%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2005-2013. 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%
%%
%%
%% Description: a gen_server implementing a simple
%% terminal (using the group module) for a CLI
%% over SSH
-module(ssh_cli).
-behaviour(ssh_channel).
-include("ssh.hrl").
-include("ssh_connect.hrl").
%% ssh_channel callbacks
-export([init/1, handle_ssh_msg/2, handle_msg/2, terminate/2]).
%% backwards compatibility
-export([listen/1, listen/2, listen/3, listen/4, stop/1]).
%% state
-record(state, {
cm,
channel,
pty,
group,
buf,
shell,
exec
}).
%%====================================================================
%% ssh_channel callbacks
%%====================================================================
%%--------------------------------------------------------------------
%% Function: init(Args) -> {ok, State}
%%
%% Description: Initiates the CLI
%%--------------------------------------------------------------------
init([Shell, Exec]) ->
{ok, #state{shell = Shell, exec = Exec}};
init([Shell]) ->
{ok, #state{shell = Shell}}.
%%--------------------------------------------------------------------
%% Function: handle_ssh_msg(Args) -> {ok, State} | {stop, ChannelId, State}
%%
%% Description: Handles channel messages received on the ssh-connection.
%%--------------------------------------------------------------------
handle_ssh_msg({ssh_cm, _ConnectionManager,
{data, _ChannelId, _Type, Data}},
#state{group = Group} = State) ->
Group ! {self(), {data, binary_to_list(Data)}},
{ok, State};
handle_ssh_msg({ssh_cm, ConnectionManager,
{pty, ChannelId, WantReply,
{TermName, Width, Height, PixWidth, PixHeight, Modes}}},
State0) ->
State = State0#state{pty =
#ssh_pty{term = TermName,
width = not_zero(Width, 80),
height = not_zero(Height, 24),
pixel_width = PixWidth,
pixel_height = PixHeight,
modes = Modes},
buf = empty_buf()},
set_echo(State),
ssh_connection:reply_request(ConnectionManager, WantReply,
success, ChannelId),
{ok, State};
handle_ssh_msg({ssh_cm, ConnectionManager,
{env, ChannelId, WantReply, _Var, _Value}}, State) ->
ssh_connection:reply_request(ConnectionManager,
WantReply, failure, ChannelId),
{ok, State};
handle_ssh_msg({ssh_cm, ConnectionManager,
{window_change, ChannelId, Width, Height, PixWidth, PixHeight}},
#state{buf = Buf, pty = Pty0} = State) ->
Pty = Pty0#ssh_pty{width = Width, height = Height,
pixel_width = PixWidth,
pixel_height = PixHeight},
{Chars, NewBuf} = io_request({window_change, Pty0}, Buf, Pty),
write_chars(ConnectionManager, ChannelId, Chars),
{ok, State#state{pty = Pty, buf = NewBuf}};
handle_ssh_msg({ssh_cm, ConnectionManager,
{shell, ChannelId, WantReply}}, State) ->
NewState = start_shell(ConnectionManager, State),
ssh_connection:reply_request(ConnectionManager, WantReply,
success, ChannelId),
{ok, NewState#state{channel = ChannelId,
cm = ConnectionManager}};
handle_ssh_msg({ssh_cm, ConnectionManager,
{exec, ChannelId, WantReply, Cmd}}, #state{exec=undefined} = State) ->
{Reply, Status} = exec(Cmd),
write_chars(ConnectionManager,
ChannelId, io_lib:format("~p\n", [Reply])),
ssh_connection:reply_request(ConnectionManager, WantReply,
success, ChannelId),
ssh_connection:exit_status(ConnectionManager, ChannelId, Status),
ssh_connection:send_eof(ConnectionManager, ChannelId),
{stop, ChannelId, State#state{channel = ChannelId, cm = ConnectionManager}};
handle_ssh_msg({ssh_cm, ConnectionManager,
{exec, ChannelId, WantReply, Cmd}}, State) ->
NewState = start_shell(ConnectionManager, Cmd, State),
ssh_connection:reply_request(ConnectionManager, WantReply,
success, ChannelId),
{ok, NewState#state{channel = ChannelId,
cm = ConnectionManager}};
handle_ssh_msg({ssh_cm, _ConnectionManager, {eof, _ChannelId}}, State) ->
{ok, State};
handle_ssh_msg({ssh_cm, _, {signal, _, _}}, State) ->
%% Ignore signals according to RFC 4254 section 6.9.
{ok, State};
handle_ssh_msg({ssh_cm, _, {exit_signal, ChannelId, _, Error, _}}, State) ->
Report = io_lib:format("Connection closed by peer ~n Error ~p~n",
[Error]),
error_logger:error_report(Report),
{stop, ChannelId, State};
handle_ssh_msg({ssh_cm, _, {exit_status, ChannelId, 0}}, State) ->
{stop, ChannelId, State};
handle_ssh_msg({ssh_cm, _, {exit_status, ChannelId, Status}}, State) ->
Report = io_lib:format("Connection closed by peer ~n Status ~p~n",
[Status]),
error_logger:error_report(Report),
{stop, ChannelId, State}.
%%--------------------------------------------------------------------
%% Function: handle_msg(Args) -> {ok, State} | {stop, ChannelId, State}
%%
%% Description: Handles other channel messages.
%%--------------------------------------------------------------------
handle_msg({ssh_channel_up, ChannelId, ConnectionManager},
#state{channel = ChannelId,
cm = ConnectionManager} = State) ->
{ok, State};
handle_msg({Group, Req}, #state{group = Group, buf = Buf, pty = Pty,
cm = ConnectionManager,
channel = ChannelId} = State) ->
{Chars, NewBuf} = io_request(Req, Buf, Pty),
write_chars(ConnectionManager, ChannelId, Chars),
{ok, State#state{buf = NewBuf}};
handle_msg({'EXIT', Group, _Reason}, #state{group = Group,
channel = ChannelId} = State) ->
{stop, ChannelId, State};
handle_msg(_, State) ->
{ok, State}.
%%--------------------------------------------------------------------
%% Function: terminate(Reason, State) -> void()
%% Description: Called when the channel process is trminated
%%--------------------------------------------------------------------
terminate(_Reason, _State) ->
ok.
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
exec(Cmd) ->
eval(parse(scan(Cmd))).
scan(Cmd) ->
erl_scan:string(Cmd).
parse({ok, Tokens, _}) ->
erl_parse:parse_exprs(Tokens);
parse(Error) ->
Error.
eval({ok, Expr_list}) ->
case (catch erl_eval:exprs(Expr_list,
erl_eval:new_bindings())) of
{value, Value, _NewBindings} ->
{Value, 0};
{'EXIT', {Error, _}} ->
{Error, -1};
Error ->
{Error, -1}
end;
eval(Error) ->
{Error, -1}.
%%% io_request, handle io requests from the user process,
%%% Note, this is not the real I/O-protocol, but the mockup version
%%% used between edlin and a user_driver. The protocol tags are
%%% similar, but the message set is different.
%%% The protocol only exists internally between edlin and a character
%%% displaying device...
%%% We are *not* really unicode aware yet, we just filter away characters
%%% beyond the latin1 range. We however handle the unicode binaries...
io_request({window_change, OldTty}, Buf, Tty) ->
window_change(Tty, OldTty, Buf);
io_request({put_chars, Cs}, Buf, Tty) ->
put_chars(bin_to_list(Cs), Buf, Tty);
io_request({put_chars, unicode, Cs}, Buf, Tty) ->
put_chars([Ch || Ch <- unicode:characters_to_list(Cs,unicode), Ch =< 255], Buf, Tty);
io_request({insert_chars, Cs}, Buf, Tty) ->
insert_chars(bin_to_list(Cs), Buf, Tty);
io_request({insert_chars, unicode, Cs}, Buf, Tty) ->
insert_chars([Ch || Ch <- unicode:characters_to_list(Cs,unicode), Ch =< 255], Buf, Tty);
io_request({move_rel, N}, Buf, Tty) ->
move_rel(N, Buf, Tty);
io_request({delete_chars,N}, Buf, Tty) ->
delete_chars(N, Buf, Tty);
io_request(beep, Buf, _Tty) ->
{[7], Buf};
%% New in R12
io_request({get_geometry,columns},Buf,Tty) ->
{ok, Tty#ssh_pty.width, Buf};
io_request({get_geometry,rows},Buf,Tty) ->
{ok, Tty#ssh_pty.height, Buf};
io_request({requests,Rs}, Buf, Tty) ->
io_requests(Rs, Buf, Tty, []);
io_request(tty_geometry, Buf, Tty) ->
io_requests([{move_rel, 0}, {put_chars, unicode, [10]}], Buf, Tty, []);
%{[], Buf};
io_request(_R, Buf, _Tty) ->
{[], Buf}.
io_requests([R|Rs], Buf, Tty, Acc) ->
{Chars, NewBuf} = io_request(R, Buf, Tty),
io_requests(Rs, NewBuf, Tty, [Acc|Chars]);
io_requests([], Buf, _Tty, Acc) ->
{Acc, Buf}.
%%% return commands for cursor navigation, assume everything is ansi
%%% (vt100), add clauses for other terminal types if needed
ansi_tty(N, L) ->
["\e[", integer_to_list(N), L].
get_tty_command(up, N, _TerminalType) ->
ansi_tty(N, $A);
get_tty_command(down, N, _TerminalType) ->
ansi_tty(N, $B);
get_tty_command(right, N, _TerminalType) ->
ansi_tty(N, $C);
get_tty_command(left, N, _TerminalType) ->
ansi_tty(N, $D).
-define(PAD, 10).
-define(TABWIDTH, 8).
%% convert input characters to buffer and to writeout
%% Note that the buf is reversed but the buftail is not
%% (this is handy; the head is always next to the cursor)
conv_buf([], AccBuf, AccBufTail, AccWrite, Col) ->
{AccBuf, AccBufTail, lists:reverse(AccWrite), Col};
conv_buf([13, 10 | Rest], _AccBuf, AccBufTail, AccWrite, _Col) ->
conv_buf(Rest, [], tl2(AccBufTail), [10, 13 | AccWrite], 0);
conv_buf([13 | Rest], _AccBuf, AccBufTail, AccWrite, _Col) ->
conv_buf(Rest, [], tl1(AccBufTail), [13 | AccWrite], 0);
conv_buf([10 | Rest], _AccBuf, AccBufTail, AccWrite, _Col) ->
conv_buf(Rest, [], tl1(AccBufTail), [10, 13 | AccWrite], 0);
conv_buf([C | Rest], AccBuf, AccBufTail, AccWrite, Col) ->
conv_buf(Rest, [C | AccBuf], tl1(AccBufTail), [C | AccWrite], Col + 1).
%%% put characters at current position (possibly overwriting
%%% characters after current position in buffer)
put_chars(Chars, {Buf, BufTail, Col}, _Tty) ->
{NewBuf, NewBufTail, WriteBuf, NewCol} =
conv_buf(Chars, Buf, BufTail, [], Col),
{WriteBuf, {NewBuf, NewBufTail, NewCol}}.
%%% insert character at current position
insert_chars([], {Buf, BufTail, Col}, _Tty) ->
{[], {Buf, BufTail, Col}};
insert_chars(Chars, {Buf, BufTail, Col}, Tty) ->
{NewBuf, _NewBufTail, WriteBuf, NewCol} =
conv_buf(Chars, Buf, [], [], Col),
M = move_cursor(NewCol + length(BufTail), NewCol, Tty),
{[WriteBuf, BufTail | M], {NewBuf, BufTail, NewCol}}.
%%% delete characters at current position, (backwards if negative argument)
delete_chars(0, {Buf, BufTail, Col}, _Tty) ->
{[], {Buf, BufTail, Col}};
delete_chars(N, {Buf, BufTail, Col}, Tty) when N > 0 ->
NewBufTail = nthtail(N, BufTail),
M = move_cursor(Col + length(NewBufTail) + N, Col, Tty),
{[NewBufTail, lists:duplicate(N, $ ) | M],
{Buf, NewBufTail, Col}};
delete_chars(N, {Buf, BufTail, Col}, Tty) -> % N < 0
NewBuf = nthtail(-N, Buf),
NewCol = Col + N,
M1 = move_cursor(Col, NewCol, Tty),
M2 = move_cursor(NewCol + length(BufTail) - N, NewCol, Tty),
{[M1, BufTail, lists:duplicate(-N, $ ) | M2],
{NewBuf, BufTail, NewCol}}.
%%% Window change, redraw the current line (and clear out after it
%%% if current window is wider than previous)
window_change(Tty, OldTty, Buf)
when OldTty#ssh_pty.width == Tty#ssh_pty.width ->
{[], Buf};
window_change(Tty, OldTty, {Buf, BufTail, Col}) ->
M1 = move_cursor(Col, 0, OldTty),
N = erlang:max(Tty#ssh_pty.width - OldTty#ssh_pty.width, 0) * 2,
S = lists:reverse(Buf, [BufTail | lists:duplicate(N, $ )]),
M2 = move_cursor(length(Buf) + length(BufTail) + N, Col, Tty),
{[M1, S | M2], {Buf, BufTail, Col}}.
%% move around in buffer, respecting pad characters
step_over(0, Buf, [?PAD | BufTail], Col) ->
{[?PAD | Buf], BufTail, Col+1};
step_over(0, Buf, BufTail, Col) ->
{Buf, BufTail, Col};
step_over(N, [C | Buf], BufTail, Col) when N < 0 ->
N1 = ifelse(C == ?PAD, N, N+1),
step_over(N1, Buf, [C | BufTail], Col-1);
step_over(N, Buf, [C | BufTail], Col) when N > 0 ->
N1 = ifelse(C == ?PAD, N, N-1),
step_over(N1, [C | Buf], BufTail, Col+1).
%%% an empty line buffer
empty_buf() -> {[], [], 0}.
%%% col and row from position with given width
col(N, W) -> N rem W.
row(N, W) -> N div W.
%%% move relative N characters
move_rel(N, {Buf, BufTail, Col}, Tty) ->
{NewBuf, NewBufTail, NewCol} = step_over(N, Buf, BufTail, Col),
M = move_cursor(Col, NewCol, Tty),
{M, {NewBuf, NewBufTail, NewCol}}.
%%% give move command for tty
move_cursor(A, A, _Tty) ->
[];
move_cursor(From, To, #ssh_pty{width=Width, term=Type}) ->
Tcol = case col(To, Width) - col(From, Width) of
0 -> "";
I when I < 0 -> get_tty_command(left, -I, Type);
I -> get_tty_command(right, I, Type)
end,
Trow = case row(To, Width) - row(From, Width) of
0 -> "";
J when J < 0 -> get_tty_command(up, -J, Type);
J -> get_tty_command(down, J, Type)
end,
[Tcol | Trow].
%% %%% write out characters
%% %%% make sure that there is data to send
%% %%% before calling ssh_connection:send
write_chars(ConnectionManager, ChannelId, Chars) ->
case erlang:iolist_size(Chars) of
0 ->
ok;
_ ->
ssh_connection:send(ConnectionManager, ChannelId,
?SSH_EXTENDED_DATA_DEFAULT, Chars)
end.
%%% tail, works with empty lists
tl1([_|A]) -> A;
tl1(_) -> [].
%%% second tail
tl2([_,_|A]) -> A;
tl2(_) -> [].
%%% nthtail as in lists, but no badarg if n > the length of list
nthtail(0, A) -> A;
nthtail(N, [_ | A]) when N > 0 -> nthtail(N-1, A);
nthtail(_, _) -> [].
ifelse(Cond, A, B) ->
case Cond of
true -> A;
_ -> B
end.
bin_to_list(B) when is_binary(B) ->
binary_to_list(B);
bin_to_list(L) when is_list(L) ->
lists:flatten([bin_to_list(A) || A <- L]);
bin_to_list(I) when is_integer(I) ->
I.
start_shell(ConnectionManager, State) ->
Shell = State#state.shell,
ShellFun = case is_function(Shell) of
true ->
{ok, User} =
ssh_userreg:lookup_user(ConnectionManager),
case erlang:fun_info(Shell, arity) of
{arity, 1} ->
fun() -> Shell(User) end;
{arity, 2} ->
{ok, PeerAddr} =
ssh_connection_manager:peer_addr(ConnectionManager),
fun() -> Shell(User, PeerAddr) end;
_ ->
Shell
end;
_ ->
Shell
end,
Echo = get_echo(State#state.pty),
Group = group:start(self(), ShellFun, [{echo, Echo}]),
State#state{group = Group, buf = empty_buf()}.
start_shell(_ConnectionManager, Cmd, #state{exec={M, F, A}} = State) ->
Group = group:start(self(), {M, F, A++[Cmd]}, [{echo, false}]),
State#state{group = Group, buf = empty_buf()};
start_shell(ConnectionManager, Cmd, #state{exec=Shell} = State) when is_function(Shell) ->
{ok, User} =
ssh_userreg:lookup_user(ConnectionManager),
ShellFun =
case erlang:fun_info(Shell, arity) of
{arity, 1} ->
fun() -> Shell(Cmd) end;
{arity, 2} ->
fun() -> Shell(Cmd, User) end;
{arity, 3} ->
{ok, PeerAddr} =
ssh_connection_manager:peer_addr(ConnectionManager),
fun() -> Shell(Cmd, User, PeerAddr) end;
_ ->
Shell
end,
Echo = get_echo(State#state.pty),
Group = group:start(self(), ShellFun, [{echo,Echo}]),
State#state{group = Group, buf = empty_buf()}.
% Pty can be undefined if the client never sets any pty options before
% starting the shell.
get_echo(undefined) ->
true;
get_echo(#ssh_pty{modes = Modes}) ->
case proplists:get_value(echo, Modes, 1) of
0 ->
false;
_ ->
true
end.
% Group is undefined if the pty options are sent between open and
% shell messages.
set_echo(#state{group = undefined}) ->
ok;
set_echo(#state{group = Group, pty = Pty}) ->
Echo = get_echo(Pty),
Group ! {self(), echo, Echo}.
not_zero(0, B) ->
B;
not_zero(A, _) ->
A.
%%% Backwards compatibility
%%--------------------------------------------------------------------
%% Function: listen(...) -> {ok,Pid} | ignore | {error,Error}
%% Description: Starts a listening server
%% Note that the pid returned is NOT the pid of this gen_server;
%% this server is started when an SSH connection is made on the
%% listening port
%%--------------------------------------------------------------------
listen(Shell) ->
listen(Shell, 22).
listen(Shell, Port) ->
listen(Shell, Port, []).
listen(Shell, Port, Opts) ->
listen(Shell, any, Port, Opts).
listen(Shell, HostAddr, Port, Opts) ->
ssh:daemon(HostAddr, Port, [{shell, Shell} | Opts]).
%%--------------------------------------------------------------------
%% Function: stop(Pid) -> ok
%% Description: Stops the listener
%%--------------------------------------------------------------------
stop(Pid) ->
ssh:stop_listener(Pid).
