ftp.cpp

一个用QT开发的FTP客户端

// -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 2; c-file-style: "stroustrup" -*-
/*  This file is part of the KDE libraries
    Copyright (C) 2000-2006 David Faure <[e-mail]>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
*/

/*
    Recommended reading explaining FTP details and quirks:
      http://cr.yp.to/ftp.html  (by D.J. Bernstein)

    RFC:
      RFC  959 "File Transfer Protocol (FTP)"
      RFC 1635 "How to Use Anonymous FTP"
      RFC 2428 "FTP Extensions for IPv6 and NATs" (defines EPRT and EPSV)
*/

#define  KIO_FTP_PRIVATE_INCLUDE
#include "ftp.h"

#include <sys/stat.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif

#include <netinet/in.h>
#include <arpa/inet.h>

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>

#if TIME_WITH_SYS_TIME
#include <time.h>
#endif

#include <QtCore/QDir>
#include <QtNetwork/QHostAddress>
#include <QtNetwork/QTcpServer>

#include <kdebug.h>
#include <kglobal.h>
#include <klocale.h>
#include <kcomponentdata.h>
#include <kmimetype.h>
#include <kio/ioslave_defaults.h>
#include <kio/slaveconfig.h>
#include <kremoteencoding.h>
#include <ksocketfactory.h>
#include <kde_file.h>
#include <kconfiggroup.h>
#include <kmessagebox.h>

#ifdef HAVE_STRTOLL
  #define charToLongLong(a) strtoll(a, 0, 10)
#else
  #define charToLongLong(a) strtol(a, 0, 10)
#endif

#define FTP_LOGIN   "anonymous"
#define FTP_PASSWD  "anonymous@"

//#undef  kDebug
#define ENABLE_CAN_RESUME

// JPF: somebody should find a better solution for this or move this to KIO
// JPF: anyhow, in KDE 3.2.0 I found diffent MAX_IPC_SIZE definitions!
namespace KIO {
    enum buffersizes
    {  /**
        * largest buffer size that should be used to transfer data between
        * KIO slaves using the data() function
        */
        maximumIpcSize = 32 * 1024,
        /**
         * this is a reasonable value for an initial read() that a KIO slave
         * can do to obtain data via a slow network connection.
         */
        initialIpcSize =  2 * 1024,
        /**
         * recommended size of a data block passed to findBufferFileType()
         */
        mimimumMimeSize =     1024
    };

    // JPF: this helper was derived from write_all in file.cc (FileProtocol).
    static // JPF: in ftp.cc we make it static
    /**
     * This helper handles some special issues (blocking and interrupted
     * system call) when writing to a file handle.
     *
     * @return 0 on success or an error code on failure (ERR_COULD_NOT_WRITE,
     * ERR_DISK_FULL, ERR_CONNECTION_BROKEN).
     */
   int WriteToFile(int fd, const char *buf, size_t len)
   {
      while (len > 0)
      {  // JPF: shouldn't there be a KDE_write?
         ssize_t written = write(fd, buf, len);
         if (written >= 0)
         {   buf += written;
             len -= written;
             continue;
         }
         switch(errno)
         {   case EINTR:   continue;
             case EPIPE:   return ERR_CONNECTION_BROKEN;
             case ENOSPC:  return ERR_DISK_FULL;
             default:      return ERR_COULD_NOT_WRITE;
         }
      }
      return 0;
   }
}

KIO::filesize_t Ftp::UnknownSize = (KIO::filesize_t)-1;

using namespace KIO;

extern "C" int KDE_EXPORT kdemain( int argc, char **argv )
{
  KComponentData componentData( "kio_ftpc", "kdelibs4" );
  ( void ) KGlobal::locale();

  kDebug(7102) << "Starting " << getpid();

  if (argc != 4)
  {
     fprintf(stderr, "Usage: kio_ftps protocol domain-socket1 domain-socket2\n");
     exit(-1);
  }

  Ftp slave(argv[2], argv[3]);
  slave.dispatchLoop();

  kDebug(7102) << "Done";
  return 0;
}

//===============================================================================
// Ftp
//===============================================================================

Ftp::Ftp( const QByteArray &pool, const QByteArray &app )
    : SlaveBase( "ftps", pool, app )
{
  // init the socket data
  m_data = m_control = NULL;
  ftpCloseControlConnection();

  // init other members
  m_port = 0;
  kDebug(7102) << "Ftp::Ftp()";
}


Ftp::~Ftp()
{
  kDebug(7102) << "Ftp::~Ftp()";
  closeConnection();
}

/**
 * This closes a data connection opened by ftpOpenDataConnection().
 */
void Ftp::ftpCloseDataConnection()
{
  delete m_data;
  m_data = NULL;
}

/**
 * This closes a control connection opened by ftpOpenControlConnection() and reinits the
 * related states.  This method gets called from the constructor with m_control = NULL.
 */
void Ftp::ftpCloseControlConnection()
{
  m_extControl = 0;
  delete m_control;
  m_control = NULL;
  m_cDataMode = 0;
  m_bLoggedOn = false;    // logon needs control connction
  m_bTextMode = false;
  m_bBusy = false;
}

/**
 * Returns the last response from the server (iOffset >= 0)  -or-  reads a new response
 * (iOffset < 0). The result is returned (with iOffset chars skipped for iOffset > 0).
 */
const char* Ftp::ftpResponse(int iOffset)
{
  assert(m_control != NULL);    // must have control connection socket
  const char *pTxt = m_lastControlLine.data();

  // read the next line ...
  if(iOffset < 0)
  {
    int  iMore = 0;
    m_iRespCode = 0;

    // If the server sends multiline responses "nnn-text" we loop here until
    // a final "nnn text" line is reached. Only data from the final line will
    // be stored. Some servers (OpenBSD) send a single "nnn-" followed by
    // optional lines that start with a space and a final "nnn text" line.
    do {
      while (!m_control->canReadLine() && m_control->waitForReadyRead()) {}
      m_lastControlLine = m_control->readLine();
      pTxt = m_lastControlLine.data();
      int nBytes = m_lastControlLine.size();
      int iCode  = atoi(pTxt);
      if(iCode > 0) m_iRespCode = iCode;

      // ignore lines starting with a space in multiline response
      if(iMore != 0 && pTxt[0] == 32)
        ;
      // otherwise the line should start with "nnn-" or "nnn "
      else if(nBytes < 4 || iCode < 100)
        iMore = 0;
      // we got a valid line, now check for multiline responses ...
      else if(iMore == 0 && pTxt[3] == '-')
        iMore = iCode;
      // "nnn " ends multiline mode ...
      else if(iMore != 0 && (iMore != iCode || pTxt[3] != '-'))
        iMore = 0;

      if(iMore != 0)
         kDebug(7102) << "    > " << pTxt;
    } while(iMore != 0);
    kDebug(7102) << "resp> " << pTxt;

    m_iRespType = (m_iRespCode > 0) ? m_iRespCode / 100 : 0;
  }

  // return text with offset ...
  while(iOffset-- > 0 && pTxt[0])
    pTxt++;
  return pTxt;
}


void Ftp::closeConnection()
{
  if(m_control != NULL || m_data != NULL)
    kDebug(7102) << "Ftp::closeConnection m_bLoggedOn=" << m_bLoggedOn << " m_bBusy=" << m_bBusy;

  if(m_bBusy)              // ftpCloseCommand not called
  {
    kWarning(7102) << "Ftp::closeConnection Abandoned data stream";
    ftpCloseDataConnection();
  }

  if(m_bLoggedOn)           // send quit
  {
    if( !ftpSendCmd( "quit", 0 ) || (m_iRespType != 2) )
      kWarning(7102) << "Ftp::closeConnection QUIT returned error: " << m_iRespCode;
  }

  // close the data and control connections ...
  ftpCloseDataConnection();
  ftpCloseControlConnection();
}

void Ftp::setHost( const QString& _host, quint16 _port, const QString& _user,
                   const QString& _pass )
{
  kDebug(7102) << "Ftp::setHost (" << getpid() << "): " << _host << " port=" << _port;

  m_proxyURL = metaData("UseProxy");
  m_bUseProxy = (m_proxyURL.isValid() && m_proxyURL.protocol() == "ftp");

  if ( m_host != _host || m_port != _port ||
       m_user != _user || m_pass != _pass )
    closeConnection();

  m_host = _host;
  m_port = _port;
  m_user = _user;
  m_pass = _pass;
}

void Ftp::openConnection()
{
  ftpOpenConnection(loginExplicit);
}

bool Ftp::ftpOpenConnection (LoginMode loginMode)
{
  // check for implicit login if we are already logged on ...
  if(loginMode == loginImplicit && m_bLoggedOn)
  {
    assert(m_control != NULL);    // must have control connection socket
    return true;
  }

  kDebug(7102) << "ftpOpenConnection " << m_host << ":" << m_port << " "
                << m_user << " [password hidden]";

  infoMessage( i18n("Opening connection to host %1", m_host) );

  if ( m_host.isEmpty() )
  {
    error( ERR_UNKNOWN_HOST, QString() );
    return false;
  }

  assert( !m_bLoggedOn );

  m_initialPath.clear();
  m_currentPath.clear();

  QString host = m_bUseProxy ? m_proxyURL.host() : m_host;
  int port = m_bUseProxy ? m_proxyURL.port() : m_port;

  if (!ftpOpenControlConnection(host, port) )
    return false;          // error emitted by ftpOpenControlConnection
  infoMessage( i18n("Connected to host %1", m_host) );

  if(loginMode != loginDefered)
  {
    m_bLoggedOn = ftpLogin();
    if( !m_bLoggedOn )
      return false;       // error emitted by ftpLogin
  }

  m_bTextMode = config()->readEntry("textmode", false);
  connected();

  return true;
}

/**
 * Called by @ref openConnection. It opens the control connection to the ftp server.
 *
 * @return true on success.
 */
bool Ftp::ftpOpenControlConnection( const QString &host, int port, bool ignoreSslErrors )
{
  m_bIgnoreSslErrors = ignoreSslErrors;

  // implicitly close, then try to open a new connection ...
  closeConnection();
  QString sErrorMsg;

  // now connect to the server and read the login message ...
  if (port == 0)
    port = 21;                  // default FTP port

	m_control = new QSslSocket();
	KSocketFactory::synchronousConnectToHost(m_control, "ftps", host, port, connectTimeout() * 1000);
  int iErrorCode = m_control->state() == QAbstractSocket::ConnectedState ? 0 : ERR_COULD_NOT_CONNECT;

  // on connect success try to read the server message...
  if(iErrorCode == 0)
  {
    const char* psz = ftpResponse(-1);
    if(m_iRespType != 2)
    { // login not successful, do we have an message text?
      if(psz[0])
        sErrorMsg = i18n("%1.\n\nReason: %2", host, psz);
      iErrorCode = ERR_COULD_NOT_CONNECT;
    }
  }
  else
  {
    if (m_control->error() == QAbstractSocket::HostNotFoundError)
      iErrorCode = ERR_UNKNOWN_HOST;

    sErrorMsg = QString("%1: %2").arg(host).arg(m_control->errorString());
  }

  // Send unencrypted "AUTH TLS" request.
  // TODO: redirect to FTP fallback on negative response.

  if(iErrorCode == 0) 
  {
    bool authSucc = (ftpSendCmd("AUTH TLS") && (m_iRespCode == 234));
    if (!authSucc)
    {
      iErrorCode = ERR_SLAVE_DEFINED;
      sErrorMsg = i18n("The FTP server does not seem to support ftps-encryption.");
    }
  }

  // Starts the encryption

  if(iErrorCode == 0) 
  {
    // If the method has been called with ignoreSslErrors, make the ssl socket
    // ignore the errors during handshakes. 

    if (ignoreSslErrors) m_control->ignoreSslErrors();
    m_control->startClientEncryption();

    if (!m_control->waitForEncrypted(connectTimeout() * 1000)) 
    {
      // It is quite common, that the TLS handshake fails, as the majority 
      // of certificates are self signed, and thus the host cannot be verified.
      // If the user wants to continue nevertheless, this method is called
      // again, with the "ignoreSslErrors" flag.

      bool doNotIgnore = false;

      QList<QSslError> errors = m_control->sslErrors();

      for (int i = 0; i < errors.size(); ++i) 
      {
	if (messageBox(WarningContinueCancel, errors.at(i).errorString(), 
	"TLS Handshake Error", 
	i18n("&Continue"), 
	i18n("&Cancel")) == KMessageBox::Cancel) doNotIgnore = false; 	
      }

      if (doNotIgnore) 
      {
	iErrorCode = ERR_SLAVE_DEFINED;
	sErrorMsg = i18n("TLS Handshake Error.");
      }
      else
      {