Merge branch 'ia/ssh/add_users_guide/OTP-7786'

* ia/ssh/add_users_guide/OTP-7786:
  ssh: Document and clean up SSH behaviours
  ssh: Add Users Guide and enhance man pages
  ssh: Added User's Guide framework and minor enhancements

1 files changed, 47 insertions, 0 deletions

diff --git a/lib/ssh/src/ssh_subsystem.erl b/lib/ssh/src/ssh_subsystem.erl
new file mode 100644
index 0000000000..5a9fa32668
--- /dev/null
+++ b/lib/ssh/src/ssh_subsystem.erl
@@ -0,0 +1,47 @@
+-module(ssh_subsystem).
+
+%% API to special server side channel that can be pluged into the erlang ssh daemeon
+-callback init(Args :: term()) ->
+    {ok, State :: term()} | {ok, State :: term(), timeout() | hibernate} |
+    {stop, Reason :: term()} | ignore.
+
+-callback terminate(Reason :: (normal | shutdown | {shutdown, term()} |
+                               term()),
+                    State :: term()) ->
+    term().
+
+-callback handle_msg(Msg ::term(), State :: term()) ->
+    {noreply, NewState :: term()} |
+    {noreply, NewState :: term(), timeout() | hibernate} |
+    {stop, Reason :: term(), NewState :: term()}.
+
+-callback handle_ssh_msg({ssh_cm, ConnectionRef::term(), SshMsg::term()},
+			 State::term()) -> {ok, State::term()} |
+					   {stop, ChannelId::integer(),
+					    State::term()}.
+
+%%% API
+-export([start/4, start/5, start_link/4, start_link/5, enter_loop/1]).
+
+%% gen_server callbacks
+-export([init/1, terminate/2]).
+
+start(ConnectionManager, ChannelId, CallBack, CbInitArgs) ->
+    ssh_channel:start(ConnectionManager, ChannelId, CallBack, CbInitArgs, undefined).
+
+start(ConnectionManager, ChannelId, CallBack, CbInitArgs, Exec) ->
+    ssh_channel:start(ConnectionManager, ChannelId, CallBack, CbInitArgs, Exec).
+
+start_link(ConnectionManager, ChannelId, CallBack, CbInitArgs) ->
+    ssh_channel:start_link(ConnectionManager, ChannelId, CallBack, CbInitArgs, undefined).
+
+start_link(ConnectionManager, ChannelId, CallBack, CbInitArgs, Exec) ->
+    ssh_channel:start_link(ConnectionManager, ChannelId, CallBack, CbInitArgs, Exec).
+
+enter_loop(State) ->
+    ssh_channel:enter_loop(State).
+
+init(Args) ->
+    ssh_channel:init(Args).
+terminate(Reason, State) ->
+    ssh_channel:terminate(Reason, State).