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/tagfile.h>
  31 #include <apt-pkg/strutl.h>
  32 #include <apt-pkg/fileutl.h>
  33 #include <apt-pkg/error.h>
  34 #include <apt-pkg/sptr.h>
  35
  36 #include <iostream>
  37 #include <sstream>
  38
  39 #include <apti18n.h>
  40                                                                         /*}}}*/
  41
  42 using namespace std;
  43
  44 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  45 // ---------------------------------------------------------------------
  46 /* Set the defaults for operation. The default mode with no loaded policy
  47    file matches the V0 policy engine. */
  48 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  49 {
  50    if (Owner == 0 || &(Owner->Head()) == 0)
  51       return;
  52    PFPriority = new signed short[Owner->Head().PackageFileCount];
  53    Pins = new Pin[Owner->Head().PackageCount];
  54
  55    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  56       Pins[I].Type = pkgVersionMatch::None;
  57
  58    // The config file has a master override.
  59    string DefRel = _config->Find("APT::Default-Release");
  60    if (DefRel.empty() == false)
  61    {
  62       bool found = false;
  63       // FIXME: make ExpressionMatches static to use it here easily
  64       pkgVersionMatch vm("", pkgVersionMatch::None);
  65       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
  66       {
  67          if ((F->Archive != 0 && vm.ExpressionMatches(DefRel, F.Archive()) == true) ||
  68              (F->Codename != 0 && vm.ExpressionMatches(DefRel, F.Codename()) == true) ||
  69              (F->Version != 0 && vm.ExpressionMatches(DefRel, F.Version()) == true))
  70             found = true;
  71       }
  72       if (found == false)
  73          _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
  74       else
  75          CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  76    }
  77    InitDefaults();
  78 }
  79                                                                         /*}}}*/
  80 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  81 // ---------------------------------------------------------------------
  82 /* */
  83 bool pkgPolicy::InitDefaults()
  84 {
  85    // Initialize the priorities based on the status of the package file
  86    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
  87    {
  88       PFPriority[I->ID] = 500;
  89       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  90          PFPriority[I->ID] = 100;
  91       else if ((I->Flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
  92          PFPriority[I->ID] = 100;
  93       else if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  94          PFPriority[I->ID] = 1;
  95    }
  96
  97    // Apply the defaults..
  98    SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  99    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
 100    signed Cur = 989;
 101    StatusOverride = false;
 102    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
 103         ++I, --Cur)
 104    {
 105       pkgVersionMatch Match(I->Data,I->Type);
 106       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 107       {
 108          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
 109          {
 110             if (I->Priority != 0 && I->Priority > 0)
 111                Cur = I->Priority;
 112
 113             if (I->Priority < 0)
 114                PFPriority[F->ID] =  I->Priority;
 115             else
 116                PFPriority[F->ID] = Cur;
 117
 118             if (PFPriority[F->ID] > 1000)
 119                StatusOverride = true;
 120
 121             Fixed[F->ID] = true;
 122          }
 123       }
 124    }
 125
 126    if (_config->FindB("Debug::pkgPolicy",false) == true)
 127       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 128          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 129
 130    return true;
 131 }
 132                                                                         /*}}}*/
 133 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 134 // ---------------------------------------------------------------------
 135 /* Evaluate the package pins and the default list to deteremine what the
 136    best package is. */
 137 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 138 {
 139    // Look for a package pin and evaluate it.
 140    signed Max = GetPriority(Pkg);
 141    pkgCache::VerIterator Pref = GetMatch(Pkg);
 142
 143    // Alternatives in case we can not find our package pin (Bug#512318).
 144    signed MaxAlt = 0;
 145    pkgCache::VerIterator PrefAlt;
 146
 147    // no package = no candidate version
 148    if (Pkg.end() == true)
 149       return Pref;
 150
 151    // packages with a pin lower than 0 have no newer candidate than the current version
 152    if (Max < 0)
 153       return Pkg.CurrentVer();
 154
 155    /* Falling through to the default version.. Setting Max to zero
 156       effectively excludes everything <= 0 which are the non-automatic
 157       priorities.. The status file is given a prio of 100 which will exclude
 158       not-automatic sources, except in a single shot not-installed mode.
 159       The second pseduo-status file is at prio 1000, above which will permit
 160       the user to force-downgrade things.
 161
 162       The user pin is subject to the same priority rules as default
 163       selections. Thus there are two ways to create a pin - a pin that
 164       tracks the default when the default is taken away, and a permanent
 165       pin that stays at that setting.
 166     */
 167    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
 168    {
 169       /* Lets see if this version is the installed version */
 170       bool instVer = (Pkg.CurrentVer() == Ver);
 171
 172       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
 173       {
 174          /* If this is the status file, and the current version is not the
 175             version in the status file (ie it is not installed, or somesuch)
 176             then it is not a candidate for installation, ever. This weeds
 177             out bogus entries that may be due to config-file states, or
 178             other. */
 179          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 180              instVer == false)
 181             continue;
 182
 183          signed Prio = PFPriority[VF.File()->ID];
 184          if (Prio > Max)
 185          {
 186             Pref = Ver;
 187             Max = Prio;
 188          }
 189          if (Prio > MaxAlt)
 190          {
 191             PrefAlt = Ver;
 192             MaxAlt = Prio;
 193          }
 194       }
 195
 196       if (instVer == true && Max < 1000)
 197       {
 198          /* Elevate our current selection (or the status file itself)
 199             to the Pseudo-status priority. */
 200          if (Pref.end() == true)
 201             Pref = Ver;
 202          Max = 1000;
 203
 204          // Fast path optimize.
 205          if (StatusOverride == false)
 206             break;
 207       }
 208    }
 209    // If we do not find our candidate, use the one with the highest pin.
 210    // This means that if there is a version available with pin > 0; there
 211    // will always be a candidate (Closes: #512318)
 212    if (!Pref.IsGood() && MaxAlt > 0)
 213        Pref = PrefAlt;
 214
 215    return Pref;
 216 }
 217                                                                         /*}}}*/
 218 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 219 // ---------------------------------------------------------------------
 220 /* For performance we have 3 tables, the default table, the main cache
 221    table (hashed to the cache). A blank package name indicates the pin
 222    belongs to the default table. Order of insertion matters here, the
 223    earlier defaults override later ones. */
 224 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 225                           string Data,signed short Priority)
 226 {
 227    if (Name.empty() == true)
 228    {
 229       Pin *P = &*Defaults.insert(Defaults.end(),Pin());
 230       P->Type = Type;
 231       P->Priority = Priority;
 232       P->Data = Data;
 233       return;
 234    }
 235
 236    size_t found = Name.rfind(':');
 237    string Arch;
 238    if (found != string::npos) {
 239       Arch = Name.substr(found+1);
 240       Name.erase(found);
 241    }
 242
 243    // Allow pinning by wildcards
 244    // TODO: Maybe we should always prefer specific pins over non-
 245    // specific ones.
 246    if (Name[0] == '/' || Name.find_first_of("*[?") != string::npos)
 247    {
 248       pkgVersionMatch match(Data, Type);
 249       for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
 250          if (match.ExpressionMatches(Name, G.Name()))
 251          {
 252             if (Arch.empty() == false)
 253                CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
 254             else
 255                CreatePin(Type, G.Name(), Data, Priority);
 256          }
 257       return;
 258    }
 259
 260    // find the package (group) this pin applies to
 261    pkgCache::GrpIterator Grp;
 262    pkgCache::PkgIterator Pkg;
 263    if (Arch.empty() == false)
 264       Pkg = Cache->FindPkg(Name, Arch);
 265    else {
 266       Grp = Cache->FindGrp(Name);
 267       if (Grp.end() == false)
 268          Pkg = Grp.PackageList();
 269    }
 270
 271    if (Pkg.end() == true)
 272    {
 273       PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
 274       if (Arch.empty() == false)
 275          P->Pkg.append(":").append(Arch);
 276       P->Type = Type;
 277       P->Priority = Priority;
 278       P->Data = Data;
 279       return;
 280    }
 281
 282    for (; Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 283    {
 284       Pin *P = Pins + Pkg->ID;
 285       // the first specific stanza for a package is the ruler,
 286       // all others need to be ignored
 287       if (P->Type != pkgVersionMatch::None)
 288          P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
 289       P->Type = Type;
 290       P->Priority = Priority;
 291       P->Data = Data;
 292       if (Grp.end() == true)
 293          break;
 294    }
 295 }
 296                                                                         /*}}}*/
 297 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 298 // ---------------------------------------------------------------------
 299 /* */
 300 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 301 {
 302    const Pin &PPkg = Pins[Pkg->ID];
 303    if (PPkg.Type == pkgVersionMatch::None)
 304       return pkgCache::VerIterator(*Pkg.Cache());
 305
 306    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 307    return Match.Find(Pkg);
 308 }
 309                                                                         /*}}}*/
 310 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 311 // ---------------------------------------------------------------------
 312 /* */
 313 signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 314 {
 315    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 316    {
 317       // In this case 0 means default priority
 318       if (Pins[Pkg->ID].Priority == 0)
 319          return 989;
 320       return Pins[Pkg->ID].Priority;
 321    }
 322
 323    return 0;
 324 }
 325 signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
 326 {
 327    return PFPriority[File->ID];
 328 }
 329                                                                         /*}}}*/
 330 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 331 // ---------------------------------------------------------------------
 332 /* The preference file is a user generated file so the parser should
 333    therefore be a bit more friendly by allowing comments and new lines
 334    all over the place rather than forcing a special format */
 335 class PreferenceSection : public pkgTagSection
 336 {
 337    void TrimRecord(bool BeforeRecord, const char* &End)
 338    {
 339       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 340          if (Stop[0] == '#')
 341             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 342    }
 343 };
 344                                                                         /*}}}*/
 345 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 346 // ---------------------------------------------------------------------
 347 /* This will load each pin file in the given dir into a Policy. If the
 348    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 349    Note also that this method will issue a warning if the dir does not
 350    exists but it will return true in this case! */
 351 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 352 {
 353    if (Dir.empty() == true)
 354       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 355
 356    if (DirectoryExists(Dir) == false)
 357    {
 358       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 359       return true;
 360    }
 361
 362    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 363
 364    // Read the files
 365    for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
 366       if (ReadPinFile(Plcy, *I) == false)
 367          return false;
 368    return true;
 369 }
 370                                                                         /*}}}*/
 371 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 372 // ---------------------------------------------------------------------
 373 /* I'd like to see the preferences file store more than just pin information
 374    but right now that is the only stuff I have to store. Later there will
 375    have to be some kind of combined super parser to get the data into all
 376    the right classes.. */
 377 bool ReadPinFile(pkgPolicy &Plcy,string File)
 378 {
 379    if (File.empty() == true)
 380       File = _config->FindFile("Dir::Etc::Preferences");
 381
 382    if (RealFileExists(File) == false)
 383       return true;
 384
 385    FileFd Fd(File,FileFd::ReadOnly);
 386    pkgTagFile TF(&Fd);
 387    if (_error->PendingError() == true)
 388       return false;
 389
 390    PreferenceSection Tags;
 391    while (TF.Step(Tags) == true)
 392    {
 393       string Name = Tags.FindS("Package");
 394       if (Name.empty() == true)
 395          return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
 396       if (Name == "*")
 397          Name = string();
 398
 399       const char *Start;
 400       const char *End;
 401       if (Tags.Find("Pin",Start,End) == false)
 402          continue;
 403
 404       const char *Word = Start;
 405       for (; Word != End && isspace(*Word) == 0; Word++);
 406
 407       // Parse the type..
 408       pkgVersionMatch::MatchType Type;
 409       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 410          Type = pkgVersionMatch::Version;
 411       else if (stringcasecmp(Start,Word,"release") == 0)
 412          Type = pkgVersionMatch::Release;
 413       else if (stringcasecmp(Start,Word,"origin") == 0)
 414          Type = pkgVersionMatch::Origin;
 415       else
 416       {
 417          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 418          continue;
 419       }
 420       for (; Word != End && isspace(*Word) != 0; Word++);
 421
 422       short int priority = Tags.FindI("Pin-Priority", 0);
 423       if (priority == 0)
 424       {
 425          _error->Warning(_("No priority (or zero) specified for pin"));
 426          continue;
 427       }
 428
 429       istringstream s(Name);
 430       string pkg;
 431       while(!s.eof())
 432       {
 433          s >> pkg;
 434          Plcy.CreatePin(Type, pkg, string(Word,End),priority);
 435       };
 436    }
 437
 438    Plcy.InitDefaults();
 439    return true;
 440 }
 441                                                                         /*}}}*/