%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2018. 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%
%%

%% A primary loader, provides two different methods to fetch a file:
%% efile and inet. The efile method is simple communication with a
%% port program.
%%
%% The distribution loading was removed and replaced with
%% inet loading
%%
%% The start_it/4 function initializes a record with callback 
%% functions used to handle the interface functions.
%%

-module(erl_prim_loader).

%% If the macro DEBUG is defined during compilation, 
%% debug printouts are done through erlang:display/1.
%% Activate this feature by starting the compiler 
%% with> erlc -DDEBUG ... 
%% or by> setenv ERL_COMPILER_FLAGS DEBUG 
%% before running make (in the OTP make system)
%% (the example is for tcsh)

-include("inet_boot.hrl").

%% Public
-export([start/0, set_path/1, get_path/0, get_file/1,
         list_dir/1, read_file_info/1, read_link_info/1, get_cwd/0, get_cwd/1]).

%% Used by erl_boot_server
-export([prim_init/0, prim_get_file/2, prim_list_dir/2,
         prim_read_file_info/3, prim_get_cwd/2]).

%% Used by escript and code
-export([set_primary_archive/4]).

%% Used by test suites
-export([purge_archive_cache/0]).

%% Used by init and the code server.
-export([get_modules/2,get_modules/3, is_basename/1]).

-include_lib("kernel/include/file.hrl").

-type host() :: atom().

-record(prim_state, {debug :: boolean(),
		     primary_archive}).
-type prim_state() :: #prim_state{}.

-record(state, 
        {loader            :: 'efile' | 'inet',
         hosts = []        :: [host()], % hosts list (to boot from)
         data              :: 'noport' | port(), % data port etc
         timeout           :: timeout(),	 % idle timeout
         prim_state        :: prim_state()}).    % state for efile code loader

-define(EFILE_IDLE_TIMEOUT, (6*60*1000)).	%purge archives
-define(INET_IDLE_TIMEOUT, (60*1000)). 		%tear down connection timeout

%% Defines for inet as prim_loader
-define(INET_FAMILY, inet).
-define(INET_ADDRESS, {0,0,0,0}).

-ifdef(DEBUG).
-define(dbg(Tag, Data), erlang:display({Tag,Data})).
-else.
-define(dbg(Tag, Data), true).
-endif.

-define(SAFE2(Expr, State), 
        fun() ->
                case catch Expr of
                    {'EXIT',XXXReason} -> {{error,XXXReason}, State};
                    XXXRes -> XXXRes
                end
        end()).

debug(#prim_state{debug = Deb}, Term) ->
    case Deb of
        false -> ok;
        true  -> erlang:display(Term)
    end.

%%% --------------------------------------------------------
%%% Interface Functions. 
%%% --------------------------------------------------------

-spec start() ->
	    {'ok', Pid} | {'error', What} when
      Pid :: pid(),
      What :: term().
start() ->
    Self = self(),
    Pid = spawn_link(fun() -> start_it(Self) end),
    receive
        {Pid,ok} ->
            {ok,Pid};
        {'EXIT',Pid,Reason} ->
            {error,Reason}
    end.

start_it(Parent) ->
    process_flag(trap_exit, true),
    register(erl_prim_loader, self()),
    Loader = case init:get_argument(loader) of
		 {ok,[[Loader0]]} ->
		     Loader0;
		 error ->
		     "efile"
	     end,
    case Loader of
	"efile" -> start_efile(Parent);
	"inet" -> start_inet(Parent)
    end.

%% Hosts must be a list of form ['1.2.3.4' ...]
start_inet(Parent) ->
    Hosts = case init:get_argument(hosts) of
		{ok,[Hosts0]} -> Hosts0;
		_ -> []
	    end,
    AL = ipv4_list(Hosts),
    ?dbg(addresses, AL),
    {ok,Tcp} = find_master(AL),
    init_ack(Parent),
    PS = prim_init(),
    State = #state {loader = inet,
                    hosts = AL,
                    data = Tcp,
                    timeout = ?INET_IDLE_TIMEOUT,
                    prim_state = PS},
    loop(State, Parent, []).

start_efile(Parent) ->
    %% Check that we started in a valid directory.
    case prim_file:get_cwd() of
	{error, _} ->
	    %% At this point in the startup, we have no error_logger at all.
	    Report = "Invalid current directory or invalid filename "
		"mode: loader cannot read current directory\n",
	    erlang:display(Report),
	    exit({error, invalid_current_directory});
	_ ->
	    init_ack(Parent)
    end,
    PS = prim_init(),
    State = #state {loader = efile,
                    data = noport,
                    timeout = ?EFILE_IDLE_TIMEOUT,
                    prim_state = PS},
    loop(State, Parent, []).

init_ack(Pid) ->
    Pid ! {self(),ok},
    ok.

-spec set_path(Path) -> 'ok' when
      Path :: [Dir :: string()].
set_path(Paths) when is_list(Paths) ->
    request({set_path,Paths}).

-spec get_path() -> {'ok', Path} when
      Path :: [Dir :: string()].
get_path() ->
    request({get_path,[]}).

-spec get_file(Filename) -> {'ok', Bin, FullName} | 'error' when
      Filename :: atom() | string(),
      Bin :: binary(),
      FullName :: string().
get_file(File) when is_atom(File) ->
    get_file(atom_to_list(File));
get_file(File) ->
    check_file_result(get_file, File, request({get_file,File})).

-spec list_dir(Dir) -> {'ok', Filenames} | 'error' when
      Dir :: string(),
      Filenames :: [Filename :: string()].
list_dir(Dir) ->
    check_file_result(list_dir, Dir, request({list_dir,Dir})).

-spec read_file_info(Filename) -> {'ok', FileInfo} | 'error' when
      Filename :: string(),
      FileInfo :: file:file_info().
read_file_info(File) ->
    check_file_result(read_file_info, File, request({read_file_info,File})).

-spec read_link_info(Filename) -> {'ok', FileInfo} | 'error' when
      Filename :: string(),
      FileInfo :: file:file_info().
read_link_info(File) ->
    check_file_result(read_link_info, File, request({read_link_info,File})).

-spec get_cwd() -> {'ok', string()} | 'error'.
get_cwd() ->
    check_file_result(get_cwd, [], request({get_cwd,[]})).

-spec get_cwd(string()) -> {'ok', string()} | 'error'.
get_cwd(Drive) ->
    check_file_result(get_cwd, Drive, request({get_cwd,[Drive]})).

-spec set_primary_archive(File :: string() | 'undefined', 
			  ArchiveBin :: binary() | 'undefined',
			  FileInfo :: #file_info{} | 'undefined',
			  ParserFun :: fun())
			 -> {ok, [string()]} | {error,_}.

set_primary_archive(undefined, undefined, undefined, ParserFun) ->
    request({set_primary_archive, undefined, undefined, undefined, ParserFun});
set_primary_archive(File, ArchiveBin, FileInfo, ParserFun)
  when is_list(File), is_binary(ArchiveBin), is_record(FileInfo, file_info) ->
    request({set_primary_archive, File, ArchiveBin, FileInfo, ParserFun}).

%% NOTE: Does not close the primary archive. Only closes all
%% open zip files kept in the cache. Should be called before an archive
%% file is to be removed (for example in the test suites).

-spec purge_archive_cache() -> 'ok' | {'error', _}.
purge_archive_cache() ->
    request(purge_archive_cache).

-spec get_modules([module()],
		  fun((atom(), string(), binary()) ->
			     {'ok',any()} | {'error',any()})) ->
			 {'ok',{[any()],[any()]}}.

get_modules(Modules, Fun) ->
    request({get_modules,{Modules,Fun}}).

-spec get_modules([module()],
		  fun((atom(), string(), binary()) ->
			     {'ok',any()} | {'error',any()}),
		  [string()]) ->
			 {'ok',{[any()],[any()]}}.

get_modules(Modules, Fun, Path) ->
    request({get_modules,{Modules,Fun,Path}}).

request(Req) ->
    Loader = whereis(erl_prim_loader),
    Loader ! {self(),Req},
    receive
        {Loader,Res} ->
            Res;
        {'EXIT',Loader,_What} ->
            error
    end.

check_file_result(_, _, {error,enoent}) ->
    error;
check_file_result(_, _, {error,enotdir}) ->
    error;
check_file_result(_, _, {error,einval}) ->
    error;
check_file_result(Func, Target, {error,Reason}) ->   
    case (catch atom_to_list(Reason)) of
        {'EXIT',_} ->                           % exit trapped
            error;
        Errno ->                                % errno
            Process = case process_info(self(), registered_name) of
                          {registered_name,R} -> 
                              "Process: " ++ atom_to_list(R) ++ ".";
                          _ -> 
                              ""
                      end,
            TargetStr =
                if is_atom(Target) -> atom_to_list(Target);
                   is_list(Target) -> Target;
                   true -> []
                end,
            Report = 
                case TargetStr of
                    [] ->
                        "File operation error: " ++ Errno ++ ". " ++
                        "Function: " ++ atom_to_list(Func) ++ ". " ++ Process;
                    _ ->
                        "File operation error: " ++ Errno ++ ". " ++
                        "Target: " ++ TargetStr ++ ". " ++
                        "Function: " ++ atom_to_list(Func) ++ ". " ++ Process
                end,
            %% this is equal to calling error_logger:error_report/1 which
            %% we don't want to do from code_server during system boot
            logger ! {log,error,#{label=>{?MODULE,file_error},report=>Report},
                      #{pid=>self(),
                        gl=>group_leader(),
                        time=>erlang:monotonic_time(microsecond),
                        error_logger=>#{tag=>error_report,
                                        type=>std_error}}},
            error
    end;
check_file_result(_, _, Other) ->
    Other.

%%% --------------------------------------------------------
%%% The main loop.
%%% --------------------------------------------------------

loop(St0, Parent, Paths) ->
    receive
	{Pid,{set_path,NewPaths}} when is_pid(Pid) ->
	    Pid ! {self(),ok},
	    loop(St0, Parent, to_strs(NewPaths));
        {Pid,Req} when is_pid(Pid) ->
	    case handle_request(Req, Paths, St0) of
		ignore ->
		    ok;
		{Resp,#state{}=St1} ->
		    Pid ! {self(),Resp},
                    loop(St1, Parent, Paths);
		{_,State2,_} ->
                    exit({bad_state,Req,State2})
            end;
        {'EXIT',Parent,W} ->
            _ = handle_stop(St0),
            exit(W);
        {'EXIT',P,W} ->
            St1 = handle_exit(St0, P, W),
            loop(St1, Parent, Paths);
        _Message ->
            loop(St0, Parent, Paths)
    after St0#state.timeout ->
            St1 = handle_timeout(St0, Parent),
            loop(St1, Parent, Paths)
    end.

handle_request(Req, Paths, St0) ->
    case Req of
	{get_path,_} ->
	    {{ok,Paths},St0};
	{get_file,File} ->
	    handle_get_file(St0, Paths, File);
	{get_modules,{Modules,Fun}} ->
	    handle_get_modules(St0, Modules, Fun, Paths);
	{get_modules,{Modules,Fun,ModPaths}} ->
	    handle_get_modules(St0, Modules, Fun, ModPaths);
	{list_dir,Dir} ->
	    handle_list_dir(St0, Dir);
	{read_file_info,File} ->
	    handle_read_file_info(St0, File);
	{read_link_info,File} ->
	    handle_read_link_info(St0, File);
	{get_cwd,[]} ->
	    handle_get_cwd(St0, []);
	{get_cwd,[_]=Args} ->
	    handle_get_cwd(St0, Args);
	{set_primary_archive,File,ArchiveBin,FileInfo,ParserFun} ->
	    handle_set_primary_archive(St0, File, ArchiveBin,
				       FileInfo, ParserFun);
	purge_archive_cache ->
	    handle_purge_archive_cache(St0);
	_ ->
	    ignore
    end.

handle_get_file(State = #state{loader = efile}, Paths, File) ->
    ?SAFE2(efile_get_file_from_port(State, File, Paths), State);
handle_get_file(State = #state{loader = inet}, Paths, File) ->
    ?SAFE2(inet_get_file_from_port(State, File, Paths), State).

handle_set_primary_archive(State= #state{loader = efile}, File, ArchiveBin, FileInfo, ParserFun) ->
    ?SAFE2(efile_set_primary_archive(State, File, ArchiveBin, FileInfo, ParserFun), State).

handle_purge_archive_cache(#state{loader = efile}=State) ->
    prim_purge_cache(),
    {ok,State}.

handle_list_dir(State = #state{loader = efile}, Dir) ->
    ?SAFE2(efile_list_dir(State, Dir), State);
handle_list_dir(State = #state{loader = inet}, Dir) ->
    ?SAFE2(inet_list_dir(State, Dir), State).

handle_read_file_info(State = #state{loader = efile}, File) ->
    ?SAFE2(efile_read_file_info(State, File, true), State);
handle_read_file_info(State = #state{loader = inet}, File) ->
    ?SAFE2(inet_read_file_info(State, File), State).

handle_read_link_info(State = #state{loader = efile}, File) ->
    ?SAFE2(efile_read_file_info(State, File, false), State);
handle_read_link_info(State = #state{loader = inet}, File) ->
    ?SAFE2(inet_read_link_info(State, File), State).

handle_get_cwd(State = #state{loader = efile}, Drive) ->
    ?SAFE2(efile_get_cwd(State, Drive), State);
handle_get_cwd(State = #state{loader = inet}, Drive) ->
    ?SAFE2(inet_get_cwd(State, Drive), State).
    
handle_stop(State = #state{loader = efile}) ->
    State;
handle_stop(State = #state{loader = inet}) ->
    inet_stop_port(State).

handle_exit(State = #state{loader = efile}, _Who, _Reason) ->
    State;
handle_exit(State = #state{loader = inet}, Who, Reason) ->
    inet_exit_port(State, Who, Reason).

handle_timeout(State = #state{loader = efile}, Parent) ->
    efile_timeout_handler(State, Parent);
handle_timeout(State = #state{loader = inet}, Parent) ->
    inet_timeout_handler(State, Parent).

%%% --------------------------------------------------------
%%% Functions which handle efile as prim_loader (default).
%%% --------------------------------------------------------


%% -> {{ok,BinFile,File},State} | {{error,Reason},State}
efile_get_file_from_port(State, File, Paths) ->
    case is_basename(File) of
        false ->                        % get absolute file name.
            efile_get_file_from_port2(State, File);
        true when Paths =:= [] ->       % get plain file name.
            efile_get_file_from_port2(State, File);
        true ->                         % use paths.
            efile_get_file_from_port3(State, File, Paths)
    end.

efile_get_file_from_port2(#state{prim_state = PS} = State, File) ->
    {Res, PS2} = prim_get_file(PS, File),
    case Res of
        {error,port_died} ->
            exit('prim_load port died');
        {error,Reason} ->
            {{error,Reason},State#state{prim_state = PS2}};
        {ok,BinFile} ->
            {{ok,BinFile,File},State#state{prim_state = PS2}}
    end.

efile_get_file_from_port3(State, File, [P | Paths]) ->
    case efile_get_file_from_port2(State, join(P, File)) of
        {{error,Reason},State1} when Reason =/= emfile ->
            case Paths of
                [] ->                           % return last error
                    {{error,Reason},State1};
                _ ->                            % try more paths
                    efile_get_file_from_port3(State1, File, Paths)
            end;
        Result ->
            Result
    end;
efile_get_file_from_port3(State, _File, []) ->
    {{error,enoent},State}.

efile_set_primary_archive(#state{prim_state = PS} = State, File,
			  ArchiveBin, FileInfo, ParserFun) ->
    {Res, PS2} = prim_set_primary_archive(PS, File, ArchiveBin,
					  FileInfo, ParserFun),
    {Res,State#state{prim_state = PS2}}.

efile_list_dir(#state{prim_state = PS} = State, Dir) ->
    {Res, PS2} = prim_list_dir(PS, Dir),
    {Res, State#state{prim_state = PS2}}.

efile_read_file_info(#state{prim_state = PS} = State, File, FollowLinks) ->
    {Res, PS2} = prim_read_file_info(PS, File, FollowLinks),
    {Res, State#state{prim_state = PS2}}.

efile_get_cwd(#state{prim_state = PS} = State, Drive) ->
    {Res, PS2} = prim_get_cwd(PS, Drive),
    {Res, State#state{prim_state = PS2}}.

efile_timeout_handler(State, _Parent) ->
    prim_purge_cache(),
    State.

%%% --------------------------------------------------------
%%% Read and process severals modules in parallel.
%%% --------------------------------------------------------

handle_get_modules(#state{loader=efile}=St, Ms, Process, Paths) ->
    Primary = (St#state.prim_state)#prim_state.primary_archive,
    Res = case efile_any_archives(Paths, Primary) of
	      false ->
		  efile_get_mods_par(Ms, Process, Paths);
	      true ->
		  Get = fun efile_get_file_from_port/3,
		  gm_get_mods(St, Get, Ms, Process, Paths)
	  end,
    {Res,St};
handle_get_modules(#state{loader=inet}=St, Ms, Process, Paths) ->
    Get = fun inet_get_file_from_port/3,
    {gm_get_mods(St, Get, Ms, Process, Paths),St}.

efile_get_mods_par(Ms, Process, Paths) ->
    Self = self(),
    Ref = make_ref(),
    GmSpawn = fun() ->
		      efile_gm_spawn({Self,Ref}, Ms, Process, Paths)
	      end,
    _ = spawn_link(GmSpawn),
    N = length(Ms),
    efile_gm_recv(N, Ref, [], []).

efile_any_archives([H|T], Primary) ->
    case name_split(Primary, H) of
	{file,_} -> efile_any_archives(T, Primary);
	{archive,_,_} -> true
    end;
efile_any_archives([], _) ->
    false.

efile_gm_recv(0, _Ref, Succ, Fail) ->
    {ok,{Succ,Fail}};
efile_gm_recv(N, Ref, Succ, Fail) ->
    receive
	{Ref,Mod,{ok,Res}} ->
	    efile_gm_recv(N-1, Ref, [{Mod,Res}|Succ], Fail);
	{Ref,Mod,{error,Res}} ->
	    efile_gm_recv(N-1, Ref, Succ, [{Mod,Res}|Fail])
    end.

efile_gm_spawn(ParentRef, Ms, Process, Paths) ->
    efile_gm_spawn_1(0, Ms, ParentRef, Process, Paths).

efile_gm_spawn_1(N, Ms, ParentRef, Process, Paths) when N >= 32 ->
    receive
	{'DOWN',_,process,_,_} ->
	    efile_gm_spawn_1(N-1, Ms, ParentRef, Process, Paths)
    end;
efile_gm_spawn_1(N, [M|Ms], ParentRef, Process, Paths) ->
    Get = fun() -> efile_gm_get(Paths, M, ParentRef, Process) end,
    _ = spawn_monitor(Get),
    efile_gm_spawn_1(N+1, Ms, ParentRef, Process, Paths);
efile_gm_spawn_1(_, [], _, _, _) ->
    ok.

efile_gm_get(Paths, Mod, ParentRef, Process) ->
    File = atom_to_list(Mod) ++ init:objfile_extension(),
    efile_gm_get_1(Paths, File, Mod, ParentRef, Process).

efile_gm_get_1([P|Ps], File0, Mod, {Parent,Ref}=PR, Process) ->
    File = join(P, File0),
    try prim_file:read_file(File) of
	{ok,Bin} ->
	    Res = gm_process(Mod, File, Bin, Process),
	    Parent ! {Ref,Mod,Res};
	Error ->
	    _ = check_file_result(get_modules, File, Error),
	    efile_gm_get_1(Ps, File0, Mod, PR, Process)
    catch
	_:Reason ->
	    Res = {error,{crash,Reason}},
	    Parent ! {Ref,Mod,Res}
    end;
efile_gm_get_1([], _, Mod, {Parent,Ref}, _Process) ->
    Parent ! {Ref,Mod,{error,enoent}}.

gm_get_mods(St, Get, Ms, Process, Paths) ->
    gm_get_mods(St, Get, Ms, Process, Paths, [], []).

gm_get_mods(St, Get, [M|Ms], Process, Paths, Succ, Fail) ->
    File = atom_to_list(M) ++ init:objfile_extension(),
    case gm_arch_get(St, Get, M, File, Paths, Process) of
	{ok,Res} ->
	    gm_get_mods(St, Get, Ms, Process, Paths,
			[{M,Res}|Succ], Fail);
	{error,Res} ->
	    gm_get_mods(St, Get, Ms, Process, Paths,
			Succ, [{M,Res}|Fail])
    end;
gm_get_mods(_St, _Get, [], _, _, Succ, Fail) ->
    {ok,{Succ,Fail}}.

gm_arch_get(St, Get, Mod, File, Paths, Process) ->
    case Get(St, File, Paths) of
	{{error,_}=E,_} ->
	    E;
	{{ok,Bin,Full},_} ->
	    gm_process(Mod, Full, Bin, Process)
    end.

gm_process(Mod, File, Bin, Process) ->
    try Process(Mod, File, Bin) of
	{ok,_}=Res -> Res;
	{error,_}=Res -> Res;
	Other -> {error,{bad_return,Other}}
    catch
	_:Error ->
	    {error,{crash,Error}}
    end.


%%% --------------------------------------------------------
%%% Functions which handle inet prim_loader
%%% --------------------------------------------------------

%%
%% Connect to a boot master
%% return {ok, Socket}  TCP
%% AL is a list of boot servers (including broadcast addresses)
%%
find_master(AL) ->
    find_master(AL, ?EBOOT_RETRY, ?EBOOT_REQUEST_DELAY, ?EBOOT_SHORT_RETRY_SLEEP, 
               ?EBOOT_UNSUCCESSFUL_TRIES, ?EBOOT_LONG_RETRY_SLEEP).

find_master(AL, Retry, ReqDelay, SReSleep, Tries, LReSleep) ->
    {ok,U} = ll_udp_open(0),
    find_master(U, Retry, AL, ReqDelay, SReSleep, [], Tries, LReSleep).

%%
%% Master connect loop
%%
find_master(U, Retry, AddrL, ReqDelay, SReSleep, Ignore, Tries, LReSleep) ->
    case find_loop(U, Retry, AddrL, ReqDelay, SReSleep, Ignore, 
                   Tries, LReSleep) of
        [] ->   
            find_master(U, Retry, AddrL, ReqDelay, SReSleep, Ignore, 
                        Tries, LReSleep);
        Servers ->
            ?dbg(servers, Servers),
            case connect_master(Servers) of
                {ok, Socket} -> 
                    ll_close(U),
                    {ok, Socket};
                _Error ->
                    find_master(U, Retry, AddrL, ReqDelay, SReSleep, 
                                Servers ++ Ignore, Tries, LReSleep)
            end
    end.

connect_master([{_Prio,IP,Port} | Servers]) ->
    case ll_tcp_connect(0, IP, Port) of
        {ok, S} -> {ok, S};
        _Error -> connect_master(Servers)
    end;
connect_master([]) ->
    {error, ebusy}.

%%
%% Always return a list of boot servers or hang.
%%
find_loop(U, Retry, AL, ReqDelay, SReSleep, Ignore, Tries, LReSleep) ->
    case find_loop(U, Retry, AL, ReqDelay, []) of
        [] ->                                   % no response from any server
            erlang:display({erl_prim_loader,'no server found'}), % lifesign
            Tries1 =
		if Tries > 0 ->
			sleep(SReSleep),
			Tries - 1;
		   true ->
			sleep(LReSleep),
			0
		end,
            find_loop(U, Retry, AL, ReqDelay, SReSleep, Ignore, Tries1, LReSleep);
        Servers ->
            keysort(1, Servers -- Ignore)
    end.

%% broadcast or send
find_loop(_U, 0, _AL, _Delay, Acc) ->
    Acc;
find_loop(U, Retry, AL, Delay, Acc) ->
    send_all(U, AL, [?EBOOT_REQUEST, erlang:system_info(version)]),
    find_collect(U, Retry-1, AL, Delay, Acc).

find_collect(U,Retry,AL,Delay,Acc) ->
    receive
        {udp, U, IP, _Port, [$E,$B,$O,$O,$T,$R,Priority,T1,T0 | _Version]} ->
            Elem = {Priority,IP,T1*256+T0},
            ?dbg(got, Elem),
            case member(Elem, Acc) of
                false  -> find_collect(U, Retry, AL, Delay, [Elem | Acc]);
                true -> find_collect(U, Retry, AL, Delay, Acc)
            end;
        _Garbage ->
            ?dbg(collect_garbage, _Garbage),
            find_collect(U, Retry, AL, Delay, Acc)
    after Delay ->
            ?dbg(collected, Acc),
            case keymember(0, 1, Acc) of  %% got high priority server?
                true -> Acc;
                false -> find_loop(U, Retry, AL, Delay, Acc)
            end
    end.

    
sleep(Time) ->
    receive after Time -> ok end.

inet_exit_port(State, Port, _Reason) when State#state.data =:= Port ->
    State#state{data = noport, timeout = infinity};
inet_exit_port(State, _, _) ->
    State.


inet_timeout_handler(State, _Parent) ->
    Tcp = State#state.data,
    if is_port(Tcp) -> ll_close(Tcp);
       true -> ok
    end,
    State#state{timeout = infinity, data = noport}.

%% -> {{ok,BinFile,Tag},State} | {{error,Reason},State}
inet_get_file_from_port(State, File, Paths) ->
    case is_basename(File) of
        false ->                        % get absolute file name.
            inet_send_and_rcv({get,File}, File, State);
        true when Paths =:= [] ->       % get plain file name.
            inet_send_and_rcv({get,File}, File, State);
        true ->                         % use paths.
            inet_get_file_from_port1(File, Paths, State)
    end.

inet_get_file_from_port1(File, [P | Paths], State) ->
    File1 = join(P, File),
    case inet_send_and_rcv({get,File1}, File1, State) of
        {{error,Reason},State1} ->
            case Paths of
                [] ->                           % return last error
                    {{error,Reason},State1};
                _ ->                            % try more paths            
                    inet_get_file_from_port1(File, Paths, State1)
            end;
        Result -> Result
    end;
inet_get_file_from_port1(_File, [], State) ->
    {{error,file_not_found},State}.

inet_send_and_rcv(Msg, Tag, State) when State#state.data =:= noport ->
    {ok,Tcp} = find_master(State#state.hosts),     %% reconnect
    inet_send_and_rcv(Msg, Tag, State#state{data = Tcp,
					    timeout = ?INET_IDLE_TIMEOUT});
inet_send_and_rcv(Msg, Tag, #state{data = Tcp, timeout = Timeout} = State) ->
    prim_inet:send(Tcp, term_to_binary(Msg)),
    receive
        {tcp,Tcp,BinMsg} ->
            case catch binary_to_term(BinMsg) of
                {get,{ok,BinFile}} ->
                    {{ok,BinFile,Tag},State};
                {_Cmd,Res={ok,_}} ->
                    {Res,State};
                {_Cmd,{error,Error}} ->
                    {{error,Error},State};
                {error,Error} ->
                    {{error,Error},State};
                {'EXIT',Error} ->
                    {{error,Error},State}
            end;
        {tcp_closed,Tcp} ->
            %% Ok we must reconnect
            inet_send_and_rcv(Msg, Tag, State#state{data = noport});
        {tcp_error,Tcp,_Reason} ->
            %% Ok we must reconnect
            inet_send_and_rcv(Msg, Tag, inet_stop_port(State));
        {'EXIT', Tcp, _} -> 
            %% Ok we must reconnect
            inet_send_and_rcv(Msg, Tag, State#state{data = noport})
    after Timeout ->
            %% Ok we must reconnect
            inet_send_and_rcv(Msg, Tag, inet_stop_port(State))
    end.

%% -> {{ok,List},State} | {{error,Reason},State}
inet_list_dir(State, Dir) ->
    inet_send_and_rcv({list_dir,Dir}, list_dir, State).

%% -> {{ok,Info},State} | {{error,Reason},State}
inet_read_file_info(State, File) ->
    inet_send_and_rcv({read_file_info,File}, read_file_info, State).

%% -> {{ok,Info},State} | {{error,Reason},State}
inet_read_link_info(State, File) ->
    inet_send_and_rcv({read_link_info,File}, read_link_info, State).

%% -> {{ok,Cwd},State} | {{error,Reason},State}
inet_get_cwd(State, []) ->
    inet_send_and_rcv(get_cwd, get_cwd, State);
inet_get_cwd(State, [Drive]) ->
    inet_send_and_rcv({get_cwd,Drive}, get_cwd, State).

inet_stop_port(#state{data=Tcp}=State) ->
    prim_inet:close(Tcp),
    State#state{data=noport}.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% Direct inet_drv access
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

tcp_options() ->
    [{mode,binary}, {packet,4}, {active, true}, {deliver,term}].

tcp_timeout() -> 
    15000.

%% options for udp  [list, {broadcast, true}, {active,true}]
udp_options() ->
    [{mode,list}, {active, true}, {deliver,term}, {broadcast,true}].
%%
%% INET version IPv4 addresses
%%
ll_tcp_connect(LocalPort, IP, RemotePort) ->
    case ll_open_set_bind(tcp, ?INET_FAMILY, stream, tcp_options(),
                          ?INET_ADDRESS, LocalPort) of
        {ok,S} ->
            case prim_inet:connect(S, IP, RemotePort, tcp_timeout()) of
                ok -> {ok, S};
                Error -> port_error(S, Error)
            end;
        Error -> Error
    end.

%%
%% Open and initialize an udp port for broadcast
%%
ll_udp_open(P) ->
    ll_open_set_bind(udp, ?INET_FAMILY, dgram, udp_options(), ?INET_ADDRESS, P).


ll_open_set_bind(Protocol, Family, Type, SOpts, IP, Port) ->
    case prim_inet:open(Protocol, Family, Type) of
        {ok, S} ->
            case prim_inet:setopts(S, SOpts) of
                ok ->
                    case prim_inet:bind(S, IP, Port) of
                        {ok,_} ->
                            {ok, S};
                        Error -> port_error(S, Error)
                    end;
                Error -> port_error(S, Error)
            end;
        Error -> Error
    end.
                    

ll_close(S) ->
    unlink(S),
    exit(S, kill).

port_error(S, Error) ->
    unlink(S),
    prim_inet:close(S),
    Error.
    
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

-spec prim_init() -> prim_state().
prim_init() ->
    Deb =
        case init:get_argument(loader_debug) of
            {ok, _} -> true;
            error -> false
        end,
    cache_new(#prim_state{debug = Deb}).

prim_purge_cache() ->
    do_prim_purge_cache(get()).

do_prim_purge_cache([{Key,Val}|T]) ->
    case Val of
	{Cache,_FI} ->
	    catch clear_cache(Key, Cache);
	_ ->
	    ok
    end,
    do_prim_purge_cache(T);
do_prim_purge_cache([]) ->
    ok.

prim_set_primary_archive(PS, undefined, undefined, undefined, _ParserFun) ->
    debug(PS, {set_primary_archive, clean}),
    case PS#prim_state.primary_archive of
        undefined ->
            Res = {error, enoent},
            debug(PS, {return, Res}),
            {Res, PS};
        ArchiveFile ->
            {primary, PrimZip, _FI, _ParserFun2} = erase(ArchiveFile),
            ok = prim_zip:close(PrimZip),
            PS2 = PS#prim_state{primary_archive = undefined},
            Res = {ok, []},
            debug(PS2, {return, Res}),
            {Res, PS2}
    end;

prim_set_primary_archive(PS, ArchiveFile0, ArchiveBin,
			 #file_info{} = FileInfo, ParserFun)
  when is_list(ArchiveFile0), is_binary(ArchiveBin) ->
    %% Try the archive file
    debug(PS, {set_primary_archive, ArchiveFile0, byte_size(ArchiveBin)}),
    ArchiveFile = real_path(absname(ArchiveFile0)),
    {Res3, PS3} =
        case PS#prim_state.primary_archive of
            undefined ->
                case load_prim_archive(ArchiveFile, ArchiveBin, FileInfo) of
                    {ok, PrimZip, FI, Ebins} ->
                        debug(PS, {set_primary_archive, Ebins}),
                        put(ArchiveFile, {primary, PrimZip, FI, ParserFun}),
                        {{ok, Ebins},
                         PS#prim_state{primary_archive = ArchiveFile}};
                    Error ->
                        debug(PS, {set_primary_archive, Error}),
                        {Error, PS}
                end;
            OldArchiveFile ->
                debug(PS, {set_primary_archive, clean}),
                {primary, PrimZip, _FI, _ParserFun} = erase(OldArchiveFile),
                ok = prim_zip:close(PrimZip),
                PS2 = PS#prim_state{primary_archive = undefined},
                prim_set_primary_archive(PS2, ArchiveFile, ArchiveBin,
					 FileInfo, ParserFun)
        end,
    debug(PS3, {return, Res3}),
    {Res3, PS3}.

-spec prim_get_file(prim_state(), file:filename()) -> {_, prim_state()}.
prim_get_file(PS, File) ->
    debug(PS, {get_file, File}),
    {Res2, PS2} =
        case name_split(PS#prim_state.primary_archive, File) of
            {file, PrimFile} ->
                Res = prim_file:read_file(PrimFile),
                {Res, PS};
            {archive, ArchiveFile, FileInArchive} ->
                debug(PS, {archive_get_file, ArchiveFile, FileInArchive}),
                FileComponents = path_split(FileInArchive),
                Fun =
                    fun({Components, _GetInfo, GetBin}, Acc) ->
                            if
                                Components =:= FileComponents ->
                                    {false, {ok, GetBin()}};
                                true ->
                                    {true, Acc}
                            end
                    end,
                apply_archive(PS, Fun, {error, enoent}, ArchiveFile)
        end,
    debug(PS, {return, Res2}),
    {Res2, PS2}.    

-spec prim_list_dir(prim_state(), file:filename()) ->
	 {{'ok', [file:filename()]}, prim_state()}
       | {{'error', term()}, prim_state()}.
prim_list_dir(PS, Dir) ->
    debug(PS, {list_dir, Dir}),
    {Res2, PS3} =
        case name_split(PS#prim_state.primary_archive, Dir) of
            {file, PrimDir} ->
                Res = prim_file:list_dir(PrimDir),
                {Res, PS};
            {archive, ArchiveFile, FileInArchive} ->
                debug(PS, {archive_list_dir, ArchiveFile, FileInArchive}),
                DirComponents = path_split(FileInArchive),
                Fun =
                    fun({Components, _GetInfo, _GetBin}, {Status, Names} = Acc) ->
                            case Components of
                                [RevName | DC] when DC =:= DirComponents ->
                                    case RevName of
                                        "" ->
                                            %% The listed directory
                                            {true, {ok, Names}};
                                        _ ->
                                            %% Plain file
                                            Name = reverse(RevName),
                                            {true, {Status, [Name | Names]}}
                                    end;
                                ["", RevName | DC] when DC =:= DirComponents ->
                                    %% Directory
                                    Name = reverse(RevName),
                                    {true, {Status, [Name | Names]}};
                                [RevName] when DirComponents =:= [""] ->
                                    %% File in top directory
                                    Name = reverse(RevName),
                                    {true, {ok, [Name | Names]}};
                                ["", RevName] when DirComponents =:= [""] ->
                                    %% Directory in top directory
                                    Name = reverse(RevName),
                                    {true, {ok, [Name | Names]}};
                                _ ->
                                    %% No match
                                    {true, Acc}
                            end
                    end,
                {{Status, Names}, PS2} =
                    apply_archive(PS, Fun, {error, []}, ArchiveFile),
                case Status of
                    ok    -> {{ok, Names}, PS2};
                    error -> {{error, enotdir}, PS2}
                end
        end,
    debug(PS, {return, Res2}),
    {Res2, PS3}.

-spec prim_read_file_info(prim_state(), file:filename(), boolean()) ->
	{{'ok', #file_info{}}, prim_state()}
      | {{'error', term()}, prim_state()}.
prim_read_file_info(PS, File, FollowLinks) ->
    debug(PS, {read_file_info, File}),
    {Res2, PS2} =
        case name_split(PS#prim_state.primary_archive, File) of
            {file, PrimFile} ->
                case FollowLinks of
                    true -> {prim_file:read_file_info(PrimFile), PS};
                    false -> {prim_file:read_link_info(PrimFile), PS}
                end;
            {archive, ArchiveFile, []} ->
                %% Fake top directory
                debug(PS, {archive_read_file_info, ArchiveFile}),
                case prim_file:read_file_info(ArchiveFile) of
                    {ok, FI} ->
                        {{ok, FI#file_info{type = directory}}, PS};
                    Other ->
                        {Other, PS}
                end;
            {archive, ArchiveFile, FileInArchive} ->
                debug(PS, {archive_read_file_info, File}),
                FileComponents = path_split(FileInArchive),
                Fun =
                    fun({Components, GetInfo, _GetBin}, Acc)  ->
			    case Components of
				["" | F] when F =:= FileComponents ->
                                    %% Directory
                                    {false, {ok, GetInfo()}};
                                F when F =:= FileComponents ->
                                    %% Plain file
                                    {false, {ok, GetInfo()}};
                                _ ->
                                    %% No match
                                    {true, Acc}
                            end
                    end,
                apply_archive(PS, Fun, {error, enoent}, ArchiveFile)
        end,
    debug(PS2, {return, Res2}),
    {Res2, PS2}.

-spec prim_get_cwd(prim_state(), [file:filename()]) ->
        {{'error', term()} | {'ok', _}, prim_state()}.
prim_get_cwd(PS, []) ->
    debug(PS, {get_cwd, []}),
    Res = prim_file:get_cwd(),
    debug(PS, {return, Res}),
    {Res, PS};
prim_get_cwd(PS, [Drive]) ->
    debug(PS, {get_cwd, Drive}),
    Res = prim_file:get_cwd(Drive),
    debug(PS, {return, Res}),
    {Res, PS}.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

apply_archive(PS, Fun, Acc, Archive) ->
    case get(Archive) of
        undefined ->
	    case open_archive(Archive, Acc, Fun) of
		{ok, PrimZip, {Acc2, FI, _}} ->
		    debug(PS, {cache, ok}),
		    put(Archive, {{ok, PrimZip}, FI}),
		    {Acc2, PS};
		Error ->
		    debug(PS, {cache, Error}),
		    %% put(Archive, {Error, FI}),
		    {Error, PS}
	    end;
        {primary, PrimZip, FI, ParserFun} ->
	    case prim_file:read_file_info(Archive) of
                {ok, FI2} 
		  when FI#file_info.mtime =:= FI2#file_info.mtime ->
		    case foldl_archive(PrimZip, Acc, Fun) of
			{ok, _PrimZip2, Acc2} ->
			    {Acc2, PS};
			Error ->
			    debug(PS, {primary, Error}),
			    {Error, PS}
		    end;
		{ok, FI2} ->
		    ok = clear_cache(Archive, {ok, PrimZip}),
		    case load_prim_archive(Archive, FI2, ParserFun) of
			{ok, PrimZip2, FI3, _Ebins} ->
			    debug(PS, {cache, {update, Archive}}),
			    put(Archive, {primary, PrimZip2, FI3, ParserFun});
			Error2 ->
			    debug(PS, {cache, {clear, Error2}})
		    end,
		    apply_archive(PS, Fun, Acc, Archive);
		Error ->
		    debug(PS, {cache, {clear, Error}}),
		    ok = clear_cache(Archive, {ok, PrimZip}),
		    apply_archive(PS, Fun, Acc, Archive)
	    end;
        {Cache, FI} ->
            case prim_file:read_file_info(Archive) of
                {ok, FI2} 
		  when FI#file_info.mtime =:= FI2#file_info.mtime ->
                    case Cache of
                        {ok, PrimZip} ->
                            case foldl_archive(PrimZip, Acc, Fun) of
                                {ok, _PrimZip2, Acc2} ->
                                    {Acc2, PS};
                                Error ->
                                    debug(PS, {cache, {clear, Error}}),
                                    ok = clear_cache(Archive, Cache),
                                    debug(PS, {cache, Error}),
				    erase(Archive),
                                    %% put(Archive, {Error, FI}),
                                    {Error, PS}
                            end;
                        Error ->
                            debug(PS, {cache, Error}),
                            {Error, PS}
                    end;
                Error ->
                    debug(PS, {cache, {clear, Error}}),
                    ok = clear_cache(Archive, Cache),
                    apply_archive(PS, Fun, Acc, Archive)
            end
    end.

open_archive(Archive, Acc, Fun) ->
    case prim_file:read_file_info(Archive) of
	{ok, FileInfo} ->
	    open_archive(Archive, FileInfo, Acc, Fun);
	{error, Reason} ->
	    {error, Reason}
    end.

%% Open the given archive and iterate through all files with an own
%% wrapper fun in order to identify each file as a component list as
%% returned from path_split/1.
%%
%% In the archive (zip) file, directory elements might or might not be
%% present. To ensure consistency, a directory element is added if it
%% does not already exist (ensure_virtual_dirs/6). NOTE that there will
%% be no such directory element for the top directory of the archive.
open_archive(Archive, FileInfo, Acc, Fun) ->
    FakeFI = FileInfo#file_info{type = directory},
    Wrapper =
	fun({N, GI, GB}, {A, I, Dirs}) ->
		Components = path_split(N),
		Dirs2 =
		    case Components of
			["" | Dir] ->
			    %% This is a directory
			    [Dir | Dirs];
			_ ->
			    %% This is a regular file
			    Dirs
		    end,
		{Includes, Dirs3, A2} =
		    ensure_virtual_dirs(Components, Fun, FakeFI,
					[{true, Components}], Dirs2, A),
		{_Continue, A3} = Fun({Components, GI, GB}, A2),
		{true, Includes, {A3, I, Dirs3}}
	end,
    prim_zip:open(Wrapper, {Acc, FakeFI, []}, Archive).

ensure_virtual_dirs(Components, Fun, FakeFI, Includes, Dirs, Acc) ->
    case Components of
	[_] ->
	    %% Don't add virtual dir for top directory
	    {Includes, Dirs, Acc};
	[_ | Dir] ->
	    case lists:member(Dir, Dirs) of % BIF
		false ->
		    %% The directory does not yet exist - add it
		    GetInfo = fun() -> FakeFI end,
		    GetBin = fun() -> <<>> end,
		    VirtualDir = ["" | Dir],
		    Includes2 = [{true, VirtualDir, GetInfo, GetBin} | Includes],
		    Dirs2 = [Dir | Dirs],

		    %% Recursively ensure dir elements on all levels
		    {I, F, Acc2} = ensure_virtual_dirs(Dir, Fun, FakeFI,
						       Includes2, Dirs2, Acc),

		    {_Continue, Acc3} = Fun({VirtualDir, GetInfo, GetBin}, Acc2),
		    {I, F, Acc3};
		true ->
		    %% The directory element does already exist
		    %% Recursivly ensure dir elements on all levels
		    ensure_virtual_dirs(Dir,Fun,FakeFI,Includes,Dirs,Acc)
	    end
    end.

foldl_archive(PrimZip, Acc, Fun) ->
    Wrapper =
        fun({Components, GI, GB}, A) ->
                %% Allow partial iteration at foldl
                {Continue, A2} = Fun({Components, GI, GB}, A),
                {Continue, true, A2}
        end,                        
    prim_zip:foldl(Wrapper, Acc, PrimZip).

cache_new(PS) ->
    PS.

clear_cache(Archive, Cache) ->
    erase(Archive),
    case Cache of
        {ok, PrimZip} ->
            prim_zip:close(PrimZip);
        {error, _} ->
            ok
    end.

%%% --------------------------------------------------------
%%% Misc. functions.
%%% --------------------------------------------------------

%%% Look for directory separators
is_basename(File) ->
    case deep_member($/, File) of
        true -> 
            false;
        false ->
            case erlang:system_info(os_type) of
                {win32, _} ->
                    case File of
                        [_,$: | _] ->
			    false;
                        _ -> 
			    not deep_member($\\, File)
                    end;
                _ ->
                    true
            end
    end.

send_all(U, [IP | AL], Cmd) ->
    ?dbg(sendto, {U, IP, ?EBOOT_PORT, Cmd}),
    prim_inet:sendto(U, IP, ?EBOOT_PORT, Cmd),
    send_all(U, AL, Cmd);
send_all(_U, [], _) -> ok.

join(P, F) ->
    P ++ "/" ++ F.

member(X, [X|_]) -> true;
member(X, [_|Y]) -> member(X, Y);
member(_X, [])   -> false.

deep_member(X, [X|_]) -> 
    true;
deep_member(X, [List | Y]) when is_list(List) ->
    deep_member(X, List) orelse deep_member(X, Y);
deep_member(X, [Atom | Y]) when is_atom(Atom) ->
    deep_member(X, atom_to_list(Atom)) orelse deep_member(X, Y);
deep_member(X, [_ | Y]) -> 
    deep_member(X, Y);
deep_member(_X, [])   ->
    false.

keymember(X, I, [Y | _]) when element(I,Y) =:= X -> true;
keymember(X, I, [_ | T]) -> keymember(X, I, T);
keymember(_X, _I, []) -> false.

keysort(I, L) -> keysort(I, L, []).

keysort(I, [X | L], Ls) ->
    keysort(I, L, keyins(X, I, Ls));
keysort(_I, [], Ls) -> Ls.

keyins(X, I, [Y | T]) when X < element(I,Y) -> [X,Y|T];
keyins(X, I, [Y | T]) -> [Y | keyins(X, I, T)];
keyins(X, _I, []) -> [X].

to_strs([P|Paths]) when is_atom(P) ->
    [atom_to_list(P)|to_strs(Paths)];
to_strs([P|Paths]) when is_list(P) ->
    [P|to_strs(Paths)];
to_strs([_|Paths]) ->
    to_strs(Paths);
to_strs([]) ->
    [].

reverse([] = L) ->
    L;
reverse([_] = L) ->
    L;
reverse([A, B]) ->
    [B, A];
reverse([A, B | L]) ->
    lists:reverse(L, [B, A]). % BIF
                        
%% Returns a reversed list of path components, each component itself a
%% reversed list (string), e.g.
%% /path/to/file -> ["elif","ot","htap",""]
%% /path/to/dir/ -> ["","rid","ot","htap",""]
%% Note the "" marking leading and trailing / (slash).
path_split(List) ->
   path_split(List, [], []).

path_split([$/ | Tail], Path, Paths) ->
    path_split(Tail, [], [Path | Paths]);
path_split([Head | Tail], Path, Paths) ->
    path_split(Tail, [Head | Path], Paths);
path_split([], Path, Paths) ->
    [Path | Paths].

%% The opposite of path_split/1
path_join(Paths) ->
    path_join(Paths,[]).

path_join([""],Acc) ->
    Acc;
path_join([Path],Acc) ->
    reverse(Path) ++ Acc;
path_join([Path|Paths],Acc) ->
    path_join(Paths,"/" ++ reverse(Path) ++ Acc).

name_split(undefined, File) ->
    %% Ignore primary archive
    RevExt = reverse(init:archive_extension()),
    case archive_split(File, RevExt, []) of
        no_split ->
            {file, File};
	Archive ->
	    Archive
    end;
name_split(ArchiveFile, File0) ->
    %% Look first in primary archive
    File = absname(File0),
    case string_match(real_path(File), ArchiveFile) of
        no_match ->
            %% Archive or plain file
            name_split(undefined, File);
        {match, FileInArchive} ->
            %% Primary archive
	    {archive, ArchiveFile, FileInArchive}
    end.

string_match([Char | File], [Char | Archive]) ->
    string_match(File, Archive);
string_match([] = File, []) ->
    {match, File};
string_match([$/ | File], []) ->
    {match, File};
string_match(_File, _Archive) ->
    no_match.

archive_split("/"++File, RevExt, Acc) ->
    case is_prefix(RevExt, Acc) of
	false ->
	    archive_split(File, RevExt, [$/|Acc]);
	true ->
	    ArchiveFile = absname(reverse(Acc)),
	    {archive, ArchiveFile, File}
    end;
archive_split([H|T], RevExt, Acc) ->
    archive_split(T, RevExt, [H|Acc]);
archive_split([], RevExt, Acc) ->
    case is_prefix(RevExt, Acc) of
	false ->
	    no_split;
	true ->
	    ArchiveFile = absname(reverse(Acc)),
	    {archive, ArchiveFile, []}
    end.

is_prefix([H|T1], [H|T2]) -> is_prefix(T1, T2);
is_prefix([_|_], _) -> false;
is_prefix([], _ ) -> true.

%% Parse list of ipv4 addresses 
ipv4_list([H | T]) ->
    case ipv4_address(H) of
        {ok,IP} -> [IP | ipv4_list(T)];
        _ -> ipv4_list(T)
    end;
ipv4_list([]) -> [].
    
%%
%% Parse Ipv4 address: d1.d2.d3.d4 (from inet_parse)
%%
%% Return {ok, IP} | {error, einval}
%%
ipv4_address(Cs) ->
    case catch ipv4_addr(Cs, []) of
        {'EXIT',_} -> {error,einval};
        Addr -> {ok,Addr}
    end.

ipv4_addr([C | Cs], IP) when C >= $0, C =< $9 -> ipv4_addr(Cs, C-$0, IP).

ipv4_addr([$.|Cs], N, IP) when N < 256 -> ipv4_addr(Cs, [N|IP]);
ipv4_addr([C|Cs], N, IP) when C >= $0, C =< $9 ->
    ipv4_addr(Cs, N*10 + (C-$0), IP);
ipv4_addr([], D, [C,B,A]) when D < 256 -> {A,B,C,D}.

%% A simplified version of filename:absname/1
absname(Name) ->
    Name2 = normalize(Name, []),
    case pathtype(Name2) of
	absolute ->
	    Name2;
	relative ->
	    case prim_file:get_cwd() of
		{ok, Cwd} ->
		    Cwd ++ "/" ++ Name2;
		{error, _} ->
		    Name2
	    end;
	volumerelative ->
	    case prim_file:get_cwd() of
		{ok, Cwd} ->
		    absname_vr(Name2, Cwd);
		{error, _} ->
		    Name2
	    end
    end.

%% Assumes normalized name
absname_vr([$/ | NameRest], [Drive, $\: | _]) ->
    %% Absolute path on current drive.
    [Drive, $\: | NameRest];
absname_vr([Drive, $\: | NameRest], [Drive, $\: | _] = Cwd) ->
    %% Relative to current directory on current drive.
    Cwd ++ "/" ++ NameRest;
absname_vr([Drive, $\: | NameRest], _) ->
    %% Relative to current directory on another drive.
    case prim_file:get_cwd([Drive, $\:]) of
	{ok, DriveCwd}  ->
	    DriveCwd ++ "/" ++ NameRest;
	{error, _} ->
	    [Drive, $\:, $/] ++ NameRest
    end.

%% Assumes normalized name
pathtype(Name) when is_list(Name) -> 
    case erlang:system_info(os_type) of
	{unix, _}  -> 
	    unix_pathtype(Name);
	{win32, _} ->
	    win32_pathtype(Name)
    end.

unix_pathtype(Name) ->
    case Name of
	[$/|_] ->
	    absolute;
	[List|Rest] when is_list(List) ->
	    unix_pathtype(List++Rest);
	[Atom|Rest] when is_atom(Atom) ->
	    atom_to_list(Atom)++Rest;
	_ ->
	    relative
    end.

win32_pathtype(Name) ->
    case Name of
	[List|Rest] when is_list(List) ->
	    win32_pathtype(List++Rest);
	[Atom|Rest] when is_atom(Atom) ->
	    win32_pathtype(atom_to_list(Atom)++Rest);
	[Char, List | Rest] when is_list(List) ->
	    win32_pathtype([Char | List++Rest]);
	[$/, $/|_] -> 
	    absolute;
	[$/|_] -> 
	    volumerelative;
	[C1, C2, List | Rest] when is_list(List) ->
	    win32_pathtype([C1, C2|List ++ Rest]);
	[_Letter, $:, $/|_] -> 
	    absolute;
	[_Letter, $:|_] -> 
	    volumerelative;
	_ -> 
	    relative
    end.

normalize(Name, Acc) ->
    case Name of
	[List | Rest] when is_list(List) ->
	    normalize(List ++ Rest, Acc);
	[Atom | Rest] when is_atom(Atom) ->
	    normalize(atom_to_list(Atom) ++ Rest, Acc);
	[$\\ | Chars] ->
	    case erlang:system_info(os_type) of
                {win32, _} ->
		    normalize(Chars, [$/ | Acc]);
		_ ->
		    normalize(Chars, [$\\ | Acc])
	    end;
	[Char | Chars] ->
	    normalize(Chars, [Char | Acc]);
	[] ->
	    reverse(Acc)
    end.

%% Remove .. and . from the path, e.g.
%% /path/./to/this/../file -> /path/to/file
%% This includes resolving symlinks.
%%
%% This is done to ensure that paths are totally normalized before
%% comparing to find out if a file is inside the primary archive or
%% not.
real_path(Name) ->
    real_path(Name,reverse(path_split(Name)),[],[]).

real_path(_Name,[],Acc,_Links) ->
    path_join(Acc);
real_path(Name,["."|Paths],Acc,Links) ->
    real_path(Name,Paths,Acc,Links);
real_path(Name,[".."|Paths],[""]=Acc,Links) ->
    %% /.. -> / (can't get higher than root)
    real_path(Name,Paths,Acc,Links);
real_path(Name,[".."|Paths],[Prev|Acc],Links) when Prev=/=".." ->
    real_path(Name,Paths,Acc,Links);
real_path(Name,[Path|Paths],Acc,Links) ->
    This = [Path|Acc],
    ThisFile = path_join(This),
    case lists:member(ThisFile,Links) of
	true -> % circular!!
	    Name;
	false ->
	    case prim_file:read_link(ThisFile) of
		{ok,Link} ->
		    case reverse(path_split(Link)) of
			[""|_] = LinkPaths ->
			    real_path(Name,LinkPaths++Paths,[],[ThisFile|Links]);
			LinkPaths ->
                % windows currently does not allow creation of relative symlinks
                % across different drives
				case erlang:system_info(os_type) of
                 {win32, _} ->
                     real_path(Name,LinkPaths++Paths,[],[ThisFile|Links]);
                 _ ->
                     real_path(Name,LinkPaths++Paths,Acc,[ThisFile|Links])
                end
		    end;
		_ ->
		    real_path(Name,Paths,This,Links)
	    end
    end.

load_prim_archive(ArchiveFile, ArchiveBin, #file_info{}=FileInfo) ->
    Fun = fun({Components, _GI, _GB}, A) ->
		  case Components of
		      ["", "nibe", RevApp] -> % Reverse ebin
			  %% Collect ebin directories in archive
			  Ebin = lists:reverse(RevApp, "/ebin"),
			  {true, [Ebin | A]};
		      _ ->
			  {true, A}
		  end
	  end,
    Ebins0 = [ArchiveFile],
    case open_archive({ArchiveFile, ArchiveBin}, FileInfo,
		      Ebins0, Fun) of
	{ok, PrimZip, {RevEbins, FI, _}} ->
	    Ebins = reverse(RevEbins),
	    {ok, PrimZip, FI, Ebins};
	Error ->
	    Error
    end;
load_prim_archive(ArchiveFile, FileInfo, ParserFun) ->
    case ParserFun(ArchiveFile) of
	{ok, ArchiveBin} ->
	    load_prim_archive(ArchiveFile, ArchiveBin, FileInfo);
	Error ->
	    Error
    end.