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    See man apt_preferences for what value means what.
  12
  13    ##################################################################### */
  14                                                                         /*}}}*/
  15 // Include Files                                                        /*{{{*/
  16 #include<config.h>
  17
  18 #include <apt-pkg/policy.h>
  19 #include <apt-pkg/configuration.h>
  20 #include <apt-pkg/cachefilter.h>
  21 #include <apt-pkg/tagfile.h>
  22 #include <apt-pkg/strutl.h>
  23 #include <apt-pkg/fileutl.h>
  24 #include <apt-pkg/error.h>
  25 #include <apt-pkg/sptr.h>
  26 #include <apt-pkg/cacheiterators.h>
  27 #include <apt-pkg/pkgcache.h>
  28 #include <apt-pkg/versionmatch.h>
  29 #include <apt-pkg/version.h>
  30
  31 #include <ctype.h>
  32 #include <stddef.h>
  33 #include <string.h>
  34 #include <string>
  35 #include <vector>
  36 #include <iostream>
  37 #include <sstream>
  38
  39 #include <apti18n.h>
  40                                                                         /*}}}*/
  41
  42 using namespace std;
  43
  44 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  45 // ---------------------------------------------------------------------
  46 /* Set the defaults for operation. The default mode with no loaded policy
  47    file matches the V0 policy engine. */
  48 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(nullptr), VerPins(nullptr),
  49    PFPriority(nullptr), Cache(Owner), d(NULL)
  50 {
  51    if (Owner == 0)
  52       return;
  53    PFPriority = new signed short[Owner->Head().PackageFileCount];
  54    Pins = new Pin[Owner->Head().PackageCount];
  55    VerPins = new Pin[Owner->Head().VersionCount];
  56
  57    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  58       Pins[I].Type = pkgVersionMatch::None;
  59    for (unsigned long I = 0; I != Owner->Head().VersionCount; I++)
  60       VerPins[I].Type = pkgVersionMatch::None;
  61
  62    // The config file has a master override.
  63    string DefRel = _config->Find("APT::Default-Release");
  64    if (DefRel.empty() == false)
  65    {
  66       bool found = false;
  67       // FIXME: make ExpressionMatches static to use it here easily
  68       pkgVersionMatch vm("", pkgVersionMatch::None);
  69       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
  70       {
  71          if (vm.ExpressionMatches(DefRel, F.Archive()) ||
  72              vm.ExpressionMatches(DefRel, F.Codename()) ||
  73              vm.ExpressionMatches(DefRel, F.Version()) ||
  74              (DefRel.length() > 2 && DefRel[1] == '='))
  75             found = true;
  76       }
  77       if (found == false)
  78          _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
  79       else
  80          CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  81    }
  82    InitDefaults();
  83 }
  84                                                                         /*}}}*/
  85 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  86 // ---------------------------------------------------------------------
  87 /* */
  88 bool pkgPolicy::InitDefaults()
  89 {
  90    // Initialize the priorities based on the status of the package file
  91    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
  92    {
  93       PFPriority[I->ID] = 500;
  94       if (I.Flagged(pkgCache::Flag::NotSource))
  95          PFPriority[I->ID] = 100;
  96       else if (I.Flagged(pkgCache::Flag::ButAutomaticUpgrades))
  97          PFPriority[I->ID] = 100;
  98       else if (I.Flagged(pkgCache::Flag::NotAutomatic))
  99          PFPriority[I->ID] = 1;
 100    }
 101
 102    // Apply the defaults..
 103    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
 104    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
 105    StatusOverride = false;
 106    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end(); ++I)
 107    {
 108       pkgVersionMatch Match(I->Data,I->Type);
 109       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 110       {
 111          if (Fixed[F->ID] == false && Match.FileMatch(F) == true)
 112          {
 113             PFPriority[F->ID] = I->Priority;
 114
 115             if (PFPriority[F->ID] >= 1000)
 116                StatusOverride = true;
 117
 118             Fixed[F->ID] = true;
 119          }
 120       }
 121    }
 122
 123    if (_config->FindB("Debug::pkgPolicy",false) == true)
 124       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 125          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 126
 127    return true;
 128 }
 129                                                                         /*}}}*/
 130 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 131 // ---------------------------------------------------------------------
 132 /* Evaluate the package pins and the default list to deteremine what the
 133    best package is. */
 134 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 135 {
 136    if (_config->FindI("APT::Policy", 1) >= 1) {
 137       return GetCandidateVerNew(Pkg);
 138    }
 139
 140    // Look for a package pin and evaluate it.
 141    signed Max = GetPriority(Pkg);
 142    pkgCache::VerIterator Pref = GetMatch(Pkg);
 143
 144    // Alternatives in case we can not find our package pin (Bug#512318).
 145    signed MaxAlt = 0;
 146    pkgCache::VerIterator PrefAlt;
 147
 148    // no package = no candidate version
 149    if (Pkg.end() == true)
 150       return Pref;
 151
 152    // packages with a pin lower than 0 have no newer candidate than the current version
 153    if (Max < 0)
 154       return Pkg.CurrentVer();
 155
 156    /* Falling through to the default version.. Setting Max to zero
 157       effectively excludes everything <= 0 which are the non-automatic
 158       priorities.. The status file is given a prio of 100 which will exclude
 159       not-automatic sources, except in a single shot not-installed mode.
 160
 161       The user pin is subject to the same priority rules as default
 162       selections. Thus there are two ways to create a pin - a pin that
 163       tracks the default when the default is taken away, and a permanent
 164       pin that stays at that setting.
 165     */
 166    bool PrefSeen = false;
 167    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
 168    {
 169       /* Lets see if this version is the installed version */
 170       bool instVer = (Pkg.CurrentVer() == Ver);
 171
 172       if (Pref == Ver)
 173          PrefSeen = true;
 174
 175       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
 176       {
 177          /* If this is the status file, and the current version is not the
 178             version in the status file (ie it is not installed, or somesuch)
 179             then it is not a candidate for installation, ever. This weeds
 180             out bogus entries that may be due to config-file states, or
 181             other. */
 182          if (VF.File().Flagged(pkgCache::Flag::NotSource) && instVer == false)
 183             continue;
 184
 185          signed Prio = PFPriority[VF.File()->ID];
 186          if (Prio > Max)
 187          {
 188             Pref = Ver;
 189             Max = Prio;
 190             PrefSeen = true;
 191          }
 192          if (Prio > MaxAlt)
 193          {
 194             PrefAlt = Ver;
 195             MaxAlt = Prio;
 196          }
 197       }
 198
 199       if (instVer == true && Max < 1000)
 200       {
 201          /* Not having seen the Pref yet means we have a specific pin below 1000
 202             on a version below the current installed one, so ignore the specific pin
 203             as this would be a downgrade otherwise */
 204          if (PrefSeen == false || Pref.end() == true)
 205          {
 206             Pref = Ver;
 207             PrefSeen = true;
 208          }
 209          /* Elevate our current selection (or the status file itself) so that only
 210             a downgrade can override it from now on */
 211          Max = 999;
 212
 213          // Fast path optimize.
 214          if (StatusOverride == false)
 215             break;
 216       }
 217    }
 218    // If we do not find our candidate, use the one with the highest pin.
 219    // This means that if there is a version available with pin > 0; there
 220    // will always be a candidate (Closes: #512318)
 221    if (!Pref.IsGood() && MaxAlt > 0)
 222        Pref = PrefAlt;
 223
 224    return Pref;
 225 }
 226
 227 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 228 // ---------------------------------------------------------------------
 229 /* Evaluate the package pins and the default list to deteremine what the
 230    best package is. */
 231 pkgCache::VerIterator pkgPolicy::GetCandidateVerNew(pkgCache::PkgIterator const &Pkg)
 232 {
 233    // TODO: Replace GetCandidateVer()
 234    pkgCache::VerIterator cand;
 235    pkgCache::VerIterator cur = Pkg.CurrentVer();
 236    int candPriority = -1;
 237    pkgVersioningSystem *vs = Cache->VS;
 238
 239    for (pkgCache::VerIterator ver = Pkg.VersionList(); ver.end() == false; ver++) {
 240       int priority = GetPriority(ver);
 241
 242          if (priority == 0 || priority <= candPriority)
 243             continue;
 244
 245          // TODO: Maybe optimize to not compare versions
 246          if (!cur.end() && priority < 1000
 247             && (vs->CmpVersion(ver.VerStr(), cur.VerStr()) < 0))
 248             continue;
 249
 250       candPriority = priority;
 251       cand = ver;
 252    }
 253
 254    return cand;
 255 }
 256                                                                         /*}}}*/
 257 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 258 // ---------------------------------------------------------------------
 259 /* For performance we have 3 tables, the default table, the main cache
 260    table (hashed to the cache). A blank package name indicates the pin
 261    belongs to the default table. Order of insertion matters here, the
 262    earlier defaults override later ones. */
 263 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 264                           string Data,signed short Priority)
 265 {
 266    if (Name.empty() == true)
 267    {
 268       Pin *P = &*Defaults.insert(Defaults.end(),Pin());
 269       P->Type = Type;
 270       P->Priority = Priority;
 271       P->Data = Data;
 272       return;
 273    }
 274
 275    size_t found = Name.rfind(':');
 276    string Arch;
 277    if (found != string::npos) {
 278       Arch = Name.substr(found+1);
 279       Name.erase(found);
 280    }
 281
 282    // Allow pinning by wildcards
 283    // TODO: Maybe we should always prefer specific pins over non-
 284    // specific ones.
 285    if (Name[0] == '/' || Name.find_first_of("*[?") != string::npos)
 286    {
 287       pkgVersionMatch match(Data, Type);
 288       for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
 289          if (match.ExpressionMatches(Name, G.Name()))
 290          {
 291             if (Arch.empty() == false)
 292                CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
 293             else
 294                CreatePin(Type, G.Name(), Data, Priority);
 295          }
 296       return;
 297    }
 298
 299    // find the package (group) this pin applies to
 300    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 301    bool matched = false;
 302    if (Grp.end() == false)
 303    {
 304       std::string MatchingArch;
 305       if (Arch.empty() == true)
 306          MatchingArch = Cache->NativeArch();
 307       else
 308          MatchingArch = Arch;
 309       APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
 310       for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 311       {
 312          if (pams(Pkg.Arch()) == false)
 313             continue;
 314          Pin *P = Pins + Pkg->ID;
 315          // the first specific stanza for a package is the ruler,
 316          // all others need to be ignored
 317          if (P->Type != pkgVersionMatch::None)
 318             P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
 319          P->Type = Type;
 320          P->Priority = Priority;
 321          P->Data = Data;
 322          matched = true;
 323
 324          // Find matching version(s) and copy the pin into it
 325          pkgVersionMatch Match(P->Data,P->Type);
 326          for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() != true; Ver++)
 327          {
 328             if (Match.VersionMatches(Ver)) {
 329                Pin *VP = VerPins + Ver->ID;
 330                if (VP->Type == pkgVersionMatch::None)
 331                   *VP = *P;
 332             }
 333          }
 334       }
 335    }
 336
 337    if (matched == false)
 338    {
 339       PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
 340       if (Arch.empty() == false)
 341          P->Pkg.append(":").append(Arch);
 342       P->Type = Type;
 343       P->Priority = Priority;
 344       P->Data = Data;
 345       return;
 346    }
 347 }
 348                                                                         /*}}}*/
 349 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 350 // ---------------------------------------------------------------------
 351 /* */
 352 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 353 {
 354    const Pin &PPkg = Pins[Pkg->ID];
 355    if (PPkg.Type == pkgVersionMatch::None)
 356       return pkgCache::VerIterator(*Pkg.Cache());
 357
 358    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 359    return Match.Find(Pkg);
 360 }
 361                                                                         /*}}}*/
 362 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 363 // ---------------------------------------------------------------------
 364 /* */
 365 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 366 {
 367    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 368       return Pins[Pkg->ID].Priority;
 369    return 0;
 370 }
 371 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::VerIterator const &Ver)
 372 {
 373    if (VerPins[Ver->ID].Type != pkgVersionMatch::None)
 374       return VerPins[Ver->ID].Priority;
 375
 376
 377    int priority = std::numeric_limits<int>::min();
 378    for (pkgCache::VerFileIterator file = Ver.FileList(); file.end() == false; file++)
 379    {
 380       /* If this is the status file, and the current version is not the
 381          version in the status file (ie it is not installed, or somesuch)
 382          then it is not a candidate for installation, ever. This weeds
 383          out bogus entries that may be due to config-file states, or
 384          other. */
 385       if (file.File().Flagged(pkgCache::Flag::NotSource) && Ver.ParentPkg().CurrentVer() != Ver) {
 386          // Ignore
 387       } else if (GetPriority(file.File()) > priority) {
 388          priority = GetPriority(file.File());
 389       }
 390    }
 391
 392    return priority == std::numeric_limits<int>::min() ? 0 : priority;
 393 }
 394 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
 395 {
 396    return PFPriority[File->ID];
 397 }
 398                                                                         /*}}}*/
 399 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 400 // ---------------------------------------------------------------------
 401 /* This will load each pin file in the given dir into a Policy. If the
 402    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 403    Note also that this method will issue a warning if the dir does not
 404    exists but it will return true in this case! */
 405 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 406 {
 407    if (Dir.empty() == true)
 408       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 409
 410    if (DirectoryExists(Dir) == false)
 411    {
 412       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 413       return true;
 414    }
 415
 416    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 417
 418    // Read the files
 419    for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
 420       if (ReadPinFile(Plcy, *I) == false)
 421          return false;
 422    return true;
 423 }
 424                                                                         /*}}}*/
 425 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 426 // ---------------------------------------------------------------------
 427 /* I'd like to see the preferences file store more than just pin information
 428    but right now that is the only stuff I have to store. Later there will
 429    have to be some kind of combined super parser to get the data into all
 430    the right classes.. */
 431 bool ReadPinFile(pkgPolicy &Plcy,string File)
 432 {
 433    if (File.empty() == true)
 434       File = _config->FindFile("Dir::Etc::Preferences");
 435
 436    if (RealFileExists(File) == false)
 437       return true;
 438
 439    FileFd Fd(File,FileFd::ReadOnly);
 440    pkgTagFile TF(&Fd);
 441    if (_error->PendingError() == true)
 442       return false;
 443
 444    pkgUserTagSection Tags;
 445    while (TF.Step(Tags) == true)
 446    {
 447       // can happen when there are only comments in a record
 448       if (Tags.Count() == 0)
 449          continue;
 450
 451       string Name = Tags.FindS("Package");
 452       if (Name.empty() == true)
 453          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 454       if (Name == "*")
 455          Name = string();
 456
 457       const char *Start;
 458       const char *End;
 459       if (Tags.Find("Pin",Start,End) == false)
 460          continue;
 461
 462       const char *Word = Start;
 463       for (; Word != End && isspace(*Word) == 0; Word++);
 464
 465       // Parse the type..
 466       pkgVersionMatch::MatchType Type;
 467       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 468          Type = pkgVersionMatch::Version;
 469       else if (stringcasecmp(Start,Word,"release") == 0)
 470          Type = pkgVersionMatch::Release;
 471       else if (stringcasecmp(Start,Word,"origin") == 0)
 472          Type = pkgVersionMatch::Origin;
 473       else
 474       {
 475          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 476          continue;
 477       }
 478       for (; Word != End && isspace(*Word) != 0; Word++);
 479
 480       short int priority = Tags.FindI("Pin-Priority", 0);
 481       if (priority == 0)
 482       {
 483          _error->Warning(_("No priority (or zero) specified for pin"));
 484          continue;
 485       }
 486
 487       istringstream s(Name);
 488       string pkg;
 489       while(!s.eof())
 490       {
 491          s >> pkg;
 492          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 493       };
 494    }
 495
 496    Plcy.InitDefaults();
 497    return true;
 498 }
 499                                                                         /*}}}*/
 500
 501 pkgPolicy::~pkgPolicy() {delete [] PFPriority; delete [] Pins; delete [] VerPins; }