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