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 #ifdef __GNUG__
  27 #pragma implementation "apt-pkg/policy.h"
  28 #endif
  29 #include <apt-pkg/policy.h>
  30 #include <apt-pkg/configuration.h>
  31 #include <apt-pkg/tagfile.h>
  32 #include <apt-pkg/strutl.h>
  33 #include <apt-pkg/error.h>
  34 #include <apt-pkg/sptr.h>
  35
  36 #include <apti18n.h>
  37
  38 #include <iostream>
  39                                                                         /*}}}*/
  40
  41 using namespace std;
  42
  43 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  44 // ---------------------------------------------------------------------
  45 /* Set the defaults for operation. The default mode with no loaded policy
  46    file matches the V0 policy engine. */
  47 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  48 {
  49    PFPriority = new signed short[Owner->Head().PackageFileCount];
  50    Pins = new Pin[Owner->Head().PackageCount];
  51
  52    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  53       Pins[I].Type = pkgVersionMatch::None;
  54
  55    // The config file has a master override.
  56    string DefRel = _config->Find("APT::Default-Release");
  57    if (DefRel.empty() == false)
  58       CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  59
  60    InitDefaults();
  61 }
  62                                                                         /*}}}*/
  63 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  64 // ---------------------------------------------------------------------
  65 /* */
  66 bool pkgPolicy::InitDefaults()
  67 {
  68    // Initialize the priorities based on the status of the package file
  69    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); I++)
  70    {
  71       PFPriority[I->ID] = 500;
  72       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  73          PFPriority[I->ID] = 100;
  74       else
  75          if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  76             PFPriority[I->ID] = 1;
  77    }
  78
  79    // Apply the defaults..
  80    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  81    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  82    signed Cur = 989;
  83    StatusOverride = false;
  84    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  85         I++, Cur--)
  86    {
  87       pkgVersionMatch Match(I->Data,I->Type);
  88       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  89       {
  90          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  91          {
  92             if (I->Priority != 0 && I->Priority > 0)
  93                Cur = I->Priority;
  94
  95             if (I->Priority < 0)
  96                PFPriority[F->ID] =  I->Priority;
  97             else
  98                PFPriority[F->ID] = Cur;
  99
 100             if (PFPriority[F->ID] > 1000)
 101                StatusOverride = true;
 102
 103             Fixed[F->ID] = true;
 104          }
 105       }
 106    }
 107
 108    if (_config->FindB("Debug::pkgPolicy",false) == true)
 109       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 110          cout << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << endl;
 111
 112    return true;
 113 }
 114                                                                         /*}}}*/
 115 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 116 // ---------------------------------------------------------------------
 117 /* Evaluate the package pins and the default list to deteremine what the
 118    best package is. */
 119 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator Pkg)
 120 {
 121    // Look for a package pin and evaluate it.
 122    signed Max = GetPriority(Pkg);
 123    pkgCache::VerIterator Pref = GetMatch(Pkg);
 124
 125    /* Falling through to the default version.. Setting Max to zero
 126       effectively excludes everything <= 0 which are the non-automatic
 127       priorities.. The status file is given a prio of 100 which will exclude
 128       not-automatic sources, except in a single shot not-installed mode.
 129       The second pseduo-status file is at prio 1000, above which will permit
 130       the user to force-downgrade things.
 131
 132       The user pin is subject to the same priority rules as default
 133       selections. Thus there are two ways to create a pin - a pin that
 134       tracks the default when the default is taken away, and a permanent
 135       pin that stays at that setting.
 136     */
 137    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 138    {
 139       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 140       {
 141          /* If this is the status file, and the current version is not the
 142             version in the status file (ie it is not installed, or somesuch)
 143             then it is not a candidate for installation, ever. This weeds
 144             out bogus entries that may be due to config-file states, or
 145             other. */
 146          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 147              Pkg.CurrentVer() != Ver)
 148             continue;
 149
 150          signed Prio = PFPriority[VF.File()->ID];
 151          if (Prio > Max)
 152          {
 153             Pref = Ver;
 154             Max = Prio;
 155          }
 156       }
 157
 158       if (Pkg.CurrentVer() == Ver && Max < 1000)
 159       {
 160          /* Elevate our current selection (or the status file itself)
 161             to the Pseudo-status priority. */
 162          if (Pref.end() == true)
 163             Pref = Ver;
 164          Max = 1000;
 165
 166          // Fast path optimize.
 167          if (StatusOverride == false)
 168             break;
 169       }
 170    }
 171    return Pref;
 172 }
 173                                                                         /*}}}*/
 174 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 175 // ---------------------------------------------------------------------
 176 /* For performance we have 3 tables, the default table, the main cache
 177    table (hashed to the cache). A blank package name indicates the pin
 178    belongs to the default table. Order of insertion matters here, the
 179    earlier defaults override later ones. */
 180 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 181                           string Data,signed short Priority)
 182 {
 183    Pin *P = 0;
 184
 185    if (Name.empty() == true)
 186       P = &*Defaults.insert(Defaults.end(),PkgPin());
 187    else
 188    {
 189       // Get a spot to put the pin
 190       pkgCache::PkgIterator Pkg = Cache->FindPkg(Name);
 191       if (Pkg.end() == true)
 192       {
 193          // Check the unmatched table
 194          for (vector<PkgPin>::iterator I = Unmatched.begin();
 195               I != Unmatched.end() && P == 0; I++)
 196             if (I->Pkg == Name)
 197                P = &*I;
 198
 199          if (P == 0)
 200             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 201       }
 202       else
 203       {
 204          P = Pins + Pkg->ID;
 205       }
 206    }
 207
 208    // Set..
 209    P->Type = Type;
 210    P->Priority = Priority;
 211    P->Data = Data;
 212 }
 213                                                                         /*}}}*/
 214 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 215 // ---------------------------------------------------------------------
 216 /* */
 217 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator Pkg)
 218 {
 219    const Pin &PPkg = Pins[Pkg->ID];
 220    if (PPkg.Type != pkgVersionMatch::None)
 221    {
 222       pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 223       return Match.Find(Pkg);
 224    }
 225    return pkgCache::VerIterator(*Pkg.Cache());
 226 }
 227                                                                         /*}}}*/
 228 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 229 // ---------------------------------------------------------------------
 230 /* */
 231 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 232 {
 233    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 234    {
 235       // In this case 0 means default priority
 236       if (Pins[Pkg->ID].Priority == 0)
 237          return 989;
 238       return Pins[Pkg->ID].Priority;
 239    }
 240
 241    return 0;
 242 }
 243                                                                         /*}}}*/
 244
 245 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 246 // ---------------------------------------------------------------------
 247 /* I'd like to see the preferences file store more than just pin information
 248    but right now that is the only stuff I have to store. Later there will
 249    have to be some kind of combined super parser to get the data into all
 250    the right classes.. */
 251 bool ReadPinFile(pkgPolicy &Plcy,string File)
 252 {
 253    if (File.empty() == true)
 254       File = _config->FindFile("Dir::Etc::Preferences");
 255
 256    if (FileExists(File) == false)
 257       return true;
 258
 259    FileFd Fd(File,FileFd::ReadOnly);
 260    pkgTagFile TF(&Fd);
 261    if (_error->PendingError() == true)
 262       return false;
 263
 264    pkgTagSection Tags;
 265    while (TF.Step(Tags) == true)
 266    {
 267       string Name = Tags.FindS("Package");
 268       if (Name.empty() == true)
 269          return _error->Error(_("Invalid record in the preferences file, no Package header"));
 270       if (Name == "*")
 271          Name = string();
 272
 273       const char *Start;
 274       const char *End;
 275       if (Tags.Find("Pin",Start,End) == false)
 276          continue;
 277
 278       const char *Word = Start;
 279       for (; Word != End && isspace(*Word) == 0; Word++);
 280
 281       // Parse the type..
 282       pkgVersionMatch::MatchType Type;
 283       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 284          Type = pkgVersionMatch::Version;
 285       else if (stringcasecmp(Start,Word,"release") == 0)
 286          Type = pkgVersionMatch::Release;
 287       else if (stringcasecmp(Start,Word,"origin") == 0)
 288          Type = pkgVersionMatch::Origin;
 289       else
 290       {
 291          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 292          continue;
 293       }
 294       for (; Word != End && isspace(*Word) != 0; Word++);
 295
 296       short int priority = Tags.FindI("Pin-Priority", 0);
 297       if (priority == 0)
 298       {
 299          _error->Warning(_("No priority (or zero) specified for pin"));
 300          continue;
 301       }
 302
 303       Plcy.CreatePin(Type,Name,string(Word,End),priority);
 304    }
 305
 306    Plcy.InitDefaults();
 307    return true;
 308 }
 309                                                                         /*}}}*/