This module provides API functions to send SSH Connection Protocol events to the other side of an SSH channel.
Type definitions that are used more than once in this module, or abstractions to indicate the intended use of the data type, or both:
adjust_window(ConnectionRef, ChannelId, NumOfBytes) -> ok
Types
Adjusts the SSH flow control window. This is to be done by both the client- and server-side channel processes.
Note
Channels implemented with the ssh_client_channel
behavior do not normally need to call this function as flow control is handled by the behavior. The behavior adjusts the window every time the callback handle_ssh_msg/2
returns after processing channel data.
close(ConnectionRef, ChannelId) -> ok
Types
A server- or client-channel process can choose to close their session by sending a close event.
Note
This function is called by the ssh_client_channel
behavior when the channel is terminated, see ssh_client_channel(3)
. Thus, channels implemented with the behavior are not to call this function explicitly.
exec(ConnectionRef, ChannelId, Command, TimeOut) -> ssh_request_status() | {error, reason()}
Types
Is to be called by a client-channel process to request that the server starts executing the given command. The result is several messages according to the following pattern. The last message is a channel close message, as the exec
request is a one-time execution that closes the channel when it is done.
N x {ssh_cm, connection_ref(), {data, channel_id(), ssh_data_type_code(), Data :: binary()}}
The result of executing the command can be only one line or thousands of lines depending on the command.
0 or 1 x {ssh_cm, connection_ref(), {eof, channel_id()}}
Indicates that no more data is to be sent.
0 or 1 x {ssh_cm, connection_ref(), {exit_signal, channel_id(), ExitSignal :: string(), ErrorMsg :: string(), LanguageString :: string()}}
Not all systems send signals. For details on valid string values, see RFC 4254, Section 6.10
0 or 1 x {ssh_cm, connection_ref(), {exit_status, channel_id(), ExitStatus :: integer()}}
It is recommended by the SSH Connection Protocol to send this message, but that is not always the case.
1 x {ssh_cm, connection_ref(), {closed, channel_id()}}
Indicates that the ssh_client_channel
started for the execution of the command has now been shut down.
exit_status(ConnectionRef, ChannelId, Status) -> ok
Types
Is to be called by a server-channel process to send the exit status of a command to the client.
ptty_alloc(ConnectionRef, ChannelId, Options) ->
ptty_alloc(ConnectionRef, ChannelId, Options, Timeout) -> > ssh_request_status() | {error, reason()}
Types
Sends an SSH Connection Protocol pty_req
, to allocate a pseudo-terminal. Is to be called by an SSH client process.
Options:
- {term, string()}
Defaults to os:getenv("TERM") or vt100 if it is undefined.
- {width, integer()}
Defaults to 80 if pixel_width
is not defined.
- {height, integer()}
Defaults to 24 if pixel_height
is not defined.
- {pixel_width, integer()}
Is disregarded if width
is defined.
- {pixel_height, integer()}
Is disregarded if height
is defined.
- {pty_opts, [{posix_atom(), integer()}]}
-
Option can be an empty list. Otherwise, see possible POSIX names in Section 8 in RFC 4254
.
reply_request(ConnectionRef, WantReply, Status, ChannelId) -> ok
Types
Sends status replies to requests where the requester has stated that it wants a status report, that is, WantReply = true
. If WantReply
is false
, calling this function becomes a "noop". Is to be called while handling an SSH Connection Protocol message containing a WantReply
boolean value.
send(ConnectionRef, ChannelId, Data) ->
send(ConnectionRef, ChannelId, Data, Timeout) ->
send(ConnectionRef, ChannelId, Type, Data) ->
send(ConnectionRef, ChannelId, Type, Data, TimeOut) -> ok | {error, timeout} | {error, closed}
Types
Is to be called by client- and server-channel processes to send data to each other.
The function subsystem/4
and subsequent calls of send/3,4,5
must be executed in the same process.
send_eof(ConnectionRef, ChannelId) -> ok | {error, closed}
Types
Sends EOF on channel ChannelId
.
session_channel(ConnectionRef, Timeout) ->
session_channel(ConnectionRef, InitialWindowSize, MaxPacketSize, Timeout) -> {ok, channel_id()} | {error, reason()}
Types
Opens a channel for an SSH session. The channel id returned from this function is the id used as input to the other functions in this module.
setenv(ConnectionRef, ChannelId, Var, Value, TimeOut) -> ssh_request_status() | {error, reason()}
Types
Environment variables can be passed before starting the shell/command. Is to be called by a client channel processes.
shell(ConnectionRef, ChannelId) -> ok | failure | {error, closed}
Types
Is to be called by a client channel process to request that the user default shell (typically defined in /etc/passwd in Unix systems) is executed at the server end.
Note: the return value is ok
instead of success
unlike in other functions in this module. This is a fault that was introduced so long ago that any change would break a large number of existing software.
subsystem(ConnectionRef, ChannelId, Subsystem, Timeout) -> ssh_request_status() | {error, reason()}
Types
Is to be called by a client-channel process for requesting to execute a predefined subsystem on the server.
The function subsystem/4
and subsequent calls of send/3,4,5
must be executed in the same process.