MediaCurl.cc

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|                           / / \ V /|  _/  _/                         |
|                          / /__ | | | | | |                           |
|                         /_____||_| |_| |_|                           |
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\---------------------------------------------------------------------*/
#include <iostream>
#include <chrono>
#include <list>
 
#include <zypp/base/Logger.h>
#include <zypp/ExternalProgram.h>
#include <zypp/base/String.h>
#include <zypp/base/Gettext.h>
#include <zypp-core/parser/Sysconfig>
#include <zypp/base/Gettext.h>
 
#include <zypp/media/MediaCurl.h>
#include <zypp-core/zyppng/base/private/linuxhelpers_p.h>
#include <zypp-core/base/userrequestexception.h>
#include <zypp-curl/ProxyInfo>
#include <zypp-curl/auth/CurlAuthData>
#include <zypp-media/auth/CredentialManager>
#include <zypp-curl/CurlConfig>
#include <zypp-curl/private/curlhelper_p.h>
#include <zypp/Target.h>
#include <zypp/ZYppFactory.h>
#include <zypp/ZConfig.h>
#include <zypp/zypp_detail/ZYppImpl.h> // for zypp_poll
 
#include <cstdlib>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <dirent.h>
#include <unistd.h>
#include <glib.h>
 
using std::endl;
 
namespace internal {
  using namespace zypp;
  struct OptionalDownloadProgressReport : public callback::ReceiveReport<media::DownloadProgressReport>
  {
    using TimePoint = std::chrono::steady_clock::time_point;
 
    OptionalDownloadProgressReport( bool isOptional=false )
    : _oldRec { Distributor::instance().getReceiver() }
    , _isOptional { isOptional }
    { connect(); }
 
    ~OptionalDownloadProgressReport()
    { if ( _oldRec ) Distributor::instance().setReceiver( *_oldRec ); else Distributor::instance().noReceiver(); }
 
    void reportbegin() override
    { if ( _oldRec ) _oldRec->reportbegin(); }
 
    void reportend() override
    { if ( _oldRec ) _oldRec->reportend(); }
 
    void report( const UserData & userData_r = UserData() ) override
    { if ( _oldRec ) _oldRec->report( userData_r ); }
 
 
    void start( const Url & file_r, Pathname localfile_r ) override
    {
      if ( not _oldRec ) return;
      if ( _isOptional ) {
        // delay start until first data are received.
        _startFile      = file_r;
        _startLocalfile = std::move(localfile_r);
        return;
      }
      _oldRec->start( file_r, localfile_r );
    }
 
    bool progress( int value_r, const Url & file_r, double dbps_avg_r = -1, double dbps_current_r = -1 ) override
    {
      if ( not _oldRec ) return true;
      if ( notStarted() ) {
        if ( not ( value_r || dbps_avg_r || dbps_current_r ) )
          return true;
        sendStart();
      }
 
      //static constexpr std::chrono::milliseconds minfequency { 1000 }; only needed if we'd avoid sending reports without change
      static constexpr std::chrono::milliseconds maxfequency { 100 };
      TimePoint now { TimePoint::clock::now() };
      TimePoint::duration elapsed { now - _lastProgressSent };
      if ( elapsed < maxfequency )
        return true;  // continue
      _lastProgressSent = now;
      return _oldRec->progress( value_r, file_r, dbps_avg_r, dbps_current_r );
    }
 
    Action problem( const Url & file_r, Error error_r, const std::string & description_r ) override
    {
      if ( not _oldRec || notStarted() ) return ABORT;
      return _oldRec->problem( file_r, error_r, description_r );
    }
 
    void finish( const Url & file_r, Error error_r, const std::string & reason_r ) override
    {
      if ( not _oldRec || notStarted() ) return;
      _oldRec->finish( file_r, error_r, reason_r );
    }
 
  private:
    // _isOptional also indicates the delayed start
    bool notStarted() const
    { return _isOptional; }
 
    void sendStart()
    {
      if ( _isOptional ) {
        // we know _oldRec is valid...
        _oldRec->start( std::move(_startFile), std::move(_startLocalfile) );
        _isOptional = false;
      }
    }
 
  private:
    Receiver *const _oldRec;
    bool     _isOptional;
    Url      _startFile;
    Pathname _startLocalfile;
    TimePoint _lastProgressSent;
  };
 
  struct ProgressData
  {
    ProgressData( CURL *curl, time_t timeout = 0, const zypp::Url & url = zypp::Url(),
                  zypp::ByteCount expectedFileSize_r = 0,
                  zypp::callback::SendReport<zypp::media::DownloadProgressReport> *_report = nullptr );
 
    void updateStats( curl_off_t dltotal = 0.0, curl_off_t dlnow = 0.0 );
 
    int reportProgress() const;
 
    CURL * curl()
    { return _curl; }
 
    bool timeoutReached() const
    { return _timeoutReached; }
 
    bool fileSizeExceeded() const
    { return _fileSizeExceeded; }
 
    ByteCount expectedFileSize() const
    { return _expectedFileSize; }
 
    void expectedFileSize( ByteCount newval_r )
    { _expectedFileSize = newval_r; }
 
  private:
    CURL *      _curl;
    zypp::Url   _url;
    time_t      _timeout;
    bool        _timeoutReached;
    bool        _fileSizeExceeded;
    ByteCount   _expectedFileSize;
    zypp::callback::SendReport<zypp::media::DownloadProgressReport> *report;
 
    time_t _timeStart   = 0;    
    time_t _timeLast    = 0;    
    time_t _timeRcv     = 0;    
    time_t _timeNow     = 0;    
 
    curl_off_t _dnlTotal = 0.0; 
    curl_off_t _dnlLast  = 0.0; 
    curl_off_t _dnlNow   = 0.0; 
 
    int    _dnlPercent= 0;      
 
    double _drateTotal= 0.0;    
    double _drateLast   = 0.0;  
  };
 
 
 
  ProgressData::ProgressData(CURL *curl, time_t timeout, const Url &url, ByteCount expectedFileSize_r, zypp::callback::SendReport< zypp::media::DownloadProgressReport> *_report)
    : _curl( curl )
    , _url( url )
    , _timeout( timeout )
    , _timeoutReached( false )
    , _fileSizeExceeded ( false )
    , _expectedFileSize( expectedFileSize_r )
    , report( _report )
  {}
 
  void ProgressData::updateStats( curl_off_t dltotal, curl_off_t dlnow )
  {
    time_t now = _timeNow = time(0);
 
    // If called without args (0.0), recompute based on the last values seen
    if ( dltotal && dltotal != _dnlTotal )
      _dnlTotal = dltotal;
 
    if ( dlnow && dlnow != _dnlNow )
    {
      _timeRcv = now;
      _dnlNow = dlnow;
    }
 
    // init or reset if time jumps back
    if ( !_timeStart || _timeStart > now )
      _timeStart = _timeLast = _timeRcv = now;
 
    // timeout condition
    if ( _timeout )
      _timeoutReached = ( (now - _timeRcv) > _timeout );
 
    // check if the downloaded data is already bigger than what we expected
    _fileSizeExceeded = _expectedFileSize > 0 && _expectedFileSize < static_cast<ByteCount::SizeType>(_dnlNow);
 
    // percentage:
    if ( _dnlTotal )
      _dnlPercent = int( _dnlNow * 100 / _dnlTotal );
 
    // download rates:
    _drateTotal = double(_dnlNow) / std::max( int(now - _timeStart), 1 );
 
    if ( _timeLast < now )
    {
      _drateLast = double(_dnlNow - _dnlLast) / int(now - _timeLast);
      // start new period
      _timeLast  = now;
      _dnlLast   = _dnlNow;
    }
    else if ( _timeStart == _timeLast )
      _drateLast = _drateTotal;
  }
 
  int ProgressData::reportProgress() const
  {
    if ( _fileSizeExceeded )
      return 1;
    if ( _timeoutReached )
      return 1; // no-data timeout
    if ( report && !(*report)->progress( _dnlPercent, _url, _drateTotal, _drateLast ) )
      return 1; // user requested abort
    return 0;
  }
 
  const char * anonymousIdHeader()
  {
    // we need to add the release and identifier to the
    // agent string.
    // The target could be not initialized, and then this information
    // is guessed.
    // bsc#1212187: HTTP/2 RFC 9113 forbids fields ending with a space
    static const std::string _value( str::trim( str::form(
      "X-ZYpp-AnonymousId: %s",
      Target::anonymousUniqueId( Pathname()/*guess root*/ ).c_str()
    )));
    return _value.c_str();
  }
 
  const char * distributionFlavorHeader()
  {
    // we need to add the release and identifier to the
    // agent string.
    // The target could be not initialized, and then this information
    // is guessed.
    // bsc#1212187: HTTP/2 RFC 9113 forbids fields ending with a space
    static const std::string _value( str::trim( str::form(
      "X-ZYpp-DistributionFlavor: %s",
      Target::distributionFlavor( Pathname()/*guess root*/ ).c_str()
    )));
    return _value.c_str();
  }
 
  const char * agentString()
  {
    // we need to add the release and identifier to the
    // agent string.
    // The target could be not initialized, and then this information
    // is guessed.
    // bsc#1212187: HTTP/2 RFC 9113 forbids fields ending with a space
    static const std::string _value( str::trim( str::form(
      "ZYpp " LIBZYPP_VERSION_STRING " (curl %s) %s"
      , curl_version_info(CURLVERSION_NOW)->version
      , Target::targetDistribution( Pathname()/*guess root*/ ).c_str()
    )));
    return _value.c_str();
  }
 
  class MediaCurlExceptionMayRetryInternaly : public media::MediaCurlException
  {
  public:
    MediaCurlExceptionMayRetryInternaly( const Url & url_r,
                                         const std::string & err_r,
                                         const std::string & msg_r )
    : media::MediaCurlException( url_r, err_r, msg_r )
    {}
    //~MediaCurlExceptionMayRetryInternaly() noexcept {}
  };
 
}
 
 
using namespace internal;
using namespace zypp::base;
 
namespace zypp {
 
  namespace media {
 
Pathname MediaCurl::_cookieFile = "/var/lib/YaST2/cookies";
 
// we use this define to unbloat code as this C setting option
// and catching exception is done frequently.
#define SET_OPTION(opt,val) do { \
    ret = curl_easy_setopt ( _curl, opt, val ); \
    if ( ret != 0) { \
      ZYPP_THROW(MediaCurlSetOptException(_url, _curlError)); \
    } \
  } while ( false )
 
#define SET_OPTION_OFFT(opt,val) SET_OPTION(opt,(curl_off_t)val)
#define SET_OPTION_LONG(opt,val) SET_OPTION(opt,(long)val)
#define SET_OPTION_VOID(opt,val) SET_OPTION(opt,(void*)val)
 
MediaCurl::MediaCurl( const Url &      url_r,
                      const Pathname & attach_point_hint_r )
    : MediaNetworkCommonHandler( url_r, attach_point_hint_r,
                                 "/", // urlpath at attachpoint
                                 true ), // does_download
      _curl( NULL ),
      _customHeaders(0L)
{
  _curlError[0] = '\0';
 
  MIL << "MediaCurl::MediaCurl(" << url_r << ", " << attach_point_hint_r << ")" << endl;
 
  globalInitCurlOnce();
 
  if( !attachPoint().empty())
  {
    PathInfo ainfo(attachPoint());
    Pathname apath(attachPoint() + "XXXXXX");
    char    *atemp = ::strdup( apath.asString().c_str());
    char    *atest = NULL;
    if( !ainfo.isDir() || !ainfo.userMayRWX() ||
         atemp == NULL || (atest=::mkdtemp(atemp)) == NULL)
    {
      WAR << "attach point " << ainfo.path()
          << " is not useable for " << url_r.getScheme() << endl;
      setAttachPoint("", true);
    }
    else if( atest != NULL)
      ::rmdir(atest);
 
    if( atemp != NULL)
      ::free(atemp);
  }
}
 
Url MediaCurl::clearQueryString(const Url &url) const
{
  return internal::clearQueryString(url);
}
 
void MediaCurl::setCookieFile( const Pathname &fileName )
{
  _cookieFile = fileName;
}
 
 
void MediaCurl::checkProtocol(const Url &url) const
{
  curl_version_info_data *curl_info = NULL;
  curl_info = curl_version_info(CURLVERSION_NOW);
  // curl_info does not need any free (is static)
  if (curl_info->protocols)
  {
    const char * const *proto;
    std::string        scheme( url.getScheme());
    bool               found = false;
    for(proto=curl_info->protocols; !found && *proto; ++proto)
    {
      if( scheme == std::string((const char *)*proto))
        found = true;
    }
    if( !found)
    {
      std::string msg("Unsupported protocol '");
      msg += scheme;
      msg += "'";
      ZYPP_THROW(MediaBadUrlException(_url, msg));
    }
  }
}
 
void MediaCurl::setupEasy()
{
  ::internal::setupZYPP_MEDIA_CURL_DEBUG( _curl );
 
  curl_easy_setopt(_curl, CURLOPT_HEADERFUNCTION, log_redirects_curl);
  curl_easy_setopt(_curl, CURLOPT_HEADERDATA, &_lastRedirect);
  CURLcode ret = curl_easy_setopt( _curl, CURLOPT_ERRORBUFFER, _curlError );
  if ( ret != 0 ) {
    ZYPP_THROW(MediaCurlSetOptException(_url, "Error setting error buffer"));
  }
 
  SET_OPTION(CURLOPT_FAILONERROR, 1L);
  SET_OPTION(CURLOPT_NOSIGNAL, 1L);
 
  // create non persistant settings
  // so that we don't add headers twice
  TransferSettings vol_settings(_settings);
 
  // add custom headers for download.opensuse.org (bsc#955801)
  if ( _url.getHost() == "download.opensuse.org" )
  {
    vol_settings.addHeader(anonymousIdHeader());
    vol_settings.addHeader(distributionFlavorHeader());
  }
  vol_settings.addHeader("Pragma:");
 
  _settings.setUserAgentString(agentString());
 
  // fill some settings from url query parameters
  try
  {
      fillSettingsFromUrl(_url, _settings);
  }
  catch ( const MediaException &e )
  {
      disconnectFrom();
      ZYPP_RETHROW(e);
  }
  // if the proxy was not set (or explicitly unset) by url, then look...
  if ( _settings.proxy().empty() )
  {
      // ...at the system proxy settings
      fillSettingsSystemProxy(_url, _settings);
  }
 
  switch ( env::ZYPP_MEDIA_CURL_IPRESOLVE() )
  {
    case 4: SET_OPTION(CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4); break;
    case 6: SET_OPTION(CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V6); break;
  }
 
  SET_OPTION(CURLOPT_CONNECTTIMEOUT, _settings.connectTimeout());
  // If a transfer timeout is set, also set CURLOPT_TIMEOUT to an upper limit
  // just in case curl does not trigger its progress callback frequently
  // enough.
  if ( _settings.timeout() )
  {
    SET_OPTION(CURLOPT_TIMEOUT, 3600L);
  }
 
  // follow any Location: header that the server sends as part of
  // an HTTP header (#113275)
  SET_OPTION(CURLOPT_FOLLOWLOCATION, 1L);
  // 3 redirects seem to be too few in some cases (bnc #465532)
  SET_OPTION(CURLOPT_MAXREDIRS, 6L);
 
  if ( _url.getScheme() == "https" )
  {
    // restrict following of redirections from https to https only
    // but be less restrictive for d.o.o
    bool allowHttp = ( _url.getHost() == "download.opensuse.org" );
    if ( :: internal::setCurlRedirProtocols ( _curl, allowHttp ) != CURLE_OK ) {
      ZYPP_THROW(MediaCurlSetOptException(_url, _curlError));
    }
 
    if( _settings.verifyPeerEnabled() ||
        _settings.verifyHostEnabled() )
    {
      SET_OPTION(CURLOPT_CAPATH, _settings.certificateAuthoritiesPath().c_str());
    }
 
    if( ! _settings.clientCertificatePath().empty() )
    {
      SET_OPTION(CURLOPT_SSLCERT, _settings.clientCertificatePath().c_str());
    }
    if( ! _settings.clientKeyPath().empty() )
    {
      SET_OPTION(CURLOPT_SSLKEY, _settings.clientKeyPath().c_str());
    }
 
#ifdef CURLSSLOPT_ALLOW_BEAST
    // see bnc#779177
    ret = curl_easy_setopt( _curl, CURLOPT_SSL_OPTIONS, CURLSSLOPT_ALLOW_BEAST );
    if ( ret != 0 ) {
      disconnectFrom();
      ZYPP_THROW(MediaCurlSetOptException(_url, _curlError));
    }
#endif
    SET_OPTION(CURLOPT_SSL_VERIFYPEER, _settings.verifyPeerEnabled() ? 1L : 0L);
    SET_OPTION(CURLOPT_SSL_VERIFYHOST, _settings.verifyHostEnabled() ? 2L : 0L);
    // bnc#903405 - POODLE: libzypp should only talk TLS
    SET_OPTION(CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);
  }
 
  SET_OPTION(CURLOPT_USERAGENT, _settings.userAgentString().c_str() );
 
  /* Fixes bsc#1174011 "auth=basic ignored in some cases"
       * We should proactively add the password to the request if basic auth is configured
       * and a password is available in the credentials but not in the URL.
       *
       * We will be a bit paranoid here and require that the URL has a user embedded, otherwise we go the default route
       * and ask the server first about the auth method
       */
  if ( _settings.authType() == "basic"
       && _settings.username().size()
       && !_settings.password().size() ) {
 
    CredentialManager cm(CredManagerOptions(ZConfig::instance().repoManagerRoot()));
    const auto cred = cm.getCred( _url );
    if ( cred && cred->valid() ) {
      if ( !_settings.username().size() )
        _settings.setUsername(cred->username());
      _settings.setPassword(cred->password());
    }
  }
 
  /*---------------------------------------------------------------*
   CURLOPT_USERPWD: [user name]:[password]
 
   Url::username/password -> CURLOPT_USERPWD
   If not provided, anonymous FTP identification
   *---------------------------------------------------------------*/
 
  if ( _settings.userPassword().size() )
  {
    SET_OPTION(CURLOPT_USERPWD, _settings.userPassword().c_str());
    std::string use_auth = _settings.authType();
    if (use_auth.empty())
      use_auth = "digest,basic";        // our default
    long auth = CurlAuthData::auth_type_str2long(use_auth);
    if( auth != CURLAUTH_NONE)
    {
      DBG << "Enabling HTTP authentication methods: " << use_auth
          << " (CURLOPT_HTTPAUTH=" << auth << ")" << std::endl;
      SET_OPTION(CURLOPT_HTTPAUTH, auth);
    }
  }
 
  if ( _settings.proxyEnabled() && ! _settings.proxy().empty() )
  {
    DBG << "Proxy: '" << _settings.proxy() << "'" << endl;
    SET_OPTION(CURLOPT_PROXY, _settings.proxy().c_str());
    SET_OPTION(CURLOPT_PROXYAUTH, CURLAUTH_BASIC|CURLAUTH_DIGEST|CURLAUTH_NTLM );
    /*---------------------------------------------------------------*
     *    CURLOPT_PROXYUSERPWD: [user name]:[password]
     *
     * Url::option(proxyuser and proxypassword) -> CURLOPT_PROXYUSERPWD
     *  If not provided, $HOME/.curlrc is evaluated
     *---------------------------------------------------------------*/
 
    std::string proxyuserpwd = _settings.proxyUserPassword();
 
    if ( proxyuserpwd.empty() )
    {
      CurlConfig curlconf;
      CurlConfig::parseConfig(curlconf); // parse ~/.curlrc
      if ( curlconf.proxyuserpwd.empty() )
        DBG << "Proxy: ~/.curlrc does not contain the proxy-user option" << endl;
      else
      {
        proxyuserpwd = curlconf.proxyuserpwd;
        DBG << "Proxy: using proxy-user from ~/.curlrc" << endl;
      }
    }
    else
    {
      DBG << "Proxy: using provided proxy-user '" << _settings.proxyUsername() << "'" << endl;
    }
 
    if ( ! proxyuserpwd.empty() )
    {
      SET_OPTION(CURLOPT_PROXYUSERPWD, curlUnEscape( proxyuserpwd ).c_str());
    }
  }
#if CURLVERSION_AT_LEAST(7,19,4)
  else if ( _settings.proxy() == EXPLICITLY_NO_PROXY )
  {
    // Explicitly disabled in URL (see fillSettingsFromUrl()).
    // This should also prevent libcurl from looking into the environment.
    DBG << "Proxy: explicitly NOPROXY" << endl;
    SET_OPTION(CURLOPT_NOPROXY, "*");
  }
#endif
  else
  {
    DBG << "Proxy: not explicitly set" << endl;
    DBG << "Proxy: libcurl may look into the environment" << endl;
  }
 
  if ( _settings.minDownloadSpeed() != 0 )
  {
      SET_OPTION(CURLOPT_LOW_SPEED_LIMIT, _settings.minDownloadSpeed());
      // default to 10 seconds at low speed
      SET_OPTION(CURLOPT_LOW_SPEED_TIME, 60L);
  }
 
#if CURLVERSION_AT_LEAST(7,15,5)
  if ( _settings.maxDownloadSpeed() != 0 )
      SET_OPTION_OFFT(CURLOPT_MAX_RECV_SPEED_LARGE, _settings.maxDownloadSpeed());
#endif
 
  /*---------------------------------------------------------------*
   *---------------------------------------------------------------*/
 
  _currentCookieFile = _cookieFile.asString();
  if ( ::geteuid() == 0 || PathInfo(_currentCookieFile).owner() == ::geteuid() )
    filesystem::assert_file_mode( _currentCookieFile, 0600 );
  if ( str::strToBool( _url.getQueryParam( "cookies" ), true ) )
    SET_OPTION(CURLOPT_COOKIEFILE, _currentCookieFile.c_str() );
  else
    MIL << "No cookies requested" << endl;
  SET_OPTION(CURLOPT_COOKIEJAR, _currentCookieFile.c_str() );
  SET_OPTION(CURLOPT_XFERINFOFUNCTION, &progressCallback );
  SET_OPTION(CURLOPT_NOPROGRESS, 0L);
 
#if CURLVERSION_AT_LEAST(7,18,0)
  // bnc #306272
  SET_OPTION(CURLOPT_PROXY_TRANSFER_MODE, 1L );
#endif
  // Append settings custom headers to curl.
  // TransferSettings assert strings are trimmed (HTTP/2 RFC 9113)
  for ( const auto &header : vol_settings.headers() ) {
    _customHeaders = curl_slist_append(_customHeaders, header.c_str());
    if ( !_customHeaders )
      ZYPP_THROW(MediaCurlInitException(_url));
  }
  SET_OPTION(CURLOPT_HTTPHEADER, _customHeaders);
}
 
 
 
void MediaCurl::attachTo (bool next)
{
  if ( next )
    ZYPP_THROW(MediaNotSupportedException(_url));
 
  if ( !_url.isValid() )
    ZYPP_THROW(MediaBadUrlException(_url));
 
  checkProtocol(_url);
  if( !isUseableAttachPoint( attachPoint() ) )
  {
    setAttachPoint( createAttachPoint(), true );
  }
 
  disconnectFrom(); // clean _curl if needed
  _curl = curl_easy_init();
  if ( !_curl ) {
    ZYPP_THROW(MediaCurlInitException(_url));
  }
  try
    {
      setupEasy();
    }
  catch (Exception & ex)
    {
      disconnectFrom();
      ZYPP_RETHROW(ex);
    }
 
  // FIXME: need a derived class to propelly compare url's
  MediaSourceRef media( new MediaSource(_url.getScheme(), _url.asString()));
  setMediaSource(media);
}
 
bool
MediaCurl::checkAttachPoint(const Pathname &apoint) const
{
  return MediaHandler::checkAttachPoint( apoint, true, true);
}
 
 
void MediaCurl::disconnectFrom()
{
  if ( _customHeaders )
  {
    curl_slist_free_all(_customHeaders);
    _customHeaders = 0L;
  }
 
  if ( _curl )
  {
    // bsc#1201092: Strange but within global_dtors we may exceptions here.
    try { curl_easy_cleanup( _curl ); }
    catch (...) { ; }
    _curl = NULL;
  }
}
 
 
void MediaCurl::releaseFrom( const std::string & ejectDev )
{
  disconnect();
}
 
 
void MediaCurl::getFile( const OnMediaLocation &file ) const
{
    // Use absolute file name to prevent access of files outside of the
    // hierarchy below the attach point.
    getFileCopy( file, localPath(file.filename()).absolutename() );
}
 
 
void MediaCurl::getFileCopy( const OnMediaLocation & srcFile , const Pathname & target ) const
{
 
  const auto &filename = srcFile.filename();
 
  // Optional files will send no report until data are actually received (we know it exists).
  OptionalDownloadProgressReport reportfilter( srcFile.optional() );
  callback::SendReport<DownloadProgressReport> report;
 
  Url fileurl(getFileUrl(filename));
 
  bool firstAuth = true;  // bsc#1210870: authenticate must not return stored credentials more than once.
  unsigned internalTry = 0;
  static constexpr unsigned maxInternalTry = 3;
 
  do
  {
    try
    {
      doGetFileCopy( srcFile, target, report );
      break;  // success!
    }
    // retry with proper authentication data
    catch (MediaUnauthorizedException & ex_r)
    {
      if ( authenticate(ex_r.hint(), firstAuth) ) {
        firstAuth = false;  // must not return stored credentials again
        continue; // retry
      }
 
      report->finish(fileurl, zypp::media::DownloadProgressReport::ACCESS_DENIED, ex_r.asUserHistory());
      ZYPP_RETHROW(ex_r);
    }
    // unexpected exception
    catch (MediaException & excpt_r)
    {
      if ( typeid(excpt_r) == typeid( MediaCurlExceptionMayRetryInternaly ) ) {
        ++internalTry;
        if ( internalTry < maxInternalTry ) {
          // just report (NO_ERROR); no interactive request to the user
          report->problem(fileurl, media::DownloadProgressReport::NO_ERROR, excpt_r.asUserHistory()+_("Will try again..."));
          continue; // retry
        }
        excpt_r.addHistory( str::Format(_("Giving up after %1% attempts.")) % maxInternalTry );
      }
 
      media::DownloadProgressReport::Error reason = media::DownloadProgressReport::ERROR;
      if( typeid(excpt_r) == typeid( media::MediaFileNotFoundException )  ||
          typeid(excpt_r) == typeid( media::MediaNotAFileException ) )
      {
        reason = media::DownloadProgressReport::NOT_FOUND;
      }
      report->finish(fileurl, reason, excpt_r.asUserHistory());
      ZYPP_RETHROW(excpt_r);
    }
  }
  while ( true );
  report->finish(fileurl, zypp::media::DownloadProgressReport::NO_ERROR, "");
}
 
 
bool MediaCurl::getDoesFileExist( const Pathname & filename ) const
{
  bool retry = false;
 
  do
  {
    try
    {
      return doGetDoesFileExist( filename );
    }
    // authentication problem, retry with proper authentication data
    catch (MediaUnauthorizedException & ex_r)
    {
      if(authenticate(ex_r.hint(), !retry))
        retry = true;
      else
        ZYPP_RETHROW(ex_r);
    }
    // unexpected exception
    catch (MediaException & excpt_r)
    {
      ZYPP_RETHROW(excpt_r);
    }
  }
  while (retry);
 
  return false;
}
 
 
void MediaCurl::evaluateCurlCode(const Pathname &filename,
                                  CURLcode code,
                                  bool timeout_reached) const
{
  if ( code != 0 )
  {
    Url url;
    if (filename.empty())
      url = _url;
    else
      url = getFileUrl(filename);
 
    std::string err;
    {
      switch ( code )
      {
      case CURLE_UNSUPPORTED_PROTOCOL:
          err = " Unsupported protocol";
          if ( !_lastRedirect.empty() )
          {
            err += " or redirect (";
            err += _lastRedirect;
            err += ")";
          }
          break;
      case CURLE_URL_MALFORMAT:
      case CURLE_URL_MALFORMAT_USER:
          err = " Bad URL";
          break;
      case CURLE_LOGIN_DENIED:
          ZYPP_THROW(
              MediaUnauthorizedException(url, "Login failed.", _curlError, ""));
          break;
      case CURLE_HTTP_RETURNED_ERROR:
      {
        long httpReturnCode = 0;
        CURLcode infoRet = curl_easy_getinfo( _curl,
                                              CURLINFO_RESPONSE_CODE,
                                              &httpReturnCode );
        if ( infoRet == CURLE_OK )
        {
          std::string msg = "HTTP response: " + str::numstring( httpReturnCode );
          switch ( httpReturnCode )
          {
          case 401:
          {
            std::string auth_hint = getAuthHint();
 
            DBG << msg << " Login failed (URL: " << url.asString() << ")" << std::endl;
            DBG << "MediaUnauthorizedException auth hint: '" << auth_hint << "'" << std::endl;
 
            ZYPP_THROW(MediaUnauthorizedException(
                           url, "Login failed.", _curlError, auth_hint
                           ));
          }
 
          case 502: // bad gateway (bnc #1070851)
          case 503: // service temporarily unavailable (bnc #462545)
            ZYPP_THROW(MediaTemporaryProblemException(url));
          case 504: // gateway timeout
            ZYPP_THROW(MediaTimeoutException(url));
          case 403:
          {
            std::string msg403;
            if ( url.getHost().find(".suse.com") != std::string::npos )
              msg403 = _("Visit the SUSE Customer Center to check whether your registration is valid and has not expired.");
            else if (url.asString().find("novell.com") != std::string::npos)
              msg403 = _("Visit the Novell Customer Center to check whether your registration is valid and has not expired.");
            ZYPP_THROW(MediaForbiddenException(url, msg403));
          }
          case 404:
          case 410:
              ZYPP_THROW(MediaFileNotFoundException(_url, filename));
          }
 
          DBG << msg << " (URL: " << url.asString() << ")" << std::endl;
          ZYPP_THROW(MediaCurlException(url, msg, _curlError));
        }
        else
        {
          std::string msg = "Unable to retrieve HTTP response:";
          DBG << msg << " (URL: " << url.asString() << ")" << std::endl;
          ZYPP_THROW(MediaCurlException(url, msg, _curlError));
        }
      }
      break;
      case CURLE_FTP_COULDNT_RETR_FILE:
#if CURLVERSION_AT_LEAST(7,16,0)
      case CURLE_REMOTE_FILE_NOT_FOUND:
#endif
      case CURLE_FTP_ACCESS_DENIED:
      case CURLE_TFTP_NOTFOUND:
        err = "File not found";
        ZYPP_THROW(MediaFileNotFoundException(_url, filename));
        break;
      case CURLE_BAD_PASSWORD_ENTERED:
      case CURLE_FTP_USER_PASSWORD_INCORRECT:
          err = "Login failed";
          break;
      case CURLE_COULDNT_RESOLVE_PROXY:
      case CURLE_COULDNT_RESOLVE_HOST:
      case CURLE_COULDNT_CONNECT:
      case CURLE_FTP_CANT_GET_HOST:
        err = "Connection failed";
        break;
      case CURLE_WRITE_ERROR:
        err = "Write error";
        break;
      case CURLE_PARTIAL_FILE:
      case CURLE_OPERATION_TIMEDOUT:
        timeout_reached = true; // fall though to TimeoutException
        // fall though...
      case CURLE_ABORTED_BY_CALLBACK:
         if( timeout_reached )
        {
          err  = "Timeout reached";
          ZYPP_THROW(MediaTimeoutException(url));
        }
        else
        {
          err = "User abort";
        }
        break;
 
      // Attempt to work around certain issues by autoretry in MediaCurl::getFileCopy
      case CURLE_HTTP2:
      case CURLE_HTTP2_STREAM:
        err = "Curl error " + str::numstring( code );
        ZYPP_THROW(MediaCurlExceptionMayRetryInternaly(url, err, _curlError));
        break;
 
      default:
        err = "Curl error " + str::numstring( code );
        break;
      }
 
      // uhm, no 0 code but unknown curl exception
      ZYPP_THROW(MediaCurlException(url, err, _curlError));
    }
  }
  else
  {
    // actually the code is 0, nothing happened
  }
}
 
 
bool MediaCurl::doGetDoesFileExist( const Pathname & filename ) const
{
  DBG << filename.asString() << endl;
 
  if(!_url.isValid())
    ZYPP_THROW(MediaBadUrlException(_url));
 
  if(_url.getHost().empty())
    ZYPP_THROW(MediaBadUrlEmptyHostException(_url));
 
  Url url(getFileUrl(filename));
 
  DBG << "URL: " << url.asString() << endl;
    // Use URL without options and without username and passwd
    // (some proxies dislike them in the URL).
    // Curl seems to need the just scheme, hostname and a path;
    // the rest was already passed as curl options (in attachTo).
  Url curlUrl( clearQueryString(url) );
 
  //
    // See also Bug #154197 and ftp url definition in RFC 1738:
    // The url "ftp://user@host/foo/bar/file" contains a path,
    // that is relative to the user's home.
    // The url "ftp://user@host//foo/bar/file" (or also with
    // encoded slash as %2f) "ftp://user@host/%2ffoo/bar/file"
    // contains an absolute path.
  //
  _lastRedirect.clear();
  std::string urlBuffer( curlUrl.asString());
  CURLcode ret = curl_easy_setopt( _curl, CURLOPT_URL,
                                   urlBuffer.c_str() );
  if ( ret != 0 ) {
    ZYPP_THROW(MediaCurlSetOptException(url, _curlError));
  }
 
  // If no head requests allowed (?head_requests=no):
  // Instead of returning no data with NOBODY, we return
  // little data, that works with broken servers, and
  // works for ftp as well, because retrieving only headers
  // ftp will return always OK code ?
  // See http://curl.haxx.se/docs/knownbugs.html #58
  struct TempSetHeadRequest
  {
    TempSetHeadRequest( CURL * curl_r, bool doHttpHeadRequest_r )
    : _curl { curl_r }
    , _doHttpHeadRequest { doHttpHeadRequest_r }
    {
      if ( _doHttpHeadRequest ) {
        curl_easy_setopt( _curl, CURLOPT_NOBODY, 1L );
      } else {
        curl_easy_setopt( _curl, CURLOPT_RANGE, "0-1" );
      }
    }
    ~TempSetHeadRequest() {
      if ( _doHttpHeadRequest ) {
        curl_easy_setopt( _curl, CURLOPT_NOBODY, 0L);
        /* yes, this is why we never got to get NOBODY working before,
         because setting it changes this option too, and we also*
         need to reset it
         See: http://curl.haxx.se/mail/archive-2005-07/0073.html
         */
        curl_easy_setopt( _curl, CURLOPT_HTTPGET, 1L );
      } else {
        curl_easy_setopt( _curl, CURLOPT_RANGE, NULL );
      }
    }
  private:
    CURL * _curl;
    bool   _doHttpHeadRequest;
  } _guard( _curl, (_url.getScheme() == "http" || _url.getScheme() == "https") && _settings.headRequestsAllowed() );
 
 
  AutoFILE file { ::fopen( "/dev/null", "w" ) };
  if ( !file ) {
      ERR << "fopen failed for /dev/null" << endl;
      ZYPP_THROW(MediaWriteException("/dev/null"));
  }
 
  ret = curl_easy_setopt( _curl, CURLOPT_WRITEDATA, (*file) );
  if ( ret != 0 ) {
    ZYPP_THROW(MediaCurlSetOptException(url, _curlError));
  }
 
  CURLcode ok = executeCurl();
  MIL << "perform code: " << ok << " [ " << curl_easy_strerror(ok) << " ]" << endl;
 
  // as we are not having user interaction, the user can't cancel
  // the file existence checking, a callback or timeout return code
  // will be always a timeout.
  try {
      evaluateCurlCode( filename, ok, true /* timeout */);
  }
  catch ( const MediaFileNotFoundException &e ) {
      // if the file did not exist then we can return false
      return false;
  }
  catch ( const MediaException &e ) {
      // some error, we are not sure about file existence, rethrw
      ZYPP_RETHROW(e);
  }
  // exists
  return ( ok == CURLE_OK );
}
 
 
void MediaCurl::doGetFileCopy( const OnMediaLocation &srcFile , const Pathname & target, callback::SendReport<DownloadProgressReport> & report, RequestOptions options ) const
{
    Pathname dest = target.absolutename();
    if( assert_dir( dest.dirname() ) )
    {
      DBG << "assert_dir " << dest.dirname() << " failed" << endl;
      ZYPP_THROW( MediaSystemException(getFileUrl(srcFile.filename()), "System error on " + dest.dirname().asString()) );
    }
 
    ManagedFile destNew { target.extend( ".new.zypp.XXXXXX" ) };
    AutoFILE file;
    {
      AutoFREE<char> buf { ::strdup( (*destNew).c_str() ) };
      if( ! buf )
      {
        ERR << "out of memory for temp file name" << endl;
        ZYPP_THROW(MediaSystemException(getFileUrl(srcFile.filename()), "out of memory for temp file name"));
      }
 
      AutoFD tmp_fd { ::mkostemp( buf, O_CLOEXEC ) };
      if( tmp_fd == -1 )
      {
        ERR << "mkstemp failed for file '" << destNew << "'" << endl;
        ZYPP_THROW(MediaWriteException(destNew));
      }
      destNew = ManagedFile( (*buf), filesystem::unlink );
 
      file = ::fdopen( tmp_fd, "we" );
      if ( ! file )
      {
        ERR << "fopen failed for file '" << destNew << "'" << endl;
        ZYPP_THROW(MediaWriteException(destNew));
      }
      tmp_fd.resetDispose();    // don't close it here! ::fdopen moved ownership to file
    }
 
    DBG << "dest: " << dest << endl;
    DBG << "temp: " << destNew << endl;
 
    // set IFMODSINCE time condition (no download if not modified)
    if( PathInfo(target).isExist() && !(options & OPTION_NO_IFMODSINCE) )
    {
      curl_easy_setopt(_curl, CURLOPT_TIMECONDITION, CURL_TIMECOND_IFMODSINCE);
      curl_easy_setopt(_curl, CURLOPT_TIMEVALUE, (long)PathInfo(target).mtime());
    }
    else
    {
      curl_easy_setopt(_curl, CURLOPT_TIMECONDITION, CURL_TIMECOND_NONE);
      curl_easy_setopt(_curl, CURLOPT_TIMEVALUE, 0L);
    }
    try
    {
      doGetFileCopyFile( srcFile, dest, file, report, options);
    }
    catch (Exception &e)
    {
      curl_easy_setopt(_curl, CURLOPT_TIMECONDITION, CURL_TIMECOND_NONE);
      curl_easy_setopt(_curl, CURLOPT_TIMEVALUE, 0L);
      ZYPP_RETHROW(e);
    }
 
    long httpReturnCode = 0;
    CURLcode infoRet = curl_easy_getinfo(_curl,
                                         CURLINFO_RESPONSE_CODE,
                                         &httpReturnCode);
    bool modified = true;
    if (infoRet == CURLE_OK)
    {
      DBG << "HTTP response: " + str::numstring(httpReturnCode);
      if ( httpReturnCode == 304
           || ( httpReturnCode == 213 && (_url.getScheme() == "ftp" || _url.getScheme() == "tftp") ) ) // not modified
      {
        DBG << " Not modified.";
        modified = false;
      }
      DBG << endl;
    }
    else
    {
      WAR << "Could not get the response code." << endl;
    }
 
    if (modified || infoRet != CURLE_OK)
    {
      // apply umask
      if ( ::fchmod( ::fileno(file), filesystem::applyUmaskTo( 0644 ) ) )
      {
        ERR << "Failed to chmod file " << destNew << endl;
      }
 
      file.resetDispose();      // we're going to close it manually here
      if ( ::fclose( file ) )
      {
        ERR << "Fclose failed for file '" << destNew << "'" << endl;
        ZYPP_THROW(MediaWriteException(destNew));
      }
 
      // move the temp file into dest
      if ( rename( destNew, dest ) != 0 ) {
        ERR << "Rename failed" << endl;
        ZYPP_THROW(MediaWriteException(dest));
      }
      destNew.resetDispose();   // no more need to unlink it
    }
 
    DBG << "done: " << PathInfo(dest) << endl;
}
 
 
void MediaCurl::doGetFileCopyFile( const OnMediaLocation & srcFile, const Pathname & dest, FILE *file, callback::SendReport<DownloadProgressReport> & report, RequestOptions options ) const
{
    DBG << srcFile.filename().asString() << endl;
 
    if(!_url.isValid())
      ZYPP_THROW(MediaBadUrlException(_url));
 
    if(_url.getHost().empty())
      ZYPP_THROW(MediaBadUrlEmptyHostException(_url));
 
    Url url(getFileUrl(srcFile.filename()));
 
    DBG << "URL: " << url.asString() << endl;
    // Use URL without options and without username and passwd
    // (some proxies dislike them in the URL).
    // Curl seems to need the just scheme, hostname and a path;
    // the rest was already passed as curl options (in attachTo).
    Url curlUrl( clearQueryString(url) );
 
    //
    // See also Bug #154197 and ftp url definition in RFC 1738:
    // The url "ftp://user@host/foo/bar/file" contains a path,
    // that is relative to the user's home.
    // The url "ftp://user@host//foo/bar/file" (or also with
    // encoded slash as %2f) "ftp://user@host/%2ffoo/bar/file"
    // contains an absolute path.
    //
    _lastRedirect.clear();
    std::string urlBuffer( curlUrl.asString());
    CURLcode ret = curl_easy_setopt( _curl, CURLOPT_URL,
                                     urlBuffer.c_str() );
    if ( ret != 0 ) {
      ZYPP_THROW(MediaCurlSetOptException(url, _curlError));
    }
 
    ret = curl_easy_setopt( _curl, CURLOPT_WRITEDATA, file );
    if ( ret != 0 ) {
      ZYPP_THROW(MediaCurlSetOptException(url, _curlError));
    }
 
    // Set callback and perform.
    internal::ProgressData progressData(_curl, _settings.timeout(), url, srcFile.downloadSize(), &report);
    if (!(options & OPTION_NO_REPORT_START))
      report->start(url, dest);
    if ( curl_easy_setopt( _curl, CURLOPT_PROGRESSDATA, &progressData ) != 0 ) {
      WAR << "Can't set CURLOPT_PROGRESSDATA: " << _curlError << endl;;
    }
 
    ret = executeCurl();
#if CURLVERSION_AT_LEAST(7,19,4)
    // bnc#692260: If the client sends a request with an If-Modified-Since header
    // with a future date for the server, the server may respond 200 sending a
    // zero size file.
    // curl-7.19.4 introduces CURLINFO_CONDITION_UNMET to check this condition.
    if ( ftell(file) == 0 && ret == 0 )
    {
      long httpReturnCode = 33;
      if ( curl_easy_getinfo( _curl, CURLINFO_RESPONSE_CODE, &httpReturnCode ) == CURLE_OK && httpReturnCode == 200 )
      {
        long conditionUnmet = 33;
        if ( curl_easy_getinfo( _curl, CURLINFO_CONDITION_UNMET, &conditionUnmet ) == CURLE_OK && conditionUnmet )
        {
          WAR << "TIMECONDITION unmet - retry without." << endl;
          curl_easy_setopt(_curl, CURLOPT_TIMECONDITION, CURL_TIMECOND_NONE);
          curl_easy_setopt(_curl, CURLOPT_TIMEVALUE, 0L);
          ret = executeCurl();
        }
      }
    }
#endif
 
    if ( curl_easy_setopt( _curl, CURLOPT_PROGRESSDATA, NULL ) != 0 ) {
      WAR << "Can't unset CURLOPT_PROGRESSDATA: " << _curlError << endl;;
    }
 
    if ( ret != 0 )
    {
      ERR << "curl error: " << ret << ": " << _curlError
          << ", temp file size " << ftell(file)
          << " bytes." << endl;
 
      // the timeout is determined by the progress data object
      // which holds whether the timeout was reached or not,
      // otherwise it would be a user cancel
      try {
 
        if ( progressData.fileSizeExceeded() )
          ZYPP_THROW(MediaFileSizeExceededException(url, progressData.expectedFileSize()));
 
        evaluateCurlCode( srcFile.filename(), ret, progressData.timeoutReached() );
      }
      catch ( const MediaException &e ) {
        // some error, we are not sure about file existence, rethrw
        ZYPP_RETHROW(e);
      }
    }
}
 
 
void MediaCurl::getDir( const Pathname & dirname, bool recurse_r ) const
{
  filesystem::DirContent content;
  getDirInfo( content, dirname, /*dots*/false );
 
  for ( filesystem::DirContent::const_iterator it = content.begin(); it != content.end(); ++it ) {
      Pathname filename = dirname + it->name;
      int res = 0;
 
      switch ( it->type ) {
      case filesystem::FT_NOT_AVAIL: // old directory.yast contains no typeinfo at all
      case filesystem::FT_FILE:
        getFile( OnMediaLocation( filename ) );
        break;
      case filesystem::FT_DIR: // newer directory.yast contain at least directory info
        if ( recurse_r ) {
          getDir( filename, recurse_r );
        } else {
          res = assert_dir( localPath( filename ) );
          if ( res ) {
            WAR << "Ignore error (" << res <<  ") on creating local directory '" << localPath( filename ) << "'" << endl;
          }
        }
        break;
      default:
        // don't provide devices, sockets, etc.
        break;
      }
  }
}
 
 
void MediaCurl::getDirInfo( std::list<std::string> & retlist,
                               const Pathname & dirname, bool dots ) const
{
  getDirectoryYast( retlist, dirname, dots );
}
 
 
void MediaCurl::getDirInfo( filesystem::DirContent & retlist,
                            const Pathname & dirname, bool dots ) const
{
  getDirectoryYast( retlist, dirname, dots );
}
 
//
int MediaCurl::aliveCallback( void *clientp, curl_off_t /*dltotal*/, curl_off_t dlnow, curl_off_t /*ultotal*/, curl_off_t /*ulnow*/ )
{
  internal::ProgressData *pdata = reinterpret_cast<internal::ProgressData *>( clientp );
  if( pdata )
  {
    // Do not propagate dltotal in alive callbacks. MultiCurl uses this to
    // prevent a percentage raise while downloading a metalink file. Download
    // activity however is indicated by propagating the download rate (via dlnow).
    pdata->updateStats( 0.0, dlnow );
    return pdata->reportProgress();
  }
  return 0;
}
 
int MediaCurl::progressCallback( void *clientp, curl_off_t dltotal, curl_off_t dlnow, curl_off_t ultotal, curl_off_t ulnow )
{
  internal::ProgressData *pdata = reinterpret_cast<internal::ProgressData *>( clientp );
  if( pdata )
  {
    // work around curl bug that gives us old data
    long httpReturnCode = 0;
    if ( curl_easy_getinfo( pdata->curl(), CURLINFO_RESPONSE_CODE, &httpReturnCode ) != CURLE_OK || httpReturnCode == 0 )
      return aliveCallback( clientp, dltotal, dlnow, ultotal, ulnow );
 
    pdata->updateStats( dltotal, dlnow );
    return pdata->reportProgress();
  }
  return 0;
}
 
CURL *MediaCurl::progressCallback_getcurl( void *clientp )
{
  internal::ProgressData *pdata = reinterpret_cast<internal::ProgressData *>(clientp);
  return pdata ? pdata->curl() : 0;
}
 
 
std::string MediaCurl::getAuthHint() const
{
  long auth_info = CURLAUTH_NONE;
 
  CURLcode infoRet =
    curl_easy_getinfo(_curl, CURLINFO_HTTPAUTH_AVAIL, &auth_info);
 
  if(infoRet == CURLE_OK)
  {
    return CurlAuthData::auth_type_long2str(auth_info);
  }
 
  return "";
}
 
void MediaCurl::resetExpectedFileSize(void *clientp, const ByteCount &expectedFileSize)
{
  internal::ProgressData *data = reinterpret_cast<internal::ProgressData *>(clientp);
  if ( data ) {
    data->expectedFileSize( expectedFileSize );
  }
}
 
CURLcode MediaCurl::executeCurl() const
{
  // initialize our helpers
  AutoDispose<internal::CurlPollHelper::CurlPoll> cMulti(
    internal::CurlPollHelper::CurlPoll{ curl_multi_init() }
    ,[](auto &releaseMe ){ if (releaseMe._multi) curl_multi_cleanup(releaseMe._multi); }
  );
 
  if (!cMulti->_multi)
    ZYPP_THROW(MediaCurlInitException(_url));
 
  // we could derive from that, but currently that does not make a lot of sense
  internal::CurlPollHelper _curlHelper(cMulti.value());
 
  // add the easy handle to the multi instance
  if ( curl_multi_add_handle( cMulti->_multi, _curl ) != CURLM_OK )
    ZYPP_THROW(MediaCurlException( _url, "curl_multi_add_handle", "unknown error"));
 
  // make sure the handle is cleanly removed from the multi handle
  OnScopeExit autoRemove([&](){ curl_multi_remove_handle( cMulti->_multi, _curl ); });
 
  // kickstart curl, this will cause libcurl to go over the added handles and register sockets and timeouts
  CURLMcode mcode = _curlHelper.handleTimout();
  if (mcode != CURLM_OK)
    ZYPP_THROW(MediaCurlException( _url, "curl_multi_socket_action", "unknown error"));
 
  bool canContinue = true;
  while ( canContinue ) {
 
    // copy watched sockets in case curl changes the vector as we go over the events later
    std::vector<GPollFD> requestedFds = _curlHelper.socks;
 
    int r = zypp_detail::zypp_poll( requestedFds, _curlHelper.timeout_ms.value_or( -1 ) );
    if ( r == -1 )
      ZYPP_THROW( MediaCurlException(_url, "zypp_poll() failed", "unknown error") );
 
    // run curl
    if ( r == 0 ) {
      CURLMcode mcode = _curlHelper.handleTimout();
      if (mcode != CURLM_OK)
        ZYPP_THROW(MediaCurlException(_url, "curl_multi_socket_action", "unknown error"));
    } else {
      CURLMcode mcode = _curlHelper.handleSocketActions( requestedFds );
      if (mcode != CURLM_OK)
        ZYPP_THROW(MediaCurlException(_url, "curl_multi_socket_action", "unknown error"));
    }
 
    CURLMsg *msg;
    int nqueue;
    while ((msg = curl_multi_info_read( cMulti->_multi, &nqueue)) != 0) {
        if ( msg->msg != CURLMSG_DONE  ) continue;
        if ( msg->easy_handle != _curl ) continue;
 
        return msg->data.result;
    }
  }
  return CURLE_OK;
}
 
 
bool MediaCurl::authenticate(const std::string & availAuthTypes, bool firstTry) const
{
  CredentialManager cm(CredManagerOptions(ZConfig::instance().repoManagerRoot()));
  CurlAuthData_Ptr credentials;
 
  // get stored credentials
  AuthData_Ptr cmcred = cm.getCred(_url);
 
  if (cmcred && firstTry)
  {
    credentials.reset(new CurlAuthData(*cmcred));
    DBG << "got stored credentials:" << endl << *credentials << endl;
  }
  // if not found, ask user
  else
  {
 
    CurlAuthData_Ptr curlcred;
    curlcred.reset(new CurlAuthData());
    callback::SendReport<AuthenticationReport> auth_report;
 
    // preset the username if present in current url
    if (!_url.getUsername().empty() && firstTry)
      curlcred->setUsername(_url.getUsername());
    // if CM has found some credentials, preset the username from there
    else if (cmcred)
      curlcred->setUsername(cmcred->username());
 
    // indicate we have no good credentials from CM
    cmcred.reset();
 
    std::string prompt_msg = str::Format(_("Authentication required for '%s'")) % _url.asString();
 
    // set available authentication types from the exception
    // might be needed in prompt
    curlcred->setAuthType(availAuthTypes);
 
    // ask user
    if (auth_report->prompt(_url, prompt_msg, *curlcred))
    {
      DBG << "callback answer: retry" << endl
          << "CurlAuthData: " << *curlcred << endl;
 
      if (curlcred->valid())
      {
        credentials = curlcred;
          // if (credentials->username() != _url.getUsername())
          //   _url.setUsername(credentials->username());
      }
    }
    else
    {
      DBG << "callback answer: cancel" << endl;
    }
  }
 
  // set username and password
  if (credentials)
  {
    // HACK, why is this const?
    const_cast<MediaCurl*>(this)->_settings.setUsername(credentials->username());
    const_cast<MediaCurl*>(this)->_settings.setPassword(credentials->password());
 
    // set username and password
    CURLcode ret = curl_easy_setopt(_curl, CURLOPT_USERPWD, _settings.userPassword().c_str());
    if ( ret != 0 ) ZYPP_THROW(MediaCurlSetOptException(_url, _curlError));
 
    // set available authentication types from the exception
    if (credentials->authType() == CURLAUTH_NONE)
      credentials->setAuthType(availAuthTypes);
 
    // set auth type (seems this must be set _after_ setting the userpwd)
    if (credentials->authType() != CURLAUTH_NONE)
    {
      // FIXME: only overwrite if not empty?
      const_cast<MediaCurl*>(this)->_settings.setAuthType(credentials->authTypeAsString());
      ret = curl_easy_setopt(_curl, CURLOPT_HTTPAUTH, credentials->authType());
      if ( ret != 0 ) ZYPP_THROW(MediaCurlSetOptException(_url, _curlError));
    }
 
    if (!cmcred)
    {
      credentials->setUrl(_url);
      cm.addCred(*credentials);
      cm.save();
    }
 
    return true;
  }
 
  return false;
}
 
//need a out of line definiton, otherwise vtable is emitted for every translation unit
MediaCurl::Callbacks::~Callbacks() {}
 
  } // namespace media
} // namespace zypp
//