------------------------------------------------------- + +backup(#tab{file = undefined}, _BackupDir) -> + ok; +backup(#tab{id = ID, file = File, checksum = Checksum}, BackupDir) -> + ?vtrace("backup ~p to ~p", [ID, BackupDir]), + Filename = filename:basename(File), + case filename:join(BackupDir, Filename) of + File -> + %% Oups: backup-dir and db-dir the same + {error, db_dir}; + BackupFile -> + write_ets_file(ID, BackupFile, Checksum) + end. + + +%%---------------------------------------------------------------------- + +write_ets_file(ID, File, Checksum) when (Checksum =:= true) -> + do_write_ets_file(ID, File, [{extended_info, [md5sum]}]); +write_ets_file(ID, File, Checksum) when (Checksum =:= false) -> + do_write_ets_file(ID, File, []). + +do_write_ets_file(ID, File, Options) -> + TmpFile = File ++ ".tmp", + case ets:tab2file(ID, TmpFile, Options) of + ok -> + case file:rename(TmpFile, File) of + ok -> + ok; + Else -> + user_err("Warning: could not move file ~p" + " (~p)", [File, Else]) + end; + {error, Reason} -> + user_err("Warning: could not save file ~p (~p)", + [File, Reason]) + end. + + +%%---------------------------------------------------------------------- + +user_err(F, A) -> + snmpa_error:user_err(F, A). |