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