apt-pkg/acquire-worker.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: acquire-worker.cc,v 1.34 2001/05/22 04:42:54 jgg Exp $
   4 /* ######################################################################
   5
   6    Acquire Worker
   7
   8    The worker process can startup either as a Configuration prober
   9    or as a queue runner. As a configuration prober it only reads the
  10    configuration message and
  11
  12    ##################################################################### */
  13                                                                         /*}}}*/
  14 // Include Files                                                        /*{{{*/
  15 #include <config.h>
  16
  17 #include <apt-pkg/acquire.h>
  18 #include <apt-pkg/acquire-worker.h>
  19 #include <apt-pkg/acquire-item.h>
  20 #include <apt-pkg/configuration.h>
  21 #include <apt-pkg/error.h>
  22 #include <apt-pkg/fileutl.h>
  23 #include <apt-pkg/strutl.h>
  24 #include <apt-pkg/hashes.h>
  25
  26 #include <algorithm>
  27 #include <string>
  28 #include <vector>
  29 #include <iostream>
  30
  31 #include <sys/stat.h>
  32 #include <stdlib.h>
  33 #include <unistd.h>
  34 #include <signal.h>
  35 #include <stdio.h>
  36 #include <errno.h>
  37 #include <sstream>
  38
  39 #include <apti18n.h>
  40                                                                         /*}}}*/
  41
  42 using namespace std;
  43
  44 // Worker::Worker - Constructor for Queue startup                       /*{{{*/
  45 pkgAcquire::Worker::Worker(Queue *Q, MethodConfig *Cnf, pkgAcquireStatus *log) :
  46    d(NULL), OwnerQ(Q), Log(log), Config(Cnf), Access(Cnf->Access),
  47    CurrentItem(nullptr), CurrentSize(0), TotalSize(0)
  48 {
  49    Construct();
  50 }
  51                                                                         /*}}}*/
  52 // Worker::Worker - Constructor for method config startup               /*{{{*/
  53 pkgAcquire::Worker::Worker(MethodConfig *Cnf) : Worker(nullptr, Cnf, nullptr)
  54 {
  55 }
  56                                                                         /*}}}*/
  57 // Worker::Construct - Constructor helper                               /*{{{*/
  58 // ---------------------------------------------------------------------
  59 /* */
  60 void pkgAcquire::Worker::Construct()
  61 {
  62    NextQueue = 0;
  63    NextAcquire = 0;
  64    Process = -1;
  65    InFd = -1;
  66    OutFd = -1;
  67    OutReady = false;
  68    InReady = false;
  69    Debug = _config->FindB("Debug::pkgAcquire::Worker",false);
  70 }
  71                                                                         /*}}}*/
  72 // Worker::~Worker - Destructor                                         /*{{{*/
  73 // ---------------------------------------------------------------------
  74 /* */
  75 pkgAcquire::Worker::~Worker()
  76 {
  77    close(InFd);
  78    close(OutFd);
  79
  80    if (Process > 0)
  81    {
  82       /* Closing of stdin is the signal to exit and die when the process
  83          indicates it needs cleanup */
  84       if (Config->NeedsCleanup == false)
  85          kill(Process,SIGINT);
  86       ExecWait(Process,Access.c_str(),true);
  87    }
  88 }
  89                                                                         /*}}}*/
  90 // Worker::Start - Start the worker process                             /*{{{*/
  91 // ---------------------------------------------------------------------
  92 /* This forks the method and inits the communication channel */
  93 bool pkgAcquire::Worker::Start()
  94 {
  95    // Get the method path
  96    string Method = _config->FindDir("Dir::Bin::Methods") + Access;
  97    if (FileExists(Method) == false)
  98    {
  99       _error->Error(_("The method driver %s could not be found."),Method.c_str());
 100       if (Access == "https")
 101          _error->Notice(_("Is the package %s installed?"), "apt-transport-https");
 102       return false;
 103    }
 104
 105    if (Debug == true)
 106       clog << "Starting method '" << Method << '\'' << endl;
 107
 108    // Create the pipes
 109    int Pipes[4] = {-1,-1,-1,-1};
 110    if (pipe(Pipes) != 0 || pipe(Pipes+2) != 0)
 111    {
 112       _error->Errno("pipe","Failed to create IPC pipe to subprocess");
 113       for (int I = 0; I != 4; I++)
 114          close(Pipes[I]);
 115       return false;
 116    }
 117    for (int I = 0; I != 4; I++)
 118       SetCloseExec(Pipes[I],true);
 119
 120    // Fork off the process
 121    Process = ExecFork();
 122    if (Process == 0)
 123    {
 124       // Setup the FDs
 125       dup2(Pipes[1],STDOUT_FILENO);
 126       dup2(Pipes[2],STDIN_FILENO);
 127       SetCloseExec(STDOUT_FILENO,false);
 128       SetCloseExec(STDIN_FILENO,false);
 129       SetCloseExec(STDERR_FILENO,false);
 130
 131       const char *Args[2];
 132       Args[0] = Method.c_str();
 133       Args[1] = 0;
 134       execv(Args[0],(char **)Args);
 135       cerr << "Failed to exec method " << Args[0] << endl;
 136       _exit(100);
 137    }
 138
 139    // Fix up our FDs
 140    InFd = Pipes[0];
 141    OutFd = Pipes[3];
 142    SetNonBlock(Pipes[0],true);
 143    SetNonBlock(Pipes[3],true);
 144    close(Pipes[1]);
 145    close(Pipes[2]);
 146    OutReady = false;
 147    InReady = true;
 148
 149    // Read the configuration data
 150    if (WaitFd(InFd) == false ||
 151        ReadMessages() == false)
 152       return _error->Error(_("Method %s did not start correctly"),Method.c_str());
 153
 154    RunMessages();
 155    if (OwnerQ != 0)
 156       SendConfiguration();
 157
 158    return true;
 159 }
 160                                                                         /*}}}*/
 161 // Worker::ReadMessages - Read all pending messages into the list       /*{{{*/
 162 // ---------------------------------------------------------------------
 163 /* */
 164 bool pkgAcquire::Worker::ReadMessages()
 165 {
 166    if (::ReadMessages(InFd,MessageQueue) == false)
 167       return MethodFailure();
 168    return true;
 169 }
 170                                                                         /*}}}*/
 171 // Worker::RunMessage - Empty the message queue                         /*{{{*/
 172 // ---------------------------------------------------------------------
 173 /* This takes the messages from the message queue and runs them through
 174    the parsers in order. */
 175 enum class APT_HIDDEN MessageType {
 176    CAPABILITIES = 100,
 177    LOG = 101,
 178    STATUS = 102,
 179    REDIRECT = 103,
 180    WARNING = 104,
 181    URI_START = 200,
 182    URI_DONE = 201,
 183    URI_FAILURE = 400,
 184    GENERAL_FAILURE = 401,
 185    MEDIA_CHANGE = 403
 186 };
 187 static bool isDoomedItem(pkgAcquire::Item const * const Itm)
 188 {
 189    auto const TransItm = dynamic_cast<pkgAcqTransactionItem const * const>(Itm);
 190    if (TransItm == nullptr)
 191       return false;
 192    return TransItm->TransactionManager->State != pkgAcqTransactionItem::TransactionStarted;
 193 }
 194 bool pkgAcquire::Worker::RunMessages()
 195 {
 196    while (MessageQueue.empty() == false)
 197    {
 198       string Message = MessageQueue.front();
 199       MessageQueue.erase(MessageQueue.begin());
 200
 201       if (Debug == true)
 202          clog << " <- " << Access << ':' << QuoteString(Message,"\n") << endl;
 203
 204       // Fetch the message number
 205       char *End;
 206       MessageType const Number = static_cast<MessageType>(strtoul(Message.c_str(),&End,10));
 207       if (End == Message.c_str())
 208          return _error->Error("Invalid message from method %s: %s",Access.c_str(),Message.c_str());
 209
 210       string URI = LookupTag(Message,"URI");
 211       pkgAcquire::Queue::QItem *Itm = NULL;
 212       if (URI.empty() == false)
 213          Itm = OwnerQ->FindItem(URI,this);
 214
 215       if (Itm != NULL)
 216       {
 217          // update used mirror
 218          string UsedMirror = LookupTag(Message,"UsedMirror", "");
 219          if (UsedMirror.empty() == false)
 220          {
 221             for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
 222                (*O)->UsedMirror = UsedMirror;
 223
 224             if (Itm->Description.find(" ") != string::npos)
 225                Itm->Description.replace(0, Itm->Description.find(" "), UsedMirror);
 226          }
 227       }
 228
 229       // Determine the message number and dispatch
 230       switch (Number)
 231       {
 232          case MessageType::CAPABILITIES:
 233          if (Capabilities(Message) == false)
 234             return _error->Error("Unable to process Capabilities message from %s",Access.c_str());
 235          break;
 236
 237          case MessageType::LOG:
 238          if (Debug == true)
 239             clog << " <- (log) " << LookupTag(Message,"Message") << endl;
 240          break;
 241
 242          case MessageType::STATUS:
 243          Status = LookupTag(Message,"Message");
 244          break;
 245
 246          case MessageType::REDIRECT:
 247          {
 248             if (Itm == nullptr)
 249             {
 250                _error->Error("Method gave invalid 103 Redirect message");
 251                break;
 252             }
 253
 254             std::string const NewURI = LookupTag(Message,"New-URI",URI.c_str());
 255             Itm->URI = NewURI;
 256
 257             ItemDone();
 258
 259             // Change the status so that it can be dequeued
 260             for (auto const &O: Itm->Owners)
 261                O->Status = pkgAcquire::Item::StatIdle;
 262             // Mark the item as done (taking care of all queues)
 263             // and then put it in the main queue again
 264             std::vector<Item*> const ItmOwners = Itm->Owners;
 265             OwnerQ->ItemDone(Itm);
 266             Itm = nullptr;
 267             for (auto const &Owner: ItmOwners)
 268             {
 269                pkgAcquire::ItemDesc &desc = Owner->GetItemDesc();
 270                if (Log != nullptr)
 271                   Log->Done(desc);
 272
 273                // if we change site, treat it as a mirror change
 274                if (URI::SiteOnly(NewURI) != URI::SiteOnly(desc.URI))
 275                {
 276                   std::string const OldSite = desc.Description.substr(0, desc.Description.find(" "));
 277                   if (likely(APT::String::Startswith(desc.URI, OldSite)))
 278                   {
 279                      std::string const OldExtra = desc.URI.substr(OldSite.length() + 1);
 280                      if (likely(APT::String::Endswith(NewURI, OldExtra)))
 281                      {
 282                         std::string const NewSite = NewURI.substr(0, NewURI.length() - OldExtra.length());
 283                         Owner->UsedMirror = URI::ArchiveOnly(NewSite);
 284                         if (desc.Description.find(" ") != string::npos)
 285                            desc.Description.replace(0, desc.Description.find(" "), Owner->UsedMirror);
 286                      }
 287                   }
 288                }
 289                desc.URI = NewURI;
 290                if (isDoomedItem(Owner) == false)
 291                   OwnerQ->Owner->Enqueue(desc);
 292             }
 293             break;
 294          }
 295
 296          case MessageType::WARNING:
 297             _error->Warning("%s: %s", Itm->Owner->DescURI().c_str(), LookupTag(Message,"Message").c_str());
 298             break;
 299
 300          case MessageType::URI_START:
 301          {
 302             if (Itm == nullptr)
 303             {
 304                _error->Error("Method gave invalid 200 URI Start message");
 305                break;
 306             }
 307
 308             CurrentItem = Itm;
 309             CurrentSize = 0;
 310             TotalSize = strtoull(LookupTag(Message,"Size","0").c_str(), NULL, 10);
 311             ResumePoint = strtoull(LookupTag(Message,"Resume-Point","0").c_str(), NULL, 10);
 312             for (auto const Owner: Itm->Owners)
 313             {
 314                Owner->Start(Message, TotalSize);
 315                // Display update before completion
 316                if (Log != nullptr)
 317                {
 318                   if (Log->MorePulses == true)
 319                      Log->Pulse(Owner->GetOwner());
 320                   Log->Fetch(Owner->GetItemDesc());
 321                }
 322             }
 323
 324             break;
 325          }
 326
 327          case MessageType::URI_DONE:
 328          {
 329             if (Itm == nullptr)
 330             {
 331                _error->Error("Method gave invalid 201 URI Done message");
 332                break;
 333             }
 334
 335             PrepareFiles("201::URIDone", Itm);
 336
 337             // Display update before completion
 338             if (Log != 0 && Log->MorePulses == true)
 339                for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
 340                   Log->Pulse((*O)->GetOwner());
 341
 342             HashStringList ReceivedHashes;
 343             {
 344                std::string const givenfilename = LookupTag(Message, "Filename");
 345                std::string const filename = givenfilename.empty() ? Itm->Owner->DestFile : givenfilename;
 346                // see if we got hashes to verify
 347                for (char const * const * type = HashString::SupportedHashes(); *type != NULL; ++type)
 348                {
 349                   std::string const tagname = std::string(*type) + "-Hash";
 350                   std::string const hashsum = LookupTag(Message, tagname.c_str());
 351                   if (hashsum.empty() == false)
 352                      ReceivedHashes.push_back(HashString(*type, hashsum));
 353                }
 354                // not all methods always sent Hashes our way
 355                if (ReceivedHashes.usable() == false)
 356                {
 357                   HashStringList const ExpectedHashes = Itm->GetExpectedHashes();
 358                   if (ExpectedHashes.usable() == true && RealFileExists(filename))
 359                   {
 360                      Hashes calc(ExpectedHashes);
 361                      FileFd file(filename, FileFd::ReadOnly, FileFd::None);
 362                      calc.AddFD(file);
 363                      ReceivedHashes = calc.GetHashStringList();
 364                   }
 365                }
 366
 367                // only local files can refer other filenames and counting them as fetched would be unfair
 368                if (Log != NULL && Itm->Owner->Complete == false && Itm->Owner->Local == false && givenfilename == filename)
 369                   Log->Fetched(ReceivedHashes.FileSize(),atoi(LookupTag(Message,"Resume-Point","0").c_str()));
 370             }
 371
 372             std::vector<Item*> const ItmOwners = Itm->Owners;
 373             OwnerQ->ItemDone(Itm);
 374             Itm = NULL;
 375
 376             bool const isIMSHit = StringToBool(LookupTag(Message,"IMS-Hit"),false) ||
 377                StringToBool(LookupTag(Message,"Alt-IMS-Hit"),false);
 378             for (auto const Owner: ItmOwners)
 379             {
 380                HashStringList const ExpectedHashes = Owner->GetExpectedHashes();
 381                if(_config->FindB("Debug::pkgAcquire::Auth", false) == true)
 382                {
 383                   std::clog << "201 URI Done: " << Owner->DescURI() << endl
 384                      << "ReceivedHash:" << endl;
 385                   for (HashStringList::const_iterator hs = ReceivedHashes.begin(); hs != ReceivedHashes.end(); ++hs)
 386                      std::clog <<  "\t- " << hs->toStr() << std::endl;
 387                   std::clog << "ExpectedHash:" << endl;
 388                   for (HashStringList::const_iterator hs = ExpectedHashes.begin(); hs != ExpectedHashes.end(); ++hs)
 389                      std::clog <<  "\t- " << hs->toStr() << std::endl;
 390                   std::clog << endl;
 391                }
 392
 393                // decide if what we got is what we expected
 394                bool consideredOkay = false;
 395                if (ExpectedHashes.usable())
 396                {
 397                   if (ReceivedHashes.usable() == false)
 398                   {
 399                      /* IMS-Hits can't be checked here as we will have uncompressed file,
 400                         but the hashes for the compressed file. What we have was good through
 401                         so all we have to ensure later is that we are not stalled. */
 402                      consideredOkay = isIMSHit;
 403                   }
 404                   else if (ReceivedHashes == ExpectedHashes)
 405                      consideredOkay = true;
 406                   else
 407                      consideredOkay = false;
 408
 409                }
 410                else if (Owner->HashesRequired() == true)
 411                   consideredOkay = false;
 412                else
 413                {
 414                   consideredOkay = true;
 415                   // even if the hashes aren't usable to declare something secure
 416                   // we can at least use them to declare it an integrity failure
 417                   if (ExpectedHashes.empty() == false && ReceivedHashes != ExpectedHashes && _config->Find("Acquire::ForceHash").empty())
 418                      consideredOkay = false;
 419                }
 420
 421                if (consideredOkay == true)
 422                   consideredOkay = Owner->VerifyDone(Message, Config);
 423                else // hashsum mismatch
 424                   Owner->Status = pkgAcquire::Item::StatAuthError;
 425
 426
 427                if (consideredOkay == true)
 428                {
 429                   if (isDoomedItem(Owner) == false)
 430                      Owner->Done(Message, ReceivedHashes, Config);
 431                   if (Log != nullptr)
 432                   {
 433                      if (isIMSHit)
 434                         Log->IMSHit(Owner->GetItemDesc());
 435                      else
 436                         Log->Done(Owner->GetItemDesc());
 437                   }
 438                }
 439                else
 440                {
 441                   if (isDoomedItem(Owner) == false)
 442                   {
 443                      Message.append("\nFailReason: HashSumMismatch");
 444                      Owner->Failed(Message,Config);
 445                   }
 446                   if (Log != nullptr)
 447                      Log->Fail(Owner->GetItemDesc());
 448                }
 449             }
 450             ItemDone();
 451             break;
 452          }
 453
 454          case MessageType::URI_FAILURE:
 455          {
 456             if (Itm == nullptr)
 457             {
 458                std::string const msg = LookupTag(Message,"Message");
 459                _error->Error("Method gave invalid 400 URI Failure message: %s", msg.c_str());
 460                break;
 461             }
 462
 463             PrepareFiles("400::URIFailure", Itm);
 464
 465             // Display update before completion
 466             if (Log != nullptr && Log->MorePulses == true)
 467                for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
 468                   Log->Pulse((*O)->GetOwner());
 469
 470             std::vector<Item*> const ItmOwners = Itm->Owners;
 471             OwnerQ->ItemDone(Itm);
 472             Itm = nullptr;
 473
 474             bool errTransient;
 475             {
 476                std::string const failReason = LookupTag(Message, "FailReason");
 477                std::string const reasons[] = { "Timeout", "ConnectionRefused",
 478                   "ConnectionTimedOut", "ResolveFailure", "TmpResolveFailure" };
 479                errTransient = std::find(std::begin(reasons), std::end(reasons), failReason) != std::end(reasons);
 480             }
 481
 482             for (auto const Owner: ItmOwners)
 483             {
 484                if (errTransient)
 485                   Owner->Status = pkgAcquire::Item::StatTransientNetworkError;
 486                if (isDoomedItem(Owner) == false)
 487                   Owner->Failed(Message,Config);
 488                if (Log != nullptr)
 489                   Log->Fail(Owner->GetItemDesc());
 490             }
 491             ItemDone();
 492
 493             break;
 494          }
 495
 496          case MessageType::GENERAL_FAILURE:
 497          _error->Error("Method %s General failure: %s",Access.c_str(),LookupTag(Message,"Message").c_str());
 498          break;
 499
 500          case MessageType::MEDIA_CHANGE:
 501          MediaChange(Message);
 502          break;
 503       }
 504    }
 505    return true;
 506 }
 507                                                                         /*}}}*/
 508 // Worker::Capabilities - 100 Capabilities handler                      /*{{{*/
 509 // ---------------------------------------------------------------------
 510 /* This parses the capabilities message and dumps it into the configuration
 511    structure. */
 512 bool pkgAcquire::Worker::Capabilities(string Message)
 513 {
 514    if (Config == 0)
 515       return true;
 516
 517    Config->Version = LookupTag(Message,"Version");
 518    Config->SingleInstance = StringToBool(LookupTag(Message,"Single-Instance"),false);
 519    Config->Pipeline = StringToBool(LookupTag(Message,"Pipeline"),false);
 520    Config->SendConfig = StringToBool(LookupTag(Message,"Send-Config"),false);
 521    Config->LocalOnly = StringToBool(LookupTag(Message,"Local-Only"),false);
 522    Config->NeedsCleanup = StringToBool(LookupTag(Message,"Needs-Cleanup"),false);
 523    Config->Removable = StringToBool(LookupTag(Message,"Removable"),false);
 524
 525    // Some debug text
 526    if (Debug == true)
 527    {
 528       clog << "Configured access method " << Config->Access << endl;
 529       clog << "Version:" << Config->Version <<
 530               " SingleInstance:" << Config->SingleInstance <<
 531               " Pipeline:" << Config->Pipeline <<
 532               " SendConfig:" << Config->SendConfig <<
 533               " LocalOnly: " << Config->LocalOnly <<
 534               " NeedsCleanup: " << Config->NeedsCleanup <<
 535               " Removable: " << Config->Removable << endl;
 536    }
 537
 538    return true;
 539 }
 540                                                                         /*}}}*/
 541 // Worker::MediaChange - Request a media change                         /*{{{*/
 542 // ---------------------------------------------------------------------
 543 /* */
 544 bool pkgAcquire::Worker::MediaChange(string Message)
 545 {
 546    int status_fd = _config->FindI("APT::Status-Fd",-1);
 547    if(status_fd > 0)
 548    {
 549       string Media = LookupTag(Message,"Media");
 550       string Drive = LookupTag(Message,"Drive");
 551       ostringstream msg,status;
 552       ioprintf(msg,_("Please insert the disc labeled: "
 553                      "'%s' "
 554                      "in the drive '%s' and press [Enter]."),
 555                Media.c_str(),Drive.c_str());
 556       status << "media-change: "  // message
 557              << Media  << ":"     // media
 558              << Drive  << ":"     // drive
 559              << msg.str()         // l10n message
 560              << endl;
 561
 562       std::string const dlstatus = status.str();
 563       FileFd::Write(status_fd, dlstatus.c_str(), dlstatus.size());
 564    }
 565
 566    if (Log == 0 || Log->MediaChange(LookupTag(Message,"Media"),
 567                                     LookupTag(Message,"Drive")) == false)
 568    {
 569       char S[300];
 570       snprintf(S,sizeof(S),"603 Media Changed\nFailed: true\n\n");
 571       if (Debug == true)
 572          clog << " -> " << Access << ':' << QuoteString(S,"\n") << endl;
 573       OutQueue += S;
 574       OutReady = true;
 575       return true;
 576    }
 577
 578    char S[300];
 579    snprintf(S,sizeof(S),"603 Media Changed\n\n");
 580    if (Debug == true)
 581       clog << " -> " << Access << ':' << QuoteString(S,"\n") << endl;
 582    OutQueue += S;
 583    OutReady = true;
 584    return true;
 585 }
 586                                                                         /*}}}*/
 587 // Worker::SendConfiguration - Send the config to the method            /*{{{*/
 588 // ---------------------------------------------------------------------
 589 /* */
 590 bool pkgAcquire::Worker::SendConfiguration()
 591 {
 592    if (Config->SendConfig == false)
 593       return true;
 594
 595    if (OutFd == -1)
 596       return false;
 597
 598    /* Write out all of the configuration directives by walking the
 599       configuration tree */
 600    std::ostringstream Message;
 601    Message << "601 Configuration\n";
 602    _config->Dump(Message, NULL, "Config-Item: %F=%V\n", false);
 603    Message << '\n';
 604
 605    if (Debug == true)
 606       clog << " -> " << Access << ':' << QuoteString(Message.str(),"\n") << endl;
 607    OutQueue += Message.str();
 608    OutReady = true;
 609
 610    return true;
 611 }
 612                                                                         /*}}}*/
 613 // Worker::QueueItem - Add an item to the outbound queue                /*{{{*/
 614 // ---------------------------------------------------------------------
 615 /* Send a URI Acquire message to the method */
 616 bool pkgAcquire::Worker::QueueItem(pkgAcquire::Queue::QItem *Item)
 617 {
 618    if (OutFd == -1)
 619       return false;
 620
 621    string Message = "600 URI Acquire\n";
 622    Message.reserve(300);
 623    Message += "URI: " + Item->URI;
 624    Message += "\nFilename: " + Item->Owner->DestFile;
 625
 626    HashStringList const hsl = Item->GetExpectedHashes();
 627    for (HashStringList::const_iterator hs = hsl.begin(); hs != hsl.end(); ++hs)
 628       Message += "\nExpected-" + hs->HashType() + ": " + hs->HashValue();
 629
 630    if (hsl.FileSize() == 0)
 631    {
 632       unsigned long long FileSize = Item->GetMaximumSize();
 633       if(FileSize > 0)
 634       {
 635          string MaximumSize;
 636          strprintf(MaximumSize, "%llu", FileSize);
 637          Message += "\nMaximum-Size: " + MaximumSize;
 638       }
 639    }
 640
 641    Item->SyncDestinationFiles();
 642    Message += Item->Custom600Headers();
 643    Message += "\n\n";
 644
 645    if (RealFileExists(Item->Owner->DestFile))
 646    {
 647       std::string const SandboxUser = _config->Find("APT::Sandbox::User");
 648       ChangeOwnerAndPermissionOfFile("Item::QueueURI", Item->Owner->DestFile.c_str(),
 649                                      SandboxUser.c_str(), "root", 0600);
 650    }
 651
 652    if (Debug == true)
 653       clog << " -> " << Access << ':' << QuoteString(Message,"\n") << endl;
 654    OutQueue += Message;
 655    OutReady = true;
 656
 657    return true;
 658 }
 659                                                                         /*}}}*/
 660 // Worker::OutFdRead - Out bound FD is ready                            /*{{{*/
 661 // ---------------------------------------------------------------------
 662 /* */
 663 bool pkgAcquire::Worker::OutFdReady()
 664 {
 665    int Res;
 666    do
 667    {
 668       Res = write(OutFd,OutQueue.c_str(),OutQueue.length());
 669    }
 670    while (Res < 0 && errno == EINTR);
 671
 672    if (Res <= 0)
 673       return MethodFailure();
 674
 675    OutQueue.erase(0,Res);
 676    if (OutQueue.empty() == true)
 677       OutReady = false;
 678
 679    return true;
 680 }
 681                                                                         /*}}}*/
 682 // Worker::InFdRead - In bound FD is ready                              /*{{{*/
 683 // ---------------------------------------------------------------------
 684 /* */
 685 bool pkgAcquire::Worker::InFdReady()
 686 {
 687    if (ReadMessages() == false)
 688       return false;
 689    RunMessages();
 690    return true;
 691 }
 692                                                                         /*}}}*/
 693 // Worker::MethodFailure - Called when the method fails                 /*{{{*/
 694 // ---------------------------------------------------------------------
 695 /* This is called when the method is believed to have failed, probably because
 696    read returned -1. */
 697 bool pkgAcquire::Worker::MethodFailure()
 698 {
 699    _error->Error("Method %s has died unexpectedly!",Access.c_str());
 700
 701    // do not reap the child here to show meaningfull error to the user
 702    ExecWait(Process,Access.c_str(),false);
 703    Process = -1;
 704    close(InFd);
 705    close(OutFd);
 706    InFd = -1;
 707    OutFd = -1;
 708    OutReady = false;
 709    InReady = false;
 710    OutQueue = string();
 711    MessageQueue.erase(MessageQueue.begin(),MessageQueue.end());
 712
 713    return false;
 714 }
 715                                                                         /*}}}*/
 716 // Worker::Pulse - Called periodically                                  /*{{{*/
 717 // ---------------------------------------------------------------------
 718 /* */
 719 void pkgAcquire::Worker::Pulse()
 720 {
 721    if (CurrentItem == 0)
 722       return;
 723
 724    struct stat Buf;
 725    if (stat(CurrentItem->Owner->DestFile.c_str(),&Buf) != 0)
 726       return;
 727    CurrentSize = Buf.st_size;
 728 }
 729                                                                         /*}}}*/
 730 // Worker::ItemDone - Called when the current item is finished          /*{{{*/
 731 // ---------------------------------------------------------------------
 732 /* */
 733 void pkgAcquire::Worker::ItemDone()
 734 {
 735    CurrentItem = 0;
 736    CurrentSize = 0;
 737    TotalSize = 0;
 738    Status = string();
 739 }
 740                                                                         /*}}}*/
 741 void pkgAcquire::Worker::PrepareFiles(char const * const caller, pkgAcquire::Queue::QItem const * const Itm)/*{{{*/
 742 {
 743    if (RealFileExists(Itm->Owner->DestFile))
 744    {
 745       ChangeOwnerAndPermissionOfFile(caller, Itm->Owner->DestFile.c_str(), "root", "root", 0644);
 746       std::string const filename = Itm->Owner->DestFile;
 747       for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
 748       {
 749          pkgAcquire::Item const * const Owner = *O;
 750          if (Owner->DestFile == filename || filename == "/dev/null")
 751             continue;
 752          RemoveFile("PrepareFiles", Owner->DestFile);
 753          if (link(filename.c_str(), Owner->DestFile.c_str()) != 0)
 754          {
 755             // different mounts can't happen for us as we download to lists/ by default,
 756             // but if the system is reused by others the locations can potentially be on
 757             // different disks, so use symlink as poor-men replacement.
 758             // FIXME: Real copying as last fallback, but that is costly, so offload to a method preferable
 759             if (symlink(filename.c_str(), Owner->DestFile.c_str()) != 0)
 760                _error->Error("Can't create (sym)link of file %s to %s", filename.c_str(), Owner->DestFile.c_str());
 761          }
 762       }
 763    }
 764    else
 765    {
 766       for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
 767          RemoveFile("PrepareFiles", (*O)->DestFile);
 768    }
 769 }
 770                                                                         /*}}}*/