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<config.h>
  27
  28 #include <apt-pkg/policy.h>
  29 #include <apt-pkg/configuration.h>
  30 #include <apt-pkg/cachefilter.h>
  31 #include <apt-pkg/tagfile.h>
  32 #include <apt-pkg/strutl.h>
  33 #include <apt-pkg/fileutl.h>
  34 #include <apt-pkg/error.h>
  35 #include <apt-pkg/sptr.h>
  36
  37 #include <iostream>
  38 #include <sstream>
  39
  40 #include <apti18n.h>
  41                                                                         /*}}}*/
  42
  43 using namespace std;
  44
  45 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  46 // ---------------------------------------------------------------------
  47 /* Set the defaults for operation. The default mode with no loaded policy
  48    file matches the V0 policy engine. */
  49 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  50 {
  51    if (Owner == 0 || &(Owner->Head()) == 0)
  52       return;
  53    PFPriority = new signed short[Owner->Head().PackageFileCount];
  54    Pins = new Pin[Owner->Head().PackageCount];
  55
  56    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  57       Pins[I].Type = pkgVersionMatch::None;
  58
  59    // The config file has a master override.
  60    string DefRel = _config->Find("APT::Default-Release");
  61    if (DefRel.empty() == false)
  62    {
  63       bool found = false;
  64       // FIXME: make ExpressionMatches static to use it here easily
  65       pkgVersionMatch vm("", pkgVersionMatch::None);
  66       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
  67       {
  68          if ((F->Archive != 0 && vm.ExpressionMatches(DefRel, F.Archive()) == true) ||
  69              (F->Codename != 0 && vm.ExpressionMatches(DefRel, F.Codename()) == true) ||
  70              (F->Version != 0 && vm.ExpressionMatches(DefRel, F.Version()) == true) ||
  71              (DefRel.length() > 2 && DefRel[1] == '='))
  72             found = true;
  73       }
  74       if (found == false)
  75          _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
  76       else
  77          CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  78    }
  79    InitDefaults();
  80 }
  81                                                                         /*}}}*/
  82 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  83 // ---------------------------------------------------------------------
  84 /* */
  85 bool pkgPolicy::InitDefaults()
  86 {
  87    // Initialize the priorities based on the status of the package file
  88    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
  89    {
  90       PFPriority[I->ID] = 500;
  91       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  92          PFPriority[I->ID] = 100;
  93       else if ((I->Flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
  94          PFPriority[I->ID] = 100;
  95       else if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  96          PFPriority[I->ID] = 1;
  97    }
  98
  99    // Apply the defaults..
 100    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
 101    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
 102    signed Cur = 989;
 103    StatusOverride = false;
 104    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
 105         ++I, --Cur)
 106    {
 107       pkgVersionMatch Match(I->Data,I->Type);
 108       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 109       {
 110          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
 111          {
 112             if (I->Priority != 0 && I->Priority > 0)
 113                Cur = I->Priority;
 114
 115             if (I->Priority < 0)
 116                PFPriority[F->ID] =  I->Priority;
 117             else
 118                PFPriority[F->ID] = Cur;
 119
 120             if (PFPriority[F->ID] > 1000)
 121                StatusOverride = true;
 122
 123             Fixed[F->ID] = true;
 124          }
 125       }
 126    }
 127
 128    if (_config->FindB("Debug::pkgPolicy",false) == true)
 129       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 130          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 131
 132    return true;
 133 }
 134                                                                         /*}}}*/
 135 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 136 // ---------------------------------------------------------------------
 137 /* Evaluate the package pins and the default list to deteremine what the
 138    best package is. */
 139 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 140 {
 141    // Look for a package pin and evaluate it.
 142    signed Max = GetPriority(Pkg);
 143    pkgCache::VerIterator Pref = GetMatch(Pkg);
 144
 145    // Alternatives in case we can not find our package pin (Bug#512318).
 146    signed MaxAlt = 0;
 147    pkgCache::VerIterator PrefAlt;
 148
 149    // no package = no candidate version
 150    if (Pkg.end() == true)
 151       return Pref;
 152
 153    // packages with a pin lower than 0 have no newer candidate than the current version
 154    if (Max < 0)
 155       return Pkg.CurrentVer();
 156
 157    /* Falling through to the default version.. Setting Max to zero
 158       effectively excludes everything <= 0 which are the non-automatic
 159       priorities.. The status file is given a prio of 100 which will exclude
 160       not-automatic sources, except in a single shot not-installed mode.
 161       The second pseduo-status file is at prio 1000, above which will permit
 162       the user to force-downgrade things.
 163
 164       The user pin is subject to the same priority rules as default
 165       selections. Thus there are two ways to create a pin - a pin that
 166       tracks the default when the default is taken away, and a permanent
 167       pin that stays at that setting.
 168     */
 169    bool PrefSeen = false;
 170    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
 171    {
 172       /* Lets see if this version is the installed version */
 173       bool instVer = (Pkg.CurrentVer() == Ver);
 174
 175       if (Pref == Ver)
 176          PrefSeen = true;
 177
 178       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
 179       {
 180          /* If this is the status file, and the current version is not the
 181             version in the status file (ie it is not installed, or somesuch)
 182             then it is not a candidate for installation, ever. This weeds
 183             out bogus entries that may be due to config-file states, or
 184             other. */
 185          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 186              instVer == false)
 187             continue;
 188
 189          signed Prio = PFPriority[VF.File()->ID];
 190          if (Prio > Max)
 191          {
 192             Pref = Ver;
 193             Max = Prio;
 194             PrefSeen = true;
 195          }
 196          if (Prio > MaxAlt)
 197          {
 198             PrefAlt = Ver;
 199             MaxAlt = Prio;
 200          }
 201       }
 202
 203       if (instVer == true && Max < 1000)
 204       {
 205          /* Not having seen the Pref yet means we have a specific pin below 1000
 206             on a version below the current installed one, so ignore the specific pin
 207             as this would be a downgrade otherwise */
 208          if (PrefSeen == false || Pref.end() == true)
 209          {
 210             Pref = Ver;
 211             PrefSeen = true;
 212          }
 213          /* Elevate our current selection (or the status file itself)
 214             to the Pseudo-status priority. */
 215          Max = 1000;
 216
 217          // Fast path optimize.
 218          if (StatusOverride == false)
 219             break;
 220       }
 221    }
 222    // If we do not find our candidate, use the one with the highest pin.
 223    // This means that if there is a version available with pin > 0; there
 224    // will always be a candidate (Closes: #512318)
 225    if (!Pref.IsGood() && MaxAlt > 0)
 226        Pref = PrefAlt;
 227
 228    return Pref;
 229 }
 230                                                                         /*}}}*/
 231 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 232 // ---------------------------------------------------------------------
 233 /* For performance we have 3 tables, the default table, the main cache
 234    table (hashed to the cache). A blank package name indicates the pin
 235    belongs to the default table. Order of insertion matters here, the
 236    earlier defaults override later ones. */
 237 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 238                           string Data,signed short Priority)
 239 {
 240    if (Name.empty() == true)
 241    {
 242       Pin *P = &*Defaults.insert(Defaults.end(),Pin());
 243       P->Type = Type;
 244       P->Priority = Priority;
 245       P->Data = Data;
 246       return;
 247    }
 248
 249    size_t found = Name.rfind(':');
 250    string Arch;
 251    if (found != string::npos) {
 252       Arch = Name.substr(found+1);
 253       Name.erase(found);
 254    }
 255
 256    // Allow pinning by wildcards
 257    // TODO: Maybe we should always prefer specific pins over non-
 258    // specific ones.
 259    if (Name[0] == '/' || Name.find_first_of("*[?") != string::npos)
 260    {
 261       pkgVersionMatch match(Data, Type);
 262       for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
 263          if (match.ExpressionMatches(Name, G.Name()))
 264          {
 265             if (Arch.empty() == false)
 266                CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
 267             else
 268                CreatePin(Type, G.Name(), Data, Priority);
 269          }
 270       return;
 271    }
 272
 273    // find the package (group) this pin applies to
 274    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 275    bool matched = false;
 276    if (Grp.end() == false)
 277    {
 278       std::string MatchingArch;
 279       if (Arch.empty() == true)
 280          MatchingArch = Cache->NativeArch();
 281       else
 282          MatchingArch = Arch;
 283       APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
 284       for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 285       {
 286          if (pams(Pkg.Arch()) == false)
 287             continue;
 288          Pin *P = Pins + Pkg->ID;
 289          // the first specific stanza for a package is the ruler,
 290          // all others need to be ignored
 291          if (P->Type != pkgVersionMatch::None)
 292             P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
 293          P->Type = Type;
 294          P->Priority = Priority;
 295          P->Data = Data;
 296          matched = true;
 297       }
 298    }
 299
 300    if (matched == false)
 301    {
 302       PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
 303       if (Arch.empty() == false)
 304          P->Pkg.append(":").append(Arch);
 305       P->Type = Type;
 306       P->Priority = Priority;
 307       P->Data = Data;
 308       return;
 309    }
 310 }
 311                                                                         /*}}}*/
 312 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 313 // ---------------------------------------------------------------------
 314 /* */
 315 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 316 {
 317    const Pin &PPkg = Pins[Pkg->ID];
 318    if (PPkg.Type == pkgVersionMatch::None)
 319       return pkgCache::VerIterator(*Pkg.Cache());
 320
 321    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 322    return Match.Find(Pkg);
 323 }
 324                                                                         /*}}}*/
 325 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 326 // ---------------------------------------------------------------------
 327 /* */
 328 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 329 {
 330    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 331    {
 332       // In this case 0 means default priority
 333       if (Pins[Pkg->ID].Priority == 0)
 334          return 989;
 335       return Pins[Pkg->ID].Priority;
 336    }
 337
 338    return 0;
 339 }
 340 signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
 341 {
 342    return PFPriority[File->ID];
 343 }
 344                                                                         /*}}}*/
 345 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 346 // ---------------------------------------------------------------------
 347 /* The preference file is a user generated file so the parser should
 348    therefore be a bit more friendly by allowing comments and new lines
 349    all over the place rather than forcing a special format */
 350 class PreferenceSection : public pkgTagSection
 351 {
 352    void TrimRecord(bool BeforeRecord, const char* &End)
 353    {
 354       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 355          if (Stop[0] == '#')
 356             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 357    }
 358 };
 359                                                                         /*}}}*/
 360 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 361 // ---------------------------------------------------------------------
 362 /* This will load each pin file in the given dir into a Policy. If the
 363    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 364    Note also that this method will issue a warning if the dir does not
 365    exists but it will return true in this case! */
 366 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 367 {
 368    if (Dir.empty() == true)
 369       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 370
 371    if (DirectoryExists(Dir) == false)
 372    {
 373       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 374       return true;
 375    }
 376
 377    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 378
 379    // Read the files
 380    for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
 381       if (ReadPinFile(Plcy, *I) == false)
 382          return false;
 383    return true;
 384 }
 385                                                                         /*}}}*/
 386 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 387 // ---------------------------------------------------------------------
 388 /* I'd like to see the preferences file store more than just pin information
 389    but right now that is the only stuff I have to store. Later there will
 390    have to be some kind of combined super parser to get the data into all
 391    the right classes.. */
 392 bool ReadPinFile(pkgPolicy &Plcy,string File)
 393 {
 394    if (File.empty() == true)
 395       File = _config->FindFile("Dir::Etc::Preferences");
 396
 397    if (RealFileExists(File) == false)
 398       return true;
 399
 400    FileFd Fd(File,FileFd::ReadOnly);
 401    pkgTagFile TF(&Fd);
 402    if (_error->PendingError() == true)
 403       return false;
 404
 405    PreferenceSection Tags;
 406    while (TF.Step(Tags) == true)
 407    {
 408       // can happen when there are only comments in a record
 409       if (Tags.Count() == 0)
 410          continue;
 411
 412       string Name = Tags.FindS("Package");
 413       if (Name.empty() == true)
 414          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 415       if (Name == "*")
 416          Name = string();
 417
 418       const char *Start;
 419       const char *End;
 420       if (Tags.Find("Pin",Start,End) == false)
 421          continue;
 422
 423       const char *Word = Start;
 424       for (; Word != End && isspace(*Word) == 0; Word++);
 425
 426       // Parse the type..
 427       pkgVersionMatch::MatchType Type;
 428       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 429          Type = pkgVersionMatch::Version;
 430       else if (stringcasecmp(Start,Word,"release") == 0)
 431          Type = pkgVersionMatch::Release;
 432       else if (stringcasecmp(Start,Word,"origin") == 0)
 433          Type = pkgVersionMatch::Origin;
 434       else
 435       {
 436          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 437          continue;
 438       }
 439       for (; Word != End && isspace(*Word) != 0; Word++);
 440
 441       short int priority = Tags.FindI("Pin-Priority", 0);
 442       if (priority == 0)
 443       {
 444          _error->Warning(_("No priority (or zero) specified for pin"));
 445          continue;
 446       }
 447
 448       istringstream s(Name);
 449       string pkg;
 450       while(!s.eof())
 451       {
 452          s >> pkg;
 453          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 454       };
 455    }
 456
 457    Plcy.InitDefaults();
 458    return true;
 459 }
 460                                                                         /*}}}*/