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    See man apt_preferences for what value means what.
  12
  13    ##################################################################### */
  14                                                                         /*}}}*/
  15 // Include Files                                                        /*{{{*/
  16 #include<config.h>
  17
  18 #include <apt-pkg/policy.h>
  19 #include <apt-pkg/configuration.h>
  20 #include <apt-pkg/cachefilter.h>
  21 #include <apt-pkg/tagfile.h>
  22 #include <apt-pkg/strutl.h>
  23 #include <apt-pkg/fileutl.h>
  24 #include <apt-pkg/error.h>
  25 #include <apt-pkg/sptr.h>
  26 #include <apt-pkg/cacheiterators.h>
  27 #include <apt-pkg/pkgcache.h>
  28 #include <apt-pkg/versionmatch.h>
  29
  30 #include <ctype.h>
  31 #include <stddef.h>
  32 #include <string.h>
  33 #include <string>
  34 #include <vector>
  35 #include <iostream>
  36 #include <sstream>
  37
  38 #include <apti18n.h>
  39                                                                         /*}}}*/
  40
  41 using namespace std;
  42
  43 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  44 // ---------------------------------------------------------------------
  45 /* Set the defaults for operation. The default mode with no loaded policy
  46    file matches the V0 policy engine. */
  47 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  48 {
  49    if (Owner == 0)
  50       return;
  51    PFPriority = new signed short[Owner->Head().PackageFileCount];
  52    Pins = new Pin[Owner->Head().PackageCount];
  53
  54    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  55       Pins[I].Type = pkgVersionMatch::None;
  56
  57    // The config file has a master override.
  58    string DefRel = _config->Find("APT::Default-Release");
  59    if (DefRel.empty() == false)
  60    {
  61       bool found = false;
  62       // FIXME: make ExpressionMatches static to use it here easily
  63       pkgVersionMatch vm("", pkgVersionMatch::None);
  64       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
  65       {
  66          if (vm.ExpressionMatches(DefRel, F.Archive()) ||
  67              vm.ExpressionMatches(DefRel, F.Codename()) ||
  68              vm.ExpressionMatches(DefRel, F.Version()) ||
  69              (DefRel.length() > 2 && DefRel[1] == '='))
  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.Flagged(pkgCache::Flag::NotSource))
  90          PFPriority[I->ID] = 100;
  91       else if (I.Flagged(pkgCache::Flag::ButAutomaticUpgrades))
  92          PFPriority[I->ID] = 100;
  93       else if (I.Flagged(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    StatusOverride = false;
 101    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end(); ++I)
 102    {
 103       pkgVersionMatch Match(I->Data,I->Type);
 104       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 105       {
 106          if (Fixed[F->ID] == false && Match.FileMatch(F) == true)
 107          {
 108             PFPriority[F->ID] = I->Priority;
 109
 110             if (PFPriority[F->ID] >= 1000)
 111                StatusOverride = true;
 112
 113             Fixed[F->ID] = true;
 114          }
 115       }
 116    }
 117
 118    if (_config->FindB("Debug::pkgPolicy",false) == true)
 119       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
 120          std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
 121
 122    return true;
 123 }
 124                                                                         /*}}}*/
 125 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 126 // ---------------------------------------------------------------------
 127 /* Evaluate the package pins and the default list to deteremine what the
 128    best package is. */
 129 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
 130 {
 131    // Look for a package pin and evaluate it.
 132    signed Max = GetPriority(Pkg);
 133    pkgCache::VerIterator Pref = GetMatch(Pkg);
 134
 135    // Alternatives in case we can not find our package pin (Bug#512318).
 136    signed MaxAlt = 0;
 137    pkgCache::VerIterator PrefAlt;
 138
 139    // no package = no candidate version
 140    if (Pkg.end() == true)
 141       return Pref;
 142
 143    // packages with a pin lower than 0 have no newer candidate than the current version
 144    if (Max < 0)
 145       return Pkg.CurrentVer();
 146
 147    /* Falling through to the default version.. Setting Max to zero
 148       effectively excludes everything <= 0 which are the non-automatic
 149       priorities.. The status file is given a prio of 100 which will exclude
 150       not-automatic sources, except in a single shot not-installed mode.
 151
 152       The user pin is subject to the same priority rules as default
 153       selections. Thus there are two ways to create a pin - a pin that
 154       tracks the default when the default is taken away, and a permanent
 155       pin that stays at that setting.
 156     */
 157    bool PrefSeen = false;
 158    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
 159    {
 160       /* Lets see if this version is the installed version */
 161       bool instVer = (Pkg.CurrentVer() == Ver);
 162
 163       if (Pref == Ver)
 164          PrefSeen = true;
 165
 166       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
 167       {
 168          /* If this is the status file, and the current version is not the
 169             version in the status file (ie it is not installed, or somesuch)
 170             then it is not a candidate for installation, ever. This weeds
 171             out bogus entries that may be due to config-file states, or
 172             other. */
 173          if (VF.File().Flagged(pkgCache::Flag::NotSource) && instVer == false)
 174             continue;
 175
 176          signed Prio = PFPriority[VF.File()->ID];
 177          if (Prio > Max)
 178          {
 179             Pref = Ver;
 180             Max = Prio;
 181             PrefSeen = true;
 182          }
 183          if (Prio > MaxAlt)
 184          {
 185             PrefAlt = Ver;
 186             MaxAlt = Prio;
 187          }
 188       }
 189
 190       if (instVer == true && Max < 1000)
 191       {
 192          /* Not having seen the Pref yet means we have a specific pin below 1000
 193             on a version below the current installed one, so ignore the specific pin
 194             as this would be a downgrade otherwise */
 195          if (PrefSeen == false || Pref.end() == true)
 196          {
 197             Pref = Ver;
 198             PrefSeen = true;
 199          }
 200          /* Elevate our current selection (or the status file itself) so that only
 201             a downgrade can override it from now on */
 202          Max = 999;
 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 = Cache->FindGrp(Name);
 262    bool matched = false;
 263    if (Grp.end() == false)
 264    {
 265       std::string MatchingArch;
 266       if (Arch.empty() == true)
 267          MatchingArch = Cache->NativeArch();
 268       else
 269          MatchingArch = Arch;
 270       APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
 271       for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
 272       {
 273          if (pams(Pkg.Arch()) == false)
 274             continue;
 275          Pin *P = Pins + Pkg->ID;
 276          // the first specific stanza for a package is the ruler,
 277          // all others need to be ignored
 278          if (P->Type != pkgVersionMatch::None)
 279             P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
 280          P->Type = Type;
 281          P->Priority = Priority;
 282          P->Data = Data;
 283          matched = true;
 284       }
 285    }
 286
 287    if (matched == false)
 288    {
 289       PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
 290       if (Arch.empty() == false)
 291          P->Pkg.append(":").append(Arch);
 292       P->Type = Type;
 293       P->Priority = Priority;
 294       P->Data = Data;
 295       return;
 296    }
 297 }
 298                                                                         /*}}}*/
 299 // Policy::GetMatch - Get the matching version for a package pin        /*{{{*/
 300 // ---------------------------------------------------------------------
 301 /* */
 302 pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
 303 {
 304    const Pin &PPkg = Pins[Pkg->ID];
 305    if (PPkg.Type == pkgVersionMatch::None)
 306       return pkgCache::VerIterator(*Pkg.Cache());
 307
 308    pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 309    return Match.Find(Pkg);
 310 }
 311                                                                         /*}}}*/
 312 // Policy::GetPriority - Get the priority of the package pin            /*{{{*/
 313 // ---------------------------------------------------------------------
 314 /* */
 315 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
 316 {
 317    if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
 318       return Pins[Pkg->ID].Priority;
 319    return 0;
 320 }
 321 APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
 322 {
 323    return PFPriority[File->ID];
 324 }
 325                                                                         /*}}}*/
 326 // PreferenceSection class - Overriding the default TrimRecord method   /*{{{*/
 327 // ---------------------------------------------------------------------
 328 /* The preference file is a user generated file so the parser should
 329    therefore be a bit more friendly by allowing comments and new lines
 330    all over the place rather than forcing a special format */
 331 class PreferenceSection : public pkgTagSection
 332 {
 333    void TrimRecord(bool /*BeforeRecord*/, const char* &End)
 334    {
 335       for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
 336          if (Stop[0] == '#')
 337             Stop = (const char*) memchr(Stop,'\n',End-Stop);
 338    }
 339 };
 340                                                                         /*}}}*/
 341 // ReadPinDir - Load the pin files from this dir into a Policy          /*{{{*/
 342 // ---------------------------------------------------------------------
 343 /* This will load each pin file in the given dir into a Policy. If the
 344    given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
 345    Note also that this method will issue a warning if the dir does not
 346    exists but it will return true in this case! */
 347 bool ReadPinDir(pkgPolicy &Plcy,string Dir)
 348 {
 349    if (Dir.empty() == true)
 350       Dir = _config->FindDir("Dir::Etc::PreferencesParts");
 351
 352    if (DirectoryExists(Dir) == false)
 353    {
 354       _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
 355       return true;
 356    }
 357
 358    vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
 359
 360    // Read the files
 361    for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
 362       if (ReadPinFile(Plcy, *I) == false)
 363          return false;
 364    return true;
 365 }
 366                                                                         /*}}}*/
 367 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 368 // ---------------------------------------------------------------------
 369 /* I'd like to see the preferences file store more than just pin information
 370    but right now that is the only stuff I have to store. Later there will
 371    have to be some kind of combined super parser to get the data into all
 372    the right classes.. */
 373 bool ReadPinFile(pkgPolicy &Plcy,string File)
 374 {
 375    if (File.empty() == true)
 376       File = _config->FindFile("Dir::Etc::Preferences");
 377
 378    if (RealFileExists(File) == false)
 379       return true;
 380
 381    FileFd Fd(File,FileFd::ReadOnly);
 382    pkgTagFile TF(&Fd);
 383    if (_error->PendingError() == true)
 384       return false;
 385
 386    PreferenceSection Tags;
 387    while (TF.Step(Tags) == true)
 388    {
 389       // can happen when there are only comments in a record
 390       if (Tags.Count() == 0)
 391          continue;
 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                                                                         /*}}}*/