apt-pkg/policy.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: policy.cc,v 1.10 2003/08/12 00:17:37 mdz Exp $
   4 /* ######################################################################
   5
   6    Package Version Policy implementation
   7
   8    This is just a really simple wrapper around pkgVersionMatch with
   9    some added goodies to manage the list of things..
  10
  11    Priority Table:
  12
  13    1000 -> inf = Downgradeable priorities
  14    1000        = The 'no downgrade' pseduo-status file
  15    100 -> 1000 = Standard priorities
  16    990         = Config file override package files
  17    989         = Start for preference auto-priorities
  18    500         = Default package files
  19    100         = The status file
  20    0 -> 100    = NotAutomatic sources like experimental
  21    -inf -> 0   = Never selected
  22
  23    ##################################################################### */
  24                                                                         /*}}}*/
  25 // Include Files                                                        /*{{{*/
  26 #include <apt-pkg/policy.h>
  27 #include <apt-pkg/configuration.h>
  28 #include <apt-pkg/tagfile.h>
  29 #include <apt-pkg/strutl.h>
  30 #include <apt-pkg/error.h>
  31 #include <apt-pkg/sptr.h>
  32
  33 #include <apti18n.h>
  34
  35 #include <iostream>
  36                                                                         /*}}}*/
  37
  38 using namespace std;
  39
  40 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  41 // ---------------------------------------------------------------------
  42 /* Set the defaults for operation. The default mode with no loaded policy
  43    file matches the V0 policy engine. */
  44 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  45 {
  46    PFPriority = new signed short[Owner->Head().PackageFileCount];
  47    Pins = new Pin[Owner->Head().PackageCount];
  48
  49    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  50       Pins[I].Type = pkgVersionMatch::None;
  51
  52    // The config file has a master override.
  53    string DefRel = _config->Find("APT::Default-Release");
  54    if (DefRel.empty() == false)
  55       CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  56
  57    InitDefaults();
  58 }
  59                                                                         /*}}}*/
  60 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  61 // ---------------------------------------------------------------------
  62 /* */
  63 bool pkgPolicy::InitDefaults()
  64 {
  65    // Initialize the priorities based on the status of the package file
  66    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); I++)
  67    {
  68       PFPriority[I->ID] = 500;
  69       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  70          PFPriority[I->ID] = 100;
  71       else
  72          if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  73             PFPriority[I->ID] = 1;
  74    }
  75
  76    // Apply the defaults..
  77    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  78    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  79    signed Cur = 989;
  80    StatusOverride = false;
  81    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  82         I++, Cur--)
  83    {
  84       pkgVersionMatch Match(I->Data,I->Type);
  85       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  86       {
  87          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  88          {
  89             if (I->Priority != 0 && I->Priority > 0)
  90                Cur = I->Priority;
  91
  92             if (I->Priority < 0)
  93                PFPriority[F->ID] =  I->Priority;
  94             else
  95                PFPriority[F->ID] = Cur;
  96
  97             if (PFPriority[F->ID] > 1000)
  98                StatusOverride = true;
  99
 100             Fixed[F->ID] = true;
 101          }
 102       }
 103    }
 104
 105    if (_config->FindB("Debug::pkgPolicy",false) == true)
 106       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 107          cout << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << endl;
 108
 109    return true;
 110 }
 111                                                                         /*}}}*/
 112 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 113 // ---------------------------------------------------------------------
 114 /* Evaluate the package pins and the default list to deteremine what the
 115    best package is. */
 116 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator Pkg)
 117 {
 118    // Look for a package pin and evaluate it.
 119    signed Max = GetPriority(Pkg);
 120    pkgCache::VerIterator Pref = GetMatch(Pkg);
 121
 122    /* Falling through to the default version.. Setting Max to zero
 123       effectively excludes everything <= 0 which are the non-automatic
 124       priorities.. The status file is given a prio of 100 which will exclude
 125       not-automatic sources, except in a single shot not-installed mode.
 126       The second pseduo-status file is at prio 1000, above which will permit
 127       the user to force-downgrade things.
 128
 129       The user pin is subject to the same priority rules as default
 130       selections. Thus there are two ways to create a pin - a pin that
 131       tracks the default when the default is taken away, and a permanent
 132       pin that stays at that setting.
 133     */
 134    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 135    {
 136       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 137       {
 138          /* If this is the status file, and the current version is not the
 139             version in the status file (ie it is not installed, or somesuch)
 140             then it is not a candidate for installation, ever. This weeds
 141             out bogus entries that may be due to config-file states, or
 142             other. */
 143          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 144              Pkg.CurrentVer() != Ver)
 145             continue;
 146
 147          signed Prio = PFPriority[VF.File()->ID];
 148          if (Prio > Max)
 149          {
 150             Pref = Ver;
 151             Max = Prio;
 152          }
 153       }
 154
 155       if (Pkg.CurrentVer() == Ver && Max < 1000)
 156       {
 157          /* Elevate our current selection (or the status file itself)
 158             to the Pseudo-status priority. */
 159          if (Pref.end() == true)
 160             Pref = Ver;
 161          Max = 1000;
 162
 163          // Fast path optimize.
 164          if (StatusOverride == false)
 165             break;
 166       }
 167    }
 168    return Pref;
 169 }
 170                                                                         /*}}}*/
 171 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 172 // ---------------------------------------------------------------------
 173 /* For performance we have 3 tables, the default table, the main cache
 174    table (hashed to the cache). A blank package name indicates the pin
 175    belongs to the default table. Order of insertion matters here, the
 176    earlier defaults override later ones. */
 177 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 178                           string Data,signed short Priority)
 179 {
 180    Pin *P = 0;
 181
 182    if (Name.empty() == true)
 183       P = &*Defaults.insert(Defaults.end(),PkgPin());
 184    else
 185    {
 186       // Get a spot to put the pin
 187       pkgCache::PkgIterator Pkg = Cache->FindPkg(Name);
 188       if (Pkg.end() == true)
 189       {
 190          // Check the unmatched table
 191          for (vector<PkgPin>::iterator I = Unmatched.begin();
 192               I != Unmatched.end() && P == 0; I++)
 193             if (I->Pkg == Name)
 194                P = &*I;
 195
 196          if (P == 0)
 197             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 198       }
 199       else
 200       {
 201          P = Pins + Pkg->ID;
 202       }
 203    }
 204
 205    // Set..
 206    P->Type = Type;
 207    P->Priority = Priority;
 208    P->Data = Data;
 209 }
 210                                                                         /*}}}*/
 211 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 212 // ---------------------------------------------------------------------
 213 /* */
 214 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator Pkg)
 215 {
 216    const Pin &PPkg = Pins[Pkg->ID];
 217    if (PPkg.Type != pkgVersionMatch::None)
 218    {
 219       pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 220       return Match.Find(Pkg);
 221    }
 222    return pkgCache::VerIterator(*Pkg.Cache());
 223 }
 224                                                                         /*}}}*/
 225 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 226 // ---------------------------------------------------------------------
 227 /* */
 228 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 229 {
 230    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 231    {
 232       // In this case 0 means default priority
 233       if (Pins[Pkg->ID].Priority == 0)
 234          return 989;
 235       return Pins[Pkg->ID].Priority;
 236    }
 237
 238    return 0;
 239 }
 240                                                                         /*}}}*/
 241
 242 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 243 // ---------------------------------------------------------------------
 244 /* I'd like to see the preferences file store more than just pin information
 245    but right now that is the only stuff I have to store. Later there will
 246    have to be some kind of combined super parser to get the data into all
 247    the right classes.. */
 248 bool ReadPinFile(pkgPolicy &Plcy,string File)
 249 {
 250    if (File.empty() == true)
 251       File = _config->FindFile("Dir::Etc::Preferences");
 252
 253    if (FileExists(File) == false)
 254       return true;
 255
 256    FileFd Fd(File,FileFd::ReadOnly);
 257    pkgTagFile TF(&Fd);
 258    if (_error->PendingError() == true)
 259       return false;
 260
 261    pkgTagSection Tags;
 262    while (TF.Step(Tags) == true)
 263    {
 264       string Name = Tags.FindS("Package");
 265       if (Name.empty() == true)
 266          return _error->Error(_("Invalid record in the preferences file, no Package header"));
 267       if (Name == "*")
 268          Name = string();
 269
 270       const char *Start;
 271       const char *End;
 272       if (Tags.Find("Pin",Start,End) == false)
 273          continue;
 274
 275       const char *Word = Start;
 276       for (; Word != End && isspace(*Word) == 0; Word++);
 277
 278       // Parse the type..
 279       pkgVersionMatch::MatchType Type;
 280       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 281          Type = pkgVersionMatch::Version;
 282       else if (stringcasecmp(Start,Word,"release") == 0)
 283          Type = pkgVersionMatch::Release;
 284       else if (stringcasecmp(Start,Word,"origin") == 0)
 285          Type = pkgVersionMatch::Origin;
 286       else
 287       {
 288          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 289          continue;
 290       }
 291       for (; Word != End && isspace(*Word) != 0; Word++);
 292
 293       short int priority = Tags.FindI("Pin-Priority", 0);
 294       if (priority == 0)
 295       {
 296          _error->Warning(_("No priority (or zero) specified for pin"));
 297          continue;
 298       }
 299
 300       Plcy.CreatePin(Type,Name,string(Word,End),priority);
 301    }
 302
 303    Plcy.InitDefaults();
 304    return true;
 305 }
 306                                                                         /*}}}*/