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