methods/http.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: http.cc,v 1.59 2004/05/08 19:42:35 mdz Exp $
   4 /* ######################################################################
   5
   6    HTTP Acquire Method - This is the HTTP acquire method for APT.
   7
   8    It uses HTTP/1.1 and many of the fancy options there-in, such as
   9    pipelining, range, if-range and so on.
  10
  11    It is based on a doubly buffered select loop. A groupe of requests are
  12    fed into a single output buffer that is constantly fed out the
  13    socket. This provides ideal pipelining as in many cases all of the
  14    requests will fit into a single packet. The input socket is buffered
  15    the same way and fed into the fd for the file (may be a pipe in future).
  16
  17    This double buffering provides fairly substantial transfer rates,
  18    compared to wget the http method is about 4% faster. Most importantly,
  19    when HTTP is compared with FTP as a protocol the speed difference is
  20    huge. In tests over the internet from two sites to llug (via ATM) this
  21    program got 230k/s sustained http transfer rates. FTP on the other
  22    hand topped out at 170k/s. That combined with the time to setup the
  23    FTP connection makes HTTP a vastly superior protocol.
  24
  25    ##################################################################### */
  26                                                                         /*}}}*/
  27 // Include Files                                                        /*{{{*/
  28 #include <config.h>
  29
  30 #include <apt-pkg/fileutl.h>
  31 #include <apt-pkg/acquire-method.h>
  32 #include <apt-pkg/configuration.h>
  33 #include <apt-pkg/error.h>
  34 #include <apt-pkg/hashes.h>
  35 #include <apt-pkg/netrc.h>
  36
  37 #include <sys/stat.h>
  38 #include <sys/time.h>
  39 #include <unistd.h>
  40 #include <signal.h>
  41 #include <stdio.h>
  42 #include <errno.h>
  43 #include <string.h>
  44 #include <climits>
  45 #include <iostream>
  46 #include <map>
  47
  48 // Internet stuff
  49 #include <netdb.h>
  50
  51 #include "config.h"
  52 #include "connect.h"
  53 #include "rfc2553emu.h"
  54 #include "http.h"
  55
  56 #include <apti18n.h>
  57                                                                         /*}}}*/
  58 using namespace std;
  59
  60 unsigned long long CircleBuf::BwReadLimit=0;
  61 unsigned long long CircleBuf::BwTickReadData=0;
  62 struct timeval CircleBuf::BwReadTick={0,0};
  63 const unsigned int CircleBuf::BW_HZ=10;
  64
  65 // CircleBuf::CircleBuf - Circular input buffer                         /*{{{*/
  66 // ---------------------------------------------------------------------
  67 /* */
  68 CircleBuf::CircleBuf(unsigned long long Size) : Size(Size), Hash(0)
  69 {
  70    Buf = new unsigned char[Size];
  71    Reset();
  72
  73    CircleBuf::BwReadLimit = _config->FindI("Acquire::http::Dl-Limit",0)*1024;
  74 }
  75                                                                         /*}}}*/
  76 // CircleBuf::Reset - Reset to the default state                        /*{{{*/
  77 // ---------------------------------------------------------------------
  78 /* */
  79 void CircleBuf::Reset()
  80 {
  81    InP = 0;
  82    OutP = 0;
  83    StrPos = 0;
  84    MaxGet = (unsigned long long)-1;
  85    OutQueue = string();
  86    if (Hash != 0)
  87    {
  88       delete Hash;
  89       Hash = new Hashes;
  90    }
  91 }
  92                                                                         /*}}}*/
  93 // CircleBuf::Read - Read from a FD into the circular buffer            /*{{{*/
  94 // ---------------------------------------------------------------------
  95 /* This fills up the buffer with as much data as is in the FD, assuming it
  96    is non-blocking.. */
  97 bool CircleBuf::Read(int Fd)
  98 {
  99    while (1)
 100    {
 101       // Woops, buffer is full
 102       if (InP - OutP == Size)
 103          return true;
 104
 105       // what's left to read in this tick
 106       unsigned long long const BwReadMax = CircleBuf::BwReadLimit/BW_HZ;
 107
 108       if(CircleBuf::BwReadLimit) {
 109          struct timeval now;
 110          gettimeofday(&now,0);
 111
 112          unsigned long long d = (now.tv_sec-CircleBuf::BwReadTick.tv_sec)*1000000 +
 113             now.tv_usec-CircleBuf::BwReadTick.tv_usec;
 114          if(d > 1000000/BW_HZ) {
 115             CircleBuf::BwReadTick = now;
 116             CircleBuf::BwTickReadData = 0;
 117          }
 118
 119          if(CircleBuf::BwTickReadData >= BwReadMax) {
 120             usleep(1000000/BW_HZ);
 121             return true;
 122          }
 123       }
 124
 125       // Write the buffer segment
 126       ssize_t Res;
 127       if(CircleBuf::BwReadLimit) {
 128          Res = read(Fd,Buf + (InP%Size),
 129                     BwReadMax > LeftRead() ? LeftRead() : BwReadMax);
 130       } else
 131          Res = read(Fd,Buf + (InP%Size),LeftRead());
 132
 133       if(Res > 0 && BwReadLimit > 0)
 134          CircleBuf::BwTickReadData += Res;
 135
 136       if (Res == 0)
 137          return false;
 138       if (Res < 0)
 139       {
 140          if (errno == EAGAIN)
 141             return true;
 142          return false;
 143       }
 144
 145       if (InP == 0)
 146          gettimeofday(&Start,0);
 147       InP += Res;
 148    }
 149 }
 150                                                                         /*}}}*/
 151 // CircleBuf::Read - Put the string into the buffer                     /*{{{*/
 152 // ---------------------------------------------------------------------
 153 /* This will hold the string in and fill the buffer with it as it empties */
 154 bool CircleBuf::Read(string Data)
 155 {
 156    OutQueue += Data;
 157    FillOut();
 158    return true;
 159 }
 160                                                                         /*}}}*/
 161 // CircleBuf::FillOut - Fill the buffer from the output queue           /*{{{*/
 162 // ---------------------------------------------------------------------
 163 /* */
 164 void CircleBuf::FillOut()
 165 {
 166    if (OutQueue.empty() == true)
 167       return;
 168    while (1)
 169    {
 170       // Woops, buffer is full
 171       if (InP - OutP == Size)
 172          return;
 173
 174       // Write the buffer segment
 175       unsigned long long Sz = LeftRead();
 176       if (OutQueue.length() - StrPos < Sz)
 177          Sz = OutQueue.length() - StrPos;
 178       memcpy(Buf + (InP%Size),OutQueue.c_str() + StrPos,Sz);
 179
 180       // Advance
 181       StrPos += Sz;
 182       InP += Sz;
 183       if (OutQueue.length() == StrPos)
 184       {
 185          StrPos = 0;
 186          OutQueue = "";
 187          return;
 188       }
 189    }
 190 }
 191                                                                         /*}}}*/
 192 // CircleBuf::Write - Write from the buffer into a FD                   /*{{{*/
 193 // ---------------------------------------------------------------------
 194 /* This empties the buffer into the FD. */
 195 bool CircleBuf::Write(int Fd)
 196 {
 197    while (1)
 198    {
 199       FillOut();
 200
 201       // Woops, buffer is empty
 202       if (OutP == InP)
 203          return true;
 204
 205       if (OutP == MaxGet)
 206          return true;
 207
 208       // Write the buffer segment
 209       ssize_t Res;
 210       Res = write(Fd,Buf + (OutP%Size),LeftWrite());
 211
 212       if (Res == 0)
 213          return false;
 214       if (Res < 0)
 215       {
 216          if (errno == EAGAIN)
 217             return true;
 218
 219          return false;
 220       }
 221
 222       if (Hash != 0)
 223          Hash->Add(Buf + (OutP%Size),Res);
 224
 225       OutP += Res;
 226    }
 227 }
 228                                                                         /*}}}*/
 229 // CircleBuf::WriteTillEl - Write from the buffer to a string           /*{{{*/
 230 // ---------------------------------------------------------------------
 231 /* This copies till the first empty line */
 232 bool CircleBuf::WriteTillEl(string &Data,bool Single)
 233 {
 234    // We cheat and assume it is unneeded to have more than one buffer load
 235    for (unsigned long long I = OutP; I < InP; I++)
 236    {
 237       if (Buf[I%Size] != '\n')
 238          continue;
 239       ++I;
 240
 241       if (Single == false)
 242       {
 243          if (I < InP  && Buf[I%Size] == '\r')
 244             ++I;
 245          if (I >= InP || Buf[I%Size] != '\n')
 246             continue;
 247          ++I;
 248       }
 249
 250       Data = "";
 251       while (OutP < I)
 252       {
 253          unsigned long long Sz = LeftWrite();
 254          if (Sz == 0)
 255             return false;
 256          if (I - OutP < Sz)
 257             Sz = I - OutP;
 258          Data += string((char *)(Buf + (OutP%Size)),Sz);
 259          OutP += Sz;
 260       }
 261       return true;
 262    }
 263    return false;
 264 }
 265                                                                         /*}}}*/
 266 // CircleBuf::Stats - Print out stats information                       /*{{{*/
 267 // ---------------------------------------------------------------------
 268 /* */
 269 void CircleBuf::Stats()
 270 {
 271    if (InP == 0)
 272       return;
 273
 274    struct timeval Stop;
 275    gettimeofday(&Stop,0);
 276 /*   float Diff = Stop.tv_sec - Start.tv_sec +
 277              (float)(Stop.tv_usec - Start.tv_usec)/1000000;
 278    clog << "Got " << InP << " in " << Diff << " at " << InP/Diff << endl;*/
 279 }
 280                                                                         /*}}}*/
 281 CircleBuf::~CircleBuf()
 282 {
 283    delete [] Buf;
 284    delete Hash;
 285 }
 286
 287 // HttpServerState::HttpServerState - Constructor                       /*{{{*/
 288 HttpServerState::HttpServerState(URI Srv,HttpMethod *Owner) : ServerState(Srv, Owner), In(64*1024), Out(4*1024)
 289 {
 290    TimeOut = _config->FindI("Acquire::http::Timeout",TimeOut);
 291    Reset();
 292 }
 293                                                                         /*}}}*/
 294 // HttpServerState::Open - Open a connection to the server              /*{{{*/
 295 // ---------------------------------------------------------------------
 296 /* This opens a connection to the server. */
 297 bool HttpServerState::Open()
 298 {
 299    // Use the already open connection if possible.
 300    if (ServerFd != -1)
 301       return true;
 302
 303    Close();
 304    In.Reset();
 305    Out.Reset();
 306    Persistent = true;
 307
 308    // Determine the proxy setting
 309    string SpecificProxy = _config->Find("Acquire::http::Proxy::" + ServerName.Host);
 310    if (!SpecificProxy.empty())
 311    {
 312            if (SpecificProxy == "DIRECT")
 313                    Proxy = "";
 314            else
 315                    Proxy = SpecificProxy;
 316    }
 317    else
 318    {
 319            string DefProxy = _config->Find("Acquire::http::Proxy");
 320            if (!DefProxy.empty())
 321            {
 322                    Proxy = DefProxy;
 323            }
 324            else
 325            {
 326                    char* result = getenv("http_proxy");
 327                    Proxy = result ? result : "";
 328            }
 329    }
 330
 331    // Parse no_proxy, a , separated list of domains
 332    if (getenv("no_proxy") != 0)
 333    {
 334       if (CheckDomainList(ServerName.Host,getenv("no_proxy")) == true)
 335          Proxy = "";
 336    }
 337
 338    // Determine what host and port to use based on the proxy settings
 339    int Port = 0;
 340    string Host;
 341    if (Proxy.empty() == true || Proxy.Host.empty() == true)
 342    {
 343       if (ServerName.Port != 0)
 344          Port = ServerName.Port;
 345       Host = ServerName.Host;
 346    }
 347    else
 348    {
 349       if (Proxy.Port != 0)
 350          Port = Proxy.Port;
 351       Host = Proxy.Host;
 352    }
 353
 354    // Connect to the remote server
 355    if (Connect(Host,Port,"http",80,ServerFd,TimeOut,Owner) == false)
 356       return false;
 357
 358    return true;
 359 }
 360                                                                         /*}}}*/
 361 // HttpServerState::Close - Close a connection to the server            /*{{{*/
 362 // ---------------------------------------------------------------------
 363 /* */
 364 bool HttpServerState::Close()
 365 {
 366    close(ServerFd);
 367    ServerFd = -1;
 368    return true;
 369 }
 370                                                                         /*}}}*/
 371 // HttpServerState::RunData - Transfer the data from the socket         /*{{{*/
 372 bool HttpServerState::RunData(FileFd * const File)
 373 {
 374    State = Data;
 375
 376    // Chunked transfer encoding is fun..
 377    if (Encoding == Chunked)
 378    {
 379       while (1)
 380       {
 381          // Grab the block size
 382          bool Last = true;
 383          string Data;
 384          In.Limit(-1);
 385          do
 386          {
 387             if (In.WriteTillEl(Data,true) == true)
 388                break;
 389          }
 390          while ((Last = Go(false, File)) == true);
 391
 392          if (Last == false)
 393             return false;
 394
 395          // See if we are done
 396          unsigned long long Len = strtoull(Data.c_str(),0,16);
 397          if (Len == 0)
 398          {
 399             In.Limit(-1);
 400
 401             // We have to remove the entity trailer
 402             Last = true;
 403             do
 404             {
 405                if (In.WriteTillEl(Data,true) == true && Data.length() <= 2)
 406                   break;
 407             }
 408             while ((Last = Go(false, File)) == true);
 409             if (Last == false)
 410                return false;
 411             return !_error->PendingError();
 412          }
 413
 414          // Transfer the block
 415          In.Limit(Len);
 416          while (Go(true, File) == true)
 417             if (In.IsLimit() == true)
 418                break;
 419
 420          // Error
 421          if (In.IsLimit() == false)
 422             return false;
 423
 424          // The server sends an extra new line before the next block specifier..
 425          In.Limit(-1);
 426          Last = true;
 427          do
 428          {
 429             if (In.WriteTillEl(Data,true) == true)
 430                break;
 431          }
 432          while ((Last = Go(false, File)) == true);
 433          if (Last == false)
 434             return false;
 435       }
 436    }
 437    else
 438    {
 439       /* Closes encoding is used when the server did not specify a size, the
 440          loss of the connection means we are done */
 441       if (Encoding == Closes)
 442          In.Limit(-1);
 443       else
 444          In.Limit(Size - StartPos);
 445
 446       // Just transfer the whole block.
 447       do
 448       {
 449          if (In.IsLimit() == false)
 450             continue;
 451
 452          In.Limit(-1);
 453          return !_error->PendingError();
 454       }
 455       while (Go(true, File) == true);
 456    }
 457
 458    return Owner->Flush() && !_error->PendingError();
 459 }
 460                                                                         /*}}}*/
 461 bool HttpServerState::ReadHeaderLines(std::string &Data)                /*{{{*/
 462 {
 463    return In.WriteTillEl(Data);
 464 }
 465                                                                         /*}}}*/
 466 bool HttpServerState::LoadNextResponse(bool const ToFile, FileFd * const File)/*{{{*/
 467 {
 468    return Go(ToFile, File);
 469 }
 470                                                                         /*}}}*/
 471 bool HttpServerState::WriteResponse(const std::string &Data)            /*{{{*/
 472 {
 473    return Out.Read(Data);
 474 }
 475                                                                         /*}}}*/
 476 bool HttpServerState::IsOpen()                                          /*{{{*/
 477 {
 478    return (ServerFd != -1);
 479 }
 480                                                                         /*}}}*/
 481 bool HttpServerState::InitHashes(FileFd &File)                          /*{{{*/
 482 {
 483    delete In.Hash;
 484    In.Hash = new Hashes;
 485
 486    // Set the expected size and read file for the hashes
 487    File.Truncate(StartPos);
 488    return In.Hash->AddFD(File, StartPos);
 489 }
 490                                                                         /*}}}*/
 491 Hashes * HttpServerState::GetHashes()                                   /*{{{*/
 492 {
 493    return In.Hash;
 494 }
 495                                                                         /*}}}*/
 496 // HttpServerState::Die - The server has closed the connection.         /*{{{*/
 497 bool HttpServerState::Die(FileFd &File)
 498 {
 499    unsigned int LErrno = errno;
 500
 501    // Dump the buffer to the file
 502    if (State == ServerState::Data)
 503    {
 504       // on GNU/kFreeBSD, apt dies on /dev/null because non-blocking
 505       // can't be set
 506       if (File.Name() != "/dev/null")
 507          SetNonBlock(File.Fd(),false);
 508       while (In.WriteSpace() == true)
 509       {
 510          if (In.Write(File.Fd()) == false)
 511             return _error->Errno("write",_("Error writing to the file"));
 512
 513          // Done
 514          if (In.IsLimit() == true)
 515             return true;
 516       }
 517    }
 518
 519    // See if this is because the server finished the data stream
 520    if (In.IsLimit() == false && State != HttpServerState::Header &&
 521        Encoding != HttpServerState::Closes)
 522    {
 523       Close();
 524       if (LErrno == 0)
 525          return _error->Error(_("Error reading from server. Remote end closed connection"));
 526       errno = LErrno;
 527       return _error->Errno("read",_("Error reading from server"));
 528    }
 529    else
 530    {
 531       In.Limit(-1);
 532
 533       // Nothing left in the buffer
 534       if (In.WriteSpace() == false)
 535          return false;
 536
 537       // We may have got multiple responses back in one packet..
 538       Close();
 539       return true;
 540    }
 541
 542    return false;
 543 }
 544                                                                         /*}}}*/
 545 // HttpServerState::Flush - Dump the buffer into the file               /*{{{*/
 546 // ---------------------------------------------------------------------
 547 /* This takes the current input buffer from the Server FD and writes it
 548    into the file */
 549 bool HttpServerState::Flush(FileFd * const File)
 550 {
 551    if (File != NULL)
 552    {
 553       // on GNU/kFreeBSD, apt dies on /dev/null because non-blocking
 554       // can't be set
 555       if (File->Name() != "/dev/null")
 556          SetNonBlock(File->Fd(),false);
 557       if (In.WriteSpace() == false)
 558          return true;
 559
 560       while (In.WriteSpace() == true)
 561       {
 562          if (In.Write(File->Fd()) == false)
 563             return _error->Errno("write",_("Error writing to file"));
 564          if (In.IsLimit() == true)
 565             return true;
 566       }
 567
 568       if (In.IsLimit() == true || Encoding == ServerState::Closes)
 569          return true;
 570    }
 571    return false;
 572 }
 573                                                                         /*}}}*/
 574 // HttpServerState::Go - Run a single loop                              /*{{{*/
 575 // ---------------------------------------------------------------------
 576 /* This runs the select loop over the server FDs, Output file FDs and
 577    stdin. */
 578 bool HttpServerState::Go(bool ToFile, FileFd * const File)
 579 {
 580    // Server has closed the connection
 581    if (ServerFd == -1 && (In.WriteSpace() == false ||
 582                                ToFile == false))
 583       return false;
 584
 585    fd_set rfds,wfds;
 586    FD_ZERO(&rfds);
 587    FD_ZERO(&wfds);
 588
 589    /* Add the server. We only send more requests if the connection will
 590       be persisting */
 591    if (Out.WriteSpace() == true && ServerFd != -1
 592        && Persistent == true)
 593       FD_SET(ServerFd,&wfds);
 594    if (In.ReadSpace() == true && ServerFd != -1)
 595       FD_SET(ServerFd,&rfds);
 596
 597    // Add the file
 598    int FileFD = -1;
 599    if (File != NULL)
 600       FileFD = File->Fd();
 601
 602    if (In.WriteSpace() == true && ToFile == true && FileFD != -1)
 603       FD_SET(FileFD,&wfds);
 604
 605    // Add stdin
 606    if (_config->FindB("Acquire::http::DependOnSTDIN", true) == true)
 607       FD_SET(STDIN_FILENO,&rfds);
 608
 609    // Figure out the max fd
 610    int MaxFd = FileFD;
 611    if (MaxFd < ServerFd)
 612       MaxFd = ServerFd;
 613
 614    // Select
 615    struct timeval tv;
 616    tv.tv_sec = TimeOut;
 617    tv.tv_usec = 0;
 618    int Res = 0;
 619    if ((Res = select(MaxFd+1,&rfds,&wfds,0,&tv)) < 0)
 620    {
 621       if (errno == EINTR)
 622          return true;
 623       return _error->Errno("select",_("Select failed"));
 624    }
 625
 626    if (Res == 0)
 627    {
 628       _error->Error(_("Connection timed out"));
 629       return Die(*File);
 630    }
 631
 632    // Handle server IO
 633    if (ServerFd != -1 && FD_ISSET(ServerFd,&rfds))
 634    {
 635       errno = 0;
 636       if (In.Read(ServerFd) == false)
 637          return Die(*File);
 638    }
 639
 640    if (ServerFd != -1 && FD_ISSET(ServerFd,&wfds))
 641    {
 642       errno = 0;
 643       if (Out.Write(ServerFd) == false)
 644          return Die(*File);
 645    }
 646
 647    // Send data to the file
 648    if (FileFD != -1 && FD_ISSET(FileFD,&wfds))
 649    {
 650       if (In.Write(FileFD) == false)
 651          return _error->Errno("write",_("Error writing to output file"));
 652    }
 653
 654    // Handle commands from APT
 655    if (FD_ISSET(STDIN_FILENO,&rfds))
 656    {
 657       if (Owner->Run(true) != -1)
 658          exit(100);
 659    }
 660
 661    return true;
 662 }
 663                                                                         /*}}}*/
 664
 665 // HttpMethod::SendReq - Send the HTTP request                          /*{{{*/
 666 // ---------------------------------------------------------------------
 667 /* This places the http request in the outbound buffer */
 668 void HttpMethod::SendReq(FetchItem *Itm)
 669 {
 670    URI Uri = Itm->Uri;
 671
 672    // The HTTP server expects a hostname with a trailing :port
 673    char Buf[1000];
 674    string ProperHost;
 675
 676    if (Uri.Host.find(':') != string::npos)
 677       ProperHost = '[' + Uri.Host + ']';
 678    else
 679       ProperHost = Uri.Host;
 680    if (Uri.Port != 0)
 681    {
 682       sprintf(Buf,":%u",Uri.Port);
 683       ProperHost += Buf;
 684    }
 685
 686    // Just in case.
 687    if (Itm->Uri.length() >= sizeof(Buf))
 688        abort();
 689
 690    /* RFC 2616 §5.1.2 requires absolute URIs for requests to proxies,
 691       but while its a must for all servers to accept absolute URIs,
 692       it is assumed clients will sent an absolute path for non-proxies */
 693    std::string requesturi;
 694    if (Server->Proxy.empty() == true || Server->Proxy.Host.empty())
 695       requesturi = Uri.Path;
 696    else
 697       requesturi = Itm->Uri;
 698
 699    // The "+" is encoded as a workaround for a amazon S3 bug
 700    // see LP bugs #1003633 and #1086997.
 701    requesturi = QuoteString(requesturi, "+~ ");
 702
 703    /* Build the request. No keep-alive is included as it is the default
 704       in 1.1, can cause problems with proxies, and we are an HTTP/1.1
 705       client anyway.
 706       C.f. https://tools.ietf.org/wg/httpbis/trac/ticket/158 */
 707    sprintf(Buf,"GET %s HTTP/1.1\r\nHost: %s\r\n",
 708            requesturi.c_str(),ProperHost.c_str());
 709
 710    // generate a cache control header (if needed)
 711    if (_config->FindB("Acquire::http::No-Cache",false) == true)
 712    {
 713       strcat(Buf,"Cache-Control: no-cache\r\nPragma: no-cache\r\n");
 714    }
 715    else
 716    {
 717       if (Itm->IndexFile == true)
 718       {
 719          sprintf(Buf+strlen(Buf),"Cache-Control: max-age=%u\r\n",
 720                  _config->FindI("Acquire::http::Max-Age",0));
 721       }
 722       else
 723       {
 724          if (_config->FindB("Acquire::http::No-Store",false) == true)
 725             strcat(Buf,"Cache-Control: no-store\r\n");
 726       }
 727    }
 728
 729    // If we ask for uncompressed files servers might respond with content-
 730    // negotiation which lets us end up with compressed files we do not support,
 731    // see 657029, 657560 and co, so if we have no extension on the request
 732    // ask for text only. As a sidenote: If there is nothing to negotate servers
 733    // seem to be nice and ignore it.
 734    if (_config->FindB("Acquire::http::SendAccept", true) == true)
 735    {
 736       size_t const filepos = Itm->Uri.find_last_of('/');
 737       string const file = Itm->Uri.substr(filepos + 1);
 738       if (flExtension(file) == file)
 739          strcat(Buf,"Accept: text/*\r\n");
 740    }
 741
 742    string Req = Buf;
 743
 744    // Check for a partial file
 745    struct stat SBuf;
 746    if (stat(Itm->DestFile.c_str(),&SBuf) >= 0 && SBuf.st_size > 0)
 747    {
 748       // In this case we send an if-range query with a range header
 749       sprintf(Buf,"Range: bytes=%lli-\r\nIf-Range: %s\r\n",(long long)SBuf.st_size,
 750               TimeRFC1123(SBuf.st_mtime).c_str());
 751       Req += Buf;
 752    }
 753    else
 754    {
 755       if (Itm->LastModified != 0)
 756       {
 757          sprintf(Buf,"If-Modified-Since: %s\r\n",TimeRFC1123(Itm->LastModified).c_str());
 758          Req += Buf;
 759       }
 760    }
 761
 762    if (Server->Proxy.User.empty() == false || Server->Proxy.Password.empty() == false)
 763       Req += string("Proxy-Authorization: Basic ") +
 764           Base64Encode(Server->Proxy.User + ":" + Server->Proxy.Password) + "\r\n";
 765
 766    maybe_add_auth (Uri, _config->FindFile("Dir::Etc::netrc"));
 767    if (Uri.User.empty() == false || Uri.Password.empty() == false)
 768    {
 769       Req += string("Authorization: Basic ") +
 770           Base64Encode(Uri.User + ":" + Uri.Password) + "\r\n";
 771    }
 772    Req += "User-Agent: " + _config->Find("Acquire::http::User-Agent",
 773                 "Debian APT-HTTP/1.3 (" PACKAGE_VERSION ")") + "\r\n\r\n";
 774
 775    if (Debug == true)
 776       cerr << Req << endl;
 777
 778    Server->WriteResponse(Req);
 779 }
 780                                                                         /*}}}*/
 781 // HttpMethod::Configuration - Handle a configuration message           /*{{{*/
 782 // ---------------------------------------------------------------------
 783 /* We stash the desired pipeline depth */
 784 bool HttpMethod::Configuration(string Message)
 785 {
 786    if (ServerMethod::Configuration(Message) == false)
 787       return false;
 788
 789    AllowRedirect = _config->FindB("Acquire::http::AllowRedirect",true);
 790    PipelineDepth = _config->FindI("Acquire::http::Pipeline-Depth",
 791                                   PipelineDepth);
 792    Debug = _config->FindB("Debug::Acquire::http",false);
 793
 794    // Get the proxy to use
 795    AutoDetectProxy();
 796
 797    return true;
 798 }
 799                                                                         /*}}}*/
 800 // HttpMethod::AutoDetectProxy - auto detect proxy                      /*{{{*/
 801 // ---------------------------------------------------------------------
 802 /* */
 803 bool HttpMethod::AutoDetectProxy()
 804 {
 805    // option is "Acquire::http::Proxy-Auto-Detect" but we allow the old
 806    // name without the dash ("-")
 807    AutoDetectProxyCmd = _config->Find("Acquire::http::Proxy-Auto-Detect",
 808                                       _config->Find("Acquire::http::ProxyAutoDetect"));
 809
 810    if (AutoDetectProxyCmd.empty())
 811       return true;
 812
 813    if (Debug)
 814       clog << "Using auto proxy detect command: " << AutoDetectProxyCmd << endl;
 815
 816    int Pipes[2] = {-1,-1};
 817    if (pipe(Pipes) != 0)
 818       return _error->Errno("pipe", "Failed to create Pipe");
 819
 820    pid_t Process = ExecFork();
 821    if (Process == 0)
 822    {
 823       close(Pipes[0]);
 824       dup2(Pipes[1],STDOUT_FILENO);
 825       SetCloseExec(STDOUT_FILENO,false);
 826
 827       const char *Args[2];
 828       Args[0] = AutoDetectProxyCmd.c_str();
 829       Args[1] = 0;
 830       execv(Args[0],(char **)Args);
 831       cerr << "Failed to exec method " << Args[0] << endl;
 832       _exit(100);
 833    }
 834    char buf[512];
 835    int InFd = Pipes[0];
 836    close(Pipes[1]);
 837    int res = read(InFd, buf, sizeof(buf)-1);
 838    ExecWait(Process, "ProxyAutoDetect", true);
 839
 840    if (res < 0)
 841       return _error->Errno("read", "Failed to read");
 842    if (res == 0)
 843       return _error->Warning("ProxyAutoDetect returned no data");
 844
 845    // add trailing \0
 846    buf[res] = 0;
 847
 848    if (Debug)
 849       clog << "auto detect command returned: '" << buf << "'" << endl;
 850
 851    if (strstr(buf, "http://") == buf)
 852       _config->Set("Acquire::http::proxy", _strstrip(buf));
 853
 854    return true;
 855 }
 856                                                                         /*}}}*/
 857 ServerState * HttpMethod::CreateServerState(URI uri)                    /*{{{*/
 858 {
 859    return new HttpServerState(uri, this);
 860 }
 861                                                                         /*}}}*/
 862 void HttpMethod::RotateDNS()                                            /*{{{*/
 863 {
 864    ::RotateDNS();
 865 }
 866                                                                         /*}}}*/