summaryrefslogtreecommitdiff
path: root/apt-pkg/packagemanager.cc
blob: b93bf6ab9e5fb2302c24a5e70838d6448fcd7352 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
// -*- mode: cpp; mode: fold -*-
// Description								/*{{{*/
// $Id: packagemanager.cc,v 1.30 2003/04/27 03:04:15 doogie Exp $
/* ######################################################################

   Package Manager - Abstacts the package manager

   More work is needed in the area of transitioning provides, ie exim
   replacing smail. This can cause interesing side effects.

   Other cases involving conflicts+replaces should be tested. 
   
   ##################################################################### */
									/*}}}*/
// Include Files							/*{{{*/
#include<config.h>

#include <apt-pkg/packagemanager.h>
#include <apt-pkg/orderlist.h>
#include <apt-pkg/depcache.h>
#include <apt-pkg/error.h>
#include <apt-pkg/version.h>
#include <apt-pkg/acquire-item.h>
#include <apt-pkg/algorithms.h>
#include <apt-pkg/configuration.h>
#include <apt-pkg/sptr.h>

#include <iostream>
#include <fcntl.h>

#include <apti18n.h>
									/*}}}*/
using namespace std;

bool pkgPackageManager::SigINTStop = false;

// PM::PackageManager - Constructor					/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgPackageManager::pkgPackageManager(pkgDepCache *pCache) : Cache(*pCache),
							    List(NULL), Res(Incomplete)
{
   FileNames = new string[Cache.Head().PackageCount];
   Debug = _config->FindB("Debug::pkgPackageManager",false);
   NoImmConfigure = !_config->FindB("APT::Immediate-Configure",true);
   ImmConfigureAll = _config->FindB("APT::Immediate-Configure-All",false);
}
									/*}}}*/
// PM::PackageManager - Destructor					/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgPackageManager::~pkgPackageManager()
{
   delete List;
   delete [] FileNames;
}
									/*}}}*/
// PM::GetArchives - Queue the archives for download			/*{{{*/
// ---------------------------------------------------------------------
/* */
bool pkgPackageManager::GetArchives(pkgAcquire *Owner,pkgSourceList *Sources,
				    pkgRecords *Recs)
{
   if (CreateOrderList() == false)
      return false;
   
   bool const ordering =
	_config->FindB("PackageManager::UnpackAll",true) ?
		List->OrderUnpack() : List->OrderCritical();
   if (ordering == false)
      return _error->Error("Internal ordering error");

   for (pkgOrderList::iterator I = List->begin(); I != List->end(); ++I)
   {
      PkgIterator Pkg(Cache,*I);
      FileNames[Pkg->ID] = string();
      
      // Skip packages to erase
      if (Cache[Pkg].Delete() == true)
	 continue;

      // Skip Packages that need configure only.
      if (Pkg.State() == pkgCache::PkgIterator::NeedsConfigure && 
	  Cache[Pkg].Keep() == true)
	 continue;

      // Skip already processed packages
      if (List->IsNow(Pkg) == false)
	 continue;

      new pkgAcqArchive(Owner,Sources,Recs,Cache[Pkg].InstVerIter(Cache),
			FileNames[Pkg->ID]);
   }

   return true;
}
									/*}}}*/
// PM::FixMissing - Keep all missing packages				/*{{{*/
// ---------------------------------------------------------------------
/* This is called to correct the installation when packages could not
   be downloaded. */
bool pkgPackageManager::FixMissing()
{   
   pkgDepCache::ActionGroup group(Cache);
   pkgProblemResolver Resolve(&Cache);
   List->SetFileList(FileNames);

   bool Bad = false;
   for (PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
   {
      if (List->IsMissing(I) == false)
	 continue;
   
      // Okay, this file is missing and we need it. Mark it for keep 
      Bad = true;
      Cache.MarkKeep(I, false, false);
   }
 
   // We have to empty the list otherwise it will not have the new changes
   delete List;
   List = 0;
   
   if (Bad == false)
      return true;
   
   // Now downgrade everything that is broken
   return Resolve.ResolveByKeep() == true && Cache.BrokenCount() == 0;   
}
									/*}}}*/
// PM::ImmediateAdd - Add the immediate flag recursivly			/*{{{*/
// ---------------------------------------------------------------------
/* This adds the immediate flag to the pkg and recursively to the
   dependendies 
 */
void pkgPackageManager::ImmediateAdd(PkgIterator I, bool UseInstallVer, unsigned const int &Depth)
{
   DepIterator D;
   
   if(UseInstallVer)
   {
      if(Cache[I].InstallVer == 0)
	 return;
      D = Cache[I].InstVerIter(Cache).DependsList(); 
   } else {
      if (I->CurrentVer == 0)
	 return;
      D = I.CurrentVer().DependsList(); 
   }

   for ( /* nothing */  ; D.end() == false; ++D)
      if (D->Type == pkgCache::Dep::Depends || D->Type == pkgCache::Dep::PreDepends)
      {
	 if(!List->IsFlag(D.TargetPkg(), pkgOrderList::Immediate))
	 {
	    if(Debug)
	       clog << OutputInDepth(Depth) << "ImmediateAdd(): Adding Immediate flag to " << D.TargetPkg() << " cause of " << D.DepType() << " " << I.FullName() << endl;
	    List->Flag(D.TargetPkg(),pkgOrderList::Immediate);
	    ImmediateAdd(D.TargetPkg(), UseInstallVer, Depth + 1);
	 }
      }
   return;
}
									/*}}}*/
// PM::CreateOrderList - Create the ordering class			/*{{{*/
// ---------------------------------------------------------------------
/* This populates the ordering list with all the packages that are
   going to change. */
bool pkgPackageManager::CreateOrderList()
{
   if (List != 0)
      return true;
   
   delete List;
   List = new pkgOrderList(&Cache);

   if (Debug && ImmConfigureAll) 
      clog << "CreateOrderList(): Adding Immediate flag for all packages because of APT::Immediate-Configure-All" << endl;
   
   // Generate the list of affected packages and sort it
   for (PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
   {
      // Ignore no-version packages
      if (I->VersionList == 0)
	 continue;
      
      // Mark the package and its dependends for immediate configuration
      if ((((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential) &&
	  NoImmConfigure == false) || ImmConfigureAll)
      {
	 if(Debug && !ImmConfigureAll)
	    clog << "CreateOrderList(): Adding Immediate flag for " << I.FullName() << endl;
	 List->Flag(I,pkgOrderList::Immediate);
	 
	 if (!ImmConfigureAll) {
	    // Look for other install packages to make immediate configurea
	    ImmediateAdd(I, true);
	  
	    // And again with the current version.
	    ImmediateAdd(I, false);
	 }
      }
      
      // Not interesting
      if ((Cache[I].Keep() == true || 
	  Cache[I].InstVerIter(Cache) == I.CurrentVer()) && 
	  I.State() == pkgCache::PkgIterator::NeedsNothing &&
	  (Cache[I].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall &&
	  (I.Purge() != false || Cache[I].Mode != pkgDepCache::ModeDelete ||
	   (Cache[I].iFlags & pkgDepCache::Purge) != pkgDepCache::Purge))
	 continue;
      
      // Append it to the list
      List->push_back(I);      
   }
   
   return true;
}
									/*}}}*/
// PM::DepAlwaysTrue - Returns true if this dep is irrelevent		/*{{{*/
// ---------------------------------------------------------------------
/* The restriction on provides is to eliminate the case when provides
   are transitioning between valid states [ie exim to smail] */
bool pkgPackageManager::DepAlwaysTrue(DepIterator D)
{
   if (D.TargetPkg()->ProvidesList != 0)
      return false;
   
   if ((Cache[D] & pkgDepCache::DepInstall) != 0 &&
       (Cache[D] & pkgDepCache::DepNow) != 0)
      return true;
   return false;
}
									/*}}}*/
// PM::CheckRConflicts - Look for reverse conflicts			/*{{{*/
// ---------------------------------------------------------------------
/* This looks over the reverses for a conflicts line that needs early
   removal. */
bool pkgPackageManager::CheckRConflicts(PkgIterator Pkg,DepIterator D,
					const char *Ver)
{
   for (;D.end() == false; ++D)
   {
      if (D->Type != pkgCache::Dep::Conflicts &&
	  D->Type != pkgCache::Dep::Obsoletes)
	 continue;

      // The package hasnt been changed
      if (List->IsNow(Pkg) == false)
	 continue;
      
      // Ignore self conflicts, ignore conflicts from irrelevent versions
      if (D.IsIgnorable(Pkg) || D.ParentVer() != D.ParentPkg().CurrentVer())
	 continue;
      
      if (Cache.VS().CheckDep(Ver,D->CompareOp,D.TargetVer()) == false)
	 continue;

      if (EarlyRemove(D.ParentPkg()) == false)
	 return _error->Error("Reverse conflicts early remove for package '%s' failed",
			      Pkg.FullName().c_str());
   }
   return true;
}
									/*}}}*/
// PM::ConfigureAll - Run the all out configuration			/*{{{*/
// ---------------------------------------------------------------------
/* This configures every package. It is assumed they are all unpacked and
   that the final configuration is valid. This is also used to catch packages
   that have not been configured when using ImmConfigureAll */
bool pkgPackageManager::ConfigureAll()
{
   pkgOrderList OList(&Cache);
   
   // Populate the order list
   for (pkgOrderList::iterator I = List->begin(); I != List->end(); ++I)
      if (List->IsFlag(pkgCache::PkgIterator(Cache,*I),
		       pkgOrderList::UnPacked) == true)
	 OList.push_back(*I);
   
   if (OList.OrderConfigure() == false)
      return false;

   std::string const conf = _config->Find("PackageManager::Configure","all");
   bool const ConfigurePkgs = (conf == "all");

   // Perform the configuring
   for (pkgOrderList::iterator I = OList.begin(); I != OList.end(); ++I)
   {
      PkgIterator Pkg(Cache,*I);
      
      /* Check if the package has been configured, this can happen if SmartConfigure
         calls its self */ 
      if (List->IsFlag(Pkg,pkgOrderList::Configured)) continue;

      if (ConfigurePkgs == true && SmartConfigure(Pkg, 0) == false) {
         if (ImmConfigureAll)
            _error->Error(_("Could not perform immediate configuration on '%s'. "
			"Please see man 5 apt.conf under APT::Immediate-Configure for details. (%d)"),Pkg.FullName().c_str(),1);
         else
            _error->Error("Internal error, packages left unconfigured. %s",Pkg.FullName().c_str());
	 return false;
      }
      
      List->Flag(Pkg,pkgOrderList::Configured,pkgOrderList::States);
   }
   
   return true;
}
									/*}}}*/
// PM::SmartConfigure - Perform immediate configuration of the pkg	/*{{{*/
// ---------------------------------------------------------------------
/* This function tries to put the system in a state where Pkg can be configured.
   This involves checking each of Pkg's dependanies and unpacking and 
   configuring packages where needed. 
   
   Note on failure: This method can fail, without causing any problems. 
   This can happen when using Immediate-Configure-All, SmartUnPack may call
   SmartConfigure, it may fail because of a complex dependancy situation, but
   a error will only be reported if ConfigureAll fails. This is why some of the
   messages this function reports on failure (return false;) as just warnings
   only shown when debuging*/
bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
{
   // If this is true, only check and correct and dependencies without the Loop flag
   bool const PkgLoop = List->IsFlag(Pkg,pkgOrderList::Loop);

   if (Debug) {
      VerIterator InstallVer = VerIterator(Cache,Cache[Pkg].InstallVer);
      clog << OutputInDepth(Depth) << "SmartConfigure " << Pkg.FullName() << " (" << InstallVer.VerStr() << ")";
      if (PkgLoop)
        clog << " (Only Correct Dependencies)";
      clog << endl;
   }

   VerIterator const instVer = Cache[Pkg].InstVerIter(Cache);
      
   /* Because of the ordered list, most dependencies should be unpacked, 
      however if there is a loop (A depends on B, B depends on A) this will not 
      be the case, so check for dependencies before configuring. */
   bool Bad = false, Changed = false;
   const unsigned int max_loops = _config->FindI("APT::pkgPackageManager::MaxLoopCount", 500);
   unsigned int i=0;
   do
   {
      Changed = false;
      for (DepIterator D = instVer.DependsList(); D.end() == false; )
      {
	 // Compute a single dependency element (glob or)
	 pkgCache::DepIterator Start, End;
	 D.GlobOr(Start,End);

	 if (End->Type != pkgCache::Dep::Depends)
	    continue;
	 Bad = true;

	 // Search for dependencies which are unpacked but aren't configured yet (maybe loops)
	 for (DepIterator Cur = Start; true; ++Cur)
	 {
	    SPtrArray<Version *> VList = Cur.AllTargets();

	    for (Version **I = VList; *I != 0; ++I)
	    {
	       VerIterator Ver(Cache,*I);
	       PkgIterator DepPkg = Ver.ParentPkg();

	       // Check if the current version of the package is available and will satisfy this dependency
	       if (DepPkg.CurrentVer() == Ver && List->IsNow(DepPkg) == true &&
		   List->IsFlag(DepPkg,pkgOrderList::Removed) == false &&
		   DepPkg.State() == PkgIterator::NeedsNothing)
	       {
		  Bad = false;
		  break;
	       }

	       // Check if the version that is going to be installed will satisfy the dependency
	       if (Cache[DepPkg].InstallVer != *I)
		  continue;

	       if (List->IsFlag(DepPkg,pkgOrderList::UnPacked))
	       {
		  if (List->IsFlag(DepPkg,pkgOrderList::Loop) && PkgLoop)
		  {
		    // This dependency has already been dealt with by another SmartConfigure on Pkg
		    Bad = false;
		    break;
		  }
		  /* Check for a loop to prevent one forming
		       If A depends on B and B depends on A, SmartConfigure will
		       just hop between them if this is not checked. Dont remove the
		       loop flag after finishing however as loop is already set.
		       This means that there is another SmartConfigure call for this
		       package and it will remove the loop flag */
		  if (PkgLoop == false)
		     List->Flag(Pkg,pkgOrderList::Loop);
		  if (SmartConfigure(DepPkg, Depth + 1) == true)
		  {
		     Bad = false;
		     if (List->IsFlag(DepPkg,pkgOrderList::Loop) == false)
			Changed = true;
		  }
		  if (PkgLoop == false)
		    List->RmFlag(Pkg,pkgOrderList::Loop);
		  // If SmartConfigure was succesfull, Bad is false, so break
		  if (Bad == false)
		     break;
	       }
	       else if (List->IsFlag(DepPkg,pkgOrderList::Configured))
	       {
		  Bad = false;
		  break;
	       }
	    }
	    if (Cur == End)
	       break;
         }

	 if (Bad == false)
	    continue;

	 // Check for dependencies that have not been unpacked, probably due to loops.
	 for (DepIterator Cur = Start; true; ++Cur)
	 {
	    SPtrArray<Version *> VList = Cur.AllTargets();

	    for (Version **I = VList; *I != 0; ++I)
	    {
	       VerIterator Ver(Cache,*I);
	       PkgIterator DepPkg = Ver.ParentPkg();

	       // Check if the version that is going to be installed will satisfy the dependency
	       if (Cache[DepPkg].InstallVer != *I || List->IsNow(DepPkg) == false)
		  continue;

	       if (PkgLoop == true)
	       {
		  if (Debug)
		     std::clog << OutputInDepth(Depth) << "Package " << Pkg << " loops in SmartConfigure" << std::endl;
	          Bad = false;
		  break;
	       }
	       else
	       {
		  if (Debug)
		     clog << OutputInDepth(Depth) << "Unpacking " << DepPkg.FullName() << " to avoid loop " << Cur << endl;
		  if (PkgLoop == false)
		     List->Flag(Pkg,pkgOrderList::Loop);
		  if (SmartUnPack(DepPkg, true, Depth + 1) == true)
		  {
		     Bad = false;
		     if (List->IsFlag(DepPkg,pkgOrderList::Loop) == false)
		        Changed = true;
		  }
		  if (PkgLoop == false)
		     List->RmFlag(Pkg,pkgOrderList::Loop);
		  if (Bad == false)
		     break;
	       }
	    }

	    if (Cur == End)
	       break;
	 }

	 if (Bad == true && Changed == false && Debug == true)
	    std::clog << OutputInDepth(Depth) << "Could not satisfy " << Start << std::endl;
      }
      if (i++ > max_loops)
         return _error->Error("Internal error: MaxLoopCount reached in SmartUnPack for %s, aborting", Pkg.FullName().c_str());
   } while (Changed == true);
   
   if (Bad) {
      if (Debug)
         _error->Warning(_("Could not configure '%s'. "),Pkg.FullName().c_str());
      return false;
   }
   
   if (PkgLoop) return true;

   static std::string const conf = _config->Find("PackageManager::Configure","all");
   static bool const ConfigurePkgs = (conf == "all" || conf == "smart");

   if (List->IsFlag(Pkg,pkgOrderList::Configured)) 
      return _error->Error("Internal configure error on '%s'.", Pkg.FullName().c_str());

   if (ConfigurePkgs == true && Configure(Pkg) == false)
      return false;

   List->Flag(Pkg,pkgOrderList::Configured,pkgOrderList::States);

   if ((Cache[Pkg].InstVerIter(Cache)->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
      for (PkgIterator P = Pkg.Group().PackageList();
	   P.end() == false; P = Pkg.Group().NextPkg(P))
      {
	 if (Pkg == P || List->IsFlag(P,pkgOrderList::Configured) == true ||
	     Cache[P].InstallVer == 0 || (P.CurrentVer() == Cache[P].InstallVer &&
	      (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall))
	    continue;
	 SmartConfigure(P, (Depth +1));
      }

   // Sanity Check
   if (List->IsFlag(Pkg,pkgOrderList::Configured) == false)
      return _error->Error(_("Could not configure '%s'. "),Pkg.FullName().c_str());

   return true;
}
									/*}}}*/
// PM::EarlyRemove - Perform removal of packages before their time	/*{{{*/
// ---------------------------------------------------------------------
/* This is called to deal with conflicts arising from unpacking */
bool pkgPackageManager::EarlyRemove(PkgIterator Pkg)
{
   if (List->IsNow(Pkg) == false)
      return true;
	 
   // Already removed it
   if (List->IsFlag(Pkg,pkgOrderList::Removed) == true)
      return true;
   
   // Woops, it will not be re-installed!
   if (List->IsFlag(Pkg,pkgOrderList::InList) == false)
      return false;

   // Essential packages get special treatment
   bool IsEssential = false;
   if ((Pkg->Flags & pkgCache::Flag::Essential) != 0 ||
       (Pkg->Flags & pkgCache::Flag::Important) != 0)
      IsEssential = true;

   /* Check for packages that are the dependents of essential packages and 
      promote them too */
   if (Pkg->CurrentVer != 0)
   {
      for (DepIterator D = Pkg.RevDependsList(); D.end() == false &&
	   IsEssential == false; ++D)
	 if (D->Type == pkgCache::Dep::Depends || D->Type == pkgCache::Dep::PreDepends)
	    if ((D.ParentPkg()->Flags & pkgCache::Flag::Essential) != 0 ||
	        (D.ParentPkg()->Flags & pkgCache::Flag::Important) != 0)
	       IsEssential = true;
   }

   if (IsEssential == true)
   {
      if (_config->FindB("APT::Force-LoopBreak",false) == false)
	 return _error->Error(_("This installation run will require temporarily "
				"removing the essential package %s due to a "
				"Conflicts/Pre-Depends loop. This is often bad, "
				"but if you really want to do it, activate the "
				"APT::Force-LoopBreak option."),Pkg.FullName().c_str());
   }
   
   bool Res = SmartRemove(Pkg);
   if (Cache[Pkg].Delete() == false)
      List->Flag(Pkg,pkgOrderList::Removed,pkgOrderList::States);
   
   return Res;
}
									/*}}}*/
// PM::SmartRemove - Removal Helper					/*{{{*/
// ---------------------------------------------------------------------
/* */
bool pkgPackageManager::SmartRemove(PkgIterator Pkg)
{
   if (List->IsNow(Pkg) == false)
      return true;

   List->Flag(Pkg,pkgOrderList::Configured,pkgOrderList::States);

   return Remove(Pkg,(Cache[Pkg].iFlags & pkgDepCache::Purge) == pkgDepCache::Purge);
}
									/*}}}*/
// PM::SmartUnPack - Install helper					/*{{{*/
// ---------------------------------------------------------------------
/* This puts the system in a state where it can Unpack Pkg, if Pkg is allready
   unpacked, or when it has been unpacked, if Immediate==true it configures it. */
bool pkgPackageManager::SmartUnPack(PkgIterator Pkg)
{
   return SmartUnPack(Pkg, true, 0);
}
bool pkgPackageManager::SmartUnPack(PkgIterator Pkg, bool const Immediate, int const Depth)
{
   bool PkgLoop = List->IsFlag(Pkg,pkgOrderList::Loop);

   if (Debug) {
      clog << OutputInDepth(Depth) << "SmartUnPack " << Pkg.FullName();
      VerIterator InstallVer = VerIterator(Cache,Cache[Pkg].InstallVer);
      if (Pkg.CurrentVer() == 0)
        clog << " (install version " << InstallVer.VerStr() << ")";
      else
        clog << " (replace version " << Pkg.CurrentVer().VerStr() << " with " << InstallVer.VerStr() << ")";
      if (PkgLoop)
        clog << " (Only Perform PreUnpack Checks)";
      clog << endl;
   }

   VerIterator const instVer = Cache[Pkg].InstVerIter(Cache);

   /* PreUnpack Checks: This loop checks and attempts to rectify and problems that would prevent the package being unpacked.
      It addresses: PreDepends, Conflicts, Obsoletes and Breaks (DpkgBreaks). Any resolutions that do not require it should
      avoid configuration (calling SmartUnpack with Immediate=true), this is because when unpacking some packages with
      complex dependancy structures, trying to configure some packages while breaking the loops can complicate things .
      This will be either dealt with if the package is configured as a dependency of Pkg (if and when Pkg is configured),
      or by the ConfigureAll call at the end of the for loop in OrderInstall. */
   bool Changed = false;
   const unsigned int max_loops = _config->FindI("APT::pkgPackageManager::MaxLoopCount", 500);
   unsigned int i = 0;
   do 
   {
      Changed = false;
      for (DepIterator D = instVer.DependsList(); D.end() == false; )
      {
	 // Compute a single dependency element (glob or)
	 pkgCache::DepIterator Start, End;
	 D.GlobOr(Start,End);

	 if (End->Type == pkgCache::Dep::PreDepends)
         {
	    bool Bad = true;
	    if (Debug)
	       clog << OutputInDepth(Depth) << "PreDepends order for " << Pkg.FullName() << std::endl;

	    // Look for easy targets: packages that are already okay
	    for (DepIterator Cur = Start; Bad == true; ++Cur)
	    {
	       SPtrArray<Version *> VList = Cur.AllTargets();
	       for (Version **I = VList; *I != 0; ++I)
	       {
		  VerIterator Ver(Cache,*I);
		  PkgIterator Pkg = Ver.ParentPkg();

		  // See if the current version is ok
		  if (Pkg.CurrentVer() == Ver && List->IsNow(Pkg) == true &&
		      Pkg.State() == PkgIterator::NeedsNothing)
		  {
		     Bad = false;
		     if (Debug)
			clog << OutputInDepth(Depth) << "Found ok package " << Pkg.FullName() << endl;
		     break;
		  }
	       }
	       if (Cur == End)
		  break;
	    }

	    // Look for something that could be configured.
	    for (DepIterator Cur = Start; Bad == true && Cur.end() == false; ++Cur)
	    {
	       SPtrArray<Version *> VList = Cur.AllTargets();
	       for (Version **I = VList; *I != 0; ++I)
	       {
		  VerIterator Ver(Cache,*I);
		  PkgIterator Pkg = Ver.ParentPkg();

		  // Not the install version
		  if (Cache[Pkg].InstallVer != *I ||
		      (Cache[Pkg].Keep() == true && Pkg.State() == PkgIterator::NeedsNothing))
		     continue;

		  if (List->IsFlag(Pkg,pkgOrderList::Configured))
		  {
		     Bad = false;
		     break;
		  }

		  // check if it needs unpack or if if configure is enough
		  if (List->IsFlag(Pkg,pkgOrderList::UnPacked) == false)
		  {
		     if (Debug)
			clog << OutputInDepth(Depth) << "Trying to SmartUnpack " << Pkg.FullName() << endl;
		     // SmartUnpack with the ImmediateFlag to ensure its really ready
		     if (SmartUnPack(Pkg, true, Depth + 1) == true)
		     {
			Bad = false;
			if (List->IsFlag(Pkg,pkgOrderList::Loop) == false)
			   Changed = true;
			break;
		     }
		  }
		  else
		  {
		     if (Debug)
			clog << OutputInDepth(Depth) << "Trying to SmartConfigure " << Pkg.FullName() << endl;
		     if (SmartConfigure(Pkg, Depth + 1) == true)
		     {
			Bad = false;
			if (List->IsFlag(Pkg,pkgOrderList::Loop) == false)
			   Changed = true;
			break;
		     }
		  }
	       }
	    }

	    if (Bad == true)
	    {
	       if (Start == End)
		  return _error->Error("Couldn't configure pre-depend %s for %s, "
					"probably a dependency cycle.",
					End.TargetPkg().FullName().c_str(),Pkg.FullName().c_str());
	    }
	    else
	       continue;
	 }
	 else if (End->Type == pkgCache::Dep::Conflicts ||
		  End->Type == pkgCache::Dep::Obsoletes)
	 {
	    /* Look for conflicts. Two packages that are both in the install
	       state cannot conflict so we don't check.. */
	    SPtrArray<Version *> VList = End.AllTargets();
	    for (Version **I = VList; *I != 0; I++)
	    {
	       VerIterator Ver(Cache,*I);
	       PkgIterator ConflictPkg = Ver.ParentPkg();
	       VerIterator InstallVer(Cache,Cache[ConflictPkg].InstallVer);

	       // See if the current version is conflicting
	       if (ConflictPkg.CurrentVer() == Ver && List->IsNow(ConflictPkg))
	       {
		  clog << OutputInDepth(Depth) << Pkg.FullName() << " conflicts with " << ConflictPkg.FullName() << endl;
		  /* If a loop is not present or has not yet been detected, attempt to unpack packages
		     to resolve this conflict. If there is a loop present, remove packages to resolve this conflict */
		  if (List->IsFlag(ConflictPkg,pkgOrderList::Loop) == false)
		  {
		     if (Cache[ConflictPkg].Keep() == 0 && Cache[ConflictPkg].InstallVer != 0)
		     {
			if (Debug)
			   clog << OutputInDepth(Depth) << OutputInDepth(Depth) << "Unpacking " << ConflictPkg.FullName() << " to prevent conflict" << endl;
			List->Flag(Pkg,pkgOrderList::Loop);
			if (SmartUnPack(ConflictPkg,false, Depth + 1) == true)
			   if (List->IsFlag(ConflictPkg,pkgOrderList::Loop) == false)
			      Changed = true;
			// Remove loop to allow it to be used later if needed
			List->RmFlag(Pkg,pkgOrderList::Loop);
		     }
		     else if (EarlyRemove(ConflictPkg) == false)
			return _error->Error("Internal Error, Could not early remove %s (1)",ConflictPkg.FullName().c_str());
		  }
		  else if (List->IsFlag(ConflictPkg,pkgOrderList::Removed) == false)
		  {
		     if (Debug)
			clog << OutputInDepth(Depth) << "Because of conficts knot, removing " << ConflictPkg.FullName() << " to conflict violation" << endl;
		     if (EarlyRemove(ConflictPkg) == false)
			return _error->Error("Internal Error, Could not early remove %s (2)",ConflictPkg.FullName().c_str());
		  }
	       }
	    }
	 }
	 else if (End->Type == pkgCache::Dep::DpkgBreaks)
	 {
	    SPtrArray<Version *> VList = End.AllTargets();
	    for (Version **I = VList; *I != 0; ++I)
	    {
	       VerIterator Ver(Cache,*I);
	       PkgIterator BrokenPkg = Ver.ParentPkg();
	       if (BrokenPkg.CurrentVer() != Ver)
	       {
		  if (Debug)
		     std::clog << OutputInDepth(Depth) << "  Ignore not-installed version " << Ver.VerStr() << " of " << Pkg.FullName() << " for " << End << std::endl;
		  continue;
	       }

	       // Check if it needs to be unpacked
	       if (List->IsFlag(BrokenPkg,pkgOrderList::InList) && Cache[BrokenPkg].Delete() == false &&
		   List->IsNow(BrokenPkg))
	       {
		  if (List->IsFlag(BrokenPkg,pkgOrderList::Loop) && PkgLoop)
		  {
		     // This dependancy has already been dealt with by another SmartUnPack on Pkg
		     break;
		  }
		  else
		  {
		     // Found a break, so see if we can unpack the package to avoid it
		     // but do not set loop if another SmartUnPack already deals with it
		     // Also, avoid it if the package we would unpack pre-depends on this one
		     VerIterator InstallVer(Cache,Cache[BrokenPkg].InstallVer);
		     bool circle = false;
		     for (pkgCache::DepIterator D = InstallVer.DependsList(); D.end() == false; ++D)
		     {
			if (D->Type != pkgCache::Dep::PreDepends)
			   continue;
			SPtrArray<Version *> VL = D.AllTargets();
			for (Version **I = VL; *I != 0; ++I)
			{
			   VerIterator V(Cache,*I);
			   PkgIterator P = V.ParentPkg();
			   // we are checking for installation as an easy 'protection' against or-groups and (unchosen) providers
			   if (P != Pkg || (P.CurrentVer() != V && Cache[P].InstallVer != V))
			      continue;
			   circle = true;
			   break;
			}
			if (circle == true)
			   break;
		     }
		     if (circle == true)
		     {
			if (Debug)
			   clog << OutputInDepth(Depth) << "  Avoiding " << End << " avoided as " << BrokenPkg.FullName() << " has a pre-depends on " << Pkg.FullName() << std::endl;
			continue;
		     }
		     else
		     {
			if (Debug)
			{
			   clog << OutputInDepth(Depth) << "  Unpacking " << BrokenPkg.FullName() << " to avoid " << End;
			   if (PkgLoop == true)
			      clog << " (Looping)";
			   clog << std::endl;
			}
			if (PkgLoop == false)
			   List->Flag(Pkg,pkgOrderList::Loop);
			if (SmartUnPack(BrokenPkg, false, Depth + 1) == true)
			{
			   if (List->IsFlag(BrokenPkg,pkgOrderList::Loop) == false)
			      Changed = true;
			}
			if (PkgLoop == false)
			   List->RmFlag(Pkg,pkgOrderList::Loop);
		     }
		  }
	       }
	       // Check if a package needs to be removed
	       else if (Cache[BrokenPkg].Delete() == true && List->IsFlag(BrokenPkg,pkgOrderList::Configured) == false)
	       {
		  if (Debug)
		     clog << OutputInDepth(Depth) << "  Removing " << BrokenPkg.FullName() << " to avoid " << End << endl;
		  SmartRemove(BrokenPkg);
	       }
	    }
	 }
      }
      if (i++ > max_loops)
         return _error->Error("Internal error: APT::pkgPackageManager::MaxLoopCount reached in SmartConfigure for %s, aborting", Pkg.FullName().c_str());
   } while (Changed == true);
   
   // Check for reverse conflicts.
   if (CheckRConflicts(Pkg,Pkg.RevDependsList(),
		   instVer.VerStr()) == false)
		          return false;
   
   for (PrvIterator P = instVer.ProvidesList();
	P.end() == false; ++P)
      if (Pkg->Group != P.OwnerPkg()->Group)
	 CheckRConflicts(Pkg,P.ParentPkg().RevDependsList(),P.ProvideVersion());

   if (PkgLoop)
      return true;

   List->Flag(Pkg,pkgOrderList::UnPacked,pkgOrderList::States);

   if (Immediate == true && (instVer->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
   {
      /* Do lockstep M-A:same unpacking in two phases:
	 First unpack all installed architectures, then the not installed.
	 This way we avoid that M-A: enabled packages are installed before
	 their older non-M-A enabled packages are replaced by newer versions */
      bool const installed = Pkg->CurrentVer != 0;
      if (installed == true && Install(Pkg,FileNames[Pkg->ID]) == false)
	 return false;
      for (PkgIterator P = Pkg.Group().PackageList();
	   P.end() == false; P = Pkg.Group().NextPkg(P))
      {
	 if (P->CurrentVer == 0 || P == Pkg || List->IsFlag(P,pkgOrderList::UnPacked) == true ||
	     Cache[P].InstallVer == 0 || (P.CurrentVer() == Cache[P].InstallVer &&
	      (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall))
	    continue;
	 if (SmartUnPack(P, false, Depth + 1) == false)
	    return false;
      }
      if (installed == false && Install(Pkg,FileNames[Pkg->ID]) == false)
	 return false;
      for (PkgIterator P = Pkg.Group().PackageList();
	   P.end() == false; P = Pkg.Group().NextPkg(P))
      {
	 if (P->CurrentVer != 0 || P == Pkg || List->IsFlag(P,pkgOrderList::UnPacked) == true ||
	     Cache[P].InstallVer == 0 || (P.CurrentVer() == Cache[P].InstallVer &&
	      (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall))
	    continue;
	 if (SmartUnPack(P, false, Depth + 1) == false)
	    return false;
      }
   }
   // packages which are already unpacked don't need to be unpacked again
   else if (Pkg.State() != pkgCache::PkgIterator::NeedsConfigure && Install(Pkg,FileNames[Pkg->ID]) == false)
      return false;

   if (Immediate == true) {
      // Perform immedate configuration of the package. 
         if (SmartConfigure(Pkg, Depth + 1) == false)
            _error->Warning(_("Could not perform immediate configuration on '%s'. "
               "Please see man 5 apt.conf under APT::Immediate-Configure for details. (%d)"),Pkg.FullName().c_str(),2);
   }
   
   return true;
}
									/*}}}*/
// PM::OrderInstall - Installation ordering routine			/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgPackageManager::OrderResult pkgPackageManager::OrderInstall()
{
   if (CreateOrderList() == false)
      return Failed;

   Reset();
   
   if (Debug == true)
      clog << "Beginning to order" << endl;

   bool const ordering =
	_config->FindB("PackageManager::UnpackAll",true) ?
		List->OrderUnpack(FileNames) : List->OrderCritical();
   if (ordering == false)
   {
      _error->Error("Internal ordering error");
      return Failed;
   }
   
   if (Debug == true)
      clog << "Done ordering" << endl;

   bool DoneSomething = false;
   for (pkgOrderList::iterator I = List->begin(); I != List->end(); ++I)
   {
      PkgIterator Pkg(Cache,*I);
      
      if (List->IsNow(Pkg) == false)
      {
         if (!List->IsFlag(Pkg,pkgOrderList::Configured) && !NoImmConfigure) {
            if (SmartConfigure(Pkg, 0) == false && Debug)
               _error->Warning("Internal Error, Could not configure %s",Pkg.FullName().c_str());
            // FIXME: The above warning message might need changing
         } else {
	    if (Debug == true)
	       clog << "Skipping already done " << Pkg.FullName() << endl;
	 }
	 continue;
	 
      }
      
      if (List->IsMissing(Pkg) == true)
      {
	 if (Debug == true)
	    clog << "Sequence completed at " << Pkg.FullName() << endl;
	 if (DoneSomething == false)
	 {
	    _error->Error("Internal Error, ordering was unable to handle the media swap");
	    return Failed;
	 }	 
	 return Incomplete;
      }
      
      // Sanity check
      if (Cache[Pkg].Keep() == true && 
	  Pkg.State() == pkgCache::PkgIterator::NeedsNothing &&
	  (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
      {
	 _error->Error("Internal Error, trying to manipulate a kept package (%s)",Pkg.FullName().c_str());
	 return Failed;
      }
      
      // Perform a delete or an install
      if (Cache[Pkg].Delete() == true)
      {
	 if (SmartRemove(Pkg) == false)
	    return Failed;
      }
      else
	 if (SmartUnPack(Pkg,List->IsFlag(Pkg,pkgOrderList::Immediate),0) == false)
	    return Failed;
      DoneSomething = true;
      
      if (ImmConfigureAll) {
         /* ConfigureAll here to pick up and packages left unconfigured becuase they were unpacked in the 
            "PreUnpack Checks" section */
         if (!ConfigureAll())
            return Failed; 
      }
   }

   // Final run through the configure phase
   if (ConfigureAll() == false)
      return Failed;

   // Sanity check
   for (pkgOrderList::iterator I = List->begin(); I != List->end(); ++I)
   {
      if (List->IsFlag(*I,pkgOrderList::Configured) == false)
      {
	 _error->Error("Internal error, packages left unconfigured. %s",
		       PkgIterator(Cache,*I).FullName().c_str());
	 return Failed;
      }
   }
	 
   return Completed;
}
									/*}}}*/
// PM::DoInstallPostFork - Does install part that happens after the fork /*{{{*/
// ---------------------------------------------------------------------
pkgPackageManager::OrderResult 
pkgPackageManager::DoInstallPostFork(int statusFd)
{
      if(statusFd > 0)
         // FIXME: use SetCloseExec here once it taught about throwing
	 //        exceptions instead of doing _exit(100) on failure
	 fcntl(statusFd,F_SETFD,FD_CLOEXEC); 
      bool goResult = Go(statusFd);
      if(goResult == false) 
	 return Failed;

      return Res;
};

// PM::DoInstall - Does the installation				/*{{{*/
// ---------------------------------------------------------------------
/* This uses the filenames in FileNames and the information in the
   DepCache to perform the installation of packages.*/
pkgPackageManager::OrderResult pkgPackageManager::DoInstall(int statusFd)
{
   if(DoInstallPreFork() == Failed)
      return Failed;
   
   return DoInstallPostFork(statusFd);
}
									/*}}}*/