methods/http.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: http.cc,v 1.46 2000/05/28 04:33:59 jgg Exp $
   4 /* ######################################################################
   5
   6    HTTP Aquire Method - This is the HTTP aquire 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 <apt-pkg/fileutl.h>
  29 #include <apt-pkg/acquire-method.h>
  30 #include <apt-pkg/error.h>
  31 #include <apt-pkg/md5.h>
  32
  33 #include <sys/stat.h>
  34 #include <sys/time.h>
  35 #include <utime.h>
  36 #include <unistd.h>
  37 #include <signal.h>
  38 #include <stdio.h>
  39 #include <errno.h>
  40
  41 // Internet stuff
  42 #include <netdb.h>
  43
  44 #include "connect.h"
  45 #include "rfc2553emu.h"
  46 #include "http.h"
  47
  48                                                                         /*}}}*/
  49
  50 string HttpMethod::FailFile;
  51 int HttpMethod::FailFd = -1;
  52 time_t HttpMethod::FailTime = 0;
  53 unsigned long PipelineDepth = 10;
  54 unsigned long TimeOut = 120;
  55 bool Debug = false;
  56
  57 // CircleBuf::CircleBuf - Circular input buffer                         /*{{{*/
  58 // ---------------------------------------------------------------------
  59 /* */
  60 CircleBuf::CircleBuf(unsigned long Size) : Size(Size), MD5(0)
  61 {
  62    Buf = new unsigned char[Size];
  63    Reset();
  64 }
  65                                                                         /*}}}*/
  66 // CircleBuf::Reset - Reset to the default state                        /*{{{*/
  67 // ---------------------------------------------------------------------
  68 /* */
  69 void CircleBuf::Reset()
  70 {
  71    InP = 0;
  72    OutP = 0;
  73    StrPos = 0;
  74    MaxGet = (unsigned int)-1;
  75    OutQueue = string();
  76    if (MD5 != 0)
  77    {
  78       delete MD5;
  79       MD5 = new MD5Summation;
  80    }
  81 };
  82                                                                         /*}}}*/
  83 // CircleBuf::Read - Read from a FD into the circular buffer            /*{{{*/
  84 // ---------------------------------------------------------------------
  85 /* This fills up the buffer with as much data as is in the FD, assuming it
  86    is non-blocking.. */
  87 bool CircleBuf::Read(int Fd)
  88 {
  89    while (1)
  90    {
  91       // Woops, buffer is full
  92       if (InP - OutP == Size)
  93          return true;
  94
  95       // Write the buffer segment
  96       int Res;
  97       Res = read(Fd,Buf + (InP%Size),LeftRead());
  98
  99       if (Res == 0)
 100          return false;
 101       if (Res < 0)
 102       {
 103          if (errno == EAGAIN)
 104             return true;
 105          return false;
 106       }
 107
 108       if (InP == 0)
 109          gettimeofday(&Start,0);
 110       InP += Res;
 111    }
 112 }
 113                                                                         /*}}}*/
 114 // CircleBuf::Read - Put the string into the buffer                     /*{{{*/
 115 // ---------------------------------------------------------------------
 116 /* This will hold the string in and fill the buffer with it as it empties */
 117 bool CircleBuf::Read(string Data)
 118 {
 119    OutQueue += Data;
 120    FillOut();
 121    return true;
 122 }
 123                                                                         /*}}}*/
 124 // CircleBuf::FillOut - Fill the buffer from the output queue           /*{{{*/
 125 // ---------------------------------------------------------------------
 126 /* */
 127 void CircleBuf::FillOut()
 128 {
 129    if (OutQueue.empty() == true)
 130       return;
 131    while (1)
 132    {
 133       // Woops, buffer is full
 134       if (InP - OutP == Size)
 135          return;
 136
 137       // Write the buffer segment
 138       unsigned long Sz = LeftRead();
 139       if (OutQueue.length() - StrPos < Sz)
 140          Sz = OutQueue.length() - StrPos;
 141       memcpy(Buf + (InP%Size),OutQueue.begin() + StrPos,Sz);
 142
 143       // Advance
 144       StrPos += Sz;
 145       InP += Sz;
 146       if (OutQueue.length() == StrPos)
 147       {
 148          StrPos = 0;
 149          OutQueue = "";
 150          return;
 151       }
 152    }
 153 }
 154                                                                         /*}}}*/
 155 // CircleBuf::Write - Write from the buffer into a FD                   /*{{{*/
 156 // ---------------------------------------------------------------------
 157 /* This empties the buffer into the FD. */
 158 bool CircleBuf::Write(int Fd)
 159 {
 160    while (1)
 161    {
 162       FillOut();
 163
 164       // Woops, buffer is empty
 165       if (OutP == InP)
 166          return true;
 167
 168       if (OutP == MaxGet)
 169          return true;
 170
 171       // Write the buffer segment
 172       int Res;
 173       Res = write(Fd,Buf + (OutP%Size),LeftWrite());
 174
 175       if (Res == 0)
 176          return false;
 177       if (Res < 0)
 178       {
 179          if (errno == EAGAIN)
 180             return true;
 181
 182          return false;
 183       }
 184
 185       if (MD5 != 0)
 186          MD5->Add(Buf + (OutP%Size),Res);
 187
 188       OutP += Res;
 189    }
 190 }
 191                                                                         /*}}}*/
 192 // CircleBuf::WriteTillEl - Write from the buffer to a string           /*{{{*/
 193 // ---------------------------------------------------------------------
 194 /* This copies till the first empty line */
 195 bool CircleBuf::WriteTillEl(string &Data,bool Single)
 196 {
 197    // We cheat and assume it is unneeded to have more than one buffer load
 198    for (unsigned long I = OutP; I < InP; I++)
 199    {
 200       if (Buf[I%Size] != '\n')
 201          continue;
 202       for (I++; I < InP && Buf[I%Size] == '\r'; I++);
 203
 204       if (Single == false)
 205       {
 206          if (Buf[I%Size] != '\n')
 207             continue;
 208          for (I++; I < InP && Buf[I%Size] == '\r'; I++);
 209       }
 210
 211       if (I > InP)
 212          I = InP;
 213
 214       Data = "";
 215       while (OutP < I)
 216       {
 217          unsigned long Sz = LeftWrite();
 218          if (Sz == 0)
 219             return false;
 220          if (I - OutP < LeftWrite())
 221             Sz = I - OutP;
 222          Data += string((char *)(Buf + (OutP%Size)),Sz);
 223          OutP += Sz;
 224       }
 225       return true;
 226    }
 227    return false;
 228 }
 229                                                                         /*}}}*/
 230 // CircleBuf::Stats - Print out stats information                       /*{{{*/
 231 // ---------------------------------------------------------------------
 232 /* */
 233 void CircleBuf::Stats()
 234 {
 235    if (InP == 0)
 236       return;
 237
 238    struct timeval Stop;
 239    gettimeofday(&Stop,0);
 240 /*   float Diff = Stop.tv_sec - Start.tv_sec +
 241              (float)(Stop.tv_usec - Start.tv_usec)/1000000;
 242    clog << "Got " << InP << " in " << Diff << " at " << InP/Diff << endl;*/
 243 }
 244                                                                         /*}}}*/
 245
 246 // ServerState::ServerState - Constructor                               /*{{{*/
 247 // ---------------------------------------------------------------------
 248 /* */
 249 ServerState::ServerState(URI Srv,HttpMethod *Owner) : Owner(Owner),
 250                         In(64*1024), Out(4*1024),
 251                         ServerName(Srv)
 252 {
 253    Reset();
 254 }
 255                                                                         /*}}}*/
 256 // ServerState::Open - Open a connection to the server                  /*{{{*/
 257 // ---------------------------------------------------------------------
 258 /* This opens a connection to the server. */
 259 bool ServerState::Open()
 260 {
 261    // Use the already open connection if possible.
 262    if (ServerFd != -1)
 263       return true;
 264
 265    Close();
 266    In.Reset();
 267    Out.Reset();
 268    Persistent = true;
 269
 270    // Determine the proxy setting
 271    if (getenv("http_proxy") == 0)
 272    {
 273       string DefProxy = _config->Find("Acquire::http::Proxy");
 274       string SpecificProxy = _config->Find("Acquire::http::Proxy::" + ServerName.Host);
 275       if (SpecificProxy.empty() == false)
 276       {
 277          if (SpecificProxy == "DIRECT")
 278             Proxy = "";
 279          else
 280             Proxy = SpecificProxy;
 281       }
 282       else
 283          Proxy = DefProxy;
 284    }
 285    else
 286       Proxy = getenv("http_proxy");
 287
 288    // Parse no_proxy, a , seperated list of hosts
 289    if (getenv("no_proxy") != 0)
 290    {
 291       const char *Start = getenv("no_proxy");
 292       for (const char *Cur = Start; true ; Cur++)
 293       {
 294          if (*Cur != ',' && *Cur != 0)
 295             continue;
 296          if (stringcasecmp(ServerName.Host.begin(),ServerName.Host.end(),
 297                            Start,Cur) == 0)
 298          {
 299             Proxy = "";
 300             break;
 301          }
 302
 303          Start = Cur + 1;
 304          if (*Cur == 0)
 305             break;
 306       }
 307    }
 308
 309    // Determine what host and port to use based on the proxy settings
 310    int Port = 0;
 311    string Host;
 312    if (Proxy.empty() == true || Proxy.Host.empty() == true)
 313    {
 314       if (ServerName.Port != 0)
 315          Port = ServerName.Port;
 316       Host = ServerName.Host;
 317    }
 318    else
 319    {
 320       if (Proxy.Port != 0)
 321          Port = Proxy.Port;
 322       Host = Proxy.Host;
 323    }
 324
 325    // Connect to the remote server
 326    if (Connect(Host,Port,"http",80,ServerFd,TimeOut,Owner) == false)
 327       return false;
 328
 329    return true;
 330 }
 331                                                                         /*}}}*/
 332 // ServerState::Close - Close a connection to the server                /*{{{*/
 333 // ---------------------------------------------------------------------
 334 /* */
 335 bool ServerState::Close()
 336 {
 337    close(ServerFd);
 338    ServerFd = -1;
 339    return true;
 340 }
 341                                                                         /*}}}*/
 342 // ServerState::RunHeaders - Get the headers before the data            /*{{{*/
 343 // ---------------------------------------------------------------------
 344 /* Returns 0 if things are OK, 1 if an IO error occursed and 2 if a header
 345    parse error occured */
 346 int ServerState::RunHeaders()
 347 {
 348    State = Header;
 349
 350    Owner->Status("Waiting for file");
 351
 352    Major = 0;
 353    Minor = 0;
 354    Result = 0;
 355    Size = 0;
 356    StartPos = 0;
 357    Encoding = Closes;
 358    HaveContent = false;
 359    time(&Date);
 360
 361    do
 362    {
 363       string Data;
 364       if (In.WriteTillEl(Data) == false)
 365          continue;
 366
 367       if (Debug == true)
 368          clog << Data;
 369
 370       for (string::const_iterator I = Data.begin(); I < Data.end(); I++)
 371       {
 372          string::const_iterator J = I;
 373          for (; J != Data.end() && *J != '\n' && *J != '\r';J++);
 374          if (HeaderLine(string(I,J-I)) == false)
 375             return 2;
 376          I = J;
 377       }
 378
 379       // Tidy up the connection persistance state.
 380       if (Encoding == Closes && HaveContent == true)
 381          Persistent = false;
 382
 383       return 0;
 384    }
 385    while (Owner->Go(false,this) == true);
 386
 387    return 1;
 388 }
 389                                                                         /*}}}*/
 390 // ServerState::RunData - Transfer the data from the socket             /*{{{*/
 391 // ---------------------------------------------------------------------
 392 /* */
 393 bool ServerState::RunData()
 394 {
 395    State = Data;
 396
 397    // Chunked transfer encoding is fun..
 398    if (Encoding == Chunked)
 399    {
 400       while (1)
 401       {
 402          // Grab the block size
 403          bool Last = true;
 404          string Data;
 405          In.Limit(-1);
 406          do
 407          {
 408             if (In.WriteTillEl(Data,true) == true)
 409                break;
 410          }
 411          while ((Last = Owner->Go(false,this)) == true);
 412
 413          if (Last == false)
 414             return false;
 415
 416          // See if we are done
 417          unsigned long Len = strtol(Data.c_str(),0,16);
 418          if (Len == 0)
 419          {
 420             In.Limit(-1);
 421
 422             // We have to remove the entity trailer
 423             Last = true;
 424             do
 425             {
 426                if (In.WriteTillEl(Data,true) == true && Data.length() <= 2)
 427                   break;
 428             }
 429             while ((Last = Owner->Go(false,this)) == true);
 430             if (Last == false)
 431                return false;
 432             return !_error->PendingError();
 433          }
 434
 435          // Transfer the block
 436          In.Limit(Len);
 437          while (Owner->Go(true,this) == true)
 438             if (In.IsLimit() == true)
 439                break;
 440
 441          // Error
 442          if (In.IsLimit() == false)
 443             return false;
 444
 445          // The server sends an extra new line before the next block specifier..
 446          In.Limit(-1);
 447          Last = true;
 448          do
 449          {
 450             if (In.WriteTillEl(Data,true) == true)
 451                break;
 452          }
 453          while ((Last = Owner->Go(false,this)) == true);
 454          if (Last == false)
 455             return false;
 456       }
 457    }
 458    else
 459    {
 460       /* Closes encoding is used when the server did not specify a size, the
 461          loss of the connection means we are done */
 462       if (Encoding == Closes)
 463          In.Limit(-1);
 464       else
 465          In.Limit(Size - StartPos);
 466
 467       // Just transfer the whole block.
 468       do
 469       {
 470          if (In.IsLimit() == false)
 471             continue;
 472
 473          In.Limit(-1);
 474          return !_error->PendingError();
 475       }
 476       while (Owner->Go(true,this) == true);
 477    }
 478
 479    return Owner->Flush(this) && !_error->PendingError();
 480 }
 481                                                                         /*}}}*/
 482 // ServerState::HeaderLine - Process a header line                      /*{{{*/
 483 // ---------------------------------------------------------------------
 484 /* */
 485 bool ServerState::HeaderLine(string Line)
 486 {
 487    if (Line.empty() == true)
 488       return true;
 489
 490    // The http server might be trying to do something evil.
 491    if (Line.length() >= MAXLEN)
 492       return _error->Error("Got a single header line over %u chars",MAXLEN);
 493
 494    string::size_type Pos = Line.find(' ');
 495    if (Pos == string::npos || Pos+1 > Line.length())
 496    {
 497       // Blah, some servers use "connection:closes", evil.
 498       Pos = Line.find(':');
 499       if (Pos == string::npos || Pos + 2 > Line.length())
 500          return _error->Error("Bad header line");
 501       Pos++;
 502    }
 503
 504    // Parse off any trailing spaces between the : and the next word.
 505    string::size_type Pos2 = Pos;
 506    while (Pos2 < Line.length() && isspace(Line[Pos2]) != 0)
 507       Pos2++;
 508
 509    string Tag = string(Line,0,Pos);
 510    string Val = string(Line,Pos2);
 511
 512    if (stringcasecmp(Tag.begin(),Tag.begin()+4,"HTTP") == 0)
 513    {
 514       // Evil servers return no version
 515       if (Line[4] == '/')
 516       {
 517          if (sscanf(Line.c_str(),"HTTP/%u.%u %u %[^\n]",&Major,&Minor,
 518                     &Result,Code) != 4)
 519             return _error->Error("The http server sent an invalid reply header");
 520       }
 521       else
 522       {
 523          Major = 0;
 524          Minor = 9;
 525          if (sscanf(Line.c_str(),"HTTP %u %[^\n]",&Result,Code) != 2)
 526             return _error->Error("The http server sent an invalid reply header");
 527       }
 528
 529       /* Check the HTTP response header to get the default persistance
 530          state. */
 531       if (Major < 1)
 532          Persistent = false;
 533       else
 534       {
 535          if (Major == 1 && Minor <= 0)
 536             Persistent = false;
 537          else
 538             Persistent = true;
 539       }
 540
 541       return true;
 542    }
 543
 544    if (stringcasecmp(Tag,"Content-Length:") == 0)
 545    {
 546       if (Encoding == Closes)
 547          Encoding = Stream;
 548       HaveContent = true;
 549
 550       // The length is already set from the Content-Range header
 551       if (StartPos != 0)
 552          return true;
 553
 554       if (sscanf(Val.c_str(),"%lu",&Size) != 1)
 555          return _error->Error("The http server sent an invalid Content-Length header");
 556       return true;
 557    }
 558
 559    if (stringcasecmp(Tag,"Content-Type:") == 0)
 560    {
 561       HaveContent = true;
 562       return true;
 563    }
 564
 565    if (stringcasecmp(Tag,"Content-Range:") == 0)
 566    {
 567       HaveContent = true;
 568
 569       if (sscanf(Val.c_str(),"bytes %lu-%*u/%lu",&StartPos,&Size) != 2)
 570          return _error->Error("The http server sent an invalid Content-Range header");
 571       if ((unsigned)StartPos > Size)
 572          return _error->Error("This http server has broken range support");
 573       return true;
 574    }
 575
 576    if (stringcasecmp(Tag,"Transfer-Encoding:") == 0)
 577    {
 578       HaveContent = true;
 579       if (stringcasecmp(Val,"chunked") == 0)
 580          Encoding = Chunked;
 581       return true;
 582    }
 583
 584    if (stringcasecmp(Tag,"Connection:") == 0)
 585    {
 586       if (stringcasecmp(Val,"close") == 0)
 587          Persistent = false;
 588       if (stringcasecmp(Val,"keep-alive") == 0)
 589          Persistent = true;
 590       return true;
 591    }
 592
 593    if (stringcasecmp(Tag,"Last-Modified:") == 0)
 594    {
 595       if (StrToTime(Val,Date) == false)
 596          return _error->Error("Unknown date format");
 597       return true;
 598    }
 599
 600    return true;
 601 }
 602                                                                         /*}}}*/
 603
 604 // HttpMethod::SendReq - Send the HTTP request                          /*{{{*/
 605 // ---------------------------------------------------------------------
 606 /* This places the http request in the outbound buffer */
 607 void HttpMethod::SendReq(FetchItem *Itm,CircleBuf &Out)
 608 {
 609    URI Uri = Itm->Uri;
 610
 611    // The HTTP server expects a hostname with a trailing :port
 612    char Buf[1000];
 613    string ProperHost = Uri.Host;
 614    if (Uri.Port != 0)
 615    {
 616       sprintf(Buf,":%u",Uri.Port);
 617       ProperHost += Buf;
 618    }
 619
 620    // Just in case.
 621    if (Itm->Uri.length() >= sizeof(Buf))
 622        abort();
 623
 624    /* Build the request. We include a keep-alive header only for non-proxy
 625       requests. This is to tweak old http/1.0 servers that do support keep-alive
 626       but not HTTP/1.1 automatic keep-alive. Doing this with a proxy server
 627       will glitch HTTP/1.0 proxies because they do not filter it out and
 628       pass it on, HTTP/1.1 says the connection should default to keep alive
 629       and we expect the proxy to do this */
 630    if (Proxy.empty() == true)
 631       sprintf(Buf,"GET %s HTTP/1.1\r\nHost: %s\r\nConnection: keep-alive\r\n",
 632               QuoteString(Uri.Path,"~").c_str(),ProperHost.c_str());
 633    else
 634    {
 635       /* Generate a cache control header if necessary. We place a max
 636          cache age on index files, optionally set a no-cache directive
 637          and a no-store directive for archives. */
 638       sprintf(Buf,"GET %s HTTP/1.1\r\nHost: %s\r\n",
 639               Itm->Uri.c_str(),ProperHost.c_str());
 640       if (_config->FindB("Acquire::http::No-Cache",false) == true)
 641          strcat(Buf,"Cache-Control: no-cache\r\nPragma: no-cache\r\n");
 642       else
 643       {
 644          if (Itm->IndexFile == true)
 645             sprintf(Buf+strlen(Buf),"Cache-Control: max-age=%u\r\n",
 646                     _config->FindI("Acquire::http::Max-Age",60*60*24));
 647          else
 648          {
 649             if (_config->FindB("Acquire::http::No-Store",false) == true)
 650                strcat(Buf,"Cache-Control: no-store\r\n");
 651          }
 652       }
 653    }
 654
 655    string Req = Buf;
 656
 657    // Check for a partial file
 658    struct stat SBuf;
 659    if (stat(Itm->DestFile.c_str(),&SBuf) >= 0 && SBuf.st_size > 0)
 660    {
 661       // In this case we send an if-range query with a range header
 662       sprintf(Buf,"Range: bytes=%li-\r\nIf-Range: %s\r\n",(long)SBuf.st_size - 1,
 663               TimeRFC1123(SBuf.st_mtime).c_str());
 664       Req += Buf;
 665    }
 666    else
 667    {
 668       if (Itm->LastModified != 0)
 669       {
 670          sprintf(Buf,"If-Modified-Since: %s\r\n",TimeRFC1123(Itm->LastModified).c_str());
 671          Req += Buf;
 672       }
 673    }
 674
 675    if (Proxy.User.empty() == false || Proxy.Password.empty() == false)
 676       Req += string("Proxy-Authorization: Basic ") +
 677           Base64Encode(Proxy.User + ":" + Proxy.Password) + "\r\n";
 678
 679    Req += "User-Agent: Debian APT-HTTP/1.2\r\n\r\n";
 680
 681    if (Debug == true)
 682       cerr << Req << endl;
 683
 684    Out.Read(Req);
 685 }
 686                                                                         /*}}}*/
 687 // HttpMethod::Go - Run a single loop                                   /*{{{*/
 688 // ---------------------------------------------------------------------
 689 /* This runs the select loop over the server FDs, Output file FDs and
 690    stdin. */
 691 bool HttpMethod::Go(bool ToFile,ServerState *Srv)
 692 {
 693    // Server has closed the connection
 694    if (Srv->ServerFd == -1 && (Srv->In.WriteSpace() == false ||
 695                                ToFile == false))
 696       return false;
 697
 698    fd_set rfds,wfds;
 699    FD_ZERO(&rfds);
 700    FD_ZERO(&wfds);
 701
 702    /* Add the server. We only send more requests if the connection will
 703       be persisting */
 704    if (Srv->Out.WriteSpace() == true && Srv->ServerFd != -1
 705        && Srv->Persistent == true)
 706       FD_SET(Srv->ServerFd,&wfds);
 707    if (Srv->In.ReadSpace() == true && Srv->ServerFd != -1)
 708       FD_SET(Srv->ServerFd,&rfds);
 709
 710    // Add the file
 711    int FileFD = -1;
 712    if (File != 0)
 713       FileFD = File->Fd();
 714
 715    if (Srv->In.WriteSpace() == true && ToFile == true && FileFD != -1)
 716       FD_SET(FileFD,&wfds);
 717
 718    // Add stdin
 719    FD_SET(STDIN_FILENO,&rfds);
 720
 721    // Figure out the max fd
 722    int MaxFd = FileFD;
 723    if (MaxFd < Srv->ServerFd)
 724       MaxFd = Srv->ServerFd;
 725
 726    // Select
 727    struct timeval tv;
 728    tv.tv_sec = TimeOut;
 729    tv.tv_usec = 0;
 730    int Res = 0;
 731    if ((Res = select(MaxFd+1,&rfds,&wfds,0,&tv)) < 0)
 732       return _error->Errno("select","Select failed");
 733
 734    if (Res == 0)
 735    {
 736       _error->Error("Connection timed out");
 737       return ServerDie(Srv);
 738    }
 739
 740    // Handle server IO
 741    if (Srv->ServerFd != -1 && FD_ISSET(Srv->ServerFd,&rfds))
 742    {
 743       errno = 0;
 744       if (Srv->In.Read(Srv->ServerFd) == false)
 745          return ServerDie(Srv);
 746    }
 747
 748    if (Srv->ServerFd != -1 && FD_ISSET(Srv->ServerFd,&wfds))
 749    {
 750       errno = 0;
 751       if (Srv->Out.Write(Srv->ServerFd) == false)
 752          return ServerDie(Srv);
 753    }
 754
 755    // Send data to the file
 756    if (FileFD != -1 && FD_ISSET(FileFD,&wfds))
 757    {
 758       if (Srv->In.Write(FileFD) == false)
 759          return _error->Errno("write","Error writing to output file");
 760    }
 761
 762    // Handle commands from APT
 763    if (FD_ISSET(STDIN_FILENO,&rfds))
 764    {
 765       if (Run(true) != -1)
 766          exit(100);
 767    }
 768
 769    return true;
 770 }
 771                                                                         /*}}}*/
 772 // HttpMethod::Flush - Dump the buffer into the file                    /*{{{*/
 773 // ---------------------------------------------------------------------
 774 /* This takes the current input buffer from the Server FD and writes it
 775    into the file */
 776 bool HttpMethod::Flush(ServerState *Srv)
 777 {
 778    if (File != 0)
 779    {
 780       SetNonBlock(File->Fd(),false);
 781       if (Srv->In.WriteSpace() == false)
 782          return true;
 783
 784       while (Srv->In.WriteSpace() == true)
 785       {
 786          if (Srv->In.Write(File->Fd()) == false)
 787             return _error->Errno("write","Error writing to file");
 788          if (Srv->In.IsLimit() == true)
 789             return true;
 790       }
 791
 792       if (Srv->In.IsLimit() == true || Srv->Encoding == ServerState::Closes)
 793          return true;
 794    }
 795    return false;
 796 }
 797                                                                         /*}}}*/
 798 // HttpMethod::ServerDie - The server has closed the connection.        /*{{{*/
 799 // ---------------------------------------------------------------------
 800 /* */
 801 bool HttpMethod::ServerDie(ServerState *Srv)
 802 {
 803    unsigned int LErrno = errno;
 804
 805    // Dump the buffer to the file
 806    if (Srv->State == ServerState::Data)
 807    {
 808       SetNonBlock(File->Fd(),false);
 809       while (Srv->In.WriteSpace() == true)
 810       {
 811          if (Srv->In.Write(File->Fd()) == false)
 812             return _error->Errno("write","Error writing to the file");
 813
 814          // Done
 815          if (Srv->In.IsLimit() == true)
 816             return true;
 817       }
 818    }
 819
 820    // See if this is because the server finished the data stream
 821    if (Srv->In.IsLimit() == false && Srv->State != ServerState::Header &&
 822        Srv->Encoding != ServerState::Closes)
 823    {
 824       Srv->Close();
 825       if (LErrno == 0)
 826          return _error->Error("Error reading from server Remote end closed connection");
 827       errno = LErrno;
 828       return _error->Errno("read","Error reading from server");
 829    }
 830    else
 831    {
 832       Srv->In.Limit(-1);
 833
 834       // Nothing left in the buffer
 835       if (Srv->In.WriteSpace() == false)
 836          return false;
 837
 838       // We may have got multiple responses back in one packet..
 839       Srv->Close();
 840       return true;
 841    }
 842
 843    return false;
 844 }
 845                                                                         /*}}}*/
 846 // HttpMethod::DealWithHeaders - Handle the retrieved header data       /*{{{*/
 847 // ---------------------------------------------------------------------
 848 /* We look at the header data we got back from the server and decide what
 849    to do. Returns
 850      0 - File is open,
 851      1 - IMS hit
 852      3 - Unrecoverable error
 853      4 - Error with error content page
 854      5 - Unrecoverable non-server error (close the connection) */
 855 int HttpMethod::DealWithHeaders(FetchResult &Res,ServerState *Srv)
 856 {
 857    // Not Modified
 858    if (Srv->Result == 304)
 859    {
 860       unlink(Queue->DestFile.c_str());
 861       Res.IMSHit = true;
 862       Res.LastModified = Queue->LastModified;
 863       return 1;
 864    }
 865
 866    /* We have a reply we dont handle. This should indicate a perm server
 867       failure */
 868    if (Srv->Result < 200 || Srv->Result >= 300)
 869    {
 870       _error->Error("%u %s",Srv->Result,Srv->Code);
 871       if (Srv->HaveContent == true)
 872          return 4;
 873       return 3;
 874    }
 875
 876    // This is some sort of 2xx 'data follows' reply
 877    Res.LastModified = Srv->Date;
 878    Res.Size = Srv->Size;
 879
 880    // Open the file
 881    delete File;
 882    File = new FileFd(Queue->DestFile,FileFd::WriteAny);
 883    if (_error->PendingError() == true)
 884       return 5;
 885
 886    FailFile = Queue->DestFile;
 887    FailFile.c_str();   // Make sure we dont do a malloc in the signal handler
 888    FailFd = File->Fd();
 889    FailTime = Srv->Date;
 890
 891    // Set the expected size
 892    if (Srv->StartPos >= 0)
 893    {
 894       Res.ResumePoint = Srv->StartPos;
 895       ftruncate(File->Fd(),Srv->StartPos);
 896    }
 897
 898    // Set the start point
 899    lseek(File->Fd(),0,SEEK_END);
 900
 901    delete Srv->In.MD5;
 902    Srv->In.MD5 = new MD5Summation;
 903
 904    // Fill the MD5 Hash if the file is non-empty (resume)
 905    if (Srv->StartPos > 0)
 906    {
 907       lseek(File->Fd(),0,SEEK_SET);
 908       if (Srv->In.MD5->AddFD(File->Fd(),Srv->StartPos) == false)
 909       {
 910          _error->Errno("read","Problem hashing file");
 911          return 5;
 912       }
 913       lseek(File->Fd(),0,SEEK_END);
 914    }
 915
 916    SetNonBlock(File->Fd(),true);
 917    return 0;
 918 }
 919                                                                         /*}}}*/
 920 // HttpMethod::SigTerm - Handle a fatal signal                          /*{{{*/
 921 // ---------------------------------------------------------------------
 922 /* This closes and timestamps the open file. This is neccessary to get
 923    resume behavoir on user abort */
 924 void HttpMethod::SigTerm(int)
 925 {
 926    if (FailFd == -1)
 927       _exit(100);
 928    close(FailFd);
 929
 930    // Timestamp
 931    struct utimbuf UBuf;
 932    UBuf.actime = FailTime;
 933    UBuf.modtime = FailTime;
 934    utime(FailFile.c_str(),&UBuf);
 935
 936    _exit(100);
 937 }
 938                                                                         /*}}}*/
 939 // HttpMethod::Fetch - Fetch an item                                    /*{{{*/
 940 // ---------------------------------------------------------------------
 941 /* This adds an item to the pipeline. We keep the pipeline at a fixed
 942    depth. */
 943 bool HttpMethod::Fetch(FetchItem *)
 944 {
 945    if (Server == 0)
 946       return true;
 947
 948    // Queue the requests
 949    int Depth = -1;
 950    bool Tail = false;
 951    for (FetchItem *I = Queue; I != 0 && Depth < (signed)PipelineDepth;
 952         I = I->Next, Depth++)
 953    {
 954       // If pipelining is disabled, we only queue 1 request
 955       if (Server->Pipeline == false && Depth >= 0)
 956          break;
 957
 958       // Make sure we stick with the same server
 959       if (Server->Comp(I->Uri) == false)
 960          break;
 961       if (QueueBack == I)
 962          Tail = true;
 963       if (Tail == true)
 964       {
 965          QueueBack = I->Next;
 966          SendReq(I,Server->Out);
 967          continue;
 968       }
 969    }
 970
 971    return true;
 972 };
 973                                                                         /*}}}*/
 974 // HttpMethod::Configuration - Handle a configuration message           /*{{{*/
 975 // ---------------------------------------------------------------------
 976 /* We stash the desired pipeline depth */
 977 bool HttpMethod::Configuration(string Message)
 978 {
 979    if (pkgAcqMethod::Configuration(Message) == false)
 980       return false;
 981
 982    TimeOut = _config->FindI("Acquire::http::Timeout",TimeOut);
 983    PipelineDepth = _config->FindI("Acquire::http::Pipeline-Depth",
 984                                   PipelineDepth);
 985    Debug = _config->FindB("Debug::Acquire::http",false);
 986
 987    return true;
 988 }
 989                                                                         /*}}}*/
 990 // HttpMethod::Loop - Main loop                                         /*{{{*/
 991 // ---------------------------------------------------------------------
 992 /* */
 993 int HttpMethod::Loop()
 994 {
 995    signal(SIGTERM,SigTerm);
 996    signal(SIGINT,SigTerm);
 997
 998    Server = 0;
 999
1000    int FailCounter = 0;
1001    while (1)
1002    {
1003       // We have no commands, wait for some to arrive
1004       if (Queue == 0)
1005       {
1006          if (WaitFd(STDIN_FILENO) == false)
1007             return 0;
1008       }
1009
1010       /* Run messages, we can accept 0 (no message) if we didn't
1011          do a WaitFd above.. Otherwise the FD is closed. */
1012       int Result = Run(true);
1013       if (Result != -1 && (Result != 0 || Queue == 0))
1014          return 100;
1015
1016       if (Queue == 0)
1017          continue;
1018
1019       // Connect to the server
1020       if (Server == 0 || Server->Comp(Queue->Uri) == false)
1021       {
1022          delete Server;
1023          Server = new ServerState(Queue->Uri,this);
1024       }
1025
1026       /* If the server has explicitly said this is the last connection
1027          then we pre-emptively shut down the pipeline and tear down
1028          the connection. This will speed up HTTP/1.0 servers a tad
1029          since we don't have to wait for the close sequence to
1030          complete */
1031       if (Server->Persistent == false)
1032          Server->Close();
1033
1034       // Reset the pipeline
1035       if (Server->ServerFd == -1)
1036          QueueBack = Queue;
1037
1038       // Connnect to the host
1039       if (Server->Open() == false)
1040       {
1041          Fail(true);
1042          delete Server;
1043          Server = 0;
1044          continue;
1045       }
1046
1047       // Fill the pipeline.
1048       Fetch(0);
1049
1050       // Fetch the next URL header data from the server.
1051       switch (Server->RunHeaders())
1052       {
1053          case 0:
1054          break;
1055
1056          // The header data is bad
1057          case 2:
1058          {
1059             _error->Error("Bad header Data");
1060             Fail(true);
1061             continue;
1062          }
1063
1064          // The server closed a connection during the header get..
1065          default:
1066          case 1:
1067          {
1068             FailCounter++;
1069             _error->Discard();
1070             Server->Close();
1071             Server->Pipeline = false;
1072
1073             if (FailCounter >= 2)
1074             {
1075                Fail("Connection failed",true);
1076                FailCounter = 0;
1077             }
1078
1079             continue;
1080          }
1081       };
1082
1083       // Decide what to do.
1084       FetchResult Res;
1085       Res.Filename = Queue->DestFile;
1086       switch (DealWithHeaders(Res,Server))
1087       {
1088          // Ok, the file is Open
1089          case 0:
1090          {
1091             URIStart(Res);
1092
1093             // Run the data
1094             bool Result =  Server->RunData();
1095
1096             // Close the file, destroy the FD object and timestamp it
1097             FailFd = -1;
1098             delete File;
1099             File = 0;
1100
1101             // Timestamp
1102             struct utimbuf UBuf;
1103             time(&UBuf.actime);
1104             UBuf.actime = Server->Date;
1105             UBuf.modtime = Server->Date;
1106             utime(Queue->DestFile.c_str(),&UBuf);
1107
1108             // Send status to APT
1109             if (Result == true)
1110             {
1111                Res.MD5Sum = Server->In.MD5->Result();
1112                URIDone(Res);
1113             }
1114             else
1115                Fail(true);
1116
1117             break;
1118          }
1119
1120          // IMS hit
1121          case 1:
1122          {
1123             URIDone(Res);
1124             break;
1125          }
1126
1127          // Hard server error, not found or something
1128          case 3:
1129          {
1130             Fail();
1131             break;
1132          }
1133
1134          // Hard internal error, kill the connection and fail
1135          case 5:
1136          {
1137             Fail();
1138             Server->Close();
1139             break;
1140          }
1141
1142          // We need to flush the data, the header is like a 404 w/ error text
1143          case 4:
1144          {
1145             Fail();
1146
1147             // Send to content to dev/null
1148             File = new FileFd("/dev/null",FileFd::WriteExists);
1149             Server->RunData();
1150             delete File;
1151             File = 0;
1152             break;
1153          }
1154
1155          default:
1156          Fail("Internal error");
1157          break;
1158       }
1159
1160       FailCounter = 0;
1161    }
1162
1163    return 0;
1164 }
1165                                                                         /*}}}*/
1166
1167 int main()
1168 {
1169    HttpMethod Mth;
1170
1171    return Mth.Loop();
1172 }