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%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2008-2018. 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%
%%
%%
%%----------------------------------------------------------------------
%% Purpose: Ssh channel supervisor.
%%----------------------------------------------------------------------
-module(ssh_channel_sup).
-behaviour(supervisor).
-include("ssh.hrl").
-export([start_link/1, start_child/8]).
%% Supervisor callback
-export([init/1]).
%%%=========================================================================
%%% Internal API
%%%=========================================================================
start_link(Args) ->
supervisor:start_link(?MODULE, [Args]).
start_child(client, ChannelSup, ConnRef, Callback, Id, Args, Exec, _Opts) when is_pid(ConnRef) ->
start_the_channel(ssh_client_channel, ChannelSup, ConnRef, Callback, Id, Args, Exec);
start_child(server, ChannelSup, ConnRef, Callback, Id, Args, Exec, Opts) when is_pid(ConnRef) ->
case max_num_channels_not_exceeded(ChannelSup, Opts) of
true ->
start_the_channel(ssh_server_channel, ChannelSup, ConnRef, Callback, Id, Args, Exec);
false ->
{error, max_num_channels_exceeded}
end.
%%%=========================================================================
%%% Supervisor callback
%%%=========================================================================
init(_Args) ->
RestartStrategy = one_for_one,
MaxR = 10,
MaxT = 3600,
Children = [],
{ok, {{RestartStrategy, MaxR, MaxT}, Children}}.
%%%=========================================================================
%%% Internal functions
%%%=========================================================================
max_num_channels_not_exceeded(ChannelSup, Opts) ->
MaxNumChannels = ?GET_OPT(max_channels, Opts),
NumChannels = length([x || {_,_,worker,[ssh_server_channel]} <-
supervisor:which_children(ChannelSup)]),
%% Note that NumChannels is BEFORE starting a new one
NumChannels < MaxNumChannels.
start_the_channel(ChanMod, ChannelSup, ConnRef, Callback, Id, Args, Exec) ->
ChildSpec =
#{id => make_ref(),
start => {ChanMod, start_link, [ConnRef, Id, Callback, Args, Exec]},
restart => temporary,
type => worker,
modules => [ChanMod]
},
case supervisor:start_child(ChannelSup, ChildSpec) of
{ok, Pid} -> {ok, Pid};
{ok, Pid, _Info} -> {ok, Pid};
{error, {Error,_Info}} -> {error, Error};
{error, Error} -> {error, Error}
end.
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