release_handler.erl

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    Tar = filename:join(RelDir, ReleaseName ++ ".tar.gz"),
    do_check_file(Tar, regular),
    Rel = ReleaseName ++ ".rel",
    extract_rel_file(filename:join("releases", Rel), Tar, Root),
    RelFile = filename:join(RelDir, Rel),
    Release = check_rel(Root, RelFile, false),
    #release{vsn = Vsn} = Release,
    case lists:keysearch(Vsn, #release.vsn, Releases) of
	{value, _} -> throw({error, {existing_release, Vsn}});
	_          -> ok
    end,
    extract_tar(Root, Tar),
    NewReleases = [Release#release{status = unpacked} | Releases],
    write_releases(RelDir, NewReleases, false),
    Dir = filename:join([RelDir, Vsn]),
    copy_file(RelFile, Dir, false),
    {ok, NewReleases, Vsn}.

%% Note that this function is not executed by a client
%% release_handler.
clean_release(RelDir, ReleaseName) ->
    Tar = filename:join(RelDir, ReleaseName ++ ".tar.gz"),
    Rel = filename:join(RelDir, ReleaseName ++ ".rel"),
    file:delete(Tar),
    file:delete(Rel).
   
check_rel(Root, RelFile, Masters) ->
    check_rel(Root, RelFile, [], Masters).
check_rel(Root, RelFile, LibDirs, Masters) ->
    case consult(RelFile, Masters) of
	{ok, [RelData]} ->
	    check_rel_data(RelData, Root, LibDirs);
	{ok, _} ->
	    throw({error, {bad_rel_file, RelFile}});
	{error, Reason} when is_tuple(Reason) ->
	    throw({error, {bad_rel_file, RelFile}});
	{error, FileError} -> % FileError is posix atom | no_master
	    throw({error, {FileError, RelFile}})
    end.

check_rel_data({release, {Name, Vsn}, {erts, EVsn}, Libs}, Root, LibDirs) ->
    Libs2 =
	lists:map(fun(LibSpec) ->
			  Lib = element(1, LibSpec),
			  LibVsn = element(2, LibSpec),
			  LibName = lists:concat([Lib, "-", LibVsn]),
			  LibDir = 
			      case lists:keysearch(Lib, 1, LibDirs) of
				  {value, {_Lib, _Vsn, Dir}} ->
				      Path = filename:join(Dir,LibName),
				      check_path(Path),
				      Path;
				  _ ->
				      filename:join([Root, "lib", LibName])
			      end,
			  {Lib, LibVsn, LibDir}
		  end,
		  Libs),
    #release{name = Name, vsn = Vsn, erts_vsn = EVsn,
	     libs = Libs2, status = unpacking};
check_rel_data(RelData, _Root, _LibDirs) ->
    throw({error, {bad_rel_data, RelData}}).

check_path(Path) ->
    case file:read_file_info(Path) of
	{ok, Info} when Info#file_info.type==directory ->
	    ok;
	{ok, _Info} ->
	    throw({error, {not_a_directory, Path}});
	{error, _Reason} ->
	    throw({error, {no_such_directory, Path}})
    end.
    
do_check_install_release(RelDir, Vsn, Releases, Masters) ->
    case lists:keysearch(Vsn, #release.vsn, Releases) of
	{value, #release{status = current}} ->
	    {error, {already_installed, Vsn}};
	{value, Release} ->
	    LatestRelease = get_latest_release(Releases),
	    VsnDir = filename:join([RelDir, Vsn]),
	    check_file(filename:join(VsnDir, "start.boot"), regular, Masters),
	    IsRelup = check_opt_file(filename:join(VsnDir, "relup"), regular, Masters),
	    check_opt_file(filename:join(VsnDir, "sys.config"), regular, Masters),

	    %% Check that all required libs are present
	    Libs = Release#release.libs,
	    lists:foreach(fun({_Lib, _LibVsn, LibDir}) ->
				  check_file(LibDir, directory, Masters),
				  Ebin = filename:join(LibDir, "ebin"),
				  check_file(Ebin, directory, Masters)
			  end,
			  Libs),

	    if
		IsRelup ->
		    case get_rh_script(LatestRelease, Release, RelDir, Masters) of
			{ok, {CurrentVsn, Descr, Script}} ->
			    case catch check_script(Script, Libs) of
				ok ->
				    {ok, CurrentVsn, Descr};
				Else ->
				    Else
			    end;
			Error ->
			    Error
		    end;
		true ->
		    {ok, Vsn, ""}
	    end;
	_ ->
	    {error, {no_such_release, Vsn}}
    end.
	    
do_install_release(#state{start_prg = StartPrg,
			  rel_dir = RelDir, releases = Releases,
			  masters = Masters,
			  static_emulator = Static},
		   Vsn, Opts) ->
    case lists:keysearch(Vsn, #release.vsn, Releases) of
	{value, #release{status = current}} ->
	    {error, {already_installed, Vsn}};
	{value, Release} ->
	    LatestRelease = get_latest_release(Releases),
	    case get_rh_script(LatestRelease, Release, RelDir, Masters) of
		{ok, {CurrentVsn, Descr, Script}} ->
		    mon_nodes(true),
		    EnvBefore = application_controller:prep_config_change(),
		    Apps = change_appl_data(RelDir, Release, Masters),
		    LibDirs = Release#release.libs,
		    case eval_script(Script, Apps, LibDirs, Opts) of
			{ok, []} ->
			    application_controller:config_change(EnvBefore),
			    mon_nodes(false),
			    NewReleases = set_status(Vsn, current, Releases),
			    {ok, NewReleases, CurrentVsn, Descr};
			{ok, Unpurged} ->
			    application_controller:config_change(EnvBefore),
			    mon_nodes(false),
			    NewReleases = set_status(Vsn, current, Releases),
			    {ok, NewReleases, Unpurged, CurrentVsn, Descr};
			restart_new_emulator when Static == true ->
			    throw(static_emulator);
			restart_new_emulator ->
			    mon_nodes(false),
			    {value, PermanentRelease} = 
				lists:keysearch(permanent, #release.status,
						Releases), 
			    NReleases = set_status(Vsn, current, Releases),
			    NReleases2 = set_status(Vsn,tmp_current,NReleases),
			    write_releases(RelDir, NReleases2, Masters),
			    prepare_restart_new_emulator(StartPrg, RelDir,
							 Release, 
							 PermanentRelease, 
							 Masters),
			    {restart_new_emulator, CurrentVsn, Descr};
			Else ->
			    application_controller:config_change(EnvBefore),
			    mon_nodes(false),
			    Else
		    end;
		Error ->
		    Error
	    end;
	_ ->
	    {error, {no_such_release, Vsn}}
    end.

%%% This code chunk updates the services in one of two ways,
%%% Either the emulator is restarted, in which case the old service
%%% is to be removed and the new enabled, or the emulator is NOT restarted
%%% in which case we try to rename the old service to the new name and try
%%% to update heart's view of what service we are really running.
do_make_services_permanent(PermanentVsn,Vsn, PermanentEVsn, EVsn) ->
    PermName = hd(string:tokens(atom_to_list(node()),"@")) 
	++ "_" ++ PermanentVsn,
    Name = hd(string:tokens(atom_to_list(node()),"@")) 
	++ "_" ++ Vsn,
    case erlsrv:get_service(EVsn,Name) of
	{error, _Error} ->
	    %% We probably do not need to replace services, just 
	    %% rename.
	    case os:getenv("ERLSRV_SERVICE_NAME") == PermName of
		true ->
		    case erlsrv:rename_service(EVsn,PermName,Name) of
			{ok,_} ->
			    case erlsrv:get_service(EVsn,Name) of
				{error,Error2} ->
				    throw({error,Error2});
				_Data2 ->
				    %% The interfaces for doing this are
				    %% NOT published and may be subject to
				    %% change. Do NOT do this anywhere else!

				    os:putenv("ERLSRV_SERVICE_NAME", Name),

				    %% Restart heart port program, this 
				    %% function is only to be used here.
				    heart:cycle(),
				    ok
			    end;
			Error3 ->
			    throw({error,{service_rename_failed, Error3}})
		    end;
		false ->
		    throw({error,service_name_missmatch})
	    end;
	Data ->
	    UpdData = erlsrv:new_service(Name, Data, []),
	    case erlsrv:store_service(EVsn,UpdData) of
		ok ->
		    erlsrv:disable_service(PermanentEVsn, PermName),
		    erlsrv:enable_service(EVsn, Name),
		    erlsrv:remove_service(PermName),
		    %%% Read comments about these above...
		    os:putenv("ERLSRV_SERVICE_NAME", Name),
		    heart:cycle(),
		    ok;
		Error4 ->
		    throw(Error4)
	    end
    end.
	    
do_make_permanent(#state{releases = Releases,
			 rel_dir = RelDir, unpurged = Unpurged,
			 masters = Masters,
			 static_emulator = Static},
		  Vsn) ->
    case lists:keysearch(Vsn, #release.vsn, Releases) of
	{value, #release{erts_vsn = EVsn, status = Status}}
	  when Status /= unpacked, Status /= old, Status /= permanent ->
	    Dir = filename:join([RelDir, Vsn]),
	    Sys =
		case catch check_file(filename:join(Dir, "sys.config"),
				      regular, Masters) of
		    ok ->     filename:join(Dir, "sys");
		    _ -> false
		end,
	    Boot = filename:join(Dir, "start.boot"),
	    check_file(Boot, regular, Masters),
	    set_permanent_files(RelDir, EVsn, Vsn, Masters, Static),
	    NewReleases = set_status(Vsn, permanent, Releases),
	    write_releases(RelDir, NewReleases, Masters),
	    case os:type() of
		{win32, nt} ->
		    {value, PermanentRelease} = 
				lists:keysearch(permanent, #release.status,
						Releases),
		    PermanentVsn = PermanentRelease#release.vsn,
		    PermanentEVsn = PermanentRelease#release.erts_vsn,
		    case catch do_make_services_permanent(PermanentVsn, 
							  Vsn, 
							  PermanentEVsn,
							  EVsn)  of
			{error,Reason} ->
			    {error,{service_update_failed, Reason}};
			_ ->
			    ok
		    end;
		_ ->
		    ok
	    end,
	    init:make_permanent(filename:join(Dir, "start"), Sys),
	    {ok, NewReleases, brutal_purge(Unpurged)};
	{value, #release{status = permanent}} ->
	    {ok, Releases, Unpurged};
	{value, #release{status = Status}} ->
	    {error, {bad_status, Status}};
	false ->
	    {error, {no_such_release, Vsn}}
    end.


do_back_service(OldVersion, CurrentVersion,OldEVsn,CurrentEVsn) ->
    NN = hd(string:tokens(atom_to_list(node()),"@")),
    OldName = NN ++ "_" ++ OldVersion,
    CurrentName = NN ++ "_" ++ CurrentVersion,
    UpdData = case erlsrv:get_service(CurrentEVsn,CurrentName) of
		  {error, Error} ->
		      throw({error,Error});
		  Data ->
		      erlsrv:new_service(OldName, Data, [])
	      end,
    case erlsrv:store_service(OldEVsn,UpdData) of
	ok ->
	    erlsrv:disable_service(CurrentEVsn,CurrentName),
	    erlsrv:enable_service(OldEVsn,OldName);
	Error2 ->
	    throw(Error2)
    end,
    OldErlSrv = filename:nativename(erlsrv:erlsrv(OldEVsn)),
    CurrentErlSrv = filename:nativename(erlsrv:erlsrv(CurrentEVsn)),
    case heart:set_cmd(CurrentErlSrv ++ " remove " ++ CurrentName ++ 
		       " & " ++ OldErlSrv ++ " start " ++ OldName) of
	ok ->
	    ok;
	Error3 ->
	    throw({error, {'heart:set_cmd() error', Error3}})
    end.

do_reboot_old_release(#state{releases = Releases,
			     rel_dir = RelDir, masters = Masters,
			     static_emulator = Static},
		      Vsn) ->
    case lists:keysearch(Vsn, #release.vsn, Releases) of
	{value, #release{erts_vsn = EVsn, status = old}} ->
	    CurrentRunning = case os:type() of
				 {win32,nt} ->
				     %% Get the current release on NT
				     case lists:keysearch(permanent, 
							  #release.status,
							  Releases) of
					 false ->
					     lists:keysearch(current,
							     #release.status,
							     Releases);
					 {value,CR} ->
					     CR
				     end;
				 _ ->
				     false
			     end,
	    set_permanent_files(RelDir, EVsn, Vsn, Masters, Static),
	    NewReleases = set_status(Vsn, permanent, Releases),
	    write_releases(RelDir, NewReleases, Masters),
	    case os:type() of
		{win32,nt} ->
		    %% Edit up the services and set a reasonable heart 
		    %% command
		    do_back_service(Vsn,CurrentRunning#release.vsn,EVsn,
				   CurrentRunning#release.erts_vsn);
		_ ->
		    ok
	    end,
	    ok;
	{value, #release{status = Status}} ->
	    {error, {bad_status, Status}};
	false ->
	    {error, {no_such_release, Vsn}}
    end.

%%-----------------------------------------------------------------
%% Depending of if the release_handler is running in normal, client or
%% client with static emulator the new system version is made permanent
%% in different ways.
%%-----------------------------------------------------------------
set_permanent_files(RelDir, EVsn, Vsn, false, _) ->
    write_start(filename:join([RelDir, "start_erl.data"]),
		EVsn ++ " " ++ Vsn,
		false);
set_permanent_files(RelDir, EVsn, Vsn, Masters, false) ->
    write_start(filename:join([RelDir, "start_erl.data"]),
		EVsn ++ " " ++ Vsn,
		Masters);
set_permanent_files(RelDir, _EVsn, Vsn, Masters, _Static) ->
    VsnDir = filename:join([RelDir, Vsn]),
    set_static_files(VsnDir, RelDir, Masters).


do_remove_service(Vsn) ->
    %%% Very unconditionally remove the service.
    ServiceName = hd(string:tokens(atom_to_list(node()),"@")) 
	++ "_" ++ Vsn,
    erlsrv:remove_service(ServiceName).

do_remove_release(Root, RelDir, Vsn, Releases) ->
    % Decide which libs should be removed
    case lists:keysearch(Vsn, #release.vsn, Releases) of
	{value, #release{status = permanent}} ->
	    {error, {permanent, Vsn}};
	{value, #release{libs = RemoveLibs, vsn = Vsn, erts_vsn = EVsn}} ->
	    case os:type() of
		{win32, nt} ->
		    do_remove_service(Vsn);
		_ ->
		    ok
	    end,

	    NewReleases = lists:keydelete(Vsn, #release.vsn, Releases),
	    RemoveThese =
		lists:foldl(fun(#release{libs = Libs}, Remove) ->
				    diff_dir(Remove, Libs)
			    end, RemoveLibs, NewReleases),