apt/apt-pkg/algorithms.cc

// -*- mode: cpp; mode: fold -*-
// Description								/*{{{*/
// $Id: algorithms.cc,v 1.44 2002/11/28 18:49:16 jgg Exp $
/* ######################################################################

   Algorithms - A set of misc algorithms

   The pkgProblemResolver class has become insanely complex and
   very sophisticated, it handles every test case I have thrown at it
   to my satisfaction. Understanding exactly why all the steps the class
   does are required is difficult and changing though not very risky
   may result in other cases not working.
   
   ##################################################################### */
									/*}}}*/
// Include Files							/*{{{*/
#include <apt-pkg/algorithms.h>
#include <apt-pkg/error.h>
#include <apt-pkg/configuration.h>
#include <apt-pkg/version.h>
#include <apt-pkg/sptr.h>
#include <apt-pkg/acquire-item.h>
    
#include <apti18n.h>
#include <sys/types.h>
#include <cstdlib>
#include <algorithm>
#include <iostream>
									/*}}}*/
using namespace std;

pkgProblemResolver *pkgProblemResolver::This = 0;

// Simulate::Simulate - Constructor					/*{{{*/
// ---------------------------------------------------------------------
/* The legacy translations here of input Pkg iterators is obsolete, 
   this is not necessary since the pkgCaches are fully shared now. */
pkgSimulate::pkgSimulate(pkgDepCache *Cache) : pkgPackageManager(Cache),
		            iPolicy(Cache),
			    Sim(&Cache->GetCache(),&iPolicy),
			    group(Sim)
{
   Sim.Init(0);
   Flags = new unsigned char[Cache->Head().PackageCount];
   memset(Flags,0,sizeof(*Flags)*Cache->Head().PackageCount);

   // Fake a filename so as not to activate the media swapping
   string Jnk = "SIMULATE";
   for (unsigned int I = 0; I != Cache->Head().PackageCount; I++)
      FileNames[I] = Jnk;
}
									/*}}}*/
// Simulate::Describe - Describe a package				/*{{{*/
// ---------------------------------------------------------------------
/* Parameter Current == true displays the current package version,
   Parameter Candidate == true displays the candidate package version */
void pkgSimulate::Describe(PkgIterator Pkg,ostream &out,bool Current,bool Candidate)
{
   VerIterator Ver(Sim);
 
   out << Pkg.Name();

   if (Current == true)
   {
      Ver = Pkg.CurrentVer();
      if (Ver.end() == false)
         out << " [" << Ver.VerStr() << ']';
   }

   if (Candidate == true)
   {
      Ver = Sim[Pkg].CandidateVerIter(Sim);
      if (Ver.end() == true)
         return;
   
      out << " (" << Ver.VerStr() << ' ' << Ver.RelStr() << ')';
   }
}
									/*}}}*/
// Simulate::Install - Simulate unpacking of a package			/*{{{*/
// ---------------------------------------------------------------------
/* */
bool pkgSimulate::Install(PkgIterator iPkg,string /*File*/)
{
   // Adapt the iterator
   PkgIterator Pkg = Sim.FindPkg(iPkg.Name(), iPkg.Arch());
   Flags[Pkg->ID] = 1;
   
   cout << "Inst ";
   Describe(Pkg,cout,true,true);
   Sim.MarkInstall(Pkg,false);

   if (strcmp(Pkg.Arch(),"all") == 0)
   {
      pkgCache::GrpIterator G = Pkg.Group();
      pkgCache::GrpIterator iG = iPkg.Group();
      for (pkgCache::PkgIterator P = G.FindPkg("any"); P.end() != true; P = G.NextPkg(P))
      {
	 if (strcmp(P.Arch(), "all") == 0)
	    continue;
	 if (iG.FindPkg(P.Arch())->CurrentVer == 0)
	    continue;
	 Flags[P->ID] = 1;
	 Sim.MarkInstall(P, false);
      }
   }

   // Look for broken conflicts+predepends.
   for (PkgIterator I = Sim.PkgBegin(); I.end() == false; I++)
   {
      if (Sim[I].InstallVer == 0)
	 continue;
      
      for (DepIterator D = Sim[I].InstVerIter(Sim).DependsList(); D.end() == false;)
      {
	 DepIterator Start;
	 DepIterator End;
	 D.GlobOr(Start,End);
	 if (Start->Type == pkgCache::Dep::Conflicts ||
	     Start->Type == pkgCache::Dep::DpkgBreaks ||
	     Start->Type == pkgCache::Dep::Obsoletes ||
	     End->Type == pkgCache::Dep::PreDepends)
         {
	    if ((Sim[End] & pkgDepCache::DepGInstall) == 0)
	    {
	       cout << " [" << I.Name() << " on " << Start.TargetPkg().Name() << ']';
	       if (Start->Type == pkgCache::Dep::Conflicts)
		  _error->Error("Fatal, conflicts violated %s",I.Name());
	    }	    
	 }
      }      
   }

   if (Sim.BrokenCount() != 0)
      ShortBreaks();
   else
      cout << endl;
   return true;
}
									/*}}}*/
// Simulate::Configure - Simulate configuration of a Package		/*{{{*/
// ---------------------------------------------------------------------
/* This is not an acurate simulation of relatity, we should really not
   install the package.. For some investigations it may be necessary 
   however. */
bool pkgSimulate::Configure(PkgIterator iPkg)
{
   // Adapt the iterator
   PkgIterator Pkg = Sim.FindPkg(iPkg.Name(), iPkg.Arch());
   
   Flags[Pkg->ID] = 2;

   if (strcmp(Pkg.Arch(),"all") == 0)
   {
      pkgCache::GrpIterator G = Pkg.Group();
      for (pkgCache::PkgIterator P = G.FindPkg("any"); P.end() != true; P = G.NextPkg(P))
      {
	 if (strcmp(P.Arch(), "all") == 0)
	    continue;
	 if (Flags[P->ID] == 1)
	    Flags[P->ID] = 2;
      }
   }

//   Sim.MarkInstall(Pkg,false);
   if (Sim[Pkg].InstBroken() == true)
   {
      cout << "Conf " << Pkg.Name() << " broken" << endl;

      Sim.Update();
      
      // Print out each package and the failed dependencies
      for (pkgCache::DepIterator D = Sim[Pkg].InstVerIter(Sim).DependsList(); D.end() == false; D++)
      {
	 if (Sim.IsImportantDep(D) == false || 
	     (Sim[D] & pkgDepCache::DepInstall) != 0)
	    continue;
	 
	 if (D->Type == pkgCache::Dep::Obsoletes)
	    cout << " Obsoletes:" << D.TargetPkg().Name();
	 else if (D->Type == pkgCache::Dep::Conflicts)
	    cout << " Conflicts:" << D.TargetPkg().Name();
	 else if (D->Type == pkgCache::Dep::DpkgBreaks)
	    cout << " Breaks:" << D.TargetPkg().Name();
	 else
	    cout << " Depends:" << D.TargetPkg().Name();
      }	    
      cout << endl;

      _error->Error("Conf Broken %s",Pkg.Name());
   }   
   else
   {
      cout << "Conf "; 
      Describe(Pkg,cout,false,true);
   }

   if (Sim.BrokenCount() != 0)
      ShortBreaks();
   else
      cout << endl;
   
   return true;
}
									/*}}}*/
// Simulate::Remove - Simulate the removal of a package			/*{{{*/
// ---------------------------------------------------------------------
/* */
bool pkgSimulate::Remove(PkgIterator iPkg,bool Purge)
{
   // Adapt the iterator
   PkgIterator Pkg = Sim.FindPkg(iPkg.Name(), iPkg.Arch());

   Flags[Pkg->ID] = 3;
   Sim.MarkDelete(Pkg);

   if (strcmp(Pkg.Arch(),"all") == 0)
   {
      pkgCache::GrpIterator G = Pkg.Group();
      pkgCache::GrpIterator iG = iPkg.Group();
      for (pkgCache::PkgIterator P = G.FindPkg("any"); P.end() != true; P = G.NextPkg(P))
      {
	 if (strcmp(P.Arch(), "all") == 0)
	    continue;
	 if (iG.FindPkg(P.Arch())->CurrentVer == 0)
	    continue;
	 Flags[P->ID] = 3;
	 Sim.MarkDelete(P);
      }
   }

   if (Purge == true)
      cout << "Purg ";
   else
      cout << "Remv ";
   Describe(Pkg,cout,true,false);

   if (Sim.BrokenCount() != 0)
      ShortBreaks();
   else
      cout << endl;

   return true;
}
									/*}}}*/
// Simulate::ShortBreaks - Print out a short line describing all breaks	/*{{{*/
// ---------------------------------------------------------------------
/* */
void pkgSimulate::ShortBreaks()
{
   cout << " [";
   for (PkgIterator I = Sim.PkgBegin(); I.end() == false; I++)
   {
      if (Sim[I].InstBroken() == true)
      {
	 if (Flags[I->ID] == 0)
	    cout << I.Name() << ' ';
/*	 else
	    cout << I.Name() << "! ";*/
      }      
   }
   cout << ']' << endl;
}
									/*}}}*/
// ApplyStatus - Adjust for non-ok packages				/*{{{*/
// ---------------------------------------------------------------------
/* We attempt to change the state of the all packages that have failed
   installation toward their real state. The ordering code will perform 
   the necessary calculations to deal with the problems. */
bool pkgApplyStatus(pkgDepCache &Cache)
{
   pkgDepCache::ActionGroup group(Cache);

   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
   {
      if (I->VersionList == 0)
	 continue;
	 
      // Only choice for a ReInstReq package is to reinstall
      if (I->InstState == pkgCache::State::ReInstReq ||
	  I->InstState == pkgCache::State::HoldReInstReq)
      {
	 if (I->CurrentVer != 0 && I.CurrentVer().Downloadable() == true)
	    Cache.MarkKeep(I, false, false);
	 else
	 {
	    // Is this right? Will dpkg choke on an upgrade?
	    if (Cache[I].CandidateVer != 0 &&
		 Cache[I].CandidateVerIter(Cache).Downloadable() == true)
	       Cache.MarkInstall(I, false, 0, false);
	    else
	       return _error->Error(_("The package %s needs to be reinstalled, "
				    "but I can't find an archive for it."),I.Name());
	 }
	 
	 continue;
      }
      
      switch (I->CurrentState)
      {
	 /* This means installation failed somehow - it does not need to be
	    re-unpacked (probably) */
	 case pkgCache::State::UnPacked:
	 case pkgCache::State::HalfConfigured:
	 case pkgCache::State::TriggersAwaited:
	 case pkgCache::State::TriggersPending:
	 if ((I->CurrentVer != 0 && I.CurrentVer().Downloadable() == true) ||
	     I.State() != pkgCache::PkgIterator::NeedsUnpack)
	    Cache.MarkKeep(I, false, false);
	 else
	 {
	    if (Cache[I].CandidateVer != 0 &&
		 Cache[I].CandidateVerIter(Cache).Downloadable() == true)
	       Cache.MarkInstall(I, true, 0, false);
	    else
	       Cache.MarkDelete(I);
	 }
	 break;

	 // This means removal failed
	 case pkgCache::State::HalfInstalled:
	 Cache.MarkDelete(I);
	 break;
	 
	 default:
	 if (I->InstState != pkgCache::State::Ok)
	    return _error->Error("The package %s is not ok and I "
				 "don't know how to fix it!",I.Name());
      }
   }
   return true;
}
									/*}}}*/
// FixBroken - Fix broken packages					/*{{{*/
// ---------------------------------------------------------------------
/* This autoinstalls every broken package and then runs the problem resolver
   on the result. */
bool pkgFixBroken(pkgDepCache &Cache)
{
   pkgDepCache::ActionGroup group(Cache);

   // Auto upgrade all broken packages
   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
      if (Cache[I].NowBroken() == true)
	 Cache.MarkInstall(I, true, 0, false);
   
   /* Fix packages that are in a NeedArchive state but don't have a
      downloadable install version */
   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
   {
      if (I.State() != pkgCache::PkgIterator::NeedsUnpack ||
	  Cache[I].Delete() == true)
	 continue;
      
      if (Cache[I].InstVerIter(Cache).Downloadable() == false)
	 continue;

      Cache.MarkInstall(I, true, 0, false);
   }
   
   pkgProblemResolver Fix(&Cache);
   return Fix.Resolve(true);
}
									/*}}}*/
// DistUpgrade - Distribution upgrade					/*{{{*/
// ---------------------------------------------------------------------
/* This autoinstalls every package and then force installs every 
   pre-existing package. This creates the initial set of conditions which 
   most likely contain problems because too many things were installed.
   
   The problem resolver is used to resolve the problems.
 */
bool pkgDistUpgrade(pkgDepCache &Cache)
{
   pkgDepCache::ActionGroup group(Cache);

   /* Auto upgrade all installed packages, this provides the basis 
      for the installation */
   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
      if (I->CurrentVer != 0)
	 Cache.MarkInstall(I, true, 0, false);

   /* Now, auto upgrade all essential packages - this ensures that
      the essential packages are present and working */
   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
      if ((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
	 Cache.MarkInstall(I, true, 0, false);
   
   /* We do it again over all previously installed packages to force 
      conflict resolution on them all. */
   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
      if (I->CurrentVer != 0)
	 Cache.MarkInstall(I, false, 0, false);

   pkgProblemResolver Fix(&Cache);

   // Hold back held packages.
   if (_config->FindB("APT::Ignore-Hold",false) == false)
   {
      for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
      {
	 if (I->SelectedState == pkgCache::State::Hold)
	 {
	    Fix.Protect(I);
	    Cache.MarkKeep(I, false, false);
	 }
      }
   }
   
   return Fix.Resolve();
}
									/*}}}*/
// AllUpgrade - Upgrade as many packages as possible			/*{{{*/
// ---------------------------------------------------------------------
/* Right now the system must be consistent before this can be called.
   It also will not change packages marked for install, it only tries
   to install packages not marked for install */
bool pkgAllUpgrade(pkgDepCache &Cache)
{
   pkgDepCache::ActionGroup group(Cache);

   pkgProblemResolver Fix(&Cache);

   if (Cache.BrokenCount() != 0)
      return false;
   
   // Upgrade all installed packages
   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
   {
      if (Cache[I].Install() == true)
	 Fix.Protect(I);
	  
      if (_config->FindB("APT::Ignore-Hold",false) == false)
	 if (I->SelectedState == pkgCache::State::Hold)
	    continue;
      
      if (I->CurrentVer != 0 && Cache[I].InstallVer != 0)
	 Cache.MarkInstall(I, false, 0, false);
   }
      
   return Fix.ResolveByKeep();
}
									/*}}}*/
// MinimizeUpgrade - Minimizes the set of packages to be upgraded	/*{{{*/
// ---------------------------------------------------------------------
/* This simply goes over the entire set of packages and tries to keep 
   each package marked for upgrade. If a conflict is generated then 
   the package is restored. */
bool pkgMinimizeUpgrade(pkgDepCache &Cache)
{   
   pkgDepCache::ActionGroup group(Cache);

   if (Cache.BrokenCount() != 0)
      return false;
   
   // We loop for 10 tries to get the minimal set size.
   bool Change = false;
   unsigned int Count = 0;
   do
   {
      Change = false;
      for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
      {
	 // Not interesting
	 if (Cache[I].Upgrade() == false || Cache[I].NewInstall() == true)
	    continue;

	 // Keep it and see if that is OK
	 Cache.MarkKeep(I, false, false);
	 if (Cache.BrokenCount() != 0)
	    Cache.MarkInstall(I, false, 0, false);
	 else
	 {
	    // If keep didnt actually do anything then there was no change..
	    if (Cache[I].Upgrade() == false)
	       Change = true;
	 }	 
      }      
      Count++;
   }
   while (Change == true && Count < 10);

   if (Cache.BrokenCount() != 0)
      return _error->Error("Internal Error in pkgMinimizeUpgrade");
   
   return true;
}
									/*}}}*/
// ProblemResolver::pkgProblemResolver - Constructor			/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgProblemResolver::pkgProblemResolver(pkgDepCache *pCache) : Cache(*pCache)
{
   // Allocate memory
   unsigned long Size = Cache.Head().PackageCount;
   Scores = new signed short[Size];
   Flags = new unsigned char[Size];
   memset(Flags,0,sizeof(*Flags)*Size);
   
   // Set debug to true to see its decision logic
   Debug = _config->FindB("Debug::pkgProblemResolver",false);
}
									/*}}}*/
// ProblemResolver::~pkgProblemResolver - Destructor			/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgProblemResolver::~pkgProblemResolver()
{
   delete [] Scores;
   delete [] Flags;
}
									/*}}}*/
// ProblemResolver::ScoreSort - Sort the list by score			/*{{{*/
// ---------------------------------------------------------------------
/* */
int pkgProblemResolver::ScoreSort(const void *a,const void *b)
{
   Package const **A = (Package const **)a;
   Package const **B = (Package const **)b;
   if (This->Scores[(*A)->ID] > This->Scores[(*B)->ID])
      return -1;
   if (This->Scores[(*A)->ID] < This->Scores[(*B)->ID])
      return 1;
   return 0;
}
									/*}}}*/
// ProblemResolver::MakeScores - Make the score table			/*{{{*/
// ---------------------------------------------------------------------
/* */
void pkgProblemResolver::MakeScores()
{
   unsigned long Size = Cache.Head().PackageCount;
   memset(Scores,0,sizeof(*Scores)*Size);

   // Important Required Standard Optional Extra
   signed short PrioMap[] = {
      0,
      (signed short) _config->FindI("pkgProblemResolver::Scores::Important",3),
      (signed short) _config->FindI("pkgProblemResolver::Scores::Required",2),
      (signed short) _config->FindI("pkgProblemResolver::Scores::Standard",1),
      (signed short) _config->FindI("pkgProblemResolver::Scores::Optional",-1),
      (signed short) _config->FindI("pkgProblemResolver::Scores::Extra",-2)
   };
   signed short PrioEssentials = _config->FindI("pkgProblemResolver::Scores::Essentials",100);
   signed short PrioInstalledAndNotObsolete = _config->FindI("pkgProblemResolver::Scores::NotObsolete",1);
   signed short PrioDepends = _config->FindI("pkgProblemResolver::Scores::Depends",1);
   signed short PrioRecommends = _config->FindI("pkgProblemResolver::Scores::Recommends",1);
   signed short AddProtected = _config->FindI("pkgProblemResolver::Scores::AddProtected",10000);
   signed short AddEssential = _config->FindI("pkgProblemResolver::Scores::AddEssential",5000);

   if (_config->FindB("Debug::pkgProblemResolver::ShowScores",false) == true)
      clog << "Settings used to calculate pkgProblemResolver::Scores::" << endl
         << "  Important => " << PrioMap[1] << endl
         << "  Required => " << PrioMap[2] << endl
         << "  Standard => " << PrioMap[3] << endl
         << "  Optional => " << PrioMap[4] << endl
         << "  Extra => " << PrioMap[5] << endl
         << "  Essentials => " << PrioEssentials << endl
         << "  InstalledAndNotObsolete => " << PrioInstalledAndNotObsolete << endl
         << "  Depends => " << PrioDepends << endl
         << "  Recommends => " << PrioRecommends << endl
         << "  AddProtected => " << AddProtected << endl
         << "  AddEssential => " << AddEssential << endl;

   // Generate the base scores for a package based on its properties
   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
   {
      if (Cache[I].InstallVer == 0)
	 continue;
      
      signed short &Score = Scores[I->ID];
      
      /* This is arbitrary, it should be high enough to elevate an
         essantial package above most other packages but low enough
	 to allow an obsolete essential packages to be removed by
	 a conflicts on a powerfull normal package (ie libc6) */
      if ((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
	 Score += PrioEssentials;

      // We transform the priority
      if (Cache[I].InstVerIter(Cache)->Priority <= 5)
	 Score += PrioMap[Cache[I].InstVerIter(Cache)->Priority];
      
      /* This helps to fix oddball problems with conflicting packages
         on the same level. We enhance the score of installed packages 
	 if those are not obsolete
      */
      if (I->CurrentVer != 0 && Cache[I].CandidateVer != 0 && Cache[I].CandidateVerIter(Cache).Downloadable())
	 Score += PrioInstalledAndNotObsolete;
   }

   // Now that we have the base scores we go and propogate dependencies
   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; I++)
   {