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