%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 1997-2010. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in %% compliance with the License. You should have received a copy of the %% Erlang Public License along with this software. If not, it can be %% retrieved online at http://www.erlang.org/. %% %% Software distributed under the License is distributed on an "AS IS" %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See %% the License for the specific language governing rights and limitations %% under the License. %% %% %CopyrightEnd% %% -module(ram_file). %% Binary RAM file interface %% Generic file contents operations -export([open/2, close/1]). -export([write/2, read/2, copy/3, pread/2, pread/3, pwrite/2, pwrite/3, position/2, truncate/1, datasync/1, sync/1]). %% Specialized file operations -export([get_size/1, get_file/1, set_file/2, get_file_close/1]). -export([compress/1, uncompress/1, uuencode/1, uudecode/1, advise/4]). -export([allocate/3]). -export([open_mode/1]). %% used by ftp-file -export([ipread_s32bu_p32bu/3]). %% Includes and defines -define(RAM_FILE_DRV, "ram_file_drv"). -define(MAX_I32, (1 bsl 31)). -define(G_I32(X), is_integer(X), X >= -?MAX_I32, X < ?MAX_I32). -include("file.hrl"). %% -------------------------------------------------------------------------- %% These operation codes were once identical between efile_drv.c %% and ram_file_drv.c, but now these drivers are not depeding on each other. %% So, the codes could be changed to more logical values now, but why indeed? %% Defined "file" functions -define(RAM_FILE_OPEN, 1). -define(RAM_FILE_READ, 2). -define(RAM_FILE_LSEEK, 3). -define(RAM_FILE_WRITE, 4). -define(RAM_FILE_FSYNC, 9). -define(RAM_FILE_TRUNCATE, 14). -define(RAM_FILE_PREAD, 17). -define(RAM_FILE_PWRITE, 18). -define(RAM_FILE_FDATASYNC, 19). %% Other operations -define(RAM_FILE_GET, 30). -define(RAM_FILE_SET, 31). -define(RAM_FILE_GET_CLOSE, 32). -define(RAM_FILE_COMPRESS, 33). -define(RAM_FILE_UNCOMPRESS, 34). -define(RAM_FILE_UUENCODE, 35). -define(RAM_FILE_UUDECODE, 36). -define(RAM_FILE_SIZE, 37). -define(RAM_FILE_ADVISE, 38). -define(RAM_FILE_ALLOCATE, 39). %% Open modes for RAM_FILE_OPEN -define(RAM_FILE_MODE_READ, 1). -define(RAM_FILE_MODE_WRITE, 2). -define(RAM_FILE_MODE_READ_WRITE, 3). %% Use this mask to get just the mode bits to be passed to the driver. -define(RAM_FILE_MODE_MASK, 3). %% Seek modes for RAM_FILE_LSEEK -define(RAM_FILE_SEEK_SET, 0). -define(RAM_FILE_SEEK_CUR, 1). -define(RAM_FILE_SEEK_END, 2). %% Return codes -define(RAM_FILE_RESP_OK, 0). -define(RAM_FILE_RESP_ERROR, 1). -define(RAM_FILE_RESP_DATA, 2). -define(RAM_FILE_RESP_NUMBER, 3). -define(RAM_FILE_RESP_INFO, 4). %% POSIX file advises -define(POSIX_FADV_NORMAL, 0). -define(POSIX_FADV_RANDOM, 1). -define(POSIX_FADV_SEQUENTIAL, 2). -define(POSIX_FADV_WILLNEED, 3). -define(POSIX_FADV_DONTNEED, 4). -define(POSIX_FADV_NOREUSE, 5). %% -------------------------------------------------------------------------- %% Generic file contents operations. %% %% Supposed to be called by applications through module file. open(Data, ModeList) when is_list(ModeList) -> case open_mode(ModeList) of {Mode,Opts} when is_integer(Mode) -> case ll_open(Data, Mode, Opts) of {ok,Port} -> {ok,#file_descriptor{module=?MODULE, data=Port}}; Error -> Error end; {error,_}=Error -> Error end; %% Old obsolete mode specification open(Data, Mode) -> case mode_list(Mode) of ModeList when is_list(ModeList) -> open(Data, ModeList); Error -> Error end. close(#file_descriptor{module = ?MODULE, data = Port}) -> ll_close(Port). read(#file_descriptor{module = ?MODULE, data = Port}, Sz) when is_integer(Sz), Sz >= 0 -> if ?G_I32(Sz) -> Cmd = <<?RAM_FILE_READ:8,Sz:32>>, case call_port(Port, Cmd) of {ok, {0, _Data}} when Sz =/= 0 -> eof; {ok, {_Sz, Data}} -> {ok, Data}; {error, enomem} -> %% Garbage collecting here might help if %% the current processes has some old binaries left. erlang:garbage_collect(), case call_port(Port, Cmd) of {ok, {0, _Data}} when Sz =/= 0 -> eof; {ok, {_Sz, Data}} -> {ok, Data}; Error -> Error end; Error -> Error end; true -> {error, einval} end. write(#file_descriptor{module = ?MODULE, data = Port}, Bytes) -> case call_port(Port, [?RAM_FILE_WRITE | Bytes]) of {ok, _Sz} -> ok; Error -> Error end. copy(#file_descriptor{module = ?MODULE} = Source, #file_descriptor{module = ?MODULE} = Dest, Length) when is_integer(Length), Length >= 0; is_atom(Length) -> %% XXX Should be moved down to the driver for optimization. file:copy_opened(Source, Dest, Length). datasync(#file_descriptor{module = ?MODULE, data = Port}) -> call_port(Port, <<?RAM_FILE_FDATASYNC>>). sync(#file_descriptor{module = ?MODULE, data = Port}) -> call_port(Port, <<?RAM_FILE_FSYNC>>). truncate(#file_descriptor{module = ?MODULE, data = Port}) -> call_port(Port, <<?RAM_FILE_TRUNCATE>>). position(#file_descriptor{module = ?MODULE, data = Port}, Pos) -> case lseek_position(Pos) of {ok, Offs, Whence} when ?G_I32(Offs) -> call_port(Port, <<?RAM_FILE_LSEEK:8,Offs:32,Whence:32>>); {ok, _, _} -> {error, einval}; Error -> Error end. pread(#file_descriptor{module = ?MODULE, data = Port}, L) when is_list(L) -> pread_1(Port, L, []). pread_1(Port, [], Cs) -> pread_2(Port, lists:reverse(Cs), []); pread_1(Port, [{At, Sz} | T], Cs) when is_integer(At), is_integer(Sz), Sz >= 0 -> if ?G_I32(At), ?G_I32(Sz) -> pread_1(Port, T, [{Sz,<<?RAM_FILE_PREAD:8,At:32,Sz:32>>}|Cs]); true -> {error, einval} end; pread_1(_, _, _243) -> {error, badarg}. pread_2(_Port, [], R) -> {ok, lists:reverse(R)}; pread_2(Port, [{Sz,Command}|Commands], R) -> case call_port(Port, Command) of {ok, {0,_Data}} when Sz =/= 0 -> pread_2(Port, Commands, [eof | R]); {ok, {_Sz,Data}} -> pread_2(Port, Commands, [Data | R]); Error -> Error end. pread(#file_descriptor{module = ?MODULE, data = Port}, At, Sz) when is_integer(At), is_integer(Sz), Sz >= 0 -> if ?G_I32(At), ?G_I32(Sz) -> case call_port(Port, <<?RAM_FILE_PREAD:8,At:32,Sz:32>>) of {ok, {0,_Data}} when Sz =/= 0 -> eof; {ok, {_Sz,Data}} -> {ok, Data}; Error -> Error end; true -> {error, einval} end; pread(#file_descriptor{module = ?MODULE}, _, _) -> {error, badarg}. pwrite(#file_descriptor{module = ?MODULE, data = Port}, L) when is_list(L) -> pwrite_1(Port, L, 0, []). pwrite_1(Port, [], _, Cs) -> pwrite_2(Port, lists:reverse(Cs), 0); pwrite_1(Port, [{At, Bytes} | T], R, Cs) when is_integer(At) -> if ?G_I32(At), is_binary(Bytes) -> pwrite_1(Port, T, R+1, [<<?RAM_FILE_PWRITE:8,At:32,Bytes/binary>> | Cs]); ?G_I32(At) -> try erlang:iolist_to_binary(Bytes) of Bin -> pwrite_1(Port, T, R+1, [<<?RAM_FILE_PWRITE:8,At:32,Bin/binary>> | Cs]) catch error:Reason -> {error, Reason} end; true -> {error, {R, einval}} end; pwrite_1(_, _, _, _) -> {error, badarg}. pwrite_2(_Port, [], _R) -> ok; pwrite_2(Port, [Command|Commands], R) -> case call_port(Port, Command) of {ok, _Sz} -> pwrite_2(Port, Commands, R+1); {error, badarg} = Error -> Error; {error, Reason} -> {error, {R, Reason}} end. pwrite(#file_descriptor{module = ?MODULE, data = Port}, At, Bytes) when is_integer(At) -> if ?G_I32(At) -> case call_port(Port, [<<?RAM_FILE_PWRITE:8,At:32>>|Bytes]) of {ok, _Sz} -> ok; Error -> Error end; true -> {error, einval} end; pwrite(#file_descriptor{module = ?MODULE}, _, _) -> {error, badarg}. ipread_s32bu_p32bu(#file_descriptor{module = ?MODULE} = Handle, Pos, MaxSz) -> file:ipread_s32bu_p32bu_int(Handle, Pos, MaxSz). %% -------------------------------------------------------------------------- %% Specialized ram_file API for functions not in file, unique to ram_file. %% get_file(#file_descriptor{module = ?MODULE, data = Port}) -> case call_port(Port, [?RAM_FILE_GET]) of {ok, {_Sz, Data}} -> {ok, Data}; Error -> Error end; get_file(#file_descriptor{}) -> {error, enotsup}. set_file(#file_descriptor{module = ?MODULE, data = Port}, Data) -> call_port(Port, [?RAM_FILE_SET | Data]); set_file(#file_descriptor{}, _) -> {error, enotsup}. get_file_close(#file_descriptor{module = ?MODULE, data = Port}) -> case call_port(Port, [?RAM_FILE_GET_CLOSE]) of {ok, {_Sz, Data}} -> {ok, Data}; Error -> Error end; get_file_close(#file_descriptor{}) -> {error, enotsup}. get_size(#file_descriptor{module = ?MODULE, data = Port}) -> call_port(Port, [?RAM_FILE_SIZE]); get_size(#file_descriptor{}) -> {error, enotsup}. compress(#file_descriptor{module = ?MODULE, data = Port}) -> call_port(Port, [?RAM_FILE_COMPRESS]); compress(#file_descriptor{}) -> {error, enotsup}. uncompress(#file_descriptor{module = ?MODULE, data = Port}) -> call_port(Port, [?RAM_FILE_UNCOMPRESS]); uncompress(#file_descriptor{}) -> {error, enotsup}. uuencode(#file_descriptor{module = ?MODULE, data = Port}) -> call_port(Port, [?RAM_FILE_UUENCODE]); uuencode(#file_descriptor{}) -> {error, enotsup}. uudecode(#file_descriptor{module = ?MODULE, data = Port}) -> call_port(Port, [?RAM_FILE_UUDECODE]); uudecode(#file_descriptor{}) -> {error, enotsup}. advise(#file_descriptor{module = ?MODULE, data = Port}, Offset, Length, Advise) -> Cmd0 = <<?RAM_FILE_ADVISE, Offset:64/signed, Length:64/signed>>, case Advise of normal -> call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NORMAL:32/signed>>); random -> call_port(Port, <<Cmd0/binary, ?POSIX_FADV_RANDOM:32/signed>>); sequential -> call_port(Port, <<Cmd0/binary, ?POSIX_FADV_SEQUENTIAL:32/signed>>); will_need -> call_port(Port, <<Cmd0/binary, ?POSIX_FADV_WILLNEED:32/signed>>); dont_need -> call_port(Port, <<Cmd0/binary, ?POSIX_FADV_DONTNEED:32/signed>>); no_reuse -> call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NOREUSE:32/signed>>); _ -> {error, einval} end; advise(#file_descriptor{}, _Offset, _Length, _Advise) -> {error, enotsup}. allocate(#file_descriptor{module = ?MODULE, data = Port}, Offset, Length) -> call_port(Port, <<?RAM_FILE_ALLOCATE, Offset:64/signed, Length:64/signed>>); allocate(#file_descriptor{}, _Offset, _Length) -> {error, enotsup}. %%%----------------------------------------------------------------- %%% Functions to communicate with the driver ll_open(Data, Mode, Opts) -> try erlang:open_port({spawn, ?RAM_FILE_DRV}, Opts) of Port -> case call_port(Port, [<<?RAM_FILE_OPEN:8,Mode:32>>|Data]) of {error, _} = Error -> ll_close(Port), Error; {ok, _} -> {ok, Port} end catch error:Reason -> {error, Reason} end. call_port(Port, Command) when is_port(Port), is_binary(Command) -> try erlang:port_command(Port, Command) of true -> get_response(Port) catch error:badarg -> {error, einval}; % Since Command is valid, Port must be dead error:Reason -> {error, Reason} end; call_port(Port, Command) -> try erlang:iolist_to_binary(Command) of Bin -> call_port(Port, Bin) catch error:Reason -> {error, Reason} end. get_response(Port) -> receive {Port, {data, [Response|Rest]}} -> translate_response(Response, Rest); {'EXIT', Port, _Reason} -> {error, port_died} end. ll_close(Port) -> try erlang:port_close(Port) catch error:_ -> ok end, receive %% In case the caller is the owner and traps exits {'EXIT', Port, _} -> ok after 0 -> ok end. %%%----------------------------------------------------------------- %%% Utility functions. mode_list(read) -> [read]; mode_list(write) -> [write]; mode_list(read_write) -> [read, write]; mode_list({binary, Mode}) when is_atom(Mode) -> [binary | mode_list(Mode)]; mode_list({character, Mode}) when is_atom(Mode) -> mode_list(Mode); mode_list(_) -> {error, badarg}. %% Converts a list of mode atoms into an mode word for the driver. %% Returns {Mode, Opts} wher Opts is a list of options for %% erlang:open_port/2, or {error, einval} upon failure. open_mode(List) when is_list(List) -> case open_mode(List, {0, []}) of {Mode, Opts} when Mode band (?RAM_FILE_MODE_READ bor ?RAM_FILE_MODE_WRITE) =:= 0 -> {Mode bor ?RAM_FILE_MODE_READ, Opts}; Other -> Other end. open_mode([ram|Rest], {Mode, Opts}) -> open_mode(Rest, {Mode, Opts}); open_mode([read|Rest], {Mode, Opts}) -> open_mode(Rest, {Mode bor ?RAM_FILE_MODE_READ, Opts}); open_mode([write|Rest], {Mode, Opts}) -> open_mode(Rest, {Mode bor ?RAM_FILE_MODE_WRITE, Opts}); open_mode([binary|Rest], {Mode, Opts}) -> open_mode(Rest, {Mode, [binary | Opts]}); open_mode([], {Mode, Opts}) -> {Mode, Opts}; open_mode(_, _) -> {error, badarg}. %% Converts a position tuple {bof, X} | {cur, X} | {eof, X} into %% {ok, Offset, OriginCode} for the driver. %% Returns {error, einval} upon failure. lseek_position(Pos) when is_integer(Pos) -> lseek_position({bof, Pos}); lseek_position(bof) -> lseek_position({bof, 0}); lseek_position(cur) -> lseek_position({cur, 0}); lseek_position(eof) -> lseek_position({eof, 0}); lseek_position({bof, Offset}) when is_integer(Offset) -> {ok, Offset, ?RAM_FILE_SEEK_SET}; lseek_position({cur, Offset}) when is_integer(Offset) -> {ok, Offset, ?RAM_FILE_SEEK_CUR}; lseek_position({eof, Offset}) when is_integer(Offset) -> {ok, Offset, ?RAM_FILE_SEEK_END}; lseek_position(_) -> {error, badarg}. translate_response(?RAM_FILE_RESP_OK, []) -> ok; translate_response(?RAM_FILE_RESP_OK, Data) -> {ok, Data}; translate_response(?RAM_FILE_RESP_ERROR, List) when is_list(List) -> {error, list_to_atom(List)}; translate_response(?RAM_FILE_RESP_NUMBER, [X1, X2, X3, X4]) -> {ok, i32(X1, X2, X3, X4)}; translate_response(?RAM_FILE_RESP_DATA, [X1, X2, X3, X4|Data]) -> {ok, {i32(X1, X2, X3, X4), Data}}; translate_response(X, Data) -> {error, {bad_response_from_port, X, Data}}. i32(X1,X2,X3,X4) -> (X1 bsl 24) bor (X2 bsl 16) bor (X3 bsl 8) bor X4.