%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2005-2017. 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%
%%
%%
%% Description: a gen_server implementing a simple
%% terminal (using the group module) for a CLI
%% over SSH
-module(ssh_cli).
-behaviour(ssh_server_channel).
-include("ssh.hrl").
-include("ssh_connect.hrl").
%% ssh_server_channel callbacks
-export([init/1, handle_ssh_msg/2, handle_msg/2, terminate/2]).
-export([dbg_trace/3]).
%% state
-record(state, {
cm,
channel,
pty,
group,
buf,
shell,
exec
}).
%%====================================================================
%% ssh_server_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, _ConnectionHandler,
{data, _ChannelId, _Type, Data}},
#state{group = Group} = State) ->
List = binary_to_list(Data),
to_group(List, Group),
{ok, State};
handle_ssh_msg({ssh_cm, ConnectionHandler,
{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(ConnectionHandler, WantReply,
success, ChannelId),
{ok, State};
handle_ssh_msg({ssh_cm, ConnectionHandler,
{env, ChannelId, WantReply, _Var, _Value}}, State) ->
ssh_connection:reply_request(ConnectionHandler,
WantReply, failure, ChannelId),
{ok, State};
handle_ssh_msg({ssh_cm, ConnectionHandler,
{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, undefined),
write_chars(ConnectionHandler, ChannelId, Chars),
{ok, State#state{pty = Pty, buf = NewBuf}};
handle_ssh_msg({ssh_cm, ConnectionHandler, {shell, ChannelId, WantReply}}, State) ->
NewState = start_shell(ConnectionHandler, State),
ssh_connection:reply_request(ConnectionHandler, WantReply, success, ChannelId),
{ok, NewState#state{channel = ChannelId,
cm = ConnectionHandler}};
handle_ssh_msg({ssh_cm, ConnectionHandler, {exec, ChannelId, WantReply, Cmd}}, S0) ->
case
case S0#state.exec of
{direct,F} ->
%% Exec called and a Fun or MFA is defined to use. The F returns the
%% value to return.
exec_direct(ConnectionHandler, F, Cmd);
undefined when S0#state.shell == ?DEFAULT_SHELL ->
%% Exec called and the shell is the default shell (= Erlang shell).
%% To be exact, eval the term as an Erlang term (but not using the
%% ?DEFAULT_SHELL directly). This disables banner, prompts and such.
exec_in_erlang_default_shell(Cmd);
undefined ->
%% Exec called, but the a shell other than the default shell is defined.
%% No new exec shell is defined, so don't execute!
%% We don't know if it is intended to use the new shell or not.
{"Prohibited.", 255, 1};
_ ->
%% Exec called and a Fun or MFA is defined to use. The F communicates via
%% standard io:write/read.
%% Kept for compatibility.
S1 = start_exec_shell(ConnectionHandler, Cmd, S0),
ssh_connection:reply_request(ConnectionHandler, WantReply, success, ChannelId),
{ok, S1}
end
of
{Reply, Status, Type} ->
write_chars(ConnectionHandler, ChannelId, Type, Reply),
ssh_connection:reply_request(ConnectionHandler, WantReply, success, ChannelId),
ssh_connection:exit_status(ConnectionHandler, ChannelId, Status),
ssh_connection:send_eof(ConnectionHandler, ChannelId),
{stop, ChannelId, S0#state{channel = ChannelId, cm = ConnectionHandler}};
{ok, S} ->
{ok, S#state{channel = ChannelId,
cm = ConnectionHandler}}
end;
handle_ssh_msg({ssh_cm, _ConnectionHandler, {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, ConnectionHandler},
#state{channel = ChannelId,
cm = ConnectionHandler} = State) ->
{ok, State};
handle_msg({Group, set_unicode_state, _Arg}, State) ->
Group ! {self(), set_unicode_state, false},
{ok, State};
handle_msg({Group, get_unicode_state}, State) ->
Group ! {self(), get_unicode_state, false},
{ok, State};
handle_msg({Group, tty_geometry}, #state{group = Group,
pty = Pty
} = State) ->
case Pty of
#ssh_pty{width=Width,height=Height} ->
Group ! {self(),tty_geometry,{Width,Height}};
_ ->
%% This is a dirty fix of the problem with the otp ssh:shell
%% client. That client will not allocate a tty, but someone
%% asks for the tty_geometry just before every erlang prompt.
%% If that question is not answered, there is a 2 sec timeout
%% Until the prompt is seen by the user at the client side ...
Group ! {self(),tty_geometry,{0,0}}
end,
{ok,State};
handle_msg({Group, Req}, #state{group = Group, buf = Buf, pty = Pty,
cm = ConnectionHandler,
channel = ChannelId} = State) ->
{Chars, NewBuf} = io_request(Req, Buf, Pty, Group),
write_chars(ConnectionHandler, ChannelId, Chars),
{ok, State#state{buf = NewBuf}};
handle_msg({'EXIT', Group, Reason}, #state{group = Group,
cm = ConnectionHandler,
channel = ChannelId} = State) ->
Status = case Reason of
normal -> 0;
_ -> -1
end,
ssh_connection:exit_status(ConnectionHandler, ChannelId, Status),
ssh_connection:send_eof(ConnectionHandler, ChannelId),
{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
%%--------------------------------------------------------------------
to_group([], _Group) ->
ok;
to_group([$\^C | Tail], Group) ->
exit(Group, interrupt),
to_group(Tail, Group);
to_group(Data, Group) ->
Func = fun(C) -> C /= $\^C end,
Tail = case lists:splitwith(Func, Data) of
{[], Right} ->
Right;
{Left, Right} ->
Group ! {self(), {data, Left}},
Right
end,
to_group(Tail, Group).
%%--------------------------------------------------------------------
%%% 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, _Group) ->
window_change(Tty, OldTty, Buf);
io_request({put_chars, Cs}, Buf, Tty, _Group) ->
put_chars(bin_to_list(Cs), Buf, Tty);
io_request({put_chars, unicode, Cs}, Buf, Tty, _Group) ->
put_chars(unicode:characters_to_list(Cs,unicode), Buf, Tty);
io_request({insert_chars, Cs}, Buf, Tty, _Group) ->
insert_chars(bin_to_list(Cs), Buf, Tty);
io_request({insert_chars, unicode, Cs}, Buf, Tty, _Group) ->
insert_chars(unicode:characters_to_list(Cs,unicode), Buf, Tty);
io_request({move_rel, N}, Buf, Tty, _Group) ->
move_rel(N, Buf, Tty);
io_request({delete_chars,N}, Buf, Tty, _Group) ->
delete_chars(N, Buf, Tty);
io_request(beep, Buf, _Tty, _Group) ->
{[7], Buf};
%% New in R12
io_request({get_geometry,columns},Buf,Tty, _Group) ->
{ok, Tty#ssh_pty.width, Buf};
io_request({get_geometry,rows},Buf,Tty, _Group) ->
{ok, Tty#ssh_pty.height, Buf};
io_request({requests,Rs}, Buf, Tty, Group) ->
io_requests(Rs, Buf, Tty, [], Group);
io_request(tty_geometry, Buf, Tty, Group) ->
io_requests([{move_rel, 0}, {put_chars, unicode, [10]}],
Buf, Tty, [], Group);
%{[], Buf};
%% New in 18
io_request({put_chars_sync, Class, Cs, Reply}, Buf, Tty, Group) ->
%% We handle these asynchronous for now, if we need output guarantees
%% we have to handle these synchronously
Group ! {reply, Reply},
io_request({put_chars, Class, Cs}, Buf, Tty, Group);
io_request(_R, Buf, _Tty, _Group) ->
{[], Buf}.
io_requests([R|Rs], Buf, Tty, Acc, Group) ->
{Chars, NewBuf} = io_request(R, Buf, Tty, Group),
io_requests(Rs, NewBuf, Tty, [Acc|Chars], Group);
io_requests([], Buf, _Tty, Acc, _Group) ->
{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 = case Col + N of V when V >= 0 -> V; _ -> 0 end,
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(ConnectionHandler, ChannelId, Chars) ->
write_chars(ConnectionHandler, ChannelId, ?SSH_EXTENDED_DATA_DEFAULT, Chars).
write_chars(ConnectionHandler, ChannelId, Type, Chars) ->
case has_chars(Chars) of
false -> ok;
true -> ssh_connection:send(ConnectionHandler,
ChannelId,
Type,
Chars)
end.
has_chars([C|_]) when is_integer(C) -> true;
has_chars([H|T]) when is_list(H) ; is_binary(H) -> has_chars(H) orelse has_chars(T);
has_chars(<<_:8,_/binary>>) -> true;
has_chars(_) -> false.
%%% 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(ConnectionHandler, State) ->
ShellSpawner =
case State#state.shell of
Shell when is_function(Shell, 1) ->
[{user,User}] = ssh_connection_handler:connection_info(ConnectionHandler, [user]),
fun() -> Shell(User) end;
Shell when is_function(Shell, 2) ->
ConnectionInfo =
ssh_connection_handler:connection_info(ConnectionHandler, [peer, user]),
User = proplists:get_value(user, ConnectionInfo),
{_, PeerAddr} = proplists:get_value(peer, ConnectionInfo),
fun() -> Shell(User, PeerAddr) end;
{_,_,_} = Shell ->
Shell
end,
State#state{group = group:start(self(), ShellSpawner, [{echo, get_echo(State#state.pty)}]),
buf = empty_buf()}.
%%--------------------------------------------------------------------
start_exec_shell(ConnectionHandler, Cmd, State) ->
ExecShellSpawner =
case State#state.exec of
ExecShell when is_function(ExecShell, 1) ->
fun() -> ExecShell(Cmd) end;
ExecShell when is_function(ExecShell, 2) ->
[{user,User}] = ssh_connection_handler:connection_info(ConnectionHandler, [user]),
fun() -> ExecShell(Cmd, User) end;
ExecShell when is_function(ExecShell, 3) ->
ConnectionInfo =
ssh_connection_handler:connection_info(ConnectionHandler, [peer, user]),
User = proplists:get_value(user, ConnectionInfo),
{_, PeerAddr} = proplists:get_value(peer, ConnectionInfo),
fun() -> ExecShell(Cmd, User, PeerAddr) end;
{M,F,A} ->
{M, F, A++[Cmd]}
end,
State#state{group = group:start(self(), ExecShellSpawner, [{echo,false}]),
buf = empty_buf()}.
%%--------------------------------------------------------------------
exec_in_erlang_default_shell(Cmd) ->
case eval(parse(scan(Cmd))) of
{ok, Term} ->
{io_lib:format("~p\n", [Term]), 0, 0};
{error, Error} when is_atom(Error) ->
{io_lib:format("Error in ~p: ~p\n", [Cmd,Error]), -1, 1};
_ ->
{io_lib:format("Error: ~p\n", [Cmd]), -1, 1}
end.
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} ->
{ok, Value};
{'EXIT', {Error, _}} ->
{error, Error};
{error, Error} ->
{error, Error};
Error ->
{error, Error}
end;
eval({error,Error}) ->
{error, Error};
eval(Error) ->
{error, Error}.
%%--------------------------------------------------------------------
exec_direct(ConnectionHandler, ExecSpec, Cmd) ->
try
case ExecSpec of
_ when is_function(ExecSpec, 1) ->
ExecSpec(Cmd);
_ when is_function(ExecSpec, 2) ->
[{user,User}] = ssh_connection_handler:connection_info(ConnectionHandler, [user]),
ExecSpec(Cmd, User);
_ when is_function(ExecSpec, 3) ->
ConnectionInfo =
ssh_connection_handler:connection_info(ConnectionHandler, [peer, user]),
User = proplists:get_value(user, ConnectionInfo),
{_, PeerAddr} = proplists:get_value(peer, ConnectionInfo),
ExecSpec(Cmd, User, PeerAddr)
end
of
Reply ->
return_direct_exec_reply(Reply, Cmd)
catch
C:Error ->
{io_lib:format("Error in \"~s\": ~p ~p~n", [Cmd,C,Error]), -1, 1}
end.
return_direct_exec_reply(Reply, Cmd) ->
case fmt_exec_repl(Reply) of
{ok,S} ->
{S, 0, 0};
{error,S} ->
{io_lib:format("Error in \"~s\": ~s~n", [Cmd,S]), -1, 1}
end.
fmt_exec_repl({T,A}) when T==ok ; T==error ->
try
{T, io_lib:format("~s",[A])}
catch
error:badarg ->
{T, io_lib:format("~p", [A])};
C:Err ->
{error, io_lib:format("~p:~p~n",[C,Err])}
end;
fmt_exec_repl(Other) ->
{error, io_lib:format("Bad exec-plugin return: ~p",[Other])}.
%%--------------------------------------------------------------------
% 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.
%%%################################################################
%%%#
%%%# Tracing
%%%#
dbg_trace(points, _, _) -> [terminate];
dbg_trace(flags, terminate, _) -> [c];
dbg_trace(on, terminate, _) -> dbg:tp(?MODULE, terminate, 2, x);
dbg_trace(off, terminate, _) -> dbg:ctpg(?MODULE, terminate, 2);
dbg_trace(format, terminate, {call, {?MODULE,terminate, [Reason, State]}}) ->
["Cli Terminating:\n",
io_lib:format("Reason: ~p,~nState:~n~s", [Reason, wr_record(State)])
].
?wr_record(state).
