%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2000-2016. All Rights Reserved.
%%
%% 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.
%%
%% %CopyrightEnd%
%%
%%%----------------------------------------------------------------------
%%% File : file_server.erl
%%% Author : Raimo Niskanen <[email protected]>
%%% Purpose : A simple file server
%%% Created : 13 Oct 2000 by Raimo Niskanen <[email protected]>
%%%----------------------------------------------------------------------
-module(file_server).
-behaviour(gen_server).
%% External exports
-export([format_error/1]).
-export([start/0, start_link/0, stop/0]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-define(FILE_IO_SERVER_TABLE, file_io_servers).
-define(FILE_SERVER, file_server_2). % Registered name
-define(FILE_IO_SERVER, file_io_server). % Module
-define(PRIM_FILE, prim_file). % Module
%%%----------------------------------------------------------------------
%%% API
%%%----------------------------------------------------------------------
format_error({_Line, ?MODULE, Reason}) ->
io_lib:format("~w", [Reason]);
format_error({_Line, Mod, Reason}) ->
Mod:format_error(Reason);
format_error(ErrorId) ->
erl_posix_msg:message(ErrorId).
start() -> do_start(start).
start_link() -> do_start(start_link).
stop() ->
gen_server:call(?FILE_SERVER, stop, infinity).
%%%----------------------------------------------------------------------
%%% Callback functions from gen_server
%%%----------------------------------------------------------------------
-type state() :: port(). % Internal type
%%----------------------------------------------------------------------
%% Func: init/1
%% Returns: {ok, State} |
%% {ok, State, Timeout} |
%% ignore |
%% {stop, Reason}
%%----------------------------------------------------------------------
-spec init([]) -> {'ok', state()} | {'stop', term()}.
init([]) ->
process_flag(trap_exit, true),
case ?PRIM_FILE:start() of
{ok, Handle} ->
?FILE_IO_SERVER_TABLE =
ets:new(?FILE_IO_SERVER_TABLE, [named_table]),
{ok, Handle};
{error, Reason} ->
{stop, Reason}
end.
%%----------------------------------------------------------------------
%% Func: handle_call/3
%% Returns: {reply, Reply, State} |
%% {reply, Reply, State, Timeout} |
%% {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, Reply, State} | (terminate/2 is called)
%% {stop, Reason, State} (terminate/2 is called)
%%----------------------------------------------------------------------
-spec handle_call(term(), term(), state()) ->
{'noreply', state()} |
{'reply', 'eof' | 'ok' | {'error', term()} | {'ok', term()}, state()} |
{'stop', 'normal', 'stopped', state()}.
handle_call({open, Name, ModeList}, {Pid, _Tag} = _From, Handle)
when is_list(ModeList) ->
Child = ?FILE_IO_SERVER:start_link(Pid, Name, ModeList),
case Child of
{ok, P} when is_pid(P) ->
ets:insert(?FILE_IO_SERVER_TABLE, {P, Name});
_ ->
ok
end,
{reply, Child, Handle};
handle_call({open, _Name, _Mode}, _From, Handle) ->
{reply, {error, einval}, Handle};
handle_call({read_file, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:read_file(Name), Handle};
handle_call({write_file, Name, Bin}, _From, Handle) ->
{reply, ?PRIM_FILE:write_file(Name, Bin), Handle};
handle_call({set_cwd, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:set_cwd(Handle, Name), Handle};
handle_call({delete, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:delete(Handle, Name), Handle};
handle_call({rename, Fr, To}, _From, Handle) ->
{reply, ?PRIM_FILE:rename(Handle, Fr, To), Handle};
handle_call({make_dir, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:make_dir(Handle, Name), Handle};
handle_call({del_dir, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:del_dir(Handle, Name), Handle};
handle_call({list_dir, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:list_dir(Handle, Name), Handle};
handle_call({list_dir_all, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:list_dir_all(Handle, Name), Handle};
handle_call(get_cwd, _From, Handle) ->
{reply, ?PRIM_FILE:get_cwd(Handle), Handle};
handle_call({get_cwd}, _From, Handle) ->
{reply, ?PRIM_FILE:get_cwd(Handle), Handle};
handle_call({get_cwd, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:get_cwd(Handle, Name), Handle};
handle_call({read_file_info, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:read_file_info(Handle, Name), Handle};
handle_call({read_file_info, Name, Opts}, _From, Handle) ->
{reply, ?PRIM_FILE:read_file_info(Handle, Name, Opts), Handle};
handle_call({altname, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:altname(Handle, Name), Handle};
handle_call({write_file_info, Name, Info}, _From, Handle) ->
{reply, ?PRIM_FILE:write_file_info(Handle, Name, Info), Handle};
handle_call({write_file_info, Name, Info, Opts}, _From, Handle) ->
{reply, ?PRIM_FILE:write_file_info(Handle, Name, Info, Opts), Handle};
handle_call({read_link_info, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:read_link_info(Handle, Name), Handle};
handle_call({read_link_info, Name, Opts}, _From, Handle) ->
{reply, ?PRIM_FILE:read_link_info(Handle, Name, Opts), Handle};
handle_call({read_link, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:read_link(Handle, Name), Handle};
handle_call({read_link_all, Name}, _From, Handle) ->
{reply, ?PRIM_FILE:read_link_all(Handle, Name), Handle};
handle_call({make_link, Old, New}, _From, Handle) ->
{reply, ?PRIM_FILE:make_link(Handle, Old, New), Handle};
handle_call({make_symlink, Old, New}, _From, Handle) ->
{reply, ?PRIM_FILE:make_symlink(Handle, Old, New), Handle};
handle_call({copy, SourceName, SourceOpts, DestName, DestOpts, Length},
_From, Handle) ->
Reply =
case ?PRIM_FILE:open(SourceName, [read, binary | SourceOpts]) of
{ok, Source} ->
SourceReply =
case ?PRIM_FILE:open(DestName,
[write, binary | DestOpts]) of
{ok, Dest} ->
DestReply =
?PRIM_FILE:copy(Source, Dest, Length),
?PRIM_FILE:close(Dest),
DestReply;
{error, _} = Error ->
Error
end,
?PRIM_FILE:close(Source),
SourceReply;
{error, _} = Error ->
Error
end,
{reply, Reply, Handle};
handle_call(stop, _From, Handle) ->
{stop, normal, stopped, Handle};
handle_call(Request, From, Handle) ->
error_logger:error_msg("handle_call(~p, ~p, _)", [Request, From]),
{noreply, Handle}.
%%----------------------------------------------------------------------
%% Func: handle_cast/2
%% Returns: {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State} (terminate/2 is called)
%%----------------------------------------------------------------------
-spec handle_cast(term(), state()) -> {'noreply', state()}.
handle_cast(Msg, State) ->
error_logger:error_msg("handle_cast(~p, _)", [Msg]),
{noreply, State}.
%%----------------------------------------------------------------------
%% Func: handle_info/2
%% Returns: {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State} (terminate/2 is called)
%%----------------------------------------------------------------------
-spec handle_info(term(), state()) ->
{'noreply', state()} | {'stop', 'normal', state()}.
handle_info({'EXIT', Pid, _Reason}, Handle) when is_pid(Pid) ->
ets:delete(?FILE_IO_SERVER_TABLE, Pid),
{noreply, Handle};
handle_info({'EXIT', Handle, _Reason}, Handle) ->
error_logger:error_msg("Port controlling ~w terminated in ~w",
[?FILE_SERVER, ?MODULE]),
{stop, normal, Handle};
handle_info(Info, State) ->
error_logger:error_msg("handle_Info(~p, _)", [Info]),
{noreply, State}.
%%----------------------------------------------------------------------
%% Func: terminate/2
%% Purpose: Shutdown the server
%% Returns: any (ignored by gen_server)
%%----------------------------------------------------------------------
-spec terminate(term(), state()) -> 'ok'.
terminate(_Reason, Handle) ->
?PRIM_FILE:stop(Handle).
%%----------------------------------------------------------------------
%% Func: code_change/3
%% Purpose: Convert process state when code is changed
%% Returns: {ok, NewState}
%%----------------------------------------------------------------------
-spec code_change(term(), state(), term()) -> {'ok', state()}.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%%%----------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------
%%% The basic file server and start-up.
%%%
%%% The file server just handles the open command/message and acts as a
%%% router for messages between the port and the file processes. If a
%%% file process terminates we close the associated file.
%% Start = start | start_link
do_start(Start) ->
case init:get_argument(master) of
error ->
gen_server:Start({local,?FILE_SERVER}, ?MODULE, [], []);
{ok, [[Node]]} ->
do_start(Start, list_to_atom(Node), ?FILE_SERVER);
X ->
{error, {get_argument, master, X}}
end.
%% Should mimic gen_server:Start
do_start(Start, Node, Name) ->
case rpc:call(Node, erlang, whereis, [Name]) of
Filer when is_pid(Filer); Filer =:= undefined ->
case catch do_start_slave(Start, Filer, Name) of
{'EXIT', Reason} ->
{error, Reason};
Result ->
Result
end;
Other ->
{error, {no_master, Other}}
end.
%% May exit upon failure, return {ok, SlavePid} if all well.
do_start_slave(start_link, Filer, Name) ->
Self = self(),
Token = make_ref(),
Slave = spawn_link(fun() -> relay_start(Self, Token, Filer, Name) end),
receive
{started, Token} ->
{ok, Slave}
end;
do_start_slave(start, Filer, Name) ->
Self = self(),
Token = make_ref(),
Slave = spawn(fun() -> relay_start(Self, Token, Filer, Name) end),
SlaveMonitor = erlang:monitor(process, Slave),
receive
{started, Token} ->
erlang:demonitor(SlaveMonitor, [flush]),
{ok, Slave};
{'DOWN', SlaveMonitor, _, _, Reason} ->
exit(Reason)
end.
%% We have the relay process file internal.
%% We do not need to load slave as a mandatory module
%% during system startup.
relay_start(Parent, Token, Filer, Name) when is_pid(Filer) ->
case catch register(Name, self()) of
true ->
ok;
_ ->
exit({already_started, whereis(Name)})
end,
%% This will fail towards an R5 node or older, Filer is a pid()
FilerMonitor = erlang:monitor(process, Filer),
process_flag(trap_exit, true),
Parent ! {started, Token},
relay_loop(Parent, Filer, FilerMonitor);
relay_start(Parent, Token, undefined, _Name) ->
%% Dummy process to keep kernel supervisor happy
process_flag(trap_exit, true),
Parent ! {started, Token},
receive
{'EXIT', Parent, Reason} ->
exit(Reason)
end.
relay_loop(Parent, Filer, FilerMonitor) ->
receive
{'DOWN', FilerMonitor, _, _, Reason} ->
exit(Reason);
{'EXIT', Parent, Reason} ->
exit(Reason);
Msg ->
Filer ! Msg
end,
relay_loop(Parent, Filer, FilerMonitor).
