From 75ca7672b5c7bb07196a3a2b294157479ff4f00a Mon Sep 17 00:00:00 2001
From: Ingela Anderton Andin <ingela@erlang.org>
Date: Mon, 15 Dec 2014 09:54:26 +0100
Subject: ssh: Improve errorhandling in ssh_connection.erl

If a channel is closed by the peer while using a function with call semantics
in ssh_connection.erl return {error, closed}. Document that the functions
can return {error, timeout | closed} and not only ssh_request_status()
---
 lib/ssh/src/ssh_connection.erl         | 22 ++++++++++++++--------
 lib/ssh/src/ssh_connection_handler.erl | 15 ++++++++++++---
 2 files changed, 26 insertions(+), 11 deletions(-)

(limited to 'lib/ssh/src')

diff --git a/lib/ssh/src/ssh_connection.erl b/lib/ssh/src/ssh_connection.erl
index 01141622d6..c66f810948 100644
--- a/lib/ssh/src/ssh_connection.erl
+++ b/lib/ssh/src/ssh_connection.erl
@@ -56,8 +56,8 @@
 %%--------------------------------------------------------------------
 
 %%--------------------------------------------------------------------
--spec session_channel(pid(), timeout()) -> {ok, channel_id()} | {error, term()}.
--spec session_channel(pid(), integer(), integer(), timeout()) -> {ok, channel_id()} | {error, term()}.
+-spec session_channel(pid(), timeout()) -> {ok, channel_id()} | {error, timeout | closed}.
+-spec session_channel(pid(), integer(), integer(), timeout()) -> {ok, channel_id()} | {error, timeout | closed}.
 
 %% Description: Opens a channel for a ssh session. A session is a
 %% remote execution of a program. The program may be a shell, an
@@ -81,7 +81,8 @@ session_channel(ConnectionHandler, InitialWindowSize,
     end.
 
 %%--------------------------------------------------------------------
--spec exec(pid(), channel_id(), string(), timeout()) -> success | failure.
+-spec exec(pid(), channel_id(), string(), timeout()) -> 
+		  success | failure | {error, timeout | closed}.
 
 %% Description: Will request that the server start the
 %% execution of the given command. 
@@ -101,8 +102,8 @@ shell(ConnectionHandler, ChannelId) ->
     ssh_connection_handler:request(ConnectionHandler, self(), ChannelId,
  				   "shell", false, <<>>, 0).
 %%--------------------------------------------------------------------
--spec subsystem(pid(), channel_id(), string(), timeout()) ->
-		       success | failure | {error, timeout}.
+-spec subsystem(pid(), channel_id(), string(), timeout()) -> 
+		       success | failure | {error, timeout | closed}.
 %%
 %% Description: Executes a predefined subsystem.
 %%--------------------------------------------------------------------
@@ -142,7 +143,7 @@ send_eof(ConnectionHandler, Channel) ->
     ssh_connection_handler:send_eof(ConnectionHandler, Channel).
 
 %%--------------------------------------------------------------------
--spec adjust_window(pid(), channel_id(), integer()) -> ok.
+-spec adjust_window(pid(), channel_id(), integer()) -> ok |  {error, closed}.
 %%
 %%
 %% Description: Adjusts the ssh flowcontrol window.
@@ -151,7 +152,8 @@ adjust_window(ConnectionHandler, Channel, Bytes) ->
     ssh_connection_handler:adjust_window(ConnectionHandler, Channel, Bytes).
 
 %%--------------------------------------------------------------------
--spec setenv(pid(), channel_id(), string(), string(), timeout()) ->  success | failure.
+-spec setenv(pid(), channel_id(), string(), string(), timeout()) ->  
+		    success | failure | {error, timeout | closed}.
 %%
 %%
 %% Description: Environment variables may be passed to the shell/command to be
@@ -183,7 +185,11 @@ reply_request(_,false, _, _) ->
     ok.
 
 %%--------------------------------------------------------------------
--spec ptty_alloc(pid(), channel_id(), proplists:proplist()) -> success | failiure.
+-spec ptty_alloc(pid(), channel_id(), proplists:proplist()) -> 
+			success | failiure | {error, closed}.
+-spec ptty_alloc(pid(), channel_id(), proplists:proplist(), timeout()) -> 
+			success | failiure | {error, timeout} | {error, closed}.
+
 %%
 %%
 %% Description: Sends a ssh connection protocol pty_req.
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index fdb9d3b3e6..915060c426 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -289,8 +289,13 @@ renegotiate_data(ConnectionHandler) ->
 -spec close(pid(), channel_id()) -> ok.
 %%--------------------------------------------------------------------
 close(ConnectionHandler, ChannelId) ->
-    sync_send_all_state_event(ConnectionHandler, {close, ChannelId}).
-
+    case sync_send_all_state_event(ConnectionHandler, {close, ChannelId}) of
+	ok ->
+	    ok;
+	{error, closed} -> 
+	    ok
+    end.	
+	
 %%--------------------------------------------------------------------
 -spec stop(pid()) -> ok | {error, term()}.
 %%--------------------------------------------------------------------
@@ -1204,7 +1209,11 @@ sync_send_all_state_event(FsmPid, Event) ->
     sync_send_all_state_event(FsmPid, Event, infinity).
 
 sync_send_all_state_event(FsmPid, Event, Timeout) ->
-    try gen_fsm:sync_send_all_state_event(FsmPid, Event, Timeout)
+    try gen_fsm:sync_send_all_state_event(FsmPid, Event, Timeout) of
+	{closed, _Channel} ->
+	    {error, closed};
+	Result ->
+	    Result
     catch
 	exit:{noproc, _} ->
 	    {error, closed};
-- 
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