File 2399-ssh-Simplification-of-using-fun-s-as-exec-subsystems.patch of Package erlang
From 4eb60b4d23befd64250b8aca456f082e5d212878 Mon Sep 17 00:00:00 2001
From: Hans Nilsson <hans@erlang.org>
Date: Fri, 2 Mar 2018 18:02:48 +0100
Subject: [PATCH 1/2] ssh: Simplification of using fun:s as exec subsystems
---
lib/ssh/src/ssh_cli.erl | 270 +++++++++++++++++++++-------------
lib/ssh/src/ssh_options.erl | 8 +-
3 files changed, 255 insertions(+), 127 deletions(-)
diff --git a/lib/ssh/src/ssh_cli.erl b/lib/ssh/src/ssh_cli.erl
index 958c342f5f..783f2f80c0 100644
--- a/lib/ssh/src/ssh_cli.erl
+++ b/lib/ssh/src/ssh_cli.erl
@@ -118,42 +118,53 @@ handle_ssh_msg({ssh_cm, ConnectionHandler,
write_chars(ConnectionHandler, ChannelId, Chars),
{ok, State#state{pty = Pty, buf = NewBuf}};
-handle_ssh_msg({ssh_cm, ConnectionHandler,
- {shell, ChannelId, WantReply}}, State) ->
+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}}, #state{exec=undefined,
- shell=?DEFAULT_SHELL} = State) ->
- {Reply, Status} = exec(Cmd),
- write_chars(ConnectionHandler,
- ChannelId, io_lib:format("~p\n", [Reply])),
- ssh_connection:reply_request(ConnectionHandler, WantReply,
- success, ChannelId),
- ssh_connection:exit_status(ConnectionHandler, ChannelId, Status),
- ssh_connection:send_eof(ConnectionHandler, ChannelId),
- {stop, ChannelId, State#state{channel = ChannelId, cm = ConnectionHandler}};
-
-handle_ssh_msg({ssh_cm, ConnectionHandler,
- {exec, ChannelId, WantReply, _Cmd}}, #state{exec = undefined} = State) ->
- write_chars(ConnectionHandler, ChannelId, 1, "Prohibited.\n"),
ssh_connection:reply_request(ConnectionHandler, WantReply, success, ChannelId),
- ssh_connection:exit_status(ConnectionHandler, ChannelId, 255),
- ssh_connection:send_eof(ConnectionHandler, ChannelId),
- {stop, ChannelId, State#state{channel = ChannelId, cm = ConnectionHandler}};
-
-handle_ssh_msg({ssh_cm, ConnectionHandler,
- {exec, ChannelId, WantReply, Cmd}}, State) ->
- NewState = start_shell(ConnectionHandler, Cmd, 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};
@@ -259,35 +270,7 @@ to_group(Data, Group) ->
end,
to_group(Tail, Group).
-exec(Cmd) ->
- case eval(parse(scan(Cmd))) of
- {error, _} ->
- {Cmd, 0}; %% This should be an external call
- Term ->
- Term
- 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} ->
- {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
@@ -506,53 +489,130 @@ bin_to_list(L) when is_list(L) ->
bin_to_list(I) when is_integer(I) ->
I.
+
+%%--------------------------------------------------------------------
start_shell(ConnectionHandler, State) ->
- Shell = State#state.shell,
- ConnectionInfo = ssh_connection_handler:connection_info(ConnectionHandler,
- [peer, user]),
- ShellFun = case is_function(Shell) of
- true ->
- User = proplists:get_value(user, ConnectionInfo),
- case erlang:fun_info(Shell, arity) of
- {arity, 1} ->
- fun() -> Shell(User) end;
- {arity, 2} ->
- {_, PeerAddr} = proplists:get_value(peer, ConnectionInfo),
- 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(_ConnectionHandler, 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(ConnectionHandler, Cmd, #state{exec=Shell} = State) when is_function(Shell) ->
-
- ConnectionInfo = ssh_connection_handler:connection_info(ConnectionHandler,
- [peer, user]),
- User = proplists:get_value(user, ConnectionInfo),
- ShellFun =
- case erlang:fun_info(Shell, arity) of
- {arity, 1} ->
- fun() -> Shell(Cmd) end;
- {arity, 2} ->
- fun() -> Shell(Cmd, User) end;
- {arity, 3} ->
- {_, PeerAddr} = proplists:get_value(peer, ConnectionInfo),
- 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()}.
+ 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) ->
diff --git a/lib/ssh/src/ssh_options.erl b/lib/ssh/src/ssh_options.erl
index 1e10f72956..c05293d1ae 100644
--- a/lib/ssh/src/ssh_options.erl
+++ b/lib/ssh/src/ssh_options.erl
@@ -275,10 +275,12 @@ default(server) ->
class => user_options
},
- {exec, def} => % FIXME: need some archeology....
+ {exec, def} =>
#{default => undefined,
- chk => fun({M,F,_}) -> is_atom(M) andalso is_atom(F);
- (V) -> is_function(V)
+ chk => fun({direct, V}) -> check_function1(V) orelse check_function2(V) orelse check_function3(V);
+ %% Compatibility (undocumented):
+ ({M,F,A}) -> is_atom(M) andalso is_atom(F) andalso is_list(A);
+ (V) -> check_function1(V) orelse check_function2(V) orelse check_function3(V)
end,
class => user_options
},
--
2.16.3
