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