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/cacheiterators.h>
  26 #include <apt-pkg/pkgcache.h>
  27 #include <apt-pkg/versionmatch.h>
  28 #include <apt-pkg/version.h>
  29
  30 #include <ctype.h>
  31 #include <stddef.h>
  32 #include <string.h>
  33 #include <string>
  34 #include <vector>
  35 #include <iostream>
  36 #include <sstream>
  37
  38 #include <apti18n.h>
  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(nullptr), VerPins(nullptr),
  48    PFPriority(nullptr), Cache(Owner), d(NULL)
  49 {
  50    if (Owner == 0)
  51       return;
  52    PFPriority = new signed short[Owner->Head().PackageFileCount];
  53    Pins = new Pin[Owner->Head().PackageCount];
  54    VerPins = new Pin[Owner->Head().VersionCount];
  55
  56    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  57       Pins[I].Type = pkgVersionMatch::None;
  58    for (unsigned long I = 0; I != Owner->Head().VersionCount; I++)
  59       VerPins[I].Type = pkgVersionMatch::None;
  60
  61    // The config file has a master override.
  62    string DefRel = _config->Find("APT::Default-Release");
  63    if (DefRel.empty() == false)
  64    {
  65       bool found = false;
  66       // FIXME: make ExpressionMatches static to use it here easily
  67       pkgVersionMatch vm("", pkgVersionMatch::None);
  68       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
  69       {
  70          if (vm.ExpressionMatches(DefRel, F.Archive()) ||
  71              vm.ExpressionMatches(DefRel, F.Codename()) ||
  72              vm.ExpressionMatches(DefRel, F.Version()) ||
  73              (DefRel.length() > 2 && DefRel[1] == '='))
  74             found = true;
  75       }
  76       if (found == false)
  77          _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
  78       else
  79          CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  80    }
  81    InitDefaults();
  82 }
  83                                                                         /*}}}*/
  84 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  85 // ---------------------------------------------------------------------
  86 /* */
  87 bool pkgPolicy::InitDefaults()
  88 {
  89    // Initialize the priorities based on the status of the package file
  90    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
  91    {
  92       PFPriority[I->ID] = 500;
  93       if (I.Flagged(pkgCache::Flag::NotSource))
  94          PFPriority[I->ID] = 100;
  95       else if (I.Flagged(pkgCache::Flag::ButAutomaticUpgrades))
  96          PFPriority[I->ID] = 100;
  97       else if (I.Flagged(pkgCache::Flag::NotAutomatic))
  98          PFPriority[I->ID] = 1;
  99    }
 100
 101    // Apply the defaults..
 102    std::unique_ptr<bool[]> Fixed(new bool[Cache->HeaderP->PackageFileCount]);
 103    memset(Fixed.get(),0,sizeof(Fixed[0])*Cache->HeaderP->PackageFileCount);
 104    StatusOverride = false;
 105    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end(); ++I)
 106    {
 107       pkgVersionMatch Match(I->Data,I->Type);
 108       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 109       {
 110          if (Fixed[F->ID] == false && Match.FileMatch(F) == true)
 111          {
 112             PFPriority[F->ID] = I->Priority;
 113
 114             if (PFPriority[F->ID] >= 1000)
 115                StatusOverride = true;
 116
 117             Fixed[F->ID] = true;
 118          }
 119       }
 120    }
 121
 122    if (_config->FindB("Debug::pkgPolicy",false) == true)
 123       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 124          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 125
 126    return true;
 127 }
 128                                                                         /*}}}*/
 129 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 130 // ---------------------------------------------------------------------
 131 /* Evaluate the package pins and the default list to deteremine what the
 132    best package is. */
 133 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 134 {
 135    if (_config->FindI("APT::Policy", 1) >= 1) {
 136       return GetCandidateVerNew(Pkg);
 137    }
 138
 139    // Look for a package pin and evaluate it.
 140    signed Max = GetPriority(Pkg);
 141    pkgCache::VerIterator Pref = GetMatch(Pkg);
 142
 143    // Alternatives in case we can not find our package pin (Bug#512318).
 144    signed MaxAlt = 0;
 145    pkgCache::VerIterator PrefAlt;
 146
 147    // no package = no candidate version
 148    if (Pkg.end() == true)
 149       return Pref;
 150
 151    // packages with a pin lower than 0 have no newer candidate than the current version
 152    if (Max < 0)
 153       return Pkg.CurrentVer();
 154
 155    /* Falling through to the default version.. Setting Max to zero
 156       effectively excludes everything <= 0 which are the non-automatic
 157       priorities.. The status file is given a prio of 100 which will exclude
 158       not-automatic sources, except in a single shot not-installed mode.
 159
 160       The user pin is subject to the same priority rules as default
 161       selections. Thus there are two ways to create a pin - a pin that
 162       tracks the default when the default is taken away, and a permanent
 163       pin that stays at that setting.
 164     */
 165    bool PrefSeen = false;
 166    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
 167    {
 168       /* Lets see if this version is the installed version */
 169       bool instVer = (Pkg.CurrentVer() == Ver);
 170
 171       if (Pref == Ver)
 172          PrefSeen = true;
 173
 174       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
 175       {
 176          /* If this is the status file, and the current version is not the
 177             version in the status file (ie it is not installed, or somesuch)
 178             then it is not a candidate for installation, ever. This weeds
 179             out bogus entries that may be due to config-file states, or
 180             other. */
 181          if (VF.File().Flagged(pkgCache::Flag::NotSource) && instVer == false)
 182             continue;
 183
 184          signed Prio = PFPriority[VF.File()->ID];
 185          if (Prio > Max)
 186          {
 187             Pref = Ver;
 188             Max = Prio;
 189             PrefSeen = true;
 190          }
 191          if (Prio > MaxAlt)
 192          {
 193             PrefAlt = Ver;
 194             MaxAlt = Prio;
 195          }
 196       }
 197
 198       if (instVer == true && Max < 1000)
 199       {
 200          /* Not having seen the Pref yet means we have a specific pin below 1000
 201             on a version below the current installed one, so ignore the specific pin
 202             as this would be a downgrade otherwise */
 203          if (PrefSeen == false || Pref.end() == true)
 204          {
 205             Pref = Ver;
 206             PrefSeen = true;
 207          }
 208          /* Elevate our current selection (or the status file itself) so that only
 209             a downgrade can override it from now on */
 210          Max = 999;
 211
 212          // Fast path optimize.
 213          if (StatusOverride == false)
 214             break;
 215       }
 216    }
 217    // If we do not find our candidate, use the one with the highest pin.
 218    // This means that if there is a version available with pin > 0; there
 219    // will always be a candidate (Closes: #512318)
 220    if (!Pref.IsGood() && MaxAlt > 0)
 221        Pref = PrefAlt;
 222
 223    return Pref;
 224 }
 225                                                                         /*}}}*/
 226 // Policy::GetCandidateVerNew - Get the candidate install version       /*{{{*/
 227 // ---------------------------------------------------------------------
 228 /* Evaluate the package pins and the default list to deteremine what the
 229    best package is. */
 230 pkgCache::VerIterator pkgPolicy::GetCandidateVerNew(pkgCache::PkgIterator const &Pkg)
 231 {
 232    // TODO: Replace GetCandidateVer()
 233    pkgCache::VerIterator cand;
 234    pkgCache::VerIterator cur = Pkg.CurrentVer();
 235    int candPriority = -1;
 236    pkgVersioningSystem *vs = Cache->VS;
 237
 238    for (pkgCache::VerIterator ver = Pkg.VersionList(); ver.end() == false; ++ver) {
 239       int priority = GetPriority(ver, true);
 240
 241       if (priority == 0 || priority <= candPriority)
 242          continue;
 243
 244       // TODO: Maybe optimize to not compare versions
 245       if (!cur.end() && priority < 1000
 246           && (vs->CmpVersion(ver.VerStr(), cur.VerStr()) < 0))
 247          continue;
 248
 249       candPriority = priority;
 250       cand = ver;
 251    }
 252
 253    return cand;
 254 }
 255                                                                         /*}}}*/
 256 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 257 // ---------------------------------------------------------------------
 258 /* For performance we have 3 tables, the default table, the main cache
 259    table (hashed to the cache). A blank package name indicates the pin
 260    belongs to the default table. Order of insertion matters here, the
 261    earlier defaults override later ones. */
 262 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 263                           string Data,signed short Priority)
 264 {
 265    if (Name.empty() == true)
 266    {
 267       Pin *P = &*Defaults.insert(Defaults.end(),Pin());
 268       P->Type = Type;
 269       P->Priority = Priority;
 270       P->Data = Data;
 271       return;
 272    }
 273
 274    size_t found = Name.rfind(':');
 275    string Arch;
 276    if (found != string::npos) {
 277       Arch = Name.substr(found+1);
 278       Name.erase(found);
 279    }
 280
 281    // Allow pinning by wildcards - beware of package names looking like wildcards!
 282    // TODO: Maybe we should always prefer specific pins over non-specific ones.
 283    if ((Name[0] == '/' && Name[Name.length() - 1] == '/') || Name.find_first_of("*[?") != string::npos)
 284    {
 285       pkgVersionMatch match(Data, Type);
 286       for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
 287          if (Name != G.Name() && match.ExpressionMatches(Name, G.Name()))
 288          {
 289             if (Arch.empty() == false)
 290                CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
 291             else
 292                CreatePin(Type, G.Name(), Data, Priority);
 293          }
 294       return;
 295    }
 296
 297    // find the package (group) this pin applies to
 298    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 299    bool matched = false;
 300    if (Grp.end() == false)
 301    {
 302       std::string MatchingArch;
 303       if (Arch.empty() == true)
 304          MatchingArch = Cache->NativeArch();
 305       else
 306          MatchingArch = Arch;
 307       APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
 308       for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 309       {
 310          if (pams(Pkg.Arch()) == false)
 311             continue;
 312          Pin *P = Pins + Pkg->ID;
 313          // the first specific stanza for a package is the ruler,
 314          // all others need to be ignored
 315          if (P->Type != pkgVersionMatch::None)
 316             P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
 317          P->Type = Type;
 318          P->Priority = Priority;
 319          P->Data = Data;
 320          matched = true;
 321
 322          // Find matching version(s) and copy the pin into it
 323          pkgVersionMatch Match(P->Data,P->Type);
 324          for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() != true; ++Ver)
 325          {
 326             if (Match.VersionMatches(Ver)) {
 327                Pin *VP = VerPins + Ver->ID;
 328                if (VP->Type == pkgVersionMatch::None)
 329                   *VP = *P;
 330             }
 331          }
 332       }
 333    }
 334
 335    if (matched == false)
 336    {
 337       PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
 338       if (Arch.empty() == false)
 339          P->Pkg.append(":").append(Arch);
 340       P->Type = Type;
 341       P->Priority = Priority;
 342       P->Data = Data;
 343       return;
 344    }
 345 }
 346                                                                         /*}}}*/
 347 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 348 // ---------------------------------------------------------------------
 349 /* */
 350 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 351 {
 352    const Pin &PPkg = Pins[Pkg->ID];
 353    if (PPkg.Type == pkgVersionMatch::None)
 354       return pkgCache::VerIterator(*Pkg.Cache());
 355
 356    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 357    return Match.Find(Pkg);
 358 }
 359                                                                         /*}}}*/
 360 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 361 // ---------------------------------------------------------------------
 362 /* */
 363 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 364 {
 365    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 366       return Pins[Pkg->ID].Priority;
 367    return 0;
 368 }
 369 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::VerIterator const &Ver, bool ConsiderFiles)
 370 {
 371    if (VerPins[Ver->ID].Type != pkgVersionMatch::None)
 372       return VerPins[Ver->ID].Priority;
 373    if (!ConsiderFiles)
 374       return 0;
 375
 376    int priority = std::numeric_limits<int>::min();
 377    for (pkgCache::VerFileIterator file = Ver.FileList(); file.end() == false; file++)
 378    {
 379       /* If this is the status file, and the current version is not the
 380          version in the status file (ie it is not installed, or somesuch)
 381          then it is not a candidate for installation, ever. This weeds
 382          out bogus entries that may be due to config-file states, or
 383          other. */
 384       if (file.File().Flagged(pkgCache::Flag::NotSource) && Ver.ParentPkg().CurrentVer() != Ver) {
 385          // Ignore
 386       } else if (GetPriority(file.File()) > priority) {
 387          priority = GetPriority(file.File());
 388       }
 389    }
 390
 391    return priority == std::numeric_limits<int>::min() ? 0 : priority;
 392 }
 393 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
 394 {
 395    return PFPriority[File->ID];
 396 }
 397                                                                         /*}}}*/
 398 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 399 // ---------------------------------------------------------------------
 400 /* This will load each pin file in the given dir into a Policy. If the
 401    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 402    Note also that this method will issue a warning if the dir does not
 403    exists but it will return true in this case! */
 404 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 405 {
 406    if (Dir.empty() == true)
 407       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 408
 409    if (DirectoryExists(Dir) == false)
 410    {
 411       if (Dir != "/dev/null")
 412          _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 413       return true;
 414    }
 415
 416    _error->PushToStack();
 417    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 418    bool const PendingErrors = _error->PendingError();
 419    _error->MergeWithStack();
 420    if (PendingErrors)
 421       return false;
 422
 423    // Read the files
 424    for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
 425       if (ReadPinFile(Plcy, *I) == false)
 426          return false;
 427    return true;
 428 }
 429                                                                         /*}}}*/
 430 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 431 // ---------------------------------------------------------------------
 432 /* I'd like to see the preferences file store more than just pin information
 433    but right now that is the only stuff I have to store. Later there will
 434    have to be some kind of combined super parser to get the data into all
 435    the right classes.. */
 436 bool ReadPinFile(pkgPolicy &Plcy,string File)
 437 {
 438    if (File.empty() == true)
 439       File = _config->FindFile("Dir::Etc::Preferences");
 440
 441    if (RealFileExists(File) == false)
 442       return true;
 443
 444    FileFd Fd(File,FileFd::ReadOnly);
 445    pkgTagFile TF(&Fd, pkgTagFile::SUPPORT_COMMENTS);
 446    if (Fd.IsOpen() == false || Fd.Failed())
 447       return false;
 448
 449    pkgTagSection Tags;
 450    while (TF.Step(Tags) == true)
 451    {
 452       // can happen when there are only comments in a record
 453       if (Tags.Count() == 0)
 454          continue;
 455
 456       string Name = Tags.FindS("Package");
 457       if (Name.empty() == true)
 458          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 459       if (Name == "*")
 460          Name = string();
 461
 462       const char *Start;
 463       const char *End;
 464       if (Tags.Find("Pin",Start,End) == false)
 465          continue;
 466
 467       const char *Word = Start;
 468       for (; Word != End && isspace(*Word) == 0; Word++);
 469
 470       // Parse the type..
 471       pkgVersionMatch::MatchType Type;
 472       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 473          Type = pkgVersionMatch::Version;
 474       else if (stringcasecmp(Start,Word,"release") == 0)
 475          Type = pkgVersionMatch::Release;
 476       else if (stringcasecmp(Start,Word,"origin") == 0)
 477          Type = pkgVersionMatch::Origin;
 478       else
 479       {
 480          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 481          continue;
 482       }
 483       for (; Word != End && isspace(*Word) != 0; Word++);
 484
 485       _error->PushToStack();
 486       int const priority = Tags.FindI("Pin-Priority", 0);
 487       bool const newError = _error->PendingError();
 488       _error->MergeWithStack();
 489       if (priority < std::numeric_limits<short>::min() ||
 490           priority > std::numeric_limits<short>::max() ||
 491           newError) {
 492          return _error->Error(_("%s: Value %s is outside the range of valid pin priorities (%d to %d)"),
 493                               File.c_str(), Tags.FindS("Pin-Priority").c_str(),
 494                               std::numeric_limits<short>::min(),
 495                               std::numeric_limits<short>::max());
 496       }
 497       if (priority == 0)
 498       {
 499          return _error->Error(_("No priority (or zero) specified for pin"));
 500       }
 501
 502       istringstream s(Name);
 503       string pkg;
 504       while(!s.eof())
 505       {
 506          s >> pkg;
 507          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 508       };
 509    }
 510
 511    Plcy.InitDefaults();
 512    return true;
 513 }
 514                                                                         /*}}}*/
 515
 516 pkgPolicy::~pkgPolicy() {delete [] PFPriority; delete [] Pins; delete [] VerPins; }