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 #include <apt-pkg/cacheiterators.h>
  37 #include <apt-pkg/pkgcache.h>
  38 #include <apt-pkg/versionmatch.h>
  39
  40 #include <ctype.h>
  41 #include <stddef.h>
  42 #include <string.h>
  43 #include <string>
  44 #include <vector>
  45 #include <iostream>
  46 #include <sstream>
  47
  48 #include <apti18n.h>
  49                                                                         /*}}}*/
  50
  51 using namespace std;
  52
  53 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  54 // ---------------------------------------------------------------------
  55 /* Set the defaults for operation. The default mode with no loaded policy
  56    file matches the V0 policy engine. */
  57 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  58 {
  59    if (Owner == 0 || &(Owner->Head()) == 0)
  60       return;
  61    PFPriority = new signed short[Owner->Head().PackageFileCount];
  62    Pins = new Pin[Owner->Head().PackageCount];
  63
  64    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  65       Pins[I].Type = pkgVersionMatch::None;
  66
  67    // The config file has a master override.
  68    string DefRel = _config->Find("APT::Default-Release");
  69    if (DefRel.empty() == false)
  70    {
  71       bool found = false;
  72       // FIXME: make ExpressionMatches static to use it here easily
  73       pkgVersionMatch vm("", pkgVersionMatch::None);
  74       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
  75       {
  76          if ((F->Archive != 0 && vm.ExpressionMatches(DefRel, F.Archive()) == true) ||
  77              (F->Codename != 0 && vm.ExpressionMatches(DefRel, F.Codename()) == true) ||
  78              (F->Version != 0 && vm.ExpressionMatches(DefRel, F.Version()) == true) ||
  79              (DefRel.length() > 2 && DefRel[1] == '='))
  80             found = true;
  81       }
  82       if (found == false)
  83          _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
  84       else
  85          CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  86    }
  87    InitDefaults();
  88 }
  89                                                                         /*}}}*/
  90 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  91 // ---------------------------------------------------------------------
  92 /* */
  93 bool pkgPolicy::InitDefaults()
  94 {
  95    // Initialize the priorities based on the status of the package file
  96    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
  97    {
  98       PFPriority[I->ID] = 500;
  99       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
 100          PFPriority[I->ID] = 100;
 101       else if ((I->Flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
 102          PFPriority[I->ID] = 100;
 103       else if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
 104          PFPriority[I->ID] = 1;
 105    }
 106
 107    // Apply the defaults..
 108    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
 109    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
 110    signed Cur = 989;
 111    StatusOverride = false;
 112    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
 113         ++I, --Cur)
 114    {
 115       pkgVersionMatch Match(I->Data,I->Type);
 116       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 117       {
 118          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
 119          {
 120             if (I->Priority != 0 && I->Priority > 0)
 121                Cur = I->Priority;
 122
 123             if (I->Priority < 0)
 124                PFPriority[F->ID] =  I->Priority;
 125             else
 126                PFPriority[F->ID] = Cur;
 127
 128             if (PFPriority[F->ID] > 1000)
 129                StatusOverride = true;
 130
 131             Fixed[F->ID] = true;
 132          }
 133       }
 134    }
 135
 136    if (_config->FindB("Debug::pkgPolicy",false) == true)
 137       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 138          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 139
 140    return true;
 141 }
 142                                                                         /*}}}*/
 143 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 144 // ---------------------------------------------------------------------
 145 /* Evaluate the package pins and the default list to deteremine what the
 146    best package is. */
 147 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 148 {
 149    // Look for a package pin and evaluate it.
 150    signed Max = GetPriority(Pkg);
 151    pkgCache::VerIterator Pref = GetMatch(Pkg);
 152
 153    // Alternatives in case we can not find our package pin (Bug#512318).
 154    signed MaxAlt = 0;
 155    pkgCache::VerIterator PrefAlt;
 156
 157    // no package = no candidate version
 158    if (Pkg.end() == true)
 159       return Pref;
 160
 161    // packages with a pin lower than 0 have no newer candidate than the current version
 162    if (Max < 0)
 163       return Pkg.CurrentVer();
 164
 165    /* Falling through to the default version.. Setting Max to zero
 166       effectively excludes everything <= 0 which are the non-automatic
 167       priorities.. The status file is given a prio of 100 which will exclude
 168       not-automatic sources, except in a single shot not-installed mode.
 169       The second pseduo-status file is at prio 1000, above which will permit
 170       the user to force-downgrade things.
 171
 172       The user pin is subject to the same priority rules as default
 173       selections. Thus there are two ways to create a pin - a pin that
 174       tracks the default when the default is taken away, and a permanent
 175       pin that stays at that setting.
 176     */
 177    bool PrefSeen = false;
 178    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
 179    {
 180       /* Lets see if this version is the installed version */
 181       bool instVer = (Pkg.CurrentVer() == Ver);
 182
 183       if (Pref == Ver)
 184          PrefSeen = true;
 185
 186       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
 187       {
 188          /* If this is the status file, and the current version is not the
 189             version in the status file (ie it is not installed, or somesuch)
 190             then it is not a candidate for installation, ever. This weeds
 191             out bogus entries that may be due to config-file states, or
 192             other. */
 193          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 194              instVer == false)
 195             continue;
 196
 197          signed Prio = PFPriority[VF.File()->ID];
 198          if (Prio > Max)
 199          {
 200             Pref = Ver;
 201             Max = Prio;
 202             PrefSeen = true;
 203          }
 204          if (Prio > MaxAlt)
 205          {
 206             PrefAlt = Ver;
 207             MaxAlt = Prio;
 208          }
 209       }
 210
 211       if (instVer == true && Max < 1000)
 212       {
 213          /* Not having seen the Pref yet means we have a specific pin below 1000
 214             on a version below the current installed one, so ignore the specific pin
 215             as this would be a downgrade otherwise */
 216          if (PrefSeen == false || Pref.end() == true)
 217          {
 218             Pref = Ver;
 219             PrefSeen = true;
 220          }
 221          /* Elevate our current selection (or the status file itself)
 222             to the Pseudo-status priority. */
 223          Max = 1000;
 224
 225          // Fast path optimize.
 226          if (StatusOverride == false)
 227             break;
 228       }
 229    }
 230    // If we do not find our candidate, use the one with the highest pin.
 231    // This means that if there is a version available with pin > 0; there
 232    // will always be a candidate (Closes: #512318)
 233    if (!Pref.IsGood() && MaxAlt > 0)
 234        Pref = PrefAlt;
 235
 236    return Pref;
 237 }
 238                                                                         /*}}}*/
 239 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 240 // ---------------------------------------------------------------------
 241 /* For performance we have 3 tables, the default table, the main cache
 242    table (hashed to the cache). A blank package name indicates the pin
 243    belongs to the default table. Order of insertion matters here, the
 244    earlier defaults override later ones. */
 245 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 246                           string Data,signed short Priority)
 247 {
 248    if (Name.empty() == true)
 249    {
 250       Pin *P = &*Defaults.insert(Defaults.end(),Pin());
 251       P->Type = Type;
 252       P->Priority = Priority;
 253       P->Data = Data;
 254       return;
 255    }
 256
 257    size_t found = Name.rfind(':');
 258    string Arch;
 259    if (found != string::npos) {
 260       Arch = Name.substr(found+1);
 261       Name.erase(found);
 262    }
 263
 264    // Allow pinning by wildcards
 265    // TODO: Maybe we should always prefer specific pins over non-
 266    // specific ones.
 267    if (Name[0] == '/' || Name.find_first_of("*[?") != string::npos)
 268    {
 269       pkgVersionMatch match(Data, Type);
 270       for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
 271          if (match.ExpressionMatches(Name, G.Name()))
 272          {
 273             if (Arch.empty() == false)
 274                CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
 275             else
 276                CreatePin(Type, G.Name(), Data, Priority);
 277          }
 278       return;
 279    }
 280
 281    // find the package (group) this pin applies to
 282    pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
 283    bool matched = false;
 284    if (Grp.end() == false)
 285    {
 286       std::string MatchingArch;
 287       if (Arch.empty() == true)
 288          MatchingArch = Cache->NativeArch();
 289       else
 290          MatchingArch = Arch;
 291       APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
 292       for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 293       {
 294          if (pams(Pkg.Arch()) == false)
 295             continue;
 296          Pin *P = Pins + Pkg->ID;
 297          // the first specific stanza for a package is the ruler,
 298          // all others need to be ignored
 299          if (P->Type != pkgVersionMatch::None)
 300             P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
 301          P->Type = Type;
 302          P->Priority = Priority;
 303          P->Data = Data;
 304          matched = true;
 305       }
 306    }
 307
 308    if (matched == false)
 309    {
 310       PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
 311       if (Arch.empty() == false)
 312          P->Pkg.append(":").append(Arch);
 313       P->Type = Type;
 314       P->Priority = Priority;
 315       P->Data = Data;
 316       return;
 317    }
 318 }
 319                                                                         /*}}}*/
 320 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 321 // ---------------------------------------------------------------------
 322 /* */
 323 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 324 {
 325    const Pin &PPkg = Pins[Pkg->ID];
 326    if (PPkg.Type == pkgVersionMatch::None)
 327       return pkgCache::VerIterator(*Pkg.Cache());
 328
 329    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 330    return Match.Find(Pkg);
 331 }
 332                                                                         /*}}}*/
 333 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 334 // ---------------------------------------------------------------------
 335 /* */
 336 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 337 {
 338    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 339    {
 340       // In this case 0 means default priority
 341       if (Pins[Pkg->ID].Priority == 0)
 342          return 989;
 343       return Pins[Pkg->ID].Priority;
 344    }
 345
 346    return 0;
 347 }
 348 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
 349 {
 350    return PFPriority[File->ID];
 351 }
 352                                                                         /*}}}*/
 353 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 354 // ---------------------------------------------------------------------
 355 /* The preference file is a user generated file so the parser should
 356    therefore be a bit more friendly by allowing comments and new lines
 357    all over the place rather than forcing a special format */
 358 class PreferenceSection : public pkgTagSection
 359 {
 360    void TrimRecord(bool /*BeforeRecord*/, const char* &End)
 361    {
 362       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 363          if (Stop[0] == '#')
 364             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 365    }
 366 };
 367                                                                         /*}}}*/
 368 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 369 // ---------------------------------------------------------------------
 370 /* This will load each pin file in the given dir into a Policy. If the
 371    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 372    Note also that this method will issue a warning if the dir does not
 373    exists but it will return true in this case! */
 374 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 375 {
 376    if (Dir.empty() == true)
 377       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 378
 379    if (DirectoryExists(Dir) == false)
 380    {
 381       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 382       return true;
 383    }
 384
 385    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 386
 387    // Read the files
 388    for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
 389       if (ReadPinFile(Plcy, *I) == false)
 390          return false;
 391    return true;
 392 }
 393                                                                         /*}}}*/
 394 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 395 // ---------------------------------------------------------------------
 396 /* I'd like to see the preferences file store more than just pin information
 397    but right now that is the only stuff I have to store. Later there will
 398    have to be some kind of combined super parser to get the data into all
 399    the right classes.. */
 400 bool ReadPinFile(pkgPolicy &Plcy,string File)
 401 {
 402    if (File.empty() == true)
 403       File = _config->FindFile("Dir::Etc::Preferences");
 404
 405    if (RealFileExists(File) == false)
 406       return true;
 407
 408    FileFd Fd(File,FileFd::ReadOnly);
 409    pkgTagFile TF(&Fd);
 410    if (_error->PendingError() == true)
 411       return false;
 412
 413    PreferenceSection Tags;
 414    while (TF.Step(Tags) == true)
 415    {
 416       // can happen when there are only comments in a record
 417       if (Tags.Count() == 0)
 418          continue;
 419
 420       string Name = Tags.FindS("Package");
 421       if (Name.empty() == true)
 422          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 423       if (Name == "*")
 424          Name = string();
 425
 426       const char *Start;
 427       const char *End;
 428       if (Tags.Find("Pin",Start,End) == false)
 429          continue;
 430
 431       const char *Word = Start;
 432       for (; Word != End && isspace(*Word) == 0; Word++);
 433
 434       // Parse the type..
 435       pkgVersionMatch::MatchType Type;
 436       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 437          Type = pkgVersionMatch::Version;
 438       else if (stringcasecmp(Start,Word,"release") == 0)
 439          Type = pkgVersionMatch::Release;
 440       else if (stringcasecmp(Start,Word,"origin") == 0)
 441          Type = pkgVersionMatch::Origin;
 442       else
 443       {
 444          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 445          continue;
 446       }
 447       for (; Word != End && isspace(*Word) != 0; Word++);
 448
 449       short int priority = Tags.FindI("Pin-Priority", 0);
 450       if (priority == 0)
 451       {
 452          _error->Warning(_("No priority (or zero) specified for pin"));
 453          continue;
 454       }
 455
 456       istringstream s(Name);
 457       string pkg;
 458       while(!s.eof())
 459       {
 460          s >> pkg;
 461          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 462       };
 463    }
 464
 465    Plcy.InitDefaults();
 466    return true;
 467 }
 468                                                                         /*}}}*/