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| var inherits = require('util').inherits;
var DuplexStream = require('stream').Duplex;
var ReadableStream = require('stream').Readable;
var WritableStream = require('stream').Writable;
var STDERR = require('ssh2-streams').constants.CHANNEL_EXTENDED_DATATYPE.STDERR;
var PACKET_SIZE = 32 * 1024;
var MAX_WINDOW = 1 * 1024 * 1024;
var WINDOW_THRESHOLD = MAX_WINDOW / 2;
var CUSTOM_EVENTS = [
'CHANNEL_EOF',
'CHANNEL_CLOSE',
'CHANNEL_DATA',
'CHANNEL_EXTENDED_DATA',
'CHANNEL_WINDOW_ADJUST',
'CHANNEL_SUCCESS',
'CHANNEL_FAILURE',
'CHANNEL_REQUEST'
];
var CUSTOM_EVENTS_LEN = CUSTOM_EVENTS.length;
function Channel(info, client, opts) {
var streamOpts = {
highWaterMark: MAX_WINDOW,
allowHalfOpen: (!opts || (opts && opts.allowHalfOpen !== false))
};
this.allowHalfOpen = streamOpts.allowHalfOpen;
DuplexStream.call(this, streamOpts);
var self = this;
var server = opts && opts.server;
this.server = server;
this.type = info.type;
this.subtype = undefined;
/*
incoming and outgoing contain these properties:
{
id: undefined,
window: undefined,
packetSize: undefined,
state: 'closed'
}
*/
var incoming = this.incoming = info.incoming;
var incomingId = incoming.id;
var outgoing = this.outgoing = info.outgoing;
var callbacks = this._callbacks = [];
var exitCode;
var exitSignal;
var exitDump;
var exitDesc;
var exitLang;
this._client = client;
this._hasX11 = false;
var channels = client._channels;
var sshstream = client._sshstream;
function ondrain() {
if (self._waitClientDrain) {
self._waitClientDrain = false;
if (!self._waitWindow) {
if (self._chunk)
self._write(self._chunk, null, self._chunkcb);
else if (self._chunkcb)
self._chunkcb();
else if (self._chunkErr)
self.stderr._write(self._chunkErr, null, self._chunkcbErr);
else if (self._chunkcbErr)
self._chunkcbErr();
}
}
}
client._sock.on('drain', ondrain);
sshstream.once('CHANNEL_EOF:' + incomingId, function() {
if (incoming.state === 'closed' || incoming.state === 'eof')
return;
incoming.state = 'eof';
if (self.readable)
self.push(null);
if (!server && self.stderr.readable)
self.stderr.push(null);
}).once('CHANNEL_CLOSE:' + incomingId, function() {
if (incoming.state === 'closed')
return;
incoming.state = 'closed';
if (self.readable)
self.push(null);
if (server && self.stderr.writable)
self.stderr.end();
else if (!server && self.stderr.readable)
self.stderr.push(null);
if (outgoing.state === 'open' || outgoing.state === 'eof')
self.close();
if (outgoing.state === 'closing')
outgoing.state = 'closed';
delete channels[incomingId];
var state = self._writableState;
client._sock.removeListener('drain', ondrain);
if (!state.ending && !state.finished)
self.end();
// Take care of any outstanding channel requests
self._callbacks = [];
for (var i = 0; i < callbacks.length; ++i)
callbacks[i](true);
callbacks = self._callbacks;
if (!server) {
// align more with node child processes, where the close event gets the
// same arguments as the exit event
if (!self.readable) {
if (exitCode === null) {
self.emit('close', exitCode, exitSignal, exitDump, exitDesc,
exitLang);
} else
self.emit('close', exitCode);
} else {
self.once('end', function() {
if (exitCode === null) {
self.emit('close', exitCode, exitSignal, exitDump, exitDesc,
exitLang);
} else
self.emit('close', exitCode);
});
}
if (!self.stderr.readable)
self.stderr.emit('close');
else {
self.stderr.once('end', function() {
self.stderr.emit('close');
});
}
} else { // Server mode
if (!self.readable)
self.emit('close');
else {
self.once('end', function() {
self.emit('close');
});
}
}
for (var i = 0; i < CUSTOM_EVENTS_LEN; ++i)
sshstream.removeAllListeners(CUSTOM_EVENTS[i] + ':' + incomingId);
}).on('CHANNEL_DATA:' + incomingId, function(data) {
// the remote party should not be sending us data if there is no window
// space available ...
if (incoming.window === 0)
return;
incoming.window -= data.length;
if (!self.push(data)) {
self._waitChanDrain = true;
return;
}
if (incoming.window <= WINDOW_THRESHOLD)
windowAdjust(self);
}).on('CHANNEL_WINDOW_ADJUST:' + incomingId, function(amt) {
// the server is allowing us to send `amt` more bytes of data
outgoing.window += amt;
if (self._waitWindow) {
self._waitWindow = false;
if (!self._waitClientDrain) {
if (self._chunk)
self._write(self._chunk, null, self._chunkcb);
else if (self._chunkcb)
self._chunkcb();
else if (self._chunkErr)
self.stderr._write(self._chunkErr, null, self._chunkcbErr);
else if (self._chunkcbErr)
self._chunkcbErr();
}
}
}).on('CHANNEL_SUCCESS:' + incomingId, function() {
if (server) {
sshstream._kalast = Date.now();
sshstream._kacnt = 0;
} else
client._resetKA();
if (callbacks.length)
callbacks.shift()(false);
}).on('CHANNEL_FAILURE:' + incomingId, function() {
if (server) {
sshstream._kalast = Date.now();
sshstream._kacnt = 0;
} else
client._resetKA();
if (callbacks.length)
callbacks.shift()(true);
}).on('CHANNEL_REQUEST:' + incomingId, function(info) {
if (!server) {
if (info.request === 'exit-status') {
self.emit('exit', exitCode = info.code);
return;
} else if (info.request === 'exit-signal') {
self.emit('exit',
exitCode = null,
exitSignal = 'SIG' + info.signal,
exitDump = info.coredump,
exitDesc = info.description,
exitLang = info.lang);
return;
}
}
// keepalive request? OpenSSH will send one as a channel request if there
// is a channel open
if (info.wantReply)
sshstream.channelFailure(outgoing.id);
});
this.stdin = this.stdout = this;
if (server)
this.stderr = new ServerStderr(this);
else {
this.stderr = new ReadableStream(streamOpts);
this.stderr._read = function(n) {
if (self._waitChanDrain) {
self._waitChanDrain = false;
if (incoming.window <= WINDOW_THRESHOLD)
windowAdjust(self);
}
};
sshstream.on('CHANNEL_EXTENDED_DATA:' + incomingId,
function(type, data) {
// the remote party should not be sending us data if there is no window
// space available ...
if (incoming.window === 0)
return;
incoming.window -= data.length;
if (!self.stderr.push(data)) {
self._waitChanDrain = true;
return;
}
if (incoming.window <= WINDOW_THRESHOLD)
windowAdjust(self);
}
);
}
// outgoing data
this._waitClientDrain = false; // Client stream-level backpressure
this._waitWindow = false; // SSH-level backpressure
// incoming data
this._waitChanDrain = false; // Channel Readable side backpressure
this._chunk = undefined;
this._chunkcb = undefined;
this._chunkErr = undefined;
this._chunkcbErr = undefined;
function onFinish() {
self.eof();
if (server || (!server && !self.allowHalfOpen))
self.close();
self.writable = false;
}
this.on('finish', onFinish)
.on('prefinish', onFinish); // for node v0.11+
function onEnd() {
self.readable = false;
}
this.on('end', onEnd)
.on('close', onEnd);
}
inherits(Channel, DuplexStream);
Channel.prototype.eof = function() {
var ret = true;
var outgoing = this.outgoing;
if (outgoing.state === 'open') {
outgoing.state = 'eof';
ret = this._client._sshstream.channelEOF(outgoing.id);
}
return ret;
};
Channel.prototype.close = function() {
var ret = true;
var outgoing = this.outgoing;
if (outgoing.state === 'open' || outgoing.state === 'eof') {
outgoing.state = 'closing';
ret = this._client._sshstream.channelClose(outgoing.id);
}
return ret;
};
Channel.prototype._read = function(n) {
if (this._waitChanDrain) {
this._waitChanDrain = false;
if (this.incoming.window <= WINDOW_THRESHOLD)
windowAdjust(this);
}
};
Channel.prototype._write = function(data, encoding, cb) {
var sshstream = this._client._sshstream;
var outgoing = this.outgoing;
var packetSize = outgoing.packetSize;
var id = outgoing.id;
var window = outgoing.window;
var len = data.length;
var p = 0;
var ret;
var buf;
var sliceLen;
if (outgoing.state !== 'open')
return;
while (len - p > 0 && window > 0) {
sliceLen = len - p;
if (sliceLen > window)
sliceLen = window;
if (sliceLen > packetSize)
sliceLen = packetSize;
ret = sshstream.channelData(id, data.slice(p, p + sliceLen));
p += sliceLen;
window -= sliceLen;
if (!ret) {
this._waitClientDrain = true;
this._chunk = undefined;
this._chunkcb = cb;
break;
}
}
outgoing.window = window;
if (len - p > 0) {
if (window === 0)
this._waitWindow = true;
if (p > 0) {
// partial
buf = new Buffer(len - p);
data.copy(buf, 0, p);
this._chunk = buf;
} else
this._chunk = data;
this._chunkcb = cb;
return;
}
if (!this._waitClientDrain)
cb();
};
Channel.prototype.destroy = function() {
this.end();
};
// session type-specific methods
Channel.prototype.setWindow = function(rows, cols, height, width) {
if (this.server)
throw new Error('Client-only method called in server mode');
if (this.type === 'session'
&& (this.subtype === 'shell' || this.subtype === 'exec')
&& this.writable
&& this.outgoing.state === 'open') {
return this._client._sshstream.windowChange(this.outgoing.id,
rows,
cols,
height,
width);
}
return true;
};
Channel.prototype.signal = function(signalName) {
if (this.server)
throw new Error('Client-only method called in server mode');
if (this.type === 'session'
&& this.writable
&& this.outgoing.state === 'open')
return this._client._sshstream.signal(this.outgoing.id, signalName);
return true;
};
Channel.prototype.exit = function(name, coreDumped, msg) {
if (!this.server)
throw new Error('Server-only method called in client mode');
if (this.type === 'session'
&& this.writable
&& this.outgoing.state === 'open') {
if (typeof name === 'number')
return this._client._sshstream.exitStatus(this.outgoing.id, name);
else {
return this._client._sshstream.exitSignal(this.outgoing.id,
name,
coreDumped,
msg);
}
}
return true;
};
Channel.MAX_WINDOW = MAX_WINDOW;
Channel.PACKET_SIZE = PACKET_SIZE;
function windowAdjust(self) {
if (self.outgoing.state !== 'open')
return true;
var amt = MAX_WINDOW - self.incoming.window;
if (amt <= 0)
return true;
self.incoming.window += amt;
return self._client._sshstream.channelWindowAdjust(self.outgoing.id, amt);
}
function ServerStderr(channel) {
WritableStream.call(this, { highWaterMark: MAX_WINDOW });
this._channel = channel;
}
inherits(ServerStderr, WritableStream);
ServerStderr.prototype._write = function(data, encoding, cb) {
var channel = this._channel;
var sshstream = channel._client._sshstream;
var outgoing = channel.outgoing;
var packetSize = outgoing.packetSize;
var id = outgoing.id;
var window = outgoing.window;
var len = data.length;
var p = 0;
var ret;
var buf;
var sliceLen;
if (channel.outgoing.state !== 'open')
return;
while (len - p > 0 && window > 0) {
sliceLen = len - p;
if (sliceLen > window)
sliceLen = window;
if (sliceLen > packetSize)
sliceLen = packetSize;
ret = sshstream.channelExtData(id, data.slice(p, p + sliceLen), STDERR);
p += sliceLen;
window -= sliceLen;
if (!ret) {
channel._waitClientDrain = true;
channel._chunkErr = undefined;
channel._chunkcbErr = cb;
break;
}
}
outgoing.window = window;
if (len - p > 0) {
if (window === 0)
channel._waitWindow = true;
if (p > 0) {
// partial
buf = new Buffer(len - p);
data.copy(buf, 0, p);
channel._chunkErr = buf;
} else
channel._chunkErr = data;
channel._chunkcbErr = cb;
return;
}
if (!channel._waitClientDrain)
cb();
};
module.exports = Channel;
|