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 #include <sstream>
  37                                                                         /*}}}*/
  38
  39 using namespace std;
  40
  41 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  42 // ---------------------------------------------------------------------
  43 /* Set the defaults for operation. The default mode with no loaded policy
  44    file matches the V0 policy engine. */
  45 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  46 {
  47    PFPriority = new signed short[Owner->Head().PackageFileCount];
  48    Pins = new Pin[Owner->Head().PackageCount];
  49
  50    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  51       Pins[I].Type = pkgVersionMatch::None;
  52
  53    // The config file has a master override.
  54    string DefRel = _config->Find("APT::Default-Release");
  55    if (DefRel.empty() == false)
  56       CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  57
  58    InitDefaults();
  59 }
  60                                                                         /*}}}*/
  61 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  62 // ---------------------------------------------------------------------
  63 /* */
  64 bool pkgPolicy::InitDefaults()
  65 {
  66    // Initialize the priorities based on the status of the package file
  67    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); I++)
  68    {
  69       PFPriority[I->ID] = 500;
  70       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  71          PFPriority[I->ID] = 100;
  72       else
  73          if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  74             PFPriority[I->ID] = 1;
  75    }
  76
  77    // Apply the defaults..
  78    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  79    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  80    signed Cur = 989;
  81    StatusOverride = false;
  82    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  83         I++, Cur--)
  84    {
  85       pkgVersionMatch Match(I->Data,I->Type);
  86       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  87       {
  88          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  89          {
  90             if (I->Priority != 0 && I->Priority > 0)
  91                Cur = I->Priority;
  92
  93             if (I->Priority < 0)
  94                PFPriority[F->ID] =  I->Priority;
  95             else
  96                PFPriority[F->ID] = Cur;
  97
  98             if (PFPriority[F->ID] > 1000)
  99                StatusOverride = true;
 100
 101             Fixed[F->ID] = true;
 102          }
 103       }
 104    }
 105
 106    if (_config->FindB("Debug::pkgPolicy",false) == true)
 107       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 108          cout << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << endl;
 109
 110    return true;
 111 }
 112                                                                         /*}}}*/
 113 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 114 // ---------------------------------------------------------------------
 115 /* Evaluate the package pins and the default list to deteremine what the
 116    best package is. */
 117 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator Pkg)
 118 {
 119    // Look for a package pin and evaluate it.
 120    signed Max = GetPriority(Pkg);
 121    pkgCache::VerIterator Pref = GetMatch(Pkg);
 122
 123    /* Falling through to the default version.. Setting Max to zero
 124       effectively excludes everything <= 0 which are the non-automatic
 125       priorities.. The status file is given a prio of 100 which will exclude
 126       not-automatic sources, except in a single shot not-installed mode.
 127       The second pseduo-status file is at prio 1000, above which will permit
 128       the user to force-downgrade things.
 129
 130       The user pin is subject to the same priority rules as default
 131       selections. Thus there are two ways to create a pin - a pin that
 132       tracks the default when the default is taken away, and a permanent
 133       pin that stays at that setting.
 134     */
 135    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 136    {
 137       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 138       {
 139          /* If this is the status file, and the current version is not the
 140             version in the status file (ie it is not installed, or somesuch)
 141             then it is not a candidate for installation, ever. This weeds
 142             out bogus entries that may be due to config-file states, or
 143             other. */
 144          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 145              Pkg.CurrentVer() != Ver)
 146             continue;
 147
 148          signed Prio = PFPriority[VF.File()->ID];
 149          if (Prio > Max)
 150          {
 151             Pref = Ver;
 152             Max = Prio;
 153          }
 154       }
 155
 156       if (Pkg.CurrentVer() == Ver && Max < 1000)
 157       {
 158          /* Elevate our current selection (or the status file itself)
 159             to the Pseudo-status priority. */
 160          if (Pref.end() == true)
 161             Pref = Ver;
 162          Max = 1000;
 163
 164          // Fast path optimize.
 165          if (StatusOverride == false)
 166             break;
 167       }
 168    }
 169    return Pref;
 170 }
 171                                                                         /*}}}*/
 172 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 173 // ---------------------------------------------------------------------
 174 /* For performance we have 3 tables, the default table, the main cache
 175    table (hashed to the cache). A blank package name indicates the pin
 176    belongs to the default table. Order of insertion matters here, the
 177    earlier defaults override later ones. */
 178 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 179                           string Data,signed short Priority)
 180 {
 181    Pin *P = 0;
 182
 183    if (Name.empty() == true)
 184       P = &*Defaults.insert(Defaults.end(),PkgPin());
 185    else
 186    {
 187       // Get a spot to put the pin
 188       pkgCache::PkgIterator Pkg = Cache->FindPkg(Name);
 189       if (Pkg.end() == true)
 190       {
 191          // Check the unmatched table
 192          for (vector<PkgPin>::iterator I = Unmatched.begin();
 193               I != Unmatched.end() && P == 0; I++)
 194             if (I->Pkg == Name)
 195                P = &*I;
 196
 197          if (P == 0)
 198             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 199       }
 200       else
 201       {
 202          P = Pins + Pkg->ID;
 203       }
 204    }
 205
 206    // Set..
 207    P->Type = Type;
 208    P->Priority = Priority;
 209    P->Data = Data;
 210 }
 211                                                                         /*}}}*/
 212 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 213 // ---------------------------------------------------------------------
 214 /* */
 215 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator Pkg)
 216 {
 217    const Pin &PPkg = Pins[Pkg->ID];
 218    if (PPkg.Type != pkgVersionMatch::None)
 219    {
 220       pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 221       return Match.Find(Pkg);
 222    }
 223    return pkgCache::VerIterator(*Pkg.Cache());
 224 }
 225                                                                         /*}}}*/
 226 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 227 // ---------------------------------------------------------------------
 228 /* */
 229 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 230 {
 231    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 232    {
 233       // In this case 0 means default priority
 234       if (Pins[Pkg->ID].Priority == 0)
 235          return 989;
 236       return Pins[Pkg->ID].Priority;
 237    }
 238
 239    return 0;
 240 }
 241                                                                         /*}}}*/
 242
 243 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 244 // ---------------------------------------------------------------------
 245 /* I'd like to see the preferences file store more than just pin information
 246    but right now that is the only stuff I have to store. Later there will
 247    have to be some kind of combined super parser to get the data into all
 248    the right classes.. */
 249 bool ReadPinFile(pkgPolicy &Plcy,string File)
 250 {
 251    if (File.empty() == true)
 252       File = _config->FindFile("Dir::Etc::Preferences");
 253
 254    if (FileExists(File) == false)
 255       return true;
 256
 257    FileFd Fd(File,FileFd::ReadOnly);
 258    pkgTagFile TF(&Fd);
 259    if (_error->PendingError() == true)
 260       return false;
 261
 262    pkgTagSection Tags;
 263    while (TF.Step(Tags) == true)
 264    {
 265       string Name = Tags.FindS("Package");
 266       if (Name.empty() == true)
 267          return _error->Error(_("Invalid record in the preferences file, no Package header"));
 268       if (Name == "*")
 269          Name = string();
 270
 271       const char *Start;
 272       const char *End;
 273       if (Tags.Find("Pin",Start,End) == false)
 274          continue;
 275
 276       const char *Word = Start;
 277       for (; Word != End && isspace(*Word) == 0; Word++);
 278
 279       // Parse the type..
 280       pkgVersionMatch::MatchType Type;
 281       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 282          Type = pkgVersionMatch::Version;
 283       else if (stringcasecmp(Start,Word,"release") == 0)
 284          Type = pkgVersionMatch::Release;
 285       else if (stringcasecmp(Start,Word,"origin") == 0)
 286          Type = pkgVersionMatch::Origin;
 287       else
 288       {
 289          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 290          continue;
 291       }
 292       for (; Word != End && isspace(*Word) != 0; Word++);
 293
 294       short int priority = Tags.FindI("Pin-Priority", 0);
 295       if (priority == 0)
 296       {
 297          _error->Warning(_("No priority (or zero) specified for pin"));
 298          continue;
 299       }
 300
 301       istringstream s(Name);
 302       string pkg;
 303       while(!s.eof())
 304       {
 305          s >> pkg;
 306          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 307       };
 308    }
 309
 310    Plcy.InitDefaults();
 311    return true;
 312 }
 313                                                                         /*}}}*/