methods/server.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 /* ######################################################################
   4
   5    HTTP and HTTPS share a lot of common code and these classes are
   6    exactly the dumping ground for this common code
   7
   8    ##################################################################### */
   9                                                                         /*}}}*/
  10 // Include Files                                                        /*{{{*/
  11 #include <config.h>
  12
  13 #include <apt-pkg/configuration.h>
  14 #include <apt-pkg/error.h>
  15 #include <apt-pkg/fileutl.h>
  16 #include <apt-pkg/strutl.h>
  17
  18 #include <ctype.h>
  19 #include <signal.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <sys/stat.h>
  23 #include <sys/time.h>
  24 #include <time.h>
  25 #include <unistd.h>
  26 #include <iostream>
  27 #include <limits>
  28 #include <map>
  29 #include <string>
  30 #include <vector>
  31
  32 #include "server.h"
  33
  34 #include <apti18n.h>
  35                                                                         /*}}}*/
  36 using namespace std;
  37
  38 string ServerMethod::FailFile;
  39 int ServerMethod::FailFd = -1;
  40 time_t ServerMethod::FailTime = 0;
  41
  42 // ServerState::RunHeaders - Get the headers before the data            /*{{{*/
  43 // ---------------------------------------------------------------------
  44 /* Returns 0 if things are OK, 1 if an IO error occurred and 2 if a header
  45    parse error occurred */
  46 ServerState::RunHeadersResult ServerState::RunHeaders(FileFd * const File,
  47                                                       const std::string &Uri)
  48 {
  49    State = Header;
  50
  51    Owner->Status(_("Waiting for headers"));
  52
  53    Major = 0;
  54    Minor = 0;
  55    Result = 0;
  56    TotalFileSize = 0;
  57    JunkSize = 0;
  58    StartPos = 0;
  59    Encoding = Closes;
  60    HaveContent = false;
  61    time(&Date);
  62
  63    do
  64    {
  65       string Data;
  66       if (ReadHeaderLines(Data) == false)
  67          continue;
  68
  69       if (Owner->Debug == true)
  70          clog << "Answer for: " << Uri << endl << Data;
  71
  72       for (string::const_iterator I = Data.begin(); I < Data.end(); ++I)
  73       {
  74          string::const_iterator J = I;
  75          for (; J != Data.end() && *J != '\n' && *J != '\r'; ++J);
  76          if (HeaderLine(string(I,J)) == false)
  77             return RUN_HEADERS_PARSE_ERROR;
  78          I = J;
  79       }
  80
  81       // 100 Continue is a Nop...
  82       if (Result == 100)
  83          continue;
  84
  85       // Tidy up the connection persistence state.
  86       if (Encoding == Closes && HaveContent == true)
  87          Persistent = false;
  88
  89       return RUN_HEADERS_OK;
  90    }
  91    while (LoadNextResponse(false, File) == true);
  92
  93    return RUN_HEADERS_IO_ERROR;
  94 }
  95                                                                         /*}}}*/
  96 // ServerState::HeaderLine - Process a header line                      /*{{{*/
  97 // ---------------------------------------------------------------------
  98 /* */
  99 bool ServerState::HeaderLine(string Line)
 100 {
 101    if (Line.empty() == true)
 102       return true;
 103
 104    string::size_type Pos = Line.find(' ');
 105    if (Pos == string::npos || Pos+1 > Line.length())
 106    {
 107       // Blah, some servers use "connection:closes", evil.
 108       Pos = Line.find(':');
 109       if (Pos == string::npos || Pos + 2 > Line.length())
 110          return _error->Error(_("Bad header line"));
 111       Pos++;
 112    }
 113
 114    // Parse off any trailing spaces between the : and the next word.
 115    string::size_type Pos2 = Pos;
 116    while (Pos2 < Line.length() && isspace_ascii(Line[Pos2]) != 0)
 117       Pos2++;
 118
 119    string Tag = string(Line,0,Pos);
 120    string Val = string(Line,Pos2);
 121
 122    if (stringcasecmp(Tag.c_str(),Tag.c_str()+4,"HTTP") == 0)
 123    {
 124       // Evil servers return no version
 125       if (Line[4] == '/')
 126       {
 127          int const elements = sscanf(Line.c_str(),"HTTP/%3u.%3u %3u%359[^\n]",&Major,&Minor,&Result,Code);
 128          if (elements == 3)
 129          {
 130             Code[0] = '\0';
 131             if (Owner != NULL && Owner->Debug == true)
 132                clog << "HTTP server doesn't give Reason-Phrase for " << std::to_string(Result) << std::endl;
 133          }
 134          else if (elements != 4)
 135             return _error->Error(_("The HTTP server sent an invalid reply header"));
 136       }
 137       else
 138       {
 139          Major = 0;
 140          Minor = 9;
 141          if (sscanf(Line.c_str(),"HTTP %3u%359[^\n]",&Result,Code) != 2)
 142             return _error->Error(_("The HTTP server sent an invalid reply header"));
 143       }
 144
 145       /* Check the HTTP response header to get the default persistence
 146          state. */
 147       if (Major < 1)
 148          Persistent = false;
 149       else
 150       {
 151          if (Major == 1 && Minor == 0)
 152          {
 153             Persistent = false;
 154          }
 155          else
 156          {
 157             Persistent = true;
 158             if (PipelineAllowed)
 159                Pipeline = true;
 160          }
 161       }
 162
 163       return true;
 164    }
 165
 166    if (stringcasecmp(Tag,"Content-Length:") == 0)
 167    {
 168       if (Encoding == Closes)
 169          Encoding = Stream;
 170       HaveContent = true;
 171
 172       unsigned long long * DownloadSizePtr = &DownloadSize;
 173       if (Result == 416)
 174          DownloadSizePtr = &JunkSize;
 175
 176       *DownloadSizePtr = strtoull(Val.c_str(), NULL, 10);
 177       if (*DownloadSizePtr >= std::numeric_limits<unsigned long long>::max())
 178          return _error->Errno("HeaderLine", _("The HTTP server sent an invalid Content-Length header"));
 179       else if (*DownloadSizePtr == 0)
 180          HaveContent = false;
 181
 182       // On partial content (206) the Content-Length less than the real
 183       // size, so do not set it here but leave that to the Content-Range
 184       // header instead
 185       if(Result != 206 && TotalFileSize == 0)
 186          TotalFileSize = DownloadSize;
 187
 188       return true;
 189    }
 190
 191    if (stringcasecmp(Tag,"Content-Type:") == 0)
 192    {
 193       HaveContent = true;
 194       return true;
 195    }
 196
 197    if (stringcasecmp(Tag,"Content-Range:") == 0)
 198    {
 199       HaveContent = true;
 200
 201       // §14.16 says 'byte-range-resp-spec' should be a '*' in case of 416
 202       if (Result == 416 && sscanf(Val.c_str(), "bytes */%llu",&TotalFileSize) == 1)
 203          ; // we got the expected filesize which is all we wanted
 204       else if (sscanf(Val.c_str(),"bytes %llu-%*u/%llu",&StartPos,&TotalFileSize) != 2)
 205          return _error->Error(_("The HTTP server sent an invalid Content-Range header"));
 206       if ((unsigned long long)StartPos > TotalFileSize)
 207          return _error->Error(_("This HTTP server has broken range support"));
 208
 209       // figure out what we will download
 210       DownloadSize = TotalFileSize - StartPos;
 211       return true;
 212    }
 213
 214    if (stringcasecmp(Tag,"Transfer-Encoding:") == 0)
 215    {
 216       HaveContent = true;
 217       if (stringcasecmp(Val,"chunked") == 0)
 218          Encoding = Chunked;
 219       return true;
 220    }
 221
 222    if (stringcasecmp(Tag,"Connection:") == 0)
 223    {
 224       if (stringcasecmp(Val,"close") == 0)
 225          Persistent = false;
 226       if (stringcasecmp(Val,"keep-alive") == 0)
 227          Persistent = true;
 228       return true;
 229    }
 230
 231    if (stringcasecmp(Tag,"Last-Modified:") == 0)
 232    {
 233       if (RFC1123StrToTime(Val.c_str(), Date) == false)
 234          return _error->Error(_("Unknown date format"));
 235       return true;
 236    }
 237
 238    if (stringcasecmp(Tag,"Location:") == 0)
 239    {
 240       Location = Val;
 241       return true;
 242    }
 243
 244    return true;
 245 }
 246                                                                         /*}}}*/
 247 // ServerState::ServerState - Constructor                               /*{{{*/
 248 ServerState::ServerState(URI Srv, ServerMethod *Owner) :
 249    DownloadSize(0), ServerName(Srv), TimeOut(120), Owner(Owner)
 250 {
 251    Reset();
 252 }
 253                                                                         /*}}}*/
 254 bool ServerState::AddPartialFileToHashes(FileFd &File)                  /*{{{*/
 255 {
 256    File.Truncate(StartPos);
 257    return GetHashes()->AddFD(File, StartPos);
 258 }
 259                                                                         /*}}}*/
 260
 261 // ServerMethod::DealWithHeaders - Handle the retrieved header data     /*{{{*/
 262 // ---------------------------------------------------------------------
 263 /* We look at the header data we got back from the server and decide what
 264    to do. Returns DealWithHeadersResult (see http.h for details).
 265  */
 266 ServerMethod::DealWithHeadersResult
 267 ServerMethod::DealWithHeaders(FetchResult &Res)
 268 {
 269    // Not Modified
 270    if (Server->Result == 304)
 271    {
 272       RemoveFile("server", Queue->DestFile);
 273       Res.IMSHit = true;
 274       Res.LastModified = Queue->LastModified;
 275       return IMS_HIT;
 276    }
 277
 278    /* Redirect
 279     *
 280     * Note that it is only OK for us to treat all redirection the same
 281     * because we *always* use GET, not other HTTP methods.  There are
 282     * three redirection codes for which it is not appropriate that we
 283     * redirect.  Pass on those codes so the error handling kicks in.
 284     */
 285    if (AllowRedirect
 286        && (Server->Result > 300 && Server->Result < 400)
 287        && (Server->Result != 300       // Multiple Choices
 288            && Server->Result != 304    // Not Modified
 289            && Server->Result != 306))  // (Not part of HTTP/1.1, reserved)
 290    {
 291       if (Server->Location.empty() == true);
 292       else if (Server->Location[0] == '/' && Queue->Uri.empty() == false)
 293       {
 294          URI Uri = Queue->Uri;
 295          if (Uri.Host.empty() == false)
 296             NextURI = URI::SiteOnly(Uri);
 297          else
 298             NextURI.clear();
 299          NextURI.append(DeQuoteString(Server->Location));
 300          return TRY_AGAIN_OR_REDIRECT;
 301       }
 302       else
 303       {
 304          NextURI = DeQuoteString(Server->Location);
 305          URI tmpURI = NextURI;
 306          URI Uri = Queue->Uri;
 307          // same protocol redirects are okay
 308          if (tmpURI.Access == Uri.Access)
 309             return TRY_AGAIN_OR_REDIRECT;
 310          // as well as http to https
 311          else if (Uri.Access == "http" && tmpURI.Access == "https")
 312             return TRY_AGAIN_OR_REDIRECT;
 313       }
 314       /* else pass through for error message */
 315    }
 316    // retry after an invalid range response without partial data
 317    else if (Server->Result == 416)
 318    {
 319       struct stat SBuf;
 320       if (stat(Queue->DestFile.c_str(),&SBuf) >= 0 && SBuf.st_size > 0)
 321       {
 322          bool partialHit = false;
 323          if (Queue->ExpectedHashes.usable() == true)
 324          {
 325             Hashes resultHashes(Queue->ExpectedHashes);
 326             FileFd file(Queue->DestFile, FileFd::ReadOnly);
 327             Server->TotalFileSize = file.FileSize();
 328             Server->Date = file.ModificationTime();
 329             resultHashes.AddFD(file);
 330             HashStringList const hashList = resultHashes.GetHashStringList();
 331             partialHit = (Queue->ExpectedHashes == hashList);
 332          }
 333          else if ((unsigned long long)SBuf.st_size == Server->TotalFileSize)
 334             partialHit = true;
 335          if (partialHit == true)
 336          {
 337             // the file is completely downloaded, but was not moved
 338             if (Server->HaveContent == true)
 339             {
 340                // Send to error page to dev/null
 341                FileFd DevNull("/dev/null",FileFd::WriteExists);
 342                Server->RunData(&DevNull);
 343             }
 344             Server->HaveContent = false;
 345             Server->StartPos = Server->TotalFileSize;
 346             Server->Result = 200;
 347          }
 348          else if (RemoveFile("server", Queue->DestFile))
 349          {
 350             NextURI = Queue->Uri;
 351             return TRY_AGAIN_OR_REDIRECT;
 352          }
 353       }
 354    }
 355
 356    /* We have a reply we don't handle. This should indicate a perm server
 357       failure */
 358    if (Server->Result < 200 || Server->Result >= 300)
 359    {
 360       std::string err;
 361       strprintf(err, "HttpError%u", Server->Result);
 362       SetFailReason(err);
 363       _error->Error("%u %s", Server->Result, Server->Code);
 364       if (Server->HaveContent == true)
 365          return ERROR_WITH_CONTENT_PAGE;
 366       return ERROR_UNRECOVERABLE;
 367    }
 368
 369    // This is some sort of 2xx 'data follows' reply
 370    Res.LastModified = Server->Date;
 371    Res.Size = Server->TotalFileSize;
 372
 373    // Open the file
 374    delete File;
 375    File = new FileFd(Queue->DestFile,FileFd::WriteAny);
 376    if (_error->PendingError() == true)
 377       return ERROR_NOT_FROM_SERVER;
 378
 379    FailFile = Queue->DestFile;
 380    FailFile.c_str();   // Make sure we don't do a malloc in the signal handler
 381    FailFd = File->Fd();
 382    FailTime = Server->Date;
 383
 384    if (Server->InitHashes(Queue->ExpectedHashes) == false || Server->AddPartialFileToHashes(*File) == false)
 385    {
 386       _error->Errno("read",_("Problem hashing file"));
 387       return ERROR_NOT_FROM_SERVER;
 388    }
 389    if (Server->StartPos > 0)
 390       Res.ResumePoint = Server->StartPos;
 391
 392    SetNonBlock(File->Fd(),true);
 393    return FILE_IS_OPEN;
 394 }
 395                                                                         /*}}}*/
 396 // ServerMethod::SigTerm - Handle a fatal signal                        /*{{{*/
 397 // ---------------------------------------------------------------------
 398 /* This closes and timestamps the open file. This is necessary to get
 399    resume behavoir on user abort */
 400 void ServerMethod::SigTerm(int)
 401 {
 402    if (FailFd == -1)
 403       _exit(100);
 404
 405    struct timeval times[2];
 406    times[0].tv_sec = FailTime;
 407    times[1].tv_sec = FailTime;
 408    times[0].tv_usec = times[1].tv_usec = 0;
 409    utimes(FailFile.c_str(), times);
 410    close(FailFd);
 411
 412    _exit(100);
 413 }
 414                                                                         /*}}}*/
 415 // ServerMethod::Fetch - Fetch an item                                  /*{{{*/
 416 // ---------------------------------------------------------------------
 417 /* This adds an item to the pipeline. We keep the pipeline at a fixed
 418    depth. */
 419 bool ServerMethod::Fetch(FetchItem *)
 420 {
 421    if (Server == nullptr || QueueBack == nullptr)
 422       return true;
 423
 424    // If pipelining is disabled, we only queue 1 request
 425    auto const AllowedDepth = Server->Pipeline ? PipelineDepth : 0;
 426    // how deep is our pipeline currently?
 427    decltype(PipelineDepth) CurrentDepth = 0;
 428    for (FetchItem const *I = Queue; I != QueueBack; I = I->Next)
 429       ++CurrentDepth;
 430    if (CurrentDepth > AllowedDepth)
 431       return true;
 432
 433    do {
 434       // Make sure we stick with the same server
 435       if (Server->Comp(QueueBack->Uri) == false)
 436          break;
 437
 438       bool const UsableHashes = QueueBack->ExpectedHashes.usable();
 439       // if we have no hashes, do at most one such request
 440       // as we can't fixup pipeling misbehaviors otherwise
 441       if (CurrentDepth != 0 && UsableHashes == false)
 442          break;
 443
 444       if (UsableHashes && FileExists(QueueBack->DestFile))
 445       {
 446          FileFd partial(QueueBack->DestFile, FileFd::ReadOnly);
 447          Hashes wehave(QueueBack->ExpectedHashes);
 448          if (QueueBack->ExpectedHashes.FileSize() == partial.FileSize())
 449          {
 450             if (wehave.AddFD(partial) &&
 451                   wehave.GetHashStringList() == QueueBack->ExpectedHashes)
 452             {
 453                FetchResult Res;
 454                Res.Filename = QueueBack->DestFile;
 455                Res.ResumePoint = QueueBack->ExpectedHashes.FileSize();
 456                URIStart(Res);
 457                // move item to the start of the queue as URIDone will
 458                // always dequeued the first item in the queue
 459                if (Queue != QueueBack)
 460                {
 461                   FetchItem *Prev = Queue;
 462                   for (; Prev->Next != QueueBack; Prev = Prev->Next)
 463                      /* look for the previous queue item */;
 464                   Prev->Next = QueueBack->Next;
 465                   QueueBack->Next = Queue;
 466                   Queue = QueueBack;
 467                   QueueBack = Prev->Next;
 468                }
 469                Res.TakeHashes(wehave);
 470                URIDone(Res);
 471                continue;
 472             }
 473             else
 474                RemoveFile("Fetch-Partial", QueueBack->DestFile);
 475          }
 476       }
 477       auto const Tmp = QueueBack;
 478       QueueBack = QueueBack->Next;
 479       SendReq(Tmp);
 480       ++CurrentDepth;
 481    } while (CurrentDepth <= AllowedDepth && QueueBack != nullptr);
 482
 483    return true;
 484 }
 485                                                                         /*}}}*/
 486 // ServerMethod::Loop - Main loop                                       /*{{{*/
 487 int ServerMethod::Loop()
 488 {
 489    typedef vector<string> StringVector;
 490    typedef vector<string>::iterator StringVectorIterator;
 491    map<string, StringVector> Redirected;
 492
 493    signal(SIGTERM,SigTerm);
 494    signal(SIGINT,SigTerm);
 495
 496    Server = 0;
 497
 498    int FailCounter = 0;
 499    while (1)
 500    {
 501       // We have no commands, wait for some to arrive
 502       if (Queue == 0)
 503       {
 504          if (WaitFd(STDIN_FILENO) == false)
 505             return 0;
 506       }
 507
 508       /* Run messages, we can accept 0 (no message) if we didn't
 509          do a WaitFd above.. Otherwise the FD is closed. */
 510       int Result = Run(true);
 511       if (Result != -1 && (Result != 0 || Queue == 0))
 512       {
 513          if(FailReason.empty() == false ||
 514             _config->FindB("Acquire::http::DependOnSTDIN", true) == true)
 515             return 100;
 516          else
 517             return 0;
 518       }
 519
 520       if (Queue == 0)
 521          continue;
 522
 523       // Connect to the server
 524       if (Server == 0 || Server->Comp(Queue->Uri) == false)
 525          Server = CreateServerState(Queue->Uri);
 526
 527       /* If the server has explicitly said this is the last connection
 528          then we pre-emptively shut down the pipeline and tear down
 529          the connection. This will speed up HTTP/1.0 servers a tad
 530          since we don't have to wait for the close sequence to
 531          complete */
 532       if (Server->Persistent == false)
 533          Server->Close();
 534
 535       // Reset the pipeline
 536       if (Server->IsOpen() == false)
 537          QueueBack = Queue;
 538
 539       // Connnect to the host
 540       if (Server->Open() == false)
 541       {
 542          Fail(true);
 543          Server = nullptr;
 544          continue;
 545       }
 546
 547       // Fill the pipeline.
 548       Fetch(0);
 549
 550       // Fetch the next URL header data from the server.
 551       switch (Server->RunHeaders(File, Queue->Uri))
 552       {
 553          case ServerState::RUN_HEADERS_OK:
 554          break;
 555
 556          // The header data is bad
 557          case ServerState::RUN_HEADERS_PARSE_ERROR:
 558          {
 559             _error->Error(_("Bad header data"));
 560             Fail(true);
 561             Server->Close();
 562             RotateDNS();
 563             continue;
 564          }
 565
 566          // The server closed a connection during the header get..
 567          default:
 568          case ServerState::RUN_HEADERS_IO_ERROR:
 569          {
 570             FailCounter++;
 571             _error->Discard();
 572             Server->Close();
 573             Server->Pipeline = false;
 574             Server->PipelineAllowed = false;
 575
 576             if (FailCounter >= 2)
 577             {
 578                Fail(_("Connection failed"),true);
 579                FailCounter = 0;
 580             }
 581
 582             RotateDNS();
 583             continue;
 584          }
 585       };
 586
 587       // Decide what to do.
 588       FetchResult Res;
 589       Res.Filename = Queue->DestFile;
 590       switch (DealWithHeaders(Res))
 591       {
 592          // Ok, the file is Open
 593          case FILE_IS_OPEN:
 594          {
 595             URIStart(Res);
 596
 597             // Run the data
 598             bool Result = true;
 599
 600             // ensure we don't fetch too much
 601             // we could do "Server->MaximumSize = Queue->MaximumSize" here
 602             // but that would break the clever pipeline messup detection
 603             // so instead we use the size of the biggest item in the queue
 604             Server->MaximumSize = FindMaximumObjectSizeInQueue();
 605
 606             if (Server->HaveContent)
 607                Result = Server->RunData(File);
 608
 609             /* If the server is sending back sizeless responses then fill in
 610                the size now */
 611             if (Res.Size == 0)
 612                Res.Size = File->Size();
 613
 614             // Close the file, destroy the FD object and timestamp it
 615             FailFd = -1;
 616             delete File;
 617             File = 0;
 618
 619             // Timestamp
 620             struct timeval times[2];
 621             times[0].tv_sec = times[1].tv_sec = Server->Date;
 622             times[0].tv_usec = times[1].tv_usec = 0;
 623             utimes(Queue->DestFile.c_str(), times);
 624
 625             // Send status to APT
 626             if (Result == true)
 627             {
 628                Hashes * const resultHashes = Server->GetHashes();
 629                HashStringList const hashList = resultHashes->GetHashStringList();
 630                if (PipelineDepth != 0 && Queue->ExpectedHashes.usable() == true && Queue->ExpectedHashes != hashList)
 631                {
 632                   // we did not get the expected hash… mhhh:
 633                   // could it be that server/proxy messed up pipelining?
 634                   FetchItem * BeforeI = Queue;
 635                   for (FetchItem *I = Queue->Next; I != 0 && I != QueueBack; I = I->Next)
 636                   {
 637                      if (I->ExpectedHashes.usable() == true && I->ExpectedHashes == hashList)
 638                      {
 639                         // yes, he did! Disable pipelining and rewrite queue
 640                         if (Server->Pipeline == true)
 641                         {
 642                            Warning(_("Automatically disabled %s due to incorrect response from server/proxy. (man 5 apt.conf)"), "Acquire::http::Pipeline-Depth");
 643                            Server->Pipeline = false;
 644                            Server->PipelineAllowed = false;
 645                            // we keep the PipelineDepth value so that the rest of the queue can be fixed up as well
 646                         }
 647                         Rename(Res.Filename, I->DestFile);
 648                         Res.Filename = I->DestFile;
 649                         BeforeI->Next = I->Next;
 650                         I->Next = Queue;
 651                         Queue = I;
 652                         break;
 653                      }
 654                      BeforeI = I;
 655                   }
 656                }
 657                Res.TakeHashes(*resultHashes);
 658                URIDone(Res);
 659             }
 660             else
 661             {
 662                if (Server->IsOpen() == false)
 663                {
 664                   FailCounter++;
 665                   _error->Discard();
 666                   Server->Close();
 667
 668                   if (FailCounter >= 2)
 669                   {
 670                      Fail(_("Connection failed"),true);
 671                      FailCounter = 0;
 672                   }
 673
 674                   QueueBack = Queue;
 675                }
 676                else
 677                {
 678                   Server->Close();
 679                   Fail(true);
 680                }
 681             }
 682             break;
 683          }
 684
 685          // IMS hit
 686          case IMS_HIT:
 687          {
 688             URIDone(Res);
 689             break;
 690          }
 691
 692          // Hard server error, not found or something
 693          case ERROR_UNRECOVERABLE:
 694          {
 695             Fail();
 696             break;
 697          }
 698
 699          // Hard internal error, kill the connection and fail
 700          case ERROR_NOT_FROM_SERVER:
 701          {
 702             delete File;
 703             File = 0;
 704
 705             Fail();
 706             RotateDNS();
 707             Server->Close();
 708             break;
 709          }
 710
 711          // We need to flush the data, the header is like a 404 w/ error text
 712          case ERROR_WITH_CONTENT_PAGE:
 713          {
 714             Fail();
 715
 716             // Send to content to dev/null
 717             File = new FileFd("/dev/null",FileFd::WriteExists);
 718             Server->RunData(File);
 719             delete File;
 720             File = 0;
 721             break;
 722          }
 723
 724          // Try again with a new URL
 725          case TRY_AGAIN_OR_REDIRECT:
 726          {
 727             // Clear rest of response if there is content
 728             if (Server->HaveContent)
 729             {
 730                File = new FileFd("/dev/null",FileFd::WriteExists);
 731                Server->RunData(File);
 732                delete File;
 733                File = 0;
 734             }
 735
 736             /* Detect redirect loops.  No more redirects are allowed
 737                after the same URI is seen twice in a queue item. */
 738             StringVector &R = Redirected[Queue->DestFile];
 739             bool StopRedirects = false;
 740             if (R.empty() == true)
 741                R.push_back(Queue->Uri);
 742             else if (R[0] == "STOP" || R.size() > 10)
 743                StopRedirects = true;
 744             else
 745             {
 746                for (StringVectorIterator I = R.begin(); I != R.end(); ++I)
 747                   if (Queue->Uri == *I)
 748                   {
 749                      R[0] = "STOP";
 750                      break;
 751                   }
 752
 753                R.push_back(Queue->Uri);
 754             }
 755
 756             if (StopRedirects == false)
 757                Redirect(NextURI);
 758             else
 759                Fail();
 760
 761             break;
 762          }
 763
 764          default:
 765          Fail(_("Internal error"));
 766          break;
 767       }
 768
 769       FailCounter = 0;
 770    }
 771
 772    return 0;
 773 }
 774                                                                         /*}}}*/
 775 unsigned long long ServerMethod::FindMaximumObjectSizeInQueue() const   /*{{{*/
 776 {
 777    unsigned long long MaxSizeInQueue = 0;
 778    for (FetchItem *I = Queue; I != 0 && I != QueueBack; I = I->Next)
 779       MaxSizeInQueue = std::max(MaxSizeInQueue, I->MaximumSize);
 780    return MaxSizeInQueue;
 781 }
 782                                                                         /*}}}*/
 783 ServerMethod::ServerMethod(char const * const Binary, char const * const Ver,unsigned long const Flags) :/*{{{*/
 784    aptMethod(Binary, Ver, Flags), Server(nullptr), File(NULL), PipelineDepth(10),
 785    AllowRedirect(false), Debug(false)
 786 {
 787 }
 788                                                                         /*}}}*/