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