Initial commit

server/node_modules/ssh2/lib/Channel.js

@@ -0,0 +1,295 @@
+'use strict';
+
+const {
+  Duplex: DuplexStream,
+  Readable: ReadableStream,
+  Writable: WritableStream,
+} = require('stream');
+
+const {
+  CHANNEL_EXTENDED_DATATYPE: { STDERR },
+} = require('./protocol/constants.js');
+const { bufferSlice } = require('./protocol/utils.js');
+
+const PACKET_SIZE = 32 * 1024;
+const MAX_WINDOW = 2 * 1024 * 1024;
+const WINDOW_THRESHOLD = MAX_WINDOW / 2;
+
+class ClientStderr extends ReadableStream {
+  constructor(channel, streamOpts) {
+    super(streamOpts);
+
+    this._channel = channel;
+  }
+  _read(n) {
+    if (this._channel._waitChanDrain) {
+      this._channel._waitChanDrain = false;
+      if (this._channel.incoming.window <= WINDOW_THRESHOLD)
+        windowAdjust(this._channel);
+    }
+  }
+}
+
+class ServerStderr extends WritableStream {
+  constructor(channel) {
+    super({ highWaterMark: MAX_WINDOW });
+
+    this._channel = channel;
+  }
+
+  _write(data, encoding, cb) {
+    const channel = this._channel;
+    const protocol = channel._client._protocol;
+    const outgoing = channel.outgoing;
+    const packetSize = outgoing.packetSize;
+    const id = outgoing.id;
+    let window = outgoing.window;
+    const len = data.length;
+    let p = 0;
+
+    if (outgoing.state !== 'open')
+      return;
+
+    while (len - p > 0 && window > 0) {
+      let sliceLen = len - p;
+      if (sliceLen > window)
+        sliceLen = window;
+      if (sliceLen > packetSize)
+        sliceLen = packetSize;
+
+      if (p === 0 && sliceLen === len)
+        protocol.channelExtData(id, data, STDERR);
+      else
+        protocol.channelExtData(id, bufferSlice(data, p, p + sliceLen), STDERR);
+
+      p += sliceLen;
+      window -= sliceLen;
+    }
+
+    outgoing.window = window;
+
+    if (len - p > 0) {
+      if (window === 0)
+        channel._waitWindow = true;
+      if (p > 0)
+        channel._chunkErr = bufferSlice(data, p, len);
+      else
+        channel._chunkErr = data;
+      channel._chunkcbErr = cb;
+      return;
+    }
+
+    cb();
+  }
+}
+
+class Channel extends DuplexStream {
+  constructor(client, info, opts) {
+    const streamOpts = {
+      highWaterMark: MAX_WINDOW,
+      allowHalfOpen: (!opts || (opts && opts.allowHalfOpen !== false)),
+      emitClose: false,
+    };
+    super(streamOpts);
+    this.allowHalfOpen = streamOpts.allowHalfOpen;
+
+    const 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'
+      }
+    */
+    this.incoming = info.incoming;
+    this.outgoing = info.outgoing;
+    this._callbacks = [];
+
+    this._client = client;
+    this._hasX11 = false;
+    this._exit = {
+      code: undefined,
+      signal: undefined,
+      dump: undefined,
+      desc: undefined,
+    };
+
+    this.stdin = this.stdout = this;
+
+    if (server)
+      this.stderr = new ServerStderr(this);
+    else
+      this.stderr = new ClientStderr(this, streamOpts);
+
+    // Outgoing data
+    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;
+
+    this.on('finish', onFinish)
+        .on('prefinish', onFinish); // For node v0.11+
+
+    this.on('end', onEnd).on('close', onEnd);
+  }
+
+  _read(n) {
+    if (this._waitChanDrain) {
+      this._waitChanDrain = false;
+      if (this.incoming.window <= WINDOW_THRESHOLD)
+        windowAdjust(this);
+    }
+  }
+
+  _write(data, encoding, cb) {
+    const protocol = this._client._protocol;
+    const outgoing = this.outgoing;
+    const packetSize = outgoing.packetSize;
+    const id = outgoing.id;
+    let window = outgoing.window;
+    const len = data.length;
+    let p = 0;
+
+    if (outgoing.state !== 'open')
+      return;
+
+    while (len - p > 0 && window > 0) {
+      let sliceLen = len - p;
+      if (sliceLen > window)
+        sliceLen = window;
+      if (sliceLen > packetSize)
+        sliceLen = packetSize;
+
+      if (p === 0 && sliceLen === len)
+        protocol.channelData(id, data);
+      else
+        protocol.channelData(id, bufferSlice(data, p, p + sliceLen));
+
+      p += sliceLen;
+      window -= sliceLen;
+    }
+
+    outgoing.window = window;
+
+    if (len - p > 0) {
+      if (window === 0)
+        this._waitWindow = true;
+      if (p > 0)
+        this._chunk = bufferSlice(data, p, len);
+      else
+        this._chunk = data;
+      this._chunkcb = cb;
+      return;
+    }
+
+    cb();
+  }
+
+  eof() {
+    if (this.outgoing.state === 'open') {
+      this.outgoing.state = 'eof';
+      this._client._protocol.channelEOF(this.outgoing.id);
+    }
+  }
+
+  close() {
+    if (this.outgoing.state === 'open' || this.outgoing.state === 'eof') {
+      this.outgoing.state = 'closing';
+      this._client._protocol.channelClose(this.outgoing.id);
+    }
+  }
+
+  destroy() {
+    this.end();
+    this.close();
+    return this;
+  }
+
+  // Session type-specific methods =============================================
+  setWindow(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') {
+      this._client._protocol.windowChange(this.outgoing.id,
+                                          rows,
+                                          cols,
+                                          height,
+                                          width);
+    }
+  }
+
+  signal(signalName) {
+    if (this.server)
+      throw new Error('Client-only method called in server mode');
+
+    if (this.type === 'session'
+        && this.writable
+        && this.outgoing.state === 'open') {
+      this._client._protocol.signal(this.outgoing.id, signalName);
+    }
+  }
+
+  exit(statusOrSignal, 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 statusOrSignal === 'number') {
+        this._client._protocol.exitStatus(this.outgoing.id, statusOrSignal);
+      } else {
+        this._client._protocol.exitSignal(this.outgoing.id,
+                                          statusOrSignal,
+                                          coreDumped,
+                                          msg);
+      }
+    }
+  }
+
+}
+
+function onFinish() {
+  this.eof();
+  if (this.server || !this.allowHalfOpen)
+    this.close();
+  this.writable = false;
+}
+
+function onEnd() {
+  this.readable = false;
+}
+
+function windowAdjust(self) {
+  if (self.outgoing.state === 'closed')
+    return;
+  const amt = MAX_WINDOW - self.incoming.window;
+  if (amt <= 0)
+    return;
+  self.incoming.window += amt;
+  self._client._protocol.channelWindowAdjust(self.outgoing.id, amt);
+}
+
+module.exports = {
+  Channel,
+  MAX_WINDOW,
+  PACKET_SIZE,
+  windowAdjust,
+  WINDOW_THRESHOLD,
+};