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