methods/server.cc

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