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