nntp.cpp

/* This file is part of KDE
   Copyright (C) 2000 by Wolfram Diestel <wolfram@steloj.de>
   Copyright (C) 2005 by Tim Way <tim@way.hrcoxmail.com>
   Copyright (C) 2005 by Volker Krause <vkrause@kde.org>

   This is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License version 2 as published by the Free Software Foundation.
*/

#include "nntp.h"

#include <sys/stat.h>
#include <stdlib.h>
#include <stdio.h>

#include <QDir>
#include <QHash>
#include <QRegExp>

#include <kcomponentdata.h>
#include <kdebug.h>
#include <klocalizedstring.h>

#include <kio/ioslave_defaults.h>

#define DBG_AREA 7114
#define DBG kDebug(DBG_AREA)

#undef ERR
#define ERR kError(DBG_AREA)

using namespace KIO;

extern "C" { int KDE_EXPORT kdemain(int argc, char **argv); }

int kdemain(int argc, char **argv) {

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

  NNTPProtocol *slave;

  // Are we going to use SSL?
  if (strcasecmp(argv[1], "nntps") == 0) {
    slave = new NNTPProtocol(argv[2], argv[3], true);
  } else {
    slave = new NNTPProtocol(argv[2], argv[3], false);
  }

  slave->dispatchLoop();
  delete slave;

  return 0;
}

/****************** NNTPProtocol ************************/

NNTPProtocol::NNTPProtocol ( const QByteArray & pool, const QByteArray & app, bool isSSL )
  : TCPSlaveBase((isSSL ? "nntps" : "nntp"), pool, app, isSSL ),
    isAuthenticated( false )
{
  DBG << "=============> NNTPProtocol::NNTPProtocol";

  readBufferLen = 0;
  m_defaultPort = isSSL ? DEFAULT_NNTPS_PORT : DEFAULT_NNTP_PORT;
  m_port = m_defaultPort;
}

NNTPProtocol::~NNTPProtocol() {
  DBG << "<============= NNTPProtocol::~NNTPProtocol";

  // close connection
  nntp_close();
}

void NNTPProtocol::setHost ( const QString & host, quint16 port, const QString & user,
                             const QString & pass )
{
  DBG << ( ! user.isEmpty() ? (user+'@') : QString(""))
      << host << ":" << ( ( port == 0 ) ? m_defaultPort : port  );

  if ( isConnected() && (mHost != host || m_port != port ||
       mUser != user || mPass != pass) )
    nntp_close();

  mHost = host;
  m_port = ( ( port == 0 ) ? m_defaultPort : port );
  mUser = user;
  mPass = pass;
}

void NNTPProtocol::get( const KUrl& url )
{
  DBG << url.prettyUrl();
  QString path = QDir::cleanPath(url.path());

  // path should be like: /group/<msg_id> or /group/<serial number>
  if ( path.startsWith( '/' ) )
    path.remove( 0, 1 );
  int pos = path.indexOf( '/' );
  QString group;
  QString msg_id;
  if ( pos > 0 ) {
    group = path.left( pos );
    msg_id = path.mid( pos + 1 );
  }

  if ( group.isEmpty() || msg_id.isEmpty() ) {
    error(ERR_DOES_NOT_EXIST,path);
    return;
  }

  int res_code;
  DBG << "group:" << group << "msg:" << msg_id;

  if ( !nntp_open() )
    return;

  // select group if necessary
  if ( mCurrentGroup != group && !group.isEmpty() ) {
    infoMessage( i18n("Selecting group %1...", group ) );
    res_code = sendCommand( "GROUP " + group );
    if ( res_code == 411 ){
      error( ERR_DOES_NOT_EXIST, path );
      mCurrentGroup.clear();
      return;
    } else if ( res_code != 211 ) {
      unexpected_response( res_code, "GROUP" );
      mCurrentGroup.clear();
      return;
    }
    mCurrentGroup = group;
  }

  // get article
  infoMessage( i18n("Downloading article...") );
  res_code = sendCommand( "ARTICLE " + msg_id );
  if ( res_code == 423 || res_code == 430 ) {
    error( ERR_DOES_NOT_EXIST, path );
    return;
  } else if (res_code != 220) {
    unexpected_response(res_code,"ARTICLE");
    return;
  }

  // read and send data
  char tmp[MAX_PACKET_LEN];
  while ( true ) {
    if ( !waitForResponse( readTimeout() ) ) {
      error( ERR_SERVER_TIMEOUT, mHost );
      nntp_close();
      return;
    }
    int len = readLine( tmp, MAX_PACKET_LEN );
    const char* buffer = tmp;
    if ( len <= 0 )
      break;
    if ( len == 3 && tmp[0] == '.' && tmp[1] == '\r' && tmp[2] == '\n')
      break;
    if ( len > 1 && tmp[0] == '.' && tmp[1] == '.' ) {
      ++buffer;
      --len;
    }
    data( QByteArray::fromRawData( buffer, len ) );
  }

  // end of data
  data(QByteArray());

  // finish
  finished();
}

void NNTPProtocol::put( const KUrl &/*url*/, int /*permissions*/, KIO::JobFlags /*flags*/ )
{
  if ( !nntp_open() )
    return;
  if ( post_article() )
    finished();
}

void NNTPProtocol::special(const QByteArray& data) {
  // 1 = post article
  int cmd;
  QDataStream stream(data);

  if ( !nntp_open() )
    return;

  stream >> cmd;
  if (cmd == 1) {
    if (post_article()) finished();
  } else {
    error(ERR_UNSUPPORTED_ACTION,i18n("Invalid special command %1", cmd));
  }
}

bool NNTPProtocol::post_article() {
  DBG;

  // send post command
  infoMessage( i18n("Sending article...") );
  int res_code = sendCommand( "POST" );
  if (res_code == 440) { // posting not allowed
    error(ERR_WRITE_ACCESS_DENIED, mHost);
    return false;
  } else if (res_code != 340) { // 340: ok, send article
    unexpected_response(res_code,"POST");
    return false;
  }

  // send article now
  int result;
  bool last_chunk_had_line_ending = true;
  do {
    QByteArray buffer;
    dataReq();
    result = readData( buffer );
    DBG << "receiving data:" << buffer;
    // treat the buffer data
    if ( result > 0 ) {
      // translate "\r\n." to "\r\n.."
      int pos = 0;
      if ( last_chunk_had_line_ending && buffer[0] == '.' ) {
        buffer.insert( 0, '.' );
        pos += 2;
      }
      last_chunk_had_line_ending = ( buffer.endsWith( "\r\n" ) ); //krazy:exclude=strings
      while ( (pos = buffer.indexOf( "\r\n.", pos )) > 0) {
        buffer.insert( pos + 2, '.' );
        pos += 4;
      }

      // send data to socket, write() doesn't send the terminating 0
      write( buffer, buffer.length() );
      DBG << "writing:" << buffer;
    }
  } while ( result > 0 );

  // error occurred?
  if (result<0) {
    ERR << "error while getting article data for posting";
    nntp_close();
    return false;
  }

  // send end mark
  write( "\r\n.\r\n", 5 );

  // get answer
  res_code = evalResponse( readBuffer, readBufferLen );
  if (res_code == 441) { // posting failed
    error(ERR_COULD_NOT_WRITE, mHost);
    return false;
  } else if (res_code != 240) {
    unexpected_response(res_code,"POST");
    return false;
  }

  return true;
}


void NNTPProtocol::stat( const KUrl& url ) {
  DBG << url.prettyUrl();
  UDSEntry entry;
  QString path = QDir::cleanPath(url.path());
  QRegExp regGroup = QRegExp("^\\/?[a-z0-9\\.\\-_]+\\/?$",Qt::CaseInsensitive);
  QRegExp regMsgId = QRegExp("^\\/?[a-z0-9\\.\\-_]+\\/<\\S+>$", Qt::CaseInsensitive);
  int pos;
  QString group;
  QString msg_id;

  // / = group list
  if (path.isEmpty() || path == "/") {
    DBG << "root";
    fillUDSEntry( entry, QString(), 0, false, ( S_IWUSR | S_IWGRP | S_IWOTH ) );

  // /group = message list
  } else if (regGroup.indexIn(path) == 0) {
    if ( path.startsWith( '/' ) ) path.remove(0,1);
    if ((pos = path.indexOf('/')) > 0) group = path.left(pos);
    else group = path;
    DBG << "group:" << group;
    // postingAllowed should be ored here with "group not moderated" flag
    // as size the num of messages (GROUP cmd) could be given
    fillUDSEntry( entry, group, 0, false, ( S_IWUSR | S_IWGRP | S_IWOTH ) );

  // /group/<msg_id> = message
  } else if (regMsgId.indexIn(path) == 0) {
    pos = path.indexOf('<');
    group = path.left(pos);
    msg_id = KUrl::fromPercentEncoding( path.right(path.length()-pos).toLatin1() );
    if ( group.startsWith( '/' ) )
      group.remove( 0, 1 );
    if ((pos = group.indexOf('/')) > 0) group = group.left(pos);
    DBG << "group:" << group << "msg:" << msg_id;
    fillUDSEntry( entry, msg_id, 0, true );

  // invalid url
  } else {
    error(ERR_DOES_NOT_EXIST,path);
    return;
  }

  statEntry(entry);
  finished();
}

void NNTPProtocol::listDir( const KUrl& url ) {
  DBG << url.prettyUrl();
  if ( !nntp_open() )
    return;

  QString path = QDir::cleanPath(url.path());

  if (path.isEmpty())
  {
    KUrl newURL(url);
    newURL.setPath("/");
    DBG << "redirecting to" << newURL.prettyUrl();
    redirection(newURL);
    finished();
    return;
  }
  else if ( path == "/" ) {
    fetchGroups( url.queryItem( "since" ), url.queryItem( "desc" ) == "true" );
    finished();
  } else {
    // if path = /group
    int pos;
    QString group;
    if ( path.startsWith( '/' ) )
      path.remove( 0, 1 );
    if ((pos = path.indexOf('/')) > 0)
      group = path.left(pos);
    else
      group = path;
    QString first = url.queryItem( "first" );
    QString max = url.queryItem( "max" );
    if ( fetchGroup( group, first.toULong(), max.toULong() ) )
      finished();
  }
}

void NNTPProtocol::fetchGroups( const QString &since, bool desc )
{
  int expected;
  int res;
  if ( since.isEmpty() ) {
    // full listing
    infoMessage( i18n("Downloading group list...") );
    res = sendCommand( "LIST" );
    expected = 215;
  } else {
    // incremental listing
    infoMessage( i18n("Looking for new groups...") );
    res = sendCommand( "NEWGROUPS " + since );
    expected = 231;
  }
  if ( res != expected ) {
    unexpected_response( res, "LIST" );
    return;
  }

  // read newsgroups line by line
  QByteArray line;
  QString group;
  int pos, pos2;
  long msg_cnt;
  long access;
  UDSEntry entry;
  QHash<QString, UDSEntry> entryMap;

  // read in data and process each group. one line at a time
  while ( true ) {
    if ( ! waitForResponse( readTimeout() ) ) {
      error( ERR_SERVER_TIMEOUT, mHost );
      nntp_close();
      return;
    }
    readBufferLen = readLine ( readBuffer, MAX_PACKET_LEN );
    line = QByteArray( readBuffer, readBufferLen );
    if ( line == ".\r\n" )
      break;

    // group name
    if ((pos = line.indexOf(' ')) > 0) {

      group = line.left(pos);

      // number of messages
      line.remove(0,pos+1);
      long last = 0;
      access = 0;
      if (((pos = line.indexOf(' ')) > 0 || (pos = line.indexOf('\t')) > 0) &&
          ((pos2 = line.indexOf(' ',pos+1)) > 0 || (pos2 = line.indexOf('\t',pos+1)) > 0)) {
        last = line.left(pos).toLongLong();
        long first = line.mid(pos+1,pos2-pos-1).toLongLong();
        msg_cnt = abs(last-first+1);
        // group access rights
        switch ( line[pos2 + 1] ) {
          case 'n': access = 0; break;
          case 'm': access = S_IWUSR | S_IWGRP; break;
          case 'y': access = S_IWUSR | S_IWGRP | S_IWOTH; break;
        }
      } else {
        msg_cnt = 0;
      }

      entry.clear();
      fillUDSEntry( entry, group, msg_cnt, false, access );
      if ( !desc )
        listEntry( entry, false );
      else
        entryMap.insert( group, entry );
    }
  }

  // handle group descriptions
  QHash<QString, UDSEntry>::Iterator it = entryMap.begin();
  if ( desc ) {
    infoMessage( i18n("Downloading group descriptions...") );
    totalSize( entryMap.size() );
  }
  while ( desc ) {
    // request all group descriptions
    if ( since.isEmpty() )
      res = sendCommand( "LIST NEWSGROUPS" );
    else {
      // request only descriptions for new groups
      if ( it == entryMap.end() )
        break;
      res = sendCommand( "LIST NEWSGROUPS " + it.key() );
      ++it;
      if( res == 503 ) {
        // Information not available (RFC 2980 §2.1.6), try next group
        continue;
      }
    }
    if ( res != 215 ) {
      // No group description available or not implemented
      break;
    }

    // download group descriptions
    while ( true ) {
      if ( ! waitForResponse( readTimeout() ) ) {
        error( ERR_SERVER_TIMEOUT, mHost );
        nntp_close();
        return;
      }
      readBufferLen = readLine ( readBuffer, MAX_PACKET_LEN );
      line = QByteArray( readBuffer, readBufferLen );
      if ( line == ".\r\n" )
        break;

      //DBG << "  fetching group description: " << QString( line ).trimmed();
      int pos = line.indexOf( ' ' );
      pos = pos < 0 ? line.indexOf( '\t' ) : qMin( pos, line.indexOf( '\t' ) );
      group = line.left( pos );
      QString groupDesc = line.right( line.length() - pos ).trimmed();

      if ( entryMap.contains( group ) ) {
        entry = entryMap.take( group );
        entry.insert( KIO::UDSEntry::UDS_EXTRA, groupDesc );
        listEntry( entry, false );
      }
    }

    if ( since.isEmpty() )
      break;
  }
  // take care of groups without descriptions
  for ( QHash<QString, UDSEntry>::Iterator it = entryMap.begin(); it != entryMap.end(); ++it )
    listEntry( it.value(), false );

  entry.clear();
  listEntry( entry, true );
}

bool NNTPProtocol::fetchGroup( QString &group, unsigned long first, unsigned long max ) {
  int res_code;
  QString resp_line;

  // select group
  infoMessage( i18n("Selecting group %1...", group ) );
  res_code = sendCommand( "GROUP " + group );
  if ( res_code == 411 ) {
    error( ERR_DOES_NOT_EXIST, group );
    mCurrentGroup.clear();
    return false;
  } else if ( res_code != 211 ) {
    unexpected_response( res_code, "GROUP" );
    mCurrentGroup.clear();
    return false;
  }
  mCurrentGroup = group;

  // repsonse to "GROUP <requested-group>" command is 211 then find the message count (cnt)
  // and the first and last message followed by the group name
  unsigned long firstSerNum, lastSerNum;
  resp_line = QString::fromLatin1( readBuffer );
  QRegExp re ( "211\\s+(\\d+)\\s+(\\d+)\\s+(\\d+)");
  if ( re.indexIn( resp_line ) != -1 ) {
    firstSerNum = re.cap( 2 ).toLong();
    lastSerNum = re.cap( 3 ).toLong();
  } else {
    error( ERR_INTERNAL, i18n("Could not extract message serial numbers from server response:\n%1",
       resp_line ) );
    return false;
  }

  if (firstSerNum == 0)
    return true;
  first = qMax( first, firstSerNum );
  if ( lastSerNum < first ) { // No need to fetch anything
    // note: this also ensure that "lastSerNum - first" is not negative
    // in the next test (in "unsigned long" computation this leads to an overflow
    return true;
  }
  if ( max > 0 && lastSerNum - first > max )
    first = lastSerNum - max + 1;

  DBG << "Starting from serial number: " << first << " of " << firstSerNum << " - " << lastSerNum;
  setMetaData( "FirstSerialNumber", QString::number( firstSerNum ) );
  setMetaData( "LastSerialNumber", QString::number( lastSerNum ) );

  infoMessage( i18n("Downloading new headers...") );
  totalSize( lastSerNum - first );
  bool notSupported = true;
  if ( fetchGroupXOVER( first, notSupported ) )
    return true;
  else if ( notSupported )
    return fetchGroupRFC977( first );
  return false;
}


bool NNTPProtocol::fetchGroupRFC977( unsigned long first )
{
  UDSEntry entry;

  // set article pointer to first article and get msg-id of it
  int res_code = sendCommand( "STAT " + QString::number( first ) );
  QString resp_line = readBuffer;
  if (res_code != 223) {
    unexpected_response(res_code,"STAT");
    return false;
  }

  //STAT res_line: 223 nnn <msg_id> ...
  QString msg_id;
  int pos, pos2;
  if ((pos = resp_line.indexOf('<')) > 0 && (pos2 = resp_line.indexOf('>',pos+1))) {
    msg_id = resp_line.mid(pos,pos2-pos+1);
    fillUDSEntry( entry, msg_id, 0, true );
    listEntry( entry, false );
  } else {
    error(ERR_INTERNAL,i18n("Could not extract first message id from server response:\n%1",
      resp_line));
    return false;
  }

  // go through all articles
  while (true) {
    res_code = sendCommand("NEXT");
    if (res_code == 421) {
      // last artice reached
      entry.clear();
      listEntry( entry, true );
      return true;
    } else if (res_code != 223) {
      unexpected_response(res_code,"NEXT");
      return false;
    }

    //res_line: 223 nnn <msg_id> ...
    resp_line = readBuffer;
    if ((pos = resp_line.indexOf('<')) > 0 && (pos2 = resp_line.indexOf('>',pos+1))) {
      msg_id = resp_line.mid(pos,pos2-pos+1);
      entry.clear();
      fillUDSEntry( entry, msg_id, 0, true );
      listEntry( entry, false );
    } else {
      error(ERR_INTERNAL,i18n("Could not extract message id from server response:\n%1",
        resp_line));
      return false;
    }
  }
  return true; // Not reached
}


bool NNTPProtocol::fetchGroupXOVER( unsigned long first, bool &notSupported )
{
  notSupported = false;

  QString line;
  QStringList headers;

  int res = sendCommand( "LIST OVERVIEW.FMT" );
  if ( res == 215 ) {
    while ( true ) {
      if ( ! waitForResponse( readTimeout() ) ) {
        error( ERR_SERVER_TIMEOUT, mHost );
        nntp_close();
        return false;
      }
      readBufferLen = readLine ( readBuffer, MAX_PACKET_LEN );
      line = QString::fromLatin1( readBuffer, readBufferLen );
      if ( line == ".\r\n" )
        break;
      headers << line.trimmed();
      DBG << "OVERVIEW.FMT:" << line.trimmed();
    }
  } else {
    // fallback to defaults
    headers << "Subject:" << "From:" << "Date:" << "Message-ID:"
        << "References:" << "Bytes:" << "Lines:";
  }

  res = sendCommand( "XOVER " + QString::number( first ) + '-' );
  if ( res == 420 )
    return true; // no articles selected
  if ( res == 500 )
    notSupported = true; // unknwon command
  if ( res != 224 ) {
    unexpected_response( res, "XOVER" );
    return false;
  }

  long msgSize;
  QString name;
  UDSEntry entry;
  int udsType;

  QStringList fields;
  while ( true ) {
    if ( ! waitForResponse( readTimeout() ) ) {
      error( ERR_SERVER_TIMEOUT, mHost );
      nntp_close();
      return false;
    }
    readBufferLen = readLine ( readBuffer, MAX_PACKET_LEN );
    line = QString::fromLatin1( readBuffer, readBufferLen );
    if ( line == ".\r\n" ) {
      entry.clear();
      listEntry( entry, true );
      return true;
    }

    fields = line.split( '\t', QString::KeepEmptyParts);
    msgSize = 0;
    entry.clear();
    udsType = KIO::UDSEntry::UDS_EXTRA;
    QStringList::ConstIterator it = headers.constBegin();
    QStringList::ConstIterator it2 = fields.constBegin();
    // first entry is the serial number
    name = (*it2);
    ++it2;
    for ( ; it != headers.constEnd() && it2 != fields.constEnd(); ++it, ++it2 ) {
      if ( (*it) == "Bytes:" ) {
        msgSize = (*it2).toLong();
        continue;
      }
      QString atomStr;
      if ( (*it).endsWith( QLatin1String( "full" ) ) )
        if ( (*it2).trimmed().isEmpty() )
          atomStr = (*it).left( (*it).indexOf( ':' ) + 1 ); // strip of the 'full' suffix
        else
          atomStr = (*it2).trimmed();
      else
        atomStr = (*it) + ' ' + (*it2).trimmed();
      entry.insert( udsType++, atomStr );
      if ( udsType >= KIO::UDSEntry::UDS_EXTRA_END )
        break;
    }
    fillUDSEntry( entry, name, msgSize, true );
    listEntry( entry, false );
  }
  return true; // not reached
}


void NNTPProtocol::fillUDSEntry( UDSEntry& entry, const QString& name, long size,
  bool is_article, long access ) {

  long posting=0;

  // entry name
  entry.insert(KIO::UDSEntry::UDS_NAME, name);

  // entry size
  entry.insert(KIO::UDSEntry::UDS_SIZE, size);

  // file type
  entry.insert(KIO::UDSEntry::UDS_FILE_TYPE, is_article? S_IFREG : S_IFDIR);

  // access permissions
  posting = postingAllowed? access : 0;
  long long accessVal = (is_article)? (S_IRUSR | S_IRGRP | S_IROTH) :
    (S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH | posting);
  entry.insert(KIO::UDSEntry::UDS_ACCESS, accessVal);

  entry.insert(KIO::UDSEntry::UDS_USER, mUser.isEmpty() ? QString::fromLatin1("root") : mUser);

  /*
  entry->insert(UDS_GROUP, QString::fromLatin1("root"));
  */

  // MIME type
  if (is_article) {
    entry.insert( KIO::UDSEntry::UDS_MIME_TYPE, QString::fromLatin1("message/news") );
  }
}

void NNTPProtocol::nntp_close () {
  if ( isConnected() ) {
    write( "QUIT\r\n", 6 );
    disconnectFromHost();
    isAuthenticated = false;
  }
  mCurrentGroup.clear();
}

bool NNTPProtocol::nntp_open()
{
  // if still connected reuse connection
  if ( isConnected() ) {
    DBG << "reusing old connection";
    return true;
  }

  DBG << "  nntp_open -- creating a new connection to" << mHost << ":" << m_port;
  // create a new connection (connectToHost() includes error handling)
  infoMessage( i18n("Connecting to server...") );
  if ( connectToHost( (isAutoSsl() ? "nntps" : "nntp"), mHost, m_port ) )
  {
    DBG << "  nntp_open -- connection is open";

    // read greeting
    int res_code = evalResponse( readBuffer, readBufferLen );

    /* expect one of
         200 server ready - posting allowed
         201 server ready - no posting allowed
    */
    if ( ! ( res_code == 200 || res_code == 201 ) )
    {
      unexpected_response(res_code,"CONNECT");
      return false;
    }

    DBG << "  nntp_open -- greating was read res_code :" << res_code;

    res_code = sendCommand("MODE READER");

    // TODO: not in RFC 977, so we should not abort here
    if ( !(res_code == 200 || res_code == 201) ) {
      unexpected_response( res_code, "MODE READER" );
      return false;
    }

    // let local class know whether posting is allowed or not
    postingAllowed = (res_code == 200);

    // activate TLS if requested
    if ( metaData("tls") == "on" ) {
      if ( sendCommand( "STARTTLS" ) != 382 ) {
        error( ERR_COULD_NOT_CONNECT, i18n("This server does not support TLS") );
        return false;
      }
      if ( !startSsl() ) {
        error( ERR_COULD_NOT_CONNECT, i18n("TLS negotiation failed") );
        return false;
      }
    }

    // *try* to authenticate now (see bug#167718)
    authenticate();

    return true;
  }

  return false;
}

int NNTPProtocol::sendCommand( const QString &cmd )
{
  int res_code = 0;

  if ( !nntp_open() ) {
    ERR << "NOT CONNECTED, cannot send cmd" << cmd;
    return 0;
  }

  DBG << "cmd:" << cmd;

  write( cmd.toLatin1(), cmd.length() );
  // check the command for proper termination
  if ( !cmd.endsWith( QLatin1String( "\r\n" ) ) )
    write( "\r\n", 2 );
  res_code =  evalResponse( readBuffer, readBufferLen );

  // if authorization needed send user info
  if (res_code == 480) {
    DBG << "auth needed, sending user info";

    if ( mUser.isEmpty() || mPass.isEmpty() ) {
      KIO::AuthInfo authInfo;
      authInfo.username = mUser;
      authInfo.password = mPass;
      if ( openPasswordDialog( authInfo ) ) {
        mUser = authInfo.username;
        mPass = authInfo.password;
      }
    }
    if ( mUser.isEmpty() || mPass.isEmpty() )
      return res_code;

    res_code = authenticate();
    if (res_code != 281) {
      // error should be handled by invoking function
      return res_code;
    }

    // ok now, resend command
    write( cmd.toLatin1(), cmd.length() );
    if ( !cmd.endsWith( QLatin1String( "\r\n" ) ) )
      write( "\r\n", 2 );
    res_code = evalResponse( readBuffer, readBufferLen );
  }

  return res_code;
}

int NNTPProtocol::authenticate()
{
  int res_code = 0;

  if( isAuthenticated ) {
    // already authenticated
    return 281;
  }

  if( mUser.isEmpty() || mPass.isEmpty() ) {
    return 281; // failsafe : maybe add a "relax" mode to optionally ask user/pwd.
  }

  // send username to server and confirm response
  write( "AUTHINFO USER ", 14 );
  write( mUser.toLatin1(), mUser.length() );
  write( "\r\n", 2 );
  res_code = evalResponse( readBuffer, readBufferLen );

  if( res_code == 281 ) {
    // no password needed (RFC 2980 3.1.1 does not required one)
    return res_code;
  }
  if (res_code != 381) {
    // error should be handled by invoking function
    return res_code;
  }

  // send password
  write( "AUTHINFO PASS ", 14 );
  write( mPass.toLatin1(), mPass.length() );
  write( "\r\n", 2 );
  res_code = evalResponse( readBuffer, readBufferLen );

  if( res_code == 281 ) {
    isAuthenticated = true;
  }

  return res_code;
}

void NNTPProtocol::unexpected_response( int res_code, const QString &command )
{
  ERR << "Unexpected response to" << command << "command: (" << res_code << ")"
      << readBuffer;

  // See RFC 3977 appendix C "Summary of Response Codes"
  switch ( res_code ) {
    case 205: // connection closed by the server: this can happens, e.g. if the session timeout on the server side
      // Not the same thing, but use the same message as code 400 anyway.
    case 400: // temporary issue on the server
      error( ERR_INTERNAL_SERVER,
             i18n( "The server %1 could not handle your request.\n"
                   "Please try again now, or later if the problem persists.", mHost ) );
      break;
    case 480: // credential request
      error( ERR_COULD_NOT_LOGIN,
             i18n( "You need to authenticate to access the requested resource." ) );
      break;
    case 481: // wrong credential (TODO: place a specific message for this case)
      error( ERR_COULD_NOT_LOGIN,
             i18n( "The supplied login and/or password are incorrect." ) );
      break;
    case 502:
      error( ERR_ACCESS_DENIED, mHost );
      break;
    default:
      error( ERR_INTERNAL, i18n( "Unexpected server response to %1 command:\n%2", command, readBuffer ) );
  }

  nntp_close();
}

int NNTPProtocol::evalResponse ( char *data, ssize_t &len )
{
  if ( !waitForResponse( responseTimeout() ) ) {
    error( ERR_SERVER_TIMEOUT , mHost );
    nntp_close();
    return -1;
  }
  len = readLine( data, MAX_PACKET_LEN );

  if ( len < 3 )
    return -1;

  // get the first three characters. should be the response code
  int respCode = ( ( data[0] - 48 ) * 100 ) + ( ( data[1] - 48 ) * 10 ) + ( ( data[2] - 48 ) );

  DBG << "got:" << respCode;

  return respCode;
}

/* not really necessary, because the slave has to
   use the KIO::Error's instead, but let this here for
   documentation of the NNTP response codes and may
   by later use.
QString& NNTPProtocol::errorStr(int resp_code) {
  QString ret;

  switch (resp_code) {
  case 100: ret = "help text follows"; break;
  case 199: ret = "debug output"; break;

  case 200: ret = "server ready - posting allowed"; break;
  case 201: ret = "server ready - no posting allowed"; break;
  case 202: ret = "slave status noted"; break;
  case 205: ret = "closing connection - goodbye!"; break;
  case 211: ret = "group selected"; break;
  case 215: ret = "list of newsgroups follows"; break;
  case 220: ret = "article retrieved - head and body follow"; break;
  case 221: ret = "article retrieved - head follows"; break;
  case 222: ret = "article retrieved - body follows"; break;
  case 223: ret = "article retrieved - request text separately"; break;
  case 230: ret = "list of new articles by message-id follows"; break;
  case 231: ret = "list of new newsgroups follows"; break;
  case 235: ret = "article transferred ok"; break;
  case 240: ret = "article posted ok"; break;

  case 335: ret = "send article to be transferred"; break;
  case 340: ret = "send article to be posted"; break;

  case 400: ret = "service discontinued"; break;
  case 411: ret = "no such news group"; break;
  case 412: ret = "no newsgroup has been selected"; break;
  case 420: ret = "no current article has been selected"; break;
  case 421: ret = "no next article in this group"; break;
  case 422: ret = "no previous article in this group"; break;
  case 423: ret = "no such article number in this group"; break;
  case 430: ret = "no such article found"; break;
  case 435: ret = "article not wanted - do not send it"; break;
  case 436: ret = "transfer failed - try again later"; break;
  case 437: ret = "article rejected - do not try again"; break;
  case 440: ret = "posting not allowed"; break;
  case 441: ret = "posting failed"; break;

  case 500: ret = "command not recognized"; break;
  case 501: ret = "command syntax error"; break;
  case 502: ret = "access restriction or permission denied"; break;
  case 503: ret = "program fault - command not performed"; break;
  default:  ret = QString("unknown NNTP response code %1").arg(resp_code);
  }

  return ret;
}
*/