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 and ButAutomaticUpgrades sources
  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/fileutl.h>
  31 #include <apt-pkg/error.h>
  32 #include <apt-pkg/sptr.h>
  33
  34 #include <apti18n.h>
  35
  36 #include <iostream>
  37 #include <sstream>
  38                                                                         /*}}}*/
  39
  40 using namespace std;
  41
  42 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  43 // ---------------------------------------------------------------------
  44 /* Set the defaults for operation. The default mode with no loaded policy
  45    file matches the V0 policy engine. */
  46 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  47 {
  48    if (Owner == 0 || &(Owner->Head()) == 0)
  49       return;
  50    PFPriority = new signed short[Owner->Head().PackageFileCount];
  51    Pins = new Pin[Owner->Head().PackageCount];
  52
  53    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  54       Pins[I].Type = pkgVersionMatch::None;
  55
  56    // The config file has a master override.
  57    string DefRel = _config->Find("APT::Default-Release");
  58    if (DefRel.empty() == false)
  59       CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  60
  61    InitDefaults();
  62 }
  63                                                                         /*}}}*/
  64 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  65 // ---------------------------------------------------------------------
  66 /* */
  67 bool pkgPolicy::InitDefaults()
  68 {
  69    // Initialize the priorities based on the status of the package file
  70    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); I++)
  71    {
  72       PFPriority[I->ID] = 500;
  73       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  74          PFPriority[I->ID] = 100;
  75       else if ((I->Flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
  76          PFPriority[I->ID] = 100;
  77       else if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  78          PFPriority[I->ID] = 1;
  79    }
  80
  81    // Apply the defaults..
  82    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  83    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  84    signed Cur = 989;
  85    StatusOverride = false;
  86    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  87         I++, Cur--)
  88    {
  89       pkgVersionMatch Match(I->Data,I->Type);
  90       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  91       {
  92          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  93          {
  94             if (I->Priority != 0 && I->Priority > 0)
  95                Cur = I->Priority;
  96
  97             if (I->Priority < 0)
  98                PFPriority[F->ID] =  I->Priority;
  99             else
 100                PFPriority[F->ID] = Cur;
 101
 102             if (PFPriority[F->ID] > 1000)
 103                StatusOverride = true;
 104
 105             Fixed[F->ID] = true;
 106          }
 107       }
 108    }
 109
 110    if (_config->FindB("Debug::pkgPolicy",false) == true)
 111       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 112          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 113
 114    return true;
 115 }
 116                                                                         /*}}}*/
 117 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 118 // ---------------------------------------------------------------------
 119 /* Evaluate the package pins and the default list to deteremine what the
 120    best package is. */
 121 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 122 {
 123    // Look for a package pin and evaluate it.
 124    signed Max = GetPriority(Pkg);
 125    pkgCache::VerIterator Pref = GetMatch(Pkg);
 126
 127    // Alternatives in case we can not find our package pin (Bug#512318).
 128    signed MaxAlt = 0;
 129    pkgCache::VerIterator PrefAlt;
 130
 131    // no package = no candidate version
 132    if (Pkg.end() == true)
 133       return Pref;
 134
 135    // packages with a pin lower than 0 have no newer candidate than the current version
 136    if (Max < 0)
 137       return Pkg.CurrentVer();
 138
 139    /* Falling through to the default version.. Setting Max to zero
 140       effectively excludes everything <= 0 which are the non-automatic
 141       priorities.. The status file is given a prio of 100 which will exclude
 142       not-automatic sources, except in a single shot not-installed mode.
 143       The second pseduo-status file is at prio 1000, above which will permit
 144       the user to force-downgrade things.
 145
 146       The user pin is subject to the same priority rules as default
 147       selections. Thus there are two ways to create a pin - a pin that
 148       tracks the default when the default is taken away, and a permanent
 149       pin that stays at that setting.
 150     */
 151    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 152    {
 153       /* Lets see if this version is the installed version */
 154       bool instVer = (Pkg.CurrentVer() == Ver);
 155       if (Ver.Pseudo() == true && instVer == false)
 156       {
 157          pkgCache::PkgIterator const allPkg = Ver.ParentPkg().Group().FindPkg("all");
 158          if (allPkg->CurrentVer != 0 && allPkg.CurrentVer()->Hash == Ver->Hash &&
 159              strcmp(allPkg.CurVersion(), Ver.VerStr()) == 0)
 160             instVer = true;
 161       }
 162
 163       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 164       {
 165          /* If this is the status file, and the current version is not the
 166             version in the status file (ie it is not installed, or somesuch)
 167             then it is not a candidate for installation, ever. This weeds
 168             out bogus entries that may be due to config-file states, or
 169             other. */
 170          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 171              instVer == false)
 172             continue;
 173
 174          signed Prio = PFPriority[VF.File()->ID];
 175          if (Prio > Max)
 176          {
 177             Pref = Ver;
 178             Max = Prio;
 179          }
 180          if (Prio > MaxAlt)
 181          {
 182             PrefAlt = Ver;
 183             MaxAlt = Prio;
 184          }
 185       }
 186
 187       if (instVer == true && Max < 1000)
 188       {
 189          /* Elevate our current selection (or the status file itself)
 190             to the Pseudo-status priority. */
 191          if (Pref.end() == true)
 192             Pref = Ver;
 193          Max = 1000;
 194
 195          // Fast path optimize.
 196          if (StatusOverride == false)
 197             break;
 198       }
 199    }
 200    // If we do not find our candidate, use the one with the highest pin.
 201    // This means that if there is a version available with pin > 0; there
 202    // will always be a candidate (Closes: #512318)
 203    if (!Pref.IsGood() && MaxAlt > 0)
 204        Pref = PrefAlt;
 205
 206    return Pref;
 207 }
 208                                                                         /*}}}*/
 209 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 210 // ---------------------------------------------------------------------
 211 /* For performance we have 3 tables, the default table, the main cache
 212    table (hashed to the cache). A blank package name indicates the pin
 213    belongs to the default table. Order of insertion matters here, the
 214    earlier defaults override later ones. */
 215 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 216                           string Data,signed short Priority)
 217 {
 218    if (Name.empty() == true)
 219    {
 220       Pin *P = &*Defaults.insert(Defaults.end(),PkgPin());
 221       P->Type = Type;
 222       P->Priority = Priority;
 223       P->Data = Data;
 224       return;
 225    }
 226
 227    // Get a spot to put the pin
 228    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 229    for (pkgCache::PkgIterator Pkg = Grp.FindPkg("any");
 230         Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 231    {
 232       Pin *P = 0;
 233       if (Pkg.end() == false)
 234          P = Pins + Pkg->ID;
 235       else
 236       {
 237          // Check the unmatched table
 238          for (vector<PkgPin>::iterator I = Unmatched.begin();
 239               I != Unmatched.end() && P == 0; I++)
 240             if (I->Pkg == Name)
 241                P = &*I;
 242
 243          if (P == 0)
 244             P = &*Unmatched.insert(Unmatched.end(),PkgPin());
 245       }
 246       P->Type = Type;
 247       P->Priority = Priority;
 248       P->Data = Data;
 249    }
 250 }
 251                                                                         /*}}}*/
 252 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 253 // ---------------------------------------------------------------------
 254 /* */
 255 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 256 {
 257    const Pin &PPkg = Pins[Pkg->ID];
 258    if (PPkg.Type == pkgVersionMatch::None)
 259       return pkgCache::VerIterator(*Pkg.Cache());
 260
 261    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 262    return Match.Find(Pkg);
 263 }
 264                                                                         /*}}}*/
 265 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 266 // ---------------------------------------------------------------------
 267 /* */
 268 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 269 {
 270    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 271    {
 272       // In this case 0 means default priority
 273       if (Pins[Pkg->ID].Priority == 0)
 274          return 989;
 275       return Pins[Pkg->ID].Priority;
 276    }
 277
 278    return 0;
 279 }
 280                                                                         /*}}}*/
 281 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 282 // ---------------------------------------------------------------------
 283 /* The preference file is a user generated file so the parser should
 284    therefore be a bit more friendly by allowing comments and new lines
 285    all over the place rather than forcing a special format */
 286 class PreferenceSection : public pkgTagSection
 287 {
 288    void TrimRecord(bool BeforeRecord, const char* &End)
 289    {
 290       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 291          if (Stop[0] == '#')
 292             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 293    }
 294 };
 295                                                                         /*}}}*/
 296 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 297 // ---------------------------------------------------------------------
 298 /* This will load each pin file in the given dir into a Policy. If the
 299    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 300    Note also that this method will issue a warning if the dir does not
 301    exists but it will return true in this case! */
 302 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 303 {
 304    if (Dir.empty() == true)
 305       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 306
 307    if (DirectoryExists(Dir) == false)
 308    {
 309       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 310       return true;
 311    }
 312
 313    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 314
 315    // Read the files
 316    for (vector<string>::const_iterator I = List.begin(); I != List.end(); I++)
 317       if (ReadPinFile(Plcy, *I) == false)
 318          return false;
 319    return true;
 320 }
 321                                                                         /*}}}*/
 322 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 323 // ---------------------------------------------------------------------
 324 /* I'd like to see the preferences file store more than just pin information
 325    but right now that is the only stuff I have to store. Later there will
 326    have to be some kind of combined super parser to get the data into all
 327    the right classes.. */
 328 bool ReadPinFile(pkgPolicy &Plcy,string File)
 329 {
 330    if (File.empty() == true)
 331       File = _config->FindFile("Dir::Etc::Preferences");
 332
 333    if (RealFileExists(File) == false)
 334       return true;
 335
 336    FileFd Fd(File,FileFd::ReadOnly);
 337    pkgTagFile TF(&Fd);
 338    if (_error->PendingError() == true)
 339       return false;
 340
 341    PreferenceSection Tags;
 342    while (TF.Step(Tags) == true)
 343    {
 344       string Name = Tags.FindS("Package");
 345       if (Name.empty() == true)
 346          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 347       if (Name == "*")
 348          Name = string();
 349
 350       const char *Start;
 351       const char *End;
 352       if (Tags.Find("Pin",Start,End) == false)
 353          continue;
 354
 355       const char *Word = Start;
 356       for (; Word != End && isspace(*Word) == 0; Word++);
 357
 358       // Parse the type..
 359       pkgVersionMatch::MatchType Type;
 360       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 361          Type = pkgVersionMatch::Version;
 362       else if (stringcasecmp(Start,Word,"release") == 0)
 363          Type = pkgVersionMatch::Release;
 364       else if (stringcasecmp(Start,Word,"origin") == 0)
 365          Type = pkgVersionMatch::Origin;
 366       else
 367       {
 368          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 369          continue;
 370       }
 371       for (; Word != End && isspace(*Word) != 0; Word++);
 372
 373       short int priority = Tags.FindI("Pin-Priority", 0);
 374       if (priority == 0)
 375       {
 376          _error->Warning(_("No priority (or zero) specified for pin"));
 377          continue;
 378       }
 379
 380       istringstream s(Name);
 381       string pkg;
 382       while(!s.eof())
 383       {
 384          s >> pkg;
 385          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 386       };
 387    }
 388
 389    Plcy.InitDefaults();
 390    return true;
 391 }
 392                                                                         /*}}}*/