inets,tftp: Break out TFTP from inets

- Create directory structure
- Move code, tests, documentation from inets
- Add inets_tftp_wrapper
- Add tftp app to run-dialyzer script

Change-Id: I6a142ae66cecb9a1821cbf9ea6a45f66a836763d

1 files changed, 0 insertions, 1422 deletions

diff --git a/lib/inets/src/tftp/tftp_engine.erl b/lib/inets/src/tftp/tftp_engine.erl
deleted file mode 100644
index fb2c9749e5..0000000000
--- a/lib/inets/src/tftp/tftp_engine.erl
+++ /dev/null
@@ -1,1422 +0,0 @@
-%%
-%% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 2005-2016. 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%
-%% 
-%%-------------------------------------------------------------------
-%% Protocol engine for trivial FTP
-%%-------------------------------------------------------------------
-
--module(tftp_engine).
-
-%%%-------------------------------------------------------------------
-%%% Interface
-%%%-------------------------------------------------------------------
-
-%% application internal functions
--export([
-         daemon_start/1,
-         daemon_loop/1,
-         daemon_loop/3,    %% Handle upgrade from old releases. Please, remove this function in next release.
-         client_start/4,
-         common_loop/6,
-         info/1,
-         change_config/2
-        ]).
-
-%% module internal
--export([
-         daemon_init/1, 
-         server_init/2, 
-         client_init/2,
-         wait_for_msg/3,
-         callback/4
-        ]).
-
-%% sys callback functions
--export([
-         system_continue/3,
-         system_terminate/4,
-         system_code_change/4
-        ]).
-
--include("tftp.hrl").
-
--type prep_status() :: 'error' | 'last' | 'more' | 'terminate'.
-
--record(daemon_state, {config, n_servers, server_tab, file_tab}).
--record(server_info, {pid, req, peer}).
--record(file_info, {peer_req, pid}).
--record(sys_misc, {module, function, arguments}).
--record(error, {where, code, text, filename}).
--record(prepared, {status :: prep_status() | 'undefined',
-                   result, block_no, next_data, prev_data}).
--record(transfer_res, {status, decoded_msg, prepared}).
--define(ERROR(Where, Code, Text, Filename),
-        #error{where = Where, code = Code, text = Text, filename = Filename}).
-
-%%%-------------------------------------------------------------------
-%%% Info
-%%%-------------------------------------------------------------------
-
-info(daemons) ->
-    Daemons = supervisor:which_children(tftp_sup),
-    [{Pid, info(Pid)} || {_, Pid, _, _} <- Daemons];
-info(servers) ->
-    [{Pid, info(Pid)} || {_, {ok, DeamonInfo}} <- info(daemons),
-                         {server, Pid}   <- DeamonInfo];
-info(ToPid) when is_pid(ToPid) ->
-    call(info, ToPid, timer:seconds(10)).
-
-change_config(daemons, Options) ->
-    Daemons = supervisor:which_children(tftp_sup),
-    [{Pid, change_config(Pid, Options)} || {_, Pid, _, _} <- Daemons];
-change_config(servers, Options) ->
-    [{Pid, change_config(Pid, Options)} || {_, {ok, DeamonInfo}} <- info(daemons),
-                                           {server, Pid}   <- DeamonInfo];
-change_config(ToPid, Options) when is_pid(ToPid) ->
-    BadKeys = [host, port, udp],
-    BadOptions = [{Key, Val} || {Key, Val} <- Options,
-                                BadKey <- BadKeys,
-                                Key =:= BadKey],
-    case BadOptions of
-        [] ->
-            call({change_config, Options}, ToPid, timer:seconds(10));
-        [{Key, Val} | _] ->
-            {error, {badarg, {Key, Val}}}
-    end.
-
-call(Req, ToPid, Timeout) when is_pid(ToPid) ->
-    Type = process,
-    Ref = erlang:monitor(Type, ToPid),
-    ToPid ! {Req, Ref, self()},
-    receive
-        {Reply, Ref, FromPid} when FromPid =:= ToPid ->
-            erlang:demonitor(Ref, [flush]),
-            Reply;
-        {'DOWN', Ref, Type, FromPid, _Reason} when FromPid =:= ToPid ->
-            {error, timeout}
-    after Timeout ->
-            {error, timeout}
-    end.
-
-reply(Reply, Ref, ToPid) ->
-    ToPid ! {Reply, Ref, self()}.
-
-%%%-------------------------------------------------------------------
-%%% Daemon
-%%%-------------------------------------------------------------------
-
-%% Returns {ok, Port}
-daemon_start(Options) when is_list(Options) ->
-    Config = tftp_lib:parse_config(Options),
-    proc_lib:start_link(?MODULE, daemon_init, [Config], infinity).
-
-daemon_init(Config) when is_record(Config, config), 
-                         is_pid(Config#config.parent_pid) ->
-    process_flag(trap_exit, true),
-    {Port, UdpOptions} = prepare_daemon_udp(Config),
-    case catch gen_udp:open(Port, UdpOptions) of
-        {ok, Socket} ->
-            {ok, ActualPort} = inet:port(Socket),
-            proc_lib:init_ack({ok, self()}),
-            Config2 = Config#config{udp_socket = Socket,
-                                    udp_port   = ActualPort},
-            print_debug_info(Config2, daemon, open, #tftp_msg_req{filename = ""}),
-            ServerTab = ets:new(tftp_daemon_servers, [{keypos, 2}]),
-            FileTab = ets:new(tftp_daemon_files, [{keypos, 2}]),
-            State = #daemon_state{config = Config2,
-                                  n_servers = 0,
-                                  server_tab = ServerTab,
-                                  file_tab = FileTab},
-            daemon_loop(State);
-        {error, Reason} ->
-            Text = lists:flatten(io_lib:format("UDP open ~p -> ~p", [UdpOptions, Reason])),
-            print_debug_info(Config, daemon, open, ?ERROR(open, undef, Text, "")),
-            exit({gen_udp_open, UdpOptions, Reason});
-        Reason ->
-            Text = lists:flatten(io_lib:format("UDP open ~p -> ~p", [UdpOptions, Reason])),
-            print_debug_info(Config, daemon, open, ?ERROR(open, undef, Text, "")),
-            exit({gen_udp_open, UdpOptions, Reason})
-    end.
-
-prepare_daemon_udp(#config{udp_port = Port, udp_options = UdpOptions} = Config) ->
-    case lists:keymember(fd, 1, UdpOptions) of
-        true ->
-            %% Use explicit fd
-            {Port, UdpOptions};
-        false ->
-            %% Use fd from setuid_socket_wrap, such as -tftpd_69
-            InitArg = list_to_atom("tftpd_" ++ integer_to_list(Port)),
-            case init:get_argument(InitArg) of
-                {ok, [[FdStr]] = Badarg} when is_list(FdStr) ->
-                    case catch list_to_integer(FdStr) of
-                        Fd when is_integer(Fd) ->
-                            {0, [{fd, Fd} | lists:keydelete(ip, 1, UdpOptions)]};
-                        {'EXIT', _} ->
-                            Text = lists:flatten(io_lib:format("Illegal prebound fd ~p: ~p", [InitArg, Badarg])),
-                            print_debug_info(Config, daemon, open, ?ERROR(open, undef, Text, "")),
-                            exit({badarg, {prebound_fd, InitArg, Badarg}})
-                    end;
-                {ok, Badarg} ->
-                    Text = lists:flatten(io_lib:format("Illegal prebound fd ~p: ~p", [InitArg, Badarg])),
-                    print_debug_info(Config, daemon, open, ?ERROR(open, undef, Text, "")),
-                    exit({badarg, {prebound_fd, InitArg, Badarg}});
-                error ->
-                    {Port, UdpOptions}
-            end
-    end.
-
-daemon_loop(DaemonConfig, N, Servers) when is_list(Servers) ->
-    %% Handle upgrade from old releases. Please, remove this function in next release.
-    ServerTab = ets:new(tftp_daemon_servers, [{keypos, 2}]),
-    FileTab = ets:new(tftp_daemon_files, [{keypos, 2}]),
-    State = #daemon_state{config = DaemonConfig,
-                          n_servers = N,
-                          server_tab = ServerTab,
-                          file_tab = FileTab},
-    Req = #tftp_msg_req{filename = dummy},
-    [ets:insert(ServerTab, #server_info{pid = Pid, req = Req, peer = dummy}) || Pid <- Servers],
-    daemon_loop(State).
-
-daemon_loop(#daemon_state{config = DaemonConfig,
-                          n_servers = N,
-                          server_tab = ServerTab,
-                          file_tab = FileTab} = State) when is_record(DaemonConfig, config) ->
-    %% info_msg(DaemonConfig, "=====> TFTP: Daemon #~p\n", [N]), %% XXX
-    receive
-        {info, Ref, FromPid} when is_pid(FromPid) ->
-            Fun = fun(#server_info{pid = Pid}, Acc) -> [{server, Pid} | Acc] end,
-            ServerInfo = ets:foldl(Fun, [], ServerTab),
-            Info = internal_info(DaemonConfig, daemon) ++ [{n_conn, N}] ++ ServerInfo,
-            reply({ok, Info}, Ref, FromPid),
-            ?MODULE:daemon_loop(State);
-        {{change_config, Options}, Ref, FromPid} when is_pid(FromPid) ->
-            case catch tftp_lib:parse_config(Options, DaemonConfig) of
-                {'EXIT', Reason} ->
-                    reply({error, Reason}, Ref, FromPid),
-                    ?MODULE:daemon_loop(State);
-                DaemonConfig2 when is_record(DaemonConfig2, config) ->
-                    reply(ok, Ref, FromPid),
-                    ?MODULE:daemon_loop(State#daemon_state{config = DaemonConfig2})
-            end;
-        {udp, Socket, RemoteHost, RemotePort, Bin} when is_binary(Bin) ->
-            inet:setopts(Socket, [{active, once}]),
-            ServerConfig = DaemonConfig#config{parent_pid = self(),
-                                               udp_host   = RemoteHost,
-                                               udp_port   = RemotePort},
-            Msg = (catch tftp_lib:decode_msg(Bin)),
-            print_debug_info(ServerConfig, daemon, recv, Msg),
-            case Msg of
-                Req when is_record(Req, tftp_msg_req), 
-                N =< DaemonConfig#config.max_conn ->
-                    Peer = peer_info(ServerConfig),
-                    PeerReq = {Peer, Req},
-                    PeerInfo = lists:flatten(io_lib:format("~p", [Peer])),
-                    case ets:lookup(FileTab, PeerReq) of
-                        [] ->
-                            Args = [ServerConfig, Req],
-                            Pid = proc_lib:spawn_link(?MODULE, server_init, Args),
-                            ets:insert(ServerTab, #server_info{pid = Pid, req = Req, peer = Peer}),
-                            ets:insert(FileTab, #file_info{peer_req = PeerReq, pid = Pid}),
-                            ?MODULE:daemon_loop(State#daemon_state{n_servers = N + 1});
-                        [#file_info{pid = Pid}] ->
-                            %% Yet another request of the file from same peer
-                            warning_msg(DaemonConfig, "~p Reuse connection for ~s\n\t~p\n",
-                                        [Pid, PeerInfo, Req#tftp_msg_req.filename]),
-                            ?MODULE:daemon_loop(State)
-                    end;
-                Req when is_record(Req, tftp_msg_req) ->
-                    Reply = #tftp_msg_error{code = enospc, text = "Too many connections"},
-                    Peer = peer_info(ServerConfig),
-                    PeerInfo = lists:flatten(io_lib:format("~p", [Peer])),
-                    warning_msg(DaemonConfig, 
-				"Daemon has too many connections (~p)."
-				"\n\tRejecting request from ~s\n",
-				[N, PeerInfo]),
-                    send_msg(ServerConfig, daemon, Reply),
-                    ?MODULE:daemon_loop(State);
-                {'EXIT', Reply} when is_record(Reply, tftp_msg_error) ->
-                    send_msg(ServerConfig, daemon, Reply),
-                    ?MODULE:daemon_loop(State);
-                Req  ->
-                    Reply = #tftp_msg_error{code = badop,
-                                            text = "Illegal TFTP operation"},
-                    warning_msg(DaemonConfig, "Daemon received: ~p.\n\tfrom ~p:~p", 
-                                [Req, RemoteHost, RemotePort]),
-                    send_msg(ServerConfig, daemon, Reply),
-                    ?MODULE:daemon_loop(State)
-            end;
-        {system, From, Msg} ->
-            Misc = #sys_misc{module = ?MODULE, function = daemon_loop, arguments = [State]},
-            sys:handle_system_msg(Msg, From, DaemonConfig#config.parent_pid, ?MODULE, [], Misc);
-        {'EXIT', Pid, Reason} when DaemonConfig#config.parent_pid =:= Pid ->
-            close_port(DaemonConfig, daemon, #tftp_msg_req{filename = ""}),
-            exit(Reason);
-        {'EXIT', Pid, _Reason} = Info ->
-            case ets:lookup(ServerTab, Pid) of
-                [] ->
-                    warning_msg(DaemonConfig, "Daemon received: ~p", [Info]),
-                    ?MODULE:daemon_loop(State);
-                [#server_info{req = Req, peer = Peer}] ->
-                    PeerReq = {Peer, Req},
-                    ets:delete(FileTab, PeerReq),
-                    ets:delete(ServerTab, Pid),
-                    ?MODULE:daemon_loop(State#daemon_state{n_servers = N - 1})
-            end;
-        Info ->
-            warning_msg(DaemonConfig, "Daemon received: ~p", [Info]),
-            ?MODULE:daemon_loop(State)
-    end;
-daemon_loop(#daemon_state{config = Config} = State) ->
-    %% Handle upgrade from old releases. Please, remove this clause in next release.
-    Config2 = upgrade_config(Config),
-    daemon_loop(State#daemon_state{config = Config2}).
-
-upgrade_config({config, ParentPid, UdpSocket, UdpOptions, UdpHost, UdpPort, PortPolicy,
-                UseTsize, MaxTsize, MaxConn, Rejected, PoliteAck, DebugLevel,
-                Timeout, UserOptions, Callbacks}) ->
-    Callbacks2  = tftp_lib:add_default_callbacks(Callbacks),
-    Logger = tftp_logger,
-    MaxRetries = 5,
-    {config, ParentPid, UdpSocket, UdpOptions, UdpHost, UdpPort, PortPolicy,
-     UseTsize, MaxTsize, MaxConn, Rejected, PoliteAck, DebugLevel,
-     Timeout, UserOptions, Callbacks2, Logger, MaxRetries}.
-
-%%%-------------------------------------------------------------------
-%%% Server
-%%%-------------------------------------------------------------------
-
-server_init(Config, Req) when is_record(Config, config),
-                              is_pid(Config#config.parent_pid),
-                              is_record(Req, tftp_msg_req) ->
-    process_flag(trap_exit, true),
-    %% Config = 
-    %%     case os:getenv("TFTPDEBUG") of
-    %%         false ->
-    %%             Config0;
-    %%         DebugLevel ->
-    %%             Config0#config{debug_level = list_to_atom(DebugLevel)}
-    %%     end,
-    SuggestedOptions = Req#tftp_msg_req.options,
-    UdpOptions = Config#config.udp_options,
-    UdpOptions2 = lists:keydelete(fd, 1, UdpOptions),
-    Config1 = Config#config{udp_options = UdpOptions2},
-    Config2 = tftp_lib:parse_config(SuggestedOptions, Config1),
-    SuggestedOptions2 = Config2#config.user_options,
-    Req2 = Req#tftp_msg_req{options = SuggestedOptions2},
-    case open_free_port(Config2, server, Req2) of
-        {ok, Config3} ->
-            Filename = Req#tftp_msg_req.filename,
-            case match_callback(Filename, Config3#config.callbacks) of
-                {ok, Callback} ->
-                    print_debug_info(Config3, server, match, Callback),
-                    case pre_verify_options(Config3, Req2) of
-                        ok ->
-                            case callback({open, server_open}, Config3, Callback, Req2) of
-                                {Callback2, {ok, AcceptedOptions}} ->
-                                    {LocalAccess,  _} = local_file_access(Req2),
-                                    OptText = "Internal error. Not allowed to add new options.",
-                                    case post_verify_options(Config3, Req2, AcceptedOptions, OptText) of
-                                        {ok, Config4, Req3} when AcceptedOptions =/= [] ->
-                                            Reply = #tftp_msg_oack{options = AcceptedOptions},
-                                            BlockNo =
-                                                case LocalAccess of
-                                                    read  -> 0;
-                                                    write -> 1
-                                                end,
-                                            {Config5, Callback3, TransferRes} = 
-                                                transfer(Config4, Callback2, Req3, Reply, LocalAccess, BlockNo, #prepared{}),
-                                            common_loop(Config5, Callback3, Req3, TransferRes, LocalAccess, BlockNo);
-                                        {ok, Config4, Req3} when LocalAccess =:= write ->
-                                            BlockNo = 0,
-                                            common_ack(Config4, Callback2, Req3, LocalAccess, BlockNo, #prepared{});
-                                        {ok, Config4, Req3} when LocalAccess =:= read ->
-                                            BlockNo = 0,
-                                            common_read(Config4, Callback2, Req3, LocalAccess, BlockNo, BlockNo, #prepared{});
-                                        {error, {Code, Text}} ->
-                                            {undefined, Error} =
-                                                callback({abort, {Code, Text}}, Config3, Callback2, Req2),
-                                            send_msg(Config3, Req, Error),
-                                            terminate(Config3, Req2, ?ERROR(post_verify_options, Code, Text, Req2#tftp_msg_req.filename))
-                                    end;
-                                {undefined, #tftp_msg_error{code = Code, text = Text} = Error} ->
-                                    send_msg(Config3, Req, Error),
-                                    terminate(Config3, Req, ?ERROR(server_open, Code, Text, Req2#tftp_msg_req.filename))
-                            end;
-                        {error, {Code, Text}} ->
-                            {undefined, Error} =
-                                callback({abort, {Code, Text}}, Config2, Callback, Req2),
-                            send_msg(Config2, Req, Error),
-                            terminate(Config2, Req2, ?ERROR(pre_verify_options, Code, Text, Req2#tftp_msg_req.filename))
-                    end;
-                {error, #tftp_msg_error{code = Code, text = Text} = Error} ->
-                    send_msg(Config3, Req, Error),
-                    terminate(Config3, Req, ?ERROR(match_callback, Code, Text, Req2#tftp_msg_req.filename))
-            end;
-        #error{} = Error ->
-            terminate(Config2, Req, Error)
-    end;
-server_init(Config, Req) when is_record(Req, tftp_msg_req) ->
-    Config2 = upgrade_config(Config),
-    server_init(Config2, Req).
-
-%%%-------------------------------------------------------------------
-%%% Client
-%%%-------------------------------------------------------------------
-
-%% LocalFilename = filename() | 'binary' | binary()
-%% Returns {ok, LastCallbackState} | {error, Reason}
-client_start(Access, RemoteFilename, LocalFilename, Options) ->
-    Config = tftp_lib:parse_config(Options),
-    Config2 = Config#config{parent_pid      = self(),
-                            udp_socket      = undefined},
-    Req = #tftp_msg_req{access         = Access, 
-                        filename       = RemoteFilename, 
-                        mode           = lookup_mode(Config2#config.user_options),
-                        options        = Config2#config.user_options,
-                        local_filename = LocalFilename},
-    Args = [Config2, Req],
-    case proc_lib:start_link(?MODULE, client_init, Args, infinity) of
-        {ok, LastCallbackState} ->
-            {ok, LastCallbackState};
-        {error, Error} ->
-            {error, Error}
-    end.
-
-client_init(Config, Req) when is_record(Config, config),
-                              is_pid(Config#config.parent_pid),
-                              is_record(Req, tftp_msg_req) ->
-    process_flag(trap_exit, true),
-    %% Config = 
-    %%  case os:getenv("TFTPDEBUG") of
-    %%      false ->
-    %%          Config0;
-    %%      "none" ->
-    %%          Config0;
-    %%      DebugLevel ->
-    %%          info_msg(Config, "TFTPDEBUG: ~s\n", [DebugLevel]),
-    %%          Config0#config{debug_level = list_to_atom(DebugLevel)}
-    %%  end,
-    case open_free_port(Config, client, Req) of
-        {ok, Config2} ->
-            Req2 =
-                case Config2#config.use_tsize of
-                    true ->
-                        SuggestedOptions = Req#tftp_msg_req.options,
-                        SuggestedOptions2 = tftp_lib:replace_val("tsize", "0", SuggestedOptions),
-                        Req#tftp_msg_req{options = SuggestedOptions2};
-                    false ->
-                        Req
-                end,
-            LocalFilename = Req2#tftp_msg_req.local_filename,
-            case match_callback(LocalFilename, Config2#config.callbacks) of
-                {ok, Callback} ->
-                    print_debug_info(Config2, client, match, Callback),
-                    client_prepare(Config2, Callback, Req2);                
-                {error, #tftp_msg_error{code = Code, text = Text}} ->
-                    terminate(Config, Req, ?ERROR(match, Code, Text, Req#tftp_msg_req.filename))
-            end;
-        #error{} = Error ->
-            terminate(Config, Req, Error)
-    end.
-
-client_prepare(Config, Callback, Req) when is_record(Req, tftp_msg_req) ->
-    case pre_verify_options(Config, Req) of
-        ok ->
-            case callback({open, client_prepare}, Config, Callback, Req) of
-                {Callback2, {ok, AcceptedOptions}} ->
-                    OptText = "Internal error. Not allowed to add new options.",
-                    case post_verify_options(Config, Req, AcceptedOptions, OptText) of
-                        {ok, Config2, Req2} ->
-                            {LocalAccess, _} = local_file_access(Req2),
-                            BlockNo = 0,
-                            {Config3, Callback3, TransferRes} =
-                                transfer(Config2, Callback2, Req2, Req2, LocalAccess, BlockNo, #prepared{}),
-                            client_open(Config3, Callback3, Req2, BlockNo, TransferRes);
-                        {error, {Code, Text}} ->
-                            callback({abort, {Code, Text}}, Config, Callback2, Req),
-                            terminate(Config, Req, ?ERROR(post_verify_options, Code, Text, Req#tftp_msg_req.filename))
-                    end;
-                {undefined, #tftp_msg_error{code = Code, text = Text}} ->
-                    terminate(Config, Req, ?ERROR(client_prepare, Code, Text, Req#tftp_msg_req.filename))
-            end;
-        {error, {Code, Text}} ->
-            callback({abort, {Code, Text}}, Config, Callback, Req),
-            terminate(Config, Req, ?ERROR(pre_verify_options, Code, Text, Req#tftp_msg_req.filename))
-    end.
-
-client_open(Config, Callback, Req, BlockNo, #transfer_res{status = Status, decoded_msg = DecodedMsg, prepared = Prepared}) ->
-    {LocalAccess, _} = local_file_access(Req),
-    case Status of
-        ok when is_record(Prepared, prepared) ->
-            case DecodedMsg of
-                Msg when is_record(Msg, tftp_msg_oack) ->
-                    ServerOptions = Msg#tftp_msg_oack.options,
-                    OptText = "Protocol violation. Server is not allowed new options",
-                    case post_verify_options(Config, Req, ServerOptions, OptText) of
-                        {ok, Config2, Req2} ->              
-                            {Config3, Callback2, Req3} =
-                                do_client_open(Config2, Callback, Req2),
-                            case LocalAccess of
-                                read ->
-                                    common_read(Config3, Callback2, Req3, LocalAccess, BlockNo, BlockNo, Prepared);
-                                write ->
-                                    common_ack(Config3, Callback2, Req3, LocalAccess, BlockNo, Prepared)
-                            end;
-                        {error, {Code, Text}} ->
-                            {undefined, Error} =
-                                callback({abort, {Code, Text}}, Config, Callback, Req),
-                            send_msg(Config, Req, Error),
-                            terminate(Config, Req, ?ERROR(verify_server_options, Code, Text, Req#tftp_msg_req.filename))
-                    end;
-                #tftp_msg_ack{block_no = ActualBlockNo} when LocalAccess =:= read ->
-                    Req2 = Req#tftp_msg_req{options = []},
-                    {Config2, Callback2, Req2} = do_client_open(Config, Callback, Req2),
-                    ExpectedBlockNo = 0,
-                    common_read(Config2, Callback2, Req2, LocalAccess, ExpectedBlockNo, ActualBlockNo, Prepared);
-                #tftp_msg_data{block_no = ActualBlockNo, data = Data} when LocalAccess =:= write ->
-                    Req2 = Req#tftp_msg_req{options = []},
-                    {Config2, Callback2, Req2} = do_client_open(Config, Callback, Req2),
-                    ExpectedBlockNo = 1,
-                    common_write(Config2, Callback2, Req2, LocalAccess, ExpectedBlockNo, ActualBlockNo, Data, Prepared);
-                %% #tftp_msg_error{code = Code, text = Text} when Req#tftp_msg_req.options =/= [] ->
-                %%     %% Retry without options
-                %%     callback({abort, {Code, Text}}, Config, Callback, Req),
-                %%     Req2 = Req#tftp_msg_req{options = []},
-                %%     client_prepare(Config, Callback, Req2);
-                #tftp_msg_error{code = Code, text = Text} ->
-                    callback({abort, {Code, Text}}, Config, Callback, Req),
-                    terminate(Config, Req, ?ERROR(client_open, Code, Text, Req#tftp_msg_req.filename));
-                {'EXIT', #tftp_msg_error{code = Code, text = Text}} ->
-                    callback({abort, {Code, Text}}, Config, Callback, Req),
-                    terminate(Config, Req, ?ERROR(client_open, Code, Text, Req#tftp_msg_req.filename));
-                Msg when is_tuple(Msg) ->
-                    Code = badop,
-                    Text = "Illegal TFTP operation",
-                    {undefined, Error} =
-                        callback({abort, {Code, Text}}, Config, Callback, Req),
-                    send_msg(Config, Req, Error),
-                    Text2 = lists:flatten([Text, ". ", io_lib:format("~p", [element(1, Msg)])]),
-                    terminate(Config, Req, ?ERROR(client_open, Code, Text2, Req#tftp_msg_req.filename))
-            end;
-        error when is_record(Prepared, tftp_msg_error) ->
-            #tftp_msg_error{code = Code, text = Text} = Prepared,
-            callback({abort, {Code, Text}}, Config, Callback, Req),
-            terminate(Config, Req, ?ERROR(client_open, Code, Text, Req#tftp_msg_req.filename))
-    end.
-
-do_client_open(Config, Callback, Req) ->
-    case callback({open, client_open}, Config, Callback, Req) of
-        {Callback2, {ok, FinalOptions}} ->
-            OptText = "Internal error. Not allowed to change options.",
-            case post_verify_options(Config, Req, FinalOptions, OptText) of
-                {ok, Config2, Req2} ->
-                    {Config2, Callback2, Req2};
-                {error, {Code, Text}} ->
-                    {undefined, Error} =
-                        callback({abort, {Code, Text}}, Config, Callback2, Req),
-                    send_msg(Config, Req, Error),
-                    terminate(Config, Req, ?ERROR(post_verify_options, Code, Text, Req#tftp_msg_req.filename))
-            end;
-        {undefined, #tftp_msg_error{code = Code, text = Text} = Error} ->
-            send_msg(Config, Req, Error),
-            terminate(Config, Req, ?ERROR(client_open, Code, Text, Req#tftp_msg_req.filename))
-    end.
-
-%%%-------------------------------------------------------------------
-%%% Common loop for both client and server
-%%%-------------------------------------------------------------------
-
-common_loop(Config, Callback, Req, #transfer_res{status = Status, decoded_msg = DecodedMsg, prepared = Prepared}, LocalAccess, ExpectedBlockNo) 
-  when is_record(Config, config)->
-    %%    Config =
-    %%  case os:getenv("TFTPMAX") of
-    %%      false -> 
-    %%          Config0;
-    %%      MaxBlockNoStr when Config0#config.debug_level =/= none ->
-    %%          case list_to_integer(MaxBlockNoStr) of
-    %%              MaxBlockNo when ExpectedBlockNo > MaxBlockNo ->
-    %%                  info_msg(Config, "TFTPMAX: ~p\n", [MaxBlockNo]),
-    %%                  info_msg(Config, "TFTPDEBUG: none\n", []),
-    %%                  Config0#config{debug_level = none};
-    %%              _ ->
-    %%                  Config0
-    %%          end;
-    %%      _MaxBlockNoStr ->
-    %%          Config0 
-    %%  end,
-    case Status of
-        ok when is_record(Prepared, prepared) ->
-            case DecodedMsg of
-                #tftp_msg_ack{block_no = ActualBlockNo} when LocalAccess =:= read ->
-                    common_read(Config, Callback, Req, LocalAccess, ExpectedBlockNo, ActualBlockNo, Prepared);
-                #tftp_msg_data{block_no = ActualBlockNo, data = Data} when LocalAccess =:= write ->
-                    common_write(Config, Callback, Req, LocalAccess, ExpectedBlockNo, ActualBlockNo, Data, Prepared);
-                #tftp_msg_error{code = Code, text = Text} ->
-                    callback({abort, {Code, Text}}, Config, Callback, Req),
-                    terminate(Config, Req, ?ERROR(common_loop, Code, Text, Req#tftp_msg_req.filename));
-                {'EXIT', #tftp_msg_error{code = Code, text = Text} = Error} ->
-                    callback({abort, {Code, Text}}, Config, Callback, Req),
-                    send_msg(Config, Req, Error),
-                    terminate(Config, Req, ?ERROR(common_loop, Code, Text, Req#tftp_msg_req.filename));
-                Msg when is_tuple(Msg) ->
-                    Code = badop,
-                    Text = "Illegal TFTP operation",
-                    {undefined, Error} =
-                        callback({abort, {Code, Text}}, Config, Callback, Req),
-                    send_msg(Config, Req, Error),
-                    Text2 = lists:flatten([Text, ". ", io_lib:format("~p", [element(1, Msg)])]),
-                    terminate(Config, Req, ?ERROR(common_loop, Code, Text2, Req#tftp_msg_req.filename))
-            end;
-        error when is_record(Prepared, tftp_msg_error) ->
-            #tftp_msg_error{code = Code, text = Text} = Prepared,
-            send_msg(Config, Req, Prepared),
-            terminate(Config, Req, ?ERROR(transfer, Code, Text, Req#tftp_msg_req.filename))
-    end;
-common_loop(Config, Callback, Req, TransferRes, LocalAccess, ExpectedBlockNo) ->
-    %% Handle upgrade from old releases. Please, remove this clause in next release.
-    Config2 = upgrade_config(Config),
-    common_loop(Config2, Callback, Req, TransferRes, LocalAccess, ExpectedBlockNo).
-
--spec common_read(#config{}, #callback{}, _, 'read', _, _, #prepared{}) -> no_return().
-
-common_read(Config, _, Req, _, _, _, #prepared{status = terminate, result = Result}) ->
-    terminate(Config, Req, {ok, Result});
-common_read(Config, Callback, Req, LocalAccess, ExpectedBlockNo, ActualBlockNo, Prepared)
-  when ActualBlockNo =:= ExpectedBlockNo, is_record(Prepared, prepared) ->
-    case early_read(Config, Callback, Req, LocalAccess, ActualBlockNo, Prepared) of
-        {Callback2,  #prepared{status = more, next_data = Data} = Prepared2} when is_binary(Data) ->
-            Prepared3 = Prepared2#prepared{prev_data = Data, next_data = undefined},
-            do_common_read(Config, Callback2, Req, LocalAccess, ActualBlockNo, Data, Prepared3);
-        {undefined, #prepared{status = last, next_data = Data} = Prepared2} when is_binary(Data) ->
-            Prepared3 = Prepared2#prepared{status = terminate},
-            do_common_read(Config, undefined, Req, LocalAccess, ActualBlockNo, Data, Prepared3);
-        {undefined, #prepared{status = error, result = Error}} ->
-            #tftp_msg_error{code = Code, text = Text} = Error,
-            send_msg(Config, Req, Error),
-            terminate(Config, Req, ?ERROR(read, Code, Text, Req#tftp_msg_req.filename))
-    end;
-common_read(Config, Callback, Req, LocalAccess, ExpectedBlockNo, ActualBlockNo, Prepared) 
-  when ActualBlockNo =:= (ExpectedBlockNo - 1), is_record(Prepared, prepared) ->
-    case Prepared of
-        #prepared{status = more, prev_data = Data} when is_binary(Data) ->
-            do_common_read(Config, Callback, Req, LocalAccess, ActualBlockNo, Data, Prepared);
-        #prepared{status = last, prev_data = Data} when is_binary(Data) ->
-            do_common_read(Config, Callback, Req, LocalAccess, ActualBlockNo, Data, Prepared);
-        #prepared{status = error, result = Error} ->
-            #tftp_msg_error{code = Code, text = Text} = Error,
-            send_msg(Config, Req, Error),
-            terminate(Config, Req, ?ERROR(read, Code, Text, Req#tftp_msg_req.filename))
-    end;
-common_read(Config, Callback, Req, LocalAccess, ExpectedBlockNo, ActualBlockNo, Prepared) 
-  when ActualBlockNo =< ExpectedBlockNo, is_record(Prepared, prepared) ->
-    %% error_logger:error_msg("TFTP READ ~s: Expected block ~p but got block ~p - IGNORED\n",
-    %%                     [Req#tftp_msg_req.filename, ExpectedBlockNo, ActualBlockNo]),
-    case Prepared of
-        #prepared{status = more, prev_data = Data} when is_binary(Data) ->
-            Reply = #tftp_msg_data{block_no = ExpectedBlockNo, data = Data},
-            {Config2, Callback2, TransferRes} =
-                wait_for_msg_and_handle_timeout(Config, Callback, Req, Reply, LocalAccess, ExpectedBlockNo, Prepared),
-            ?MODULE:common_loop(Config2, Callback2, Req, TransferRes, LocalAccess, ExpectedBlockNo);
-        #prepared{status = last, prev_data = Data} when is_binary(Data) ->
-            Reply = #tftp_msg_data{block_no = ExpectedBlockNo, data = Data},
-            {Config2, Callback2, TransferRes} =
-                wait_for_msg_and_handle_timeout(Config, Callback, Req, Reply, LocalAccess, ExpectedBlockNo, Prepared),
-            ?MODULE:common_loop(Config2, Callback2, Req, TransferRes, LocalAccess, ExpectedBlockNo);
-        #prepared{status = error, result = Error} ->
-            #tftp_msg_error{code = Code, text = Text} = Error,
-            send_msg(Config, Req, Error),
-            terminate(Config, Req, ?ERROR(read, Code, Text, Req#tftp_msg_req.filename))
-    end;
-common_read(Config, Callback, Req, _LocalAccess, ExpectedBlockNo, ActualBlockNo, Prepared)
-  when is_record(Prepared, prepared) ->
-    Code = badblk,
-    Text = "Unknown transfer ID = " ++ 
-        integer_to_list(ActualBlockNo) ++ " (" ++ integer_to_list(ExpectedBlockNo) ++ ")", 
-    {undefined, Error} =
-        callback({abort, {Code, Text}}, Config, Callback, Req),
-    send_msg(Config, Req, Error),
-    terminate(Config, Req, ?ERROR(read, Code, Text, Req#tftp_msg_req.filename)).
-
--spec do_common_read(#config{}, #callback{} | undefined, _, 'read', integer(), binary(), #prepared{}) -> no_return().
-
-do_common_read(Config, Callback, Req, LocalAccess, BlockNo, Data, Prepared)
-  when is_binary(Data), is_record(Prepared, prepared) ->
-    NextBlockNo = (BlockNo + 1) rem 65536,
-    Reply = #tftp_msg_data{block_no = NextBlockNo, data = Data},
-    {Config2, Callback2, TransferRes} =
-        transfer(Config, Callback, Req, Reply, LocalAccess, NextBlockNo, Prepared),
-    ?MODULE:common_loop(Config2, Callback2, Req, TransferRes, LocalAccess, NextBlockNo).
-
--spec common_write(#config{}, #callback{}, _, 'write', integer(), integer(), _, #prepared{}) -> no_return().
-
-common_write(Config, _, Req, _, _, _, _, #prepared{status = terminate, result = Result}) ->
-    terminate(Config, Req, {ok, Result});
-common_write(Config, Callback, Req, LocalAccess, ExpectedBlockNo, ActualBlockNo, Data, Prepared)
-  when ActualBlockNo =:= ExpectedBlockNo, is_binary(Data), is_record(Prepared, prepared) ->
-    case callback({write, Data}, Config, Callback, Req) of
-        {Callback2, #prepared{status = more} = Prepared2} ->
-            common_ack(Config, Callback2, Req, LocalAccess, ActualBlockNo, Prepared2);
-        {undefined, #prepared{status = last, result = Result} = Prepared2} ->
-            Config2 = pre_terminate(Config, Req, {ok, Result}),
-            Prepared3 = Prepared2#prepared{status = terminate},
-            common_ack(Config2, undefined, Req, LocalAccess, ActualBlockNo, Prepared3);
-        {undefined, #prepared{status = error, result = Error}} ->
-            #tftp_msg_error{code = Code, text = Text} = Error,
-            send_msg(Config, Req, Error),
-            terminate(Config, Req, ?ERROR(write, Code, Text, Req#tftp_msg_req.filename))
-    end;
-common_write(Config, Callback, Req, LocalAccess, ExpectedBlockNo, ActualBlockNo, Data, Prepared)
-  when ActualBlockNo =:= (ExpectedBlockNo - 1), is_binary(Data), is_record(Prepared, prepared) ->
-    common_ack(Config, Callback, Req, LocalAccess, ExpectedBlockNo - 1, Prepared);
-common_write(Config, Callback, Req, LocalAccess, ExpectedBlockNo, ActualBlockNo, Data, Prepared)
-  when ActualBlockNo =< ExpectedBlockNo, is_binary(Data), is_record(Prepared, prepared) ->
-    %% error_logger:error_msg("TFTP WRITE ~s: Expected block ~p but got block ~p - IGNORED\n",
-    %% [Req#tftp_msg_req.filename, ExpectedBlockNo, ActualBlockNo]),
-    Reply = #tftp_msg_ack{block_no = ExpectedBlockNo},
-    {Config2, Callback2, TransferRes} = 
-        wait_for_msg_and_handle_timeout(Config, Callback, Req, Reply, LocalAccess, ExpectedBlockNo, Prepared),
-    ?MODULE:common_loop(Config2, Callback2, Req, TransferRes, LocalAccess, ExpectedBlockNo);
-common_write(Config, Callback, Req, _, ExpectedBlockNo, ActualBlockNo, Data, Prepared)
-  when is_binary(Data), is_record(Prepared, prepared) ->
-    Code = badblk,
-    Text = "Unknown transfer ID = " ++ 
-        integer_to_list(ActualBlockNo) ++ " (" ++ integer_to_list(ExpectedBlockNo) ++ ")", 
-    {undefined, Error} =
-        callback({abort, {Code, Text}}, Config, Callback, Req),
-    send_msg(Config, Req, Error),
-    terminate(Config, Req, ?ERROR(write, Code, Text, Req#tftp_msg_req.filename)).
-
-common_ack(Config, Callback, Req, LocalAccess, BlockNo, Prepared) 
-  when is_record(Prepared, prepared) ->
-    Reply = #tftp_msg_ack{block_no = BlockNo},
-    NextBlockNo = (BlockNo + 1) rem 65536,
-    {Config2, Callback2, TransferRes} = 
-        transfer(Config, Callback, Req, Reply, LocalAccess, NextBlockNo, Prepared),
-    ?MODULE:common_loop(Config2, Callback2, Req, TransferRes, LocalAccess, NextBlockNo).
-
-pre_terminate(Config, Req, Result) ->
-    if
-        Req#tftp_msg_req.local_filename =/= undefined,
-        Config#config.parent_pid =/= undefined ->
-            proc_lib:init_ack(Result),
-            unlink(Config#config.parent_pid),
-            Config#config{parent_pid = undefined, polite_ack = true};
-        true ->
-            Config#config{polite_ack = true}
-    end.
-
--spec terminate(#config{}, #tftp_msg_req{}, {'ok', _} | #error{}) -> no_return().
-
-terminate(Config, Req, Result) ->
-    Result2 =
-        case Result of
-            {ok, _} ->
-                Result;
-            #error{where = Where, code = Code, text = Text} = Error ->
-                print_debug_info(Config, Req, Where, Error#error{filename = Req#tftp_msg_req.filename}),
-                {error, {Where, Code, Text}}
-        end,  
-    if
-        Config#config.parent_pid =:= undefined ->
-            close_port(Config, client, Req),
-            exit(normal);
-        Req#tftp_msg_req.local_filename =/= undefined  ->
-            %% Client
-            close_port(Config, client, Req),
-            proc_lib:init_ack(Result2),
-            unlink(Config#config.parent_pid),
-            exit(normal);
-        true ->
-            %% Server
-            close_port(Config, server, Req),
-            exit(shutdown)                  
-    end.
-
-close_port(Config, Who, Req) when is_record(Req, tftp_msg_req) ->
-    case Config#config.udp_socket of
-        undefined -> 
-            ignore;
-        Socket    -> 
-            print_debug_info(Config, Who, close, Req),
-            gen_udp:close(Socket)
-    end.
-
-open_free_port(Config, Who, Req) when is_record(Config, config), is_record(Req, tftp_msg_req) ->
-    UdpOptions = Config#config.udp_options,
-    case Config#config.port_policy of
-        random ->
-            %% BUGBUG: Should be a random port
-            case catch gen_udp:open(0, UdpOptions) of
-                {ok, Socket} ->
-                    Config2 = Config#config{udp_socket = Socket},
-                    print_debug_info(Config2, Who, open, Req),
-                    {ok, Config2};
-                {error, Reason} ->
-                    Text = lists:flatten(io_lib:format("UDP open ~p -> ~p", [[0 | UdpOptions], Reason])),
-                    ?ERROR(open, undef, Text, Req#tftp_msg_req.filename);
-                {'EXIT', _} = Reason ->
-                    Text = lists:flatten(io_lib:format("UDP open ~p -> ~p", [[0 | UdpOptions], Reason])),
-                    ?ERROR(open, undef, Text, Req#tftp_msg_req.filename)
-            end;
-        {range, Port, Max} when Port =< Max ->
-            case catch gen_udp:open(Port, UdpOptions) of
-                {ok, Socket} ->
-                    Config2 = Config#config{udp_socket = Socket},
-                    print_debug_info(Config2, Who, open, Req),
-                    {ok, Config2};
-                {error, eaddrinuse} ->
-                    PortPolicy = {range, Port + 1, Max},
-                    Config2 = Config#config{port_policy = PortPolicy},
-                    open_free_port(Config2, Who, Req);
-                {error, Reason} ->
-                    Text = lists:flatten(io_lib:format("UDP open ~p -> ~p", [[Port | UdpOptions], Reason])),
-                    ?ERROR(open, undef, Text, Req#tftp_msg_req.filename);
-                {'EXIT', _} = Reason->
-                    Text = lists:flatten(io_lib:format("UDP open ~p -> ~p", [[Port | UdpOptions], Reason])),
-                    ?ERROR(open, undef, Text, Req#tftp_msg_req.filename)
-            end;
-        {range, Port, _Max} ->
-            Reason = "Port range exhausted",
-            Text = lists:flatten(io_lib:format("UDP open ~p -> ~p", [[Port | UdpOptions], Reason])),
-            ?ERROR(Who, undef, Text, Req#tftp_msg_req.filename)
-    end.
-
-%%-------------------------------------------------------------------
-%% Transfer
-%%-------------------------------------------------------------------
-
-%% Returns {Config, Callback, #transfer_res{}}
-transfer(Config, Callback, Req, Msg, LocalAccess, NextBlockNo, Prepared) 
-  when is_record(Prepared, prepared) ->
-    IoList = tftp_lib:encode_msg(Msg),
-    Retries = Config#config.max_retries + 1,
-    do_transfer(Config, Callback, Req, Msg, IoList, LocalAccess, NextBlockNo, Prepared, Retries).
-
-do_transfer(Config, Callback, Req, Msg, IoList, LocalAccess, NextBlockNo, Prepared, Retries)
-  when is_record(Prepared, prepared), is_integer(Retries), Retries >= 0 ->
-    case do_send_msg(Config, Req, Msg, IoList) of
-        ok ->
-            {Callback2, Prepared2} = 
-                early_read(Config, Callback, Req, LocalAccess, NextBlockNo, Prepared),
-            do_wait_for_msg_and_handle_timeout(Config, Callback2, Req, Msg, IoList, LocalAccess, NextBlockNo, Prepared2, Retries);
-        {error, _Reason} when Retries > 0 ->
-            Retries2 = 0, % Just retry once when send fails
-            do_transfer(Config, Callback, Req, Msg, IoList, LocalAccess, NextBlockNo, Prepared, Retries2);
-        {error, Reason} ->
-            Code = undef,
-            Text = lists:flatten(io_lib:format("Transfer failed - giving up -> ~p", [Reason])),
-            Error = #tftp_msg_error{code = Code, text = Text},
-            {Config, Callback, #transfer_res{status = error, prepared = Error}}
-    end.
-
-wait_for_msg_and_handle_timeout(Config, Callback, Req, Msg, LocalAccess, NextBlockNo, Prepared) ->
-    IoList = tftp_lib:encode_msg(Msg),
-    Retries = Config#config.max_retries + 1,
-    do_wait_for_msg_and_handle_timeout(Config, Callback, Req, Msg, IoList, LocalAccess, NextBlockNo, Prepared, Retries).
-
-do_wait_for_msg_and_handle_timeout(Config, Callback, Req, Msg, IoList, LocalAccess, NextBlockNo, Prepared, Retries) ->
-    Code = undef,
-    Text = "Transfer timed out.",
-    case wait_for_msg(Config, Callback, Req) of
-        timeout when Config#config.polite_ack =:= true ->
-            do_send_msg(Config, Req, Msg, IoList),
-            case Prepared of
-                #prepared{status = terminate, result = Result} ->
-                    terminate(Config, Req, {ok, Result});
-                #prepared{} ->
-                    terminate(Config, Req, ?ERROR(transfer, Code, Text, Req#tftp_msg_req.filename))
-            end;
-        timeout when Retries > 0 ->
-            Retries2 = Retries - 1,
-            do_transfer(Config, Callback, Req, Msg, IoList, LocalAccess, NextBlockNo, Prepared, Retries2);
-        timeout ->
-            Error = #tftp_msg_error{code = Code, text = Text},
-            {Config, Callback, #transfer_res{status = error, prepared = Error}};
-        {Config2, DecodedMsg} ->
-            {Config2, Callback, #transfer_res{status = ok, decoded_msg = DecodedMsg, prepared = Prepared}}
-    end.
-
-send_msg(Config, Req, Msg) ->
-    case catch tftp_lib:encode_msg(Msg) of
-        {'EXIT', Reason} ->
-            Code = undef,
-            Text = "Internal error. Encode failed",
-            Msg2 = #tftp_msg_error{code = Code, text = Text, details = Reason},
-            send_msg(Config, Req, Msg2);
-        IoList ->
-            do_send_msg(Config, Req, Msg, IoList)
-    end.
-
-do_send_msg(#config{udp_socket = Socket, udp_host = RemoteHost, udp_port = RemotePort} = Config, Req, Msg, IoList) ->
-    %% {ok, LocalPort} = inet:port(Socket),
-    %% if
-    %%     LocalPort =/= ?TFTP_DEFAULT_PORT ->
-    %%         ok;
-    %%     true  ->
-    %%         print_debug_info(Config#config{debug_level = all}, Req, send, Msg),
-    %%         error(Config, 
-    %%               "Daemon replies from the default port (~p)\n\t to ~p:~p\n\t¨~p\n",
-    %%               [LocalPort, RemoteHost, RemotePort, Msg])
-    %% end,
-
-    print_debug_info(Config, Req, send, Msg),
-
-    %% case os:getenv("TFTPDUMP") of
-    %%  false     ->
-    %%      ignore;
-    %%  DumpPath  ->
-    %%      trace_udp_send(Req, Msg, IoList, DumpPath)
-    %% end,
-    Res = gen_udp:send(Socket, RemoteHost, RemotePort, IoList),
-    case Res of
-        ok ->
-            ok;
-        {error, einval = Reason} ->
-            error_msg(Config,
-                      "Stacktrace; ~p\n gen_udp:send(~p, ~p, ~p, ~p) -> ~p\n", 
-                      [erlang:get_stacktrace(), Socket, RemoteHost, RemotePort, IoList, {error, Reason}]);
-        {error, Reason} ->
-            {error, Reason} 
-    end.
-
-%% trace_udp_send(#tftp_msg_req{filename = [$/ | RelFile]} = Req, Msg, IoList, DumpPath) ->
-%%     trace_udp_send(Req#tftp_msg_req{filename = RelFile}, Msg, IoList, DumpPath);
-%% trace_udp_send(#tftp_msg_req{filename = RelFile},
-%%             #tftp_msg_data{block_no = BlockNo, data = Data},
-%%             _IoList,
-%%             DumpPath) ->
-%%     File = filename:join([DumpPath, RelFile, "block" ++ string:right(integer_to_list(BlockNo), 5, $0)  ++ ".dump"]),
-%%     if
-%%      (BlockNo rem 1000) =:= 1 -> 
-%%          info_msg(Config, "TFTPDUMP: Data    ~s\n", [File]);
-%%      true ->
-%%          ignore
-%%     end,
-%%     ok = filelib:ensure_dir(File),
-%%     ok = file:write_file(File, Data);
-%% trace_udp_send(#tftp_msg_req{filename = RelFile}, Msg, _IoList, _DumpPath) ->
-%%     info_msg(Config, "TFTPDUMP: No data  ~s -> ~p\n", [RelFile, element(1, Msg)]).
-
-wait_for_msg(Config, Callback, Req) ->
-    receive
-        {udp, Socket, RemoteHost, RemotePort, Bin}
-        when is_binary(Bin), Callback#callback.block_no =:= undefined ->
-            %% Client prepare
-            inet:setopts(Socket, [{active, once}]),
-            Config2 = Config#config{udp_host = RemoteHost,
-                                    udp_port = RemotePort},
-            DecodedMsg = (catch tftp_lib:decode_msg(Bin)),
-            print_debug_info(Config2, Req, recv, DecodedMsg),
-            {Config2, DecodedMsg};
-        {udp, Socket, Host, Port, Bin} when is_binary(Bin),
-                                            Config#config.udp_host =:= Host,
-                                            Config#config.udp_port =:= Port ->
-            inet:setopts(Socket, [{active, once}]),
-            DecodedMsg = (catch tftp_lib:decode_msg(Bin)),
-            print_debug_info(Config, Req, recv, DecodedMsg),
-            {Config, DecodedMsg};
-        {info, Ref, FromPid} when is_pid(FromPid) ->
-            Type =
-                case Req#tftp_msg_req.local_filename =/= undefined of
-                    true  -> client;
-                    false -> server
-                end,
-            Info = internal_info(Config, Type),
-            reply({ok, Info}, Ref, FromPid),
-            wait_for_msg(Config, Callback, Req);
-        {{change_config, Options}, Ref, FromPid} when is_pid(FromPid) ->
-            case catch tftp_lib:parse_config(Options, Config) of
-                {'EXIT', Reason} ->
-                    reply({error, Reason}, Ref, FromPid),
-                    wait_for_msg(Config, Callback, Req);
-                Config2 when is_record(Config2, config) ->
-                    reply(ok, Ref, FromPid),
-                    wait_for_msg(Config2, Callback, Req)
-            end;
-        {system, From, Msg} ->
-            Misc = #sys_misc{module = ?MODULE, function = wait_for_msg, arguments = [Config, Callback, Req]},
-            sys:handle_system_msg(Msg, From, Config#config.parent_pid, ?MODULE, [], Misc);
-        {'EXIT', Pid, _Reason} when Config#config.parent_pid =:= Pid ->
-            Code = undef,
-            Text = "Parent exited.",
-            terminate(Config, Req, ?ERROR(wait_for_msg, Code, Text, Req#tftp_msg_req.filename));
-        Msg when Req#tftp_msg_req.local_filename =/= undefined ->
-            warning_msg(Config, "Client received : ~p", [Msg]),
-            wait_for_msg(Config, Callback, Req);
-        Msg when Req#tftp_msg_req.local_filename =:= undefined ->
-            warning_msg(Config, "Server received : ~p", [Msg]),
-            wait_for_msg(Config, Callback, Req)
-    after Config#config.timeout * 1000 ->
-            print_debug_info(Config, Req, recv, timeout),
-            timeout
-    end.
-
-early_read(Config, Callback, Req, LocalAccess, _NextBlockNo,
-           #prepared{status = Status, next_data = NextData, prev_data = PrevData} = Prepared) ->
-    if
-        Status =/= terminate,
-        LocalAccess =:= read,
-        Callback#callback.block_no =/= undefined,
-        NextData =:= undefined ->
-            case callback(read, Config, Callback, Req) of
-                {undefined, Error} when is_record(Error, tftp_msg_error) ->
-                    {undefined, Error};
-                {Callback2, Prepared2} when is_record(Prepared2, prepared)->
-                    {Callback2, Prepared2#prepared{prev_data = PrevData}}
-            end;
-        true ->
-            {Callback, Prepared}
-    end.
-
-%%-------------------------------------------------------------------
-%% Callback
-%%-------------------------------------------------------------------
-
-callback(Access, Config, Callback, Req) ->
-    {Callback2, Result} =
-        do_callback(Access, Config, Callback, Req),
-    print_debug_info(Config, Req, call, {Callback2, Result}),
-    {Callback2, Result}.
-
-do_callback(read = Fun, Config, Callback, Req) 
-  when is_record(Config, config),
-       is_record(Callback, callback),
-       is_record(Req, tftp_msg_req) ->
-    Args =  [Callback#callback.state],
-    NextBlockNo = Callback#callback.block_no + 1,
-    case catch safe_apply(Callback#callback.module, Fun, Args) of
-        {more, Bin, NewState} when is_binary(Bin) ->
-            Count = Callback#callback.count + size(Bin),
-            Callback2 = Callback#callback{state    = NewState, 
-                                          block_no = NextBlockNo,
-                                          count    = Count},
-            Prepared = #prepared{status    = more,
-                                 result    = undefined,
-                                 block_no  = NextBlockNo,
-                                 next_data = Bin},
-            verify_count(Config, Callback2, Req, Prepared);
-        {last, Bin, Result} when is_binary(Bin) ->
-            Prepared = #prepared{status    = last,
-                                 result    = Result,
-                                 block_no  = NextBlockNo,
-                                 next_data = Bin},
-            {undefined, Prepared};
-        {error, {Code, Text}} ->
-            Error = #tftp_msg_error{code = Code, text = Text},
-            Prepared = #prepared{status = error,
-                                 result = Error},
-            {undefined, Prepared};
-        Illegal ->
-            Code = undef,
-            Text = "Internal error. File handler error.",
-            callback({abort, {Code, Text, Illegal}}, Config, Callback, Req)
-    end;
-do_callback({write = Fun, Bin}, Config, Callback, Req)
-  when is_record(Config, config),
-       is_record(Callback, callback),
-       is_record(Req, tftp_msg_req),
-       is_binary(Bin) ->
-    Args =  [Bin, Callback#callback.state],
-    NextBlockNo = Callback#callback.block_no + 1,
-    case catch safe_apply(Callback#callback.module, Fun, Args) of
-        {more, NewState} ->
-            Count = Callback#callback.count + size(Bin),
-            Callback2 = Callback#callback{state    = NewState, 
-                                          block_no = NextBlockNo,
-                                          count    = Count},
-            Prepared = #prepared{status    = more,
-                                 block_no  = NextBlockNo},          
-            verify_count(Config, Callback2, Req, Prepared);
-        {last, Result} ->
-            Prepared = #prepared{status   = last,
-                                 result   = Result,
-                                 block_no = NextBlockNo},          
-            {undefined, Prepared};
-        {error, {Code, Text}} ->
-            Error = #tftp_msg_error{code = Code, text = Text},
-            Prepared = #prepared{status = error,
-                                 result = Error},
-            {undefined, Prepared};      
-        Illegal ->
-            Code = undef,
-            Text = "Internal error. File handler error.",
-            callback({abort, {Code, Text, Illegal}}, Config, Callback, Req)
-    end;
-do_callback({open, Type}, Config, Callback, Req)
-  when is_record(Config, config),
-       is_record(Callback, callback),
-       is_record(Req, tftp_msg_req) ->
-    {Access, Filename} = local_file_access(Req),
-    {Fun, BlockNo} =
-        case Type of
-            client_prepare -> {prepare, undefined};
-            client_open    -> {open, 0};
-            server_open    -> {open, 0}
-        end,
-    Mod = Callback#callback.module,
-    Args = [Access,
-            Filename,
-            Req#tftp_msg_req.mode,
-            Req#tftp_msg_req.options,
-            Callback#callback.state],
-    PeerInfo = peer_info(Config),
-    fast_ensure_loaded(Mod),
-    Args2 =
-        case erlang:function_exported(Mod, Fun, length(Args)) of
-            true  -> Args;
-            false -> [PeerInfo | Args]
-        end,
-    case catch safe_apply(Mod, Fun, Args2) of
-        {ok, AcceptedOptions, NewState} ->
-            Callback2 = Callback#callback{state    = NewState, 
-                                          block_no = BlockNo, 
-                                          count    = 0}, 
-            {Callback2, {ok, AcceptedOptions}};
-        {error, {Code, Text}} ->
-            {undefined, #tftp_msg_error{code = Code, text = Text}};
-        Illegal ->
-            Code = undef,
-            Text = "Internal error. File handler error.",
-            callback({abort, {Code, Text, Illegal}}, Config, Callback, Req)
-    end;
-do_callback({abort, {Code, Text}}, Config, Callback, Req) ->
-    Error = #tftp_msg_error{code = Code, text = Text},
-    do_callback({abort, Error}, Config, Callback, Req);
-do_callback({abort, {Code, Text, Details}}, Config, Callback, Req) ->
-    Error = #tftp_msg_error{code = Code, text = Text, details = Details},
-    do_callback({abort, Error}, Config, Callback, Req);
-do_callback({abort = Fun, #tftp_msg_error{code = Code, text = Text} = Error}, Config, Callback, Req)
-  when is_record(Config, config),
-       is_record(Callback, callback), 
-       is_record(Req, tftp_msg_req) ->
-    Args =  [Code, Text, Callback#callback.state],
-    catch safe_apply(Callback#callback.module, Fun, Args),
-    {undefined, Error};
-do_callback({abort, Error}, _Config, undefined, _Req) when is_record(Error, tftp_msg_error) ->
-    {undefined, Error}.
-
-peer_info(#config{udp_host = Host, udp_port = Port}) ->
-    if
-        is_tuple(Host), size(Host) =:= 4 ->
-            {inet, tftp_lib:host_to_string(Host), Port};
-        is_tuple(Host), size(Host) =:= 8 ->
-            {inet6, tftp_lib:host_to_string(Host), Port};
-        true ->
-            {undefined, Host, Port}
-    end.
-
-match_callback(Filename, Callbacks) ->
-    if
-        Filename =:= binary ->
-            lookup_callback_mod(tftp_binary, Callbacks);
-        is_binary(Filename) ->
-            lookup_callback_mod(tftp_binary, Callbacks);
-        true ->
-            do_match_callback(Filename, Callbacks)
-    end.
-
-do_match_callback(Filename, [C | Tail]) when is_record(C, callback) ->
-    case catch re:run(Filename, C#callback.internal, [{capture, none}]) of
-        match ->
-            {ok, C};
-        nomatch ->
-            do_match_callback(Filename, Tail);
-        Details ->
-            Code = baduser,
-            Text = "Internal error. File handler not found",
-            {error, #tftp_msg_error{code = Code, text = Text, details = Details}}
-    end;
-do_match_callback(Filename, []) ->
-    Code = baduser,
-    Text = "Internal error. File handler not found",
-    {error, #tftp_msg_error{code = Code, text = Text, details = Filename}}.
-
-lookup_callback_mod(Mod, Callbacks) ->
-    {value, C} = lists:keysearch(Mod, #callback.module, Callbacks),
-    {ok, C}.
-
-verify_count(Config, Callback, Req, Result) ->
-    case Config#config.max_tsize of
-        infinity ->
-            {Callback, Result};
-        Max when Callback#callback.count =< Max ->
-            {Callback, Result};
-        _Max ->
-            Code = enospc,
-            Text = "Too large file.",
-            callback({abort, {Code, Text}}, Config, Callback, Req)
-    end.
-
-%%-------------------------------------------------------------------
-%% Miscellaneous
-%%-------------------------------------------------------------------
-
-internal_info(Config, Type) when is_record(Config, config) ->
-    {ok, ActualPort} = inet:port(Config#config.udp_socket),
-    [
-     {type, Type},
-     {host, tftp_lib:host_to_string(Config#config.udp_host)},
-     {port, Config#config.udp_port},
-     {local_port, ActualPort},
-     {port_policy, Config#config.port_policy},
-     {udp, Config#config.udp_options},
-     {use_tsize, Config#config.use_tsize},
-     {max_tsize, Config#config.max_tsize},
-     {max_conn, Config#config.max_conn},
-     {rejected, Config#config.rejected},
-     {timeout, Config#config.timeout},
-     {polite_ack, Config#config.polite_ack},
-     {debug, Config#config.debug_level},
-     {parent_pid, Config#config.parent_pid}
-    ] ++ Config#config.user_options ++ Config#config.callbacks.
-
-local_file_access(#tftp_msg_req{access = Access, 
-                                local_filename = Local, 
-                                filename = Filename}) ->
-    case Local =:= undefined of
-        true ->
-            %% Server side
-            {Access, Filename};
-        false ->
-            %% Client side
-            case Access of
-                read  -> {write, Local};
-                write -> {read, Local}
-            end
-    end.
-
-pre_verify_options(Config, Req) ->
-    Options = Req#tftp_msg_req.options,
-    case catch verify_reject(Config, Req, Options) of
-        ok ->
-            case verify_integer("tsize", 0, Config#config.max_tsize, Options) of
-                true ->
-                    case verify_integer("blksize", 0, 65464, Options) of
-                        true ->
-                            ok;
-                        false ->
-                            {error, {badopt, "Too large blksize"}}
-                    end;
-                false ->
-                    {error, {badopt, "Too large tsize"}}
-            end;
-        {error, Reason} ->
-            {error, Reason}
-    end.
-    
-post_verify_options(Config, Req, NewOptions, Text) ->
-    OldOptions = Req#tftp_msg_req.options,
-    BadOptions  = 
-        [Key || {Key, _Val} <- NewOptions, 
-                not lists:keymember(Key, 1, OldOptions)],
-    case BadOptions =:= [] of
-        true ->
-            Config2 = Config#config{timeout = lookup_timeout(NewOptions)},
-            Req2 = Req#tftp_msg_req{options = NewOptions},
-            {ok, Config2, Req2};
-        false ->
-            {error, {badopt, Text}}
-    end.
-
-verify_reject(Config, Req, Options) ->
-    Access = Req#tftp_msg_req.access,
-    Rejected = Config#config.rejected,
-    case lists:member(Access, Rejected) of
-        true ->
-            {error, {eacces, atom_to_list(Access) ++ " mode not allowed"}};
-        false ->
-            [throw({error, {badopt, Key ++ " not allowed"}}) ||
-                {Key, _} <- Options, lists:member(Key, Rejected)],
-            ok
-    end.
-
-lookup_timeout(Options) ->
-    case lists:keysearch("timeout", 1, Options) of
-        {value, {_, Val}} ->
-            list_to_integer(Val);
-        false ->
-            3
-    end.
-
-lookup_mode(Options) ->
-    case lists:keysearch("mode", 1, Options) of
-        {value, {_, Val}} ->
-            Val;
-        false ->
-            "octet"
-    end.
-
-verify_integer(Key, Min, Max, Options) ->
-    case lists:keysearch(Key, 1, Options) of
-        {value, {_, Val}} when is_list(Val) ->
-            case catch list_to_integer(Val) of
-                {'EXIT', _} ->
-                    false;
-                Int when Int >= Min, is_integer(Min),
-                         Max =:= infinity ->
-                    true;
-                Int when Int >= Min, is_integer(Min),
-                         Int =< Max, is_integer(Max) ->
-                    true;
-                _ ->
-                    false
-            end;
-        false ->
-            true
-    end.
-
-error_msg(#config{logger = Logger, debug_level = _Level}, F, A) ->
-    safe_apply(Logger, error_msg, [F, A]).
-
-warning_msg(#config{logger = Logger, debug_level = Level}, F, A) ->
-    case Level of
-        none  -> ok;
-        error -> ok;
-        _     -> safe_apply(Logger, warning_msg, [F, A])
-    end.
-
-info_msg(#config{logger = Logger}, F, A) ->
-    safe_apply(Logger, info_msg, [F, A]).
-
-safe_apply(Mod, Fun, Args) ->
-    fast_ensure_loaded(Mod),
-    apply(Mod, Fun, Args).
-
-fast_ensure_loaded(Mod) ->
-    case erlang:function_exported(Mod, module_info, 0) of
-        true  ->
-            ok;
-        false ->
-            Res = code:load_file(Mod),
-            %% io:format("tftp: code:load_file(~p) -> ~p\n", [Mod, Res]), %% XXX
-            Res
-    end.
-    
-print_debug_info(#config{debug_level = Level} = Config, Who, Where, Data) ->
-    if
-        Level =:= none ->
-            ok;
-        is_record(Data, error) ->
-            do_print_debug_info(Config, Who, Where, Data);
-        Level =:= warning ->
-            ok;
-        Level =:= error ->
-            ok; 
-        Level =:= all ->
-            do_print_debug_info(Config, Who, Where, Data);
-        Where =:= open ->
-            do_print_debug_info(Config, Who, Where, Data);
-        Where =:= close ->
-            do_print_debug_info(Config, Who, Where, Data);
-        Level =:= brief ->
-            ok; 
-        Where =/= recv, Where =/= send ->
-            ok;
-        is_record(Data, tftp_msg_data), Level =:= normal ->
-            ok;  
-        is_record(Data, tftp_msg_ack), Level =:= normal ->
-            ok;
-        true ->
-            do_print_debug_info(Config, Who, Where, Data)
-    end.
-
-do_print_debug_info(Config, Who, Where, #tftp_msg_data{data = Bin} = Msg) when is_binary(Bin) ->
-    Msg2 = Msg#tftp_msg_data{data = {bytes, size(Bin)}},
-    do_print_debug_info(Config, Who, Where, Msg2);
-do_print_debug_info(Config, Who, Where, #tftp_msg_req{local_filename = Filename} = Msg) when is_binary(Filename) ->
-    Msg2 = Msg#tftp_msg_req{local_filename = binary},
-    do_print_debug_info(Config, Who, Where, Msg2);
-do_print_debug_info(Config, Who, Where, Data) ->
-    Local = 
-        case catch inet:port(Config#config.udp_socket) of
-            {'EXIT', _Reason} ->
-                0;
-            {ok, Port} ->
-                Port
-        end,
-    %% Remote = Config#config.udp_port,
-    PeerInfo = lists:flatten(io_lib:format("~p", [peer_info(Config)])),
-    Side = 
-        if
-            is_record(Who, tftp_msg_req),
-            Who#tftp_msg_req.local_filename =/= undefined ->
-                client;
-            is_record(Who, tftp_msg_req),
-            Who#tftp_msg_req.local_filename =:= undefined ->
-                server;
-            is_atom(Who) ->
-                Who
-        end,
-    case {Where, Data} of
-        {_, #error{where = Where, code = Code, text = Text, filename = Filename}} -> 
-            do_format(Config, Side, Local, "error ~s ->\n\t~p ~p\n\t~p ~p: ~s\n",
-                      [PeerInfo, self(), Filename, Where, Code, Text]);
-        {open, #tftp_msg_req{filename = Filename}} ->
-            do_format(Config, Side, Local, "open  ~s ->\n\t~p ~p\n",
-                      [PeerInfo, self(), Filename]);
-        {close, #tftp_msg_req{filename = Filename}} ->
-            do_format(Config, Side, Local, "close ~s ->\n\t~p ~p\n",
-                      [PeerInfo, self(), Filename]);
-        {recv, _} ->
-            do_format(Config, Side, Local, "recv  ~s <-\n\t~p\n",
-                      [PeerInfo, Data]);
-        {send, _} ->
-            do_format(Config, Side, Local, "send  ~s ->\n\t~p\n",
-                      [PeerInfo, Data]);
-        {match, _} when is_record(Data, callback) ->
-            Mod = Data#callback.module,
-            State = Data#callback.state,
-            do_format(Config, Side, Local, "match ~s ~p =>\n\t~p\n",
-                      [PeerInfo, Mod, State]);
-        {call, _} ->
-            case Data of
-                {Callback, _Result} when is_record(Callback, callback) ->
-                    Mod   = Callback#callback.module,
-                    State = Callback#callback.state,
-                    do_format(Config, Side, Local, "call ~s ~p =>\n\t~p\n",
-                              [PeerInfo, Mod, State]);
-                {undefined, Result}  ->
-                    do_format(Config, Side, Local, "call ~s result =>\n\t~p\n",
-                              [PeerInfo, Result])
-            end
-    end.
-
-do_format(Config, Side, Local, Format, Args) ->
-    info_msg(Config, "~p(~p): " ++ Format, [Side, Local | Args]).
-
-%%-------------------------------------------------------------------
-%% System upgrade
-%%-------------------------------------------------------------------
-
-system_continue(_Parent, _Debug, #sys_misc{module = Mod, function = Fun, arguments = Args}) ->
-    apply(Mod, Fun, Args);
-system_continue(Parent, Debug, {Fun, Args}) ->
-    %% Handle upgrade from old releases. Please, remove this clause in next release.
-    system_continue(Parent, Debug, #sys_misc{module = ?MODULE, function = Fun, arguments = Args}).
-
--spec system_terminate(_, _, _, #sys_misc{} | {_, _}) -> no_return().
-
-system_terminate(Reason, _Parent, _Debug, #sys_misc{}) ->
-    exit(Reason);
-system_terminate(Reason, Parent, Debug, {Fun, Args}) ->
-    %% Handle upgrade from old releases. Please, remove this clause in next release.
-    system_terminate(Reason, Parent, Debug, #sys_misc{module = ?MODULE, function = Fun, arguments = Args}).
-
-system_code_change({Fun, Args}, _Module, _OldVsn, _Extra) ->
-    {ok, {Fun, Args}}.