Correctly handle FTP servers which unexpectedly close the control connection.

net/ftp/ftp_network_transaction.cc

 // Copyright (c) 2008 The Chromium Authors. All rights reserved.  Use of this
 // source code is governed by a BSD-style license that can be found in the
 // LICENSE file.
 
 #include "net/ftp/ftp_network_transaction.h"
 
 #include "base/compiler_specific.h"
 #include "base/string_util.h"
 #include "net/base/connection_type_histograms.h"
 #include "net/base/escape.h"
@@ skipping 504 matching lines @@
 
 int FtpNetworkTransaction::DoCtrlRead() {
   next_state_ = STATE_CTRL_READ_COMPLETE;
   return ctrl_socket_->Read(
       read_ctrl_buf_,
       kCtrlBufLen,
       &io_callback_);
 }
 
 int FtpNetworkTransaction::DoCtrlReadComplete(int result) {
+  if (result == 0) {
+    // Some servers (for example Pure-FTPd) apparently close the control
+    // connection when anonymous login is not permitted. For more details
+    // see http://crbug.com/25023.
+    if (command_sent_ == COMMAND_USER && username_ == L"anonymous")
+      response_.needs_auth = true;
+    return Stop(ERR_EMPTY_RESPONSE);

[wtc, 2009/10/31 15:16:48]

I think ERR_EMPTY_RESPONSE is fine.  We can also add an
FTP error code for this condition (ERR_FTP_CONTROL_CONNECTION_CLOSED?).

+  }
   if (result < 0)
     return Stop(result);
 
   ctrl_response_buffer_->ConsumeData(read_ctrl_buf_->data(), result);
 
   if (!ctrl_response_buffer_->ResponseAvailable()) {
     // Read more data from the control socket.
     next_state_ = STATE_CTRL_READ;
     return OK;
   }
@@ skipping 549 matching lines @@
   read_data_buf_->data()[0] = 0;
   return data_socket_->Read(read_data_buf_, read_data_buf_len_,
                             &io_callback_);
 }
 
 int FtpNetworkTransaction::DoDataReadComplete(int result) {
   return result;
 }
 
 }  // namespace net